1
|
Naseem Y, Zhang C, Zhou X, Dong J, Xie J, Zhang H, Agboyibor C, Bi Y, Liu H. Inhibitors Targeting the F-BOX Proteins. Cell Biochem Biophys 2023; 81:577-597. [PMID: 37624574 DOI: 10.1007/s12013-023-01160-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2023] [Indexed: 08/26/2023]
Abstract
F-box proteins are involved in multiple cellular processes through ubiquitylation and consequent degradation of targeted substrates. Any significant mutation in F-box protein-mediated proteolysis can cause human malformations. The various cellular processes F-box proteins involved include cell proliferation, apoptosis, invasion, angiogenesis, and metastasis. To target F-box proteins and their associated signaling pathways for cancer treatment, researchers have developed thousands of F-box inhibitors. The most advanced inhibitor of FBW7, NVD-BK M120, is a powerful P13 kinase inhibitor that has been proven to bring about apoptosis in cancerous human lung cells by disrupting levels of the protein known as MCL1. Moreover, F-box Inhibitors have demonstrated their efficacy for treating certain cancers through targeting particular mutated proteins. This paper explores the key studies on how F-box proteins act and their contribution to malignancy development, which fabricates an in-depth perception of inhibitors targeting the F-box proteins and their signaling pathways that eventually isolate the most promising approach to anti-cancer treatments.
Collapse
Affiliation(s)
- Yalnaz Naseem
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China
| | - Chaofeng Zhang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China
| | - Xinyi Zhou
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China
| | - Jianshu Dong
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China.
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China.
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China.
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China.
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China.
| | - Jiachong Xie
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China
| | - Huimin Zhang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China
| | - Clement Agboyibor
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China
| | - YueFeng Bi
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China.
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China.
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China.
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China.
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China.
| | - Hongmin Liu
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou, 450001, China.
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou, 450001, China.
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Zhengzhou University, Zhengzhou, 450001, China.
- Key Laboratory of Henan Province for Drug Quality and Evaluation, Zhengzhou University, Zhengzhou, 450001, China.
| |
Collapse
|
2
|
Kim DJ, Yi YW, Seong YS. Beta-Transducin Repeats-Containing Proteins as an Anticancer Target. Cancers (Basel) 2023; 15:4248. [PMID: 37686524 PMCID: PMC10487276 DOI: 10.3390/cancers15174248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
Beta-transducin repeat-containing proteins (β-TrCPs) are E3-ubiquitin-ligase-recognizing substrates and regulate proteasomal degradation. The degradation of β-TrCPs' substrates is tightly controlled by various external and internal signaling and confers diverse cellular processes, including cell cycle progression, apoptosis, and DNA damage response. In addition, β-TrCPs function to regulate transcriptional activity and stabilize a set of substrates by distinct mechanisms. Despite the association of β-TrCPs with tumorigenesis and tumor progression, studies on the mechanisms of the regulation of β-TrCPs' activity have been limited. In this review, we studied publications on the regulation of β-TrCPs themselves and analyzed the knowledge gaps to understand and modulate β-TrCPs' activity in the future.
Collapse
Affiliation(s)
- Dong Joon Kim
- Department of Microbiology, College of Medicine, Dankook University, Cheonan-si 31116, Chungcheongnam-do, Republic of Korea;
- Multidrug-Resistant Refractory Cancer Convergence Research Center (MRCRC), Dankook University, Cheonan-si 31116, Chungcheongnam-do, Republic of Korea
- Department of Pathophysiology, School of Basic Medical Sciences, Academy of Medical Science, College of Medicine, Zhengzhou University, Zhengzhou 450008, China
- China-US (Henan) Hormel Cancer Institute, Zhengzhou 450008, China
| | - Yong Weon Yi
- Multidrug-Resistant Refractory Cancer Convergence Research Center (MRCRC), Dankook University, Cheonan-si 31116, Chungcheongnam-do, Republic of Korea
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan-si 31116, Chungcheongnam-do, Republic of Korea
| | - Yeon-Sun Seong
- Multidrug-Resistant Refractory Cancer Convergence Research Center (MRCRC), Dankook University, Cheonan-si 31116, Chungcheongnam-do, Republic of Korea
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan-si 31116, Chungcheongnam-do, Republic of Korea
| |
Collapse
|
3
|
Fang M, Wu HK, Pei Y, Zhang Y, Gao X, He Y, Chen G, Lv F, Jiang P, Li Y, Li W, Jiang P, Wang L, Ji J, Hu X, Xiao RP. E3 ligase MG53 suppresses tumor growth by degrading cyclin D1. Signal Transduct Target Ther 2023; 8:263. [PMID: 37414783 PMCID: PMC10326024 DOI: 10.1038/s41392-023-01458-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 04/09/2023] [Accepted: 04/22/2023] [Indexed: 07/08/2023] Open
Abstract
Due to the essential role of cyclin D1 in regulating transition from G1 to S phase in cell cycle, aberrant cyclin D1 expression is a major oncogenic event in many types of cancers. In particular, the dysregulation of ubiquitination-dependent degradation of cyclin D1 contributes to not only the pathogenesis of malignancies but also the refractory to cancer treatment regiments with CDK4/6 inhibitors. Here we show that in colorectal and gastric cancer patients, MG53 is downregulated in more than 80% of tumors compared to the normal gastrointestinal tissues from the same patient, and the reduced MG53 expression is correlated with increased cyclin D1 abundance and inferior survival. Mechanistically, MG53 catalyzes the K48-linked ubiquitination and subsequent degradation of cyclin D1. Thus, increased expression of MG53 leads to cell cycle arrest at G1, and thereby markedly suppresses cancer cell proliferation in vitro as well as tumor growth in mice with xenograft tumors or AOM/DSS induced-colorectal cancer. Consistently, MG53 deficiency results in accumulation of cyclin D1 protein and accelerates cancer cell growth both in culture and in animal models. These findings define MG53 as a tumor suppressor via facilitating cyclin D1 degradation, highlighting the therapeutic potential of targeting MG53 in treating cancers with dysregulated cyclin D1 turnover.
Collapse
Affiliation(s)
- Meng Fang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, 100871, Beijing, China
| | - Hong-Kun Wu
- Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, 310003, Hangzhou, China
| | - Yumeng Pei
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, 100871, Beijing, China
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
- Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China
| | - Xiangyu Gao
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Gastrointestinal Tumor Center, Peking University Cancer Hospital & Institute, 100142, Beijing, China
| | - Yanyun He
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, 100871, Beijing, China
| | - Gengjia Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
| | - Fengxiang Lv
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
- Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China
| | - Peng Jiang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
| | - Yumei Li
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
| | - Wenwen Li
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China
| | - Peng Jiang
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Lin Wang
- Research Center for Tissue Engineering and Regenerative Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Jiafu Ji
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Gastrointestinal Tumor Center, Peking University Cancer Hospital & Institute, 100142, Beijing, China.
| | - Xinli Hu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China.
- Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China.
| | - Rui-Ping Xiao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, 100871, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, 100871, Beijing, China.
- Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, 100871, Beijing, China.
| |
Collapse
|
4
|
Ma C, Wang D, Tian Z, Gao W, Zang Y, Qian L, Xu X, Jia J, Liu Z. USP13 deubiquitinates and stabilizes cyclin D1 to promote gastric cancer cell cycle progression and cell proliferation. Oncogene 2023:10.1038/s41388-023-02739-x. [PMID: 37311811 DOI: 10.1038/s41388-023-02739-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/09/2023] [Accepted: 05/24/2023] [Indexed: 06/15/2023]
Abstract
The reversible post-translational modifications of protein ubiquitination and deubiquitination play a crucial regulatory role in cellular homeostasis. Deubiquitinases (DUBs) are responsible for the removal of ubiquitin from the protein substrates. The dysregulation of the DUBs may give rise to the occurrence and development of tumors. In this study, we investigated the gastric cancer (GC) data from the TCGA and GEO databases and found that ubiquitin-specific protease USP13 was significantly up-regulated in GC samples. The higher expression of USP13 was associated with the worse prognosis and shorter overall survival (OS) of GC patients. Enforced expression of USP13 in GC cells promoted the cell cycle progression and cell proliferation in an enzymatically dependent manner. Conversely, suppression of USP13 led to GC cell cycle arrest in G1 phase and the inhibition of cell proliferation. Nude mouse experiments indicated that depletion of USP13 in GC cells dramatically suppressed tumor growth in vivo. Mechanistically, USP13 physically bound to the N-terminal domain of cyclin D1 and removed its K48- but not K63-linked polyubiquitination chain, thereby stabilizing and increasing cyclin D1. Furthermore, re-expression of cyclin D1 partially reversed the cell cycle arrest and cell proliferation inhibition induced by USP13 depletion in GC cells. Additionally, USP13 protein abundance was positively correlated with the protein level of cyclin D1 in human GC tissues. Taken together, our data demonstrate that USP13 deubiquitinates and stabilizes cyclin D1, thereby promoting cell cycle progression and cell proliferation in GC. These findings suggest that USP13 might be a promising therapeutic target for the treatment of GC.
Collapse
Affiliation(s)
- Cunying Ma
- Department of Biochemistry and Molecular Biology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Dandan Wang
- Department of Microbiology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Zhuangfei Tian
- Department of Biochemistry and Molecular Biology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Wenrong Gao
- Department of Microbiology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Yichen Zang
- Department of Biochemistry and Molecular Biology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Lilin Qian
- Department of Biochemistry and Molecular Biology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Xia Xu
- Department of Biochemistry and Molecular Biology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Jihui Jia
- Department of Microbiology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Zhifang Liu
- Department of Biochemistry and Molecular Biology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China.
| |
Collapse
|
5
|
Li CM, Zhang J, Wu W, Zhu Z, Li F, Wu D, Wang XJ, Xie CM, Gong JP. FBXO43 increases CCND1 stability to promote hepatocellular carcinoma cell proliferation and migration. Front Oncol 2023; 13:1138348. [PMID: 36937431 PMCID: PMC10020529 DOI: 10.3389/fonc.2023.1138348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
Background and Aims Abnormal expression of E3 ubiquitin ligase plays an important role in the development and progression of hepatocellular carcinoma (HCC), although the mechanism has remained elusive. This study aimed to investigate the biological function and potential mechanism of FBXO43 in HCC. Methods FBXO43 expression in tissues and cells were detected by quantitative real-time PCR (qRT-PCR), Western blot, and immunohistochemistry (IHC). The Kaplan-Meier method and Cox regression analysis were used to explore the correlation between the expression level of FBXO43 and the clinical survival. MTT assay, EdU incorporation, colony formation, Transwell, and wound healing assays were performed to evaluate the function of FBXO43 in cell proliferation and migration in vitro. The interaction between FBXO43 and cyclin D1 (CCND1) was assessed by co-immunoprecipitation (Co-IP) assay and in vivo ubiquitination assay. Results We found that FBXO43 was upregulated in HCC patient tissues and positively associated with poor clinicopathological features. Meanwhile, HCC patients with high expression of FBXO43 had shorter overall survival (OS) and disease-free survival (DFS). Furthermore, knockdown of FBXO43 inhibited HCC cell proliferation, migration and epithelial-mesenchymal transition (EMT) in HCC cells. Mechanistically, FBXO43 interacted with CCND1 and promoted its stability by polyubiquitination, leading to HCC cell proliferation, migration and EMT. Functional rescue experiments demonstrated that knockdown of CCND1 blocks FBXO43-mediated cell proliferation and metastasis. Conclusions FBXO43, as an independent prognostic biomarker, promotes HCC cell proliferation, metastasis and EMT by stability of CCND1, which provides a new potential strategy for HCC treatment by targeting FBXO43-CCND1 axis.
Collapse
Affiliation(s)
- Chun-Ming Li
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jie Zhang
- Key Laboratory of Hepatobiliary and Pancreatic Surgery, Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Wu Wu
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zhu Zhu
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Feng Li
- Department of Hepatobiliary Surgery, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Di Wu
- Key Laboratory of Hepatobiliary and Pancreatic Surgery, Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xiao-Jun Wang
- Key Laboratory of Hepatobiliary and Pancreatic Surgery, Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- *Correspondence: Jian-Ping Gong, ; Chuan-Ming Xie, ; ; Xiao-Jun Wang,
| | - Chuan-Ming Xie
- Key Laboratory of Hepatobiliary and Pancreatic Surgery, Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- *Correspondence: Jian-Ping Gong, ; Chuan-Ming Xie, ; ; Xiao-Jun Wang,
| | - Jian-Ping Gong
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- *Correspondence: Jian-Ping Gong, ; Chuan-Ming Xie, ; ; Xiao-Jun Wang,
| |
Collapse
|
6
|
The E3 Ubiquitin Ligase Fbxo4 Functions as a Tumor Suppressor: Its Biological Importance and Therapeutic Perspectives. Cancers (Basel) 2022; 14:cancers14092133. [PMID: 35565262 PMCID: PMC9101129 DOI: 10.3390/cancers14092133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 01/10/2023] Open
Abstract
Simple Summary Fbxo4 is an E3 ubiquitin ligase that requires the formation of a complex with S-phase kinase-associated protein 1 and Cullin1 to catalyze the ubiquitylation of its substrates. Moreover, Fbxo4 depends on the existence of posttranslational modifications and/or co-factor to be activated to perform its biological functions. The well-known Fbxo4 substrates have oncogenic or oncogene-like activities, for example, cyclin D1, Trf1/Pin2, p53, Fxr1, Mcl-1, ICAM-1, and PPARγ; therefore, Fbxo4 is defined as a tumor suppressor. Biologically, Fbxo4 regulates cell cycle progression, DNA damage response, tumor metabolism, cellular senescence, metastasis and tumor cells’ response to chemotherapeutic compounds. Clinicopathologically, the expression of Fbxo4 is associated with patients’ prognosis depending on different tumor types. Regarding to its complicated regulation, more in-depth studies are encouraged to dissect the detailed molecular mechanisms to facilitate developing new treatment through targeting Fbxo4. Abstract Fbxo4, also known as Fbx4, belongs to the F-box protein family with a conserved F-box domain. Fbxo4 can form a complex with S-phase kinase-associated protein 1 and Cullin1 to perform its biological functions. Several proteins are identified as Fbxo4 substrates, including cyclin D1, Trf1/Pin2, p53, Fxr1, Mcl-1, ICAM-1, and PPARγ. Those factors can regulate cell cycle progression, cell proliferation, survival/apoptosis, and migration/invasion, highlighting their oncogenic or oncogene-like activities. Therefore, Fbxo4 is defined as a tumor suppressor. The biological functions of Fbxo4 make it a potential candidate for developing new targeted therapies. This review summarizes the gene and protein structure of Fbxo4, the mechanisms of how its expression and activity are regulated, and its substrates, biological functions, and clinicopathological importance in human cancers.
Collapse
|
7
|
Cataldi S, Costa V, Ciccodicola A, Aprile M. PPARγ and Diabetes: Beyond the Genome and Towards Personalized Medicine. Curr Diab Rep 2021; 21:18. [PMID: 33866450 DOI: 10.1007/s11892-021-01385-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/25/2021] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Full and partial synthetic agonists targeting the transcription factor PPARγ are contained in FDA-approved insulin-sensitizing drugs and used for the treatment of metabolic syndrome-related dysfunctions. Here, we discuss the association between PPARG genetic variants and drug efficacy, as well as the role of alternative splicing and post-translational modifications as contributors to the complexity of PPARγ signaling and to the effects of synthetic PPARγ ligands. RECENT FINDINGS PPARγ regulates the transcription of several target genes governing adipocyte differentiation and glucose and lipid metabolism, as well as insulin sensitivity and inflammatory pathways. These pleiotropic functions confer great relevance to PPARγ in physiological regulation of whole-body metabolism, as well as in the etiology of metabolic disorders. Accordingly, PPARG gene mutations, nucleotide variations, and post-translational modifications have been associated with adipose tissue disorders and the related risk of insulin resistance and type 2 diabetes (T2D). Moreover, PPARγ alternative splicing isoforms-generating dominant-negative isoforms mainly expressed in human adipose tissue-have been related to impaired PPARγ activity and adipose tissue dysfunctions. Thus, multiple regulatory levels that contribute to PPARγ signaling complexity may account for the beneficial as well as adverse effects of PPARγ agonists. Further targeted analyses, taking into account all these aspects, are needed for better deciphering the role of PPARγ in human pathophysiology, especially in insulin resistance and T2D. The therapeutic potential of full and partial PPARγ synthetic agonists underlines the clinical significance of this nuclear receptor. PPARG mutations, polymorphisms, alternative splicing isoforms, and post-translational modifications may contribute to the pathogenesis of metabolic disorders, also influencing the responsiveness of pharmacological therapy. Therefore, in the context of the current evidence-based trend to personalized diabetes management, we highlight the need to decipher the intricate regulation of PPARγ signaling to pave the way to tailored therapies in patients with insulin resistance and T2D.
Collapse
Affiliation(s)
- Simona Cataldi
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Via P. Castellino 111, 80131, Naples, Italy
| | - Valerio Costa
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Via P. Castellino 111, 80131, Naples, Italy
| | - Alfredo Ciccodicola
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Via P. Castellino 111, 80131, Naples, Italy.
- Department of Science and Technology, University of Naples "Parthenope", 80131, Naples, Italy.
| | - Marianna Aprile
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Via P. Castellino 111, 80131, Naples, Italy
| |
Collapse
|
8
|
Simoneschi D, Rona G, Zhou N, Jeong YT, Jiang S, Milletti G, Arbini AA, O'Sullivan A, Wang AA, Nithikasem S, Keegan S, Siu Y, Cianfanelli V, Maiani E, Nazio F, Cecconi F, Boccalatte F, Fenyö D, Jones DR, Busino L, Pagano M. CRL4 AMBRA1 is a master regulator of D-type cyclins. Nature 2021; 592:789-793. [PMID: 33854235 DOI: 10.1038/s41586-021-03445-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 03/11/2021] [Indexed: 12/20/2022]
Abstract
D-type cyclins are central regulators of the cell division cycle and are among the most frequently deregulated therapeutic targets in human cancer1, but the mechanisms that regulate their turnover are still being debated2,3. Here, by combining biochemical and genetics studies in somatic cells, we identify CRL4AMBRA1 (also known as CRL4DCAF3) as the ubiquitin ligase that targets all three D-type cyclins for degradation. During development, loss of Ambra1 induces the accumulation of D-type cyclins and retinoblastoma (RB) hyperphosphorylation and hyperproliferation, and results in defects of the nervous system that are reduced by treating pregnant mice with the FDA-approved CDK4 and CDK6 (CDK4/6) inhibitor abemaciclib. Moreover, AMBRA1 acts as a tumour suppressor in mouse models and low AMBRA1 mRNA levels are predictive of poor survival in cancer patients. Cancer hotspot mutations in D-type cyclins abrogate their binding to AMBRA1 and induce their stabilization. Finally, a whole-genome, CRISPR-Cas9 screen identified AMBRA1 as a regulator of the response to CDK4/6 inhibition. Loss of AMBRA1 reduces sensitivity to CDK4/6 inhibitors by promoting the formation of complexes of D-type cyclins with CDK2. Collectively, our results reveal the molecular mechanism that controls the stability of D-type cyclins during cell-cycle progression, in development and in human cancer, and implicate AMBRA1 as a critical regulator of the RB pathway.
Collapse
Affiliation(s)
- Daniele Simoneschi
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Gergely Rona
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA.,Howard Hughes Medical Institute, NYU Grossman School of Medicine, New York, NY, USA
| | - Nan Zhou
- Department of Cancer Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Yeon-Tae Jeong
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Shaowen Jiang
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Giacomo Milletti
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Arnaldo A Arbini
- Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA.,Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - Alfie O'Sullivan
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Andrew A Wang
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Sorasicha Nithikasem
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Sarah Keegan
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA.,Institute for Systems Genetics, NYU Grossman School of Medicine, New York, NY, USA
| | - Yik Siu
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA
| | - Valentina Cianfanelli
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Cell Stress and Survival Unit, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Emiliano Maiani
- Cell Stress and Survival Unit, Danish Cancer Society Research Center, Copenhagen, Denmark.,Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Francesca Nazio
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Francesco Cecconi
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy.,Cell Stress and Survival Unit, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Francesco Boccalatte
- Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA.,Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - David Fenyö
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA.,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA.,Institute for Systems Genetics, NYU Grossman School of Medicine, New York, NY, USA
| | - Drew R Jones
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA
| | - Luca Busino
- Department of Cancer Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
| | - Michele Pagano
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA. .,Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA. .,Howard Hughes Medical Institute, NYU Grossman School of Medicine, New York, NY, USA.
| |
Collapse
|
9
|
Islam S, Dutta P, Chopra K, Rapole S, Chauhan R, Santra MK. FBXW8 regulates G1 and S phases of cell cycle progression by restricting β-TrCP1 function. FEBS J 2021; 288:5474-5497. [PMID: 33742524 DOI: 10.1111/febs.15828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/21/2021] [Accepted: 03/18/2021] [Indexed: 11/30/2022]
Abstract
Sequential alteration in the expression levels of cell cycle regulatory proteins is crucial for faithful cell cycle progression to maintain the cellular homeostasis. F-box protein β-TrCP1 is known to control the expression levels of several important cell cycle regulatory proteins. However, how the function of β-TrCP1 is regulated in spatiotemporal manner during cell cycle progression remains elusive. Here, we show that expression levels of β-TrCP1 oscillate during cell cycle progression with a minimum level at the G1 and S phases of cell cycle. Using biochemical, flow cytometry, and immunofluorescence techniques, we found that oscillation of β-TrCP1 expression is controlled by another F-box protein FBXW8. FBXW8 directs the proteasomal degradation of β-TrCP1 in MAPK pathway-dependent manner. Interestingly, we found that the attenuation of β-TrCP1 by FBXW8 is important for Cdc25A-mediated cell cycle transition from G1 phase to S phase as well as DNA damage-free progression of S phase. Overall, our study reveals the intriguing molecular mechanism and significance of maintenance of β-TrCP1 levels during cell cycle progression by FBXW8-mediated proteasomal degradation.
Collapse
Affiliation(s)
- Sehbanul Islam
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, India.,Department of Biotechnology, Savitribai Phule Pune University, India
| | - Parul Dutta
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, India.,Department of Biotechnology, Savitribai Phule Pune University, India
| | - Kriti Chopra
- Laboratory of Structural Biology, National Centre for Cell Science, Pune, India
| | - Srikanth Rapole
- Proteomics Laboratory, National Centre for Cell Science, Pune, India
| | - Radha Chauhan
- Laboratory of Structural Biology, National Centre for Cell Science, Pune, India
| | - Manas Kumar Santra
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, India
| |
Collapse
|
10
|
Bi Y, Cui D, Xiong X, Zhao Y. The characteristics and roles of β-TrCP1/2 in carcinogenesis. FEBS J 2020; 288:3351-3374. [PMID: 33021036 DOI: 10.1111/febs.15585] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/02/2020] [Accepted: 10/01/2020] [Indexed: 12/11/2022]
Abstract
β-transducin repeat-containing protein (β-TrCP), one of the well-characterized F-box proteins, acts as a substrate receptor and constitutes an active SCFβ-TrCP E3 ligase with a scaffold protein CUL1, a RING protein RBX1, and an adaptor protein SKP1. β-TrCP plays a critical role in the regulation of various physiological and pathological processes, including signal transduction, cell cycle progression, cell migration, DNA damage response, and tumorigenesis, by governing burgeoning amounts of key regulators for ubiquitination and proteasomal degradation. Given that a variety of β-TrCP substrates are well-known oncoproteins and tumor suppressors, and dysregulation of β-TrCP is frequently identified in human cancers, β-TrCP plays a vital role in carcinogenesis. In this review, we first briefly introduce the characteristics of β-TrCP1, β-TrCP2, and SCFβ-TrCP ubiquitin ligase, and then discuss SCFβ-TrCP ubiquitin ligase regulated biological processes by targeting its substrates for degradation. Moreover, we summarize the regulation of β-TrCP1 and β-TrCP2 at multiple layers and further discuss the various roles of β-TrCP1 and β-TrCP2 in human cancer, functioning as either an oncoprotein or a tumor suppressor in a manner dependent of cellular context. Finally, we provide novel insights for future perspectives on the potential of targeting β-TrCP1 and β-TrCP2 for cancer therapy.
Collapse
Affiliation(s)
- Yanli Bi
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Danrui Cui
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiufang Xiong
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China.,Cancer Institute of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yongchao Zhao
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
11
|
Jang SM, Redon CE, Thakur BL, Bahta MK, Aladjem MI. Regulation of cell cycle drivers by Cullin-RING ubiquitin ligases. Exp Mol Med 2020; 52:1637-1651. [PMID: 33005013 PMCID: PMC8080560 DOI: 10.1038/s12276-020-00508-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/10/2020] [Indexed: 12/11/2022] Open
Abstract
The last decade has revealed new roles for Cullin-RING ubiquitin ligases (CRLs) in a myriad of cellular processes, including cell cycle progression. In addition to CRL1, also named SCF (SKP1-Cullin 1-F box protein), which has been known for decades as an important factor in the regulation of the cell cycle, it is now evident that all eight CRL family members are involved in the intricate cellular pathways driving cell cycle progression. In this review, we summarize the structure of CRLs and their functions in driving the cell cycle. We focus on how CRLs target key proteins for degradation or otherwise alter their functions to control the progression over the various cell cycle phases leading to cell division. We also summarize how CRLs and the anaphase-promoting complex/cyclosome (APC/C) ligase complex closely cooperate to govern efficient cell cycle progression.
Collapse
Affiliation(s)
- Sang-Min Jang
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892-4255, USA.
| | - Christophe E Redon
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892-4255, USA
| | - Bhushan L Thakur
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892-4255, USA
| | - Meriam K Bahta
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892-4255, USA
| | - Mirit I Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, 20892-4255, USA.
| |
Collapse
|
12
|
Yumimoto K, Yamauchi Y, Nakayama KI. F-Box Proteins and Cancer. Cancers (Basel) 2020; 12:cancers12051249. [PMID: 32429232 PMCID: PMC7281081 DOI: 10.3390/cancers12051249] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/20/2022] Open
Abstract
Controlled protein degradation is essential for the operation of a variety of cellular processes including cell division, growth, and differentiation. Identification of the relations between ubiquitin ligases and their substrates is key to understanding the molecular basis of cancer development and to the discovery of novel targets for cancer therapeutics. F-box proteins function as the substrate recognition subunits of S-phase kinase-associated protein 1 (SKP1)−Cullin1 (CUL1)−F-box protein (SCF) ubiquitin ligase complexes. Here, we summarize the roles of specific F-box proteins that have been shown to function as tumor promoters or suppressors. We also highlight proto-oncoproteins that are targeted for ubiquitylation by multiple F-box proteins, and discuss how these F-box proteins are deployed to regulate their cognate substrates in various situations.
Collapse
|
13
|
Cyclin D degradation by E3 ligases in cancer progression and treatment. Semin Cancer Biol 2020; 67:159-170. [PMID: 32006569 DOI: 10.1016/j.semcancer.2020.01.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/20/2020] [Accepted: 01/27/2020] [Indexed: 12/15/2022]
Abstract
D cyclins include three isoforms: D1, D2, and D3. D cyclins heterodimerize with cyclin-dependent kinase 4/6 (CDK4/6) to form kinase complexes that can phosphorylate and inactivate Rb. Inactivation of Rb triggers the activation of E2F transcription factors, which in turn regulate the expression of genes whose products drive cell cycle progression. Because D-type cyclins function as mitogenic sensors that link growth factor signaling directly with G1 phase progression, it is not surprising that D cyclin accumulation is dysregulated in a variety of human tumors. Elevated expression of D cyclins results from gene amplification, increased gene transcription and protein translation, decreased microRNA levels, and inefficiency or loss of ubiquitylation-mediated protein degradation. This review focuses on the clinicopathological importance of D cyclins, how dysregulation of Ubiquitin-Proteasome System (UPS) contributes to the overexpression of D cyclins, and the therapeutic potential through targeting D cyclin-related machinery in human tumors.
Collapse
|
14
|
Liu J, Peng Y, Zhang J, Long J, Liu J, Wei W. Targeting SCF E3 Ligases for Cancer Therapies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1217:123-146. [PMID: 31898226 DOI: 10.1007/978-981-15-1025-0_9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
SKP1-cullin-1-F-box-protein (SCF) E3 ubiquitin ligase complex is responsible for the degradation of proteins in a strictly regulated manner, through which it exerts pivotal roles in regulating various key cellular processes including cell cycle and division, apoptosis, and differentiation. The substrate specificity of the SCF complex largely depends on the distinct F-box proteins, which function in either tumor promotion or suppression or in a context-dependent manner. Among the 69 F-box proteins identified in human genome, FBW7, SKP2, and β-TRCP have been extensively investigated among various types of cancer in respective of their roles in cancer development, progression, and metastasis. Moreover, several specific inhibitors have been developed to target those E3 ligases, and their efficiency in tumors has been determined. In this review, we provide a summary of the roles of SCF E3 ligases in cancer development, as well as the potential application of miRNA or specific inhibitors for cancer therapy.
Collapse
Affiliation(s)
- Jing Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yunhua Peng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China.,Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jinfang Zhang
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jiangang Long
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
15
|
Di Sante G, Pagé J, Jiao X, Nawab O, Cristofanilli M, Skordalakes E, Pestell RG. Recent advances with cyclin-dependent kinase inhibitors: therapeutic agents for breast cancer and their role in immuno-oncology. Expert Rev Anticancer Ther 2019; 19:569-587. [PMID: 31219365 PMCID: PMC6834352 DOI: 10.1080/14737140.2019.1615889] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/03/2019] [Indexed: 12/18/2022]
Abstract
Introduction: Collaborative interactions between several diverse biological processes govern the onset and progression of breast cancer. These processes include alterations in cellular metabolism, anti-tumor immune responses, DNA damage repair, proliferation, anti-apoptotic signals, autophagy, epithelial-mesenchymal transition, components of the non-coding genome or onco-mIRs, cancer stem cells and cellular invasiveness. The last two decades have revealed that each of these processes are also directly regulated by a component of the cell cycle apparatus, cyclin D1. Area covered: The current review is provided to update recent developments in the clinical application of cyclin/CDK inhibitors to breast cancer with a focus on the anti-tumor immune response. Expert opinion: The cyclin D1 gene encodes the regulatory subunit of a proline-directed serine-threonine kinase that phosphorylates several substrates. CDKs possess phosphorylation site selectivity, with the phosphate-acceptor residue preceding a proline. Several important proteins are substrates including all three retinoblastoma proteins, NRF1, GCN5, and FOXM1. Over 280 cyclin D3/CDK6 substrates have b\een identified. Given the diversity of substrates for cyclin/CDKs, and the altered thresholds for substrate phosphorylation that occurs during the cell cycle, it is exciting that small molecular inhibitors targeting cyclin D/CDK activity have encouraging results in specific tumors.
Collapse
Affiliation(s)
- Gabriele Di Sante
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center, Wynnewood, PA, USA
| | - Jessica Pagé
- Xavier University School of Medicine, Woodbury, NY, USA
| | - Xuanmao Jiao
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center, Wynnewood, PA, USA
| | - Omar Nawab
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center, Wynnewood, PA, USA
- Xavier University School of Medicine, Woodbury, NY, USA
| | - Massimo Cristofanilli
- Department of Medicine-Hematology and Oncology, Robert H Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Richard G Pestell
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center, Wynnewood, PA, USA
- Xavier University School of Medicine, Woodbury, NY, USA
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| |
Collapse
|
16
|
Ma Y, Cui D, Xiong X, Inuzuka H, Wei W, Sun Y, North BJ, Zhao Y. SCFβ-TrCP ubiquitinates CHK1 in an AMPK-dependent manner in response to glucose deprivation. Mol Oncol 2018; 13:307-321. [PMID: 30428154 PMCID: PMC6360357 DOI: 10.1002/1878-0261.12403] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 09/17/2018] [Accepted: 10/15/2018] [Indexed: 12/15/2022] Open
Abstract
The ATR/CHK1 pathway is a key effector of cellular response to DNA damage and therefore is a critical regulator of genomic stability. While the ATR/CHK1 pathway is often inactivated by mutations, CHK1 itself is rarely mutated in human cancers. Thus, cellular levels of CHK1 likely play a key role in the maintenance of genomic stability and preventing tumorigenesis. Glucose deprivation is observed in many solid tumors due to high glycolytic rates of cancer cells and insufficient vascularization, yet cancer cells have devised mechanisms to survive in conditions of low glucose. Although CHK1 degradation through the ubiquitin-proteasome pathway following glucose deprivation has been previously reported, the detailed molecular mechanisms remain elusive. Here, we show that CHK1 is ubiquitinated and degraded upon glucose deprivation by the Skp1-Cullin-F-box (β-TrCP) E3 ubiquitin ligase. Specifically, CHK1 contains a β-TrCP recognizable degron domain, which is phosphorylated by AMPK in response to glucose deprivation, allowing for β-TrCP to recognize CHK1 for subsequent ubiquitination and degradation. Our results provide a novel mechanism by which glucose metabolism regulates a DNA damage effector, and imply that glucose deprivation, which is often found in solid tumor microenvironments, may enhance mutagenesis, clonal expansion, and tumor progression by triggering CHK1 degradation.
Collapse
Affiliation(s)
- Ying Ma
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China.,Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Danrui Cui
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiufang Xiong
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Center for Advanced Stem Cell and Regenerative Research, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Yi Sun
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China.,Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Brian J North
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Yongchao Zhao
- Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
17
|
Jang SM, Redon CE, Aladjem MI. Chromatin-Bound Cullin-Ring Ligases: Regulatory Roles in DNA Replication and Potential Targeting for Cancer Therapy. Front Mol Biosci 2018; 5:19. [PMID: 29594129 PMCID: PMC5859106 DOI: 10.3389/fmolb.2018.00019] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/12/2018] [Indexed: 12/14/2022] Open
Abstract
Cullin-RING (Really Interesting New Gene) E3 ubiquitin ligases (CRLs), the largest family of E3 ubiquitin ligases, are functional multi-subunit complexes including substrate receptors, adaptors, cullin scaffolds, and RING-box proteins. CRLs are responsible for ubiquitination of ~20% of cellular proteins and are involved in diverse biological processes including cell cycle progression, genome stability, and oncogenesis. Not surprisingly, cullins are deregulated in many diseases and instances of cancer. Recent studies have highlighted the importance of CRL-mediated ubiquitination in the regulation of DNA replication/repair, including specific roles in chromatin assembly and disassembly of the replication machinery. The development of novel therapeutics targeting the CRLs that regulate the replication machinery and chromatin in cancer is now an attractive therapeutic strategy. In this review, we summarize the structure and assembly of CRLs and outline their cellular functions and their diverse roles in cancer, emphasizing the regulatory functions of nuclear CRLs in modulating the DNA replication machinery. Finally, we discuss the current strategies for targeting CRLs against cancer in the clinic.
Collapse
Affiliation(s)
| | | | - Mirit I. Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States
| |
Collapse
|
18
|
Ben Younes K, Body S, Costé É, Viailly PJ, Miloudi H, Coudre C, Jardin F, Ben Aissa-Fennira F, Sola B. A lowered 26S proteasome activity correlates with mantle lymphoma cell lines resistance to genotoxic stress. BMC Cancer 2017; 17:538. [PMID: 28797244 PMCID: PMC5553741 DOI: 10.1186/s12885-017-3530-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 08/03/2017] [Indexed: 01/04/2023] Open
Abstract
Background Mantle cell lymphoma (MCL) is a B-cell hemopathy characterized by the t(11;14) translocation and the aberrant overexpression of cyclin D1. This results in an unrestrained cell proliferation. Other genetic alterations are common in MCL cells such as SOX11 expression, mutations of ATM and/or TP53 genes, activation of the NF-κB signaling pathway and NOTCH receptors. These alterations lead to the deregulation of the apoptotic machinery and resistance to drugs. We observed that among a panel of MCL cell lines, REC1 cells were resistant towards genotoxic stress. We studied the molecular basis of this resistance. Methods We analyzed the cell response regarding apoptosis, senescence, cell cycle arrest, DNA damage response and finally the 26S proteasome activity following a genotoxic treatment that causes double strand DNA breaks. Results MCL cell lines displayed various sensitivity/resistance towards genotoxic stress and, in particular, REC1 cells did not enter apoptosis or senescence after an etoposide treatment. Moreover, the G2/M cell cycle checkpoint was deficient in REC1 cells. We observed that three main actors of apoptosis, senescence and cell cycle regulation (cyclin D1, MCL1 and CDC25A) failed to be degraded by the proteasome machinery in REC1 cells. We ruled out a default of the βTrCP E3-ubiquitine ligase but detected a lowered 26S proteasome activity in REC1 cells compared to other cell lines. Conclusion The resistance of MCL cells to genotoxic stress correlates with a low 26S proteasome activity. This could represent a relevant biomarker for a subtype of MCL patients with a poor response to therapies and a high risk of relapse. Electronic supplementary material The online version of this article (doi:10.1186/s12885-017-3530-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Khaoula Ben Younes
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France.,Faculté de médecine, Laboratoire de Génétique, d'Immunologie et de Pathologie humaines, Université de Tunis El Manar, Tunis, Tunisia
| | - Simon Body
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France
| | - Élodie Costé
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France
| | - Pierre-Julien Viailly
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France.,Département d'Hématologie Clinique, Centre de Lutte contre le Cancer Henri Becquerel, Rouen, France
| | - Hadjer Miloudi
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France
| | - Clémence Coudre
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France
| | - Fabrice Jardin
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France.,Département d'Hématologie Clinique, Centre de Lutte contre le Cancer Henri Becquerel, Rouen, France
| | - Fatma Ben Aissa-Fennira
- Faculté de médecine, Laboratoire de Génétique, d'Immunologie et de Pathologie humaines, Université de Tunis El Manar, Tunis, Tunisia
| | - Brigitte Sola
- Normandie Univ, INSERM UMR 1245, UNIROUEN, UNICAEN, Caen, France. .,MICAH, UFR Santé, CHU Côte de Nacre, 14032, Caen Cedex, France.
| |
Collapse
|
19
|
Liu Q, Tang Y, Chen L, Liu N, Lang F, Liu H, Wang P, Sun X. E3 Ligase SCFβTrCP-induced DYRK1A Protein Degradation Is Essential for Cell Cycle Progression in HEK293 Cells. J Biol Chem 2016; 291:26399-26409. [PMID: 27807027 PMCID: PMC5159501 DOI: 10.1074/jbc.m116.717553] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 11/01/2016] [Indexed: 11/29/2022] Open
Abstract
DYRK1A, located on the Down syndrome (DS) critical region of chromosome 21, was found to be overexpressed in brains of DS and Alzheimer's disease individuals. DYRK1A was considered to play important roles in the pathogenesis of DS and Alzheimer's disease; however, the degradation mechanism of DYRK1A was still unclear. In this study, we found that DYRK1A was degraded through the ubiquitin-proteasome pathway in HEK293 cells. The N terminus of DYRK1A that was highly unstable in HEK293 cells contributed to proteolysis of DYRK1A. E3 ligase SCFβTrCP mediated ubiquitination and promoted degradation of DYRK1A through an unconserved binding motif (49SDQQVSALS57) lying in the N terminus. Any Ser-Ala substitution in this motif could decrease the binding between DYRK1A and β-transducin repeat containing protein (βTrCP), resulting in stabilization of DYRK1A. We also found DYRK1A protein was elevated in the G0/G1 phase and decreased in the S and G2/M phase, which was negatively correlated to βTrCP levels in the HEK293 cell cycle. Knockdown of βTrCP caused arrest of the G0/G1 phase, which could be partly rescued by down-regulation of DYRK1A. Our study uncovered a new regulatory mechanism of DYRK1A degradation by SCFβTrCP in HEK293 cell cycle progression.
Collapse
Affiliation(s)
- Qiang Liu
- From the Brain Research Institute
- the Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, 10766 Jingshi Road, Jinan 250014, and
| | | | - Long Chen
- National Key Lab of Otolaryngology, and
| | - Na Liu
- Department of Hematology, Qilu Hospital of Shandong University, Jinan 250012
| | - Fangfang Lang
- the Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated with Shandong University, 105 Jiefang Road, Jinan 250013, China
| | - Heng Liu
- National Key Lab of Otolaryngology, and
| | - Pin Wang
- National Key Lab of Otolaryngology, and
| | - Xiulian Sun
- From the Brain Research Institute,
- National Key Lab of Otolaryngology, and
| |
Collapse
|
20
|
Qie S, Diehl JA. Cyclin D1, cancer progression, and opportunities in cancer treatment. J Mol Med (Berl) 2016; 94:1313-1326. [PMID: 27695879 PMCID: PMC5145738 DOI: 10.1007/s00109-016-1475-3] [Citation(s) in RCA: 445] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/06/2016] [Accepted: 09/13/2016] [Indexed: 12/15/2022]
Abstract
Mammalian cells encode three D cyclins (D1, D2, and D3) that coordinately function as allosteric regulators of cyclin-dependent kinase 4 (CDK4) and CDK6 to regulate cell cycle transition from G1 to S phase. Cyclin expression, accumulation, and degradation, as well as assembly and activation of CDK4/CDK6 are governed by growth factor stimulation. Cyclin D1 is more frequently dysregulated than cyclin D2 or D3 in human cancers, and as such, it has been more extensively characterized. Overexpression of cyclin D1 results in dysregulated CDK activity, rapid cell growth under conditions of restricted mitogenic signaling, bypass of key cellular checkpoints, and ultimately, neoplastic growth. This review discusses cyclin D1 transcriptional, translational, and post-translational regulations and its biological function with a particular focus on the mechanisms that result in its dysregulation in human cancers.
Collapse
Affiliation(s)
- Shuo Qie
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St, Charleston, SC, 29425, USA
| | - J Alan Diehl
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St, Charleston, SC, 29425, USA.
| |
Collapse
|
21
|
Berberine Suppresses Cyclin D1 Expression through Proteasomal Degradation in Human Hepatoma Cells. Int J Mol Sci 2016; 17:ijms17111899. [PMID: 27854312 PMCID: PMC5133898 DOI: 10.3390/ijms17111899] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/04/2016] [Accepted: 11/09/2016] [Indexed: 12/20/2022] Open
Abstract
The aim of this study is to explore the underlying mechanism on berberine-induced Cyclin D1 degradation in human hepatic carcinoma. We observed that berberine could suppress both in vitro and in vivo expression of Cyclin D1 in hepatoma cells. Berberine exhibits dose- and time-dependent inhibition on Cyclin D1 expression in human hepatoma cell HepG2. Berberine increases the phosphorylation of Cyclin D1 at Thr286 site and potentiates Cyclin D1 nuclear export to cytoplasm for proteasomal degradation. In addition, berberine recruits the Skp, Cullin, F-box containing complex-β-Transducin Repeat Containing Protein (SCFβ-TrCP) complex to facilitate Cyclin D1 ubiquitin-proteasome dependent proteolysis. Knockdown of β-TrCP blocks Cyclin D1 turnover induced by berberine; blocking the protein degradation induced by berberine in HepG2 cells increases tumor cell resistance to berberine. Our results shed light on berberine′s potential as an anti-tumor agent for clinical cancer therapy.
Collapse
|
22
|
Berthe A, Flament S, Grandemange S, Zaffino M, Boisbrun M, Mazerbourg S. Δ2-Troglitazone promotes cytostatic rather than pro-apoptotic effects in breast cancer cells cultured in high serum conditions. Cell Cycle 2016; 15:3402-3412. [PMID: 27753533 DOI: 10.1080/15384101.2016.1245248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have previously shown that Δ2-Troglitazone (Δ2-TGZ) displayed anticancer effects on breast cancer cell lines grown in low serum conditions (1% fetal calf serum (FCS)). The present study was performed in order to characterize the effects of Δ2-TGZ in high serum containing medium and to determine if starvation could influence the response of breast cancer cells to this compound, keeping in mind the potential interest for breast cancer therapy. We observed that in high serum conditions (10% FCS), a 48 h treatment with Δ2-TGZ induced a decrease in cell numbers in MDA-MB-231 and MCF-7 breast cancer cell lines. The IC50 values were higher than in low serum conditions. Furthermore, in contrast to our previous results obtained in 1% FCS conditions, we observed that in 10% FCS-containing medium, MCF-7 cells were more sensitive to Δ2-TGZ than MDA-MB-231 cells. Δ2-TGZ also induced endoplasmic reticulum (ER) stress mainly in MDA-MB-231 cells. Besides, in high serum conditions, Δ2-TGZ induced a G0/G1 cell cycle arrest, an inhibition of BrdU incorporation and a reduced level of cyclin D1. We observed a limited cleavage of PARP and a limited proportion of cells in sub-G1 phase. Thus, in high serum conditions, Δ2-TGZ displayed cytostatic effects rather than apoptosis as previously reported in 1% FCS-containing medium. Our results are in accordance with studies suggesting that serum starvation could potentiate the action of diverse anti-cancer agents.
Collapse
Affiliation(s)
- Audrey Berthe
- a Université de Lorraine, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France.,b CNRS, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France
| | - Stéphane Flament
- a Université de Lorraine, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France.,b CNRS, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France
| | - Stéphanie Grandemange
- a Université de Lorraine, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France.,b CNRS, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France
| | - Marie Zaffino
- a Université de Lorraine, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France.,b CNRS, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France
| | - Michel Boisbrun
- c Université de Lorraine, SRSMC , UMR 7565, Vandœuvre-lès-Nancy , France.,d CNRS, SRSMC , UMR 7565, Vandœuvre-lès-Nancy , France
| | - Sabine Mazerbourg
- a Université de Lorraine, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France.,b CNRS, CRAN , UMR 7039, Vandœuvre-lès-Nancy , France
| |
Collapse
|
23
|
Santha S, Davaakhuu G, Basu A, Ke R, Das S, Rana A, Rana B. Modulation of glycogen synthase kinase-3β following TRAIL combinatorial treatment in cancer cells. Oncotarget 2016; 7:66892-66905. [PMID: 27602497 PMCID: PMC5341845 DOI: 10.18632/oncotarget.11834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 08/29/2016] [Indexed: 12/12/2022] Open
Abstract
Glycogen Synthase Kinase-3β (GSK3β) is a serine/threonine kinase, known to regulate various cellular processes including proliferation, differentiation, survival, apoptosis as well as TRAIL-resistance. Thus pathways that can modulate GSK3β axis are important targets for cancer drug development. Our earlier studies have shown that combinatorial treatment with Troglitazone (TZD) and TRAIL can induce apoptosis in TRAIL-resistant cancer cells. The current studies were undertaken to investigate whether GSK3β pathway was modulated during this apoptosis. Our results indicated an increase in inhibitory GSK3βSer9 phosphorylation during apoptosis, mediated via AKT. At a later time, however, TZD alone and TRAIL-TZD combination produced a dramatic reduction of GSK3β expression, which was abolished by cycloheximide. Luciferase assays with GSK3β-luc promoter reporter showed that TZD can effectively antagonize GSK3β promoter activity. Since TZD is a ligand for transcription factor PPARγ and can activate AMPK, we determined their roles on antagonism of GSK3β. Knockdown of PPARγ was unable to restore GSK3β expression or antagonize GSK3βSer9 phosphorylation. Although pretreatment with Compound C (pharmacological inhibitor of AMPK) partially rescued GSK3β expression, knockdown of AMPKα1 or α2 alone or in combination were ineffective. These studies suggested a novel PPARγ-AMPK-independent mechanism of targeting GSK3β by TZD, elucidation of which might provide newer insights to improve our understanding of TRAIL-resistance.
Collapse
Affiliation(s)
- Sreevidya Santha
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Gantulga Davaakhuu
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Aninda Basu
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Rong Ke
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Subhasis Das
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Ajay Rana
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA.,University of Illinois Hospital and Health Sciences System Cancer Center, University of Illinois at Chicago, Chicago, IL 60612, USA.,Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - Basabi Rana
- Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA.,University of Illinois Hospital and Health Sciences System Cancer Center, University of Illinois at Chicago, Chicago, IL 60612, USA.,Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| |
Collapse
|
24
|
Shrestha H, Yuan T, He Y, Moon PG, Shrestha N, Ryu T, Park SY, Cho YC, Lee CH, Baek MC, Cho S, Simkhada S, Kim H, Kim K. Investigation of the molecular mechanism of δ-catenin ubiquitination: Implication of β-TrCP-1 as a potential E3 ligase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2311-21. [PMID: 27316454 DOI: 10.1016/j.bbamcr.2016.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 05/30/2016] [Accepted: 06/10/2016] [Indexed: 12/17/2022]
Abstract
Ubiquitination, a post-translational modification, involves the covalent attachment of ubiquitin to the target protein. The ubiquitin-proteasome pathway and the endosome-lysosome pathway control the degradation of the majority of eukaryotic proteins. Our previous study illustrated that δ-catenin ubiquitination occurs in a glycogen synthase kinase-3 (GSK-3) phosphorylation-dependent manner. However, the molecular mechanism of δ-catenin ubiquitination is still unknown. Here, we show that the lysine residues required for ubiquitination are located mainly in the C-terminal portion of δ-catenin. In addition, we provide evidence that β-TrCP-1 interacts with δ-catenin and functions as an E3 ligase, mediating δ-catenin ubiquitin-proteasome degradation. Furthermore, we prove that both the ubiquitin-proteasome pathway and the lysosome degradation pathway are involved in δ-catenin degradation. Our novel findings on the mechanism of δ-catenin ubiquitination will add a new perspective to δ-catenin degradation and the effects of δ-catenin on E-cadherin involved in epithelial cell-cell adhesion, which is implicated in prostate cancer progression.
Collapse
Affiliation(s)
- Hridaya Shrestha
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Tingting Yuan
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Yongfeng He
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Pyong-Gon Moon
- Department of Molecular Medicine, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Nensi Shrestha
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Taeyong Ryu
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - So-Yeon Park
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 540-950, Republic of Korea
| | - Young-Chang Cho
- College of Pharmacy, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - Chan-Hyeong Lee
- Department of Molecular Medicine, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Moon-Chang Baek
- Department of Molecular Medicine, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Sayeon Cho
- College of Pharmacy, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - Shishli Simkhada
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Hangun Kim
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 540-950, Republic of Korea
| | - Kwonseop Kim
- College of Pharmacy and Research Institute for Drug Development, Chonnam National University, Gwangju 500-757, Republic of Korea
| |
Collapse
|
25
|
Zheng N, Zhou Q, Wang Z, Wei W. Recent advances in SCF ubiquitin ligase complex: Clinical implications. Biochim Biophys Acta Rev Cancer 2016; 1866:12-22. [PMID: 27156687 DOI: 10.1016/j.bbcan.2016.05.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/09/2022]
Abstract
F-box proteins, which are subunit recruiting modules of SCF (SKP1-Cullin 1-F-box protein) E3 ligase complexes, play critical roles in the development and progression of human malignancies through governing multiple cellular processes including cell proliferation, apoptosis, invasion and metastasis. Moreover, there are emerging studies that lead to the development of F-box proteins inhibitors with promising therapeutic potential. In this article, we describe how F-box proteins including but not restricted to well-established Fbw7, Skp2 and β-TRCP, are involved in tumorigenesis. However, in-depth investigation is required to further explore the mechanism and the physiological contribution of undetermined F-box proteins in carcinogenesis. Lastly, we suggest that targeting F-box proteins could possibly open new avenues for the treatment and prevention of human cancers.
Collapse
Affiliation(s)
- Nana Zheng
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Quansheng Zhou
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Zhiwei Wang
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China; Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA 02215, USA.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA 02215, USA.
| |
Collapse
|
26
|
Zheng N, Wang Z, Wei W. Ubiquitination-mediated degradation of cell cycle-related proteins by F-box proteins. Int J Biochem Cell Biol 2016; 73:99-110. [PMID: 26860958 PMCID: PMC4798898 DOI: 10.1016/j.biocel.2016.02.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 02/06/2023]
Abstract
F-box proteins, subunits of SKP1-cullin 1-F-box protein (SCF) type of E3 ubiquitin ligase complexes, have been validated to play a crucial role in governing various cellular processes such as cell cycle, cell proliferation, apoptosis, migration, invasion and metastasis. Recently, a wealth of evidence has emerged that F-box proteins is critically involved in tumorigenesis in part through governing the ubiquitination and subsequent degradation of cell cycle proteins, and dysregulation of this process leads to aberrant cell cycle progression and ultimately, tumorigenesis. Therefore, in this review, we describe the critical role of F-box proteins in the timely regulation of cell cycle. Moreover, we discuss how F-box proteins involve in tumorigenesis via targeting cell cycle-related proteins using biochemistry studies, engineered mouse models, and pathological gene alternations. We conclude that inhibitors of F-box proteins could have promising therapeutic potentials in part through controlling of aberrant cell cycle progression for cancer therapies.
Collapse
Affiliation(s)
- Nana Zheng
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, The First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Zhiwei Wang
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, The First Affiliated Hospital, Soochow University, Suzhou 215123, China; Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, USA.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, USA.
| |
Collapse
|
27
|
Wu W, Zhang D, Pan D, Zuo G, Ren X, Chen S. Downregulation of vascular endothelial growth factor receptor-2 under oxidative stress conditions is mediated by β-transduction repeat-containing protein via glycogen synthase kinase-3β signaling. Int J Mol Med 2016; 37:911-20. [PMID: 26935904 PMCID: PMC4790698 DOI: 10.3892/ijmm.2016.2493] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/05/2016] [Indexed: 12/22/2022] Open
Abstract
Vascular endothelial growth factor receptor-2 (VEGFR-2), which is a key determinant of the angiogenecic response, is decreased in diabetic mice under oxidative stress. β-transduction repeat-containing protein (β-TrCP) has been reported to participate in VEGFR-2 degradation in thyroid cancer cells. Additionally, glycogen synthase kinase-3β (GSK-3β) acts as a mediator in the β-TrCP-induced degradation of several proteins. However, the role played by β-TrCP and GSK-3β in the degradation of VEGFR-2 in endothelial cells where hyperglycemia had been induced was not fully understood. In the present study, we aimed to analyze the mechanisms of VEGFR-2 degradation by studying excess reactive oxygen species (ROS) induced by hyperglycemia or glucose oxidase (GO). Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of glucose (6.6, 19.8 and 33 mM), mannitol (33 mM) and GO (1 U/ml). Angiogenic function, ROS levels, the co-location of VEGFR-2 and β-TrCP were evaluated. Cells were collected for RT-qPCR and western blot analysis. We noted that angiogenesis was impaired upon increasing the glucose concentration. When HUVECs were in a hyperglycemic state, ROS production increased, comparable to exposure to GO; GO catalyzes oxidation of glucose into H2O2 and D-glucono-δ-lactone. Phosphorylated VEGFR-2 was reduced by hyperglycemia while total VEGFR-2 was almost unaltered. However, VEGFR-2 was reduced when directly exposed to ROS, with resultant co-location of β-TrCP and VEGFR-2. Through a co-immunoprecipitation assay, we noted that ubiquitinated VEGFR-2 was significantly augmented by excess ROS. Decreased VEGFR-2 caused by ROS was ameliorated by β-TrCP siRNA, proteasome inhibitor MG132 and GSK-3β activity inhibitor (lithium chloride and SB216763). We suggest that redundant ROS reduces VEGFR-2 through β-TrCP-mediated VEGFR-2 degradation, which is postulated to be regulated by GSK-3β.
Collapse
Affiliation(s)
- Wen Wu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Qinhuai, Nanjing 210006, P.R. China
| | - Daimin Zhang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Qinhuai, Nanjing 210006, P.R. China
| | - Daorong Pan
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Qinhuai, Nanjing 210006, P.R. China
| | - Guangfeng Zuo
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Qinhuai, Nanjing 210006, P.R. China
| | - Xiaomin Ren
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Qinhuai, Nanjing 210006, P.R. China
| | - Shaoliang Chen
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Qinhuai, Nanjing 210006, P.R. China
| |
Collapse
|
28
|
Vriend J, Reiter RJ. Breast cancer cells: Modulation by melatonin and the ubiquitin-proteasome system--a review. Mol Cell Endocrinol 2015; 417:1-9. [PMID: 26363225 DOI: 10.1016/j.mce.2015.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/01/2015] [Indexed: 02/07/2023]
Abstract
Melatonin inhibits human breast cancer cells stimulated with estrogen. This antiproliferative action depends on the presence of the estrogen receptor alpha (ERα) in the human MCF-7 cell line and is strictly dose-dependent. Since researchers concerned with melatonin and breast cancer have not considered the relevance of the ubiquitin-proteasome system to this research in this review we do so. The fact that the first breast cancer susceptibility gene to be identified, Brca1, functions as a ubiquitin ligase indicates that the ubiquitin-proteasome system has a role in regulating susceptibility to breast cancer. While mutations of this gene increase the incidence of breast cancer, the wild type gene suppresses estrogen-dependent transcriptional events relying on the estrogen receptor ERα. Three other ubiquitin ligases, SCF(Skp2), E6AP and APC, interact directly with ERα at the ERE and AP-1 promoters of ERα target genes. Melatonin, like proteasome inhibitors, decreases estrogen-induced gene transcription. Indeed, it has been reported that melatonin specifically inhibits estrogen-induced transcription mediated by ERα at the ERE and AP1 gene promoters. Herein, we present a model in which the inhibitory action of melatonin on MCF-7 cells is mediated, directly or indirectly, by the ubiquitin-proteasome system. In this model ERα, apoptotic proteins, and cell cycle proteins, all influenced by melatonin, are substrates of key ubiquitin ligases including SCF(Skp2), E6AP, and SCF(B-TrCP). Since dysfunction of the ubiquitin-proteasome system is a risk factor for breast cancer, this model provides a context in which to test the clinical potential, and limitations, of melatonin and proteasome inhibitors.
Collapse
Affiliation(s)
- Jerry Vriend
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada.
| | - Russel J Reiter
- Department of Cellular and Structural Biology, UT Health Science Center San Antonio, TX, USA
| |
Collapse
|
29
|
Randle SJ, Laman H. F-box protein interactions with the hallmark pathways in cancer. Semin Cancer Biol 2015; 36:3-17. [PMID: 26416465 DOI: 10.1016/j.semcancer.2015.09.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 09/18/2015] [Accepted: 09/23/2015] [Indexed: 12/24/2022]
Abstract
F-box proteins (FBP) are the substrate specifying subunit of Skp1-Cul1-FBP (SCF)-type E3 ubiquitin ligases and are responsible for directing the ubiquitination of numerous proteins essential for cellular function. Due to their ability to regulate the expression and activity of oncogenes and tumour suppressor genes, FBPs themselves play important roles in cancer development and progression. In this review, we provide a comprehensive overview of FBPs and their targets in relation to their interaction with the hallmarks of cancer cell biology, including the regulation of proliferation, epigenetics, migration and invasion, metabolism, angiogenesis, cell death and DNA damage responses. Each cancer hallmark is revealed to have multiple FBPs which converge on common signalling hubs or response pathways. We also highlight the complex regulatory interplay between SCF-type ligases and other ubiquitin ligases. We suggest six highly interconnected FBPs affecting multiple cancer hallmarks, which may prove sensible candidates for therapeutic intervention.
Collapse
Affiliation(s)
- Suzanne J Randle
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Heike Laman
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom.
| |
Collapse
|
30
|
Abstract
Among the cell cycle-related mammalian cyclins, cyclin D1 is more closely connected with cell proliferation in response to extracellular signals than the cell cycle clock itself. Because both its mRNA and protein are labile, the intracellular abundance of cyclin D1 is thought to be largely regulated at the level of transcription. However, recent findings suggest that, in certain cell types, cyclin D1 is post-translationally regulated, and a disturbance of this regulatory mechanism induces aberrant entry into the cell cycle and proliferation, sometimes leading to diseases such as cancer. In this review, we summarize recent findings and discuss the physiological role and cellular function of the novel mechanism of regulation of cyclin D1 in terms of the control of cell proliferation.
Collapse
|
31
|
Chou CC, Salunke SB, Kulp SK, Chen CS. Prospects on strategies for therapeutically targeting oncogenic regulatory factors by small-molecule agents. J Cell Biochem 2014; 115:611-24. [PMID: 24166934 DOI: 10.1002/jcb.24704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 10/22/2013] [Indexed: 12/12/2022]
Abstract
Although the Human Genome Project has raised much hope for the identification of druggable genetic targets for cancer and other diseases, this genetic target-based approach has not improved productivity in drug discovery over the traditional approach. Analyses of known human target proteins of currently marketed drugs reveal that these drugs target only a limited number of proteins as compared to the whole proteome. In contrast to genome-based targets, mechanistic targets are derived from empirical research, at cellular or molecular levels, in disease models and/or in patients, thereby enabling the exploration of a greater number of druggable targets beyond the genome and epigenome. The paradigm shift has made a tremendous headway in developing new therapeutic agents targeting different clinically relevant mechanisms/pathways in cancer cells. In this Prospects article, we provide an overview of potential drug targets related to the following four emerging areas: (1) tumor metabolism (the Warburg effect), (2) dysregulated protein turnover (E3 ubiquitin ligases), (3) protein-protein interactions, and (4) unique DNA high-order structures and protein-DNA interactions. Nonetheless, considering the genetic and phenotypic heterogeneities that characterize cancer cells, the development of drug resistance in cancer cells by adapting signaling circuitry to take advantage of redundant pathways or feedback/crosstalk systems is possible. This "phenotypic adaptation" underlies the rationale of using therapeutic combinations of these targeted agents with cytotoxic drugs.
Collapse
Affiliation(s)
- Chih-Chien Chou
- Division of Medicinal Chemistry, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | | | | | | |
Collapse
|
32
|
Kuntz S, Mazerbourg S, Boisbrun M, Cerella C, Diederich M, Grillier-Vuissoz I, Flament S. Energy restriction mimetic agents to target cancer cells: comparison between 2-deoxyglucose and thiazolidinediones. Biochem Pharmacol 2014; 92:102-11. [PMID: 25083915 DOI: 10.1016/j.bcp.2014.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 01/02/2023]
Abstract
The use of energy restriction mimetic agents (ERMAs) to selectively target cancer cells addicted to glycolysis could be a promising therapeutic approach. Thiazolidinediones (TZDs) are synthetic agonists of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)γ that were developed to treat type II diabetes. These compounds also display anticancer effects which appear mainly to be independent of their PPARγ agonist activity but the molecular mechanisms involved in the anticancer action are not yet well understood. Results obtained on ciglitazone derivatives, mainly in prostate cancer cell models, suggest that these compounds could act as ERMAs. In the present paper, we introduce how compounds like 2-deoxyglucose target the Warburg effect and then we discuss the possibility that the PPARγ-independent effects of various TZD could result from their action as ERMAs.
Collapse
Affiliation(s)
- Sandra Kuntz
- Université de Lorraine, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France; CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France
| | - Sabine Mazerbourg
- Université de Lorraine, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France; CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France
| | - Michel Boisbrun
- Université de Lorraine, SRSMC, UMR 7565, Vandœuvre-lès-Nancy, F-54506, France; CNRS, SRSMC, UMR 7565, Vandœuvre-lès-Nancy, F-54506, France
| | - Claudia Cerella
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer. Hôpital Kirchberg, L-2540, Luxembourg
| | - Marc Diederich
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer. Hôpital Kirchberg, L-2540, Luxembourg; Department of Pharmacy, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Isabelle Grillier-Vuissoz
- Université de Lorraine, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France; CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France
| | - Stephane Flament
- Université de Lorraine, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France; CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy, F-54506, France.
| |
Collapse
|
33
|
Liu S, Lin SJ, Li G, Kim E, Chen YT, Yang DR, Tan MHE, Yong EL, Chang C. Differential roles of PPARγ vs TR4 in prostate cancer and metabolic diseases. Endocr Relat Cancer 2014; 21:R279-300. [PMID: 24623743 DOI: 10.1530/erc-13-0529] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ, NR1C3) and testicular receptor 4 nuclear receptor (TR4, NR2C2) are two members of the nuclear receptor (NR) superfamily that can be activated by several similar ligands/activators including polyunsaturated fatty acid metabolites, such as 13-hydroxyoctadecadienoic acid and 15-hydroxyeicosatetraenoic acid, as well as some anti-diabetic drugs such as thiazolidinediones (TZDs). However, the consequences of the transactivation of these ligands/activators via these two NRs are different, with at least three distinct phenotypes. First, activation of PPARγ increases insulin sensitivity yet activation of TR4 decreases insulin sensitivity. Second, PPARγ attenuates atherosclerosis but TR4 might increase the risk of atherosclerosis. Third, PPARγ suppresses prostate cancer (PCa) development and TR4 suppresses prostate carcinogenesis yet promotes PCa metastasis. Importantly, the deregulation of either PPARγ or TR4 in PCa alone might then alter the other receptor's influences on PCa progression. Knocking out PPARγ altered the ability of TR4 to promote prostate carcinogenesis and knocking down TR4 also resulted in TZD treatment promoting PCa development, indicating that both PPARγ and TR4 might coordinate with each other to regulate PCa initiation, and the loss of either one of them might switch the other one from a tumor suppressor to a tumor promoter. These results indicate that further and detailed studies of both receptors at the same time in the same cells/organs may help us to better dissect their distinct physiological roles and develop better drug(s) with fewer side effects to battle PPARγ- and TR4-related diseases including tumor and cardiovascular diseases as well as metabolic disorders.
Collapse
Affiliation(s)
- Su Liu
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Shin-Jen Lin
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Gonghui Li
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Eungseok Kim
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Yei-Tsung Chen
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Dong-Rong Yang
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - M H Eileen Tan
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Eu Leong Yong
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| | - Chawnshang Chang
- George Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, TaiwanGeorge Whipple Laboratory for Cancer ResearchDepartments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USADepartment of Obstetrics and GynecologyNational University of Singapore, Singapore, SingaporeChawnshang Chang Liver Cancer Center and Department of UrologySir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, ChinaDepartment of Biological SciencesChonnam National University, Youngbong, Buk-Gu, Gwangju 500-757 KoreaCardiovascular Research InstituteNational University Health System and The Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeSex Hormone Research CenterChina Medical University/Hospital, Taichung 404, Taiwan
| |
Collapse
|
34
|
Gao C, Chen G, Romero G, Moschos S, Xu X, Hu J. Induction of Gsk3β-β-TrCP interaction is required for late phase stabilization of β-catenin in canonical Wnt signaling. J Biol Chem 2014; 289:7099-7108. [PMID: 24451375 DOI: 10.1074/jbc.m113.532606] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A pivotal step in canonical Wnt signaling is Wnt-induced β-catenin stabilization. In the absence of Wnt, β-catenin is targeted for β-transducin repeats-containing proteins (β-TrCP)-mediated degradation due to phosphorylation by glycogen synthase kinase 3 (Gsk3). How canonical Wnt signaling regulates Gsk3 to inhibit β-catenin proteolysis remains largely elusive. This study reveals novel key molecular events in Wnt signaling: induction of Gsk3β ubiquitination and Gsk3β-β-TrCP binding. We found that Wnt stimulation induced prolonged monoubiquitination of Gsk3β and Gsk3β-β-TrCP interaction. Monoubiquitination did not cause Gsk3β degradation nor affects its enzymatic activity. Rather, increased monoubiquitination of Gsk3β/Gsk3β-β-TrCP association suppressed β-catenin recruitment of β-TrCP, leading to long-term inhibition of β-catenin ubiquitination and degradation.
Collapse
Affiliation(s)
- Chenxi Gao
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Guangming Chen
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Guillermo Romero
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Stergios Moschos
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; Division of Hematology/Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Xiang Xu
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Jing Hu
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213.
| |
Collapse
|
35
|
Colin-Cassin C, Yao X, Cerella C, Chbicheb S, Kuntz S, Mazerbourg S, Boisbrun M, Chapleur Y, Diederich M, Flament S, Grillier-Vuissoz I. PPARγ-inactive Δ2-troglitazone independently triggers ER stress and apoptosis in breast cancer cells. Mol Carcinog 2013; 54:393-404. [PMID: 24293218 DOI: 10.1002/mc.22109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 10/08/2013] [Accepted: 10/23/2013] [Indexed: 01/02/2023]
Abstract
Our aim was to better understand peroxisome proliferator-activated receptor gamma (PPARγ)-independent pathways involved in anti-cancer effects of thiazolidinediones (TZDs). We focused on Δ2-troglitazone (Δ2-TGZ), a PPARγ inactive TZD that affects breast cancer cell viability. Appearance of TUNEL positive cells, changes in mitochondrial membrane potential, cleavage of poly(ADP-ribose) polymerase (PARP)-1 and caspase-7 revealed that apoptosis occurred in both hormone-dependent MCF7 and hormone-independent MDA-MB-231 breast cancer cells after 24 and 48 h of treatment. A microarray study identified endoplasmic reticulum (ER) stress as an essential cellular function since many genes involved in ER stress were upregulated in MCF7 cells following Δ2-TGZ treatment. Δ2-TGZ-induced ER stress was further confirmed in MCF7 cells by phosphorylation of pancreatic endoplasmic reticulum kinase-like endoplasmic reticulum kinase (PERK) and its target eIF2α after 1.5 h, rapid increase in activating transcription factor (ATF) 3 mRNA levels, splicing of X-box binding protein 1 (XBP1) after 3 h, accumulation of binding immunogloblulin protein (BiP) and CCAAT-enhancer-binding protein homologous protein (CHOP) after 6 h. Immunofluorescence microscopy indicated that CHOP was relocalized to the nucleus of treated cells. Similarly, in MDA-MB-231 cells, overexpression of ATF3, splicing of XBP1, and accumulation of BiP and CHOP were observed following Δ2-TGZ treatment. In MCF7 cells, knock-down of CHOP or the inhibition of c-Jun N-terminal kinase (JNK) did not impair cleavage of PARP-1 and caspase-7. Altogether, our results show that ER stress is an early response of major types of breast cancer cells to Δ2-TGZ, prior to, but not causative of apoptosis.
Collapse
Affiliation(s)
- Christelle Colin-Cassin
- Université de Lorraine, CRAN, UMR 7039, Vandœuvre-lès-Nancy, France; CNRS, CRAN, UMR 7039, Vandœuvre-lès-Nancy, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Cho DH, Lee EJ, Kwon KJ, Shin CY, Song KH, Park JH, Jo I, Han SH. Troglitazone, a thiazolidinedione, decreases tau phosphorylation through the inhibition of cyclin-dependent kinase 5 activity in SH-SY5Y neuroblastoma cells and primary neurons. J Neurochem 2013; 126:685-95. [DOI: 10.1111/jnc.12264] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 03/11/2013] [Accepted: 04/10/2013] [Indexed: 01/21/2023]
Affiliation(s)
- Du-Hyong Cho
- Department of Neurology; Konkuk University Medical Center; Konkuk University; Seoul South Korea
- Department of Pharmacology; Center for Geriatric Neuroscience Research; SMART Institute of Advanced Biomedical Science School of Medicine; Konkuk University; Seoul South Korea
| | - Eun Joo Lee
- Department of Neurology; Konkuk University Medical Center; Konkuk University; Seoul South Korea
- Department of Pharmacology; Center for Geriatric Neuroscience Research; SMART Institute of Advanced Biomedical Science School of Medicine; Konkuk University; Seoul South Korea
| | - Kyoung Ja Kwon
- Department of Neurology; Konkuk University Medical Center; Konkuk University; Seoul South Korea
- Department of Pharmacology; Center for Geriatric Neuroscience Research; SMART Institute of Advanced Biomedical Science School of Medicine; Konkuk University; Seoul South Korea
| | - Chan Young Shin
- Department of Neurology; Konkuk University Medical Center; Konkuk University; Seoul South Korea
- Department of Pharmacology; Center for Geriatric Neuroscience Research; SMART Institute of Advanced Biomedical Science School of Medicine; Konkuk University; Seoul South Korea
| | - Kee-Ho Song
- Department of Internal Medicine; Konkuk University School of Medicine; Seoul South Korea
| | - Jung-Hyun Park
- Department of Molecular Medicine; Ewha Womans University Medical School; Seoul South Korea
| | - Inho Jo
- Department of Molecular Medicine; Ewha Womans University Medical School; Seoul South Korea
| | - Seol-Heui Han
- Department of Neurology; Konkuk University Medical Center; Konkuk University; Seoul South Korea
- Department of Pharmacology; Center for Geriatric Neuroscience Research; SMART Institute of Advanced Biomedical Science School of Medicine; Konkuk University; Seoul South Korea
| |
Collapse
|
37
|
Zhang X, Min KW, Wimalasena J, Baek SJ. Cyclin D1 degradation and p21 induction contribute to growth inhibition of colorectal cancer cells induced by epigallocatechin-3-gallate. J Cancer Res Clin Oncol 2012; 138:2051-60. [PMID: 22814742 PMCID: PMC3584327 DOI: 10.1007/s00432-012-1276-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 06/19/2012] [Indexed: 12/17/2022]
Abstract
PURPOSE The public has paid attention to green tea due to its health benefits. Epigallocatechin-3-gallate (EGCG), the major component of green tea, is well documented to induce apoptosis and cell cycle arrest in cancer cells by targeting multiple signal transduction pathways. However, the detailed mechanism(s) of action needs to be determined. METHODS Cell growth was evaluated by MTT assay, cell cycle analysis, and caspase 3/7 activity. Protein expression was analyzed through Western blotting. Reverse transcription polymerase chain reaction was used for examining mRNA expression of p21 and cyclin D1. The promoter activity of p21 was assessed by the luciferase reporter system. RESULTS We identified cyclin D1 and p21 as molecular targets of EGCG in human colorectal cancer cells. We observed that cyclin D1 was down-regulated, while p21 expression was up-regulated by EGCG in dose- and time-dependent manners. Furthermore, we found EGCG decreased cyclin D1 protein stability, therefore triggering ubiquitin-dependent proteasomal degradation. Meanwhile, EGCG increased p21 promoter activity, resulting in up-regulation of p21 mRNA and protein, which was likely dependent on extracellular-signal-regulated kinase (ERK), inhibitor of nuclear factor kappa-B kinase (IKK) and phosphoinositide 3-kinase (PI3 K). CONCLUSION The data presented here details a novel mechanism by which EGCG inhibits cell growth of colorectal cancer cells. Namely, EGCG-induced cyclin D1 degradation and p21 transcriptional activation partially contribute to growth suppression in these cells.
Collapse
Affiliation(s)
- Xiaobo Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, 2407 River Drive, Knoxville, TN 37996-4542, USA
| | - Kyung-Won Min
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, 2407 River Drive, Knoxville, TN 37996-4542, USA
| | - Jay Wimalasena
- Department of Obstetrics and Gynecology, Graduate School of Medicine, University of Tennessee, Knoxville, TN 37920, USA
| | - Seung Joon Baek
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, 2407 River Drive, Knoxville, TN 37996-4542, USA
| |
Collapse
|
38
|
Chu PC, Chuang HC, Kulp SK, Chen CS. The mRNA-stabilizing factor HuR protein is targeted by β-TrCP protein for degradation in response to glycolysis inhibition. J Biol Chem 2012; 287:43639-50. [PMID: 23115237 DOI: 10.1074/jbc.m112.393678] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The mRNA-stabilizing protein HuR acts a stress response protein whose function and/or protein stability are modulated by diverse stress stimuli through posttranslational modifications. Here, we report a novel mechanism by which metabolic stress facilitates proteasomal degradation of HuR in cancer cells. In response to the glucose transporter inhibitor CG-5, HuR translocates to the cytoplasm, where it is targeted by the ubiquitin E3 ligase β-TrCP1 for degradation. The cytoplasmic localization of HuR is facilitated by PKCα-mediated phosphorylation at Ser-318 as the Ser-318 → alanine substitution abolishes the ability of the resulting HuR to bind PKCα and to undergo nuclear export. The mechanistic link between β-TrCP1 and HuR degradation was supported by the ability of ectopically expressed β-TrCP1 to mimic CG-5 to promote HuR degradation and by the protective effect of dominant negative inhibition of β-TrCP1 on HuR ubiquitination and degradation. Substrate targeting of HuR by β-TrCP1 was further verified by coimmunoprecipitation and in vitro GST pull-down assays and by the identification of a β-TrCP1 recognition site. Although HuR does not contain a DSG destruction motif, we obtained evidence that β-TrCP1 recognizes an unconventional motif, (296)EEAMAIAS(304), in the RNA recognition motif 3. Furthermore, mutational analysis indicates that IKKα-dependent phosphorylation at Ser-304 is crucial to the binding of HuR to β-TrCP1. Mechanistically, this HuR degradation pathway differs from that reported for heat shock and hypoxia, which underlies the complexity in the regulation of HuR turnover under different stress stimuli. The ability of glycolysis inhibitors to target the expression of oncogenic proteins through HuR degradation might foster novel strategies for cancer therapy.
Collapse
Affiliation(s)
- Po-Chen Chu
- Division of Medicinal Chemistry, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43221, USA
| | | | | | | |
Collapse
|
39
|
Wei S, Chu PC, Chuang HC, Hung WC, Kulp SK, Chen CS. Targeting the oncogenic E3 ligase Skp2 in prostate and breast cancer cells with a novel energy restriction-mimetic agent. PLoS One 2012; 7:e47298. [PMID: 23071779 PMCID: PMC3470570 DOI: 10.1371/journal.pone.0047298] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/12/2012] [Indexed: 11/18/2022] Open
Abstract
Substantial evidence supports the oncogenic role of the E3 ubiquitin ligase S-phase kinase-associated protein 2 (Skp2) in many types of cancers through its ability to target a broad range of signaling effectors for ubiquitination. Thus, this oncogenic E3 ligase represents an important target for cancer drug discovery. In this study, we report a novel mechanism by which CG-12, a novel energy restriction-mimetic agent (ERMA), down-regulates the expression of Skp2 in prostate cancer cells. Pursuant to our previous finding that upregulation of β-transducin repeat-containing protein (β-TrCP) expression represents a cellular response in cancer cells to ERMAs, including CG-12 and 2-deoxyglucose, we demonstrated that this β-TrCP accumulation resulted from decreased Skp2 expression. Evidence indicates that Skp2 targets β-TrCP for degradation via the cyclin-dependent kinase 2-facilitated recognition of the proline-directed phosphorylation motif 412SP. This Skp2 downregulation was attributable to Sirt1-dependent suppression of COP9 signalosome (Csn)5 expression in response to CG-12, leading to increased cullin 1 neddylation in the Skp1-cullin1-F-box protein complex and consequent Skp2 destabilization. Moreover, we determined that Skp2 and β-TrCP are mutually regulated, providing a feedback mechanism that amplifies the suppressive effect of ERMAs on Skp2. Specifically, cellular accumulation of β-TrCP reduced the expression of Sp1, a β-TrCP substrate, which, in turn, reduced Skp2 gene expression. This Skp2-β-TrCP-Sp1 feedback loop represents a novel crosstalk mechanism between these two important F-box proteins in cancer cells with aberrant Skp2 expression under energy restriction, which provides a proof-of-concept that the oncogenic Csn5/Skp2 signaling axis represents a “druggable” target for this novel ERMA.
Collapse
Affiliation(s)
- Shuo Wei
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Po-Chen Chu
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Hsiao-Ching Chuang
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Wen-Chun Hung
- National Institute of Cancer Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan
| | - Samuel K. Kulp
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Ching-Shih Chen
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
- Institute of Basic Medical Sciences, National Cheng-Kung University, Tainan, Taiwan
- * E-mail:
| |
Collapse
|
40
|
Landry BD, Doyle JP, Toczyski DP, Benanti JA. F-box protein specificity for g1 cyclins is dictated by subcellular localization. PLoS Genet 2012; 8:e1002851. [PMID: 22844257 PMCID: PMC3405998 DOI: 10.1371/journal.pgen.1002851] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 06/06/2012] [Indexed: 01/16/2023] Open
Abstract
Levels of G1 cyclins fluctuate in response to environmental cues and couple mitotic signaling to cell cycle entry. The G1 cyclin Cln3 is a key regulator of cell size and cell cycle entry in budding yeast. Cln3 degradation is essential for proper cell cycle control; however, the mechanisms that control Cln3 degradation are largely unknown. Here we show that two SCF ubiquitin ligases, SCF(Cdc4) and SCF(Grr1), redundantly target Cln3 for degradation. While the F-box proteins (FBPs) Cdc4 and Grr1 were previously thought to target non-overlapping sets of substrates, we find that Cdc4 and Grr1 each bind to all 3 G1 cyclins in cell extracts, yet only Cln3 is redundantly targeted in vivo, due in part to its nuclear localization. The related cyclin Cln2 is cytoplasmic and exclusively targeted by Grr1. However, Cdc4 can interact with Cdk-phosphorylated Cln2 and target it for degradation when cytoplasmic Cdc4 localization is forced in vivo. These findings suggest that Cdc4 and Grr1 may share additional redundant targets and, consistent with this possibility, grr1Δ cdc4-1 cells demonstrate a CLN3-independent synergistic growth defect. Our findings demonstrate that structurally distinct FBPs are capable of interacting with some of the same substrates; however, in vivo specificity is achieved in part by subcellular localization. Additionally, the FBPs Cdc4 and Grr1 are partially redundant for proliferation and viability, likely sharing additional redundant substrates whose degradation is important for cell cycle progression.
Collapse
Affiliation(s)
- Benjamin D. Landry
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - John P. Doyle
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - David P. Toczyski
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Jennifer A. Benanti
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
41
|
Benanti JA. Coordination of cell growth and division by the ubiquitin-proteasome system. Semin Cell Dev Biol 2012; 23:492-8. [PMID: 22542766 DOI: 10.1016/j.semcdb.2012.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 04/13/2012] [Indexed: 01/25/2023]
Abstract
The coupling of cellular growth and division is crucial for a cell to make an accurate copy of itself. Regulated protein degradation by the ubiquitin-proteasome system (UPS) plays an important role in the coordination of these two processes. Many ubiquitin ligases, in particular the Skp1-Cullin-F-box (SCF) family and the Anaphase-Promoting Complex (APC), couple growth and division by targeting cell cycle and metabolic regulators for degradation. However, many regulatory proteins are targeted by multiple ubiquitin ligases. As a result, we are only just beginning to understand the complexities of the proteolytic regulatory network that connects cell growth and the cell cycle.
Collapse
Affiliation(s)
- Jennifer A Benanti
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| |
Collapse
|
42
|
Wang N, Pan W, Zhu M, Zhang M, Hao X, Liang G, Feng Y. Fangchinoline induces autophagic cell death via p53/sestrin2/AMPK signalling in human hepatocellular carcinoma cells. Br J Pharmacol 2012; 164:731-42. [PMID: 21418191 DOI: 10.1111/j.1476-5381.2011.01349.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Fangchinoline is a novel anti-tumour agent with little known of its cellular and molecular mechanisms of action. Here we have investigated the mode of cell death induced by fangchinoline and its underlying mechanism in two human hepatocellular carcinoma cell lines, HepG2 and PLC/PRF/5. EXPERIMENTAL APPROACH Apoptosis and autophagy were monitored in fangchinoline-treated HepG2 and PLC/PRF/5 cells by histological methods. The signal transduction pathways involved in activation of autophagy were examined, using immunoblotting, real-time PCR and siRNA techniques. KEY RESULTS Fangchinoline did not induce apoptosis in HepG2 and PLC/PRF/5 cells but triggered, dose-dependently, autophagy, an alternative mode of cell death which may contribute to fangchinoline's anti-tumour action. Nuclear translocation of p53 was involved in induction of autophagy by fangchinoline, followed by selective transactivation of the autophagy-related gene sestrin2 and initiation of the autophagic process. Signalling by the AMP-activated protein kinase was also involved as a downstream target of sestrin2 and induced mTOR-independent autophagic cell death in both cell lines. siRNA for Atg 5 or pharmacological block of p53 abolished fangchinoline-induced autophagy and inhibition of autophagy switched cell death to apoptosis in these cells, suggesting that cell death is irreversible once autophagy is induced by fangchinoline. CONCLUSIONS AND IMPLICATIONS Fangchinoline is a highly specific agent inducing autophagic cell death in hepatocellular carcinoma cells with a novel mechanism, which elucidates the potential of fangchinoline to potentiate programmed cell death in cancer cells.
Collapse
Affiliation(s)
- Ning Wang
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | | | | | | | | | | | | |
Collapse
|
43
|
Salamone S, Colin C, Grillier-Vuissoz I, Kuntz S, Mazerbourg S, Flament S, Martin H, Richert L, Chapleur Y, Boisbrun M. Synthesis of new troglitazone derivatives: anti-proliferative activity in breast cancer cell lines and preliminary toxicological study. Eur J Med Chem 2012; 51:206-15. [PMID: 22409968 DOI: 10.1016/j.ejmech.2012.02.044] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 02/20/2012] [Accepted: 02/21/2012] [Indexed: 02/08/2023]
Abstract
Breast cancer is the most prevalent cancer in women. The development of resistances to therapeutic agents and the absence of targeted therapy for triple negative breast cancer motivate the search for alternative treatments. With this aim in mind, we synthesised new derivatives of troglitazone, a compound which was formerly used as an anti-diabetic agent and which exhibits anti-proliferative activity on various cancer cell lines. Among the compounds prepared, some displayed micromolar activity against hormone-dependent and hormone-independent breast cancer cells. Furthermore, the influence of the compounds on the viability of primary cultures of human hepatocytes was evaluated. This enabled us to obtain for the first time interesting structure-toxicity relationships in this family of compounds, resulting in 6b and 8b, which show good anti-proliferative activities and poor toxicity towards hepatocytes, compared to troglitazone.
Collapse
Affiliation(s)
- Stéphane Salamone
- Groupe SUCRES, UMR 7565, Nancy-Université-CNRS, BP 70239, F-54506 Vandoeuvre-lès-Nancy, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
The PPAR Gamma Agonist Troglitazone Regulates Erk 1/2 Phosphorylation via a PPARγ-Independent, MEK-Dependent Pathway in Human Prostate Cancer Cells. PPAR Res 2012; 2012:929052. [PMID: 22448169 PMCID: PMC3289875 DOI: 10.1155/2012/929052] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/22/2011] [Accepted: 11/23/2011] [Indexed: 12/20/2022] Open
Abstract
Thiazolidinediones (TZDs) dramatically reduce the growth of human prostate cancer cells in vitro and in vivo. To determine whether the antitumor effects of TZDs were due in part to changes in the MEK/Erk signaling pathway, we examined the regulation of Erk phosphorylation by the TZD troglitazone within the PC-3 and C4-2 human prostate cancer cell lines. Western blot analysis revealed troglitazone-induced phosphorylation of Erk in both PC-3 and C4-2 cells. Troglitazone-induced increases in Erk phosphorylation were suppressed by the MEK inhibitor U0126 but not by the PPARγ antagonist GW9662. Pretreatment with U0126 did not alter the ability of troglitazone to regulate expression of two proteins that control cell cycle, p21, and c-Myc. Troglitazone was also still effective at reducing PC-3 proliferation in the presence of U0126. Therefore, our data suggest that troglitazone-induced Erk phosphorylation does not significantly contribute to the antiproliferative effect of troglitazone.
Collapse
|
45
|
Ponyeam W, Hagen T. Characterization of the Cullin7 E3 ubiquitin ligase — Heterodimerization of cullin substrate receptors as a novel mechanism to regulate cullin E3 ligase activity. Cell Signal 2012; 24:290-5. [DOI: 10.1016/j.cellsig.2011.08.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 08/28/2011] [Indexed: 10/17/2022]
|
46
|
Genetic reevaluation of the role of F-box proteins in cyclin D1 degradation. Mol Cell Biol 2011; 32:590-605. [PMID: 22124152 DOI: 10.1128/mcb.06570-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
D-type cyclins play a pivotal role in G(1)-S progression of the cell cycle, and their expression is frequently deregulated in cancer. Cyclin D1 has a half-life of only ~30 min as a result of its ubiquitylation and proteasomal degradation, with various F-box proteins, including Fbxo4, Fbxw8, Skp2, and Fbxo31, having been found to contribute to its ubiquitylation. We have now generated Fbxo4-deficient mice and found no abnormalities in these animals. Cyclin D1 accumulation was thus not observed in Fbxo4(-/-) mouse tissues. The half-life of cyclin D1 in mouse embryonic fibroblasts (MEFs) prepared from Fbxo4(-/-), Fbxw8(-/-), and Fbxo4(-/-); Fbxw8(-/-) mice also did not differ from that in wild-type MEFs. Additional depletion of Skp2 and Fbxo31 in Fbxo4(-/-); Fbxw8(-/-) MEFs by RNA interference did not affect cyclin D1 stability. Although Fbxo31 depletion in MEFs increased cyclin D1 abundance, this effect appeared attributable to upregulation of cyclin D1 mRNA. Furthermore, abrogation of the function of the Skp1-Cul1-F-box protein (SCF) complex or the anaphase-promoting complex/cyclosome (APC/C) complexes did not alter the half-life of cyclin D1, whereas cyclin D1 degradation was dependent largely on proteasome activity. Our genetic analyses thus do not support a role for any of the four F-box proteins examined in cyclin D1 degradation during normal cell cycle progression. They suggest the existence of other ubiquitin ligases that target cyclin D1 for proteolysis.
Collapse
|
47
|
The Ras inhibitors caveolin-1 and docking protein 1 activate peroxisome proliferator-activated receptor γ through spatial relocalization at helix 7 of its ligand-binding domain. Mol Cell Biol 2011; 31:3497-510. [PMID: 21690289 DOI: 10.1128/mcb.01421-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a transcription factor that promotes differentiation and cell survival in the stomach. PPARγ upregulates and interacts with caveolin-1 (Cav1), a scaffold protein of Ras/mitogen-activated protein kinases (MAPKs). The cytoplasmic-to-nuclear localization of PPARγ is altered in gastric cancer (GC) patients, suggesting a so-far-unknown role for Cav1 in spatial regulation of PPARγ signaling. We show here that loss of Cav1 accelerated proliferation of normal stomach and GC cells in vitro and in vivo. Downregulation of Cav1 increased Ras/MAPK-dependent phosphorylation of serine 84 in PPARγ and enhanced nuclear translocation and ligand-independent transcription of PPARγ target genes. In contrast, Cav1 overexpression sequestered PPARγ in the cytosol through interaction of the Cav1 scaffolding domain (CSD) with a conserved hydrophobic motif in helix 7 of PPARγ's ligand-binding domain. Cav1 cooperated with the endogenous Ras/MAPK inhibitor docking protein 1 (Dok1) to promote the ligand-dependent transcriptional activity of PPARγ and to inhibit cell proliferation. Ligand-activated PPARγ also reduced tumor growth and upregulated the Ras/MAPK inhibitors Cav1 and Dok1 in a murine model of GC. These results suggest a novel mechanism of PPARγ regulation by which Ras/MAPK inhibitors act as scaffold proteins that sequester and sensitize PPARγ to ligands, limiting proliferation of gastric epithelial cells.
Collapse
|
48
|
Akinyeke TO, Stewart LV. Troglitazone suppresses c-Myc levels in human prostate cancer cells via a PPARγ-independent mechanism. Cancer Biol Ther 2011; 11:1046-58. [PMID: 21525782 DOI: 10.4161/cbt.11.12.15709] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Troglitazone is a ligand for the peroxisome proliferator activated receptor gamma (PPARγ) that decreases growth of human prostate cancer cells in vitro and in vivo. However, the mechanism by which troglitazone reduces prostate cancer cell growth is not fully understood. To understand the signaling pathways involved in troglitazone-induced decreases in prostate cancer growth, we examined the effect of troglitazone on androgen-independent C4-2 human prostate cancer cells. Initial experiments revealed troglitazone inhibited C4-2 cell proliferation by arresting cells in the G(0)/G(1) phase of the cell cycle and inducing apoptosis. Since the proto-oncogene product c-Myc regulates both apoptosis and cell cycle progression, we next examined whether troglitazone altered expression of c-Myc. Troglitazone decreased c-Myc protein levels as well as expression of downstream targets of c-Myc in a dose-dependent manner. In C4-2 cells, troglitazone-induced decreases in c-Myc protein involve proteasome-mediated degradation of c-Myc protein as well as reductions in c-Myc mRNA levels. It appears that troglitazone stimulates degradation of c-Myc by increasing c-Myc phosphorylation, for the level of phosphorylated c-Myc was elevated in prostate cancer cells exposed to troglitazone. While troglitazone dramatically decreased the amount of c-Myc within C4-2 cells, the PPARγ ligands ciglitazone, rosiglitazone and pioglitazone did not reduce c-Myc protein levels. Furthermore the down-regulation of c-Myc by troglitazone was not blocked by the PPARγ antagonist GW9662 and siRNA-mediated decreases in PPARγ protein. Thus, our data suggest that troglitazone reduces c-Myc protein independently of PPARγ.
Collapse
Affiliation(s)
- Tunde O Akinyeke
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN, USA
| | | |
Collapse
|
49
|
Kim AJ, Kim HJ, Jee HJ, Song N, Kim M, Bae YS, Chung JH, Yun J. Glucose deprivation is associated with Chk1 degradation through the ubiquitin-proteasome pathway and effective checkpoint response to replication blocks. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1230-8. [PMID: 21440578 DOI: 10.1016/j.bbamcr.2011.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 11/19/2022]
Abstract
Chk1 plays a key role in the DNA replication checkpoint and in preserving genomic integrity. Previous studies have shown that reduced Chk1 function leads to defects in the checkpoint response and is closely associated with tumorigenesis. Here, we report that glucose deprivation caused the degradation of Chk1 protein without perturbing cell cycle progression. The induction of Chk1 degradation in response to glucose deprivation was observed in various cancer cell lines and in normal human fibroblasts. Therefore, it appears to be a universal phenomenon in mammalian cells. A specific proteasome inhibitor blocked glucose deprivation-induced Chk1 degradation. Ubiquitination of Chk1 was detected, indicating that the proteasome-ubiquitin pathway mediates Chk1 degradation upon glucose deprivation. Mechanistic studies have demonstrated that ATR-dependent phosphorylation of Chk1 at the Ser317 and Ser345 sites is not required, suggesting that the molecular mechanism for Chk1 degradation upon glucose deprivation is distinct from genotoxic stress-induced degradation. Under conditions of glucose deprivation, the cells manifested a defective checkpoint response to replication stress, camptothecin or hydroxyurea. The forced expression of Myc-Chk1 partially rescued the defective response to the replication block upon glucose deprivation. Taken together, our results indicate that glucose deprivation induces ubiquitin-mediated Chk1 degradation and defective checkpoint responses, implying its potential role in genomic instability and tumor development.
Collapse
Affiliation(s)
- Ae Jeong Kim
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Specific thiazolidinediones inhibit ovarian cancer cell line proliferation and cause cell cycle arrest in a PPARγ independent manner. PLoS One 2011; 6:e16179. [PMID: 21283708 PMCID: PMC3025024 DOI: 10.1371/journal.pone.0016179] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 12/14/2010] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Peroxisome Proliferator Activated Receptor gamma (PPARγ) agonists, such as the thiazolinediones (TZDs), have been studied for their potential use as cancer therapeutic agents. We investigated the effect of four TZDs--Rosiglitazone (Rosi), Ciglitazone (CGZ), Troglitazone (TGZ), and Pioglitazone (Pio)--on ovarian cancer cell proliferation, PPARγ expression and PPAR luciferase reporter activity. We explored whether TZDs act in a PPARγ dependent or independent manner by utilizing molecular approaches to inhibit or overexpress PPARγ activity. PRINCIPAL FINDINGS Treatment with CGZ or TGZ for 24 hours decreased proliferation in three ovarian cancer cell lines, Ovcar3, CaOv3, and Skov3, whereas Rosi and Pio had no effect. This decrease in Ovcar3 cell proliferation was due to a higher fraction of cells in the G(0)/G(1) stage of the cell cycle. CGZ and TGZ treatment increased apoptosis after 4 hours of treatment but not after 8 or 12 hours. Treatment with TGZ or CGZ increased PPARγ mRNA expression in Ovcar3 cells; however, protein levels were unchanged. Surprisingly, luciferase promoter assays revealed that none of the TZDs increased PPARγ activity. Overexpression of wild type PPARγ increased reporter activity. This was further augmented by TGZ, Rosi, and Pio indicating that these cells have the endogenous capacity to mediate PPARγ transactivation. To determine whether PPARγ mediates the TZD-induced decrease in proliferation, cells were treated with CGZ or TGZ in the absence or presence of a dominant negative (DN) or wild type overexpression PPARγ construct. Neither vector changed the TZD-mediated cell proliferation suggesting this effect of TZDs on ovarian cancer cells may be PPARγ independent. CONCLUSIONS CGZ and TGZ cause a decrease in ovarian cancer cell proliferation that is PPARγ independent. This concept is supported by the finding that a DN or overexpression of the wild type PPARγ did not affect the changes in cell proliferation and cell cycle.
Collapse
|