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Hu J, Xu H, Ma X, Bai M, Zhou Y, Miao R, Wang F, Li X, Cheng B. Modulating PCGF4/BMI1 Stability Is an Efficient Metastasis-Regulatory Strategy Used by Distinct Subtypes of Cancer-Associated Fibroblasts in Intrahepatic Cholangiocarcinoma. THE AMERICAN JOURNAL OF PATHOLOGY 2024; 194:1388-1404. [PMID: 38670529 DOI: 10.1016/j.ajpath.2024.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/17/2024] [Accepted: 03/21/2024] [Indexed: 04/28/2024]
Abstract
Intrahepatic cholangiocarcinoma (ICC) is a highly malignant neoplasm prone to metastasis. Whether cancer-associated fibroblasts (CAFs) affect the metastasis of ICC is unclear. Herein, ICC patient-derived CAF lines and related cancerous cell lines were established and the effects of CAFs on the tumor progressive properties of the ICC cancerous cells were analyzed. CAFs could be classified into cancer-restraining or cancer-promoting categories based on distinct tumorigenic effects. The RNA-sequencing analyses of ICC cancerous cell lines identified polycomb group ring finger 4 (PCGF4; alias BMI1) as a potential metastasis regulator. The changes of PCGF4 levels in ICC cells mirrored the restraining or promoting effects of CAFs on ICC migration. Immunohistochemical analyses on the ICC tissue microarrays indicated that PCGF4 was negatively correlated with overall survival of ICC. The promoting effects of PCGF4 on cell migration, drug resistance activity, and stemness properties were confirmed. Mechanistically, cancer-restraining CAFs triggered the proteasome-dependent degradation of PCGF4, whereas cancer-promoting CAFs enhanced the stability of PCGF4 via activating the IL-6/phosphorylated STAT3 pathway. In summary, the current data identified the role of CAFs in ICC metastasis and revealed a new mechanism of the CAFs on ICC progression in which PCGF4 acted as the key effector by both categories of CAFs. These findings shed light on developing comprehensive therapeutic strategies for ICC.
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Affiliation(s)
- Jinjing Hu
- School of Life Sciences, Lanzhou University, Lanzhou, China; Key Laboratory Biotherapy and Regenerative Medicine of Gansu Province, Lanzhou, China
| | - Hao Xu
- The Fourth Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou, China; The First School of Clinical Medicine, Lanzhou University, Lanzhou, China
| | - Xiaojun Ma
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Mingzhen Bai
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, China
| | - Yongqiang Zhou
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, China
| | - Ruidong Miao
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Fanghong Wang
- The Fourth Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou, China; The First School of Clinical Medicine, Lanzhou University, Lanzhou, China
| | - Xun Li
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, China; Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou, China.
| | - Bo Cheng
- School of Life Sciences, Lanzhou University, Lanzhou, China; Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou, China.
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2
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Herzog AE, Somayaji R, Nör JE. Bmi-1: A master regulator of head and neck cancer stemness. FRONTIERS IN ORAL HEALTH 2023; 4:1080255. [PMID: 36726797 PMCID: PMC9884974 DOI: 10.3389/froh.2023.1080255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/02/2023] [Indexed: 01/18/2023] Open
Abstract
Head and neck cancers are composed of a diverse group of malignancies, many of which exhibit an unacceptably low patient survival, high morbidity and poor treatment outcomes. The cancer stem cell (CSC) hypothesis provides an explanation for the substantial patient morbidity associated with treatment resistance and the high frequency of tumor recurrence/metastasis. Stem cells are a unique population of cells capable of recapitulating a heterogenous organ from a single cell, due to their capacity to self-renew and differentiate into progenitor cells. CSCs share these attributes, in addition to playing a pivotal role in cancer initiation and progression by means of their high tumorigenic potential. CSCs constitute only a small fraction of tumor cells but play a major role in tumor initiation and therapeutic evasion. The shift towards stem-like phenotype fuels many malignant features of a cancer cell and mediates resistance to conventional chemotherapy. Bmi-1 is a master regulator of stem cell self-renewal as part of the polycomb repressive complex 1 (PRC1) and has emerged as a prominent player in cancer stem cell biology. Bmi-1 expression is upregulated in CSCs, which is augmented by tumor-promoting factors and various conventional chemotherapies. Bmi-1+ CSCs mediate chemoresistance and metastasis. On the other hand, inhibiting Bmi-1 rescinds CSC function and re-sensitizes cancer cells to chemotherapy. Therefore, elucidating the functional role of Bmi-1 in CSC-mediated cancer progression may unveil an attractive target for mechanism-based, developmental therapeutics. In this review, we discuss the parallels in the role of Bmi-1 in stem cell biology of health and disease and explore how this can be leveraged to advance clinical treatment strategies for head and neck cancer.
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Affiliation(s)
- Alexandra E. Herzog
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, United States
| | - Ritu Somayaji
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, United States
| | - Jacques E. Nör
- Department of Cariology, Restorative Sciences, Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, United States,Department of Otolaryngology – Head and Neck Surgery, University of Michigan Medical School; Ann Arbor, MI, United States,Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, United States,Universityof Michigan Rogel Cancer Center, Ann Arbor, MI, United States
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3
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Rodriguez-Ramirez C, Zhang Z, Warner KA, Herzog AE, Mantesso A, Zhang Z, Yoon E, Wang S, Wicha MS, Nör JE. p53 Inhibits Bmi-1-driven Self-Renewal and Defines Salivary Gland Cancer Stemness. Clin Cancer Res 2022; 28:4757-4770. [PMID: 36048559 PMCID: PMC9633396 DOI: 10.1158/1078-0432.ccr-22-1357] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/01/2022] [Accepted: 08/30/2022] [Indexed: 01/24/2023]
Abstract
PURPOSE Mucoepidermoid carcinoma (MEC) is a poorly understood salivary gland malignancy with limited therapeutic options. Cancer stem cells (CSC) are considered drivers of cancer progression by mediating tumor recurrence and metastasis. We have shown that clinically relevant small molecule inhibitors of MDM2-p53 interaction activate p53 signaling and reduce the fraction of CSC in MEC. Here we examined the functional role of p53 in the plasticity and self-renewal of MEC CSC. EXPERIMENTAL DESIGN Using gene silencing and therapeutic activation of p53, we analyzed the cell-cycle profiles and apoptosis levels of CSCs in MEC cell lines (UM-HMC-1, -3A, -3B) via flow cytometry and looked at the effects on survival/self-renewal of the CSCs through sphere assays. We evaluated the effect of p53 on tumor development (N = 51) and disease recurrence (N = 17) using in vivo subcutaneous and orthotopic murine models of MEC. Recurrence was followed for 250 days after tumor resection. RESULTS Although p53 activation does not induce MEC CSC apoptosis, it reduces stemness properties such as self-renewal by regulating Bmi-1 expression and driving CSC towards differentiation. In contrast, downregulation of p53 causes expansion of the CSC population while promoting tumor growth. Remarkably, therapeutic activation of p53 prevented CSC-mediated tumor recurrence in preclinical trials. CONCLUSIONS Collectively, these results demonstrate that p53 defines the stemness of MEC and suggest that therapeutic activation of p53 might have clinical utility in patients with salivary gland MEC.
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Affiliation(s)
| | - Zhaocheng Zhang
- Department of Restorative Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Kristy A. Warner
- Department of Restorative Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Alexandra E. Herzog
- Department of Restorative Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Andrea Mantesso
- Department of Restorative Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Zhixiong Zhang
- Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, USA
| | - Eusik Yoon
- Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, USA
| | - Shaomeng Wang
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI, USA,Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI, USA,Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Max S. Wicha
- Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI, USA,Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Jacques E. Nör
- Department of Restorative Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA,Department of Biomedical Engineering, University of Michigan College of Engineering, Ann Arbor, MI, USA,Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA,Department of Otolaryngology, University of Michigan School of Medicine, Ann Arbor, Michigan, 48109, USA
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4
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Yang D, Liu HQ, Yang Z, Fan D, Tang QZ. BMI1 in the heart: Novel functions beyond tumorigenesis. EBioMedicine 2021; 63:103193. [PMID: 33421944 PMCID: PMC7804972 DOI: 10.1016/j.ebiom.2020.103193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 12/16/2022] Open
Abstract
The BMI1 protein, a member of the PRC1 family, is a well recognised transcriptional suppressor and has the capability of maintaining the self-renewal and proliferation of tissue-specific stem cells. Numerous studies have established that BMI1 is highly expressed in a variety of malignant cancers and serves as a key regulator in the tumorigenesis process. However, our understanding of BMI1 in terminally differentiated organs, such as the heart, is relatively nascent. Importantly, emerging data support that, beyond the tumor, BMI1 is also expressed in the heart tissue and indeed exerts profound effects in various cardiac pathological conditions. This review gives a summary of the novel functions of BMI1 in the heart, including BMI1-positive cardiac stem cells and BMI1-mediated signaling pathways, which are involved in the response to various cardiac pathological stimuli. Besides, we summarize the recent progress of BMI1 in some novel and rapidly developing cardiovascular therapies. Furtherly, we highlight the properties of BMI1, a therapeutic target proved effective in cancer treatment, as a promising target to alleviate cardiovascular diseases.
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Affiliation(s)
- Dan Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China
| | - Han-Qing Liu
- Department of Thyroid and Breast, Renmin Hospital of Wuhan University, Wuhan 430060, PR China
| | - Zheng Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China
| | - Di Fan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China.
| | - Qi-Zhu Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, PR China.
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5
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Geng Z, Gao Z. Mammalian PRC1 Complexes: Compositional Complexity and Diverse Molecular Mechanisms. Int J Mol Sci 2020; 21:E8594. [PMID: 33202645 PMCID: PMC7697839 DOI: 10.3390/ijms21228594] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
Polycomb group (PcG) proteins function as vital epigenetic regulators in various biological processes, including pluripotency, development, and carcinogenesis. PcG proteins form multicomponent complexes, and two major types of protein complexes have been identified in mammals to date, Polycomb Repressive Complexes 1 and 2 (PRC1 and PRC2). The PRC1 complexes are composed in a hierarchical manner in which the catalytic core, RING1A/B, exclusively interacts with one of six Polycomb group RING finger (PCGF) proteins. This association with specific PCGF proteins allows for PRC1 to be subdivided into six distinct groups, each with their own unique modes of action arising from the distinct set of associated proteins. Historically, PRC1 was considered to be a transcription repressor that deposited monoubiquitylation of histone H2A at lysine 119 (H2AK119ub1) and compacted local chromatin. More recently, there is increasing evidence that demonstrates the transcription activation role of PRC1. Moreover, studies on the higher-order chromatin structure have revealed a new function for PRC1 in mediating long-range interactions. This provides a different perspective regarding both the transcription activation and repression characteristics of PRC1. This review summarizes new advancements regarding the composition of mammalian PRC1 and accompanying explanations of how diverse PRC1-associated proteins participate in distinct transcription regulation mechanisms.
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Affiliation(s)
- Zhuangzhuang Geng
- Departments of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA 17033, USA;
| | - Zhonghua Gao
- Departments of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA 17033, USA;
- Penn State Hershey Cancer Institute, Hershey, PA 17033, USA
- The Stem Cell and Regenerative Biology Program, Penn State College of Medicine, Hershey, PA 17033, USA
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6
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Wang H, Zhu Y, Hu L, Li Y, Liu G, Xia T, Xiong D, Luo Y, Liu B, An Y, Li M, Huang Y, Zhong Q, Zeng M. Internal Ribosome Entry Sites Mediate Cap-Independent Translation of Bmi1 in Nasopharyngeal Carcinoma. Front Oncol 2020; 10:1678. [PMID: 33014838 PMCID: PMC7506037 DOI: 10.3389/fonc.2020.01678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 07/29/2020] [Indexed: 01/03/2023] Open
Abstract
Bmi1 is overexpressed in multiple human cancers. We previously reported the oncogenic function and the transcription regulation mechanisms of Bmi1 in nasopharyngeal carcinoma (NPC). In this study, we observed that the mRNA and the protein levels of Bmi1 were strictly inconsistent in NPC cell lines and cancer tissues. The inhibitors of proteasome and lysosome could not enhance the protein level of Bmi1, indicating that Bmi1 may be post-transcriptionally regulated. The IRESite analysis showed that there were two potential internal ribosome entry sites (IRESs) in the 5'-untranslated region (5'-UTR) of Bmi1. The luciferase assay demonstrated that the 5'-UTR of Bmi1 has IRES activity, which may mediate cap-independent translation. The IRES activity of the Bmi1 5'-UTR was significantly reduced after the mutation of the two IRES elements. Taken together, these results suggested that the IRES elements mediating translation is a novel post-transcriptional regulation mechanism of Bmi1.
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Affiliation(s)
- Hongbo Wang
- Guangdong Provincial Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.,State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yunjia Zhu
- Guangdong Provincial Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Lijuan Hu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China.,Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Peking University People's Hospital, Peking University Institute of Hematology, Beijing, China
| | - Yangyang Li
- Department of Pathology, Sun Yat-sen Memorial Hospital, Guangzhou, China
| | - Guihong Liu
- Tungwah Hospital of Sun Yat-sen University, Dongguan, China
| | - Tianliang Xia
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Dan Xiong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China.,Department of Laboratory Medicine, Luohu District People's Hospital, Shenzhen, China
| | - Yiling Luo
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Binliu Liu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yu An
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Manzhi Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yuehua Huang
- Guangdong Provincial Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Qian Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Musheng Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
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7
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Sarfraz M, Afzal A, Khattak S, Saddozai UAK, Li HM, Zhang QQ, Madni A, Haleem KS, Duan SF, Wu DD, Ji SP, Ji XY. Multifaceted behavior of PEST sequence enriched nuclear proteins in cancer biology and role in gene therapy. J Cell Physiol 2020; 236:1658-1676. [PMID: 32841373 DOI: 10.1002/jcp.30011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/18/2020] [Accepted: 08/04/2020] [Indexed: 01/12/2023]
Abstract
The amino acid sequence enriched with proline (P), glutamic acid (E), serine (S), and threonine (T) (PEST) is a signal-transducing agent providing unique features to its substrate nuclear proteins (PEST-NPs). The PEST motif is responsible for particular posttranslational modifications (PTMs). These PTMs impart distinct properties to PEST-NPs that are responsible for their activation/inhibition, intracellular localization, and stability/degradation. PEST-NPs participate in cancer metabolism, immunity, and protein transcription as oncogenes or as tumor suppressors. Gene-based therapeutics are getting the attention of researchers because of their cell specificity. PEST-NPs are good targets to explore as cancer therapeutics. Insights into PTMs of PEST-NPs demonstrate that these proteins not only interact with each other but also recruit other proteins to/from their active site to promote/inhibit tumors. Thus, the role of PEST-NPs in cancer biology is multivariate. It is hard to obtain therapeutic objectives with single gene therapy. An especially designed combination gene therapy might be a promising strategy in cancer treatment. This review highlights the multifaceted behavior of PEST-NPs in cancer biology. We have summarized a number of studies to address the influence of structure and PEST-mediated PTMs on activation, localization, stability, and protein-protein interactions of PEST-NPs. We also recommend researchers to adopt a pragmatic approach in gene-based cancer therapy.
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Affiliation(s)
- Muhammad Sarfraz
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China.,Faculty of Pharmacy, The University of Lahore, Lahore, Punjab, Pakistan.,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular Medicine, Henan University, Kaifeng, Henan, China
| | - Attia Afzal
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China.,Faculty of Pharmacy, The University of Lahore, Lahore, Punjab, Pakistan
| | - Saadullah Khattak
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China
| | - Umair A K Saddozai
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China
| | - Hui-Min Li
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China.,Department of Histology and Embryology, Cell Signal Transduction Laboratory, School of Basic Medical Sciences, Bioinformatics Centre, Institute of Biomedical Informatics, Henan University, Kaifeng, Henan, China
| | - Qian-Qian Zhang
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China
| | - Asadullah Madni
- Faculty of Pharmacy and Alternative Medicine, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
| | - Kashif S Haleem
- Department of Microbiology, Hazara University, Mansehra, Pakistan
| | - Shao-Feng Duan
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China.,School of Pharmacy, Institute for Innovative Drug Design and Evaluation, Henan University, Kaifeng, Henan, China
| | - Dong-Dong Wu
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China.,School of Stomatology, Henan University, Kaifeng, Henan, China
| | - Shao-Ping Ji
- Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular Medicine, Henan University, Kaifeng, Henan, China
| | - Xin-Ying Ji
- Henan International Joint Laboratory for Nuclear Protein Regulation & Kaifeng Key Laboratory of Infectious Diseases and Bio-safety, School of Basic Medical Sciences, Henan University College of Medicine, Kaifeng, Henan, China
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8
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Liu Q, Li Q, Zhu S, Yi Y, Cao Q. B lymphoma Moloney murine leukemia virus insertion region 1: An oncogenic mediator in prostate cancer. Asian J Androl 2020; 21:224-232. [PMID: 29862993 PMCID: PMC6498728 DOI: 10.4103/aja.aja_38_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1), a core member of polycomb repressive complex 1 (PRC1), has been intensely investigated in the field of cancer epigenetics for decades. Widely known as a critical regulator in cellular physiology, BMI1 is essential in self-renewal and differentiation in different lineages of stem cells. BMI1 also plays a significant role in cancer etiology for its involvement in pathological progress such as epithelial–mesenchymal transition (EMT) and cancer stem cell maintenance, propagation, and differentiation. Importantly, overexpression of BMI1 is predictive for drug resistance, tumor recurrence, and eventual therapy failure of various cancer subtypes, which renders the pharmacological targeting at BMI1 as a novel and promising therapeutic approach. The study on prostate cancer, a prevalent hormone-related cancer among men, has promoted enormous research advancements in cancer genetics and epigenetics. This review summarizes the role of BMI1 as an oncogenic and epigenetic regulator in tumor initiation, progression, and relapse of prostate cancer.
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Affiliation(s)
- Qipeng Liu
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA.,Xiangya School of Medicine, Central South University, Changsha 410008, China
| | - Qiaqia Li
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA.,Xiangya School of Medicine, Central South University, Changsha 410008, China
| | - Sen Zhu
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Yang Yi
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA.,Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China.,Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
| | - Qi Cao
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA.,Houston Methodist Cancer Center, Houston Methodist Research Institute, Houston, TX 77030, USA.,Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA
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9
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Qiu GZ, Liu Q, Wang XG, Xu GZ, Zhao T, Lou MQ. Hypoxia-induced USP22-BMI1 axis promotes the stemness and malignancy of glioma stem cells via regulation of HIF-1α. Life Sci 2020; 247:117438. [PMID: 32070708 DOI: 10.1016/j.lfs.2020.117438] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 11/19/2022]
Abstract
AIMS This study intends to investigate the mechanisms of ubiqutin-specific protease 22 (USP22)/B cell-specific Moloney murine leukemia virus integration site 1 (BMI1) on the biological phenotypes of glioma stem cells (GSCs) under hypoxia. MAIN METHODS Western blot, Cell Counting Kit-8, colony formation and flow cytometry assays were preformed to evaluate cells biological behaviors. Luciferase assay was utilized to identify the associations among USP22, HIF-1α and BMI1. KEY FINDINGS Silencing USP22 reduced the stemness and proliferation of GSCs, and increased its apoptosis in response to hypoxia. Whilst, overexpression of BMI1 reversed these phenomena. Whilst, a significant decrease in proliferation and stemness of GSCs caused by HIF-1α exhaustion were inversed by overexpression of USP22 or BMI1. SIGNIFICANCE Function of USP22-BMI1 on biological behaviors of GSCs was regulated by HIF-1α in response to hypoxia.
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Affiliation(s)
- Guan-Zhong Qiu
- The Neurosurgery Department of the Shanghai General Hospital, Shanghai Jiaotong University, No. 85 Wujin Road, Hongkou District, Shanghai, PR China; The Neurosurgery Department of the 960th Hospital of Joint Logistics Support Force, The Chinese People's Liberation Army, No. 25 Shifan Road, Beicun Street, Worker's New Village, Tianqiao District, Jinan, Shandong Province, PR China.
| | - Qiang Liu
- The Neurosurgery Department of the 960th Hospital of Joint Logistics Support Force, The Chinese People's Liberation Army, No. 25 Shifan Road, Beicun Street, Worker's New Village, Tianqiao District, Jinan, Shandong Province, PR China
| | - Xiao-Gang Wang
- The Neurosurgery Department of the 960th Hospital of Joint Logistics Support Force, The Chinese People's Liberation Army, No. 25 Shifan Road, Beicun Street, Worker's New Village, Tianqiao District, Jinan, Shandong Province, PR China
| | - Guang-Zhen Xu
- The Neurosurgery Department of the 960th Hospital of Joint Logistics Support Force, The Chinese People's Liberation Army, No. 25 Shifan Road, Beicun Street, Worker's New Village, Tianqiao District, Jinan, Shandong Province, PR China
| | - Tong Zhao
- Department of Neurosurgery, Huashan Hospital, Fudan University, No. 12 Urumqi Middle Road, Jing'an District, Shanghai, PR China
| | - Mei-Qing Lou
- The Neurosurgery Department of the Shanghai General Hospital, Shanghai Jiaotong University, No. 85 Wujin Road, Hongkou District, Shanghai, PR China.
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10
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Wang X, Wu K, Xiao LK, Wu XY. ShRNA-mediated BMI-1 gene silencing inhibits gastrointestinal stromal tumor cell telomerase activity and enhances apoptosis. Kaohsiung J Med Sci 2018; 34:606-615. [PMID: 30392567 DOI: 10.1016/j.kjms.2018.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 11/15/2022] Open
Abstract
Gastrointestinal stromal tumors (GISTs) are the most frequently occurring mesenchymal tumors of the gastrointestinal tract. Telomerase activity is well acknowledged as a critical factor in oncogenesis. The objective of the present study is to evaluate the effect of BMI gene silencing on proliferation, apoptosis and telomerase activity in human GIST882 cells. GIST882 cells were transfected with a eukaryotic expression vector of an shRNA fragment. The silencing efficiency in the GIST882 cells was determined by RT-qPCR and a western blot analysis. After the shRNA-BMI-1 plasmid was transfected into the GIST882 cells and nude mice, a cell counting kit-8 (CCK-8) assay and flow cytometry were utilized to detect the GIST882 cell proliferation, the apoptosis rate and the cell cycle. Tumor growth was observed by tumor xenograft in nude mice. Telomerase activity and telomere length were detected by a Southern blot and a target region amplified polymorphism. The shRNA-BMI-1 recombinant plasmid was successfully constructed. The mRNA and protein expression of the BMI-1 gene in GIST882 cells was suppressed by the shRNA-BMI-1 recombinant plasmid. Meanwhile, BMI-1 gene silencing inhibited the cell proliferation, tumor growth, and cell cycle in the GIST882 cells. However, cell apoptosis was increased and telomerase activity was decreased with the silencing of the BMI-1 gene. Collectively, the results of this study suggest that silencing the BMI-1 gene may provide a new target for the treatment of GISTs.
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Affiliation(s)
- Xin Wang
- Department of General Surgery, Chongqing General Hospital (Zhongshan Branch), Chongqing, PR China.
| | - Kun Wu
- Department of General Surgery, Chongqing General Hospital (Zhongshan Branch), Chongqing, PR China
| | - Lin-Kang Xiao
- Department of General Surgery, Chongqing General Hospital (Zhongshan Branch), Chongqing, PR China
| | - Xing-Ye Wu
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
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11
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BMI1 Roles in Cancer Stem Cells and Its Association with MicroRNAs Dysregulation in Cancer: Emphasis on Colorectal Cancer. INTERNATIONAL JOURNAL OF CANCER MANAGEMENT 2018. [DOI: 10.5812/ijcm.82926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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12
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Vashishtha V, Jinghan N, K.Yadav A. Antagonistic role of GSK3 isoforms in glioma survival. J Cancer 2018; 9:1846-1855. [PMID: 29805711 PMCID: PMC5968773 DOI: 10.7150/jca.21248] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/19/2017] [Indexed: 12/25/2022] Open
Abstract
GSK3 (Glycogen Synthase Kinase-3) function in brain is contributed by two distinct gene GSK3 alpha and GSK3 beta. Present findings indicate that imbalance in between GSK3 alpha and beta isoform contributes oncogenesis. In gliomas, GSK3 isoform specific functions are different then as reported for melanoma, prostate cancer, lung cancer etc. Both the isoforms of GSK3 are inversely regulating hnRNPA1 (RNA binding protein) expression, subsequently affecting RNA alternative splicing (BIN1, RON, Mcl1, PKM) in gliomas. Elevated expression of c-Myc, hnRNPA1, Phospo-ERK1/2 and Cyclin D1 in GSK3 alpha knock down cells, resembles GSK3 beta isoform overexpressing glioma cells, promotes cell survival. HnRNPA1 dependent survival signaling pathway were elaborated using si RNA approach or by over expressing cloned hnRNPA1 gene in U87 glioma cells. Therefore, performed study empirically support GSK3β inhibition along with restoration of GSK3α would be a good strategy to target gliomas.
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Affiliation(s)
| | | | - Ajay K.Yadav
- Cancer Genetics Laboratory, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi (North Campus), Delhi- 110007, India
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13
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Recombinant TAT-BMI-1 fusion protein induces ex vivo expansion of human umbilical cord blood-derived hematopoietic stem cells. Oncotarget 2018; 8:43782-43798. [PMID: 28187462 PMCID: PMC5546440 DOI: 10.18632/oncotarget.15156] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/17/2017] [Indexed: 01/24/2023] Open
Abstract
Transplantation of hematopoietic stem cells (HSCs) is a well-established therapeutic approach for numerous disorders. HSCs are typically derived from bone marrow or peripheral blood after cytokine-induced mobilization. Umbilical cord blood (CB) represents an appealing alternative HSC source, but the small amounts of the individual CB units have limited its applications. The availability of strategies for safe ex vivo expansion of CB-derived HSCs (CB-HSCs) may allow to extend the use of these cells in adult patients and to avoid the risk of insufficient engraftment or delayed hematopoietic recovery. Here we describe a system for the ex vivo expansion of CB-HSCs based on their transient exposure to a recombinant TAT-BMI-1 chimeric protein. BMI-1 belongs to the Polycomb family of epigenetic modifiers and is recognized as a central regulator of HSC self-renewal. Recombinant TAT-BMI-1 produced in bacteria was able to enter the target cells via the HIV TAT-derived protein transduction peptide covalently attached to BMI-1, and conserved its biological activity. Treatment of CB-CD34+ cells for 3 days with repeated addition of 10 nM purified TAT-BMI-1 significantly enhanced total cell expansion as well as that of primitive hematopoietic progenitors in culture. Importantly, TAT-BMI-1-treated CB-CD34+ cells displayed a consistently higher rate of multi-lineage long-term repopulating activity in primary and secondary xenotransplants in immunocompromised mice. Thus, recombinant TAT-BMI-1 may represent a novel, effective reagent for ex vivo expansion of CB-HSC for therapeutic purposes.
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14
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Dimri M, Kang M, Dimri GP. A miR-200c/141-BMI1 autoregulatory loop regulates oncogenic activity of BMI1 in cancer cells. Oncotarget 2017; 7:36220-36234. [PMID: 27105531 PMCID: PMC5094995 DOI: 10.18632/oncotarget.8811] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/31/2016] [Indexed: 12/21/2022] Open
Abstract
MicroRNAs (miRNAs) are known to function as oncomiRs or tumor suppressors and are important noncoding RNA regulators of oncogenesis. The miR-200c/141 locus on chromosome 12 encodes miR-200c and miR-141, two members of the miR-200 family, which have been shown to function as tumor suppressive miRNAs by targeting multiple oncogenic factors such as polycomb group protein BMI1. Here, we show that BMI1 reciprocally functions as a transcriptional repressor of the miR-200c/141 cluster and that BMI1 inhibitors upregulate expression of miR-200c and miR-141. Our data suggest that BMI1 binds to the miR-200c/141 promoter and regulates it through transcription factor binding motifs E-box 2 and Z-box 1 to repress expression of miR-200c/141 cluster. We also show that PTC-209, a small molecule inhibitor of BMI1 gene expression induces cellular senescence and transcriptionally upregulates expression of miR-200c/141 cluster in breast cancer cells. Furthermore, inhibition of expression of miR-200c or miR-141 overcomes tumor suppressive effects of PTC-209 including induction of cellular senescence and downregulation of breast cancer stem cell phenotype. Therefore, our studies suggest a reciprocal regulation between BMI1 and miR-200c/141 cluster, and that BMI1 inhibitory drugs can further amplify their inhibitory effects on BMI1 via multiple mechanisms including posttranscriptional regulation by upregulating BMI1 targeting miRNAs.
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Affiliation(s)
- Manjari Dimri
- Department of Biochemistry and Molecular Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Mingu Kang
- Department of Biochemistry and Molecular Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Goberdhan P Dimri
- Department of Biochemistry and Molecular Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
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15
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Wang Q, Li Z, Wu Y, Huang R, Zhu Y, Zhang W, Wang Y, Cheng J. Pharmacological inhibition of Bmi1 by PTC-209 impaired tumor growth in head neck squamous cell carcinoma. Cancer Cell Int 2017; 17:107. [PMID: 29200967 PMCID: PMC5697105 DOI: 10.1186/s12935-017-0481-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/16/2017] [Indexed: 12/12/2022] Open
Abstract
Background Bmi1 (B lymphoma Mo-MLV insertion region 1 homolog) contributes to human tumorigenesis via epigenetic transcriptional silencing and represents a novel therapeutic target with great potentials. Here we sought to determine the therapeutic efficiency of PTC-209, a potent and selective Bmi1 inhibitor, in head neck squamous cell carcinoma (HNSCC) cells and a HNSCC xenograft model. Methods The mutation pattern, mRNA level of Bmi1 in HNSCC and its associations with clinicopathological parameters were determined through comprehensive data mining and interrogation using publicly available databases GENT, cBioPortal, Oncomine and TCGA. The PTC-209, a selective and potent Bmi1 inhibitor, was exploited and its effect on Bmi1 expression was measured in two HNSCC cell lines Cal27 and FaDu. The phenotypical changes of HNSCC cells were observed upon PTC-209 treatment in vitro. Moreover, the therapeutic effects of PTC-209 for HNSCC were determined in a xenograft animal model. Results Through comprehensive data mining and interrogation, we found that Bmi1 mRNA was frequently overexpressed in a subset of HNSCC samples. Our data revealed that PTC-209 robustly reduced the expression of Bmi1 in Cal27 and FaDu cells presumably by post-transcriptional repression and ubiquitin-proteasomal degradation. PTC-209 treatment resulted in impaired cell proliferation, G1-phase cell cycle arrest, compromised migration and invasiveness, and increased cell apoptosis and chemosensitivity to 5-FU and cisplatin in vitro. Moreover, PTC-209 exposure reduced colony formation, tumorsphere formation and the percentage of ALDH1+ subpopulation in both Cal27 and FaDu cells. Importantly, in vivo PTC-209 administration significantly reduced tumor growth in a HNSCC xenograft model probably by Bmi1 inhibition and impaired cell proliferation. Conclusions Our findings indicate that pharmacological inhibition of Bmi1 is a novel therapeutic strategy for HNSCC patients, especially with those with aberrant Bmi1 overexpression. Electronic supplementary material The online version of this article (10.1186/s12935-017-0481-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qiong Wang
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Zhongwu Li
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Yaping Wu
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China.,Department of Oral and Maxillofacial Surgery, Affiliated Stomatological Hospital, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Rong Huang
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China.,Department of Oral and Maxillofacial Surgery, Affiliated Stomatological Hospital, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Yumin Zhu
- Department of Oral and Maxillofacial Surgery, Affiliated Stomatological Hospital, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Wei Zhang
- Department of Oral Pathology, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Yanling Wang
- Department of Oral Pathology, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Jie Cheng
- Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China.,Department of Oral Pathology, School of Stomatology, Nanjing Medical University, 136 Hanzhong Road, Nanjing, 210029 Jiangsu China
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16
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O-GlcNAcylation modulates Bmi-1 protein stability and potential oncogenic function in prostate cancer. Oncogene 2017; 36:6293-6305. [PMID: 28714959 DOI: 10.1038/onc.2017.223] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 12/14/2022]
Abstract
The Polycomb group transcriptional repressor Bmi-1 often overexpressed and participated in stem cells self-renewal and tumorigenesis initiating of prostate cancer. In this progression, Bmi-1 protein was regulated by transcription and post-translational modifications (PTMs). Nobly, the underlying PTMs regulation of Bmi-1 is poorly known. Here we use co-immunoprecipitation show that in C4-2 cell line, Bmi-1 directly interacted with OGT which is the only known enzyme catalyzed the O-GlcNAcylation in human. Furthermore, we identified that Ser255 is the site for Bmi-1 O-GlcNAcylation, and O-GlcNAcylation promoted Bmi-1 protein stability and its oncogenic activity. Finally, microarray analysis has characterized potential oncogenes associated pathway subject to repression via the OGT-Bmi-1 axis. Taken together, these results indicate that OGT-mediated O-GlcNAcylation at Ser255 stabilizes Bmi-1 and hence inhibits the TP53, PTEN and CDKN1A/CDKN2A pathway. The study not only uncovers a novel functional PTMs of Bmi-1 but also reveals a unique oncogenic role of O-GlcNAcylation in prostate cancer.
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17
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Li LU, Zhao Y, Zhang H. P16INK4a upregulation mediated by TBK1 induces retinal ganglion cell senescence in ischemic injury. Cell Death Dis 2017; 8:e2752. [PMID: 28425986 PMCID: PMC5477587 DOI: 10.1038/cddis.2017.169] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/13/2017] [Accepted: 03/20/2017] [Indexed: 12/13/2022]
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide that is characterized by progressive retinal ganglion cell (RGC) death. However, RGC senescence as a phase before RGC death, and the mechanism of RGC senescence remains unclear. Here, we demonstrate that TANK-binding protein 1 (TBK1) is upregulated in acute IOP elevation-induced ischemic retinas mouse model. Moreover, pre-treatment with the TBK1 inhibitor BX-795 reduced p16INK4a (p16) expression and RGC senescence. Upregulation of TBK1 via plasmid transfection increased Akt phosphorylation at Ser473 and Bmi1 phosphorylation. The Akt inhibitor MK-2206 decreased the expression of p16 and Bmi1 serine phosphorylation. A Bmi1 Ser316 mutation also attenuated TBK1-induced p16 upregulation. Finally, silencing of TBK1 via shRNA knockdown reduced the expression of p16 as well as Akt and Bmi1 phosphorylation, reducing RGC senescence in vivo. These data suggest that acute IOP elevation-induced ischemia increases TBK1 expression, which then increases p16 expression through the Akt- Bmi1 phosphorylation pathway. This study therefore elucidates a novel mechanism whereby TBK1 regulates p16 expression and RGC senescence, suggesting a potential novel treatment strategy for minimizing RGC senescence in retinal ischemia and glaucoma.
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Affiliation(s)
- L U Li
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Ophthalmology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, People's Republic of China
| | - Yin Zhao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Zhang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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18
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Banerjee Mustafi S, Chakraborty PK, Dwivedi SKD, Ding K, Moxley KM, Mukherjee P, Bhattacharya R. BMI1, a new target of CK2α. Mol Cancer 2017; 16:56. [PMID: 28270146 PMCID: PMC5341428 DOI: 10.1186/s12943-017-0617-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/20/2017] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The polycomb group protein, BMI1 plays important roles in chromatin modification, stem cell function, DNA damage repair and mitochondrial bioenergetics. Such diverse cellular functions of BMI1 could be, in part, due to post-translational modifications, especially phosphorylation. To date, AKT has been reported as a kinase that by site specific phosphorylation of BMI1 modulates its oncogenic functions. METHODS Immunoprecipitation in conjunction with kinase assay and mass spectrometry was used to determine association with and site specific phosphorylation of BMI1 by CK2α. Functional implications of the BMI1/CK2α axis was examined in cancer cells utilizing siRNA and exogenous gene expression followed by biochemical and phenotypic studies. Correlations between expression of CK2α and BMI1 were determined from cell lines and formalin fixed paraffin embedded tissues representing the normal fallopian tube epithelium and high grade serous ovarian cancer samples. RESULTS Here we report that CK2α, a nuclear serine threonine kinase, phosphorylates BMI1 at Serine 110 as determined by in-vitro/ex-vivo kinase assay and mass spectrometry. In ovarian cancer cell lines, expression of CK2α correlated with the phospho-species, as well as basal BMI1 levels. Preventing phosphorylation of BMI1 at Serine 110 significantly decreased half-life and stability of the protein. Additionally, re-expression of the phosphorylatable but not non-phosphorylatable BMI1 rescued clonal growth in endogenous BMI1 silenced cancer cells leading us to speculate that CK2α-mediated phosphorylation stabilizes BMI1 and promotes its oncogenic function. Clinically, compared to normal fallopian tube epithelial tissues, the expression of both BMI1 and CK2α were significantly higher in tumor tissues obtained from high-grade serous ovarian cancer patients. Among tumor samples, the expression of BMI1 and CK2α positively correlated (Spearman coefficient = 0.62, P = 0.0021) with each other. CONCLUSION Taken together, our findings establish an important regulatory role of CK2α on BMI1 phosphorylation and stability and implicate the CK2α/BMI1 axis in ovarian cancer.
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Affiliation(s)
- Soumyajit Banerjee Mustafi
- Peggy and Charles Stephenson Cancer Center (OUHSC), University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1409B, Oklahoma City, OK 73104 USA
- Department of Obstetrics and Gynecology, University of Oklahoma Health Science Center, Oklahoma City, OK USA
| | - Prabir Kumar Chakraborty
- Peggy and Charles Stephenson Cancer Center (OUHSC), University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1409B, Oklahoma City, OK 73104 USA
- Department of Pathology, University of Oklahoma Health Science Center, Oklahoma City, OK USA
| | - Shailendra Kumar Dhar Dwivedi
- Peggy and Charles Stephenson Cancer Center (OUHSC), University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1409B, Oklahoma City, OK 73104 USA
- Department of Obstetrics and Gynecology, University of Oklahoma Health Science Center, Oklahoma City, OK USA
| | - Kai Ding
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Katherine M. Moxley
- Peggy and Charles Stephenson Cancer Center (OUHSC), University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1409B, Oklahoma City, OK 73104 USA
- Department of Obstetrics and Gynecology, University of Oklahoma Health Science Center, Oklahoma City, OK USA
| | - Priyabrata Mukherjee
- Peggy and Charles Stephenson Cancer Center (OUHSC), University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1409B, Oklahoma City, OK 73104 USA
- Department of Pathology, University of Oklahoma Health Science Center, Oklahoma City, OK USA
| | - Resham Bhattacharya
- Peggy and Charles Stephenson Cancer Center (OUHSC), University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1409B, Oklahoma City, OK 73104 USA
- Department of Obstetrics and Gynecology, University of Oklahoma Health Science Center, Oklahoma City, OK USA
- Department of Cell Biology, University of Oklahoma College of Medicine, Oklahoma City, OK USA
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19
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Gray F, Cho HJ, Shukla S, He S, Harris A, Boytsov B, Jaremko Ł, Jaremko M, Demeler B, Lawlor ER, Grembecka J, Cierpicki T. BMI1 regulates PRC1 architecture and activity through homo- and hetero-oligomerization. Nat Commun 2016; 7:13343. [PMID: 27827373 PMCID: PMC5105191 DOI: 10.1038/ncomms13343] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/26/2016] [Indexed: 12/21/2022] Open
Abstract
BMI1 is a core component of the polycomb repressive complex 1 (PRC1) and emerging data support a role of BMI1 in cancer. The central domain of BMI1 is involved in protein-protein interactions and is essential for its oncogenic activity. Here, we present the structure of BMI1 bound to the polyhomeotic protein PHC2 illustrating that the central domain of BMI1 adopts an ubiquitin-like (UBL) fold and binds PHC2 in a β-hairpin conformation. Unexpectedly, we find that the UBL domain is involved in homo-oligomerization of BMI1. We demonstrate that both the interaction of BMI1 with polyhomeotic proteins and homo-oligomerization via UBL domain are necessary for H2A ubiquitination activity of PRC1 and for clonogenic potential of U2OS cells. Here, we also emphasize need for joint application of NMR spectroscopy and X-ray crystallography to determine the overall structure of the BMI1-PHC2 complex.
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Affiliation(s)
- Felicia Gray
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Hyo Je Cho
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Shirish Shukla
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Shihan He
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ashley Harris
- Translational Oncology Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bohdan Boytsov
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Łukasz Jaremko
- Deutsches Zentrum fur Neurodegenerative Erkrankungen (DZNE), Am Fassberg 11, 37077 Goettingen, Germany
- Max-Planck Institute of Biophysical Chemistry, NMR-based Department for Structural Biology, Am Fassberg 11, 37077 Goettingen, Germany
| | - Mariusz Jaremko
- Max-Planck Institute of Biophysical Chemistry, NMR-based Department for Structural Biology, Am Fassberg 11, 37077 Goettingen, Germany
| | - Borries Demeler
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA
| | - Elizabeth R. Lawlor
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Translational Oncology Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jolanta Grembecka
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Tomasz Cierpicki
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
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20
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Sahasrabuddhe AA. BMI1: A Biomarker of Hematologic Malignancies. BIOMARKERS IN CANCER 2016; 8:65-75. [PMID: 27168727 PMCID: PMC4859448 DOI: 10.4137/bic.s33376] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/10/2016] [Accepted: 04/13/2016] [Indexed: 02/06/2023]
Abstract
BMI1 oncogene is a catalytic member of epigenetic repressor polycomb group proteins. It plays a critical role in the regulation of gene expression pattern and consequently several cellular processes during development, including cell cycle progression, senescence, aging, apoptosis, angiogenesis, and importantly self-renewal of adult stem cells of several lineages. Preponderance of evidences indicates that deregulated expression of PcG protein BMI1 is associated with several human malignancies, cancer stem cell maintenance, and propagation. Importantly, overexpression of BMI1 correlates with therapy failure in cancer patients and tumor relapse. This review discusses the diverse mode of BMI1 regulation at transcriptional, posttranscriptional, and posttranslational levels as well as at various critical signaling pathways regulated by BMI1 activity. Furthermore, this review highlights the role of BMI1 as a biomarker and therapeutic target for several subtypes of hematologic malignancies and the importance to target this biomarker for therapeutic applications.
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Affiliation(s)
- Anagh A Sahasrabuddhe
- Department of Biotechnology, Pandit Ravishankar Shukla University, Chhattisgarh, India
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21
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Wang SS, Jiang J, Liang XH, Tang YL. Links between cancer stem cells and epithelial-mesenchymal transition. Onco Targets Ther 2015; 8:2973-80. [PMID: 26527883 PMCID: PMC4621173 DOI: 10.2147/ott.s91863] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The epithelial-mesenchymal transition (EMT) has been reported to be an important program that is often activated during the process of cancer invasion and metastasis. Cancer stem cells (CSCs) that can initiate and maintain cancer are also involved in invasion and metastasis of cancer. Recently, insights into the molecular mechanisms and functional features of mesenchymal cells have been greatly colored by findings that some of them have been endowed with the self-renewal trait associated with normal tissue stem cells and CSCs. Among cancer cells experiencing EMT, only some of the most competent CSCs will succeed in planting in another organ. In this paper, we review the molecular mechanism behind the link of EMT and CSCs in cancer progression.
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Affiliation(s)
- Sha-Sha Wang
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, People's Republic of China ; Department of Oral and Maxillofacial Surgery, Sichuan University, Chengdu, People's Republic of China
| | - Jian Jiang
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, People's Republic of China ; Department of Oral and Maxillofacial Surgery, Sichuan University, Chengdu, People's Republic of China
| | - Xin-Hua Liang
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, People's Republic of China ; Department of Oral and Maxillofacial Surgery, Sichuan University, Chengdu, People's Republic of China
| | - Ya-Ling Tang
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, People's Republic of China ; Department of Oral Pathology, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
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22
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Balasubramanian S, Scharadin TM, Han B, Xu W, Eckert RL. The Bmi-1 helix-turn and ring finger domains are required for Bmi-1 antagonism of (-) epigallocatechin-3-gallate suppression of skin cancer cell survival. Cell Signal 2015; 27:1336-44. [PMID: 25843776 PMCID: PMC4756650 DOI: 10.1016/j.cellsig.2015.03.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/18/2015] [Accepted: 03/21/2015] [Indexed: 01/01/2023]
Abstract
The Bmi-1 Polycomb group (PcG) protein is an important epigenetic regulator of chromatin status. Elevated Bmi-1 expression is observed in skin cancer and contributes to cancer cell survival. (-) Epigallocatechin-3-gallate (EGCG), an important green tea-derived cancer prevention agent, reduces Bmi-1 level resulting in reduced skin cancer cell survival. This is associated with increased p21(Cip1) and p27(Kip1) expression, reduced cyclin, and cyclin dependent kinase expression, and increased cleavage of apoptotic markers. These EGCG-dependent changes are attenuated by vector-mediated maintenance of Bmi-1 expression. In the present study, we identify Bmi-1 functional domains that are required for this response. Bmi-1 expression reverses the EGCG-dependent reduction in SCC-13 cell survival, but Bmi-1 mutants lacking the helix-turn-helix-turn-helix-turn (Bmi-1ΔHT) or ring finger (Bmi-1ΔRF) domains do not reverse the EGCG impact. The reduction in Ring1B ubiquitin ligase activity, observed in the presence of mutant Bmi-1, is associated with reduced ability of these mutants to interact with and activate Ring1B ubiquitin ligase, the major ligase responsible for the ubiquitination of histone H2A during chromatin condensation. This results in less chromatin condensation leading to increased tumor suppressor gene expression and reduced cell survival; thereby making the cells more susceptible to the anti-survival action of EGCG. We further show that these mutants act in a dominant-negative manner to inhibit the action of endogenous Bmi-1. Our results suggest that the HT and RF domains are required for Bmi-1 ability to maintain skin cancer cell survival in response to cancer preventive agents.
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Affiliation(s)
| | - Tiffany M Scharadin
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Bingshe Han
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Wen Xu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Richard L Eckert
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Dermatology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.
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23
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Bhattacharya R, Mustafi SB, Street M, Dey A, Dwivedi SKD. Bmi-1: At the crossroads of physiological and pathological biology. Genes Dis 2015; 2:225-239. [PMID: 26448339 PMCID: PMC4593320 DOI: 10.1016/j.gendis.2015.04.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bmi-1 is a member of the Polycomb repressor complex 1 that mediates gene silencing by regulating chromatin structure and is indispensable for self-renewal of both normal and cancer stem cells. Despite three decades of research that have elucidated the transcriptional regulation, post-translational modifications and functions of Bmi-1 in regulating the DNA damage response, cellular bioenergetics, and pathologies, the entire potential of a protein with such varied functions remains to be realized. This review attempts to synthesize the current knowledge on Bmi-1 with an emphasis on its role in both normal physiology and cancer. Additionally, since cancer stem cells are emerging as a new paradigm for therapy resistance, the role of Bmi-1 in this perspective is also highlighted. The wide spectrum of malignancies that implicate Bmi-1 as a signature for stemness and oncogenesis also make it a suitable candidate for therapy. Nonetheless, new approaches are vitally needed to further characterize physiological roles of Bmi-1 with the long-term goal of using Bmi-1 as a prognostic marker and a therapeutic target.
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Affiliation(s)
- Resham Bhattacharya
- Department of Obstetrics and Gynecology, Stephenson Cancer Center, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, United States of America
| | - Soumyajit Banerjee Mustafi
- Department of Obstetrics and Gynecology, Stephenson Cancer Center, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, United States of America
| | - Mark Street
- Department of Obstetrics and Gynecology, Stephenson Cancer Center, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, United States of America
| | - Anindya Dey
- Department of Obstetrics and Gynecology, Stephenson Cancer Center, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, United States of America
| | - Shailendra Kumar Dhar Dwivedi
- Department of Obstetrics and Gynecology, Stephenson Cancer Center, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, United States of America
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24
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Oncogenic Y641 mutations in EZH2 prevent Jak2/β-TrCP-mediated degradation. Oncogene 2014; 34:445-54. [PMID: 24469040 DOI: 10.1038/onc.2013.571] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/14/2013] [Accepted: 12/03/2013] [Indexed: 12/16/2022]
Abstract
EZH2 (enhancer of zeste homolog 2) is a critical enzymatic subunit of the polycomb repressive complex 2 (PRC2), which trimethylates histone H3 (H3K27) to mediate gene repression. Somatic mutations, overexpression and hyperactivation of EZH2 have been implicated in the pathogenesis of several forms of cancer. In particular, recurrent gain-of-function mutations targeting EZH2 Y641 occur most frequently in follicular lymphoma and aggressive diffuse large B-cell lymphoma and are associated with H3K27me3 hyperactivation, which contributes to lymphoma pathogenesis. However, the post-translational mechanisms of EZH2 regulation are not completely understood. Here we show that EZH2 is a novel interactor and substrate of the SCF E3 ubiquitin ligase β-TrCP (FBXW1). β-TrCP ubiquitinates EZH2 and Jak2-mediated phosphorylation on Y641 directs β-TrCP-mediated EZH2 degradation. RNA interference-mediated silencing of β-TrCP or inhibition of Jak2 results in EZH2 stabilization with attendant increase in H3K27 trimethylation activity. Importantly, the EZH2(Y641) mutants recurrently implicated in lymphoma pathogenesis are unable to bind β-TrCP. Further, endogenous EZH2(Y641) mutants in lymphoma cells exhibit increased EZH2 stability and H3K27me3 hyperactivity. Our studies demonstrate that β-TrCP has an important role in controlling H3K27 trimethylation activity and lymphoma pathogenesis by targeting EZH2 for degradation.
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25
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Minamide R, Fujiwara K, Hasegawa K, Yoshikawa K. Antagonistic interplay between necdin and Bmi1 controls proliferation of neural precursor cells in the embryonic mouse neocortex. PLoS One 2014; 9:e84460. [PMID: 24392139 PMCID: PMC3879318 DOI: 10.1371/journal.pone.0084460] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 11/21/2013] [Indexed: 01/07/2023] Open
Abstract
Neural precursor cells (NPCs) in the neocortex exhibit a high proliferation capacity during early embryonic development and give rise to cortical projection neurons after maturation. Necdin, a mammal-specific MAGE (melanoma antigen) family protein that possesses anti-mitotic and pro-survival activities, is expressed abundantly in postmitotic neurons and moderately in tissue-specific stem cells or progenitors. Necdin interacts with E2F transcription factors and suppresses E2F1-dependent transcriptional activation of the cyclin-dependent kinase Cdk1 gene. Here we show that necdin serves as a suppressor of NPC proliferation in the embryonic neocortex. Necdin is moderately expressed in the ventricular zone of mouse embryonic neocortex, in which proliferative cell populations are significantly increased in necdin-null mice. In the neocortex of necdin-null embryos, expression of Cdk1 and Sox2, a stem cell marker, is significantly increased, whereas expression of p16, a cyclin-dependent kinase inhibitor, is markedly diminished. Cdk1 and p16 expression levels are also significantly increased and decreased, respectively, in primary NPCs prepared from necdin-null embryos. Intriguingly, necdin interacts directly with Bmi1, a Polycomb group protein that suppresses p16 expression and promotes NPC proliferation. In HEK293A cells transfected with luciferase reporter constructs, necdin relieves Bmi1-dependent repression of p16 promoter activity, whereas Bmi1 counteracts necdin-mediated repression of E2F1-dependent Cdk1 promoter activity. In lentivirus-infected primary NPCs, necdin overexpression increases p16 expression, suppresses Cdk1 expression, and inhibits NPC proliferation, whereas Bmi1 overexpression suppresses p16 expression, increases Cdk1 expression, and promotes NPC proliferation. Our data suggest that embryonic NPC proliferation in the neocortex is regulated by the antagonistic interplay between necdin and Bmi1.
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Affiliation(s)
- Ryohei Minamide
- Laboratory of Regulation of Neuronal Development, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Kazushiro Fujiwara
- Laboratory of Regulation of Neuronal Development, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Koichi Hasegawa
- Laboratory of Regulation of Neuronal Development, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Kazuaki Yoshikawa
- Laboratory of Regulation of Neuronal Development, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
- * E-mail:
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26
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Wang HB, Liu GH, Zhang H, Xing S, Hu LJ, Zhao WF, Xie B, Li MZ, Zeng BH, Li Y, Zeng MS. Sp1 and c-Myc regulate transcription ofBMI1in nasopharyngeal carcinoma. FEBS J 2013; 280:2929-44. [PMID: 23601184 DOI: 10.1111/febs.12299] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/15/2013] [Accepted: 04/18/2013] [Indexed: 10/26/2022]
Affiliation(s)
| | - Gui-Hong Liu
- Department of Oncology; the Second Affiliated Hospital of Guangzhou Medical College; Guangzhou; China
| | | | - Shan Xing
- State Key Laboratory of Oncology in South China; Sun Yat-sesn University Cancer Center; Guangzhou; China
| | | | - Wei-Feng Zhao
- State Key Laboratory of Oncology in South China; Sun Yat-sesn University Cancer Center; Guangzhou; China
| | - Bo Xie
- Zhongshan School of Medicine; Sun Yat-Sen University; Guangzhou; China
| | | | - Bo-Hang Zeng
- Department of Oncology; the Second Affiliated Hospital of Guangzhou Medical College; Guangzhou; China
| | - Yingqiu Li
- State Key Laboratory of Biocontrol; School of Life Sciences; Sun Yat-sen University; Guangzhou; China
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27
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Cho JH, Dimri M, Dimri GP. A positive feedback loop regulates the expression of polycomb group protein BMI1 via WNT signaling pathway. J Biol Chem 2012; 288:3406-18. [PMID: 23239878 DOI: 10.1074/jbc.m112.422931] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Polycomb group protein BMI1 plays an important role in cellular homeostasis by maintaining a balance between proliferation and senescence. It is often overexpressed in cancer cells and is required for self-renewal of stem cells. At present, very little is known about the signaling pathways that regulate the expression of BMI1. Here, we report that BMI1 autoactivates its own promoter via an E-box present in its promoter. We show that BMI1 acts as an activator of the WNT pathway by repressing Dickkopf (DKK) family of WNT inhibitors. BMI1 mediated repression of DKK proteins; in particular, DKK1 led to up-regulation of WNT target c-Myc, which in turn further led to transcriptional autoactivation of BMI1. Thus, a positive feedback loop connected by the WNT signaling pathway regulates BMI1 expression. This positive feedback loop regulating BMI1 expression may be relevant to the role of BMI1 in promoting cancer and maintaining stem cell phenotype.
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Affiliation(s)
- Joon-Ho Cho
- Department of Biochemistry and Molecular Biology, The George Washington University Medical Center, Washington, DC 20037, USA
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28
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Cao L, Bombard J, Cintron K, Sheedy J, Weetall ML, Davis TW. BMI1 as a novel target for drug discovery in cancer. J Cell Biochem 2012; 112:2729-41. [PMID: 21678481 DOI: 10.1002/jcb.23234] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Growing evidence has demonstrated that clonogenic cancer stem (initiating) cells are responsible for tumor regrowth and disease relapse. Bmi-1 plays a critical role in the self-renewal of adult stem cells. The Bmi-1 protein is elevated in many types of cancers, and experimental reduction of Bmi-1 protein levels by small interfering RNA (siRNA) causes apoptosis and/or senescence in tumor cells in vitro and increases susceptibility to cytotoxic agents. The Bmi-1 protein has no known enzymatic activity, but serves as the key regulatory component of the PRC1 complex (polycomb repressive complex-1). This complex influences chromatin structure and regulates transcriptional activity of a number of important loci including the Ink4a locus which encodes the tumor suppressor proteins p16(Ink4a) and p14(Arf) . In this prospective study, we will discuss the implication of BMI1 in cancers, the biology of BMI1, and the regulatory control of BMI1 expression. The target validation and the future prospects of targeting BMI1 in cancer therapy are also discussed.
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Affiliation(s)
- Liangxian Cao
- PTC Therapeutics, Inc., South Plainfield, New Jersey, New Jersey 07080, USA.
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29
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Sahasrabuddhe AA, Dimri M, Bommi PV, Dimri GP. βTrCP regulates BMI1 protein turnover via ubiquitination and degradation. Cell Cycle 2011; 10:1322-30. [PMID: 21430439 DOI: 10.4161/cc.10.8.15372] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The polycomb group protein BMI1 has been linked to proliferation, senescence, cancer progression and stem cell phenotype. At present, very little is known about its regulation. Here, we report that BMI1 contains a functional recognition motif for the F box protein βTrCP, which regulates ubiquitination and proteasome-mediated degradation of various proteins. We show that overexpression of wild-type βTrCP but not the ΔF mutant of it promotes BMI1 ubiquitination and degradation, and knockdown of βTrCP results in increased expression of BMI1. Furthermore, a mutant of BMI1 with an altered βTrCP recognition motif is much more stable than wild-type BMI1. We also show that wild-type BMI1 but not the mutant BMI1 interacts with βTrCP. Accordingly, compared to wild-type BMI1, mutant protein exhibited increased pro-oncogenic activity. In summary, our findings suggest that βTrCP regulates turnover of BMI1 and its function relevant to oncogenesis, cellular senescence and aging.
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Affiliation(s)
- Anagh A Sahasrabuddhe
- Department of Medicine, NorthShore University HealthSystem Research Institute, Evanston, IL, USA
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