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Woytinek K, Glitscher M, Hildt E. Antagonism of epidermal growth factor receptor signaling favors hepatitis E virus life cycle. J Virol 2024; 98:e0058024. [PMID: 38856640 PMCID: PMC11265270 DOI: 10.1128/jvi.00580-24] [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] [Received: 04/24/2024] [Accepted: 05/09/2024] [Indexed: 06/11/2024] Open
Abstract
Hepatitis E virus (HEV) poses a global threat, which currently remains understudied in terms of host interactions. Epidermal growth factor receptor (EGFR) plays multifaceted roles in viral pathogenesis, impacting host-cell entry, viral replication, and host-defense modulation. On the one hand, EGFR signaling emerged as a major driver in innate immunity; on the other hand, a crosstalk between HEV and EGFR requires deeper analysis. We therefore aimed to dissect the receptor's involvement in the HEV life cycle. In persistently HEV-infected cells, the EGFR amount is decreased alongside with enhanced receptor internalization. As compared with the control ligand-induced EGFR, activation revealed an early receptor internalization and degradation in HEV-replicating cells, resulting in a notable EGFR signaling delay. Interestingly, inhibition or silencing of EGFR increased viral replication, extracellular and intracellular viral transcripts, and released infectious particles. The pro-viral impact of EGFR inhibition was attributed to (i) impaired expression of interferon-stimulated genes, (ii) activation of the autophagosomal system, (iii) virus-induced inhibition of lysosomal acidification, and (iv) a decrease of the cellular cholesterol level. IMPORTANCE This study identifies epidermal growth factor receptor (EGFR) as a novel host factor affecting hepatitis E virus (HEV): EGFR downregulation promotes viral replication, release, and evasion from the innate immune response. The discovery that EGFR inhibition favors viral spread is particularly concerning for HEV patients undergoing EGFR inhibitor treatment.
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Affiliation(s)
| | - Mirco Glitscher
- Division of Virology, Paul Ehrlich Institute, Langen, Germany
| | - Eberhard Hildt
- Division of Virology, Paul Ehrlich Institute, Langen, Germany
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2
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Zeng H, Wang W, Zhang L, Lin Z. HER3-targeted therapy: the mechanism of drug resistance and the development of anticancer drugs. CANCER DRUG RESISTANCE (ALHAMBRA, CALIF.) 2024; 7:14. [PMID: 38835349 PMCID: PMC11149107 DOI: 10.20517/cdr.2024.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 04/04/2024] [Accepted: 04/23/2024] [Indexed: 06/06/2024]
Abstract
Human epidermal growth factor receptor 3 (HER3), which is part of the HER family, is aberrantly expressed in various human cancers. Since HER3 only has weak tyrosine kinase activity, when HER3 ligand neuregulin 1 (NRG1) or neuregulin 2 (NRG2) appears, activated HER3 contributes to cancer development and drug resistance by forming heterodimers with other receptors, mainly including epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2). Inhibition of HER3 and its downstream signaling, including PI3K/AKT, MEK/MAPK, JAK/STAT, and Src kinase, is believed to be necessary to conquer drug resistance and improve treatment efficiency. Until now, despite multiple anti-HER3 antibodies undergoing preclinical and clinical studies, none of the HER3-targeted therapies are licensed for utilization in clinical cancer treatment because of their safety and efficacy. Therefore, the development of HER3-targeted drugs possessing safety, tolerability, and sensitivity is crucial for clinical cancer treatment. This review summarizes the progress of the mechanism of HER3 in drug resistance, the HER3-targeted therapies that are conducted in preclinical and clinical trials, and some emerging molecules that could be used as future designed drugs for HER3, aiming to provide insights for future research and development of anticancer drugs targeting HER3.
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Affiliation(s)
- Huilan Zeng
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Wei Wang
- Department of Cancer Center, Chongqing University Three Gorges Hospital, School of Medicine, Chongqing University, Chongqing 404000, China
| | - Lin Zhang
- Department of Gastroenterology, Chongqing University Jiangjin Hospital, Chongqing 402260, China
| | - Zhenghong Lin
- School of Life Sciences, Chongqing University, Chongqing 401331, China
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3
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Li KS, Zhu XD, Liu HD, Zhang SZ, Li XL, Xiao N, Liu XF, Xu B, Lei M, Zhang YY, Shi WK, Cao MQ, Xu YF, Tang ZY, Sun HC. NT5DC2 promotes tumor cell proliferation by stabilizing EGFR in hepatocellular carcinoma. Cell Death Dis 2020; 11:335. [PMID: 32382041 PMCID: PMC7206140 DOI: 10.1038/s41419-020-2549-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/07/2020] [Indexed: 02/07/2023]
Abstract
Most hepatocellular carcinoma (HCC) patients are diagnosed at an advanced stage; however, the effect of systemic therapy on advanced HCC remains undetermined. Therefore, new treatment targets must be identified. We analyzed Gene Expression Omnibus datasets from two HCC patient cohorts and found that NT5DC2 was associated with vascular invasion and poor survival. In two hepatoma cell lines, NT5DC2 overexpression promoted HCC cell proliferation and clone formation in vitro and promoted tumor growth in vivo. Coimmunoprecipitation assays and liquid chromatography with tandem mass spectrometry analysis revealed that NT5DC2 bound directly to epidermal growth factor receptor (EGFR). NT5DC2 upregulated EGFR expression by downregulating EGFR ubiquitination and preventing its degradation via the ubiquitin-proteasome pathway but did not upregulate its transcription. EGFR upregulation activated downstream signal transduction, which played a critical role in the protumor effects of NT5DC2. Erlotinib, a small-molecule inhibitor of EGFR, blocked the effect of NT5DC2 in promoting HCC cell proliferation. In a cohort of 79 patients who underwent curative resection for HCC, NT5DC2 expression in the tumors was associated with larger tumors and microvascular invasion. NT5DC2 expression was also independently associated with recurrence-free survival. The present study demonstrated for the first time that NT5DC2 promotes tumor cell proliferation in HCC and may serve as a potential molecular target for treating HCC. EGFR blockage could be used to treat selected patients with NT5DC2 upregulation.
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Affiliation(s)
- Kang-Shuai Li
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Xiao-Dong Zhu
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Hong-Da Liu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, 210029, Nanjing, Jiangsu province, China
| | - Shi-Zhe Zhang
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Xiao-Long Li
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Nan Xiao
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Xue-Feng Liu
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Bin Xu
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Ming Lei
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Yuan-Yuan Zhang
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Wen-Kai Shi
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Man-Qing Cao
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Yun-Fei Xu
- Department of General Surgery, Qilu Hospital of Shandong University, No. 107, Wenhua Xi Road, 250012, Jinan, China
| | - Zhao-You Tang
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China
| | - Hui-Chuan Sun
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 200032, Shanghai, China. .,Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, 200032, Shanghai, China.
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4
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Yang Q, Qiao X, Li D, Chen B, Zhang L, Yuan C, Lin H. Expression and association of IL-21, FBXL20 and tumour suppressor gene PTEN in laryngeal cancer. Saudi J Biol Sci 2019; 26:2048-2051. [PMID: 31889792 PMCID: PMC6923488 DOI: 10.1016/j.sjbs.2019.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 08/09/2019] [Accepted: 08/14/2019] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE To study the expression of three genes IL-21, FBXL20 and tumour suppressor gene PTEN in laryngeal cancer; analyse the differences in their expression in laryngeal cancer and adjacent tissues; by using pEGFP-N1-IL21 and pGPU/GFP/Neo-FBXL20 expression vectors, to analyse the characteristics in their expression in laryngeal cancer cells outside the body as well as the associations among them. METHODS The expression of the three genes in laryngeal cancer and adjacent tissues from 30 cases and in normal laryngeal tissues from 20 healthy persons was detected with the RT-PCR; laryngeal cancer cell line (HEp-2 cells) transfection was also performed with the pEGFP-N1-IL21 and pGPU/GFP/Neo-FBXL20 expression vectors we constructed, to detect the mRNA expression of the three genes. Cell proliferation, apoptosis and cell cycle were measured by the MTT assay. RESULTS The results of RT-PCR showed that the expression of IL-21 and FBXL20 was up-regulated in laryngeal cancer, while the expression of tumour suppressor gene PTEN was significantly decreased (p < 0.01). In HEp-2 cells transfected with pGPU/GFP/Neo-IL-21 and pGPU/GFP/Neo-FBXL20 expression vectors, the mRNA expression of PTEN was restored to some extent (p < 0.05); in addition, the ability of HEp-2 cells in proliferation and invasion was also reduced. CONCLUSIONS IL-21 and FBXL20 genes are important in the occurrence and development of laryngeal cancer; the expression of PTEN gene can suppress laryngeal cancer, and there's a certain association among IL-21, FBXL20 and PTEN.
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Affiliation(s)
- Qing Yang
- Department of Two Blood Transfusion, the First Hospital of Jilin University, Changchun 130000, China
| | - Xiaofeng Qiao
- Department of Otorhinolaryngology, Shanxi Provincial People’s Hospital Affiliated to Shanxi Medical University, Taiyuan 030001, China
| | - Daguang Li
- Department of Two Blood Transfusion, the First Hospital of Jilin University, Changchun 130000, China
| | - Bo Chen
- Department of Two Blood Transfusion, the First Hospital of Jilin University, Changchun 130000, China
| | - Lingmin Zhang
- Department of Two Blood Transfusion, the First Hospital of Jilin University, Changchun 130000, China
| | - Cuiling Yuan
- Department of Two Blood Transfusion, the First Hospital of Jilin University, Changchun 130000, China
| | - Hua Lin
- Department of Clinical Laboratory, the First Hospital of Jilin University, Changchun 130000, China
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5
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Zhang LZ, Qi WH, Zhao G, Liu LX, Xue H, Hu WX, Wang QQ, Li CS. Correlation between PTEN and P62 gene expression in rat colorectal cancer cell. Saudi J Biol Sci 2019; 26:1986-1990. [PMID: 31885487 PMCID: PMC6921302 DOI: 10.1016/j.sjbs.2019.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/06/2019] [Accepted: 08/08/2019] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE Autophagy is a cellular pathway that regulates the transportation and degradation of cytoplasmic macromolecules and organelles towards lysosome, which is often related to the tumorigenesis and tumor suppression. Here, we investigate the regulating effect of PTEN gene on autophagy-related protein P62 in rat colorectal cancer (CRC) cells and explore the application value of PTEN gene in clinic. METHODS Rat colorectal cancer was induced by intraperitoneal injection of 1,2-dimethyl hydrazine in male ACI rats. A total of 20 rats were randomly selected from those successfully induced with CRC as the experimental group, while 10 healthy rats as control. The rat CRC cells were isolated and cultured. After transfecting the rat CRC cells with pEGFP-N1-PTEN plasmid, RT-PCR was adopted to examine that gene expression of p62 and PTEN, while Western blotting was used to detect the protein expression of p62 and PTEN. Also, the proliferation of CRC cells was measured by MTT assay. RESULTS The expression of PTEN gene in the experimental group was significantly inhibited as compared with the control group, while the expression of P62 gene was significantly increased (p < 0.05). Western blotting demonstrated that the PTEN protein in the experimental group was lower, while the expression of P62 protein was higher. When the CRC cells were transfected with pEGFP-N1-PTEN plasmid, the PTEN expressions were elevated, while p62 was down-regulated. Also, the proliferation of CRC cells was inhibited. CONCLUSION The expression of PTEN gene is negatively correlated with the expression of P62 gene in rat CRC cells. And the expression of PTEN gene can inhibit the occurrence and development of colorectal cancer, thus providing theoretical basis for future clinical treatment.
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Affiliation(s)
- Li-ze Zhang
- Department of Anorectal, The Affiliated Hospital of Qingdao University, Qingdao 266555, China
| | - Wen-hai Qi
- Department of Anorectal Surgery, The Affiliated Hospital of Yan’an University, Yan’an 716000, China
| | - Gang Zhao
- Department of Anorectal, The Affiliated Hospital of Qingdao University, Qingdao 266555, China
| | - Lin-xun Liu
- Department of General Surgery, Qinghai Province People’s Hospital, Xining 410035, China
| | - Hui Xue
- Department of Gynecology, The Qingdao Hiser Hospital, Qingdao 266000, China
| | - Wen-xiu Hu
- Department of General Surgery, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, China
| | - Qian-qian Wang
- Department of Anorectal, Songshan Hospital of Qingdao University, Qingdao 266042, China
| | - Chun-sheng Li
- Gastrointestinal Colorectal and Anal Surgery, China-Japan Union Hospital of Jilin University, Changchun 130033, China
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6
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Huynh TK, Ho CY, Tsai CH, Wang CK, Chen YJ, Bau DT, Tu CY, Li TS, Huang WC. Proteasome Inhibitors Suppress ErbB Family Expression through HSP90-Mediated Lysosomal Degradation. Int J Mol Sci 2019; 20:ijms20194812. [PMID: 31569723 PMCID: PMC6801459 DOI: 10.3390/ijms20194812] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/19/2019] [Accepted: 09/21/2019] [Indexed: 12/31/2022] Open
Abstract
Although dual EGFR/HER2 tyrosine kinase inhibitor lapatinib has provided effective clinical benefits for HER2-positive breast cancer patients, acquired resistance to this drug remains a major concern. Thus, the development of alternative therapeutic strategies is urgently needed for patients who failed lapatinib treatment. Proteasome inhibitors have been reported to possess high anti-tumor activity to breast cancer cells. Therefore, this study aims to examine whether and how proteasome inhibitor bortezomib can overcome lapatinib resistance. Treatments with several proteasome inhibitors, including Bortezomib, MG132, and proteasome inhibitor I (PSI), as well as the viabilities of both HER2-positive breast cancer cell lines and their lapatinib-resistant clones, were inhibited. Importantly, the expressions of ErbB family were downregulated at both transcriptional and translational levels. Also, our results further indicated that proteasome inhibitors decreased ErbB family expression through lysosomal degradation pathway in a heat shock protein 90 (HSP90)-dependent manner. In this study, our data supported a potential approach to overcome the acquired resistance of HER2-overexpressing breast cancer patients to lapatinib using proteasome inhibitors.
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Affiliation(s)
- Thanh Kieu Huynh
- Graduate Institute of Biomedical Science, China Medical University, Taichung 404, Taiwan.
| | - Chien-Yi Ho
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung 404, Taiwan.
- Department of Family Medicine, China Medical University Hsinchu Hospital, Hsinchu 302, Taiwan.
- Physical Examination Center, China Medical University Hsinchu Hospital, Hsinchu 302, Taiwan.
- Department of Medical Research, China Medical University Hsinchu Hospital, Hsinchu 302, Taiwan.
| | - Chi-Hua Tsai
- Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan.
| | - Chien-Kuo Wang
- Department of Biotechnology, Asia University, Taichung 413, Taiwan.
| | - Yun-Ju Chen
- Department of Medical Research, E-Da Hospital, Kaohsiung 824, Taiwan.
- School of Medicine for International Students, I-Shou University, Kaohsiung 824, Taiwan.
- Department of Pharmacy, E-Da Hospital, Kaohsiung 824, Taiwan.
| | - Da-Tian Bau
- Graduate Institute of Biomedical Science, China Medical University, Taichung 404, Taiwan.
- Terry Fox Cancer Research Laboratory, Translational Medicine Research Center, China Medical University Hospital, Taichung 404, Taiwan.
| | - Chih-Yen Tu
- School of Medicine, College of Medicine, China Medical University, Taichung 404, Taiwan.
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung 404, Taiwan.
| | - Tzong-Shiun Li
- Department of Plastic Surgery, Show Chwan Memorial Hospital, Changhua 500, Taiwan.
- Innovation Research Center, Show Chwan Health Care System, Changhua 500, Taiwan.
| | - Wei-Chien Huang
- Graduate Institute of Biomedical Science, China Medical University, Taichung 404, Taiwan.
- Graduate Institute of Cancer Biology, China Medical University, Taichung 404, Taiwan.
- Department of Biotechnology, Asia University, Taichung 413, Taiwan.
- The Ph.D. Program for Cancer Biology and Drug Discovery, China Medical University, Taichung 404, Taiwan.
- Center for Molecular Medicine, China Medical University Hospital, Taichung 404, Taiwan.
- Drug Development Center, China Medical University, Taichung 404, Taiwan.
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7
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Parkin facilitates proteasome inhibitor-induced apoptosis via suppression of NF-κB activity in hepatocellular carcinoma. Cell Death Dis 2019; 10:719. [PMID: 31558697 PMCID: PMC6763437 DOI: 10.1038/s41419-019-1881-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 07/17/2019] [Accepted: 07/30/2019] [Indexed: 12/30/2022]
Abstract
The ubiquitin–proteasome system (UPS) is a tight homeostatic control mechanism of intracellular protein degradation and turnover involved in many human diseases. Proteasome inhibitors were initially developed as anticancer agents with potential benefits in the suppression of tumor growth. However, clinical trials of patients with solid tumors fail to demonstrate the same efficacy of these proteasome inhibitors. Here, we show that Parkin, an E3 ubiquitin ligase, is implicated in tumorigenesis and therapy resistance of hepatocellular carcinoma (HCC), the most common type of primary liver cancer in adults. Lower Parkin expression correlates with poor survival in patients with HCC. Ectopic Parkin expression enhances proteasome inhibitor-induced apoptosis and tumor suppression in HCC cells in vitro and in vivo. In contrast, knockdown of Parkin expression promotes apoptosis resistance and tumor growth. Mechanistically, Parkin promotes TNF receptor-associated factor (TRAF) 2 and TRAF6 degradation and thus facilitates nuclear factor-kappa-B (NF-κB) inhibition, which finally results in apoptosis. These findings reveal a direct molecular link between Parkin and protein degradation in the control of the NF-κB pathway and may provide a novel UPS-dependent strategy for the treatment of HCC by induction of apoptosis.
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8
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Moghbeli M. Genetic and molecular biology of breast cancer among Iranian patients. J Transl Med 2019; 17:218. [PMID: 31286981 PMCID: PMC6615213 DOI: 10.1186/s12967-019-1968-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/04/2019] [Indexed: 02/07/2023] Open
Abstract
Abstract Background, Breast cancer (BC) is one of the leading causes of cancer related deaths in Iran. This high ratio of mortality had a rising trend during the recent years which is probably associated with late diagnosis. Main body Therefore it is critical to define a unique panel of genetic markers for the early detection among our population. In present review we summarized all of the reported significant genetic markers among Iranian BC patients for the first time, which are categorized based on their cellular functions. Conclusions This review paves the way of introducing a unique ethnic specific panel of diagnostic markers among Iranian BC patients. Indeed, this review can also clarify the genetic and molecular bases of BC progression among Iranians.
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Affiliation(s)
- Meysam Moghbeli
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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9
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Luhtala S, Staff S, Kallioniemi A, Tanner M, Isola J. Clinicopathological and prognostic correlations of HER3 expression and its degradation regulators, NEDD4-1 and NRDP1, in primary breast cancer. BMC Cancer 2018; 18:1045. [PMID: 30367623 PMCID: PMC6204010 DOI: 10.1186/s12885-018-4917-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/08/2018] [Indexed: 12/17/2022] Open
Abstract
Background Human epidermal growth factor receptor HER3 (ErbB3), especially in association with its relative HER2 (ErbB2), is known as a key oncogene in breast tumour biology. Nonetheless, the prognostic relevance of HER3 remains controversial. NEDD4–1 and NRDP1 are signalling molecules closely related to the degradation of HER3 via ubiquitination. NEDD4–1 and NRDP1 have been reported to contribute to HER3-mediated signalling by regulating its localization and cell membrane retention. We studied correlations between HER3, NEDD4–1, and NRDP1 protein expression and their association with tumour histopathological characteristics and clinical outcomes. Methods The prevalence of immunohistochemically detectable expression profiles of HER3 (n = 177), NEDD4–1 (n = 145), and NRDP1 (n = 145) proteins was studied in primary breast carcinomas on archival formalin-fixed paraffin-embedded (FFPE) samples. Clinicopathological correlations were determined statistically using Pearson’s Chi-Square test. The Kaplan-Meier method, log-rank test (Mantel-Cox), and Cox regression analysis were utilized for survival analysis. Results HER3 protein was expressed in breast carcinomas without association with HER2 gene amplification status. Absence or low HER3 expression correlated with clinically aggressive features, such as triple-negative breast cancer (TNBC) phenotype, basal cell origin (cytokeratin 5/14 expression combined with ER negativity), large tumour size, and positive lymph node status. Low total HER3 expression was prognostic for shorter recurrence-free survival time in HER2-amplified breast cancer (p = 0.004, p = 0.020 in univariate and multivariate analyses, respectively). The majority (82.8%) of breast cancers demonstrated NEDD4–1 protein expression - while only a minor proportion (8.3%) of carcinomas expressed NRDP1. NEDD4–1 and NRDP1 expression were not associated with clinical outcomes in HER2-amplified breast cancer, irrespective of adjuvant trastuzumab therapy. Conclusions Low HER3 expression is suggested to be a valuable prognostic biomarker to predict recurrence in HER2-amplified breast cancer. Neither NEDD4–1 nor NRDP1 demonstrated relevance in prognostics or in the subclassification of HER2-amplified breast carcinomas. Electronic supplementary material The online version of this article (10.1186/s12885-018-4917-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Satu Luhtala
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Arvo Ylpön katu 34, 33520, Tampere, Finland.
| | - Synnöve Staff
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Arvo Ylpön katu 34, 33520, Tampere, Finland.,Department of Obstetrics and Gynecology, Tampere University Hospital, Tampere, Finland
| | - Anne Kallioniemi
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Arvo Ylpön katu 34, 33520, Tampere, Finland
| | - Minna Tanner
- Department of Oncology, Tampere University Hospital, Tampere, Finland
| | - Jorma Isola
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Arvo Ylpön katu 34, 33520, Tampere, Finland
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10
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Ho SR, Lin WC. RNF144A sustains EGFR signaling to promote EGF-dependent cell proliferation. J Biol Chem 2018; 293:16307-16323. [PMID: 30171075 DOI: 10.1074/jbc.ra118.002887] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 08/01/2018] [Indexed: 11/06/2022] Open
Abstract
RNF144A is a single-pass transmembrane RBR E3 ligase that interacts with and degrades cytoplasmic DNA-PKcs, which is an epidermal growth factor receptor (EGFR)-interacting partner. Interestingly, RNF144A expression is positively correlated with EGFR mRNA and protein levels in several types of cancer. However, the relationship between RNF144A and EGFR is poorly understood. This study reports an unexpected role for RNF144A in the regulation of EGF/EGFR signaling and EGF-dependent cell proliferation. EGFR ligands, but not DNA-damaging agents, induce a DNA-PKcs-independent interaction between RNF144A and EGFR. RNF144A promotes EGFR ubiquitination, maintains EGFR protein, and prolongs EGF/EGFR signaling during EGF stimulation. Moreover, depletion of RNF144A by multiple independent approaches results in a decrease in EGFR expression and EGF/EGFR signaling. RNF144A knockout cells also fail to mount an immediate response to EGF for activation of G1/S progression genes. Consequently, depletion of RNF144A reduces EGF-dependent cell proliferation. These defects may be at least in part due to a role for RNF144A in regulating EGFR transport in the intracellular vesicles during EGF treatment.
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Affiliation(s)
- Shiuh-Rong Ho
- From the Section of Hematology/Oncology, Department of Medicine
| | - Weei-Chin Lin
- From the Section of Hematology/Oncology, Department of Medicine, .,the Department of Molecular and Cellular Biology, and.,the Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030
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11
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Ghezzi C, Calmettes G, Morand P, Ribalet B, John S. Real-time imaging of sodium glucose transporter (SGLT1) trafficking and activity in single cells. Physiol Rep 2018; 5:5/3/e13062. [PMID: 28193781 PMCID: PMC5309568 DOI: 10.14814/phy2.13062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/07/2016] [Indexed: 01/12/2023] Open
Abstract
The processes controlling targeting of glucose transporters to apical and basolateral membranes of polarized cells are complex and not-well understood. We have engineered SGLT1 and GLUT4 constructs linked to fluorescent proteins to highlight the differences in transporter expression and trafficking, in real time, in different cell types. Activity was assessed in parallel using a FRET glucose sensor. In COS cells and HEK cells, SGLT1 was distributed between the plasma membrane and intracellular compartments, but there was little expression in CHO cells. Trafficking was investigated using the lysosome inhibitors NH4Cl (10 mmol/L) and chloroquine (150 μmol/L) and the proteasome inhibitors MG-262 (1 μmol/L) and lactacystin (5 μmol/L). Lysosome inhibitors caused SGLT1 accumulation into intracellular bodies, whereas proteasome inhibitors induced SGLT1 accumulation in the plasma membrane, even in CHO cells. Our data suggest that a fraction of SGLT1 is rapidly degraded by lysosomes and never reached the plasma membrane; another fraction reaches the membrane and is subsequently degraded by lysosomes following internalization. The latter process is regulated by the ubiquitin/proteasome pathway, acting at a late stage of the lysosomal pathway. Using the cholesterol inhibitor MβCD (3 mmol/L), a dominant negative dynamin (K44A) and caveolin, we showed that SGLT1 internalization is lipid raft-mediated, but caveolin-independent. In contrast, GLUT4 internalization is dynamin-dependent, but cholesterol-independent. The physiological relevance of these data is discussed in terms of differential membrane compartmentalization of the transporters and expression under stress conditions.
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Affiliation(s)
- Chiara Ghezzi
- Departments of Physiology and Medicine and the Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Guillaume Calmettes
- Departments of Physiology and Medicine and the Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Pauline Morand
- Departments of Physiology and Medicine and the Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Bernard Ribalet
- Departments of Physiology and Medicine and the Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Scott John
- Departments of Physiology and Medicine and the Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, California
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12
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Wang W, Qu M, Wang J, Zhang X, Zhang H, Wu J, Yu B, Wu H, Kong W, Yu X. Autoubiquitination of feline E3 ubiquitin ligase BCA2. Gene 2018; 638:1-6. [DOI: 10.1016/j.gene.2017.09.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/13/2017] [Accepted: 09/26/2017] [Indexed: 12/21/2022]
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13
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Hou J, Deng Q, Zhou J, Zou J, Zhang Y, Tan P, Zhang W, Cui H. CSN6 controls the proliferation and metastasis of glioblastoma by CHIP-mediated degradation of EGFR. Oncogene 2016; 36:1134-1144. [PMID: 27546621 DOI: 10.1038/onc.2016.280] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 06/04/2016] [Accepted: 06/27/2016] [Indexed: 12/31/2022]
Abstract
CSN6, a critical subunit of the constitutive photomorphogenesis 9 (COP9) signalosome (CSN), has received attention as a regulator of the degradation of cancer-related proteins such as p53, c-myc and c-Jun, through the ubiquitin-proteasome system, suggesting its importance in cancerogenesis. However, the biological functions and molecular mechanisms of CSN6 in glioblastoma (GBM) remain poorly understood. Here, we report that GBM tumors overexpressed CSN6 compared with normal brain tissues and that CSN6 promoted GBM cell proliferation, migration, invasion and tumorigenesis. Erlotinib, a small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, was used to reveal that the proliferative and metastatic effects of CSN6 on GBM cells were EGFR dependent. We also found that CSN6 positively regulated EGFR stability via reduced levels of EGFR ubiquitination, thereby elevating steady expression of EGFR. In addition, this study is the first description of a novel role for the CSN6-interacting E3 ligase, CHIP (carboxyl terminus of heat-shock protein 70-interacting protein), regulating EGFR ubiquitination in cancer cells. We showed that CSN6 associated with CHIP and led to CHIP destabilization by increasing CHIP self-ubiquitination. Moreover, CSN6 decreased CHIP expression and increased EGFR expression in the tumor samples. Deregulation of this axis promoted GBM cell's proliferation and metastasis. Thus, our study provides insights into the applicability of using the CSN6-CHIP-EGFR axis as a potential therapeutic target in cancer.
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Affiliation(s)
- J Hou
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Q Deng
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - J Zhou
- Department of Neurosurgery, Rocket Force General Hospital, Chinese People's Liberation Army, Beijing, China
| | - J Zou
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Y Zhang
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - P Tan
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - W Zhang
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - H Cui
- Cell Biology Laboratory, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
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Le Clorennec C, Lazrek Y, Dubreuil O, Larbouret C, Poul MA, Mondon P, Melino G, Pèlegrin A, Chardès T. The anti-HER3 (ErbB3) therapeutic antibody 9F7-F11 induces HER3 ubiquitination and degradation in tumors through JNK1/2- dependent ITCH/AIP4 activation. Oncotarget 2016; 7:37013-37029. [PMID: 27203743 PMCID: PMC5095055 DOI: 10.18632/oncotarget.9455] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/16/2016] [Indexed: 01/28/2023] Open
Abstract
We characterized the mechanism of action of the neuregulin-non-competitive anti-HER3 therapeutic antibody 9F7-F11 that blocks the PI3K/AKT pathway, leading to cell cycle arrest and apoptosis in vitro and regression of pancreatic and breast cancer in vivo. We found that 9F7-F11 induces rapid HER3 down-regulation. Specifically, 9F7-F11-induced HER3 ubiquitination and degradation in pancreatic, breast and prostate cancer cell lines was driven mainly by the itchy E3 ubiquitin ligase (ITCH/AIP4). Overexpression of the ITCH/AIP4 inhibitor N4BP1 or small-interfering RNA-mediated knockdown of ITCH/AIP4 inhibited HER3 ubiquitination/degradation and PI3K/AKT signaling blockade induced by 9F7-F11. Moreover, 9F7-F11-mediated JNK1/2 phosphorylation led to ITCH/AIP4 activation and recruitment to HER3 for receptor ubiquitination and degradation. ITCH/AIP4 activity was activated by the deubiquitinases USP8 and USP9X, as demonstrated by RNA interference. Taken together, our results suggest that 9F7-F11-induced HER3 ubiquitination and degradation in cancer cells mainly occurs through JNK1/2-dependent ITCH/AIP4 activation.
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Affiliation(s)
- Christophe Le Clorennec
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France
- INSERM, U1194 Montpellier, Montpellier, F-34298, France
- Université de Montpellier, Montpellier, F-34298, France
- ICM, Institut Régional du Cancer Montpellier, Montpellier, F-34298, France
| | - Yassamine Lazrek
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France
- INSERM, U1194 Montpellier, Montpellier, F-34298, France
- Université de Montpellier, Montpellier, F-34298, France
- ICM, Institut Régional du Cancer Montpellier, Montpellier, F-34298, France
- Millegen SA, Labège, F-31670, France
- Institut Pasteur de Guyane, BP 6010, 97306, Cayenne Cedex, France
| | - Olivier Dubreuil
- Millegen SA, Labège, F-31670, France
- GamaMabs Pharma SA, Centre Pierre Potier, ONCOPOLE, BP 50624, France
| | - Christel Larbouret
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France
- INSERM, U1194 Montpellier, Montpellier, F-34298, France
- Université de Montpellier, Montpellier, F-34298, France
- ICM, Institut Régional du Cancer Montpellier, Montpellier, F-34298, France
| | - Marie-Alix Poul
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France
- INSERM, U1194 Montpellier, Montpellier, F-34298, France
- Université de Montpellier, Montpellier, F-34298, France
- ICM, Institut Régional du Cancer Montpellier, Montpellier, F-34298, France
| | - Philippe Mondon
- Millegen SA, Labège, F-31670, France
- LFB Biotechnologies, 59000, Lille, France
| | - Gerry Melino
- Biochemistry Laboratory, Instituto Dermopatico Dell'Immacolata, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata,” 00133 Rome, Italy
- Toxicology Unit, Medical Research Council, Leicester University, Leicester LE1 9HN, United Kingdom
| | - André Pèlegrin
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France
- INSERM, U1194 Montpellier, Montpellier, F-34298, France
- Université de Montpellier, Montpellier, F-34298, France
- ICM, Institut Régional du Cancer Montpellier, Montpellier, F-34298, France
| | - Thierry Chardès
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France
- INSERM, U1194 Montpellier, Montpellier, F-34298, France
- Université de Montpellier, Montpellier, F-34298, France
- ICM, Institut Régional du Cancer Montpellier, Montpellier, F-34298, France
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Tu DG, Yu Y, Lee CH, Kuo YL, Lu YC, Tu CW, Chang WW. Hinokitiol inhibits vasculogenic mimicry activity of breast cancer stem/progenitor cells through proteasome-mediated degradation of epidermal growth factor receptor. Oncol Lett 2016; 11:2934-2940. [PMID: 27073579 DOI: 10.3892/ol.2016.4300] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 02/11/2016] [Indexed: 01/16/2023] Open
Abstract
Hinokitiol, alternatively known as β-thujaplicin, is a tropolone-associated natural compound with antimicrobial, anti-inflammatory and antitumor activity. Breast cancer stem/progenitor cells (BCSCs) are a subpopulation of breast cancer cells associated with tumor initiation, chemoresistance and metastatic behavior, and may be enriched by mammosphere cultivation. Previous studies have demonstrated that BCSCs exhibit vasculogenic mimicry (VM) activity via the epidermal growth factor receptor (EGFR) signaling pathway. The present study investigated the anti-VM activity of hinokitiol in BCSCs. At a concentration below the half maximal inhibitory concentration, hinokitiol inhibited VM formation of mammosphere cells derived from two human breast cancer cell lines. Hinokitiol was additionally indicated to downregulate EGFR protein expression in mammosphere-forming BCSCs without affecting the expression of messenger RNA. The protein stability of EGFR in BCSCs was also decreased by hinokitiol. The EGFR protein expression and VM formation capability of hinokitiol-treated BCSCs were restored by co-treatment with MG132, a proteasome inhibitor. In conclusion, the present study indicated that hinokitiol may inhibit the VM activity of BCSCs through stimulating proteasome-mediated EGFR degradation. Hinokitiol may act as an anti-VM agent, and may be useful for the development of novel breast cancer therapeutic agents.
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Affiliation(s)
- Dom-Gene Tu
- Department of Nuclear Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan, R.O.C.; Department of Food Science and Technology, Chia Nan University of Pharmacy & Science, Tainan 717, Taiwan, R.O.C.; Graduate Institute of Medical Sciences, College of Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan, R.O.C
| | - Yun Yu
- School of Biomedical Sciences, College of Medical Science and Technology, Chung Shan Medical University, Taichung 40201, Taiwan, R.O.C
| | - Che-Hsin Lee
- Graduate Institute of Basic Medical Science, School of Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C.; Department of Microbiology, School of Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Yu-Liang Kuo
- Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung 40201, Taiwan, R.O.C.; School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung 40201, Taiwan, R.O.C
| | - Yin-Che Lu
- Division of Hematology-Oncology, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan, R.O.C
| | - Chi-Wen Tu
- Department of Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi 60002, Taiwan, R.O.C
| | - Wen-Wei Chang
- School of Biomedical Sciences, College of Medical Science and Technology, Chung Shan Medical University, Taichung 40201, Taiwan, R.O.C.; Department of Medical Research, Chung Shan Medical University Hospital, Taichung 40201, Taiwan, R.O.C
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Chaiyadet S, Smout M, Johnson M, Whitchurch C, Turnbull L, Kaewkes S, Sotillo J, Loukas A, Sripa B. Excretory/secretory products of the carcinogenic liver fluke are endocytosed by human cholangiocytes and drive cell proliferation and IL6 production. Int J Parasitol 2015; 45:773-81. [PMID: 26187786 DOI: 10.1016/j.ijpara.2015.06.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/18/2015] [Accepted: 06/06/2015] [Indexed: 01/22/2023]
Abstract
Liver fluke infection caused by Opisthorchis viverrini remains a major public health problem in many parts of Asia including Thailand, Lao PDR, Vietnam and Cambodia, where there is a strikingly high incidence of cholangiocarcinoma (CCA - hepatic cancer of the bile duct epithelium). Among other factors, uptake of O. viverrini excretory/secretory products (OvES) by biliary epithelial cells has been postulated to be responsible for chronic inflammation and proliferation of cholangiocytes, but the mechanisms by which cells internalise O. viverrini excretory/secretory products are still unknown. Herein we incubated normal human cholangiocytes (H69), human cholangiocarcinoma cells (KKU-100, KKU-M156) and human colon cancer (Caco-2) cells with O. viverrini excretory/secretory products and analysed the effects of different endocytic inhibitors to address the mechanism of cellular uptake of ES proteins. Opisthorchis viverrini excretory/secretory products was internalised preferentially by liver cell lines, and most efficiently/rapidly by H69 cells. There was no evidence for trafficking of ES proteins to cholangiocyte organelles, and most of the fluorescence was detected in the cytoplasm. Pretreatment with clathrin inhibitors significantly reduced the uptake of O. viverrini excretory/secretory products, particularly by H69 cells. Opisthorchis viverrini excretory/secretory products induced proliferation of liver cells (H69 and CCA lines) but not intestinal (Caco-2) cells, and proliferation was blocked using inhibitors of the classical endocytic pathways (clathrin and caveolae). Opisthorchis viverrini excretory/secretory products drove IL6 secretion by H69 cells but not Caco-2 cells, and cytokine secretion was significantly reduced by endocytosis inhibitors. This the first known study to address the endocytosis of helminth ES proteins by host epithelial cells and sheds light on the pathways by which this parasite causes one of the most devastating forms of cancer in south-eastern Asia.
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Affiliation(s)
- Sujittra Chaiyadet
- Biomedical Sciences Program, Graduate School, Khon Kaen University, Khon Kaen, Thailand; Tropical Disease Research Laboratory, Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Michael Smout
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Michael Johnson
- Faculty of Science, University of Technology Sydney, Sydney, Australia
| | | | - Lynne Turnbull
- Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Sasithorn Kaewkes
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Javier Sotillo
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Banchob Sripa
- Tropical Disease Research Laboratory, Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
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Ellina MI, Bouris P, Kletsas D, Aletras A, Karamanos N. Epidermal growth factor/epidermal growth factor receptor signaling axis is a significant regulator of the proteasome expression and activity in colon cancer cells. SCIENCEOPEN RESEARCH 2014. [DOI: 10.14293/s2199-1006.1.sor-life.aac0e6.v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Colon cancer is the third most common type of cancer worldwide. Epidermal growth factor receptor (EGFR) plays a crucial role in the (patho)physiology of the disease. EGFR controls vital cellular processes, while this action is associated with poor prognosis. In addition, K-Ras mutations are associated with the promotion of the disease and the anti-EGFR resistance. The ubiquitin-proteasome system plays also a very important role in cancer, modulating cell cycle and other cellular processes such as the growth and the survival of cancer cells. Proteasome inhibition affects, in several cases, the action and the protein levels of EGFR. Nevertheless, little is known whether the reversed option is possible. In this study, we, therefore, investigated the impact of epidermal growth factor (EGF)/EGFR signaling axis on gene expression and the proteolytic activity of the proteasome subunits, as well as whether Nrf2, an activator of proteasome expression, plays a role in this process. Moreover, we evaluated whether EGF regulates the expression of its own receptor and the proliferation rate of DLD-1 (K-Ras mutated) colon cancer cells. The obtained data showed that, although EGF has no significant effect on the proliferation of DLD-1 colon cancer cells, it significantly upregulates the expression of EGFR as well as the expression and the activity of the proteasome, suggesting that the EGF-mediated proteasome activation could possibly lead to enhanced EGFR degradation leading to autoregulation of EGF–EGFR pathway. Nrf2 activation did not induce proteasome gene expression in DLD-1 colon cancer cells.
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EGF/EGFR signaling axis is a significant regulator of the proteasome expression and activity in colon cancer cells. SCIENCEOPEN RESEARCH 2014. [DOI: 10.14293/a2199-1006.01.sor-life.ac0e6.v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Colon cancer is the third most common type of cancer worldwide. Epidermal growth factor receptor (EGFR) plays a crucial role in the (patho)physiology of the disease. EGFR controls vital cellular processes, while this action is associated with poor prognosis. In addition, K-Ras mutations are associated with the promotion of the disease and the anti-EGFR resistance. The ubiquitin-proteasome system plays also a very important role in cancer, modulating cell cycle and other cellular processes such as the growth and the survival of cancer cells. Proteasome inhibition affects, in several cases, the action and the protein levels of EGFR. Nevertheless, little is known whether the reversed option is possible. In this study, we, therefore, investigated the impact of epidermal growth factor (EGF)/EGFR signaling axis on gene expression and the proteolytic activity of the proteasome subunits, as well as whether Nrf2, an activator of proteasome expression, plays a role in this process. Moreover, we evaluated whether EGF regulates the expression of its own receptor and the proliferation rate of DLD-1 (K-Ras mutated) colon cancer cells. The obtained data showed that, although EGF has no significant effect on the proliferation of DLD-1 colon cancer cells, it significantly upregulates the expression of EGFR as well as the expression and the activity of the proteasome, suggesting that the EGF-mediated proteasome activation could possibly lead to enhanced EGFR degradation leading to autoregulation of EGF–EGFR pathway. Nrf2 activation did not induce proteasome gene expression in DLD-1 colon cancer cells.
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19
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The E3 ubiquitin ligase NEDD4 negatively regulates HER3/ErbB3 level and signaling. Oncogene 2014; 34:1105-15. [PMID: 24662824 DOI: 10.1038/onc.2014.56] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 01/06/2014] [Accepted: 01/12/2014] [Indexed: 01/07/2023]
Abstract
HER3/ErbB3, a member of the epidermal growth factor receptor (EGFR) family, has a pivotal role in cancer and is emerging as a therapeutic antibody target. In this study, we identified NEDD4 (neural precursor cell expressed, developmentally downregulated 4) as a novel interaction partner and ubiquitin E3 ligase of human HER3. Using molecular and biochemical approaches, we demonstrated that the C-terminal tail of HER3 interacted with the WW domains of NEDD4 and the interaction was independent of neuregulin-1. Short hairpin RNA knockdown of NEDD4 elevated HER3 levels and resulted in increased HER3 signaling and cancer cell proliferation in vitro and in vivo. A similar inverse relationship between HER3 and NEDD4 levels was observed in prostate cancer tumor tissues. More importantly, the upregulated HER3 expression by NEDD4 knockdown sensitized cancer cells for growth inhibition by an anti-HER3 antibody. Taken together, our results suggest that low NEDD4 levels may predict activation of HER3 signaling and efficacies of anti-HER3 antibody therapies.
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Tushar MD, Ramanathan A. Tyrosine 1045 codon mutations in exon 27 of EGFR are infrequent in oral squamous cell carcinomas. Asian Pac J Cancer Prev 2014; 14:4279-82. [PMID: 23991943 DOI: 10.7314/apjcp.2013.14.7.4279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The activation and inactivation of receptor tyrosine kinases are tightly regulated to ensure faithful replication of cells. After having transduced extracellular growth activating signals, activated EGFR is subjected to downregulation either by clathrin mediated endocytosis or c-Cbl mediated proteasome degradation depending on the ligand concentration. c-Cbl is an ubiquitin ligase which requires a phosphorylated tyrosine residue at position 1045 in the cytoplasmic domain of EGFR to interact and add ubiquitin molecules. While activating mutations in exons 19 and 21 have been associated with the development of several cancers, the status of mutations at tyrosine 1045 coding exon 27 of EGFR remain to be investigated. Consistently, defective phosphorylation at 1045 has been associated with sustained phosphorylation of EGFR in non-small lung carcinomas. Hence in the present study we investigated the genetic status of the tyrosine 1045 coding site within exon 27 of EGFR gene to explore for possible occurrence of mutations in this region, especially since no studies have addressed this issue so far. MATERIALS AND METHODS Tumor chromosomal DNA isolated from thirty five surgically excised oral squamous cell carcinoma tissues was subjected to PCR amplification with intronic primers flanking the tyrosine 1045 coding exon 27 of EGFR gene. The PCR amplicons were subsequently subjected to direct sequencing to elucidate the mutation status. RESULTS Sequence analysis identified no mutations in the tyrosine 1045 codon of EGFR in any of the thirty five samples that were analyzed. CONCLUSIONS The lack of identification of mutation in the tyrosine 1045 codon of EGFR suggests that mutations in this region may be relatively rare in oral squamous cell carcinomas. To the best of our knowledge, this study is the first to have explored the genetic status of exon 27 of EGFR in oral squamous cell carcinoma tissue samples.
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Affiliation(s)
- Mehta Dhaval Tushar
- Human Genetics Laboratory, Sree Balaji Medical and Dental College and Hospital, Bharath University, Chennai, India.
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21
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Narváez-Pita X, Ortega-Zuniga C, Acevedo-Morantes CY, Pastrana B, Olivero-Verbel J, Maldonado-Rojas W, Ramírez-Vick JE, Meléndez E. Water soluble molybdenocene complexes: Synthesis, cytotoxic activity and binding studies to ubiquitin by fluorescence spectroscopy, circular dichroism and molecular modeling. J Inorg Biochem 2014; 132:77-91. [DOI: 10.1016/j.jinorgbio.2013.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/17/2013] [Accepted: 10/19/2013] [Indexed: 11/24/2022]
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Wang F, Wang L, Xu Z, Liang G. Identification and analysis of multi-protein complexes in placenta. PLoS One 2013; 8:e62988. [PMID: 23638173 PMCID: PMC3639281 DOI: 10.1371/journal.pone.0062988] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 03/27/2013] [Indexed: 12/13/2022] Open
Abstract
Placental malfunction induces pregnancy disorders which contribute to life-threatening complications for both the mother and the fetus. Identification and characterization of placental multi-protein complexes is an important step to integratedly understand the protein-protein interaction networks in placenta which determine placental function. In this study, blue native/sodium dodecyl sulfate polyacrylamide gel electrophoresis (BN/SDS-PAGE) and Liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to screen the multi-protein complexes in placenta. 733 unique proteins and 34 known and novel heterooligomeric multi-protein complexes including mitochondrial respiratory chain complexes, integrin complexes, proteasome complexes, histone complex, and heat shock protein complexes were identified. A novel protein complex, which involves clathrin and small conductance calcium-activated potassium (SK) channel protein 2, was identified and validated by antibody based gel shift assay, co-immunoprecipitation and immunofluorescence staining. These results suggest that BN/SDS-PAGE, when integrated with LC-MS/MS, is a very powerful and versatile tool for the investigation of placental protein complexes. This work paves the way for deeper functional characterization of the placental protein complexes associated with pregnancy disorders.
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Affiliation(s)
- Fuqiang Wang
- CAS Key Laboratory of Soft Matter Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, China
- State Key Laboratory of Reproductive Medicine, Analysis Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ling Wang
- State Key Laboratory of Reproductive Medicine, Analysis Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zhiyang Xu
- State Key Laboratory of Reproductive Medicine, Analysis Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Gaolin Liang
- CAS Key Laboratory of Soft Matter Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, China
- * E-mail:
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Sévère N, Dieudonné FX, Marie PJ. E3 ubiquitin ligase-mediated regulation of bone formation and tumorigenesis. Cell Death Dis 2013; 4:e463. [PMID: 23328670 PMCID: PMC3564004 DOI: 10.1038/cddis.2012.217] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The ubiquitination–proteasome and degradation system is an essential process that regulates protein homeostasis. This system is involved in the regulation of cell proliferation, differentiation and survival, and dysregulations in this system lead to pathologies including cancers. The ubiquitination system is an enzymatic cascade that mediates the marking of target proteins by an ubiquitin label and thereby directs their degradation through the proteasome pathway. The ubiquitination of proteins occurs through a three-step process involving ubiquitin activation by the E1 enzyme, allowing for the transfer to a ubiquitin-conjugated enzyme E2 and to the targeted protein via ubiquitin-protein ligases (E3), the most abundant group of enzymes involved in ubiquitination. Significant advances have been made in our understanding of the role of E3 ubiquitin ligases in the control of bone turnover and tumorigenesis. These ligases are implicated in the regulation of bone cells through the degradation of receptor tyrosine kinases, signaling molecules and transcription factors. Initial studies showed that the E3 ubiquitin ligase c-Cbl, a multi-domain scaffold protein, regulates bone resorption by interacting with several molecules in osteoclasts. Further studies showed that c-Cbl controls the ubiquitination of signaling molecules in osteoblasts and in turn regulates osteoblast proliferation, differentiation and survival. Recent data indicate that c-Cbl expression is decreased in primary bone tumors, resulting in excessive receptor tyrosine kinase signaling. Consistently, c-Cbl ectopic expression reduces bone tumorigenesis by promoting tyrosine kinase receptor degradation. Here, we review the mechanisms of action of E3 ubiquitin ligases in the regulation of normal and pathologic bone formation, and we discuss how targeting the interactions of c-Cbl with some substrates may be a potential therapeutic strategy to promote osteogenesis and to reduce tumorigenesis.
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Affiliation(s)
- N Sévère
- Laboratory of Osteoblast Biology and Pathology, INSERM U606, Paris, France
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Fu-Jun L, Shao-Hua J, Xiao-Fang S. Differential proteomic analysis of pathway biomarkers in human breast cancer by integrated bioinformatics. Oncol Lett 2012; 4:1097-1103. [PMID: 23162659 DOI: 10.3892/ol.2012.881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/24/2012] [Indexed: 12/25/2022] Open
Abstract
The aim of this study was to better understand the altered functional modules in breast cancer at pathway and network levels. An integrated bioinformatics analysis of differentially expressed proteins in human breast cancer was performed. Breast cancer protein profiles were constructed by data mining proteins in literature and public databases, including 1031 proteins with 153 secretory and 69 cell surface proteins. An experimental investigation was performed by two-dimensional electrophoresis, and 4 proteins were further validated by western blotting. Enriched bioinformatics functions were clustered. This study may be used as a reference in further studies to help identify the underlying biological interactions associated with breast cancer and discover potential cancer targets.
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Seghatoleslam A, Nikseresht M, Shafiee SM, Monabati A, Namavari MM, Talei A, Safaei A, Owji AA. Expression of the novel human gene, UBE2Q1, in breast tumors. Mol Biol Rep 2011; 39:5135-41. [PMID: 22167327 DOI: 10.1007/s11033-011-1309-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 11/30/2011] [Indexed: 12/21/2022]
Abstract
The novel human gene, designated ubiquitin-conjugating enzyme E2Q family member 1 (UBE2Q1) maps to chromosome 1q21.3. The gene has an open reading frame corresponding to 422 amino acids and contains a RWD domain and an E2 ubiquitin conjugating enzyme domain. Here, we investigated the expression levels of both mRNA and protein of UBE2Q1 gene in cancerous versus normal parts of breast specimens from 26 patients. Real-time PCR data showed that the relative expression level of UBE2Q1 mRNA was significantly greater in cancers than in non-cancerous tissues of breast specimens (Mean ± SEM, 0.064 ± 0.015 for cancers and 0.026 ± 0.01 for noncancerous tissues, P < 0.05 Mann-Whitney test). A rabbit polyclonal antibody was generated against an amino acid sequence predicted from the DNA sequence of UBE2Q1 gene. This antibody was used to perform Western blotting on 21 cases in our cohort of breast specimens. Thus, 13 (61.904%) of the cases showed an increase in the UBE2Q1 immunoreactivity in their cancerous tissues as compared with the corresponding normal tissues. This result along with the real-time PCR data shows that the novel human gene, UBE2Q1, is expressed in human breast and may have implications for pathogenesis of breast cancer.
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Affiliation(s)
- Atefeh Seghatoleslam
- Department of Biochemistry, Shiraz University of Medical Sciences, P.O. Box 1167, Shiraz, Iran
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Cheng SB, Quinn JA, Graeber CT, Filardo EJ. Down-modulation of the G-protein-coupled estrogen receptor, GPER, from the cell surface occurs via a trans-Golgi-proteasome pathway. J Biol Chem 2011; 286:22441-55. [PMID: 21540189 PMCID: PMC3121390 DOI: 10.1074/jbc.m111.224071] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 04/26/2011] [Indexed: 11/06/2022] Open
Abstract
GPER is a G(s)-coupled seven-transmembrane receptor that has been linked to specific estrogen binding and signaling activities that are manifested by plasma membrane-associated enzymes. However, in many cell types, GPER is predominately localized to the endoplasmic reticulum (ER), and only minor amounts of receptor are detectable at the cell surface, an observation that has caused controversy regarding its role as a plasma membrane estrogen receptor. Here, we show that GPER constitutively buds intracellularly into EEA-1+ endosomes from clathrin-coated pits. Nonvisual arrestins-2/-3 do not co-localize with GPER, and expression of arrestin-2 dominant-negative mutants lacking clathrin- or β-adaptin interaction sites fails to block GPER internalization suggesting that arrestins are not involved in GPER endocytosis. Like β1AR, which recycles to the plasma membrane, GPER co-traffics with transferrin+, Rab11+ recycling endosomes. However, endocytosed GPER does not recycle to the cell surface, but instead returns to the trans-Golgi network (TGN) and does not re-enter the ER. GPER is ubiquitinated at the cell surface, exhibits a short half-life (t½;) <1 h), and is protected from degradation by the proteasome inhibitor, MG132. Disruption of the TGN by brefeldin A induces the accumulation of endocytosed GPER in Rab11+ perinuclear endosomes and prevents GPER degradation. Our results provide an explanation as to why GPER is not readily detected on the cell surface in some cell types and further suggest that TGN serves as the checkpoint for degradation of endocytosed GPER.
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Affiliation(s)
- Shi-Bin Cheng
- From the Division of Hematology & Oncology, Rhode Island Hospital and Brown University, Providence, Rhode Island 02903
| | - Jeffrey A. Quinn
- From the Division of Hematology & Oncology, Rhode Island Hospital and Brown University, Providence, Rhode Island 02903
| | - Carl T. Graeber
- From the Division of Hematology & Oncology, Rhode Island Hospital and Brown University, Providence, Rhode Island 02903
| | - Edward J. Filardo
- From the Division of Hematology & Oncology, Rhode Island Hospital and Brown University, Providence, Rhode Island 02903
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Nikseresht M, Seghatoleslam A, Monabati A, Talei A, Ghalati FB, Owji AA. Overexpression of the novel human gene, UBE2Q2, in breast cancer. ACTA ACUST UNITED AC 2010; 197:101-6. [PMID: 20193842 DOI: 10.1016/j.cancergencyto.2009.11.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 11/01/2009] [Accepted: 11/25/2009] [Indexed: 12/17/2022]
Abstract
The ubiquitin-proteasome pathway facilitates the degradation of damaged proteins and regulates growth and stress response. This pathway is activated in various cancers, including breast cancer. We have previously reported that the novel human gene, UBE2Q2, is a putative ubiquitin-conjugating enzyme that is located on chromosome 15 and is overexpressed in tumor mass and invasive epithelium in head and neck squamous-cell carcinoma. Here, real-time polymerase chain reaction was used to investigate the expression levels of UBE2Q2 gene in a collection of 21 breast cancer tissues matched with normal adjacent counterparts. Immunohistochemistry and Western blot testing were also performed on formalin-fixed, paraffin-embedded tissue sections by using a rabbit polyclonal antibody that we generated against an amino acid sequence predicted from the DNA sequence of UBE2Q2 gene. In the 21 cases investigated, a high increase in the expression of UBE2Q2 mRNA was found in 8 breast cancers (38.1%), a moderately increased UBE2Q2 expression was observed in 7 cases (33.3%), and no significant changes were detected in 6 cases (28.6%) of tumor samples when compared with corresponding normal tissues. Consistently, a higher level of immunoreactivity for UBE2Q2 protein was detected in invasive epithelium of cancerous tissues when compared with that in the normal epithelium. Our data suggest that the novel human gene UBE2Q2 may have implications for pathogenesis of breast cancer and could be used in molecular diagnosis purposes in the future.
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Affiliation(s)
- Mohsen Nikseresht
- Department of Biochemistry, Shiraz University of Medical Sciences, Shiraz, Iran
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Poor prognostic significance of unamplified chromosome 17 polysomy in invasive breast carcinoma. Mod Pathol 2009; 22:1044-8. [PMID: 19396150 DOI: 10.1038/modpathol.2009.61] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The human epidermal growth factor receptor 2 (HER2) oncoprotein is overexpressed in about 20% of breast cancers, with HER2 gene amplification responsible for protein overexpression in the vast majority of patients. A subset of breast cancers have chromosome 17 aneusomy, due to either 17 monosomy (a single copy of chromosome 17) or polysomy (increased copy numbers of chromosome 17). Although HER2 overexpression is an established adverse prognostic factor in breast cancer, the role of unamplified chromosome 17 polysomy is uncertain and there is a paucity of literature on the correlation of chromosome 17 aneusomy with important prognostic and predictive pathologic factors in invasive breast carcinoma. Furthermore, while patients showing HER2 amplification with or without polysomy 17 are treated with trastuzumab with or without other chemotherapy, treatment of patients with unamplified chromosome 17 polysomy is not well defined. Currently most of these patients are treated similar to patients with neither amplification nor 17 polysomy. The aim of this study was to compare some prognostic and predictive factors in invasive breast carcinoma in patients with unamplified chromosome 17 polysomy with that seen in cases with HER2 gene amplification and those with neither amplification or polysomy. We found that invasive breast carcinomas with unamplified chromosome 17 polysomy are associated with several adverse prognostic indicators such as a higher nuclear grade, mitotic activity, Nottingham score, histologic grade, tumor stage, and greater estrogen receptor negativity with a trend towards the amplified group, in contrast to patients with neither amplification or polysomy. Although most patients with unamplified 17 polysomy have a 2+ equivocal score on immunohistochemistry, a minority has a 3+ positive score. An increased adverse role for unamplified polysomy along with 3+ protein expression in some patients supports the idea that these patients should be considered for therapy with trastuzumab and/or anthracyclines.
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Loussouarn D, Campion L, Leclair F, Campone M, Charbonnel C, Ricolleau G, Gouraud W, Bataille R, Jézéquel P. Validation of UBE2C protein as a prognostic marker in node-positive breast cancer. Br J Cancer 2009; 101:166-73. [PMID: 19513072 PMCID: PMC2713693 DOI: 10.1038/sj.bjc.6605122] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Background: We recently identified and validated UBE2C RNA as a prognostic marker in 252 node-positive (N+) breast cancers by means of a microarray study. The aim of this study was to validate UBE2C protein as a prognostic marker in N+ breast cancer by immunohistochemistry (IHC). Methods: To this end, 92 paraffin-embedded blocks were used. The impact of UBE2C IHC value on metastasis-free survival (MFS) and overall survival (OS) was evaluated and compared with Ki-67 and Nottingham prognostic index (NPI) performances. Results: In accordance with genomic data, UBE2C IHC had a significant impact both on MFS and OS (hazard ratio=6.79 – P=0.002; hazard ratio=7.14 – P=0.009, respectively). Akaike information criterion proved that the prognostic power of UBE2C IHC was stronger than that of Ki-67 (and close to that of NPI). Furthermore, multivariate analyses with NPI showed that, contrary to Ki-67 IHC, UBE2C IHC remained an independent factor, both for MFS (adjusted P=0.02) and OS (adjusted P=0.04). Conclusion: We confirmed that UBE2C protein measured by IHC could be used as a prognostic marker in N+ breast cancer. The potential predictive interest of UBE2C as a marker of proteasome activity needs further investigations.
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Affiliation(s)
- D Loussouarn
- Service d'Anatomie Pathologique B, Hôpital G&R Laënnec, Bd J Monod, Nantes, Saint Herblain Cedex, France
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Wu F, Zhu S, Ding Y, Beck WT, Mo YY. MicroRNA-mediated regulation of Ubc9 expression in cancer cells. Clin Cancer Res 2009; 15:1550-7. [PMID: 19223510 DOI: 10.1158/1078-0432.ccr-08-0820] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE As an E2-conjugating enzyme for sumoylation, Ubc9 plays a critical role in sumoylation-mediated cellular pathways, ultimately impacting cell growth and cancer development. The aim of this study was to investigate the regulation of Ubc9 in cancer cells. EXPERIMENTAL DESIGN Immunohistochemistry and Western blot were used to determine Ubc9 expression in paraffin-embedded tumor tissue and frozen specimens of the matched tumors from the same patient, respectively. To establish the causal relationship between miR-30e and Ubc9 expression, we overexpressed miR-30e and then determined the resultant effects on Ubc9 expression. To determine whether miR-30e directly targets Ubc9, we did luciferase assays using luciferase reporters carrying the 3'-untranslated region (3'-UTR) of the Ubc9 gene. RESULTS We found that Ubc9 is up-regulated in breast, head and neck, and lung cancer specimens. In addition, an examination of eight pairs of matched breast tumor specimens by Western blot analysis revealed that, on average, the level of Ubc9 is 5.7-fold higher in tumor than in the matched normal breast tissue. Of interest, we present evidence that Ubc9 is subjected to posttranscriptional regulation by microRNA, and the miR-30 family, such as miR-30e, negatively regulates Ubc9 expression. In contrast to Ubc9, miR-30e is underexpressed in tumors. Moreover, ectopic expression of miR-30e suppresses cell growth, which can be partially reversed by Ubc9. Finally, using luciferase-Ubc9-3'-UTR reporters, we show that Ubc9 is a direct target for miR-30e by interactions with the putative miR-30e binding sites. CONCLUSION These results provide new insight into regulation of Ubc9 in cancer cells.
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Affiliation(s)
- Fangting Wu
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois 62794, USA
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Amemiya Y, Azmi P, Seth A. Autoubiquitination of BCA2 RING E3 ligase regulates its own stability and affects cell migration. Mol Cancer Res 2008; 6:1385-96. [PMID: 18819927 DOI: 10.1158/1541-7786.mcr-08-0094] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Accumulating evidence suggests that ubiquitination plays a role in cancer by changing the function of key cellular proteins. Previously, we isolated BCA2 gene from a library enriched for breast tumor mRNAs. The BCA2 protein is a RING-type E3 ubiquitin ligase and is overexpressed in human breast tumors. In order to deduce the biochemical and biological function of BCA2, we searched for BCA2-binding partners using human breast and fetal brain cDNA libraries and BacterioMatch two-hybrid system. We identified 62 interacting partners, the majority of which were found to encode ubiquitin precursor proteins including ubiquitin C and ubiquitin A-52. Using several deletion and point mutants, we found that the BCA2 zinc finger (BZF) domain at the NH(2) terminus specifically binds ubiquitin and ubiquitinated proteins. The autoubiquitination activity of BCA2, RING-H2 mutant, BZF mutant, and various lysine mutants of BCA2 were investigated. Our results indicate that the BCA2 protein is strongly ubiquitinated and no ubiquitination is detected with the BCA2 RING-H2 mutant, indicating that the RING domain is essential for autoubiquitination. Mutation of the K26 and K32 lysines in the BZF domain also abrogated autoubiquitination activity. Interestingly, mutation of the K232 and K260 lysines in and near the RING domain resulted in an increase in autoubiquitination activity. Additionally, in cellular migration assays, BCA2 mutants showed altered cell motility compared with wild-type BCA2. On the basis of these findings, we propose that BCA2 might be an important factor regulating breast cancer cell migration/metastasis. We put forward a novel model for BCA2 E3 ligase-mediated cell regulation.
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Affiliation(s)
- Yutaka Amemiya
- Division of Molecular and Cellular Biology, Sunnybrook Research Institute, Toronto, Ontario, Canada M4N 3M5
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Polo S, Pece S, Di Fiore PP. Exosomes from bronchoalveolar fluid of tolerized mice prevent allergic reaction. Curr Opin Cell Biol 2008; 16:156-61. [PMID: 15196558 DOI: 10.1016/j.ceb.2004.02.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Exosomes are nanovesicles originating from multivesicular bodies that are secreted by a variety of cell types. The dual capability of exosomes to promote immunity or to induce tolerance has prompted their clinical use as vehicles for vaccination against different human diseases. In the present study, the effect of allergen-specific exosomes from tolerized mice on the development of allergen-induced allergic response was determined using a mouse model. Mice were tolerized by respiratory exposure to the olive pollen allergen Ole e 1. Exosome-like vesicles were isolated from bronchoalveolar lavage fluid of the animals by the well-established filtration and ultracentrifugation procedure, characterized by electron microscopy, Western blot, and FACS analyses, and assessed in a prophylactic protocol. To this end, BALB/c mice were intranasally treated with tolerogenic exosomes or naive exosomes as control, 1 wk before sensitization/challenge to Ole e 1. Blood, lungs, and spleen were collected and analyzed for immune responses. Intranasal administration of tolerogenic exosomes inhibited the development of IgE response, Th2 cytokine production, and airway inflammation--cardinal features of allergy--and maintained specific long-term protection in vivo. This protective effect was associated with a concomitant increase in the expression of the regulatory cytokine TGF-beta. These observations demonstrate that exosomes can induce tolerance and protection against allergic sensitization in mice. Thus, exosome-based vaccines could represent an alternative to conventional therapy for allergic diseases in humans.
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Affiliation(s)
- Simona Polo
- IFOM, Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
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33
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Kaplow ME, Mannava LJ, Pimentel AC, Fermin HA, Hyatt VJ, Lee JJ, Venkatesh TR. A genetic modifier screen identifies multiple genes that interact with Drosophila Rap/Fzr and suggests novel cellular roles. J Neurogenet 2008; 21:105-51. [PMID: 17849284 DOI: 10.1080/01677060701503140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In the developing Drosophila eye, Rap/Fzr plays a critical role in neural patterning by regulating the timely exit of precursor cells. Rap/Fzr (Retina aberrant in pattern/Fizzy related) is an activator of the E3 Ubiquitin ligase, the APC (Anaphase Promoting Complex-cyclosome) that facilitates the stage specific proteolytic destruction of mitotic regulators, such as cyclins and cyclin-dependent kinases. To identify novel functional roles of Rap/Fzr, we conducted an F(1) genetic modifier screen to identify genes which interact with the partial-loss-function mutations in rap/fzr. We screened 2741 single P-element, lethal insertion lines and piggyBac lines on the second and third chromosome for dominant enhancers and suppressors of the rough eye phenotype of rap/fzr. From this screen, we have identified 40 genes that exhibit dosage-sensitive interactions with rap/fzr; of these, 31 have previously characterized cellular functions. Seven of the modifiers identified in this study are regulators of cell cycle progression with previously known interactions with rap/fzr. Among the remaining modifiers, 27 encode proteins involved in other cellular functions not directly related to cell-cycle progression. The newly identified variants fall into at least three groups based on their previously known cellular functions: transcriptional regulation, regulated proteolysis, and signal transduction. These results suggest that, in addition to cell cycle regulation, rap/fzr regulates ubiquitin-ligase-mediated protein degradation in the developing nervous system as well as in other tissues.
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Affiliation(s)
- Margarita E Kaplow
- Department of Biology, City College and The Graduate Center, City University of New York, New York, NY 10031, USA
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Abstract
Protein modifications by the covalent linkage of ubiquitin have significant involvement in many cellular processes, including stress response, oncogenesis, viral infection, transcription, protein turnover, organelle biogenesis, DNA repair, cellular differentiation, and cell cycle control. Protein ubiquitination and subsequent degradation by the proteasome require the participation of both ubiquitinating enzymes and deubiquitinating enzymes. Although deubiquitinating enzymes constitute a large family in the ubiquitin system, the study of this class of proteins is still in its infant stage. Recent studies have revealed a variety of molecular and biological functions of deubiquitinating enzymes and their association with human diseases. In this review we will discuss the possible roles that deubiquitinating enzymes may play in cancers.
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Affiliation(s)
- Jin-ming Yang
- Department of Pharmacology, The Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903, USA.
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Zandi R, Larsen AB, Andersen P, Stockhausen MT, Poulsen HS. Mechanisms for oncogenic activation of the epidermal growth factor receptor. Cell Signal 2007; 19:2013-23. [PMID: 17681753 DOI: 10.1016/j.cellsig.2007.06.023] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 06/14/2007] [Indexed: 10/23/2022]
Abstract
The Epidermal growth factor receptor (EGFR) is a membrane spanning glycoprotein, which frequently has been implicated in various cancer types. The mechanisms by which EGFR becomes oncogenic are numerous and are often specific for each cancer type. In some tumors, EGFR is activated by autocrine/paracrine growth factor loops, whereas in others activating mutations promote EGFR signaling. Overexpression and/or amplification of the EGFR gene are prevalent in many cancer types leading to aberrant EGFR signaling. In addition, failure to attenuate receptor signaling by receptor downregulation can also lead to cellular transformation. Heterodimerization of EGFR with ErbB2 inhibits downregulation of EGFR and thereby prolongs growth factor signaling. This also indicates that cross-talk between EGFR and heterologous receptor systems serves as another mechanism for oncogenic activation of EGFR. Because of its role in tumor promotion, the EGFR has been intensely studied as a therapeutic target. There are currently two major mechanisms by which the EGFR is targeted: antibodies binding to the extracellular domain of EGFR and small-molecule tyrosine-kinase inhibitors. However, tumorigenesis is a multi-step process involving several mutations, which might explain why EGFR therapeutics has only been partially successful. This highlights the importance of pinpointing the mechanisms by which EGFR becomes oncogenic in a particular cancer. In this review, each of the above mentioned mechanisms will be discussed, as a detailed molecular and genetic understanding of how EGFR contributes to the malignant phenotype might offer new promise for the design, development and clinical evaluation of future tumor-specific anticancer approaches.
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Affiliation(s)
- Roza Zandi
- Department of Radiation Biology, The Finnsen Centre, Copenhagen University Hospital, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark
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Watanabe TM, Higuchi H. Stepwise movements in vesicle transport of HER2 by motor proteins in living cells. Biophys J 2007; 92:4109-20. [PMID: 17369416 PMCID: PMC1868978 DOI: 10.1529/biophysj.106.094649] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The stepwise movements generated by myosin, dynein, and kinesin were observed in living cells in an attempt to understand the molecular mechanisms of movement within cells. First, the sequential process of the transport of vesicles, including human epidermal factor 2 receptor, after endocytosis was observed for long periods in three dimensions using quantum dots (QDs) and a three-dimensional confocal microscope. QD vesicles, after being endocytosed into the cells, moved along the membrane by transferring actin filaments and were then rapidly transported toward the nucleus along microtubules. Second, the position of vesicles was detected with a precision up to 1.9 nm and 330 micros using a new two-dimensional tracking method. The movement of the QDs transported by myosin VI lying just beneath the cell membrane consisted of 29- and 15-nm steps with a transition phase between these two steps. QD vesicles were then transported toward the nucleus or away from the nucleus toward the cell membrane with successive 8-nm steps. The stepwise movements of these motor proteins in cells were observed using new imaging methods that allowed the molecular mechanisms underlying traffic to and from the membrane to be determined.
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Affiliation(s)
- Tomonobu M Watanabe
- Biomedical and Engineering Research Organization, Tohoku University, Sendai, Japan
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Lu Z, Wu H, Mo YY. Regulation of bcl-2 expression by Ubc9. Exp Cell Res 2006; 312:1865-75. [PMID: 16566921 DOI: 10.1016/j.yexcr.2006.02.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 02/15/2006] [Accepted: 02/15/2006] [Indexed: 11/30/2022]
Abstract
Posttranslational modifications mediated by ubiquitin-like proteins have been implicated in regulating a variety of cellular pathways. Although small ubiquitin-like modifier (SUMO) is a new member of this family, it has caught a great deal of attention recently because of its novel and distinguished functions. Sumoylation is a multiple-step process, involving maturation, activation, conjugation and ligation. Ubc9 is an E2 conjugating enzyme essential for sumoylation. We have previously shown that suppression of sumoylation by a dominant negative Ubc9 mutant (Ubc9-DN) in the estrogen receptor (ER) positive MCF-7 cells is associated with alterations of tumor cell's response to anticancer drugs as well as tumor growth in a xenograft mouse carcinoma model. To dissect the underlying mechanism of Ubc9-associated alterations of drug responsiveness and tumor growth, we profiled gene expression for the cells expressing wild type Ubc9 (Ubc9-WT) and Ubc9-DN. We found that several tumorigenesis-related genes were downregulated in the Ubc9-DN cells. Within this group, we found that over 10 genes are known to be regulated by ER. Experiments using the estrogen response element fused to the luciferase reporter showed that the basal level of luciferase activity was significantly reduced in the Ubc9-DN cells when compared to the vector alone or the Ubc9-WT cells. Furthermore, we found that both the stability and the subcellular localization of steroid hormone receptor coactivator-1 (SRC-1) were altered in the Ubc9-DN cells. Together, these results suggest that Ubc9 might regulate bcl-2 expression through the ER signaling pathway, which ultimately contributes to the alterations of drug responsiveness and tumor growth.
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Affiliation(s)
- Zhaohui Lu
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, 801 N. Rutledge, PO Box 19626, Springfield, IL 62794, USA
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38
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Ricolleau G, Charbonnel C, Lodé L, Loussouarn D, Joalland MP, Bogumil R, Jourdain S, Minvielle S, Campone M, Déporte-Fety R, Campion L, Jézéquel P. Surface-enhanced laser desorption/ionization time of flight mass spectrometry protein profiling identifies ubiquitin and ferritin light chain as prognostic biomarkers in node-negative breast cancer tumors. Proteomics 2006; 6:1963-75. [PMID: 16470659 DOI: 10.1002/pmic.200500283] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Novel prognostic biomarkers are imperatively needed to help direct treatment decisions by typing subgroups of node-negative breast cancer patients. The current study has used a proteomic approach of SELDI-TOF-MS screening to identify differentially cytosolic expressed proteins with a prognostic impact in 30 node-negative breast cancer patients with no relapse versus 30 patients with metastatic relapse. The data analysis took into account 73 peaks, among which 2 proved, by means of univariate Cox regression, to have a good cumulative prognostic-informative power. Repeated random sampling (n = 500) was performed to ensure the reliability of the peaks. Optimized thresholds were then computed to use both peaks as risk factors and, adding them to the St. Gallen ones, improve the prognostic classification of node-negative breast cancer patients. Identification of ubiquitin and ferritin light chain (FLC), corresponding to the two peaks of interest, was obtained using ProteinChip LDI-Qq-TOF-MS. Differential expression of the two proteins was further confirmed by Western blotting analyses and immunohistochemistry. SELDI-TOF-MS protein profiling clearly showed that a high level of cytosolic ubiquitin and/or a low level of FLC were associated with a good prognosis in breast cancer.
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MESH Headings
- Apoferritins
- Biomarkers, Tumor/analysis
- Biomarkers, Tumor/isolation & purification
- Biomarkers, Tumor/metabolism
- Blotting, Western
- Breast Neoplasms/diagnosis
- Breast Neoplasms/pathology
- Breast Neoplasms/surgery
- Carcinoma, Ductal, Breast/diagnosis
- Carcinoma, Ductal, Breast/pathology
- Carcinoma, Ductal, Breast/surgery
- Computational Biology
- Disease-Free Survival
- Female
- Ferritins
- Follow-Up Studies
- France/epidemiology
- Humans
- Immunohistochemistry
- Mammography
- Mass Spectrometry/methods
- Neoplasm Recurrence, Local
- Peptides/analysis
- Peptides/isolation & purification
- Peptides/metabolism
- Prognosis
- Protein Array Analysis/methods
- Proteomics
- Radiography, Thoracic
- Retrospective Studies
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
- Time Factors
- Ubiquitin/analysis
- Ubiquitin/isolation & purification
- Ubiquitin/metabolism
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Affiliation(s)
- Gabriel Ricolleau
- Département de Biologie Oncologique, Centre de Lutte Contre le Cancer René Gauducheau, Nantes, Saint Herblain Cedex, France
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39
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Stokes A, Wakano C, Koblan-Huberson M, Adra CN, Fleig A, Turner H. TRPA1 is a substrate for de-ubiquitination by the tumor suppressor CYLD. Cell Signal 2006; 18:1584-94. [PMID: 16500080 DOI: 10.1016/j.cellsig.2005.12.009] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Revised: 12/24/2005] [Accepted: 12/26/2005] [Indexed: 11/25/2022]
Abstract
Certain TRP cation channels confer the ability to sense environmental stimuli (heat, cold, pressure, osmolarity) across physiological and pathophysiological ranges. TRPA1 is a TRP-related channel that responds to cold temperatures, and pungent compounds that include the cold-mimetic icilin and cannabinoids. The initial report of TRPA1 as a transformation-associated gene product in lung epithelia is at odds with subsequent descriptions of a tissue distribution for TRPA1 that is restricted to sensory neurons. Here, we report that the human TRPA1 protein is widely expressed outside the CNS, and is indeed dys-regulated during oncogenic transformation. We describe that TRPA1 associates with the tumor-suppressor protein CYLD. TRPA1 is a novel substrate for the de-ubiquitinating activity of CYLD, and this de-ubiquitination has the net effect of increasing the cellular pool of TRPA1 proteins. Oncogenic mutations in the CYLD gene may therefore be predicted to alter cellular levels of TRPA1.
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Affiliation(s)
- Alexander Stokes
- Laboratory of Cell Biology and Immunology, Center for Biomedical Research at Queen's Medical Center, Honolulu, HI 96813, USA
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40
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Tripathi MK, Chaudhuri G. Down-regulation of UCRP and UBE2L6 in BRCA2 knocked-down human breast cells. Biochem Biophys Res Commun 2005; 328:43-8. [PMID: 15670748 PMCID: PMC3085986 DOI: 10.1016/j.bbrc.2004.12.142] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Indexed: 10/26/2022]
Abstract
To understand the effects of the transient ablation of BRCA2 gene expression in dividing human breast cells, we transiently knocked down BRCA2 mRNA in HMEC and other cells. Microarray analysis of mRNAs revealed the down-regulation of the mRNAs of ubiquitin cross-reacting protein (UCRP) and the E2 enzyme that help conjugating UCRP to its target proteins, namely UBE2L6 (UbcH8), in BRCA2 ablated cells. UCRP is an interferon regulated protein, involved in cell growth and cell cycle events by participating in the degradation/modulation of cell cycle regulatory proteins. Quantitative-PCR and Northern analysis confirmed down-regulation of UCRP and UBE2L6 with BRCA2 knockdown, respectively. Since UCRP and UCRPylation have critical roles in the innate immunity against viral infection and during pregnancy, our observation may indicate new roles of the BRCA2 protein.
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41
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Abstract
The post-translational modifications ubiquitination and sumoylation have been implicated in regulating many critical cellular pathways. Like ubiquitination, sumoylation is a multistep process involving maturation, activation, conjugation and deconjugation. Ubc9 is a sole E2-conjugating enzyme essential for sumoylation. We have previously shown that alterations of Ubc9 expression affect tumor drug responsiveness. However, it is not clear whether there is any link between sumoylation and tumorigenesis, even though alterations of the ubiquitination pathway can lead to the development of cancer. In this study, we found that Ubc9 expression levels were elevated in ovarian tumors compared to the matched normal ovarian specimens, suggesting that Ubc9 may play a role in tumorigenesis. To test this, we overexpressed a dominant-negative mutant of Ubc9 (Ubc9-DN) and wild-type Ubc9 (Ubc9-WT) in the MCF-7 human breast tumor cells. Inoculating these cells as xenografts in mice revealed that tumors expressing Ubc9-WT grew better than the vector control, while tumors expressing Ubc9-DN exhibited reduced growth. This pattern was also seen in these cells when grown in culture. To better understand the mechanism behind this observation, we profiled gene expressions in these cells by microarray analysis and found alterations in expression of the pro-oncogene bcl-2 in these Ubc9-DN- and Ubc9-WT-expressing cells. Consistent with the bcl-2 results, subsequent studies revealed a higher rate of apoptosis and poor survival for the MCF-7 cells expressing Ubc9-DN, which are associated with downregulation of bcl-2. Together, these results suggest a role for Ubc9 in tumorigenesis at least partially through regulation of bcl-2 expression.
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Affiliation(s)
- Yin-Yuan Mo
- Department of Biopharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA.
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42
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Abstract
The proteasome is a multicatalytic protein complex whose principal task is the degradation of a large array of proteins within the cell. Its substrates include proteins involved in cell cycle regulation, tumor suppression, apoptosis, transcription, and angiogenesis, among others. This makes the inhibition of the proteasome a promising novel therapeutic approach to cancer treatment. Bortezomib (Velcade) is the first proteasome inhibitor to have shown anti-cancer activity and reached clinical trials. Preclinical and early clinical trials in both solid tumors and hematological malignancies demonstrate that bortezomib is a relatively well-tolerated and active agent, either alone or in combination with traditional chemotherapeutic drugs. Clinical trials that may help delineate the role of bortezomib in the treatment solid tumors either as single agent or in combination are ongoing.
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Affiliation(s)
- David J Park
- Division of Medical Oncology, University of Southern California/Norris Comprehensive Cancer Center, Los Angeles, USA
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