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Zhang Y, Liang L, Li Z, Huang Y, Jiang M, Zou B, Xu Y. Polyadenosine diphosphate-ribose polymerase inhibitors: advances, implications, and challenges in tumor radiotherapy sensitization. Front Oncol 2023; 13:1295579. [PMID: 38111536 PMCID: PMC10726039 DOI: 10.3389/fonc.2023.1295579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 11/22/2023] [Indexed: 12/20/2023] Open
Abstract
Polyadenosine diphosphate-ribose polymerase (PARP) is a key modifying enzyme in cells, which participates in single-strand break repair and indirectly affects double-strand break repair. PARP inhibitors have shown great potential in oncotherapy by exploiting DNA damage repair pathways, and several small molecule PARP inhibitors have been approved by the U.S. Food and Drug Administration for treating various tumor types. PARP inhibitors not only have significant antitumor effects but also have some synergistic effects when combined with radiotherapy; therefore they have potential as radiation sensitizers. Here, we reviewed the advances and implications of PARP inhibitors in tumor radiotherapy sensitization. First, we summarized the multiple functions of PARP and the mechanisms by which its inhibitors exert antitumor effects. Next, we discuss the immunomodulatory effects of PARP and its inhibitors in tumors. Then, we described the theoretical basis of using PARP inhibitors in combination with radiotherapy and outlined their importance in oncological radiotherapy. Finally, we reviewed the current challenges in this field and elaborated on the future applications of PARP inhibitors as radiation sensitizers. A comprehensive understanding of the mechanism, optimal dosing, long-term safety, and identification of responsive biomarkers remain key challenges to integrating PARP inhibition into the radiotherapy management of cancer patients. Therefore, extensive research in these areas would facilitate the development of precision radiotherapy using PARP inhibitors to improve patient outcomes.
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Affiliation(s)
- Yi Zhang
- Department of Radiation Oncology, Division of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Lijie Liang
- Division of Head & Neck Tumor Multimodality Treatment, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Zheng Li
- Department of Radiation Oncology, Division of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Ying Huang
- College of Management, Sichuan Agricultural University, Chengdu, China
| | - Ming Jiang
- Division of Head & Neck Tumor Multimodality Treatment, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Bingwen Zou
- Department of Radiation Oncology, Division of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Yong Xu
- Department of Radiation Oncology, Division of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
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2
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Liu Q, Bode AM, Chen X, Luo X. Metabolic reprogramming in nasopharyngeal carcinoma: Mechanisms and therapeutic opportunities. Biochim Biophys Acta Rev Cancer 2023; 1878:189023. [PMID: 37979733 DOI: 10.1016/j.bbcan.2023.189023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/20/2023]
Abstract
The high prevalence of metabolic reprogramming in nasopharyngeal carcinoma (NPC) offers an abundance of potential therapeutic targets. This review delves into the distinct mechanisms underlying metabolic reprogramming in NPC, including enhanced glycolysis, nucleotide synthesis, and lipid metabolism. All of these changes are modulated by Epstein-Barr virus (EBV) infection, hypoxia, and tumor microenvironment. We highlight the role of metabolic reprogramming in the development of NPC resistance to standard therapies, which represents a challenging barrier in treating this malignancy. Furthermore, we dissect the state of the art in therapeutic strategies that target these metabolic changes, evaluating the successes and failures of clinical trials and the strategies to tackle resistance mechanisms. By providing a comprehensive overview of the current knowledge and future directions in this field, this review sets the stage for new therapeutic avenues in NPC.
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Affiliation(s)
- Qian Liu
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Oncotarget Gene, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China; Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Cancer Research Institute, School of Basic Medicine, Central South University, Changsha, Hunan 410078, PR China
| | - Ann M Bode
- The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Xue Chen
- Early Clinical Trial Center, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China.
| | - Xiangjian Luo
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Oncotarget Gene, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China; Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Cancer Research Institute, School of Basic Medicine, Central South University, Changsha, Hunan 410078, PR China; Key Laboratory of Biological Nanotechnology of National Health Commission, Central South University, Changsha, Hunan 410078, China.
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3
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Juarez-Vignon Whaley JJ, Afkhami M, Onyshchenko M, Massarelli E, Sampath S, Amini A, Bell D, Villaflor VM. Recurrent/Metastatic Nasopharyngeal Carcinoma Treatment from Present to Future: Where Are We and Where Are We Heading? Curr Treat Options Oncol 2023; 24:1138-1166. [PMID: 37318724 PMCID: PMC10477128 DOI: 10.1007/s11864-023-01101-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2023] [Indexed: 06/16/2023]
Abstract
OPINION STATEMENT Nasopharyngeal carcinoma (NPC) is distinct in its anatomic location and biology from other epithelial head and neck cancer (HNC). There are 3 WHO subtypes, which considers the presence of Epstein-Barr virus (EBV) and other histopathology features. Despite the survival benefit obtained from modern treatment modalities and techniques specifically in the local and locally advanced setting, a number of patients with this disease will recur and subsequently die of distant metastasis, locoregional relapse, or both. In the recurrent setting, the ideal therapy approach continues to be a topic of discussion and current recommendations are platinum-based combination chemotherapy. Phase III clinical trials which led to the approval of pembrolizumab or nivolumab for head and neck squamous cell carcinoma (HNSCC) specifically excluded NPC. No immune checkpoint inhibitor therapy, to date, has been approved by the FDA to treat NPC although the National Comprehensive Cancer Network (NCCN) recommendations do include use of these agents. Hence, this remains the major challenge for treatment options. Nasopharyngeal carcinoma is challenging as it is really 3 different diseases, and much research is required to determine best options and sequencing of those options. This article is going to address the data to date and discuss ongoing research in EBV + and EBV - inoperable recurrent/metastatic NPC patients.
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Affiliation(s)
- Juan Jose Juarez-Vignon Whaley
- Health Science Research Center, Faculty of Health Science, Universidad Anahuac Mexico, State of Mexico, Naucalpan de Juárez, Mexico
| | - Michelle Afkhami
- Department of Pathology, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
| | - Mykola Onyshchenko
- Department of Medical Oncology, City of Hope Comprehensive Cancer Center, Duarte, 1500 East Duarte Road. , Duarte, CA, 91010, USA
| | - Erminia Massarelli
- Department of Medical Oncology, City of Hope Comprehensive Cancer Center, Duarte, 1500 East Duarte Road. , Duarte, CA, 91010, USA
| | - Sagus Sampath
- Department of Radiation Oncology, City of Hope Comprehensive Cancer Center Duarte, Duarte, CA, USA
| | - Arya Amini
- Department of Radiation Oncology, City of Hope Comprehensive Cancer Center Duarte, Duarte, CA, USA
| | - Diana Bell
- Department of Pathology, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
| | - Victoria M Villaflor
- Department of Medical Oncology, City of Hope Comprehensive Cancer Center, Duarte, 1500 East Duarte Road. , Duarte, CA, 91010, USA.
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4
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Chou J, Kaller M, Jaeckel S, Rokavec M, Hermeking H. AP4 suppresses DNA damage, chromosomal instability and senescence via inducing MDC1/Mediator of DNA damage Checkpoint 1 and repressing MIR22HG/miR-22-3p. Mol Cancer 2022; 21:120. [PMID: 35624466 PMCID: PMC9137087 DOI: 10.1186/s12943-022-01581-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/22/2022] [Indexed: 12/11/2022] Open
Abstract
Background AP4 (TFAP4) encodes a basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factor and is a direct target gene of the oncogenic transcription factor c-MYC. Here, we set out to determine the relevance of AP4 in human colorectal cancer (CRC) cells. Methods A CRISPR/Cas9 approach was employed to generate AP4-deficient CRC cell lines with inducible expression of c-MYC. Colony formation, β-gal staining, immunofluorescence, comet and homologous recombination (HR) assays and RNA-Seq analysis were used to determine the effects of AP4 inactivation. qPCR and qChIP analyses was performed to validate differentially expressed AP4 targets. Expression data from CRC cohorts was subjected to bioinformatics analyses. Immunohistochemistry was used to evaluate AP4 targets in vivo. Ap4-deficient APCmin/+ mice were analyzed to determine conservation. Immunofluorescence, chromosome and micronuclei enumeration, MTT and colony formation assays were used to determine the effects of AP4 inactivation and target gene regulation on chromosomal instability (CIN) and drug sensitivity. Results Inactivation of AP4 in CRC cell lines resulted in increased spontaneous and c-MYC-induced DNA damage, chromosomal instability (CIN) and cellular senescence. AP4-deficient cells displayed increased expression of the long non-coding RNA MIR22HG, which encodes miR-22-3p and was directly repressed by AP4. Furthermore, Mediator of DNA damage Checkpoint 1 (MDC1), a central component of the DNA damage response and a known target of miR-22-3p, displayed decreased expression in AP4-deficient cells. Accordingly, MDC1 was directly induced by AP4 and indirectly by AP4-mediated repression of miR-22-3p. Adenomas and organoids from Ap4-deficient APCmin/+ mice displayed conservation of these regulations. Inhibition of miR-22-3p or ectopic MDC1 expression reversed the increased senescence, DNA damage, CIN and defective HR observed in AP4-deficient CRC cells. AP4-deficiency also sensitized CRC cells to 5-FU treatment, whereas ectopic AP4 conferred resistance to 5-FU in a miR-22-3p and MDC1-dependent manner. Conclusions In summary, AP4, miR-22-3p and MDC1 form a conserved and coherent, regulatory feed-forward loop to promote DNA repair, which suppresses DNA damage, senescence and CIN, and contributes to 5-FU resistance. These findings explain how elevated AP4 expression contributes to development and chemo-resistance of colorectal cancer after c-MYC activation. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12943-022-01581-1.
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Affiliation(s)
- Jinjiang Chou
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University, Thalkirchner Strasse 36, 80337, Munich, Germany
| | - Markus Kaller
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University, Thalkirchner Strasse 36, 80337, Munich, Germany
| | - Stephanie Jaeckel
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University, Thalkirchner Strasse 36, 80337, Munich, Germany
| | - Matjaz Rokavec
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University, Thalkirchner Strasse 36, 80337, Munich, Germany
| | - Heiko Hermeking
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University, Thalkirchner Strasse 36, 80337, Munich, Germany. .,German Cancer Consortium (DKTK), Partner site Munich, Munich, Germany. .,German Cancer Research Center (DKFZ), Heidelberg, Germany.
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5
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SFN Enhanced the Radiosensitivity of Cervical Cancer Cells via Activating LATS2 and Blocking Rad51/MDC1 Recruitment to DNA Damage Site. Cancers (Basel) 2022; 14:cancers14081872. [PMID: 35454780 PMCID: PMC9026704 DOI: 10.3390/cancers14081872] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/05/2022] [Accepted: 03/30/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Radiotherapy is the main treatment for cervical cancer patients in advanced stages. However a considerable number of patients are not sensitive to radiotherapy. Dysregulation of DNA double-strand break (DSB) repair is characteristic of cancer cells in a radiotherapy-resistance state. The aim of this study is to explore Sulforaphane (SFN) downstream target and the radiotherapy sensitization mechanism in cervical cancer. We identified SFN as cervical cancer cells radiotherapy sensitizer and LATS2 served as a downstream target of SFN treatment. SFN treatment resulted in the inhibition of the homologous recombination (HR) pathway, and LATS2 has an indispensable contribution to this SFN-facilitated radiotherapy sensitization. Abstract Background: Sulforaphane (SFN) is one kind of phytochemical anticancer drug. It inhibits cancer cell proliferation and promotes cell apoptosis while the mechanism behind is still uncertain. We aimed to explore its downstream target and the radiotherapy sensitization mechanism in cervical cancer. Methods: We treated established cervical cancer cells line (SiHa, HeLa, C33A) with SFN followed by irradiation, and explored its survival, apoptosis, and DNA damage repair in vitro and validated the radiosensitivity of SFN treatment in vivo. We conducted mRNA sequencing to identify differentially expressed mRNAs after SFN treatment. We further investigated SFN downstream target and its involvement in DNA damage repair under irradiation. Results: We found that SFN inhibited the survival of cervical cancer cells under radiotherapy treatment in vitro and prolonged the survival period after radiotherapy in the mouse tumorigenic model. SFN increased the protein expression of LATS2 and promoted apoptosis of cervical cancer cells. Overexpressed LATS2 decreased the cellular survival rate of cervical cancer cells. Additionally, SFN treatment and LATS2 overexpression prevented MDC1 and Rad51 from accumulating in the nucleus in cervical cancer cells after being exposed to ionized radiation. LATS2 loss intervened with SFN-alleviated RAD51 and MDC1 nucleus accumulation and resumed the repairment of DNA damage. Conclusion: We identified SFN as cervical cancer cells radiotherapy sensitizer and LATS2 served as a downstream target of SFN treatment. SFN treatment resulted in the inhibition of the homologous recombination (HR) pathway, and LATS2 has an indispensable contribution to this SFN-facilitated radiotherapy sensitization.
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6
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Copper enhances genotoxic drug resistance via ATOX1 activated DNA damage repair. Cancer Lett 2022; 536:215651. [DOI: 10.1016/j.canlet.2022.215651] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/13/2022] [Accepted: 03/16/2022] [Indexed: 12/11/2022]
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7
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Induction of Apoptosis, Inhibition of MCL-1, and VEGF-A Expression Are Associated with the Anti-Cancer Efficacy of Magnolol Combined with Regorafenib in Hepatocellular Carcinoma. Cancers (Basel) 2021; 13:cancers13092066. [PMID: 33922992 PMCID: PMC8123296 DOI: 10.3390/cancers13092066] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/12/2022] Open
Abstract
While regorafenib was approved for the treatment of advanced HCC in 2017, with a partial response and survival benefit; other combination agents to facilitate the efficacy of regorafenib still need to be explored. Magnolol is a potential natural anti-tumor compound for many types of cancers. Combination indexes calculated on the basis of both in vitro and in vivo models have indicated a synergistic effect of the combination of regorafenib and magnolol. The overexpression of the VEGF-A protein significantly diminished regorafenib's inhibition of cell viability, while the transient knockdown of VEGF-A by siRNA effectively sensitized HCC cells to regorafenib. In addition, the inhibition of MCL-1 by siRNA combined with regorafenib allowed for a significantly greater inhibition of cell growth, compared to regorafenib alone. A lower protein expression level for VEGF-A and MCL-1 was found for the combination treatment of HCC in vitro and in vivo. A superior metastasis inhibition was also found in the combination group, as compared to the single-treatment groups, using a transwell assay, wound healing assay, and Western blotting. The caspase-dependent and -independent and DNA damage effects, as determined by flow cytometry and a comet assay, were increased by the combination therapy. Taken together, magnolol sensitized HCC to regorafenib, which was correlated with the reduction of VEGF-A and MCL-1 and the induction of apoptosis.
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8
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Zhou P, Wang J, Mishail D, Wang CY. Recent advancements in PARP inhibitors-based targeted cancer therapy. PRECISION CLINICAL MEDICINE 2020; 3:187-201. [PMID: 32983586 PMCID: PMC7501589 DOI: 10.1093/pcmedi/pbaa030] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/27/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022] Open
Abstract
Poly(ADP-ribose) polymerase inhibitors (PARPi) are a new class of agents with unparalleled clinical achievement for driving synthetic lethality in BRCA-deficient cancers. Recent FDA approval of PARPi has motivated clinical trials centered around the optimization of PARPi-associated therapies in a variety of BRCA-deficient cancers. This review highlights recent advancements in understanding the molecular mechanisms of PARP ‘trapping’ and synthetic lethality. Particular attention is placed on the potential extension of PARPi therapies from BRCA-deficient patients to populations with other homologous recombination-deficient backgrounds, and common characteristics of PARPi and non-homologous end-joining have been elucidated. The synergistic antitumor effect of combining PARPi with various immune checkpoint blockades has been explored to evaluate the potential of combination therapy in attaining greater therapeutic outcome. This has shed light onto the differing classifications of PARPi as well as the factors that result in altered PARPi activity. Lastly, acquired chemoresistance is a crucial issue for clinical application of PARPi. The molecular mechanisms underlying PARPi resistance and potential overcoming strategies are discussed.
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Affiliation(s)
- Ping Zhou
- Laboratory of Molecular Signaling, Division of Oral Biology and Medicine, School of Dentistry, UCLA, Los Angeles, CA 90095, USA
| | - Justin Wang
- Laboratory of Molecular Signaling, Division of Oral Biology and Medicine, School of Dentistry, UCLA, Los Angeles, CA 90095, USA
| | - Daniel Mishail
- Laboratory of Molecular Signaling, Division of Oral Biology and Medicine, School of Dentistry, UCLA, Los Angeles, CA 90095, USA
| | - Cun-Yu Wang
- Laboratory of Molecular Signaling, Division of Oral Biology and Medicine, School of Dentistry, UCLA, Los Angeles, CA 90095, USA
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9
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Ruff SE, Logan SK, Garabedian MJ, Huang TT. Roles for MDC1 in cancer development and treatment. DNA Repair (Amst) 2020; 95:102948. [PMID: 32866776 DOI: 10.1016/j.dnarep.2020.102948] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/28/2022]
Abstract
The DNA damage response (DDR) is necessary to maintain genome integrity and prevent the accumulation of oncogenic mutations. Consequently, proteins involved in the DDR often serve as tumor suppressors, carrying out the crucial task of keeping DNA fidelity intact. Mediator of DNA damage checkpoint 1 (MDC1) is a scaffold protein involved in the early steps of the DDR. MDC1 interacts directly with γ-H2AX, the phosphorylated form of H2AX, a commonly used marker for DNA damage. It then propagates the phosphorylation of H2AX by recruiting ATM kinase. While the function of MDC1 in the DDR has been reviewed previously, its role in cancer has not been reviewed, and numerous studies have recently identified a link between MDC1 and carcinogenesis. This includes MDC1 functioning as a tumor suppressor, with its loss serving as a biomarker for cancer and contributor to drug sensitivity. Studies also indicate that MDC1 operates outside of its traditional role in DDR, and functions as a co-regulator of nuclear receptor transcriptional activity, and that mutations in MDC1 are present in tumors and can also cause germline predisposition to cancer. This review will discuss reports that link MDC1 to cancer and identify MDC1 as an important player in tumor formation, progression, and treatment. We also discuss mechanisms by which MDC1 levels are regulated and how this contributes to tumor formation.
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Affiliation(s)
- Sophie E Ruff
- Department of Microbiology, New York University School of Medicine, New York, NY, 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Susan K Logan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA; Department of Urology, New York University School of Medicine, New York, NY, 10016, USA
| | - Michael J Garabedian
- Department of Microbiology, New York University School of Medicine, New York, NY, 10016, USA; Department of Urology, New York University School of Medicine, New York, NY, 10016, USA.
| | - Tony T Huang
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA.
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10
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Zhang X, Hu F, Liu L, Xu B. Effect of silencing of mediator of DNA damage checkpoint protein 1 on the growth of oral squamous cell carcinoma in vitro and in vivo. Eur J Oral Sci 2019; 127:494-499. [PMID: 31786813 DOI: 10.1111/eos.12662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2019] [Indexed: 12/24/2022]
Abstract
Mediator of DNA damage checkpoint protein 1 (MDC1) is involved in DNA damage repair and has been linked to tumor invasion, metastasis, and prognosis. This study investigated the effects of MDC1 in oral squamous cell carcinoma (OSCC) in vitro and in vivo. RNA interference-mediated knockdown of MDC1 was performed in two OSCC cell lines (Tca-8113 and KB). Real-time PCR and western blotting were performed to determine expression of mRNA and protein, respectively, of MDC1. Cell viability was assessed using the MTT assay. Colony-formation assays were performed by staining with 0.5% crystal violet. Cell migration and invasion were detected by Transwell assays. The role of MDC1 in OSCC was examined in vivo via injection of Tca-8113 cells transfected with MDC1 small interfering (si)RNA or negative-control siRNA into a mouse xenograft model of OSCC. Our results showed that MDC1 knockdown decreased cell proliferation. Inhibition of MDC1 decreased colony formation of Tca-8113 and KB cells by 62% and 68%, respectively, and MDC1 knockdown reduced the number of migratory and invasive cells compared with the control group. Moreover, the xenograft mouse model of MDC1 knockdown showed reduced tumor growth. Our study suggests that MDC1 plays a role in tumorigenesis and might be a potential target for the treatment of patients with OSCC.
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Affiliation(s)
- Xiaoying Zhang
- Department of Stomatology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Fengling Hu
- Department of Stomatology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Liuhui Liu
- Department of Stomatology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Bin Xu
- Department of Stomatology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
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11
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Lu Q, Zhang FL, Lu DY, Shao ZM, Li DQ. USP9X stabilizes BRCA1 and confers resistance to DNA-damaging agents in human cancer cells. Cancer Med 2019; 8:6730-6740. [PMID: 31512408 PMCID: PMC6825982 DOI: 10.1002/cam4.2528] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/10/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022] Open
Abstract
BRCA1, a multifunctional protein with an important role in DNA double‐strand break repair by homologous recombination (HR), is subjected to ubiquitin‐dependent degradation. To date, several E3 ubiquitin ligases have been identified to govern BRCA1 stability, but the deubiquitinase that counteracts its turnover remains undefined. In this study, we report that the ubiquitin‐specific protease 9X (USP9X) is a bona fide deubiquitinase for BRCA1 in human cancer cells. Reciprocal immunoprecipitation assays demonstrated that USP9X interacted with BRCA1. Depletion of USP9X by short interfering RNAs or inhibition of USP9X by the small‐molecular inhibitor WP1130 significantly reduced BRCA1 protein abundance, without affecting its mRNA levels. In contrast, overexpression of wild‐type USP9X, but not its deubiquitinase activity‐defective mutant (C1566S), resulted in an upregulation of BRCA1 protein levels. Moreover, USP9X depletion reduced the half‐life of BRCA1, accompanied by an increase in its ubiquitination. HR assays showed that knockdown of USP9X significantly reduced HR efficiency, which was partially rescued by reintroduction of BRCA1 into USP9X‐depleted cells. In support of these findings, USP9X knockdown significantly enhanced sensitivity to PARP inhibitor Olaparib and methyl methanesulfonate (MMS). Collectively, these results establish USP9X as a deubiquitinase for BRCA1 and reveal a previously unrecognized role of USP9X in the regulation of HR repair and the sensitivity of cancer cells to DNA‐damaging agents.
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Affiliation(s)
- Qin Lu
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Fang-Lin Zhang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Cancer Institute, Shanghai Medical College, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Da-Yun Lu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Zhi-Ming Shao
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Cancer Institute, Shanghai Medical College, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Breast Cancer in Shanghai, Shanghai Medical College, Fudan University, Shanghai, China
| | - Da-Qiang Li
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.,Cancer Institute, Shanghai Medical College, Fudan University, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.,Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Breast Cancer in Shanghai, Shanghai Medical College, Fudan University, Shanghai, China
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