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Song J, Cui D, Wang J, Qin J, Wang S, Wang Z, Zhai X, Ma H, Ma D, Liu Y, Jin B, Liu Z. Overexpression of HMGA1 confers radioresistance by transactivating RAD51 in cholangiocarcinoma. Cell Death Discov 2021; 7:322. [PMID: 34716319 PMCID: PMC8556338 DOI: 10.1038/s41420-021-00721-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/02/2021] [Accepted: 10/13/2021] [Indexed: 01/16/2023] Open
Abstract
Cholangiocarcinomas (CCAs) are rare but aggressive tumors of the bile ducts. CCAs are often diagnosed at an advanced stage and respond poorly to current conventional radiotherapy and chemotherapy. High mobility group A1 (HMGA1) is an architectural transcription factor that is overexpressed in multiple malignant tumors. In this study, we showed that the expression of HMGA1 is frequently elevated in CCAs and that the high expression of this gene is associated with a poor prognosis. Functionally, HMGA1 promotes CCA cell proliferation/invasion and xenograft tumor growth. Furthermore, HMGA1 transcriptionally activates RAD51 by binding to its promoter through two HMGA1 response elements. Notably, overexpression of HMGA1 promotes radioresistance whereas its knockdown causes radiosensitivity of CCA cells to X-ray irradiation. Moreover, rescue experiments reveal that inhibition of RAD51 reverses the effect of HMGA1 on radioresistance and proliferation/invasion. These findings suggest that HMGA1 functions as a novel regulator of RAD51 and confers radioresistance in cholangiocarcinoma.
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Affiliation(s)
- Jianping Song
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China.,Department of Organ Transplantation, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Donghai Cui
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Jing Wang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Junchao Qin
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Shourong Wang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Zixiang Wang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Xiangyu Zhai
- Department of Organ Transplantation, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Huan Ma
- Department of Organ Transplantation, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Delin Ma
- Department of Organ Transplantation, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China
| | - Yanfeng Liu
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China.
| | - Bin Jin
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China. .,Department of Organ Transplantation, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China.
| | - Zhaojian Liu
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Department of Hepatobiliary Surgery, Qilu Hospital, Cheeloo College of Medicine, Shandong University, 107 Wenhua Xi Road, 250012, Jinan, Shandong Province, China.
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Kara A, Özgür A, Nalbantoğlu S, Karadağ A. DNA repair pathways and their roles in drug resistance for lung adenocarcinoma. Mol Biol Rep 2021; 48:3813-3825. [PMID: 33856604 DOI: 10.1007/s11033-021-06314-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/24/2021] [Indexed: 01/24/2023]
Abstract
Lung cancer is the leading cancer type of death rate. The lung adenocarcinoma subtype is responsible for almost half of the total lung cancer deaths. Despite the improvements in cancer treatment in recent years, lung adenocarcinoma patients' overall survival rate remains poor. Immunetherapy and chemotherapy are two of the most widely used options for the treatment of cancer. Although many cancer types initially respond to these treatments, the development of resistance is inevitable. The rapid development of drug resistance mainly characterizes lung adenocarcinoma. Despite being the subject of many studies in recent years, the resistance initiation and progression mechanism is still unclear. In this review, we have examined the role of the primary DNA repair pathways (non-homologous end joining (NHEJ) pathway, homologous-recombinant repair (HR) pathway, base excision repair (BER) pathway, and nucleotide excision repair (NER) pathway and transactivation mechanisms of tumor protein 53 (TP53) in drug resistance development. This review suggests that mentioned pathways have essential roles in developing the resistance against chemotherapy and immunotherapy in lung adenocarcinoma patients.
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Affiliation(s)
- Altan Kara
- Molecular Oncology Laboratory, Genetic Engineering and Biotechnology Institute, TUBITAK Marmara Research Center, Kocaeli, Turkey.
| | - Aykut Özgür
- Laboratory and Veterinary Health Program, Department of Veterinary Medicine, Artova Vocational School, Tokat Gaziosmanpaşa University, Tokat, Turkey
| | - Sinem Nalbantoğlu
- Molecular Oncology Laboratory, Genetic Engineering and Biotechnology Institute, TUBITAK Marmara Research Center, Kocaeli, Turkey
| | - Abdullah Karadağ
- Molecular Oncology Laboratory, Genetic Engineering and Biotechnology Institute, TUBITAK Marmara Research Center, Kocaeli, Turkey
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Polymorphic Variants in 5'-UTR Regions of the RAD51 Gene are Associated With RAD51 Expression and Triple-Negative Breast Cancer (TNBC): A Case-Control Study. Appl Immunohistochem Mol Morphol 2021; 29:270-276. [PMID: 33417321 DOI: 10.1097/pai.0000000000000900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/24/2020] [Indexed: 11/26/2022]
Abstract
Breast cancer is a heterogeneous disease at morphologic and molecular levels, which is considered the most commonly occurring cancer in women. RAD51, a DNA-repairing protein, involves homologous recombination and has a vital role in genome stability. Polymorphism of the RAD51 gene, and its overexpression, has been proposed to be associated with the development of breast cancer. Overexpression of RAD51 in many types of human cancer including metastatic breast cancer may signify its potential use as a biomarker. Considering the numerous reports on the role of the 5'-UTR-RAD51 polymorphism in breast cancer, this study aimed to investigate the utility of RAD51 gene expression and its variants G135C and G172T as a possible foretelling factor of breast cancer development. DNA sequencing and immunohistochemistry of RAD51 were conducted on 103 samples from patients diagnosed with sporadic breast cancer and 80 samples from a control group. The results demonstrated that the RAD51 variants, G135C and G172T, were significantly presented in the breast cancer tissue compared with the control group. RAD51 expression was mainly shown in the cytoplasm of malignant cells (56% of cases) and significantly correlated with p53 and G135C, C135C variants. Moreover, the occurrence of the G172T variant was significantly associated with the expression of estrogen receptor. Interestingly, 21/26 (81%) of the triple-negative breast cancer showed G135C and C135C genotypes that were significantly associated with the expression of RAD51 (73%). In conclusion, the G135C and C135C variants together with the cytoplasmic expression of RAD51 may have clinical potential as a prognostic predictor for breast cancer development and aggressiveness.
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The dichotomous effects of caffeine on homologous recombination in mammalian cells. DNA Repair (Amst) 2020; 88:102805. [PMID: 32062581 DOI: 10.1016/j.dnarep.2020.102805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 01/15/2020] [Accepted: 01/19/2020] [Indexed: 11/23/2022]
Abstract
This study was initiated to examine the effects of caffeine on the DNA damage response (DDR) and homologous recombination (HR) in mammalian cells. A 5 mM caffeine treatment caused the cell cycle to stall at G2/M and cells eventually underwent apoptosis. Caffeine exposure also induced a strong DDR along with subsequent activation of wildtype p53 protein. An unexpected observation was the caffeine-induced depletion of Rad51 (and Brca2) proteins. Consequently, caffeine-treated cells were expected to be inefficient in HR. However, a dichotomy in the HR response of cells to caffeine treatment was revealed. Caffeine treatment rendered cells significantly better at performing the nascent DNA synthesis that accompanies the early strand invasion steps of HR. Additionally, caffeine treatment increased chromatin accessibility and elevated the efficiency of illegitimate recombination. Conversely, the increase in nascent DNA synthesis did not translate into a higher number of gene targeting events. Thus, prolonged caffeine exposure stalls the cell cycle, induces a p53-mediated apoptotic response and a down-regulation of critical HR proteins, and for reasons discussed, stimulates early steps of HR, but not the formation of complete recombination products.
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5
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Role of Rad51 and DNA repair in cancer: A molecular perspective. Pharmacol Ther 2020; 208:107492. [PMID: 32001312 DOI: 10.1016/j.pharmthera.2020.107492] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/13/2020] [Accepted: 01/22/2020] [Indexed: 12/24/2022]
Abstract
The maintenance of genome integrity is essential for any organism survival and for the inheritance of traits to offspring. To the purpose, cells have developed a complex DNA repair system to defend the genetic information against both endogenous and exogenous sources of damage. Accordingly, multiple repair pathways can be aroused from the diverse forms of DNA lesions, which can be effective per se or via crosstalk with others to complete the whole DNA repair process. Deficiencies in DNA healing resulting in faulty repair and/or prolonged DNA damage can lead to genes mutations, chromosome rearrangements, genomic instability, and finally carcinogenesis and/or cancer progression. Although it might seem paradoxical, at the same time such defects in DNA repair pathways may have therapeutic implications for potential clinical practice. Here we provide an overview of the main DNA repair pathways, with special focus on the role played by homologous repair and the RAD51 recombinase protein in the cellular DNA damage response. We next discuss the recombinase structure and function per se and in combination with all its principal mediators and regulators. Finally, we conclude with an analysis of the manifold roles that RAD51 plays in carcinogenesis, cancer progression and anticancer drug resistance, and conclude this work with a survey of the most promising therapeutic strategies aimed at targeting RAD51 in experimental oncology.
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Gaynor AS, Chen W. Induced prodrug activation by conditional protein degradation. J Biotechnol 2017; 260:62-66. [PMID: 28912080 PMCID: PMC6595225 DOI: 10.1016/j.jbiotec.2017.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/24/2017] [Accepted: 09/10/2017] [Indexed: 11/17/2022]
Abstract
Enzyme prodrug therapies hold potential as a targeted treatment option for cancer patients. However, off-target effects can be detrimental to patient health and represent a safety concern. This concern can be alleviated by including a failsafe mechanism that can abort the therapy in healthy cells. This feature can be included in enzyme prodrug therapies by use of conditional degradation tags, which degrade the protein unless stabilized. We call this process Degradation-Directed Enzyme Prodrug Therapy (DDEPT). Herein, we use traceless shielding (TShld), a mechanism that degrades a protein of interest unless it is rescued by the addition of rapamycin, to test this concept. We demonstrated that TShld rapidly yielded only native protein products within 1h after rapamycin addition. The rapid protection phenotype of TShld was further adapted to rescue yeast cytosine deaminase, a prodrug converting enzyme. As expected, cell viability was adversely affected only in the presence of both 5-fluorocytosine (5-FC) and rapamycin. We believe that the DDEPT system can be easily combined with other targeting strategies to further increase the safety of prodrug therapies.
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Affiliation(s)
- Andrew S Gaynor
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, USA
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, USA.
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Abstract
The cells in the human body are continuously challenged by a variety of genotoxic attacks. Erroneous repair of the DNA can lead to mutations and chromosomal aberrations that can alter the functions of tumor suppressor genes or oncogenes, thus causing cancer development. As a central tumor suppressor, p53 guards the genome by orchestrating a variety of DNA-damage-response (DDR) mechanisms. Already early in metazoan evolution, p53 started controlling the apoptotic demise of genomically compromised cells. p53 plays a prominent role as a facilitator of DNA repair by halting the cell cycle to allow time for the repair machineries to restore genome stability. In addition, p53 took on diverse roles to also directly impact the activity of various DNA-repair systems. It thus appears as if p53 is multitasking in providing protection from cancer development by maintaining genome stability.
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Affiliation(s)
- Ashley B Williams
- Medical Faculty, Institute for Genome Stability in Ageing and Disease, University of Cologne, 50931 Cologne, Germany Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC) and Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany
| | - Björn Schumacher
- Medical Faculty, Institute for Genome Stability in Ageing and Disease, University of Cologne, 50931 Cologne, Germany Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC) and Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany
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Jeong YK, Kim MS, Lee JY, Kim EH, Ha H. Metformin Radiosensitizes p53-Deficient Colorectal Cancer Cells through Induction of G2/M Arrest and Inhibition of DNA Repair Proteins. PLoS One 2015; 10:e0143596. [PMID: 26599019 PMCID: PMC4657889 DOI: 10.1371/journal.pone.0143596] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 11/06/2015] [Indexed: 12/17/2022] Open
Abstract
The present study addressed whether the combination of metformin and ionizing radiation (IR) would show enhanced antitumor effects in radioresistant p53-deficient colorectal cancer cells, focusing on repair pathways for IR-induced DNA damage. Metformin caused a higher reduction in clonogenic survival as well as greater radiosensitization and inhibition of tumor growth of p53-/- than of p53+/+ colorectal cancer cells and xenografts. Metformin combined with IR induced accumulation of tumor cells in the G2/M phase and delayed the repair of IR-induced DNA damage. In addition, this combination significantly decreased levels of p53-related homologous recombination (HR) repair compared with IR alone, especially in p53-/- colorectal cancer cells and tumors. In conclusion, metformin enhanced radiosensitivity by inducing G2/M arrest and reducing the expression of DNA repair proteins even in radioresistant HCT116 p53-/- colorectal cancer cells and tumors. Our study provides a scientific rationale for the clinical use of metformin as a radiosensitizer in patients with p53-deficient colorectal tumors, which are often resistant to radiotherapy.
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Affiliation(s)
- Youn Kyoung Jeong
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, South Korea
- Research Center for Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Mi-Sook Kim
- Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
- * E-mail: (HH); (MSK)
| | - Ji Young Lee
- Research Center for Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Eun Ho Kim
- Division of Heavy Ion Clinical Research, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Hunjoo Ha
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, South Korea
- * E-mail: (HH); (MSK)
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Mucha B, Kabzinski J, Dziki A, Przybylowska-Sygut K, Sygut A, Majsterek I, Dziki L. Polymorphism within the distal RAD51 gene promoter is associated with colorectal cancer in a Polish population. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:11601-11607. [PMID: 26617897 PMCID: PMC4637713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/21/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Colorectal cancer (CRC) is one of the most common cancers in developed countries. Annually, over one million of new cases in the world are recorded. Majority of CRCs occur sporadically with dominant phenotype of chromosomal instability (CIN). Permanent exposure to DNA damaging agents such as ionizing radiation result in DNA double-stranded breaks, which create favorable conditions for chromosomal aberration to arise. Homologous recombination repair (HRR) is the leading process engaged in maintaining of the genome integrity. RAD51 protein was recognized as crucial in HRR. Single nucleotide polymorphisms are the primary source of genetic variation which presence in the RAD51 promoter region can affect on its expression and consequently modulate HR efficiency. OBJECTIVES The aim of this study was to analyze the distribution of genotypes and allele frequencies of -4791A/T and -4601A/G RAD51 gene polymorphisms, followed by an assessment of their relationship with the risk of CRC. MATERIAL AND METHODS The study included 115 patients with confirmed CRC. Control group was consisted of 118 cancer-free individuals with a negative family history. The genotypes were identified by PCR-RFLP method. CONCLUSION This study revealed statistically significant association between appearance of G/A genotype in position -4601 of RAD51 gene and CRC risk.
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Affiliation(s)
- Bartosz Mucha
- Department of Clinical Chemistry and Biochemistry, Medical University of LodzPoland
| | - Jacek Kabzinski
- Department of Clinical Chemistry and Biochemistry, Medical University of LodzPoland
| | - Adam Dziki
- Department of General and Colorectal Surgery Medical University in LodzPoland
| | | | - Andrzej Sygut
- Department of General and Vascular Surgery, Medical Center of PabianicePoland
| | - Ireneusz Majsterek
- Department of Clinical Chemistry and Biochemistry, Medical University of LodzPoland
| | - Lukasz Dziki
- Department of General and Colorectal Surgery Medical University in LodzPoland
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Cao Y, Xu Y, Zhang L, Li Z, Jiang Y, Tian X, Seluanov A, Gorbunova V, Mao Z. Utilization of Rad51C promoter for transcriptional targeting of cancer cells. Oncotarget 2015; 5:1805-11. [PMID: 24742710 PMCID: PMC4039114 DOI: 10.18632/oncotarget.1792] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cancer therapy that specifically targets malignant cells with minimal or no toxicity to normal tissue has been a long-standing goal of cancer research. Rad51 expression is elevated in a wide range of cancers and Rad51 promoter has been used to transcriptionally target tumor cells, however, a large size of Rad51 promoter limits its application for gene therapy. To identify novel tumor-specific promoters, we examined expression levels of Rad51 paralogs, Rad51B, Rad51C, and Rad51D as well as Rad52 in a panel of normal and tumor cell lines. We found that Rad51C is significantly overexpressed in cancer cells. The expression was up-regulated by approximately 6-fold at the mRNA level and 9-fold at the protein level. Interestingly, the 2064 bp long Rad51C promoter fragment was approximately 300-fold higher in cancer cells than in normal cells. A construct containing Rad51C promoter driving diphtheria toxin A efficiently killed several types of cancer cells with very mild effect to normal cells. These results underscore the potential of targeting the homologous recombination pathway in cancer cells and provide a proof of principle that the Rad51C promoter fragment can be used to transcriptionally target cancer cells.
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Affiliation(s)
- Yan Cao
- School of Life Sciences and Technology, Tongji University, Shanghai, China
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Zhang J. Poly (ADP-ribose) polymerase inhibitor: an evolving paradigm in the treatment of prostate cancer. Asian J Androl 2014; 16:401-6. [PMID: 24589464 PMCID: PMC4023365 DOI: 10.4103/1008-682x.123684] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Recent phase I studies have reported single-agent activities of poly (ADP-ribose) polymerase (PARP) inhibitor in sporadic and in BRCA-mutant prostate cancers. Two of the most common genetic alterations in prostate cancer, ETS gene rearrangement and loss of PTEN, have been linked to increased sensitivity to PARP inhibitor in preclinical models. Emerging evidence also suggests that PARP1 plays an important role in mediating the transcriptional activities of androgen receptor (AR) and ETS gene rearrangement. In this article, the preclinical work and early-phase clinical trials in developing PARP inhibitor-based therapy as a new treatment paradigm for metastatic prostate cancer are reviewed.
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Affiliation(s)
- Jingsong Zhang
- Department of Genitourinary Oncology and Department of Cancer Imaging and Metabolism, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
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Hine CM, Li H, Xie L, Mao Z, Seluanov A, Gorbunova V. Regulation of Rad51 promoter. Cell Cycle 2014; 13:2038-45. [PMID: 24781030 DOI: 10.4161/cc.29016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The DNA double-strand break repair and homologous recombination protein Rad51 is overexpressed in the majority of human cancers. This correlates with therapy resistance and decreased patient survival. We previously showed that constructs containing Rad51 promoter fused to a reporter gene are, on average, 850-fold more active in cancer cells than in normal cells. It is not well understood what factors and sequences regulate the Rad51 promoter and cause its high activity in cancerous cells. Here we characterized regulatory regions and examined genetic requirements for oncogenic stimulation of the Rad51 promoter. We identified specific regions responsible for up- and downregulation of the Rad51 promoter in cancerous cells. Furthermore, we show that Rad51 expression is positively regulated by EGR1 transcription factor. We then modeled the malignant transformation process by expressing a set of oncoproteins in normal human fibroblasts. Expression of different combinations of SV40 large T antigen, oncogenic Ras and SV40 small T antigen resulted in step-wise increase in Rad51 promoter activity, with all the 3 oncoproteins together leading to a 47-fold increase in expression. Cumulatively, these results suggest that Rad51 promoter is regulated by multiple factors, and that its expression is gradually activated as cells progress toward malignancy.
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Affiliation(s)
| | - Hongjie Li
- Department of Biology; University of Rochester; Rochester, NY USA
| | - Li Xie
- Department of Biology; University of Rochester; Rochester, NY USA
| | - Zhiyong Mao
- Department of Biology; University of Rochester; Rochester, NY USA
| | - Andrei Seluanov
- Department of Biology; University of Rochester; Rochester, NY USA
| | - Vera Gorbunova
- Department of Biology; University of Rochester; Rochester, NY USA
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Giantin M, Granato A, Baratto C, Marconato L, Vascellari M, Morello EM, Vercelli A, Mutinelli F, Dacasto M. Global gene expression analysis of canine cutaneous mast cell tumor: could molecular profiling be useful for subtype classification and prognostication? PLoS One 2014; 9:e95481. [PMID: 24748173 PMCID: PMC3991658 DOI: 10.1371/journal.pone.0095481] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 03/27/2014] [Indexed: 02/06/2023] Open
Abstract
Prognosis and therapeutic management of dogs with cutaneous mast cell tumors (MCTs) depend on clinical stage and histological grade. However, the prognostic value of this latter is still questionable. In the present study, MCT transcriptome was analyzed to identify a set of candidate genes potentially useful for predicting the biological behavior of MCTs. Fifty-one canine MCT biopsies were analyzed. Isolated and purified total RNAs were individually hybridized to the Agilent Canine V2 4x44k DNA microarray. The comparison of reference differentiated and undifferentiated MCT transcriptome revealed a total of 597 differentially expressed genes (147 down-regulated and 450 up-regulated). The functional analysis of this set of genes provided evidence that they were mainly involved in cell cycle, DNA replication, p53 signaling pathway, nucleotide excision repair and pyrimidine metabolism. Class prediction analysis identified 13 transcripts providing the greatest accuracy of class prediction and divided samples into two categories (differentiated and undifferentiated), harboring a different prognosis. The Principal Component Analysis of all samples, made by using the selected 13 markers, confirmed MCT classification. The first three components accounted for 99.924% of the total variance. This molecular classification significantly correlated with survival time (p = 0.0026). Furthermore, among all marker genes, a significant association was found between mRNA expression and MCT-related mortality for FOXM1, GSN, FEN1 and KPNA2 (p<0.05). Finally, marker genes mRNA expression was evaluated in a cohort of 22 independent samples. Data obtained enabled to identify MCT cases with different prognosis. Overall, the molecular characterization of canine MCT transcriptome allowed the identification of a set of 13 transcripts that clearly separated differentiated from undifferentiated MCTs, thus predicting outcome regardless of the histological grade. These results may have clinical relevance and warrant future validation in a prospective study.
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Affiliation(s)
- Mery Giantin
- Dipartimento di Biomedicina Comparata e Alimentazione, Università di Padova, Legnaro (Padova), Italy
- * E-mail:
| | - Anna Granato
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (Padova), Italy
| | - Chiara Baratto
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (Padova), Italy
| | - Laura Marconato
- Centro Oncologico Veterinario, Sasso Marconi, Bologna, Italy
| | - Marta Vascellari
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (Padova), Italy
| | - Emanuela M. Morello
- Dipartimento di Scienze Veterinarie, Università di Torino, Grugliasco (Torino), Italy
| | | | - Franco Mutinelli
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (Padova), Italy
| | - Mauro Dacasto
- Dipartimento di Biomedicina Comparata e Alimentazione, Università di Padova, Legnaro (Padova), Italy
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Carvalho JFS, Kanaar R. Targeting homologous recombination-mediated DNA repair in cancer. Expert Opin Ther Targets 2014; 18:427-58. [PMID: 24491188 DOI: 10.1517/14728222.2014.882900] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION DNA is the target of many traditional non-specific chemotherapeutic drugs. New drugs or therapeutic approaches with a more rational and targeted component are mandatory to improve the success of cancer therapy. The homologous recombination (HR) pathway is an attractive target for the development of inhibitors because cancer cells rely heavily on HR for repair of DNA double-strand breaks resulting from chemotherapeutic treatments. Additionally, the discovery that poly(ADP)ribose polymerase-1 inhibitors selectively kill cells with genetic defects in HR has spurned an even greater interest in inhibitors of HR. AREAS COVERED HR drives the repair of broken DNA via numerous protein-mediated sequential DNA manipulations. Due to extensive number of steps and proteins involved, the HR pathway provides a rich pool of potential drug targets. This review discusses the latest developments concerning the strategies being explored to inhibit HR. Particular attention is given to the identification of small molecule inhibitors of key HR proteins, including the BRCA proteins and RAD51. EXPERT OPINION Current HR inhibitors are providing the basis for pharmaceutical development of more potent and specific inhibitors to be applied in mono- or combinatorial therapy regimes, while novel targets will be uncovered by experiments aimed to gain a deeper mechanistic understanding of HR and its subpathways.
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Affiliation(s)
- João F S Carvalho
- Erasmus MC Cancer Institute, Department of Genetics, Department of Radiation Oncology, Cancer Genomics Netherlands , PO Box 2040, 3000 CA Rotterdam , The Netherlands
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