1
|
Munera López J, Ganuza A, Bogado SS, Muñoz D, Ruiz DM, Sullivan WJ, Vanagas L, Angel SO. Evaluation of ATM Kinase Inhibitor KU-55933 as Potential Anti- Toxoplasma gondii Agent. Front Cell Infect Microbiol 2019; 9:26. [PMID: 30815397 PMCID: PMC6381018 DOI: 10.3389/fcimb.2019.00026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/25/2019] [Indexed: 01/01/2023] Open
Abstract
Toxoplasma gondii is an apicomplexan protozoan parasite with a complex life cycle composed of multiple stages that infect mammals and birds. Tachyzoites rapidly replicate within host cells to produce acute infection during which the parasite disseminates to tissues and organs. Highly replicative cells are subject to Double Strand Breaks (DSBs) by replication fork collapse and ATM, a member of the phosphatidylinositol 3-kinase (PI3K) family, is a key factor that initiates DNA repair and activates cell cycle checkpoints. Here we demonstrate that the treatment of intracellular tachyzoites with the PI3K inhibitor caffeine or ATM kinase-inhibitor KU-55933 affects parasite replication rate in a dose-dependent manner. KU-55933 affects intracellular tachyzoite growth and induces G1-phase arrest. Addition of KU-55933 to extracellular tachyzoites also leads to a significant reduction of tachyzoite replication upon infection of host cells. ATM kinase phosphorylates H2A.X (γH2AX) to promote DSB damage repair. The level of γH2AX increases in tachyzoites treated with camptothecin (CPT), a drug that generates fork collapse, but this increase was not observed when co-administered with KU-55933. These findings support that KU-55933 is affecting the Toxoplasma ATM-like kinase (TgATM). The combination of KU-55933 and other DNA damaging agents such as methyl methane sulfonate (MMS) and CPT produce a synergic effect, suggesting that TgATM kinase inhibition sensitizes the parasite to damaged DNA. By contrast, hydroxyurea (HU) did not further inhibit tachyzoite replication when combined with KU-55933.
Collapse
Affiliation(s)
- Jonathan Munera López
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Agustina Ganuza
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Silvina S Bogado
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Daniela Muñoz
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Diego M Ruiz
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - William J Sullivan
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States.,Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Laura Vanagas
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Sergio O Angel
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| |
Collapse
|
2
|
Ren X, Tang Y, Sun J, Feng J, Chen L, Chen H, Zeng S, Chen C, Li X, Zhu H, Zeng Z. Flavone protects HBE cells from DNA double-strand breaks caused by PM2.5. Hum Cell 2017; 31:116-126. [PMID: 29168129 DOI: 10.1007/s13577-017-0193-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/06/2017] [Indexed: 12/29/2022]
Abstract
Ambient air particulate matter 2.5 (PM2.5) contains many harmful components that can enter the circulatory system and produce reactive oxygen species (ROS) in body. Oxidative stress and DNA damage induced by ROS may affect any cellular macromolecule and lead to DNA double-strand breaks (DSBs). Flavonoids, widely distributed in some herbs and berries, have been proved having anti-oxidative or anti-cancer efficacy. In this study, we investigated whether Flavone, a kind of flavonoids, can protect human bronchial epithelial cells (HBE) from DSBs caused by PM2.5 and how this function is probably implemented. We found that cells exposed to PM2.5 obviously induced viability inhibition, DNA damage and part of apoptosis. However, Flavone treatment prior to PM2.5 apparently improved cell viability, and mitigated the formation of 8-hydroxy-2-deoxyguanosine, the expression of DNA damage-relative protein and cell apoptosis. Our studies demonstrated that PM2.5 induced oxidative DSBs while Flavone ameliorated the DNA damage and increased cell viability probably through influencing DNA repair mechanism of cells.
Collapse
Affiliation(s)
- Xing Ren
- School of Life Sciences, Central South University, Xiangya Road No. 110, Changsha, 410078, Hunan, People's Republic of China
| | - Yong Tang
- School of Life Sciences, Central South University, Xiangya Road No. 110, Changsha, 410078, Hunan, People's Republic of China
| | - Jiameng Sun
- School of Life Sciences, Central South University, Xiangya Road No. 110, Changsha, 410078, Hunan, People's Republic of China
| | - Jianbo Feng
- Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, 410078, People's Republic of China
| | - Leilei Chen
- Xiangya School of Medicine, Central South University, Changsha, 410078, People's Republic of China
| | - Huixi Chen
- Xiangya School of Medicine, Central South University, Changsha, 410078, People's Republic of China
| | - Sijing Zeng
- School of Life Sciences, Central South University, Xiangya Road No. 110, Changsha, 410078, Hunan, People's Republic of China
| | - Changhui Chen
- School of Life Sciences, Central South University, Xiangya Road No. 110, Changsha, 410078, Hunan, People's Republic of China
| | - Xinqiu Li
- Xiangya School of Medicine, Central South University, Changsha, 410078, People's Republic of China
| | - Haixia Zhu
- The Third Hospital of Xiangya, Central South University, Tongzipo Road No. 138, Changsha, 410013, Hunan, People's Republic of China
| | - Zhaojun Zeng
- School of Life Sciences, Central South University, Xiangya Road No. 110, Changsha, 410078, Hunan, People's Republic of China. .,State Key Laboratory of Medical Genetics, Central South University, Changsha, People's Republic of China.
| |
Collapse
|
3
|
Allam WR, Ashour ME, Waly AA, El-Khamisy S. Role of Protein Linked DNA Breaks in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1007:41-58. [PMID: 28840551 DOI: 10.1007/978-3-319-60733-7_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Topoisomerases are a group of specialized enzymes that function to maintain DNA topology by introducing transient DNA breaks during transcription and replication. As a result of abortive topoisomerases activity, topoisomerases catalytic intermediates may be trapped on the DNA forming topoisomerase cleavage complexes (Topcc). Topoisomerases trapping on the DNA is the mode of action of several anticancer drugs, it lead to formation of protein linked DAN breaks (PDBs). PDBs are now considered as one of the most dangerous forms of endogenous DNA damage and a major threat to genomic stability. The repair of PDBs involves both the sensing and repair pathways. Unsuccessful repair of PDBs leads to different signs of genomic instabilities such as chromosomal rearrangements and cancer predisposition. In this chapter we will summarize the role of topoisomerases induced PDBs, identification and signaling, repair, role in transcription. We will also discuss the role of PDBs in cancer with a special focus on prostate cancer.
Collapse
Affiliation(s)
- Walaa R Allam
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt.
| | - Mohamed E Ashour
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
| | - Amr A Waly
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
| | - Sherif El-Khamisy
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt. .,Krebs Institute and Sheffield Institute for Nucleic Acids, Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Sheffield, S10 2TN, UK.
| |
Collapse
|
4
|
Rodemann HP, Bodis S. Cutting-edge research in basic and translational radiation biology/oncology reflections from the 14th International Wolfsberg Meeting on Molecular Radiation Biology/Oncology 2015. Radiother Oncol 2015; 116:335-41. [DOI: 10.1016/j.radonc.2015.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 09/04/2015] [Accepted: 09/05/2015] [Indexed: 01/11/2023]
|
5
|
Plimack ER, Dunbrack RL, Brennan TA, Andrake MD, Zhou Y, Serebriiskii IG, Slifker M, Alpaugh K, Dulaimi E, Palma N, Hoffman-Censits J, Bilusic M, Wong YN, Kutikov A, Viterbo R, Greenberg RE, Chen DYT, Lallas CD, Trabulsi EJ, Yelensky R, McConkey DJ, Miller VA, Golemis EA, Ross EA. Defects in DNA Repair Genes Predict Response to Neoadjuvant Cisplatin-based Chemotherapy in Muscle-invasive Bladder Cancer. Eur Urol 2015; 68:959-67. [PMID: 26238431 DOI: 10.1016/j.eururo.2015.07.009] [Citation(s) in RCA: 359] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/03/2015] [Indexed: 01/18/2023]
Abstract
BACKGROUND Cisplatin-based neoadjuvant chemotherapy (NAC) before cystectomy is the standard of care for muscle-invasive bladder cancer (MIBC), with 25-50% of patients expected to achieve a pathologic response. Validated biomarkers predictive of response are currently lacking. OBJECTIVE To discover and validate biomarkers predictive of response to NAC for MIBC. DESIGN, SETTING, AND PARTICIPANTS Pretreatment MIBC samples prospectively collected from patients treated in two separate clinical trials of cisplatin-based NAC provided the discovery and validation sets. DNA from pretreatment tumor tissue was sequenced for all coding exons of 287 cancer-related genes and was analyzed for base substitutions, indels, copy number alterations, and selected rearrangements in a Clinical Laboratory Improvements Amendments-certified laboratory. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The mean number of variants and variant status for each gene were correlated with response. Variant data from the discovery cohort were used to create a classification tree to discriminate responders from nonresponders. The resulting decision rule was then tested in the independent validation set. RESULTS AND LIMITATIONS Patients with a pathologic complete response had more alterations than those with residual tumor in both the discovery (p=0.024) and validation (p=0.018) sets. In the discovery set, alteration in one or more of the three DNA repair genes ATM, RB1, and FANCC predicted pathologic response (p<0.001; 87% sensitivity, 100% specificity) and better overall survival (p=0.007). This test remained predictive for pathologic response in the validation set (p=0.033), with a trend towards better overall survival (p=0.055). These results require further validation in additional sample sets. CONCLUSIONS Genomic alterations in the DNA repair-associated genes ATM, RB1, and FANCC predict response and clinical benefit after cisplatin-based chemotherapy for MIBC. The results suggest that defective DNA repair renders tumors sensitive to cisplatin. PATIENT SUMMARY Chemotherapy given before bladder removal (cystectomy) improves the chance of cure for some but not all patients with muscle-invasive bladder cancer. We found a set of genetic mutations that when present in tumor tissue predict benefit from neoadjuvant chemotherapy, suggesting that testing before chemotherapy may help in selecting patients for whom this approach is recommended.
Collapse
Affiliation(s)
| | | | | | | | - Yan Zhou
- Fox Chase Cancer Center, Philadelphia, PA, USA
| | | | | | | | | | - Norma Palma
- Foundation Medicine Inc., Cambridge, MA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Eric A Ross
- Fox Chase Cancer Center, Philadelphia, PA, USA
| |
Collapse
|
6
|
Wu CC, Huang KF, Yang TY, Li YL, Wen CL, Hsu SL, Chen TH. The Topoisomerase 1 Inhibitor Austrobailignan-1 Isolated from Koelreuteria henryi Induces a G2/M-Phase Arrest and Cell Death Independently of p53 in Non-Small Cell Lung Cancer Cells. PLoS One 2015; 10:e0132052. [PMID: 26147394 PMCID: PMC4492957 DOI: 10.1371/journal.pone.0132052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 06/09/2015] [Indexed: 11/18/2022] Open
Abstract
Koelreuteria henryi Dummer, an endemic plant of Taiwan, has been used as a folk medicine for the treatment of hepatitis, enteritis, cough, pharyngitis, allergy, hypertension, hyperlipidemia, and cancer. Austrobailignan-1, a natural lignan derivative isolated from Koelreuteria henryi Dummer, has anti-oxidative and anti-cancer properties. However, the effects of austrobailignan-1 on human cancer cells have not been studied yet. Here, we showed that austrobailignan-1 inhibited cell growth of human non-small cell lung cancer A549 and H1299 cell lines in both dose- and time-dependent manners, the IC50 value (48 h) of austrobailignan-1 were 41 and 22 nM, respectively. Data from flow cytometric analysis indicated that treatment with austrobailignan-1 for 24 h retarded the cell cycle at the G2/M phase. The molecular event of austrobailignan-1-mediated G2/M phase arrest was associated with the increase of p21Waf1/Cip1 and p27Kip1 expression, and decrease of Cdc25C expression. Moreover, treatment with 100 nM austrobailignan-1 for 48 h resulted in a pronounced release of cytochrome c followed by the activation of caspase-2, -3, and -9, and consequently induced apoptosis. These events were accompanied by the increase of PUMA and Bax, and the decrease of Mcl-1 and Bcl-2. Furthermore, our study also showed that austrobailignan-1 was a topoisomerase 1 inhibitor, as evidenced by a relaxation assay and induction of a DNA damage response signaling pathway, including ATM, and Chk1, Chk2, γH2AX phosphorylated activation. Overall, our results suggest that austrobailignan-1 is a novel DNA damaging agent and displays a topoisomerase I inhibitory activity, causes DNA strand breaks, and consequently induces DNA damage response signaling for cell cycle G2/M arrest and apoptosis in a p53 independent manner.
Collapse
Affiliation(s)
- Chun-Chi Wu
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, ROC
- Department of Medical Research, Chung-Shan Medical University Hospital, Taichung, Taiwan, ROC
| | - Keh-Feng Huang
- Department of Applied Chemistry, Providence University, Taichung, Taiwan, ROC
| | - Tsung-Ying Yang
- Division of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Ya-Ling Li
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
| | - Chi-Luan Wen
- Taiwan Seed Improvement and Propagation Station, Council of Agriculture, Propagation Technology Section, Taichung, Taiwan, ROC
| | - Shih-Lan Hsu
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
| | - Tzu-Hsiu Chen
- Department of Health and Nutrition, Chia Nan University of Pharmacy & Science, Tainan, Taiwan, ROC
- * E-mail:
| |
Collapse
|
7
|
Bakr A, Oing C, Köcher S, Borgmann K, Dornreiter I, Petersen C, Dikomey E, Mansour WY. Involvement of ATM in homologous recombination after end resection and RAD51 nucleofilament formation. Nucleic Acids Res 2015; 43:3154-66. [PMID: 25753674 PMCID: PMC4381069 DOI: 10.1093/nar/gkv160] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 02/18/2015] [Indexed: 12/03/2022] Open
Abstract
Ataxia-telangiectasia mutated (ATM) is needed for the initiation of the double-strand break (DSB) repair by homologous recombination (HR). ATM triggers DSB end resection by stimulating the nucleolytic activity of CtIP and MRE11 to generate 3′-ssDNA overhangs, followed by RPA loading and RAD51 nucleofilament formation. Here we show for the first time that ATM is also needed for later steps in HR after RAD51 nucleofilament formation. Inhibition of ATM after completion of end resection did not affect RAD51 nucleofilament formation, but resulted in HR deficiency as evidenced by (i) an increase in the number of residual RAD51/γH2AX foci in both S and G2 cells, (ii) the decrease in HR efficiency as detected by HR repair substrate (pGC), (iii) a reduced SCE rate and (iv) the radiosensitization of cells by PARP inhibition. This newly described role for ATM was found to be dispensable in heterochromatin-associated DSB repair, as KAP1-depletion did not alleviate the HR-deficiency when ATM was inhibited after end resection. Moreover, we demonstrated that ATR can partly compensate for the deficiency in early, but not in later, steps of HR upon ATM inhibition. Taken together, we describe here for the first time that ATM is needed not only for the initiation but also for the completion of HR.
Collapse
Affiliation(s)
- A Bakr
- Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - C Oing
- Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany Department of Oncology, Hematology and Bone Marrow Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - S Köcher
- Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - K Borgmann
- Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - I Dornreiter
- Heinrich-Pette-Institute, Leibniz-Institute for Experimental Virology, Hamburg 20251, Germany
| | - C Petersen
- Department of Radiotherapy & Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - E Dikomey
- Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - W Y Mansour
- Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany Tumor Biology Department, National Cancer Institute, Cairo University, Cairo 11796, Egypt
| |
Collapse
|
8
|
Ashour ME, Atteya R, El-Khamisy SF. Topoisomerase-mediated chromosomal break repair: an emerging player in many games. Nat Rev Cancer 2015; 15:137-51. [PMID: 25693836 DOI: 10.1038/nrc3892] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mammalian genome is constantly challenged by exogenous and endogenous threats. Although much is known about the mechanisms that maintain DNA and RNA integrity, we know surprisingly little about the mechanisms that underpin the pathology and tissue specificity of many disorders caused by defective responses to DNA or RNA damage. Of the different types of endogenous damage, protein-linked DNA breaks (PDBs) are emerging as an important player in cancer development and therapy. PDBs can arise during the abortive activity of DNA topoisomerases, a class of enzymes that modulate DNA topology during several chromosomal transactions, such as gene transcription and DNA replication, recombination and repair. In this Review, we discuss the mechanisms underpinning topoisomerase-induced PDB formation and repair with a focus on their role during gene transcription and the development of tissue-specific cancers.
Collapse
Affiliation(s)
- Mohamed E Ashour
- 1] Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK. [2] Center for Genomics, Helmy Institute, Zewail City of Science and Technology, Giza 12588, Egypt
| | - Reham Atteya
- Center for Genomics, Helmy Institute, Zewail City of Science and Technology, Giza 12588, Egypt
| | - Sherif F El-Khamisy
- 1] Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK. [2] Center for Genomics, Helmy Institute, Zewail City of Science and Technology, Giza 12588, Egypt
| |
Collapse
|
9
|
Ling X, Xu C, Fan C, Zhong K, Li F, Wang X. FL118 induces p53-dependent senescence in colorectal cancer cells by promoting degradation of MdmX. Cancer Res 2015; 74:7487-97. [PMID: 25512388 DOI: 10.1158/0008-5472.can-14-0683] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Anticancer agent FL118 was recently identified in screening of small-molecule inhibitors of human survivin expression. Although FL118 is a camptothecin analogue, its antitumor potency is much superior to other FDA-approved camptothecin analogues (irinotecan and topotecan). The mechanism of action (MOA) underlying the antitumor effects of FL118 remains to be fully elucidated. Here, we report that FL118 activates tumor suppressor p53 as a novel MOA in p53 wild-type cancer cells. Our studies show that this MOA involves an induction of proteasomal degradation of MdmX, a critical negative regulator of p53, in a manner largely independent of ATM-dependent DNA damage signaling pathway but dependent on E3-competent Mdm2. FL118 inhibits p53 polyubiquitination and monoubiquitination by Mdm2-MdmX E3 complex in cells and in cell-free systems. In contrast, FL118 stimulates Mdm2-mediated MdmX ubiquitination. Coimmunoprecipitation revealed that FL118 slightly decreases Mdm2-p53 interactions and moderately increases Mdm2-MdmX interactions, suggesting a change of targeting specificity of Mdm2-MdmX E3 complex from p53 to MdmX, resulting in accelerated MdmX degradation. As a result, p53 ubiquitination by Mdm2-MdmX E3 complex is reduced, which in turn activates p53 signaling. Activation of the p53 pathway by FL118 induces p53-dependent senescence in colorectal cancer cells. However, in the absence of p53 or in the presence of MdmX overexpression, FL118 promotes p53-independent apoptosis. These two distinct cellular consequences collectively contribute to the potent effects of FL118 to inhibit clonogenic potential of colon cancer cells. This study identifies a potential application of FL118 as an MdmX inhibitor for targeted therapies.
Collapse
Affiliation(s)
- Xiang Ling
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York. Canget BioTekpharma, LLC, Buffalo, New York
| | - Chao Xu
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York
| | - Chuandong Fan
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York
| | - Kai Zhong
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York
| | - Fengzhi Li
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York.
| | - Xinjiang Wang
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York.
| |
Collapse
|
10
|
Huang F, Mazin AV. A small molecule inhibitor of human RAD51 potentiates breast cancer cell killing by therapeutic agents in mouse xenografts. PLoS One 2014; 9:e100993. [PMID: 24971740 PMCID: PMC4074124 DOI: 10.1371/journal.pone.0100993] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 05/30/2014] [Indexed: 01/06/2023] Open
Abstract
The homologous recombination pathway is responsible for the repair of DNA double strand breaks. RAD51, a key homologous recombination protein, promotes the search for homology and DNA strand exchange between homologous DNA molecules. RAD51 is overexpressed in a variety of cancer cells. Downregulation of RAD51 by siRNA increases radio- or chemo-sensitivity of cancer cells. We recently developed a specific RAD51 small molecule inhibitor, B02, which inhibits DNA strand exchange activity of RAD51 in vitro. In this study, we used human breast cancer cells MDA-MB-231 to investigate the ability of B02 to inhibit RAD51 and to potentiate an anti-cancer effect of chemotherapeutic agents including doxorubicin, etoposide, topotecan, and cisplatin. We found that the combination of B02 with cisplatin has the strongest killing effect on the cancer cells. We then tested the effect of B02 and cisplatin on the MDA-MB-231 cell proliferation in mouse xenografts. Our results showed that B02 significantly enhances the therapeutic effect of cisplatin on tumor cells in vivo. Our current data demonstrate that use of RAD51-specific small molecule inhibitor represents a feasible strategy of a combination anti-cancer therapy.
Collapse
Affiliation(s)
- Fei Huang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Alexander V. Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| |
Collapse
|