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Engin AB, Engin A. DNA damage checkpoint response to aflatoxin B1. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2019; 65:90-96. [PMID: 30594067 DOI: 10.1016/j.etap.2018.12.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 11/20/2018] [Accepted: 12/07/2018] [Indexed: 05/28/2023]
Abstract
Although most countries regulate the aflatoxin levels in food by legislations, high amounts of aflatoxin B1 (AFB1)-DNA adducts can still be detected in normal and tumorous tissue obtained from cancer patients. AFB1 cannot directly interact with DNA unless it is biotransformed to AFB1-8, 9-epoxide via cytochrome p450 enzymes. This metabolite spontaneously and irreversibly attaches to guanine residues to generate highly mutagenic DNA adducts. AFB1-induced mutation of ATM kinase results in the deterioration of the cell cycle checkpoint activation at the G2/M checkpoint site. Genomic instability and increased cancer risk due to A-T mutation is the result of diminished repair of DNA double strand breaks. The major point mutation caused by AFB1 is G-to-T transversion that is related with the high frequency of p53 mutation. Majority of AFB1 associated hepatocellular cancer cases carry TP53 mutant DNA, which is an indicator of AFB1 exposure, as well as hepatocellular cancer risk.
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Affiliation(s)
- Ayse Basak Engin
- Gazi University, Faculty of Pharmacy, Department of Toxicology, Ankara, Turkey.
| | - Atilla Engin
- Gazi University, Faculty of Medicine, Department of General Surgery, Ankara, Turkey
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Wang YJ, Li Q, Xiao HB, Li YJ, Yang Q, Kan XX, Chen Y, Liu XN, Weng XG, Chen X, Cai WY, Guo Y, Huang HF, Zhu XX. Chamaejasmin B exerts anti-MDR effect in vitro and in vivo via initiating mitochondria-dependant intrinsic apoptosis pathway. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:5301-13. [PMID: 26445529 PMCID: PMC4590417 DOI: 10.2147/dddt.s89392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Multidrug resistance (MDR) is the main obstacle limiting the efficacy of cancer chemotherapy. Looking for novel anti-MDR agents is an important way to conquer cancer drug resistance. We recently established that chamaejasmin B (CHB), a natural biflavone from Stellera chamaejasme L., is the major active component. However, its anti-MDR activity is still unknown. This study investigated the anti-MDR effect of CHB and the underlying mechanisms. First, it was found that CHB inhibited the growth of both sensitive and resistant cell lines in vitro, and the average resistant factor (RF) of CHB was only 1.26. Furthermore, CHB also displayed favorable anti-MDR activity in KB and KBV200 cancer cells xenograft mice. Subsequent study showed that CHB induced G0/G1 cell cycle arrest as well as apoptosis both in KB and in resistant KBV200 cancer cells. Further studies showed that CHB had no influence on the level of Fas/FasL and activation of procaspase 8. However, CHB-induced apoptosis was dependent on the activation of caspase 9 and caspase 3. Moreover, CHB treatment resulted in the elevation of the Bax/Bcl-2 ratio, attenuation of mitochondrial membrane potential (ΔΨm), and release of cytochrome c and apoptosis-inducing factor from mitochondria into cytoplasm both in KB and KBV200 cells. In conclusion, CHB exhibited good anti-MDR activity in vitro and in vivo, and the underlying mechanisms may be related to the activation of mitochondrial-dependant intrinsic apoptosis pathway. These findings provide a new leading compound for MDR therapy and supply a new evidence for the potential of CHB to be employed in clinical trial of MDR therapy in cancers.
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Affiliation(s)
- Ya Jie Wang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Qi Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Hong Bin Xiao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Yu Jie Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Qing Yang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Xiao Xi Kan
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Xiao Ni Liu
- Beijing Institute of Hepatology and Beijing Youan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xiao Gang Weng
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Xi Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Wei Yan Cai
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Yan Guo
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - He Fei Huang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Xiao Xin Zhu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Capital Medical University, Beijing, People's Republic of China
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Involvement of DNA damage response pathways in hepatocellular carcinoma. BIOMED RESEARCH INTERNATIONAL 2014; 2014:153867. [PMID: 24877058 PMCID: PMC4022277 DOI: 10.1155/2014/153867] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/23/2014] [Accepted: 03/25/2014] [Indexed: 12/16/2022]
Abstract
Hepatocellular carcinoma (HCC) has been known as one of the most lethal human malignancies, due to the difficulty of early detection, chemoresistance, and radioresistance, and is characterized by active angiogenesis and metastasis, which account for rapid recurrence and poor survival. Its development has been closely associated with multiple risk factors, including hepatitis B and C virus infection, alcohol consumption, obesity, and diet contamination. Genetic alterations and genomic instability, probably resulted from unrepaired DNA lesions, are increasingly recognized as a common feature of human HCC. Dysregulation of DNA damage repair and signaling to cell cycle checkpoints, known as the DNA damage response (DDR), is associated with a predisposition to cancer and affects responses to DNA-damaging anticancer therapy. It has been demonstrated that various HCC-associated risk factors are able to promote DNA damages, formation of DNA adducts, and chromosomal aberrations. Hence, alterations in the DDR pathways may accumulate these lesions to trigger hepatocarcinogenesis and also to facilitate advanced HCC progression. This review collects some of the most known information about the link between HCC-associated risk factors and DDR pathways in HCC. Hopefully, the review will remind the researchers and clinicians of further characterizing and validating the roles of these DDR pathways in HCC.
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Cui J, Liu J, Wu S, Wang Y, Shen H, Xing L, Wang J, Yan X, Zhang X. Oxidative DNA damage is involved in ochratoxin A-induced G2 arrest through ataxia telangiectasia-mutated (ATM) pathways in human gastric epithelium GES-1 cells in vitro. Arch Toxicol 2013; 87:1829-40. [PMID: 23515941 DOI: 10.1007/s00204-013-1043-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/08/2013] [Indexed: 01/17/2023]
Abstract
Ochratoxin A (OTA), one of the most abundant mycotoxin food contaminants, is classified as "possibly carcinogenic to humans." Our previous study showed that OTA could induce a G2 arrest in immortalized human gastric epithelium cells (GES-1). To explore the putative roles of oxidative DNA damage and the ataxia telangiectasia-mutated (ATM) pathways on the OTA-induced G2 arrest, the current study systematically evaluated the roles of reactive oxygen species (ROS) production, DNA damage, and ATM-dependent pathway activation on the OTA-induced G2 phase arrest in GES-1 cells. The results showed that OTA exposure elevated intracellular ROS production, which directly induced DNA damage and increased the levels of 8-OHdG and DNA double-strand breaks (DSBs). In addition, it was found that OTA treatment induced the phosphorylation of the ATM protein, as well as its downstream molecules Chk2 and p53, in response to DNA DSBs. Inhibition of ATM by the pharmacological inhibitor caffeine or siRNA effectively prevented the activation of ATM-dependent pathways and rescued the G2 arrest elicited by OTA. Finally, pretreatment with the antioxidant N-acetyl-L-cysteine (NAC) reduced the OTA-induced DNA DSBs, ATM phosphorylation, and G2 arrest. In conclusion, the results of this study suggested that OTA-induced oxidative DNA damage triggered the ATM-dependent pathways, which ultimately elicited a G2 arrest in GES-1 cells.
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Affiliation(s)
- Jinfeng Cui
- Department of Pathology, The Second Hospital, Hebei Medical University, No. 215, Heping Western Road, Shijiazhuang, Hebei, People's Republic of China
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