title: B5, a thioredoxin reductase inhibitor, induces apoptosis in human cervical cancer cells by suppressing the thioredoxin system, disrupting mitochondrion-dependent pathways and triggering autophagy.
abstract: The synthetic curcumin analog B5 is a potent inhibitor of thioredoxin reductase (TrxR) that has potential anticancer effects. The molecular mechanism underlying B5 as an anticancer agent is not yet fully understood. In this study, we report that B5 induces apoptosis in two human cervical cancer cell lines, CaSki and SiHa, as evidenced by the downregulation of XIAP, activation of caspases and cleavage of PARP. The involvement of the mitochondrial pathway in B5-induced apoptosis was suggested by the dissipation of mitochondrial membrane potential and increased expression of pro-apoptotic Bcl-2 family proteins. In B5-treated cells, TrxR activity was markedly inhibited with concomitant accumulation of oxidized thioredoxin, increased formation of reactive oxygen species (ROS), and activation of ASK1 and its downstream regulatory target p38/JNK. B5-induced apoptosis was significantly inhibited in the presence of N-acetyl-l-cysteine. Microscopic examination of B5-treated cells revealed increased presence of cytoplasmic vacuoles. The ability of B5 to activate autophagy in cells was subsequently confirmed by cell staining with acridine orange, accumulation of LC3-II, and measurement of autophagic flux. Unlike B5-induced apoptosis, autophagy induced by B5 is not ROS-mediated but a role for the AKT and AMPK signaling pathways is implied. In SiHa cells but not CaSki cells, B5-induced apoptosis was promoted by autophagy. These data suggest that the anticarcinogenic effects of B5 is mediated by complex interplay between cellular mechanisms governing redox homeostasis, apoptosis and autophagy.
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, China.
authors.forename: Fang-Yuan
authors.initials: FY
authors.lastname: Shao
authors.affiliation: Institute of Natural Medicine & Green Chemistry, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, China.
authors.forename: Zhi-Yun
authors.initials: ZY
authors.lastname: Du
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Dong-Lei
authors.initials: DL
authors.lastname: Ma
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Wen-Bo
authors.initials: WB
authors.lastname: Chen
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, China.
authors.forename: Wu-Yu
authors.initials: WY
authors.lastname: Fu
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, China.
authors.forename: Bi-Bo
authors.initials: BB
authors.lastname: Ruan
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Rui
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Jia-Xuan
authors.initials: JX
authors.lastname: Zhang
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Nai Sum
authors.initials: NS
authors.lastname: Wong
authors.affiliation: University of the Chinese Academy of Sciences, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Man-Mei
authors.initials: MM
authors.lastname: Li
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Qiu-Ying
authors.initials: QY
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Zhou
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Hai-Zhao
authors.initials: HZ
authors.lastname: Yan
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Yi-Fei
authors.initials: YF
authors.lastname: Wang
authors.affiliation: Center for Drug Discovery, Northeastern University, Boston, MA, USA.
authors.forename: Chang-Yan
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Guangzhou Jinan Biomedicine Research and Development Center, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, China.
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Chen
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003474:Curcumin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013880:Thioredoxin-Disulfide Reductase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*
chemical_list: D000970:Antineoplastic Agents; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D013880:Thioredoxin-Disulfide Reductase; D003474:Curcumin
keywords: apoptosis; cervical cancer; curcumin analog; thioredoxin reductase