title: Induction of autophagy contributes to cisplatin resistance in human ovarian cancer cells.
abstract: Cisplatin resistance is a major challenge in the clinical treatment of ovarian cancer, of which the underlying mechanisms remain unknown. The aim of the present study was to explore the role of autophagy in cisplatin resistance in ovarian cancer cells. A2780cp cisplatin-resistant ovarian carcinoma cells and the A2780 parental cell line, were used as a model throughout the present study. The cell viability was determined using a water soluble tetrazolium salt-8 assay, and western blot analysis was performed to determine the protein expression levels of microtubule-associated protein 1 light chain 3 (LC3 I and LC3 II), and Beclin 1. Beclin 1 small interfering (si)RNA and 3-methyladenine (3-MA) were used to determine whether inhibition of autophagy may re-sensitize cisplatin-resistant cells to cisplatin. The ultrastructural analysis of autophagosomes was performed using transmission electron microscopy, and apoptosis was measured by flow cytometry. In both A2780cp and A2780 cells, cisplatin induced the formation of autophagosomes and upregulated the expression levels of autophagy protein markers, LC3 II and Beclin 1. However, the levels of autophagy were significantly higher in A2780cp cells, as compared with the A2780 cells. The combined treatment of cisplatin with 3-MA, the autophagy pharmacological inhibitor, increased the cell death rate, but had no effects on apoptosis, as compared with cisplatin treatment alone in A2780cp cells. However, inhibition of autophagy by siRNA knockdown of Beclin 1 expression enhanced cisplatin-induced cell death and apoptosis. The findings of the present study suggest that autophagy has a protective role in human ovarian cancer cells, and that targeting autophagy may promote chemotherapeutic sensitivity.
authors.affiliation: Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011, P.R. China.
authors.forename: Lingjie
authors.initials: L
authors.lastname: Bao
authors.affiliation: Department of Pharmacology and Toxicology, University of Arizona, AZ 85721, Arizona, USA.
authors.forename: Melba C
authors.initials: MC
authors.lastname: Jaramillo
authors.affiliation: Department of Obstetrics and Gynecology, Shanghai First People's Hospital, Jiaotong University, Shanghai 200080, P.R. China.
authors.forename: Zhenbo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011, P.R. China.
authors.forename: Yunxi
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, P.R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yao
authors.affiliation: Department of Pharmacology and Toxicology, University of Arizona, AZ 85721, Arizona, USA.
authors.forename: Donna D
authors.initials: DD
authors.lastname: Zhang
authors.affiliation: Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011, P.R. China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Yi
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002945:Cisplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering
chemical_list: D000970:Antineoplastic Agents; D034741:RNA, Small Interfering; D002945:Cisplatin