title: Overexpression of DDB2 enhances the sensitivity of human ovarian cancer cells to cisplatin by augmenting cellular apoptosis.
abstract: Cisplatin is one of the most widely used anticancer agents, displaying activity against a wide variety of tumors. However, development of drug resistance presents a challenging barrier to successful cancer treatment by cisplatin. To understand the mechanism of cisplatin resistance, we investigated the role of damaged DNA binding protein complex subunit 2 (DDB2) in cisplatin-induced cytotoxicity and apoptosis. We show that DDB2 is not required for the repair of cisplatin-induced DNA damage, but can be induced by cisplatin treatment. DDB2-deficient noncancer cells exhibit enhanced resistance to cell growth inhibition and apoptosis induced by cisplatin than cells with fully restored DDB2 function. Moreover, DDB2 expression in cisplatin-resistant ovarian cancer cell line CP70 and MCP2 was lower than their cisplatin-sensitive parental A2780 cells. Overexpression of DDB2 sensitized CP70 cells to cisplatin-induced cytotoxicity and apoptosis via activation of the caspase pathway and downregulation of antiapoptotic Bcl-2 protein. Further analysis indicates that the overexpression of DDB2 in CP70 cells downregulates Bcl-2 expression through decreasing Bcl-2 mRNA level. These results suggest that ovarian cancer cells containing high level of DDB2 become susceptible to cisplatin by undergoing enhanced apoptosis.
authors.affiliation: Department of Radiology, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Bassant M
authors.initials: BM
authors.lastname: Barakat
authors.forename: Qi-En
authors.initials: QE
authors.lastname: Wang
authors.forename: Chunhua
authors.initials: C
authors.lastname: Han
authors.forename: Keisha
authors.initials: K
authors.lastname: Milum
authors.forename: De-Tao
authors.initials: DT
authors.lastname: Yin
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhao
authors.forename: Gulzar
authors.initials: G
authors.lastname: Wani
authors.forename: El-Shaimaa A
authors.initials: el-SA
authors.lastname: Arafa
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: El-Mahdy
authors.forename: Altaf A
authors.initials: AA
authors.lastname: Wani
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002945:Cisplatin / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000970:Antineoplastic Agents; C117669:DDB2 protein, human; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D002945:Cisplatin