Nutlin-3a: A Potential Therapeutic Opportunity for TP53 Wild-Type Ovarian Carcinomas

• DOI: 10.1371/journal.pone.0135101
• Publication Date: 2015-08-06T18:10:56Z
• Authors: Erin K. Crane; Suet-Yan Kwan; Daisy I. Izaguirre; Yvonne T. M. Tsang; Lisa K. Mullany; Zhifei Zu; JoAnne S. Richards; David M. Gershenson; Kwong-Kwok Wong
• Keywords: Cyclin-Dependent Kinase Inhibitor p21; Cell Survival; Science; Antineoplastic Agents; Apoptosis; Piperazines; Inhibitory Concentration 50; 03 medical and health sciences; 0302 clinical medicine; Cell Line, Tumor; Humans; 2. Zero hunger; Q; Ovary; R; Imidazoles; Proto-Oncogene Proteins c-mdm2; Exons; Sequence Analysis, DNA; Introns; 3. Good health; Gene Expression Regulation, Neoplastic; Mutation; Medicine; Female; Tumor Suppressor Protein p53; Research Article; Signal Transduction

Epithelial ovarian cancer is a diverse molecular and clinical disease, yet standard treatment is the same for all subtypes. TP53 mutations represent a node of divergence in epithelial ovarian cancer histologic subtypes and may represent a therapeutic opportunity in subtypes expressing wild type, including most low-grade ovarian serous carcinomas, ovarian clear cell carcinomas and ovarian endometrioid carcinomas, which represent approximately 25% of all epithelial ovarian cancer. We therefore sought to investigate Nutlin-3a--a therapeutic which inhibits MDM2, activates wild-type p53, and induces apoptosis--as a therapeutic compound for TP53 wild-type ovarian carcinomas. Fifteen epithelial ovarian cancer cell lines of varying histologic subtypes were treated with Nutlin-3a with determination of IC50 values. Western Blot (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) analyses quantified MDM2, p53, and p21 expression after Nutlin-3a treatment. DNA from 15 cell lines was then sequenced for TP53 mutations in exons 2-11 including intron-exon boundaries. Responses to Nutlin-3a were dependent upon TP53 mutation status. By qRT-PCR and WB, levels of MDM2 and p21 were upregulated in wild-type TP53 sensitive cell lines, and p21 induction was reduced or absent in mutant cell lines. Annexin V assays demonstrated apoptosis in sensitive cell lines treated with Nutlin-3a. Thus, Nutlin-3a could be a potential therapeutic agent for ovarian carcinomas expressing wild-type TP53 and warrants further investigation.