Abstract 3985: GDF15 expression level impacts the canonical pathways of the tumor microenvironment and ovarian tumors with wild-type p53 in response to chemotherapy

Abstract

Abstract Background The standard treatment for ovarian cancer is surgery, followed by chemotherapy with a platinum agent, such as cisplatin or carboplatin, and a taxane, such as paclitaxel. We previously observed that patients with ovarian cancer that was wild-type for p53 had a lower survival rate than did those with p53 mutations. A better understanding of the molecular changes that occur in epithelial ovarian cancer cells with wild-type p53 in response to cisplatin treatment could reveal a novel mechanism of chemoresistance. Therefore, we might be able to develop novel strategy to overcome chemoresistance. Methods Gene expression profiling was performed on the wild-type p53 ovarian cancer cell line A2780 to identify genes that are highly induced by cisplatin. Growth differentiation factor 15 (GDF15) was identified as being highly induced by cisplatin or carboplatin. This finding was validated in a panel of wild-type and mutant p53 ovarian cancer cell lines. Mouse orthotopic models were used to further investigate the induction of GDF15 by cisplatin in vivo and the effect of GDF15 knockdown (GDF15-KD) on tumor growth and cisplatin response. A novel analysis was performed of RNAseq data generated from tumors formed in cisplatin-treated orthotopic mouse models to understand the tumor and stromal cell signaling changes. Results The induction of GDF15 was demonstrated in vivo, and the serum level of GDF15 after cisplatin treatment was also found to be significantly up-regulated in an A2780 ovarian cancer orthotopic mouse model. More importantly, cisplatin treatment was more effective in shrinking the mouse tumors developed from GDF15-KD A2780 cell line than did control tumors. Histopathological and novel RNAseq analyses of mouse tumors revealed that GDF15-KD tumors had a lower stromal component than did control tumors after cisplatin treatment. GDF15-KD tumors also had a different repertoire of activated and inhibited canonical pathways in their stromal cell and cancer cell components than did control tumors in response to cisplatin treatment. Conclusions GDF15 expression in wild-type p53 ovarian cancer cells can modulate the canonical pathways in the tumor microenvironment in response to cisplatin and may be a mechanism of chemoresistance. Targeting GDF15 signaling could be a novel strategy to enhance the effectiveness of chemotherapy. Citation Format: Daisy I. Izaguirre, Yvonne TM Tsang, Eucharist H. Kun, David M. Gershenson, Kwong-Kwok Wong. GDF15 expression level impacts the canonical pathways of the tumor microenvironment and ovarian tumors with wild-type p53 in response to chemotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3985.