Abstract C084: Genetic polymorphism rs3820282 and WNT4-mediated metabolic plasticity contributes to differential therapy response in ovarian cancer clear carcinoma
Authors: Dexter Julia , Shackleford Madeleine , Robinson Sydney , Sikora Matthew , Bitler Benjamine 
Published: September 2024

Purpose of research: Ovarian clear cell carcinoma (OCCC) is a rare and notoriously chemoresistant gynecologic malignancy that is more likely to affect patients of Asian race. Unlike the more common tubo-ovarian high-grade serous carcinoma, OCCC is rising in incidence. Previous work highlights the increased risk of reproductive pathology associated with single nucleotide polymorphism (SNP) rs3820282, a genetic variant that is also overrepresented in people of Asian race. In particular, rs3820282 results in increased WNT4 expression and is associated with metabolic reprogramming and elevated phospho-AMPK as demonstrated in murine models and primary human tumors. We hypothesize the WNT4/rs3820282 regulatory axis in OCCC mediates the response to chemotherapy via metabolic plasticity. Methods: Using SNP-variant genotype (OVTOKO) and wild-type (TOV-21G) OCCC cell lines, we manipulated the expression of WNT4 via short interfering RNA knockdown and lentiviral overexpression. We evaluated the proliferation and survival of cells in nutrient deprivation conditions. We used Agilent Seahorse to evaluate metabolic outputs of oxidative phosphorylation in the presence of cytotoxic stress conditions (platinum chemotherapy [cisplatin]), antimetabolic agents [metformin and dimethyl malonate], lipid- and glucose-deprived media, and fatty acid oxidation and glycolysis inhibition). We used immunoblotting to measure total AMPK and phospho-AMPK as signals of cellular response to metabolic stress. To evaluate the effect of WNT4 on response to chemotherapy, we measured changes in the half-maximal inhibitory concentration (IC50) of cisplatin. Results: Knockdown and overexpression of WNT4 in variant and wild-type OCCC cells altered cellular proliferation and survival in nutrient deprivation conditions. Seahorse cellular energetics conducted in variant OCCC cells demonstrated that WNT4 knockdown mitigates the metabolic detriment of cytotoxic and metabolic stress conditions with the opposite trend observed in wild-type WNT4 overexpressing OCCC cells. The variant phenotype is consistent with models of high-grade serous carcinoma. Over five experiments, WNT4 knockdown reduced the IC50 of cisplatin in variant cells (mean log fold change -0.29, range -0.91 to 0.07). While WNT4 knockdown led to a modest increase in total AMPK protein expression, in lipid- and glucose-deprived conditions WNT4 loss significantly attenuated phospho-AMPK levels. Conclusions: Genetically variant OCCC cells exposed to metabolic and antineoplastic stressors demonstrate metabolic plasticity which is regulated by WNT4. Knockdown of WNT4 induces metabolic rigidity that may convey increased susceptibility to chemotherapy, as indicated by the WNT4-induced reduction in cisplatin IC50. The SNP is highly prevalent in people of Asian race, and further investigation of this axis of metabolic reprogramming represents an opportunity to further understand an established cancer disparity and improve chemotherapeutic response in ovarian clear cell carcinoma.

Citation Format: Julia Dexter, Madeleine Shackleford, Sydney Robinson, Matthew Sikora, Benjamine Bitler. Genetic polymorphism rs3820282 and WNT4-mediated metabolic plasticity contributes to differential therapy response in ovarian cancer clear carcinoma [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C084.