Abstract NT-105: ANTI-TUMOUR EFFECTS OF ALL-TRANS RETINOID ACID, AN ANNEXIN A2-S100A10 PATHWAY INHIBITOR ON SEROUS OVARIAN CANCER

Annexin A2 is increased in serous ovarian cancer and plays an essential role in ovarian cancer invasion and metastasis. In combination with S100A10, annexin A2 plays an important role in the plasminogen activator system regulating plasmin production. The aim of this study was to investigate the potential utility of all-trans retinoid acid (ATRA), an inhibitor of the annexin A2-S100A10 signalling pathway, as a new therapeutic against serous ovarian cancer. Survival of serous ovarian cancer cells (OVCAR-3, OV-90, & OAW28) was significantly decreased by ATRA treatment (1-5µM). ATRA (1µM) also significantly decreased proliferation (Ki67 positivity, p=0.0034), S100A10 protein levels (p=0.0273), and increased cell apoptosis (cleaved caspase-3 positivity, p=0.0024) in serous ovarian cancer tissues using an ex vivo explant assay. In OAW28 cells, reduced cell survival following ATRA treatment was associated with a reduction of S100A10 protein levels, S100A10 and annexin A2 membrane localization, plasmin generation, motility and invasion. In contrast, ATRA inhibited OV-90 cell survival and invasion but did not affect plasmin activation or S100A10 and annexin A2 membrane localization or protein levels. These findings suggest that ATRA inhibits serous ovarian cancer proliferation and invasion via both S100A10 dependant and S100A10 independent mechanisms. Our results show that ATRA has promising potential as a novel therapy against serous ovarian cancer that warrants further evaluation. Citation Format: Noor A Lokman,Rachel Ho, Kavyadharshini Gunasegaran, Wendy M Bonner , Martin K Oehler, Carmela Ricciardelli. ANTI-TUMOUR EFFECTS OF ALL-TRANS RETINOID ACID, AN ANNEXIN A2-S100A10 PATHWAY INHIBITOR ON SEROUS OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-105.