Voltage-Gated Sodium Channels as Potential Biomarkers and Therapeutic Targets for Epithelial Ovarian Cancer

Abnormal ion channel expression distinguishes several types of carcinoma. Here, we explore the relationship between voltage-gated sodium channels (VGSC) and epithelial ovarian cancer (EOC). We find that EOC cell lines express most VGSC, but at lower levels than fallopian tube secretory epithelial cells (the cells of origin for most EOC) or control fibroblasts. Among patient tumor samples, lower SCN8A expression was associated with improved overall survival (OS) (median 111 vs. 52 months; HR 2.04 95% CI: 1.21-3.44; p = 0.007), while lower SCN1B expression was associated with poorer OS (median 45 vs. 56 months; HR 0.69 95% CI 0.54-0.87; p = 0.002). VGSC blockade using either anti-epileptic drugs or local anesthetics (LA) decreased the proliferation of cancer cells. LA increased cell line sensitivity to platinum and taxane chemotherapies. While lidocaine had similar additive effects with chemotherapy among EOC cells and fibroblasts, bupivacaine showed a more pronounced impact on EOC than fibroblasts when combined with either carboplatin (ΔAUC -37% vs. -16%, p = 0.003) or paclitaxel (ΔAUC -37% vs. -22%, p = 0.02). Together, these data suggest VGSC are prognostic biomarkers in EOC and may inform new targets for therapy.