Investigating the Potential for Na+‐H+ Exchanger Isoform 1 (NHE1) Inhibitors as Adjuvant Therapies in the Treatment of Ovarian Cancer

Abstract

Each year in the United States over 200,000 women are diagnosed with ovarian cancer leading to more than 130,000 deaths. A major challenge in ovarian cancer treatment is the development of drug resistance to the therapeutic agents. Increases in the expression and activity Na+‐H+ Exchanger Isoform 1 (NHE1) was recently demonstrated to regulate cell proliferation in ovarian cancer patients. NHE1 is an 815 amino acid transmembrane transport protein that regulates intracellular pH. We hypothesize that combining common ovarian cancer therapeutic agents along with compounds that directly or indirectly inhibit NHE1 will enhance the ability of the therapeutic agents to slow ovarian cancer cell proliferation and migration. Three ovarian adenocarcinoma cell lines; CAOV‐3, SKOV‐3, and OVCAR‐3 are used in this research. Using a proliferation assay, we assessed the impact of different ovarian cancer therapeutics (Rucaparib, Olaparib, Paclitaxel and Cisplatin) in these three cell lines in the presence and absence of inhibitors that decrease NHE1 activity directly or indirectly. Our previous work demonstrated that the NHE1 inhibitor cariporide and a number of protein kinase inhibitors decreased cell proliferation rates in all three cell types. Treatment with Cisplatin reduced cell proliferation most significantly in the CAOV‐3 line. Paclitaxel and Cisplatin each had significant and comparable impacts on the SKOV‐3 and OVCAR‐3 cell lines. Cell migration was evaluated using electric cell‐substrate impedance sensing (ECIS). In the SKOV‐3 and CAOV‐3 cells, inhibition with cariporide and the Rsk inhibitor BID1870 each dramatically reduced the rate of cell migration. The research presented here supports the role of NHE1 in cell proliferation, and for the first time implicates NHE1 in the regulation of cell migration in ovarian cancer cells. Data will be presented that evaluated the potential for the inhibition of NHE1 as an adjuvant therapy in ovarian cancer.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.