Nutrient Starvation Sensitizes Human Ovarian Cancer SKOV3 Cells to BH3 Mimetic via Modulation of Mitochondrial Dynamics

The aberrant proliferation of tumor cells necessitates compensatory changes in tumor metabolic processes. Previous studies on tumor growth and metabolism have established a relationship between nutrient stress and Bcl-2 anti-apoptotic proteins, although the mechanisms connecting these processes remain unclear. We induced nutrient deprivation in human ovarian cancer SKOV3 cells by culturing cells in Earle's balanced salt solution (EBSS) as a starvation model. We used EBSS treatment with the BH3 domain of Bcl-2 family proteins (BH3) mimetic ABT737, which targets Bcl-2/Bcl-xL, to examine mitochondrial dynamics and the interactive regulatory mechanisms between nutrition and Bcl-2 proteins. We found that EBSS combined with ABT737 can promote SKOV3 cells to undergo apoptosis and convert tubular mitochondria into small, fragmented morphologies. Bcl-2 family proteins participated in the regulation of mitochondrial fusion and fission through apoptosis, and the decrease of Mcl-1 expression was the key to ABT737 sensitization. Our findings showed that nutrient stress could sensitize SKOV3 cells to ABT737 via regulation of the mitochondrial dynamic balance and interaction of Bcl-2 family proteins. Our data suggest that nutrient starvation combined with the BH3 mimetic ABT737 could reduce the required effective dose of ABT737, and that inhibition of Bcl-2 and Mcl-1 together with nutrient starvation could serve as an effective strategy for the treatment of human ovarian cancer. Anat Rec, 300:326-339, 2017. © 2016 Wiley Periodicals, Inc.