SIRT3 participates in glucose metabolism interruption and apoptosis induced by BH3 mimetic S1 in ovarian cancer cells

Abstract

The Bcl-2 antiapoptotic proteins are important cancer therapy targets; however, their role in cancer cell metabolism remains unclear. We found that the BH3-only protein mimetic S1, a novel pan Bcl-2 inhibitor, simultaneously interrupted glucose metabolism and induced apoptosis in human SKOV3 ovarian cancer cells, which was related to the activation of SIRT3, a stress-responsive deacetylase. S1 interrupted the cellular glucose metabolism mainly through causing damage to mitochondrial respiration and inhibiting glycolysis. Moreover, S1 upregulated the gene and protein expression of SIRT3, and induced the translocation of SIRT3 from the nucleus to mitochondria. SIRT3 silencing reversed the effects of S1 on glucose metabolism and apoptosis through increasing the level of HK-II localized to the mitochondria, while a combination of the glycolysis inhibitor 2-DG and S1 intensified the cytotoxicity through further upregulation of SIRT3 expression. This study underscores an essential role of SIRT3 in the antitumor effect of Bcl-2 inhibitors in human ovarian cancer through regulating both metabolism and apoptosis. The manipulation of Bcl-2 inhibitors combined with the use of classic glycolysis inhibitors may be rational strategies to improve ovarian cancer therapy.

Dicumarol inhibits PDK1 and targets multiple malignant behaviors of ovarian cancer cells

“…The in vitro cell viability was examined using the standard MTT assay, as described previously [41]. Briefly, SKOV3 or A2780 cells were seeded in 96-well plates at 8000 cells/well.…”

“…Following incubation of the membranes with horseradish peroxidase-conjugated secondary antibodies for 2 h, the signals were detected using enhanced chemiluminescence reagents followed by Syngene Bio Imaging (Synoptics, Cambridge, UK). The band densities were measured using Syngene Bio Imaging tools, as described previously [41]. …”

“…In brief, SKOV3 cells were cultured in 24-well plates and treated as indicated for an additional 24 h. The cells were washed with cold PBS and fixed using 4% (w/v) paraformaldehyde for 15 min. The plates were then incubated with 1 μg/mL Hoechst 33343 (Santa Cruz) for 10 min and observed under a fluorescence microscope (IX-71, Olympus), as described previously [41]. …”

“…The culture medium was then collected, and the glucose and lactate concentrations were measured with a glucose assay kit and a lactate assay kit (Beyotime, Jiangsu, China), respectively. The data were normalized by the corresponding total protein amounts from each sample, as described previously [41]. …”

“…Each treatment was repeated in three wells. The OCR and ECAR were measured using oxygen-sensitive (Mito-Xpress) and pH-sensitive (pH-Xtra) fluorescent probes (Luxcel Bioscience, Cork, Ireland), as described previously [41]…”