Bcl2 inhibitor ABT737 reverses the Warburg effect via the Sirt3-HIF1α axis to promote oxidative stress-induced apoptosis in ovarian cancer cells

Abstract

Aims: Compared to normal cells, tumor cells maintain higher concentrations of reactive oxygen species (ROS) to support proliferation, invasion, and metastasis. Chemotherapeutic drugs often induce tumor cell apoptosis by increasing intracellular ROS concentrations to highly toxic levels. ABT737, which inhibits the apoptosis regulator B cell lymphoma 2 (Bcl2), increases the sensitivity of ovarian cancer cells to chemotherapeutic drugs by regulating the glucose metabolism, but the underlying mechanisms remain unclear. Therefore, we aimed to determine whether ABT737 promoted H₂O₂-induced tumor cell apoptosis by reversing glycolysis in ovarian cancer cells.

Main methods: SKOV3 ovarian cancer cells were treated with H₂O₂, ABT737, or both. Cell viability was compared using methyl thiazolyl tetrazolium (MTT), and flow cytometry was used to detect differences in apoptosis, ROS, and mitochondrial membrane potential. The relative expression levels of proteins associated with apoptosis and the glucose metabolism were measured using immunoblotting. Finally, glucose uptake and lactate secretion were measured using kits and compared.

Key findings: ABT737 downregulated proteins associated with glucose uptake (GLUT1) and glycolysis (LHDA, PKM2 and HK2) via the Sirt3-HIF1α axis, reducing glucose uptake and lactate secretion in SKOV3 cells. This reversed glycolysis in the tumor cells, and promoted H₂O₂-induced apoptosis.

Significance: The Bcl2 inhibitor ABT737 enhanced the anti-tumor effect of oxidative stress by reversing the Warburg effect in ovarian cancer cells, providing powerful theoretical support for further clinical applications of Bcl2 inhibitors.

Keywords: ABT737; Apoptosis; B-cell lymphoma 2; Glycolysis; Oxidative stress; Warburg effect.