Oxidative Stress-Mediated Mitochondrial Dysfunction Drives Genistein-Induced Apoptosis in TM4 Sertoli and ELT3 Leiomyoma Cells

Abstract

Genistein (GEN) exhibits concentration- and cell-type-dependent biological activities; however, the mechanisms underlying its cytotoxicity remain incompletely understood. This study investigated whether oxidative stress-mediated mitochondrial dysfunction contributes to GEN-induced apoptosis in TM4 mouse Sertoli cells and ELT3 rat leiomyoma cells. Cells were exposed to GEN (30 or 100 µM) for 48 h. Cytotoxicity, oxidative stress, mitochondrial function, and apoptosis were assessed by measuring cell viability, lactate dehydrogenase release, reactive oxygen species (ROS), malondialdehyde, glutathione reductase activity, mitochondrial membrane potential (ΔΨm), intracellular ATP, apoptosis-related gene expression, and caspase-3/-9 activities. The involvement of oxidative stress was examined using N-acetyl-L-cysteine (NAC). GEN reduced cell viability, antioxidant capacity, ΔΨm, and ATP content while increasing membrane damage, ROS accumulation, and lipid peroxidation in both cell lines. These changes were accompanied by upregulation of Bax, Tp53, caspase-3, and caspase-9; downregulation of Bcl-2; and increased caspase-3/-9 activities. NAC pretreatment attenuated these alterations, supporting ROS as an upstream mediator. Notably, TM4 cells were approximately 4.4-fold more sensitive to GEN than ELT3 cells at 48 h. Collectively, the findings support a ROS-dependent mitochondrial apoptotic response under elevated in vitro GEN exposure but do not establish selective antitumor cytotoxicity or direct physiological relevance.