Quercetin-Arctigenin Co-Treatment Induces Mitochondrial Dysfunction and Apoptotic Cell Death Through Metabolic Stress...

Malignant mesothelioma is an aggressive cancer with limited therapeutic options, highlighting the need for novel strategies targeting metabolic vulnerabilities. Natural polyphenols have gained attention due to their ability to modulate cellular metabolism and apoptosis-related signaling pathways. In this study, we investigated the combined anticancer effects of quercetin (QUE) and arctigenin (ATG) in human malignant mesothelioma cells. QUE and ATG reduced the viability of MSTO-211H cells in a time-dependent manner, while non-malignant mesothelial MeT-5A cells showed relatively limited sensitivity under the tested conditions. Compared with single treatment, the combination treatment further enhanced growth inhibition, with combination index analysis suggesting a potential synergistic interaction. Co-treatment significantly decreased intracellular ATP levels and increased caspase-3/7 activity, suggesting metabolic stress-associated apoptotic responses. Annexin V analysis confirmed increased apoptotic cell populations following combination treatment. Western blot analysis demonstrated reduced expression of anti-apoptotic proteins Mcl-1 and Bcl-xL, along with increased cleavage of caspase-3 and PARP, consistent with involvement of intrinsic apoptosis-associated signaling pathways. In addition, increased phosphorylation of AMPK and altered expression of mitochondrial oxidative phosphorylation (OXPHOS) complex proteins were associated with potential alterations in mitochondrial respiratory protein expression. Collectively, these findings suggest that QUE and ATG co-treatment is associated with increased apoptotic cell death in malignant mesothelioma cells in association with metabolic stress-related mitochondrial functional alterations.