Mechanistic insights into proteasome inhibitor MG132 induced apoptosis in melanoma A375 cells

Despite advancements in melanoma therapy, the prognosis remains unfavorable for many patients. The proteasome inhibitor MG132 has shown therapeutic potential through pathway regulation, yet its precise mechanisms in melanoma require systematic elucidation. Using A375 melanoma cells, we conducted multi-modal investigations combining cytotoxicity assessment (CCK8), migration analysis (wound healing), apoptosis quantification (flow cytometry), and proteomic profiling (western blot) to dissect MG132's molecular mechanisms. Our findings revealed MG132's potent anti-tumor activity with an IC₅₀ of 1.258 ± 0.06 µM, significantly suppressing cellular migration at therapeutic concentrations. Apoptosis assays demonstrated concentration-dependent effects, with 2 µM treatment inducing early apoptosis in 46.5% and total apoptotic response in 85.5% of cells within 24 h. Mechanistic studies uncovered MG132's dual regulatory capacity: (1) Through MDM2 inhibition, it activated p53/p21/caspase-3 axis while suppressing CDK2/Bcl2, triggering cell cycle arrest and DNA damage cascades; (2) MAPK pathway activation emerged as a critical apoptosis driver. Notably, western blot analysis established dose-responsive modulation of these molecular targets, confirming pathway specificity. Our results position MG132 as a multi-target agent capable of simultaneously disrupting proliferative signaling and activating apoptotic machinery. The observed MAPK-mediated apoptosis mechanism provides novel insights for melanoma therapeutics, suggesting that combinatorial targeting of proteasomal and MAPK pathways may enhance treatment efficacy.