BID- and BAX-mediated mitochondrial pathway dominates A-1331852-induced apoptosis in senescent A549 cells

Area of Science:

• Oncology
• Cell Biology
• Molecular Medicine

Background:

• Senescent tumor cells exhibit increased migration and invasion, contributing to tumor recurrence and drug resistance.
• Targeting senescent cells is a promising strategy to overcome treatment challenges in cancer therapy.

Purpose of the Study:

• To investigate the efficacy of BH3 mimetics in eliminating senescent A549 lung cancer cells.
• To elucidate the molecular mechanisms underlying BH3 mimetic-induced cell death in senescent cancer cells.

Main Methods:

• Doxorubicin was used to induce senescence in A549 cells, confirmed by SA-β-Gal staining and P16 expression.
• Cell viability was assessed using CCK-8 and crystal violet staining to evaluate the effect of A-1331852.
• Apoptosis was analyzed through caspase activity, mitochondrial membrane potential, PARP cleavage, and Western blotting for BID and BAX.
• Fluorescence resonance energy transfer (FRET) was employed to study protein-protein interactions (BCL-xL, tBID, BAX).

Main Results:

• The BH3 mimetic A-1331852 selectively killed doxorubicin-induced senescent A549 cells without affecting proliferating cells.
• A-1331852 triggered caspase-dependent apoptosis, characterized by nuclear condensation, reduced mitochondrial membrane potential, and PARP cleavage.
• Upregulation of BID and BAX expression was observed, indicating their involvement in A-1331852-induced apoptosis.
• FRET analysis revealed that A-1331852 disrupts the binding of BCL-xL to both tBID and BAX, leading to BAX oligomerization and mitochondrial apoptosis.

Conclusions:

• A-1331852 effectively eliminates senescent A549 cells, suggesting its potential as a therapeutic agent against senescent tumor cells.
• The mechanism involves A-1331852-induced apoptosis via the mitochondrial pathway, mediated by altered interactions between BCL-xL, tBID, and BAX.
• This study provides novel insights into targeting senescent cancer cells by modulating protein interactions within the BCL-2 family.