Metformin potentiates arsenic disulfide in diffuse large B-cell lymphoma: modulation of BAX/BCL-2 apoptotic pathway...

Arsenic disulfide (As₂S₂) inhibits proliferation and induces apoptosis in diffuse large B-cell lymphoma (DLBCL) cells, its clinical application is constrained by toxicity. Metformin has also been reported to exert antitumor effects across various malignancies. This study investigated whether metformin potentiates the anti-lymphoma efficacy of As₂S₂ in DLBCL cells and evaluated associated alterations in apoptosis-related markers and Hedgehog signaling molecules.

DLBCL cell lines (DB and SU-DHL-4) were treated with metformin and/or As₂S₂. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay, apoptosis was determined by Annexin V/propidium iodide (PI) flow cytometry, and drug interactions were analyzed using the Bliss independence model and CompuSyn software. The expression levels of BAX, BCL-2, SMO, GLI1, and GLI2 were analyzed by quantitative real-time PCR and Western blotting.

Both metformin and As₂S₂ inhibited DLBCL cell proliferation in a dose- and time-dependent manner. Combination treatment resulted in significantly greater growth inhibition in both cell lines compared with either monotherapy, with synergistic effects confirmed by both Bliss and CompuSyn analyses. Furthermore, the combination significantly increased apoptosis relative to single-agent treatments. At the molecular level, combined treatment was associated with a pro-apoptotic shift in the BAX/BCL-2 ratio and downregulation of Hedgehog pathway components, including SMO, GLI1, and GLI2, with more pronounced changes observed at the protein level.

Metformin enhances the anti-proliferative and pro-apoptotic effects of As₂S₂ in DLBCL cells in vitro. These effects are associated with modulation of the BAX/BCL-2 axis and suppression of Hedgehog pathway-related molecules. Further studies are warranted to elucidate the underlying mechanisms and to evaluate efficacy and safety in vivo.