Targeting Ras Signaling via Carbonic Anhydrase IX Inhibition: Differential Impact of Acetazolamide on Clear Cell Renal Carcinoma and Melanoma Cells

Objective: To investigate the effect of carbonic anhydrase IX (CA-IX) inhibition by acetazolamide (AAZ) on Ras protein expression in clear cell renal carcinoma and melanoma cell lines. Materials and Methods: CAKI-2 (clear cell renal carcinoma) and A375 (melanoma) cell lines were cultured and treated with AAZ, rapamycin (RAPA), or vemurafenib (VMF). Cytotoxicity was assessed using the WST-1 assay. CA-IX inhibition was confirmed by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence staining. Ras protein expression levels were determined by Western blot analysis. Results: In CAKI-2 cells, there was no significant change in Ras protein expression following AAZ or RAPA treatment (p>0.05). In A375 melanoma cells, AAZ treatment significantly reduced Ras protein levels compared with both the untreated control and VMF-treated groups (p<0.001). Conclusion: AAZ significantly reduced Ras protein expression in A375 melanoma cells. These findings provide evidence supporting the role of AAZ in regulating Ras-MAPK signaling in melanoma.