Investigating therapeutic efficacy of dacarbazine and temozolomide, alone and in combination with siRNA in A375 human melanoma cell line.

OBJECTIVES

Melanoma is one of the most aggressive and deadly skin cancers. Despite advances, effective melanoma treatment is challenging, often requiring a shift from individual therapies to combination approaches. This study explores whether combining dacarbazine (DTIC) and temozolomide (TMZ) with the siRNA approach holds promise for melanoma treatment.

MATERIALS AND METHODS

To determine the IC values of DTIC and TMZ, the A375 cell line was treated with different drug concentrations for 24-72 hr. The best exposure time of BRAF siRNA transfection was performed. Subsequently, cell viability (using the MTT assay), apoptosis (by flow cytometry), and gene expression levels of B-Raf proto-oncogene, serine/threonine kinase (), caspase 3 (), and phosphoinositide-3-kinase regulatory subunit 3 () genes (by quantitative real-time PCR) were assessed in the treated groups (i.e., control, negative controls, DTIC alone, TMZalone, DTIC+ TMZ, BRAF(V600E)siRNA alone, siRNA+ DTIC, siRNA+ TMZ, and siRNA+ DTIC+ TMZ groups).

RESULTS

Cell viability significantly decreased in the chemotherapy-only and siRNA+drug groups, although no difference was observed between them. The apoptosis percentage in all treated groups indicated a significant difference compared to the control group. The expression of the gene notably decreased in the BRAF () siRNA +drug groups compared to the chemotherapy groups. Despite overexpression of in the chemotherapy-treated groups, the most effective enhancement was noted in the siRNA+DTIC+TMZ group (<0.0001). The mean expression of the gene in siRNA+chemotherapy groups revealed a notable reduction.

CONCLUSION

These findings suggest that the siRNA-transfected treatment groups have the potential to provide therapeutic effects comparable to those of chemotherapy.