Genistein and Curcumin Inhibit Proliferation and Invasiveness in BRAFV600E Mutant and Wild-Type Melanoma Cells: Insights into Their Anticancer Effects

Background/objectives: Melanoma is one of the deadliest forms of malignant cancers; ultraviolet radiation exposure together with genetic mutations, such as BRAF, represent the main risk factors and are involved in metastatic dissemination. Previous studies demonstrated the anti-emetic and anti-proliferative effects of the flavonoid genistein and the turmeric curcumin in cancers. This study aimed at investigating the anticancer effects of curcumin, genistein and their association in melanoma cells. Methods: Human A375 and CHL-1 cell lines were cultured and treated with different concentrations of curcumin or genistein or curcumin + genistein for 24 h according to IC50. Results: Genistein and curcumin induced cell death, as demonstrated by MTT assay and FDA/PI staining. The anti-apoptotic protein Bcl-2 was significantly reduced after curcumin and curcumin + genistein treatment, but unexpectedly not with genistein alone. Curcumin and genistein significantly increased DNA fragmentation, thus indicating apoptosis induction. Moreover, comet assay confirmed that curcumin and genistein stimulated cell death, as quantified by measuring the displacement between the 'comet head' and the resulting 'tail'. FAK protein expression was significantly reduced by genistein and curcumin in CHL-1 cells and after the treatment with genistein + curcumin in the most aggressive A375 cells. These anti-proliferative effects were confirmed by scratch assay and phospho-p38 reduction. Moreover, both curcumin and genistein alone and in association inhibited cell adhesion, thus indicating that these nutraceuticals could reduce invasion and metastasis. Conclusion: The obtained results provided new insights for the anticancer effects of genistein and curcumin, which could be used to improve therapeutic adherence and drug response.