β-Carotene down-regulates inducible nitric oxide synthase gene expression and induces apoptosis by suppressing bcl-2 expression and activating caspase-3 and p53 genes in B16F-10 melanoma cells.

The objective of this research was to assess the effect of β-carotene on the regulation of nitric oxide (NO) and tumor necrosis factor (TNF)-α production and stimulation of apoptosis in B16F-10 melanoma cells. β-Carotene at a concentration of 10 μg/mL could significantly (P < .01) inhibit NO and TNF-α production in B16F-10 melanoma cells. This was further evidenced by the regulatory effect of β-carotene on the inhibition of inducible nitric oxide synthase gene expression in B16F-10 cells. We investigated the effect of β-carotene on induction of apoptosis in B16F-10 cells. Incubation of B16F-10 cells with β-carotene showed the presence of apoptotic bodies and induced DNA fragmentation. Furthermore, β-carotene showed inhibitory effect on bcl-2 expression and up-regulated p53 and caspase-3 gene expression in B16F-10 melanoma cells. In conclusion, the observed results suggest that β-carotene could regulate NO and TNF-α production and stimulates apoptosis in B16F-10 melanoma cells by regulating bcl-2, p53, and caspase-3 genes.