Novel cyclic pentapeptide H-15 induces differentiation and inhibits proliferation in murine melanoma B16 cells.

Sansalvamide A is a cyclic depsipeptide that is isolated from a marine fungus of the Fusarium genus. Sansalvamide A exhibits significant antitumor ability. The molecular formula and molecular weight of the novel sansalvamide A derivative H-15 are C29H44BrN5O6 and 637.2475, respectively. In the present study, H-15 was found to inhibit the proliferation and induce the differentiation of murine melanoma B16 cells. A sulforhodamine B colorimetric assay was used to measure the inhibitory effects of 0.1, 1, 10, 50 and 100 µM H-15 on the B16 cells, and the results revealed that the inhibitory effects of H-15 exerted on the B16 cells occurred in a concentration-dependent manner. In addition, the growth curve model of the B16 cells treated with 50 µM H-15 revealed that the effect of H-15 was also time-dependent. The differentiation morphology of the B16 cells was observed subsequent to treating the cells with H-15. An optical microscope was used to observe the differentiation morphology of the cells. In addition, melanin secretion increased in the B16 cells treated with 50 µM H-15. The expression levels of tyrosinase (TYR) were assayed by western blot analysis, and it was found that the cells treated with 50 µM H-15 for 48 h exhibited increased expression of TYR. The results of the present study indicated that H-15 may induce the differentiation of B16 cells.