Inhibition of the proliferation of androgen-dependent sc-3 cells by methylcobalamin

Methylcobalamin decreased the proliferation of androgen-dependent SC-3 cells, derived from androgen-dependent mouse mammary tumor SC115, in a dose dependent manner at high concentrations without remarkable change of the cell viability. The androgen-induced growth factor activity in the conditioned medium of SC-3 cells cultured in the presence of androgen was shown to be decreased by the addition of methylcobalamin. In SC-3 cells incubated with [methyl-H-3]methylcobalamin, [H-3]methyl moiety was incorporated into the DNA fraction. These results indicate an antiproliferative effect of methylcobalamin on SC-3 cells at high concentrations and suggest a possibility that methylcobalamin can act as a donor of methyl moiety into DNA.