In vitro and in vivo inhibition of liver cancer cells by 1,25-dihydroxyvitamin D-3

Inhibitory effects of 1,25-dihydroxyvitamin D-3 (1,25-(OH)(2)D-3) on the pr oliferation of a variety of cancer cell lines have been extensively reporte d. We have studied the effect of 1,25-(OH)(2)D-3 (10(-11)-10(-6) M) on the proliferation of a number of human and rat liver cancer cell lines. Additio nally, the effect of 1,25-(OH)(2)D-3 (0.02-0.5 mu g/kg per day) on the rate of growth of liver cancer cell line xenografts in nude mice was also inves tigated. In vitro, proliferation of Hep-3B, PLC/PRF/5, and SKHEP-1 cells wa s significantly inhibited by 1,25-(OH)(2)D-3, while HTC and Novikoff cells were more resistant to the inhibitory effects of the drug. In vivo, treatme nt of SKHEP-1 tumor bearing nude mice with different doses of 1,25-(OH)(2)D -3 significantly retarded tumor growth without the development of hypercalc emia. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.