20-hydroxyvitamin D₃ inhibits proliferation of cancer cells with high efficacy while being non-toxic.

AIM: To define the potential utility of 20-hydroxyvitamin D(3) (20(OH)D(3)) as a tumorostatic agent, we assessed its in vitro antiproliferative activity and its in vivo toxicity.
MATERIALS AND METHODS: The antitumor activity of 20(OH)D(3) was tested against breast and liver cancer cell lines using colony formation assays. To assess in vivo toxicity, mice were injected with 5-30 μg/kg 20(OH)D(3) intraperitoneally each day for 3 weeks. Blood and organ samples were collected for clinical pathology analyses.
RESULTS: 20(OH)D(3) displays similar tumorostatic activity towards MDA-MB-453 and MCF7 breast carcinomas, and HepG2 hepatocarcinoma, in a dose-dependent manner. This compound is not hypercalcemic, does not cause detectable toxicities in liver, kidney, or blood chemistry in mice at a dose as high as 30 μg/kg. In contrast, both 25(OH)D(3) and 1,25(OH)(2)D(3) caused severe hypercalcemia at a dose of 2 μg/kg.
CONCLUSION: 20(OH)D(3) possesses high efficacy for inhibiting cancer cell proliferation in vitro and is non-toxic in vivo, supporting its further development as a potential anticancer therapeutic agent.