Endocrine Abstracts

Introduction: Vitamin D is a hormone related to calcium homeostasis and normal function of the musculoskeletal system. Recently, the extraskeletal actions of vitamin D are the focus of scientific interest. The hormone is thought to possess anticancer properties, these properties being especially related to cancer of the prostate.

Aim: The aim was to study the effect of vitamin D on PC3 prostate cancer cells in vitro.

Methods: The effect of 1,25(OH)₂D₃, 25(OH)D₃, 1α(OH)D₃ and paricalcitol at initial concentrations of 200, 40, 20 and 20 nM, respectively, on PC3 prostate cancer cells was studied in vitro. PC3 cells were incubated for 48 h at 37  °C with progressively decreasing concentrations of 1,25(OH)₂D₃, 25(OH)D₃, 1α(OH)D₃ and paricalcitol. Experiments were also performed with 1,25(OH)₂D₃ at concentrations of 500 nM and 1 μM. PC3 cells were also incubated with progressively decreasing concentrations of 1,25(OH)₂D₃, the initial concentration being 200 nM, in the presence of the antimitotic agent docetaxel 50 nM.

Results: The proliferation of PC3 prostate cancer cells was not affected by 25(OH)D₃, 1α(OH)D₃ and paricalcitol. High concentrations of 1,25(OH)₂D₃ mildly inhibited PC3 proliferation whereas lower concentrations had no effect. The proliferation of PC3 cells was inhibited in the presence of both 1,25(OH)₂D₃ and docetaxel.

Conclusions: In conclusion, 25(OH)D₃ and analogues of vitamin D had no effect on the proliferation of PC3 prostate cancer cells. However, relatively high concentrations of the active hormone 1,25(OH)₂D₃ was shown to inhibit PC3 cells proliferation. It appears, that vitamin D may possess anticancer properties especially related to prostate cancer.