Signaling through the vitamin D receptor has been shown to be biologically active and important in a number of preclinical studies in prostate and other cancers. Epidemiologic data also indicate that vitamin D signaling may be important in the cause and prognosis of prostate and other cancers. These data indicate that perturbation of vitamin D signaling may be a target for the prevention and treatment of prostate cancer. Large studies of vitamin D supplementation will be required to determine whether these observations can be translated into prevention strategies. This paper reviews the available data in the use of vitamin D compounds in the treatment of prostate cancer. Clinical data are limited which support the use of vitamin D compounds in the management of men with prostate cancer. However, clinical trials guided by existing preclinical data are limited.
Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; Calcifediol/blood* ; Calcitriol/therapeutic use* ; Clinical Trials as Topic ; Ergocalciferols/therapeutic use* ; Humans ; Male ; Prostatic Neoplasms/prevention & control* ; Signal Transduction ; Vitamin D/metabolism* ; Vitamin D Deficiency/epidemiology*

The active metabolite of vitamin D, 1,25-dihydroxyvitamin D3 (calcitriol), inhibits the growth of several types of human cancer cells in vitro, but its therapeutic use is limited because it causes hypercalcemia. Among its analogs, 19-nor-1,25-dihydroxyvitamin D2 (paricalcitol), has fewer calcemic effects and exhibits an activity equipotent to that of calcitriol. We assessed the antitumor and anti-inflammatory effects of paricalcitol in gastric cancer cells, and evaluated the potential role of vitamin D in the treatment of peritoneal metastatic gastric cancer. In this study, treatment with paricalcitol inhibited gastric cancer cell growth and induced cell cycle arrest. Paricalcitol also induced apoptosis and showed anti-inflammatory activity. Moreover, the growth of intraperitoneal metastases in vivo was reduced in mice treated with paricalcitol. 18F-FDG uptake was significantly lower in the paricalcitol group compared to control group (SUV; control group 13.2 +/- 5.3 vs paricalcitol group 4.5 +/- 3.0). Intraperitoneal tumor volume was significantly lower in paricalcitol treated mice (control group 353.2 +/- 22.9 mm3 vs paricalcitol group 252.0 +/- 8.4 mm3). These results suggest that the vitamin D analog, paricalcitol, has anticancer activity on gastric cancer cells by regulation of the cell cycle, apoptosis, and inflammation.
Animals ; Antineoplastic Agents/chemistry/*pharmacology/therapeutic use ; Apoptosis/drug effects ; Cell Cycle Checkpoints/drug effects ; Cell Cycle Proteins/metabolism ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Disease Models, Animal ; Ergocalciferols/chemistry/*pharmacology/therapeutic use ; Fluorodeoxyglucose F18/chemistry/diagnostic use ; Humans ; Mice ; Mice, Inbred BALB C ; Peritoneal Neoplasms/drug therapy/*secondary ; Positron-Emission Tomography ; Stomach Neoplasms/drug therapy/*pathology ; Transplantation, Heterologous