Calcitriol 1,dihydroxyvitamin D 3 , the hormonally active metabolite of vitamin D, exerts many anticancer effects in breast cancer BCa cells. We have previously shown using cell culture models that calcitriol acts as a selective aromatase modulator SAM and inhibits estrogen synthesis and signaling in BCa cells. We have now examined calcitriol effects in vivo on aromatase expression, estrogen signaling, and tumor growth when used alone and in combination with aromatase inhibitors AIs. At the suboptimal doses tested, anastrozole and letrozole also caused significant tumor shrinkage when used individually. Although the combinations of calcitriol and the AIs caused a statistically significant increase in tumor inhibition in comparison to the single agents, the cooperative interaction between these agents appeared to be minimal at the doses tested. Calcitriol decreased aromatase expression in the xenograft tumors.
The role of vitamin D in reducing cancer risk and progression
Effects of High Dose Calcitriol in Breast Cancer Patients - Full Text View - cprc.info
The active vitamin D metabolite, calcitriol, and astemizole, a promising antineoplastic drug, target EAG1 by inhibiting its expression and blocking ion currents, respectively. We have previously shown a synergistic antiproliferative effect of calcitriol and astemizole in breast cancer cells in vitro , but the effect of this dual therapy in vivo has not been studied. In the present study, we explored the combined antineoplastic effect of both drugs in vivo using mice xenografted with the human breast cancer cell line TD and a primary breast cancer-derived cell culture MBCDF. Tumor sizes were measured thrice weekly. The expression of Ki and the relative tumor volume were used as indicators of therapeutic efficacy. In addition, the combined therapy significantly downregulated tumoral EAG1 and Ki expression. The concomitant administration of calcitriol and astemizole inhibited tumor growth more efficiently than each drug alone, which may be explained by the blocking of EAG1.
Effects of High Dose Calcitriol in Breast Cancer Patients
Metrics details. In normal and neoplastic cells, growth-promoting, proangiogenic, cytotoxic and pro-apoptotic effects have all been attributed to cathelicidin antimicrobial peptide CAMP. Nevertheless, little is known about the factors regulating this peptide expression in breast cancer. Herein we asked if the well-known antineoplastic hormone calcitriol could differentially modulate CAMP gene expression in human breast cancer cells depending on the cell phenotype in terms of efficacy and potency.
NEW YORK-In patients with androgen-independent prostate cancer, a pulsed regimen of docetaxel Taxotere plus high-dose calcitriol is well tolerated and results in disease response by a variety of standard measures, according to results of a phase II trial. The findings are the latest to suggest a potential role in prostate cancer for calcitriol, the biologically active form of vitamin D. Preclinically, calcitriol has been shown to downregulate apoptosis inhibitors, induce cell cycle arrest and differentiation, and inhibit proliferation of multiple prostate cancer cell lines, including PC-3 and LNCaP. In these cell lines, calcitriol at concentrations of 0.