VITAMIN D3



Table of Contents
image Effects of potent vitamin D3 analogs on clonal proliferation of human prostate cancer cell lines
image 1,25-Dihydroxyvitamin D3 and 9-cis-retinoic acid act synergistically to inhibit the growthcause accumulation of cells in G1
image Effects of 1,25 dihydroxyvitamin D3 and its analogues on induction of apoptosis in breast cancer cells
image Vitamin D receptor expression is required for growth modulation by 1alpha,25-dihydroxyvitamin D3 in the human prostatic carcinoma cell line ALVA-31
image Induction of transforming growth factor-beta autocrine activity by all-trans-retinoic acid and 1alpha,25-dihydroxyvitamin D3 in NRP-152 rat prostatic epithelial cells
image The 16-ene vitamin D analogs
image Control of LNCaP proliferation and differentiation: Actions and interactions of androgens, 1alpha,25-dihydroxycholecalciferol, all-trans retinoid acid, 9-cis retinoic acid, and phenylacetate
image 1,25-Dihydroxy-16-ene-23-yne-vitamin D3 and prostate cancer cell proliferation in vivo
image Actions of vitamin D3 analogs on human prostate cancer cell lines: Comparison with 1,25-dihydroxyvitamin D3
image Human prostate cancer cells: Inhibition of proliferation by vitamin D analogs
image Vitamin D and prostate cancer: 1,25 Dihydroxyvitamin D3 receptors and actions in human prostate cancer cell lines
image Combined therapy with salmon calcitonin and high doses of active vitamin D3 metabolites in uremic hyperparathyroidism
image 24,25 dihydroxyvitamin D supplementation corrects hyperparathyroidism and improves skeletal abnormalities in X-linked hypophosphatemic rickets - A clinical research center study
image 1-alpha-hydroxyvitamin D3 treatment decreases bone turnover and modulates calcium-regulating hormones in early postmenopausal women
image Oral vitamin D or calcium carbonate in the prevention of renal bone disease?
image 24,25 dihydroxyvitamin D supplementation corrects Intradialytic calcium balances with different calcium dialysate levels. Effects on cardiovascular stability and parathyroid function
image Biochemical effects of calcium and vitamin D supplementation in elderly, institutionalized, vitamin D-deficient patients
image Calcium, phosphate, vitamin D, and the parathyroid
image Determinants for serum 1,25-dihydroxycholecalciferol in primary hyperparathyroidism
image Treatment with active vitamin D (alphacalcidol) in patients with mild primary hyperparathyroidism
image The effect of 1,25(OH)2 vitamin D3 on CD4+/CD8+ subsets of T lymphocytes in postmenopausal women
image 1-alpha-hydroxyvitamin D3 treatment decreases bone turnover and modulates calcium-regulating hormones in early postmenopausal women
image Amelioration of hemiplegia-associated osteopenia more than 4 years after stroke by 1alpha-hydroxyvitamin D3 and calcium supplementation
image Effect of 1,25(OH)2 vitamin D3 on circulating insulin-like growth factor-I and beta2 microglobulin in patients with osteoporosis
image Increased catabolism of 25-hydroxyvitamin D in patients with partial gastrectomy and elevated 1,25-dihydroxyvitamin D levels. Implications for metabolic bone disease
image The effect of season and latitude on in vitro vitamin D formation by sunlight in South Africa
image Effects of 2 years' treatment of osteoporosis with 1alpha-hydroxy vitamin D3 on bone mineral density and incidence of fracture: A placebo-controlled, double-blind prospective study
image 1,25-Dihydroxyvitamin D3 enhances the enzymatic activity and expression of the messenger ribonucleic acid for aromatase cytochrome P450 synergistically with dexamethasone depending on the vitamin D receptor level in cultured human osteoblasts
image 1,25-dihydroxyvitamin D3 reversibly blocks the progression of relapsing encephalomyelitis, a model of multiple sclerosis
image All-trans and 9-cis retinoic acid enhance 1,25-dihydroxyvitamin D3-induced monocytic differentiation of U937 cells.
image Expression of Retinoid X Receptor alpha is increased upon monocytic cell differentiation.
image Combination of a potent 20-epi-vitamin D3 analogue (KH 1060) with 9- cis-retinoic acid irreversibly inhibits clonal growth, decreases bcl-2 expression, and induces apoptosis in HL-60 leukemic cells
image Monocytic differentiation modulates apoptotic response to cytotoxic anti-Fas antibody and tumor necrosis factor alpha in human monoblast U937 cells
image Myeloma cell growth arrest, apoptosis, and interleukin-6 receptor modulation induced by EB1089, a vitamin D3 derivative, alone or in association with dexamethasone
image Mutation in the ligand-binding domain of the retinoic acid receptor alpha in HL-60 leukemic cells resistant to retinoic acid and with increased sensitivity to vitamin D3 analogs
image 1,25-dihydroxyvitamin D3 primes acute promyelocytic cells for TPA-induced monocytic differentiation through both PKC and tyrosine phosphorylation cascades.
image [Synthesis of retinoids with a modified polar group and their antitumor activity. Report I]
image Induction of differentiation in murine erythroleukemia cells by 1 alpha,25-dihydroxy vitamin D3.
image Synergistic differentiation of U937 cells by all-trans retinoic acid and 1 alpha, 25-dihydroxyvitamin D3 is associated with the expression of retinoid X receptor alpha.
image 1,25(OH)2-16ene-vitamin D3 is a potent antileukemic agent with low potential to cause hypercalcemia.
image Inhibition of breast cancer cell growth by combined treatment with vitamin D3 analogues and tamoxifen.
image The anti-proliferative effect of vitamin D3 analogues is not mediated by inhibition of the AP-1 pathway, but may be related to promoter selectivity.
image 1,25(OH)2 vitamin D3, and retinoic acid antagonize endothelin-stimulated hypertrophy of neonatal rat cardiac myocytes.
image Inhibitory effect of 220-oxa-1,25-dihydroxyvitamin D3 on the proliferation of pancreatic cancer cell lines.
image Antiproliferative responses to two human colon cancer cell lines to vitamin D3 are differently modified by 9-cis-retinoic acid.
image Vitamin D: a modulator of cell proliferation and differentiation
image Vitamin D3 analogs inhibit growth and induce differentiation in LA-N-5 human neuroblastoma cells

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Effects of potent vitamin D3 analogs on clonal proliferation of human prostate cancer cell lines

Prostate (USA), 1997, 31/2 (77-83)

BACKGROUND. Management of prostate cancer that has spread outside of the prostate capsule is a difficult problem. Innovative, non-toxic approaches to the disease are required. New, relatively non-toxic vitamin D3 analogs have recently been synthesized. We report that several of these compounds have marked antiproliferative effects on prostate cells. METHODS. The clonal antiproliferative activity of five novel analogs of 1,25 dihydroxyvitamin D3 (1,25(OH)2D3, (cmpd C)) as well as 1,25(OH)2D3 itself was tested on three human prostate cancer cell lines (PC-3, LNCaP, and DU-145). The analogs were 20-epi-22oxa-24a, 26a, 27a-tri-homo- 1alpha,25(OH)2D3 (code name: KH 1060); 24a26a27a-tri-homo-22, 24-diene- 1alpha,25(OH)2D3 (code name: EB 1089); 1,25(OH)2-16ene-D3 (code name: HM); 1,25(OH)2-16ene-23yne-D3 (code name: V); 1,25(OH)2-20-epi-D3 (code name: MC 1288)). RESULTS. With the parent compound (1,25(OH)2D3), the effective dose that inhibited 50% clonogenic growth of PC-3 and LNCaP was 10-8M and 7 x 10-9 M, respectively. For these prostate cancer cell lines, KH 1060 was the most potent analog by an order of 25- to 35-fold as compared to cmpd C. The second and third most potent analogs were HM and MC 1288. DU-145 was resistant to all the vitamin D3 analogs. The major side-effect of 1,25(OH)2D3 is the production of hypercalcemia. The relative inhibitory index (RII) was determined by comparing the antiproliferative activity of the analog to its ability to produce hypercalcemia in mice injected intraperitoneally every other day. The KH 1060 had the best RTI: 50- to 70- fold greater than 1,25(OH)2D3 for PC-3 and LNCaP, respectively. CONCLUSIONS. A trial of one or more of theatment of minimal residual disease of prostate cancer.



1,25-Dihydroxyvitamin D3 and 9-cis-retinoic acid act synergistically to inhibit the growthcause accumulation of cells in G1

Endocrinology (USA), 1997, 138/4 (1491-1497)

Recent studies have suggested that the active metabolite of vitamin D3, 1,25-dihydroxyvitamin D3, can inhibit the growth and/or induce the differentiation of a variety of cell types and that these characteristics might be useful in the treatment of some cancers. Retinoids also promote the differentiation and inhibit the growth of some cells. That the vitamin D receptor acts as a heterodimer with the retinoid X receptor (RXR) suggests that there may be functional interactions between 1,25-dihydroxyvitamin D3 and retinoids. In this study, we show that the combination of 1,25- dihydroxyvitamin D3 and 9-cis retinoic acid synergistically inhibits the growth of LNCaP prostate cancer cells. That this effect is mediated by RXR rather than retinoic acid receptors was shown using RXR- and retinoic acid receptor-specific ligands. The vitamin D3 analog, EB1089, inhibited growth more effectively than 1,25-dihydroxyvitamin D3 and also acted synergistically with 9-cis-retinoic acid. These treatments caused cells to accumulate in the G1 phase of the cell cycle, suggesting that 1,25- dihydroxyvitamin D3 can regulate one or more factors critical for the G1/S transition.



Effects of 1,25 dihydroxyvitamin D3 and its analogues on induction of apoptosis in breast cancer cells

Journal of Steroid Biochemistry and Molecular Biology (United Kingdom), 1996, 58/4 (395-401)

Vitamin D derivatives have been shown both to inhibit the proliferation of cultured breast cancer cells and totumours in vivo. We have investig ated the ability of several vitamin D analogues to promote the regression of experimental rat mammary tumours. Our results revealed that one vitamin D compound in particular, EB1089 (1(S),3(R)-dihydroxy-20(R)-5'-ethyl-5'-hydroxy-hepta- 1',3'(E)-dien- 1'-yl)-9,10-secopregna-5(Z),7(E), 10(19)-triene), was highly effective at inhibiting tumour progression, without causing a significant rise in serum calcium concentration. Tumour regression occurs when the rate of cell. death is greater than the rate of cell proliferation. Apoptosis (programmed or active cell death) is an active, energy-dependent process in which a distinct series of biochemical and molecular events leads to the death of cells by specific signals. We have examined effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and the synthetic vitamin D analogue EB1089 on indices of apoptosis in cultured human breast cancer cells. The effects of the vitamin D compounds on the expression of two oncoproteins which may regulate apoptosis, bcl-2 and p53 were examined by Western analysis. In MCF-7 cell cultures treated for six days with 1,25(OH)2D3 or EB1089 (1 x 10-8 M), bcl-2 protein was reduced in comparison to control levels, whereas p53 protein was increased. In addition, the p21 protein, whose gene WAF-1 is induced by wild type p53, was also increased by both vitamin D compounds. Using Northern analysis, it was observed that 24-h treatment of MCF-7 cells with 1 x 10-8 M 1,25(OH)2D3 or EB1089 resulted in an induction of TRPM-2 (clusterin) mRNA, a gene associated with onset of apoptosis in the involuting prostate. Fragmentation of genomic DNA is a characteristic feature of apoptosis. With the terminal deoxynucleotidyl transferase (TdT) assay, 3'-OH DNA breaks indicative of DNA fragmentation were detected histochemically in MCF-7 cells treated with 1 x 10-8 M 1,25(OH)2D3 or EB1089 for four days prior to fixation and TdT reaction. Further evidence of apoptosis was obtained following six days treatment of MCF-7 cell cultures with 5 x 10-8 M 1,25(OH)2D3 or EB1089, utilizing a cell death ELISA assay, which measures the presence of histone-associated oligonucleosome complexes generated from DNA fragmentation. Taken together our findings indicate that vitamin D derivatives may play a role in regulating the expression of genes and protein products implicated in apoptosis.

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Vitamin D receptor expression is required for growth modulation by 1alpha,25-dihydroxyvitamin D3 in the human prostatic carcinoma cell line ALVA-31

Journal of Steroid Biochemistry and Molecular Biology (United Kingdom), 1996, 58/3 (277-288)

Epidemiological data suggest that vitamin D3, obtained from dietary sources and sunlight exposure, protects against mortality from prostate cancer (PC). In agreement with this, the most active vitamin D metabolite 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2 D3) regulates the growth and differentiation of several human PC cell lines. Both genomic and non-genomic signalling pathways for 1,25(OH)2 D3 have been reported, although the mechanism of action in PC cells has not been defined. We now provide data supporting an active role for the nuclear vitamin D receptor (VDe growth-inhibitory effects of 1,25(OH)2 D3 on these cells. In the VDR-rich cell line ALVA-31, the observed changes in growth by 1,25(OH)2 D3 are preceded by significant changes in VDR mRNA expression, In contrast, the cell line JCA-1, containing few VDRs, fails to show both early changes in VDR gene expression and later changes in growth with 1,25(OH)2 D3. To assess the role of the VDR more directly, transfection studies were pursued. ALVA-31 cells were stably transfected with an antisense VDR cDNA construct in an attempt to reduce VDR expression. Antisense mRNA expression among clones was associated with: (a) reduced or abolished sensitivity to the effects of 1,25(OH)2 D3 on growth; (b) decreased numbers of VDRs per cell, as measured by radiolabelled-ligand binding; and (c) a lack of induction of the VDR-regulated enzyme 24-hydroxylase in response to 1,25(OH)2 D3. From these studies we conclude that the antiproliferative effects of 1,25(OH)2 D3 require expression of the nuclear VDR in this system.



Induction of transforming growth factor-beta autocrine activity by all-trans-retinoic acid and 1alpha,25-dihydroxyvitamin D3 in NRP-152 rat prostatic epithelial cells

Journal of Cellular Physiology (USA), 1996, 166/1 (231-239)

Retinoids and vitamin D analogues are known to inhibit the proliferation of a variety of cells in culture and prevent the formation of certain tumors in mammals. Although it is well established that these hormones control the transcription of many genes upon binding to and activating specific nuclear receptors, the mechanisms by which they prevent cancer are as yet poorly understood. In this study the role of the transforming growth factor-p (TGF-beta) growth inhibitors, in promoting the biological activities of all-trans-retinoic acid (RA) and 1alpha,25-dihydroxyvitamin D3 (1,25-(OH)2D3) was studied in NRP-152 cells, a nontumorigenic epithelial line derived from rat dorsal-lateral prostate. Inhibition of growth by nanomolar concentrations of RA was associated with an increase in both mRNA and protein for all three TGF-beta isoforms, with greater and much earlier increases for TGF-betas 2 and 3 (5.5 h) than for TGF-beta1 (24 h). A monoclonal antibody against TGF-beta and TGF-beta1 latency associated peptide (LAP), both of which neutralize all three TGF-beta isoforms, each block the ability of RA to inhibit growth of NRP-152 cells by >95%. Neutralization of growth inhibition by isoform-specific antibodies suggested that all three TGF-betas are involved in this effect. The ability of RA to upregulate fibronectin and thrombospondin expression in NRP-152 cells was also blocked by the monoclonal antibody. 1,25-(OH)2D3, which also induced TCF-betas 2 and 3 but not TGF-beta1, and their respective mRNAs, also induced fibronectin and thrombospondin through induction of TGF-beta. Thus, autocrine production of TGF-betas may be a significant part of the mechanisms by which RA and 1,25-(OH)2D3 promote cellular differentiation.



The 16-ene vitamin D analogs

Current Pharmaceutical Design (Netherlands), 1997, 3/1 (99-123)

Numerous 16-ene vitamin D analogs were investigated as potential anticancer agents. Several structural modifications have been uncovered that contribute to the improvement in the stimulation of HL-60 cells differentiation, the inhibition of HL-60 cells proliferation and the reduction of calcemic properties in vivo. They include the introduction of 16-, 22E-, 23E- and 23Z-double bonds, 23-triple bond or 22R-allene, and substitution of C26 and C27-hydrogens with fluorine or methyl groups. The biggest gains have been achieved by combination of the 16-double bond with 23-double or triple bond and 26-trifluoro or 26,27-hexafluoro substitution patterns. Separately, the combination of the 16-double bond with 22R-allene has produced a highly active analog. In respect to modifications in the ring A, the high activities in cell differentiation and inhibition of cell proliferation with significant reduction of calcemic properties were observed in the 1alpha-fluoro, 3-desoxy, and 19-nor series. It was also shown that the lack of the 1alpha-hydroxy group can be overcome by an optimized modification in the ring D and the side chain; 25(OH)-16,23E-diene-26,27-F6D3 is fully active in HL-60 cell differentiation assay with only mimimal effects on the cellular calcium homeostasis.



Control of LNCaP proliferation and differentiation: Actions and interactions of androgens, 1alpha,25-dihydroxycholecalciferol, all-trans retinoid acid, 9-cis retinoic acid, and phenylacetate

Prostate (USA), 1996, 28/3 (182-194)

There is increasing evidence that growth and differentiation of prostatic carcinoma cells may be modulated not only by androgens and growth factors but also by vitamin D, retinoids, and phenylacetate (PA). The latter agonists may have a role in the prevention and therapy of prostate cancer but their exact therapeutic potential remains unclear. Since both retinoids and vitamin D act via nuclear receptors, the same way androgens do, we studied the interactions of these compounds with androgen-induced proliferation and differentiation using LNCaP cells as a model of androgen-responsive tumor cells. PA was included because of its suspected different mode of action. (3H)-thymidine incorporation was used as a measure of proliferative activity, secretion of prostate-specific antigen (PSA) as a measure of differentiated function. The present data show that 1alpha,25-dihydroxycholecalciferol (VD3), all-trans retinoic acid (atRA), 9-cis retinoic acid (9cRA), and PA stimulated LNCaP cell-differentiated function in the presence or absence of androgens. The effects on cell growth were more complicated. In the absence of androgens growth stimulatory effects were observed for the retinoids and under some conditions for VD3. These effects were limited, however, and tended to be more pronounced at low cell densities. In the presence of androgens nearly exclusively growth inhibitory effects were observed. On a molar basis VD3 was the most effective antiproliferative agonist (ED50 = 10-9 M). It completely neutralized the stimulatory effects of androgens. Growth inhibition was not due to a decrease in the concentration of androgen receptor: whereas atRA, 9cRA, and PA did not alter androgen receptor levels, VD3 provoked a twofold increase. Neither in the presence nor in the absence of androgens did we observe any cooperativity in the growth stimulatory or inhibitory effects of VD3, atRA, or 9cRA. To test whether treatment with any of the studied agonists resulted in a phenotypic reversion and sustained growth arrest, LNCaP cells were pretreated with VD3, atRA, 9cRA, or PA for 6-12 days and reseeded at equal densities as untreated cells. In all cases tested (3H)-thymidine incorporation was restored within 6 days suggesting that none of these compounds caused irreversible growth inhibition.



1,25-Dihydroxy-16-ene-23-yne-vitamin D3 and prostate cancer cell proliferation in vivo

Urology (USA), 1995, 46/3 (365-369)

Objectives. 1,25-Dihydroxyvitamin D can inhibit the proliferation of prostate cancer cells, but its clinical use is limited by hypercalcemia. We examined the effects of a 'noncalcemic' vitamin D analogue, 1,25-Dihydroxy- 16-ene-23-yne-cholecalciferol (16-23-D3), on the proliferation of human prostate cancer cells in a mouse model. Methods. Twenty-four athymic nude mice were inoculated with human prostate carcinoma cells from the PC-3 cell line. Twelve mice (experimental group) received injections of 1.6 microg of 16- 23-D3 on alternate days over a 22-day period. Twelve mice (control group) received sham injections. Tumor volumes, pathologic findings, and terminal serum calcium levels were compared between groups. Results. The relative increase in tumor volume was significantly lower in the experimental than in the control group in the first interval following treatment (P < 0.01). Mean tumor volumes in the experimental group were approximately 15% smaller than in the control group. Serum calcium levels did not differ between groups. Conclusions. 16-23-D3 showed modest antiproliferative effects on prostate cancer cells in this model without evidence of drug-induced hypercalcemia. These findings support the concept that vitamin D analogues can inhibit the proliferation of human prostate cancer cells in vivo.



Actions of vitamin D3 analogs on human prostate cancer cell lines: Comparison with 1,25-dihydroxyvitamin D3

ENDOCRINOLOGY (USA), 1995, 136/1 (20-26)

Data from epidemiological studies has suggested that vitamin D deficiency may promote prostate cancer, although the mechanism is not understood. We have previously demonstrated the presence of vitamin D receptors (VDR) in three human prostate carcinoma cell lines (LNCaP, PC-3, and DU-145) as well as in primary cultures of stromal and epithelial cells derived from normal and malignant prostate tissues. We have also shown that 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) can elicit an antiproliferative action in these cells. In the present study we compared the biological actions of 1,25-(OH)2D3 to those of a series of natural vitamin D3 metabolites and several synthetic analogs of vitamin D3 known to exhibit less hypercalcemic activity in vivo. In ligand binding competition experiments, we demonstrated the following order of potency in displacing (3H)1,25(OH)2D3 from VDR: EB-1089 > 1,25- (OH)2D3 > MC-903 > 1,24,25(OH)3D3 > 22-oxacalcitriol (OCT) > 1alpha,25- dihydroxy-16-ene-cholecalc iferol (Ro24-2637) > 25-hydroxyvitamin D3, with EB-1089 being similar2-fold more potent than the native hormone. No competitive activity was found for 25-hydroxy-16,23-diene-cholecalciferol. When compared for ability to inhibit proliferation of LNCaP cells, MC-903, EB-1089, OCT, and Ro24-2637 exhibited 4-, 3-, 3-, and 2-fold greater inhibitory activity than 1,25-(OH)2D3. Interestingly, although OCT and Ro24-2637 exhibit, respectively, 10 and 14 times lower affinity for VDR than 1,25-(OH)2D3, both compounds inhibited the proliferation of LNCaP cells with a potency greater than that of the native hormone. The relative potency of vitamin D2 metabolites and analogs to inhibit cell proliferation correlated well with the ability of these compounds to stimulate prostate-specific antigen secretion by LNCaP cells as well as with their potency to induce the 25- hydroxyvitamin D3-24-hydroxylase messenger RNA transcript in PC-3 cells. In conclusion, these results demonstrate that synthetic analogs of vitamin D3, known to exhibit reduced calcemic activity, can elicit antiproliferative effects and other biological actions in LNCaP and PC-3 cell lines. It is noteworthy that although binding to VDR is critical for 1,25-(OH)2D3 action, the analog data indicate that additional factors significantly contribute to the magnitude of the biological response. Finally, the strong antiproliferative effects of several synthetic analogs known to exhibit less calcemic activity than 1,25(OH)2D3 suggest that these compounds potentially may be useful as an additional therapeutic option for the treatment of prostate cancer.



Human prostate cancer cells: Inhibition of proliferation by vitamin D analogs

ANTICANCER RES. (Greece), 1994, 14/3 A (1077-1081)

1,25-Dihydroxyvitamin D (1,25(0H)2D3, calcitriol) can inhibit the proliferation of some human prostate cancer cells but its clinical use is limited by hypercalcemia. We therefore explored the bioactivity of less calcemic vitamin D analogs. We studied the effects of calcitriol and 3 synthetic analogs at concentrations of 10-6 to 10-12 M on the in vitro proliferation of 3 human prostate carcinoma cell lines: DU 145, PC-3, and LNCaP. Calcitriol and analogs showed significant antiproliferative activity on PC-3 and LNCaP cells. DU 145 cells were inhibited by the analogs only. We conclude that vitamin D analogs warrant further investigation as therapeutic agents in prostate cancer.



Vitamin D and prostate cancer: 1,25 Dihydroxyvitamin D3 receptors and actions in human prostate cancer cell lines

ENDOCRINOLOGY (USA), 1993, 132/5 (1952-1960)

It has been suggested that vitamin D deficiency may promote prostate cancer, although the mechanism is not understood. In this study three human prostate carcinoma cell lines, LNCaP, DU-145, and PC-3, were examined both for the presence of specific 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) receptors (VDRs) and also employed to study the effects of hormone on cell proliferation and differentiation. Ligand binding experiments demonstrated classical VDR in all three cell lines examined with an apparent dissociation constant of 7.5, 5.4, and 6.3 x 10-11 M for LNCaP, DU-145, and PC-3 cells, respectively. Corresponding binding capacity for the three prostate carcinoma cell lines were 27, 31, and 78 fmol/mg protein, respectively. The presence of VDR in the three cell lines was also confirmed by immunocytochemistry. In addition, one major 4.6-kilobase messenger RNA transcript hybridizing with a specific human VDR complementary DNA probe was identified in all three cell lines. Interestingly, both DU-145 and PC-3 but not LNCaP cell lines exhibited 1,25(OH)2D3-stimulated induction of 24-hydroxylase messenger RNA employed as a marker of 1,25(OH)2D3 action. Physiological levels of 1,25(OH)2D3 dramatically inhibited proliferation of the LNCaP and PC-3 cell lines. However, in spite of the presence of high affinity VDR, proliferation of DU- 145 cells was not inhibited by 1,25(OH)2D3 at the doses tested. Treatment with 1,25(OH)2D3 caused a dose-dependent stimulation of prostate-specific antigen secretion by LNCaP cells. In conclusion, these results demonstrate that these three human prostate carcinoma cell lines all possess specific VDR and that 1,25(OH)2D3 treatment can elicit both an antiproliferative and a differentiating action on these cancer cells. The findings lend support to the hypothesis that vitamin D might exert beneficial actions on prostate cancer risk.



Combined therapy with salmon calcitonin and high doses of active vitamin D3 metabolites in uremic hyperparathyroidism

Polskie Archiwum Medycyny Wewnetrznej (Poland), 1996, 96/1 (23-31)

Active vitamin D3 pulse therapy effectively suppress parathormon (PTH) synthesis in uremic hyperparathyroidism but high serum levels of calcitriol achieved can induce direct osteoclastic resorption and block bone formation. Therefore we found it interesting to examine whether an addition of the osteoclast inhibitor, calcitonin (CT), could reduce those unwanted effects. 75 hemodialysis patients with at least 5-fold 1-84 PTH serum level elevation were divided into 4 treatment groups; I (n = 19) - CT and 1alpha-OH-D3; II (n = 20) - CT; III (n = 19) - 1alpha-OH-D3 (n = 10) or 1,25(OH)2D3 (n = 9) alone; IV (n = 17) - none of these drugs. CT (200 IU) and 1alpha-OH-D3/1,25(OH2D3 (up to 5 microg) were given 3 times a week. Dialysate Ca was 1.40-1.45 (Group I, III) or 1.95-2.00 mmol/l (Group II, IV). Within 8 months serum 1-84 PTH fell by 75% (p&lt0.001) in Group I and by 77% (p&lt0.001) in Group II, serum Ca increased by 0.22 plus or minus 0.05 mmol/l in Group I (p&lt0.005) and by 0.25 plus or minus 0.05 mmol/l in Group III (p&lt0.005), alkaline phosphatase activity decreased by 35% in Group I (p&lt0.01) and 31% in Group III (p&lt0.005) whereas in Groups II and IV no significant changes were noted. In Group III no differences between patients taking 1alpha-OH-D3 or 1,25(OH)2D3 were observed. The significant reduction of serum hydroxyproline (37%, p&lt0.001) was seen only in Group I. The increase in bone mineral density (BMD) measured by dual-energy X-ray absorptiometry was greater in Group I than in Group III (p&lt0.05). In Group II the effect was mostly insignificant, whereas in Group IV a substantial decrease (p&lt0.001) in BMD was observed. These data suggest that combined therapy with CT and oral 1alpha-OH-D3 pulses is more effective than pulses alone in inhibiting bone resorption and in increasing BMD in hemodialysis patients with uremic hyperparathyroid bone disease.



24,25 dihydroxyvitamin D supplementation corrects hyperparathyroidism and improves skeletal abnormalities in X-linked hypophosphatemic rickets - A clinical research center study

Journal of Clinical Endocrinology and Metabolism (USA), 1996, 81/6 (2381-2388)

Therapy for X-linked hypophosphatemia (XLH) only partially corrects skeletal lesions and is often complicated by hyperparathyroidism. 24,25(OH)2 D3 improves skeletal lesions in a murine model of XLH and suppresses PTH secretion in animals. Therefore, we undertook a placebo-controlled trial of 24,25(OH)2 D3 supplementation to standard treatment in patients with XLH to improve bone disease and reduce hyperparathyroid complications. Fifteen subjects with XLH receiving standard treatment (1,25(OH)2 D3 or dihydrotachysterol plus phosphate) were evaluated, supplemented with placebo, and reevaluated one yr later. 24,25(OH)2 D3 supplementation was then begun and studies repeated after another year. Each patient underwent a detailed evaluation of calcium homeostasis over a 24-h period. Rachitic abnormalities were assessed radiographically in children. Adults underwent bone biopsies. 24,25(OH)2 D3 normalized PTH values in nine subjects (peak PTH was 46.5 plus or minus 6.6 pmol/L at entry, 42.3 plus or minus 5.9 pmol/L after placebo, and 23.3 plus or minus 5.4 pmol/L after 24,25(OH)2 D3). Nephrogenous cAMP decreased at night, coincident with the decrease in PTH, and serum phosphorus was slightly greater with 24,25(OH)2 D3. Radiographic features of rickets improved during 24,25(OH)2 D3 supplementation in children, and osteoid surface decreased in adults. 24,25(OH)2 D3 is a useful adjunct to standard therapy in XLH by effecting correction of hyperparathyroidism and improvement of rickets and osteomalacia.



1-alpha-hydroxyvitamin D3 treatment decreases bone turnover and modulates calcium-regulating hormones in early postmenopausal women

Bone (USA), 1997, 20/6 (557-562)

50 Japanese women within 10 years after menopause (mean age 52.5 years) were studied to determine the effects of 0.75 microg of 1-alpha-hydroxyvitamin D3 (1-alpha-(OH)D3) with calcium (150 mg/day) (treated group: N = 25) and calcium only (control group: N = 25) for 12 months on bone mass and metabolism. Their L2-4 BMD measurements were 1.5 SD below the mean value of Japanese young, normal women, L2-4 BMDs increased significantly in the treated group (+2.1%; p < 0.01), but decreased significantly in controls (-2.l%; p < 0.01). Although serum calcium and creatinine remained unchanged in both groups, phosphorus levels increased significantly in the treated group (p < 0.01). Urinary calcium/creatinine (Cr) increased in both groups. Urinary pyridinoline/Cr and deoxypyridinoline/Cr decreased significantly in the treated group (p < 0.05), but not in the control group. Serum osteocalcin levels remained unchanged in both groups, Intact parathyroid hormone levels decreased significantly (p < 0.05) and calcitonin levels significantly increased in the treated group (p < 0.05), but these changes were not observed in the control group. These data clearly demonstrate that 0.75 microg of 1-alpha-(OH)D3 maintained bone mass by reducing bone resorption by modulation of calcium-regulating hormones. Temporarily increased urinary calcium excretion was observed in control group, but did not appear to be effective in modulating bone turnover.



Oral vitamin D or calcium carbonate in the prevention of renal bone disease?

Current Opinion in Nephrology and Hypertension

It is well known that hyperparathyroidism begins early in renal failure and progresses, probably not linearly, throughout the natural course of renal diseases and dialysis therapy. Recent progress in basic medical science has improved our understanding of the mechanisms by which the classically known stimuli for parathyroid hormone synthesis and secretion may act, including hypocalcaemia, hyperphosphataemia and vitamin D3 metabolism disturbances. In the treatment of hyperparathyroidism, although some authors stress the benefit of treating one of these stimuli, it is probably more effective to combine the treatment of them all. There is conclusive recent work showing the efficacy of using both CaCO3 and vitamin D3, either in chronic renal failure or in dialsis patients at every stage of hyperparathyroidism. Therefore, the treatment of hyperparathyroidism should start early, long before dialysis, and it should aim to correct any of the causal factors. Both CaCO3 and vitamin D3 derivatives may be used in the prevention and treatment of renal bone disease. The limits of this association are the increasingly often reported adynamic bone disease, which in our experience has not yet given major clinical problems, and hyperphosphataemia. Uncontrolled serum phosphate levels would counterbalance the beneficial effect of vitamin D3 derivatives on hyperparathyroidism.



24,25 dihydroxyvitamin D supplementation corrects Intradialytic calcium balances with different calcium dialysate levels. Effects on cardiovascular stability and parathyroid function

Nephron (Switzerland), 1996, 72/4 (530-535)

It has been shown that calcium carbonate (CaCO3) is an effective phosphate binder which is less toxic than Al(OH)3. However, given that its use with standard calcium dialysate (CaD) levels may lead to hypercalcemia, a decrease in CaD levels has been proposed. The aim of the present study was to evaluate the acute clinical and biochemical consequences of a lowering of CaD in HD patients. Dialysate composition was otherwise the same. (1) Blood pressure levels (BP) during short hemodialysis were measured in a group of 12 patients who underwent alternate hemodialyses with dialysate calcium of 1.75 and 1.25 mmol/l. (2) Ca2+ and PTH kinetics during short hemodialysis were studied in a group of 6 patients who were sequentially treated with 1.75 and 1.25 mmol/l CaD. The results show: (1) that cardiovascular stability in chronic HD patients during short HD sessions with low CaD (LCaD) may be good; (2) that a single treatment with standard CaD (SCaD) produces positive calcium balances (JCa2+) with Ca2+ plasma increase and PTHi inhibition at the end of HD sessions; during HD with LCaD there were neutral mean JCa2+ and no changes in post-dialysis mean Ca2+ and PTHi plasma levels; furthermore 2 patients showed a small PTHi increase during HD with LCaD and neutral JCa2+ because of a high positive bicarbonate balance during HD. In conclusion, as with several aspects of dialysis treatment, dialysate calcium levels should also be individualized to avoid hypercalcemic crises or PTHi stimulation.



Biochemical effects of calcium and vitamin D supplementation in elderly, institutionalized, vitamin D-deficient patients

Revue du Rhumatisme (English Edition) (France), 1996, 63/2 (135-140)

Forty-five subjects (41 women and 4 men) in long-stay and medium-stay facilities, aged 74 to 95 years (mean 86.4 years), with 25-hydroxy-vitamin D levels less than 12 ng/ml, were treated for six consecutive months with two tablets per day of a preparation containing vitamin D3 (800 IU/day) and calcium carbonate (1 g elemental calcium/day). Serum levels of 25-hydroxy-vitamin D were very low at baseline (5.6 plus or minus 0.4 ng/ml) and rose significantly under treatment, to normal values, 33.2 plus or minus 1.2 and 40.9 plus or minus 2.1 ng/ml after three and six months, respectively (p < 0.001 for both comparisons). Serum calcium increased significantly, by 4.5% (p < 0.001) during the first three months, and remained at a plateau thereafter. Corrected serum calcium rose by 8.9% (p < 0.001) during the trial. No patient developed hypercalcemia. Serum parathyroid hormone levels, which were elevated at baseline (71.6 plus or minus 5.8 pg/ml; normal, 12 to 54 pg/ml), decreased gradually and significantly throughout the treatment period, by 43.0% and 67.1% after three and six months, respectively (p < 0.001 for both comparisons). Serum alkaline phosphatase activity fell concomitantly, by 9.9% after three months (p < 0.01) and 36.5% after six months (p < 0.001). In conclusion, the preparation used in our study is effective in correcting both the vitamin D deficiency that is prevalent in elderly institutionalized patients and the resultant increase in bone turnover.



Calcium, phosphate, vitamin D, and the parathyroid

Pediatric Nephrology (Germany), 1996, 10/3 (364-367)

The main factors which regulate parathyroid hormone (PTH) production are calcium, phosphate, vitamin D, and estrogens. Hypocalcemia leads to increased PTH secretion in seconds and minutes, gene expression in hours, and parathyroid (PT) cell number in weeks and months. Hypercalcemia leads to a decrease in PTH secretion by its action on the PT cell calcium receptor and no decrease in PTH mRNA levels. There is now convincing evidence that phosphate regulates the PT, independent of its effect on serum calcium and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). In vivo in rats hypophosphatemia markedly decreases PTH mRNA and serum intact PTH levels, independent of its effect on serum calcium and 1,25(OH)2D3. Clinical studies also indicate that phosphate regulates the PT independent of its effect on calcium and 1,25(OH)2D3; 1,25(OH)2D3 itself has a marked effect on the PT, where it decreases PTH gene transcription by a direct action on the PT. The application of basic science findings of how calcium, phosphate, and 1,25(OH)2D3 regulate the PT has led to an efficient and safe prescription for the management of the secondary hyperparathyroidism of chronic renal failure, which is the maintenance of a normal serum calcium and phosphate and the careful use of 1,25(OH)2D3.



Determinants for serum 1,25-dihydroxycholecalciferol in primary hyperparathyroidism

BONE MINER. (Netherlands), 1989, 5/3 (279-290)

Serum levels of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) 25-hydroxyvitamin D3 (25(OH)D3), C-terminal immunoreactive PTH (iPTH), calcium and phosphate, and endogenous creatinine clearance (Cl(cr)) were measured in 34 patients with primary hyperparathyroidism. Cl(cr) ranged from 13 to 161 ml/min (mean 72). S-iPTH was elevated in 82% of the patients and correlated positively to serum calcium (r = 0.74, P&lt0.001) and inversely to Cl(cr) (r = -0.50, P&lt0.02). S-25(OH)D3 was reduced in 28% of the patients and depended on regular multivitamin supplementation (P&lt0.005). S-1,25(OH)2D3 was increased in 26% of the patients and decreased in 9%. It was positively correlated to S-25(OH)D3 (r = 0.39, P&lt0.05) and Cl(cr) (r = 0.42, P&lt0.02) and inversely to serum levels of calcium (r = -0.39, P&lt0.05), phosphate (r = -0.42, P&lt0.02) and iPTH (r = -0.40, P&lt0.05). Multiple regression analysis revealed a positive correlation to 25(OH)D3 when Cl(cr) was taken into account and to Cl(cr) when S-25(OH)D3 was taken into account. When both variables were considered no significant partial correlations were found between S-1.25(OH)2D3 and serum calcium, phosphate and PTH, respectively. It is concluded that serum levels of 25(OH)D3 and renal function are the main determinants for S-1,25(OH)2D3 in primary hyperparathyroidism.



Treatment with active vitamin D (alphacalcidol) in patients with mild primary hyperparathyroidism

ACTA ENDOCRINOL. (Denmark), 1989, 120/2 (250-256)

The parathyroid gland possesses receptors for 1,25-dihydroxyvitamin D3, the active metabolite of the vitamin D system, and in vitro experiments have shown that 1,25-dihydroxyvitamin D3 can inhibit the secretion of PTH. In this study 31 subjects who had displayed persistent mild hypercalcemia for 14 years and presumably had mild primary hyperparathyroidism (HPT) were challenged with 1.0 microg alphacalcidol (1alpha-(OH)-vitamin D3) over 6 months in a double-blind, placebo-controlled study. Before initiation of therapy, the hyperparathyroid subjects showed lower serum levels of 1,25-dihydroxyvitamin D in relation to PTH or calcium when compared with age- and sex-matched controls. Treatment induced a slight rise in serum calcium (0.05 mmol/l), but no sigificant decrease of the PTH levels. Eighteen of the subjects thereafter entered open study with a higher dose of alphacalcidol (2.0 microg) over 1 year. Although this high dose induced a marked rise in serum calcium (0.17 mmol/l), there was only a transient reduction of the PTH levels. Thus, during long-term condition there was an escape from the suppressive action of the elevated calcium concentrations and no evidence of a specific inhibition of PTH secretion by a small oral dose of active vitamin D. Eleven patients on chronic haemodialysis treatment thrice weekly received 1 microg 1,25(OH)2D3 i.v. after each dialysis for 3 weeks. Phosphate binders were mainly CaCO3, supplemented in a few patients by moderate amounts of Al(OH)3. Ionised calcium was measured by ion-selective electrode, normal values being 1.28-1.42 mmol/l. PTH was estimated by an N-terminal-sensitive assay; normal values are < 0.25 ng/ml. Results before and after 1,25(OH)2D3 were: ionised calcium before haemodialysis, 1.19 plus or minus 0.12 and 1.17 plus or minus 0.14; ionised calcium after haemodialysis, 1.33 plus or minus 0.07 and 1.30 plus or minus 0.09; PTH before haemodialysis, 1.39 plus or minus 0.71 and 1.38 plus or minus 0.69; PTH after haemodialysis, 0.64 plus or minus 0.22 and 0.60 plus or minus 0.17; phosphate before haemodialysis, 1.85 plus or minus 0.48 and 2.18 plus or minus 0.43 (P < 0.05). No change of PTH concentration and ionised calcium before and after haemodialysis treatment could be documented after i.v. 1,25(OH)2D3 treatmetn. Mild and severe hyperparathyroidism were indistinguishable. Increased serum calcium concentrations therefore appear to be required for the suppression of PTH secretion by i.v. 1,25(OH)2D3 therapy.



The effect of 1,25(OH)2 vitamin D3 on CD4+/CD8+ subsets of T lymphocytes in postmenopausal women

Life Sciences (USA), 1997, 61/2 (147-152)

The effect of exogenous 1,25(OH)2 vitamin D3 (1,25(OH)2D3) on the CD3+, CD4+ and CD8+ subsets (counts/ul) of T lymphocytes was investigated in two randomized groups of post menopausal women. Group one (16 subjects) received 1ug/day of the secosteroid for 14 days, while group two (14 participants) was treated with 2 ug/day for the same period. The placebo group comprised another 10 postmenopausal women. Compliance of the treatment was controlled by serum intact parathyroid hormone (PTH) levels, which markedly declined at the end of the treatment (p&lt0.01 for both doses). The vitamin D status of the women before the treatment was defined by serum 25(OH) vitamin D (25(OH)D) levels. The lower dose of the secosteroid did not change any of the measured immune parameters. After a higher dose of 1,25(OH)2 D3 the mean values of CD3+ and CD8+ increased (p&lt0.05 for the both parameters), but no changes in total lymphocytes and the CD4+ subset were observed. There were no correlations between the immune response DeltaCD3+, DeltaCD4+ and DeltaCD8+) and basal circulating 25(OH)D. Briefly, then, 1,25(OH)2D3 slighly but significantly increases CD3+ and CD8+ subsets independently on the initial vitamin D status of the postmenopausal women.



1-alpha-hydroxyvitamin D3 treatment decreases bone turnover and modulates calcium-regulating hormones in early postmenopausal women

Bone (USA), 1997, 20/6 (557-562)

50 Japanese women within 10 years after menopause (mean age 52.5 years) were studied to determine the effects of 0.75 microg of 1-alpha-hydroxyvitamin D3 (1-alpha-(OH)D3) with calcium (150 mg/day) (treated group: N = 25) and calcium only (control group: N = 25) for 12 months on bone mass and metabolism. Their L2-4 BMD measurements were 1.5 SD below the mean value of Japanese young, normal women, L2-4 BMDs increased significantly in the treated group (+2.1%; p < 0.01), but decreased significantly in controls (-2.l%; p < 0.01). Although serum calcium and creatinine remained unchanged in both groups, phosphorus levels increased significantly in the treated group (p < 0.01). Urinary calcium/creatinine (Cr) increased in both groups. Urinary pyridinoline/Cr and deoxypyridinoline/Cr decreased significantly in the treated group (p < 0.05), but not in the control group. Serum osteocalcin levels remained unchanged in both groups, Intact parathyroid hormone levels decreased significantly (p < 0.05) and calcitonin levels significantly increased in the treated group (p < 0.05), but these changes were not observed in the control group. These data clearly demonstrate that 0.75 microg of 1-alpha-(OH)D3 maintained bone mass by reducing bone resorption by modulation of calcium-regulating hormones. Temporarily increased urinary calcium excretion was observed in control group, but did not appear to be effective in modulating bone turnover.



Amelioration of hemiplegia-associated osteopenia more than 4 years after stroke by 1alpha-hydroxyvitamin D3 and calcium supplementation

Stroke (USA), 1997, 28/4 (736-739)

Background and Purpose: It has been demonstrated that bone mass was significantly reduced on the hemiplegic side of stroke patients, which might increase their risk of hip fracture. We evaluated the efficacy of 1alpha- hydroxyvitamin D3 (1alpha(OH)D3) and supplemental elemental calcium in maintaining bone mass and decreasing the incidence of hip fractures after hemiplegic stroke. Methods: In a randomized study, 64 patients with hemiplegia after stroke with a mean duration of illness of 4.8 years received either 1 microg 1alpha(OH)D3 daily (treatment group, n=30) or an inactive placebo (placebo group, n=34) for 6 months and were observed for this duration. Both groups received 300 mg of elemental calcium daily. The bone mineral density (BMD) and metacarpal index (MCI) in the second metacarpals were determined by computed x-ray densitometry. The incidence of hip fractures in these patients was recorded. Results: BMD on the hemiplegic side decreased by 2.4% in the treatment group and 8.9% in the placebo group (P=.0021), while BMD on the intact side increased by 3.5% and decreased by 6.3% in the treated and placebo groups, respectively (P=.0177). In the treatment group, the difference in BMD between hemiplegic and nonhemiplegic sides decreased significantly compared with that before randomization. This difference increased in the placebo group. We observed a similar improvement in MCI in the treatment group but not in the placebo group. Four patients in the placebo group suffered a hip fracture compared with none in the treatment group (P=.0362). Conclusions: Treatment with 1alpha(OH)D3 and supplemental elemental calcium can reduce the risk of hip fractures and can prevent further decreases in BMD and MCI on the hemiplegic side of patients with a long-standing stroke. Treatment also may improve these indices on the intact side.



Effect of 1,25(OH)2 vitamin D3 on circulating insulin-like growth factor-I and beta2 microglobulin in patients with osteoporosis

Calcified Tissue International (USA), 1997, 60/3 (236-239)

To test the hypothesis that growth factors mediate the stimulatory effect of 1,25(OH)2 vitamin D3 (1,25(OH)2D3) on bone remodeling in osteoporosis, the authors studied the effect of the secosteroid administration in two closes (1 microg and day and 2 microg/day) for 14 days on circulating insulin-like growth factor-I (IGF-I), beta2 microglobulin, anti osteocalcin in 18 osteoporotic women. The biological effectiveness of the treatment was controlled by a decline of serum intact parathyroid hormone. Compared with the values before treatment, 1,25(OH)2D3 increased means of plasma IGF I, beta2 microglobulin, and serum osteocalcin significantly: however, the effects were only apparent after the higher dose of the drug (169 + or - 26 versus 134 + or - 28 ng/ml, P < 0.01; 2.08 + or - 0.1 versus 1.92 plus or minus 0.1 microg/ml, P < 0.05; and 8.5 plus or minus 1.3 versus 5.4 + or - 1.1 ng/ml, P < 0.01, respectively). The authors conclude that exogenous 1,25(OH)2D3 promotes the production of IGF-I and beta2 microglobulin in osteoporotic patients in parallel to the marker of osteoblastic function, osteocalcin, which supports the tested hypothesis.