Active Forms Of Vitamin D3 Research Articles

Micro-RNAs in Response to Active Forms of Vitamin D3 in Human Leukemia and Lymphoma Cells.

Non-coding micro-RNA (miRNAs) regulate the protein expression responsible for cell growth and proliferation. miRNAs also play a role in a cancer cells’ response to drug treatment. Knowing that leukemia and lymphoma cells show different responses to active forms of vitamin D3, we decided to investigate the role of selected miRNA molecules and regulated proteins, analyzing if there is a correlation between the selected miRNAs and regulated proteins in response to two active forms of vitamin D3, calcitriol and tacalcitol. A total of nine human cell lines were analyzed: five leukemias: MV-4-1, Thp-1, HL-60, K562, and KG-1; and four lymphomas: Raji, Daudi, Jurkat, and U2932. We selected five miRNA molecules—miR-27b, miR-32, miR-125b, miR-181a, and miR-181b—and the proteins regulated by these molecules, namely, CYP24A1, Bak1, Bim, p21, p27, p53, and NF-kB. The results showed that the level of selected miRNAs correlates with the level of proteins, especially p27, Bak1, NFκB, and CYP24A1, and miR-27b and miR-125b could be responsible for the anticancer activity of active forms of vitamin D3 in human leukemia and lymphoma.

Polymorphism of VDR Gene and the Sensitivity of Human Leukemia and Lymphoma Cells to Active Forms of Vitamin D.

Simple SummaryDeveloping new therapeutic strategies is necessary for leukemias and lymphomas treatment. Therefore, the study aimed to determine the use of an active form of vitamin D3 calcitriol and its analog tacalcitol as an anticancer drug. Most of all, selecting the molecular factor responsible for the cell’s sensitivity to the tested agents. A biomarker that could be use in the future to select patients for therapy and improve survival outcomes. We examined nine cell lines and evaluated the proteins involved in the biological activity of calcitriol and tacalcitol: the classical vitamin D receptor and 1,25D3-MARRS, as well as polymorphism in the VDR gene receptor. Results showed that VDR polymorphism may predispose to response to calcitriol and tacalcitol anticancer therapy.The active forms of vitamin D3 (calcitriol and tacalcitol) coupled to the vitamin D receptor (VDR) are known to exhibit anti-cancer properties. However, not all cancer cells are sensitive to the active forms of vitamin D3 and its analogs. The study aimed to determine whether polymorphism of VDR is responsible for the sensitivity of human leukemia and lymphoma cells to calcitriol and tacalcitol. The impact of calcitriol and tacalcitol on the proliferation and morphology of nine different leukemia and lymphoma cell lines was determined. Only MV-4-11, Thp-1, and HL-60 cell lines sensitive to proliferation inhibition by calcitriol and tacalcitol showed morphology changes. Subsequently, the levels of the VDR and 1,25D3-MARRS proteins of calcitriol and tacalcitol binding receptors and the VDR receptor polymorphism in human leukemia and lymphoma cells were ascertained. Contrary to the current understanding, higher levels of VDR are not responsible for the greater sensitivity of cells to calcitriol and tacalcitol. Importantly, we first showed that sensitivity to calcitriol and tacalcitol in leukemias and lymphomas could be determined by the VDR polymorphism. The FokI polymorphism and the presence of the “bat” haplotype were observed only in the sensitive cells.

The Impact of Vitamin D on Skin Aging.

The active metabolites of vitamin D3 (D3) and lumisterol (L3) exert a variety of antiaging and photoprotective effects on the skin. These are achieved through immunomodulation and include anti-inflammatory actions, regulation of keratinocytes proliferation, and differentiation programs to build the epidermal barrier necessary for maintaining skin homeostasis. In addition, they induce antioxidative responses, inhibit DNA damage and induce DNA repair mechanisms to attenuate premature skin aging and cancerogenesis. The mechanism of action would involve interaction with multiple nuclear receptors including VDR, AhR, LXR, reverse agonism on RORα and -γ, and nongenomic actions through 1,25D3-MARRS receptor and interaction with the nongenomic binding site of the VDR. Therefore, active forms of vitamin D3 including its canonical (1,25(OH)2D3) and noncanonical (CYP11A1-intitated) D3 derivatives as well as L3 derivatives are promising agents for the prevention, attenuation, or treatment of premature skin aging. They could be administrated orally and/or topically. Other forms of parenteral application of vitamin D3 precursor should be considered to avoid its predominant metabolism to 25(OH)D3 that is not recognized by CYP11A1 enzyme. The efficacy of topically applied vitamin D3 and L3 derivatives needs further clinical evaluation in future trials.

The role of vitamin D3 in signaling pathways – potential anticancer properties of calcitriol and its analogues

Vitamin D, for many years after the discovery, primarily was associated with bone metabolic processes. Currently, many studies indicate its beneficial effect in the prevention and treatment of many diseases, including cancer. However, deficiency of vitamin D is associated with greater tendency to get sick and worse prognosis in treatment, especially cancer. Calcitriol, an active form of vitamin D (1.25(OH)2D3) and its analogues have a pleiotropic activity, including anti-cancer properties. Many studies indicate, that the active forms of vitamin D3 may show anti-proliferative effects in cancer cells by inhibiting the cell cycle, inducing differentiation or leading to apoptosis and enhancing autophagy. Also, extremely important are the possibilities of reducing the invasiveness of tumours through the influence on angiogenesis or adhesion and others. Especially, the anti-cancer role of vitamin D3 is suggested in the case of tumors whose cells express VDR receptors. Interestingly, many cancer cells not only express the VDR receptors, but also due to the expression of CYP27B1 and CYP24A hydroxylases, they can regulate metabolism of calcitriol. Many of the studies using vitamin D3 show that calcitriol and its analogues, due to the influence on cancer cells, can play promising roles in anticancer therapies. Consider the broad pleiotropism of the action of active metabolites of vitamin D3 and the development of research in this field, the current work presents the effect of active forms of vitamin D on some signalling pathways and the regulation of selected proteins in various cancers.

Differential response of lung cancer cell lines to vitamin D derivatives depending on EGFR, KRAS, p53 mutation status and VDR polymorphism

Vitamin D reveals antiproliferative activity against many types of cancer cells. Calcitriol (1,25D3), the most active form of vitamin D3, acts mainly through the vitamin D receptor, regulating the expression of target genes. Cells with reasonable expression of VDR are considered to be sensitive to antiproliferative activity of 1,25D3. However, a few alleles of the VDR gene are correlated with higher or lower response to 1,25D3 treatment. The goal of our study was to establish if cells differing in EGFR, KRAS, p53 mutation status and VDR polymorphism were sensitive to antiproliferative activity of selected vitamin D derivatives (VDDs). In our search for the lead VDD against human lung cancer cells, we selected, for this study, low calcemic analogs of active forms of vitamin D2 and D3 that had previously shown anticancer potential. The selected cell lines revealed differential response to VDDs. The highest proliferation inhibition was observed for EGFR mutant cells while a weaker response was observed for KRAS and/or p53 mutant cells. 24,24-Dihomo-1,25D3 (PRI-1890) showed the highest activity on the VDD-sensitive cell lines (A549, HCC827, NCI-H1299, and NCI-H1703). Therefore, PRI-1890 was selected as the lead VDD for further structure optimization. None of the VDDs used in this study showed antiproliferative activity against A-427 and Calu-3. VDR polymorphisms correlated inversely with sensitivity to the antiproliferative activity of VDDs since we observed less transcriptionally active form of VDR in HCC827 cells sensitive to VDD, while more transcriptionally active form was observed in NCI-H358 cells that were stimulated by VDDs to proliferate. Lack of KRAS and p53 mutations in HCC827 cells may be, therefore, responsible for the higher antiproliferative activity of VDDs, while the presence of KRAS and/or p53 mutations in other cell lines might prevent antiproliferative activity even though the VDDs were transcriptionally active as assessed on increased CYP24A1 expression. VDR gene polymorphism is not directly responsible for the sensitivity of tested cells to VDDs.

Differential Effects of 1,25D3‐MARRS Expression on Mammary Gland Growth and Development Depend on the Vitamin D3 Dose

1,25 dihydroxyvitamin D3 (1,25D3) is one of the most potent biologically active forms of vitamin D3. Primary activities include regulation of blood calcium and phosphate homeostasis and a plethora of other effects including cell growth inhibition, induction of differentiation, and anti‐cancer effects, depending on the target tissue. Most of the activities of 1,25D3 continue to be ascribed to the classic vitamin D receptor despite the identification of another membrane receptor for 1,25D3. The membrane‐associated rapid response steroid‐binding (MARRS) receptor is receiving more attention as a novel vitamin D receptor working through rapid, non‐genomic pathways. The purpose of this study was to explore the role of MARRS in the mammary gland using a conditional knockout mouse model and a vitamin D3 dietary intervention. 1,25D3‐MARRS expression was reduced in epithelial cells of mammary glands (MG) using the Cre/loxp system. Dams were weaned onto semi‐purified diets with 10,000 IU/kg, 1,000 IU/kg, or 0 IU/kg of 1,25D3 for 4 weeks before being set‐up to breed. 4th MGs were collected from 6‐week old female MMTV‐Cre mice (n=73). MGs were whole‐mounted and stained with carmine alum. Tissue growth was assessed by counting the number of terminal end buds (TEB) of alveolar branches, measuring the length of the longest ductal extension, and measuring total MG area covered ducts. Whole body weight was similar between all groups. There was a significant interaction between genotype and diet. Knockout mice on the 1,000 IU/kg diet had significantly fewer TEBs (p=0.016) and reduced ductal growth and extension (p=0.037, p=0.023 respectively) compared to controls on the same diet. Mice on the 0 IU/kg diet had similar TEB counts across all genotypes. Knockout mice on the 10,000IU/kg diet had significantly more TEBs than the other mice of the same diet (p=0.042), and more extensive growth and coverage of alveolar branches than knockouts on the 1,000 IU/kg diet. These results suggest that there is an effect of 1,25D3‐MARRS that is dependent on vitamin D3 dose. Because the dose‐response is not linear in this animal model, it suggests caution when making recommendations for vitamin D3 nutrition in animals, and possibly humans as well.Support or Funding InformationThe Natural Sciences and Engineering Research Council of Canada

Nanocapsules with Polyelectrolyte Shell as a Platform for 1,25-dihydroxyvitamin D3 Neuroprotection: Study in Organotypic Hippocampal Slices.

Calcitriol (1,25-dihydroxyvitamin D3), an active metabolite of vitamin D3, besides the role in calcium and phosphorus metabolism, plays a role in maintaining the functions of the brain. Active forms of vitamin D3 stimulate neurotrophic factors’ expression, regulate brain immune processes, and prevent neuronal damage. Therefore, a potential utility of vitamin D3 in a therapy of neurodegenerative disorders should be taken into account. On the other hand, systemic vitamin D3 treatment carries the risk of undesirable effects, e.g., hypercalcemia. Thus, 1,25-dihydroxyvitamin D3 targeting delivery by nanoparticles would be a tremendous advancement in treatment of brain disorders. Calcitriol was enclosed in emulsion-templated nanocapsules with different polymeric shells: PLL (Poly(l-lysine hydrobromide)), PLL/PGA (/Poly(l-glutamic acid)), and PLL/PGA-g-PEG (Poly(l-glutamic acid) grafted with polyethylene glycol). The average size of all synthesized nanocapsules ranged from −80 to −100 nm. Biocompatibilities of synthesized nanocarriers were examined in hippocampal organotypic cultures in basal conditions and after treatment with lipopolysaccharide (LPS) using various biochemical tests. We demonstrated that nanocapsules coated with PLL were toxic, while PLL/PGA- and PLL/PGA-g-PEG-covered ones were nontoxic and used for further experiments. Our study demonstrated that in LPS-treated hippocampal slices, both types of loaded nanoparticles have protective ability. Our findings underlined that the neuroprotective action of vitamin D3 in both free and nanoparticle forms seems to be related to the suppression of LPS-induced nitric oxide release.

Immunoregulatory effects of vitamin D3 in experimentally induced type 1 diabetes

The mechanism underlying the impairment of the function of the cellular component of the immune response and its regulation by vitamin D3 in diabetes mellitus remains incompletely characterized. The present study addresses the specific features of the functioning of the T-cell link of immune response and the humoral response to injecyion of an artificial antigen in a diabetes model and after prolonged administration of vitamin D3. Chronic hyperglycemia occurring in diabetes induced a 2.3-fold decrease of the content of the marker substance 25OHD3, the major precursor of hormonally active forms of vitamin D3, in the serum. The development of vitamin D3 deficiency is accompanied by an impairment of the proliferative activity of T cells and a change in relative numbers of regulatory (CD4+) and cytotoxic (CD8+) lymphocytes. An increase of the content of the phosphorylated p65 subunit of the nuclear factor κB and more intensive translocation of this protein to the nucleus were detected in total lysates of T lymphocytes from the spleen. Moreover, enhancement of the humoral IgG response to intraperitoneal administration of a recombinant B subunit of diphtheria toxin was demonstrated. Impairment of the cellular component of the immune response was accompanied by increased apoptotic death of splenocytes, as is evident from the increased binding of the Annexin V-GFP tag to phosphatidyl serine residues exposed on the external side of the plasmalemma during apoptosis. Prolonged administration of vitamin D3 (during 2 months; dose 20 IU) promoted the normalization of proliferative activity and the relative size of T-cell subpopulations, led to a decrease of the content of the phosphorylated p65 subunit of NF-κB, and improved the balance of the secretion of IgG targeting the artificial antigen in diabetic animals. These changes were accompanied by a decrease in the number of apoptotic events in the entire splenocyte population. The results of the present study demonstrate the important role of vitamin D3 in the regulation of the functions of the immune system in type 1 diabetes.

Current Topics on Vitamin D. The role of active forms of vitamin D in regulation of bone remodeling

Active forms of vitamin D3 have been widely used in the treatment of rickets, osteomalacia, and osteoporosis in order to stimulate bone mineralization and prevent bone loss. Meanwhile, the active form of vitamin D3, 1α, 25-dihydroxyvitamin D3 [1α, 25 (OH) 2D3], upregulates expression of receptor activator of nuclear factor-κB ligand (RANKL) in osteoblastic cells. Osteoclast formation requires RANKL and macrophage colony-stimulating factor (M-CSF), which are expressed in osteoblastic cells. Recently, IL-34 was discovered as a cytokine functionally overlapping M-CSF. We found that administration of 1α, 25 (OH) 2D3 into mice enhanced IL-34 expression in spleen and bone. These results suggest that 1α, 25 (OH) 2D3 is a bone resorption-stimulating factor. However, daily administration of an active vitamin D3 analog (eldecalcitol, an osteoporotic therapeutic drug) for a month suppressed RANKL expression in osteoblasts, resulting in suppression of bone resorption. Here we discuss new findings and hypotheses to explain this contradictory effect of active vitamin D3 on bone remodeling.

Fall risk and fracture. Vitamin D and falls/fractures

Vitamin D affects both bone and muscle. Recent meta-analyses of high-quality trials showed that both native vitamin D and active forms of vitamin D3 significantly reduced the risk of vertebral and non-vertebral fractures. These anti-fracture efficacies of vitamin D are considered to be mainly exerted through direct effects on mineral metabolism. In addition, recent evidence suggests that vitamin D significantly prevents falls, to indirectly reduce fall-related fractures. The preventive effect on falls by vitamin D is considered to be exerted through effects on muscle, at least in part. Eldecalcitol, a new active vitamin D3 analogue, increases bone mineral density and shows greater evident anti-fracture efficacy than alfacalcidol. However, its effects in preventing falls remain unclear and warrant clarification.

Neuroprotective and immune effects of active forms of vitamin D3 and docosahexaenoic acid in Alzheimer disease patients

Neurodegenerative diseases, in particular Alzheimer disease (AD), afflict an increasing proportion of the older population with aging. Decreased exposure to sunlight and decreased consumption of fish, fruits, and vegetables, are two epidemiological factors that appear to be related to the pandemic of AD. In addition to replacing simple with complex carbohydrates and avoiding saturated fat, two nutritional components, vitamin D (acting through the endogenous hormonal form 1α,25 dihydroxyvitamin D, 1,25D) and docosahexaenoic acid (DHA) (acting through the docosanoid lipidic modulators resolvins and neuroprotectins) have high potential for prevention of Alzheimer disease. 1,25D is a neuroprotective, it acts both directly and indirectly in neurons by improving the clearance of amyloid-beta by macrophages/microglia. Resolvins and neuroprotectins inhibit amyloidogenic processing of amyloid-precursor protein, inflammatory cytokines, and apoptosis. It is likely that the increased consumption of vitamin D and fish oil could prevent neurodegeneration in some subjects by maintaining adequate endocrine, paracrine, and/or autocrine production of 1,25D and the DHA-derived lipidic modulators. Before firm recommendations of the dosage can be proposed, however, the in vivo effects of vitamin D3 and DHA supplementation should be investigated by prospective studies.Key words: Alzheimer disease, vitamin D3, DHA, fish oil

Topical Vitamin D3Is Effective in Treating Senile Warts Possibly by Inducing Apoptosis

Vitamin D3 ointments containing active forms of vitamin D3 are widely used to treat inflammatory keratotic dermatoses such as psoriasis. Senile wart or seborrheic keratosis is a benign tumor which occurs mainly in the elderly. It has traditionally been treated with surgical procedures, freezing with liquid nitrogen, or laser therapy. We treated senile warts with topical vitamin D3 ointments (tacalcitol, calcipotriol or maxacalcitol). Out of 116 cases treated for 3 to 12 months, 35 (30.2%) showed complete disappearance or more than an 80% decrease in the volume of the tumor, 54 cases (46.6%) showed a decrease in the volume between 40 and 80%, and no remarkable changes or decreases of less than 40% were seen in 27 cases (23.3%). The tumors faded without any inflammatory changes such as erythema or swelling. An organ culture experiment using senile wart as a material with several concentrations of tacalcitol revealed that tacalcitol induced apoptosis in the tissue. On the other hand, only sporadic apoptotic cells were seen in the controls (p<0.001). Vitamin D3 may affect senile warts by inducing apoptosis. Clearance of senile warts, especially on exposed areas without pain, may improve the quality of life (QOL) of the elderly.

Surgical treatment of patients with secondary hyperparathyroidism in chronic renal failure

The purpose of the study was to define indications for surgical treatment and its scope in patients with secondary hyperparathyroidism in the presence of end-stage chronic renalfailure. The authors examined 80 patients who had a history of long-term procedures of hemo- or peritoneal dialysis. The patients’ mean age was 47±3.2 years. Measurements of the levels of alkaline phosphatase, ionized and total calcium, phosphorus, parathyroid hormone, ultrasound of the parathyroid glands, densitometry and X-ray study were made in all the patients. All the patients received alfacalcidole therapy during different periods of time. Clinical, laboratory, and morphological correlations were made to establish indications for surgical treatment. The sensitivity ofpreoperative ultrasonography was 72.5% and that of intraoperative ultrasound study was as high as 98.4%. The sensitivity of intraoperative revision was 75%. Sixteen of the 20 patients operated on underwent total parathyroidectomy by autografting a fragment of one of the least glands into the muscle. Subtotal parathyroidectomy was made in 3 patients; 3 parathyroid glands were removed in 1. Emergency and planned studies were performed in all the patients. The duration of the patients operated on averaged 14 months. Three patients undergone total parathyroidectomy with autografiing developed signs of hyperparathyroidism following 6, 12, and 13 months, in this connection graft resection was made in these patients. In the follow-up periods of 3 to 6 months, the level of parathyroid hormone became normal after resurgery in 2 of these patients, hypoparathyroidism developed in one patient. Two months after surgery, recurrent secondary hyperthyroidism was detected in 2 of the 3 patients who had undergone subtotal parathyroidectomy (4 and 7 months after the occurrence of signs of transient hypoparathyroidism) and in 1 patient in whom 3 parathyroid glands had been removed. Four of the 20 patients operated on were observed to have hypoparathyroidism that was compensated by calcium preparations and active forms of vitamin D3. Thus, a good result was noted in 70% of the patients after surgical treatment.

An open study of vitamin D3 treatment in psoriasis vulgaris.

Active forms of vitamin D3, 1 alpha-hydroxyvitamin D3 and 1 alpha,25-dihydroxyvitamin D3, were administered in an open-design study to 40 patients with psoriasis vulgaris in three ways: to 17 patients 1 alpha-hydroxyvitamin D3 was given orally at a dose of 1.0 micrograms/day for 6 months, to four patients 1 alpha,25-dihydroxyvitamin D3 was given orally at a dose of 0.5 microgram/day for 6 months, and 19 patients were given 1 alpha,25-dihydroxyvitamin D3 applied topically at concentration of 0.5 microgram/g of base for 8 weeks. Improvement was observed at the end of the individual study periods in 13 (76%) patients in Group 1 with a mean period of treatment (+/- SD) of 2.7 +/- 0.6 months, in one patient in Group 2 at 3 months after the start of treatment, and in 16 (84%) patients in Group 3 when the chemical was applied for 3.3 +/- 1.2 weeks. No side-effects were observed in any of these trials. These data suggest that psoriasis may respond to active metabolites of vitamin D3 and that abnormalities in vitamin D metabolism or in responsiveness of the skin cells to active metabolites of vitamin D may be involved in the pathogenesis of this skin disease.