Active Metabolite Of Vitamin D3 Research Articles

Design, synthesis, and biological activity of D-bishomo-1α,25-dihydroxyvitamin D3 analogs and their crystal structures with the vitamin D nuclear receptor

The biologically active metabolite of vitamin D3 - calcitriol – is a hormone involved in the regulation of calcium-phosphate homeostasis, immunological processes and cell differentiation, being therefore essential for the proper functioning of the human body. This suggests many applications of this steroid in the treatment of diseases such as rickets, psoriasis and some cancers. Unfortunately, using therapeutic doses of calcitriol is associated with high concentrations of this compound which causes hypercalcemia. For this reason, new calcitriol analogs are constantly sought, devoid of calcemic effects but maintaining its beneficial properties. In this study, we present the synthesis of vitamin D derivatives characterized by an enlarged (seven-membered) ring D. Preparation of the designed vitamin D compounds required separate syntheses of crucial building blocks (C/D-rings fragments with side chain and rings A) which were combined by different methods, including Wittig-Horner reaction and Suzuki coupling. Biological activities of the target vitamin D analogs were assessed both in vitro and in vivo, demonstrating their significant potency compared to the natural hormone. Furthermore, the successful crystallization of these compounds with the vitamin D receptor (VDR) enabled us to investigate additional molecular interactions with this protein.

Strain specific differences in vitamin D3 response: impact on gut homeostasis.

Vitamin D3 regulates a variety of biological processes irrespective of its well-known importance for calcium metabolism. Epidemiological and animal studies indicate a role in immune regulation, intestinal barrier function and microbiome diversity. Here, we analyzed the impact of different vitamin D3- containing diets on C57BL/6 and BALB/c mice, with a particular focus on gut homeostasis and also investigated effects on immune cells in vitro. Weak regulatory effects were detected on murine T cells. By trend, the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 suppressed IFN, GM-CSF and IL-10 cytokine secretion in T cells of C57BL/6 but not BALB/c mice, respectively. Using different vitamin D3-fortified diets, we found a tissue-specific enrichment of mainly CD11b+ myeloid cells but not T cells in both mouse strains e.g. in spleen and Peyer's Patches. Mucin Reg3γ and Batf expression, as well as important proteins for gut homeostasis, were significantly suppressed in the small intestine of C57BL76 but not BALB/c mice fed with a high-vitamin D3 containing diet. Differences between both mouse stains were not completely explained by differences in vitamin D3 receptor expression which was strongly expressed in epithelial cells of both strains. Finally, we analyzed gut microbiome and again an impact of vitamin D3 was detected in C57BL76 but not BALB/c. Our data suggest strain-specific differences in vitamin D3 responsiveness under steady state conditions which may have important implications when choosing a murine disease model to study vitamin D3 effects.

Age-Dependent Effect of Calcitriol on Mouse Regulatory T and B Lymphocytes.

The hormonally active vitamin D3 metabolite, calcitriol, functions as an important modulator of the immune system. We assumed that calcitriol exerts different effects on immune cells and cytokine production, depending on the age of the animal; therefore, we analyzed its effects on regulatory T lymphocytes and regulatory B lymphocytes in healthy young and old female C57Bl/6/Foxp3GFP mice. In the lymph nodes of young mice, calcitriol decreased the percentage of Tregs, including tTregs and pTregs, and the expression of GITR, CD103, and CD101; however, calcitriol increased the level of IL-35 in adipose tissue. In the case of aged mice, calcitriol decreased the percentages of tTregs and CD19+ cells in lymph nodes and the level of osteopontin in the plasma. Additionally, increases in the levels of IgG and the lowest levels of IFN-γ, IL-10, and IL-35 were observed in the adipose tissue of aged mice. This study showed that calcitriol treatment had different effects, mainly on Treg phenotypes and cytokine secretion, in young and old female mice; it seemed that calcitriol enhanced the immunosuppressive properties of the lymphatic organs and adipose tissue of healthy young mice but not of healthy aged mice, where the opposite effects were observed.

Metabolism of vitamin D, Calcium and Phosphorus and their disorders in goats

The review article presents materials on the metabolism of the mostcommon vitamins of group D ergocalciferol (D2), cholecalciferol (D3), aswell as essential macronutrients Ca and Phosphorus and their disorders ingoats. Since the primary forms of vitamin D (D2 and D3) are biologicallyinactive and must undergo several stages of hydroxylation to be activated,the biological role and importance for the body of active metabolites ofvitamin D3 25OH D3 (synthesised mainly in the liver under the influenceof hepatic cytochromes P450) and 1, 25(OH)2 D3 and 24,25(OH)2 D3 (theirsynthesis occurs via 1α-hydroxylase in the mitochondria of proximal cellsof the convoluted tubules of the kidneys).It is believed that the liver, while playing an important role in themetabolism of vitamin D and its metabolites and producing 25OH D3, isalso the only organ that synthesises DBP, which transports 25OH D3 totissues and maintains its concentration in the circulatory system.Vitamin D becomes biologically active only after the second stageof hydroxylation is completed. Renal 1α-hydroxylase (CYP27B1),regulated by parathyroid hormone (PTH), plays an important role inthe transformation of the extracellular substrate 25OH D3 to 1,25(OH)2D3, which exerts its effect on target cells and tissues by binding to thenuclear vitamin D receptor. Alternatively, 1,25(OH)2 D3 can bind to theplasma membrane VDR and induce non-genomic actions, in particular,stimulation of intestinal calcium transport.Vitamin D is a steroid substance that is essential for all vertebratesto maintain calcium and phosphorus metabolism within optimal limits, ahealthy skeleton, muscle contraction, modulation of cell growth and neuromuscular function. Calciferol also regulates the immune system, inhibits the development of pathological cells, angiogenesis and inflammatoryreactions. The active form of vitamin D, 1,25(OH)2 D3, stimulates intestinal absorption and renal Ca reabsorption and maintains its minimumphysiological level in the blood.Vitamin D deficiency in goats leads to a decrease in productivity, causesa decrease in intestinal and renal calcium reabsorption, which leads to theincrease in parathyroid hormone levels. This process leads to activation ofosteocytes and, as a result, accelerates bone demineralisation, causing thedevelopment of many diseases in adults, including nutritional and fibrousosteodystrophy, secondary osteodystrophy, endocrine dysfunction), as wellas rickets in young animals. The development of non-skeletal pathologies,in particular, inflammatory, neoplastic and autoimmune diseases, is also associated with cholecalciferol deficiency in the body. In addition, disordersof D-vitamin and calcium-phosphorus metabolism in goats cause the development of postpartum hypocalcaemia and postpartum hypophosphatemia.In the animal body, calcium and phosphorus homeostasis is maintained by a coordinated interaction of absorption and reabsorptionthrough the gastrointestinal tract and kidneys, as well as by storage and mobilization from bone tissue and is regulated mainly by biologically active cholecalciferol metabolites - 25OH D3, 1,25(OH)2 D3, as wellas parathyroid hormone (PTH; synthesised by the pineal glands) andcalcitonin (CT; produced by sparafollicular (light) thyroid C cells) andfibroblast growth factor-23 (FGF23).In contrast to monogastric animals, small ruminants do not modulaterenal calcium excretion in response to calcium limitation in the diet. Themobilization of Ca and P from the skeleton is stimulated by PTH throughosteoclast activation mediated by receptor activator of nuclear factor-κB(RANK). Vitamin D maintains Ca (by stimulating CaZB) and P homeostasis (the direct rapid action of 1,25(OH)2 D3 has been proven to have a directeffect on the absorption of these vital elements in the intestine, reabsorptionof these cations in the renal tubules and their mobilization from bone tissue).Phosphorus is a component of adenosine triphosphate (ATP) and nucleotides. Macroergic phosphate compounds, among which the main oneis adenosine triphosphate acid, provide both the accumulation of energyreserves and its consumption (ATP, ADP, creatine phosphate), affectingprotein, lipid, carbohydrate, mineral, and energy metabolism. An interaction between vitamin D and fibroblast growth factor 23 (FGF23), a bonehormone that causes the development of phosphaturia and reduces thesynthesis of 1,25(OH)2 D3, has been identified.Despite the multidirectionality of etiological factors, common to allforms of osteodystrophy is a disruption of the processes of bone formation and renewal, which is manifested by increased mobilization of calcium, phosphorus and other elements from bone tissue, so the pathologyis accompanied by osteomalacia, osteoporosis and osteofibrosis, and aviolation of the mechanism of maintaining their homeostasis.The main factors of osteodystrophy in animals are feeding disordersand physical inactivity, and the leading links in its pathogenesis are theimbalance between bone formation and resorption.The main methods for diagnosing disorders of D-vitamin and calcium-phosphorus metabolism in goats are clinical, physical, biochemical,enzyme-linked immunosorbent assays and pathological and morphological studies. Biochemical analysis in goat serum determines the content oftotal calcium, inorganic phosphorus, activity of alkaline phosphatase andits isozymes, and immunoassay the concentration of 25OH D3, 1,25(OH)2D3, calcitonin and parathyroid hormone. Keywords: goats, vitamin D, metabolites, metabolism, calcium,phosphorus, liver, kidneys.

Vitamin D3 supplementation improves spatial memory, muscle function, pain score, and modulates different functional physiological biomarkers in vitamin D3 deficiency diet (VDD)-induced rats model

BackgroundVitamin D Deficiency is recognized as a pandemic, which is associated with high mortality. An inadequate level of vitamin D is associated with autoimmune diseases, hypertension, and cancer. The study was aimed to assess the pharmacological effects of chronic vitamin D3 supplementation on the manipulation diet regiment of deprived cholecalciferol (vitamin D3 deficient diet, VDD) rats.MethodsMemory performance (Y-maze task), muscular function (muscle grip strength), and pain score (pressure application measurement meter) were measured. Functional biomarkers were measured using ELISA method in different matrix viz. in serum (parathyroid hormone; PTH, calcitonin, thyroxine, and C-reactive protein; CRP, 25-OH Vit D3), and in CSF (klotho and β-endorphin). 25-OH Vit D3 was also estimated in liver and kidney homogenate using ELISA. Vitamin D receptor (VDR) was measured spectrophotometrically in liver and adipose tissue.ResultsVDD-induced rats showed a decrease in number of entries and time spent in the novel arm and spontaneous alternations in the Y-maze task. Significant improvements of neuromuscular function and pain score after addition of vitamin D3. In comparison to the VDD group, VDR expression (liver) and active metabolites of vitamin D3 (25-OH vit.D3) in serum were significantly higher by 48.23% and 280%, respectively. The PTH and CRP levels were significantly reduced by 32.5% and 35.27%, respectively, whereas calcitonin was increased by 36.67% compared with the VDD group. Klotho and β-endorphin expressions in cerebrospinal fluid were significantly elevated by 19.67% and 133.59%, respectively, compared to VDD group.ConclusionsOverall, the results indicate that supplementation of cholecalciferol significantly improved spatial memory impairment, VDR expression, and may provide an opportunity to manage vitamin D deficiencies.

Local production of active vitamin D3 metabolites in breast cancer cells by CYP24A1 and CYP27B1

The role of vitamin D3 and its metabolites in cancer and especially as a treatment option has been widely disputed. Clinicians noting low serum 25-hydroxyvitamin D3 [25(OH)D3] levels in their patients, recommend vitamin D3 supplementation as a method of reducing the risk of cancer; however, data supporting this are inconsistent. These studies rely on systemic 25(OH)D3 as an indicator of hormone status, but 25(OH)D3 is further metabolized in the kidney and other tissues under regulation by several factors. This study examined if breast cancer cells also possess the ability to metabolize 25(OH)D3, and if so, whether the resulting metabolites are secreted locally; if this ability reflects ERα66 status; and if they possess vitamin D receptors (VDR). To address this question, estrogen receptor alpha (ERα) positive (MCF-7) and ERα negative (HCC38 and MDA-MB-231) breast cancer cell lines were examined for expression of ERα66, ERα36, CYP24A1, CYP27B1, and VDR as well as for local production of 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] after treatment with 25(OH)D3. The results showed that independent of ER status, breast cancer cells express the enzymes CYP24A1 and CYP27B1, which are responsible for converting 25(OH)D3 into its dihydroxylated forms. Moreover, these metabolites are produced at levels comparable to the levels observed in blood. They are positive for VDR, indicating that they can respond to 1α,25(OH)2D3, which can upregulate CYP24A1. These findings suggest that vitamin D metabolites may contribute to the tumorigenicity of breast cancer via autocrine and/or paracrine mechanisms.

Vitamin D (1α,25(OH)2D3) supplementation minimized multinucleated giant cells formation and inflammatory response during Burkholderia pseudomallei infection in human lung epithelial cells.

Melioidosis is an infectious disease with high mortality rates in human, caused by the bacterium Burkholderia pseudomallei. As an intracellular pathogen, B. pseudomallei can escape from the phagosome and induce multinucleated giant cells (MNGCs) formation resulting in antibiotic resistance and immune evasion. A novel strategy to modulate host response against B. pseudomallei pathogenesis is required. In this study, an active metabolite of vitamin D3 (1α,25-dihydroxyvitamin D3 or 1α,25(OH)2D3) was selected to interrupt pathogenesis of B. pseudomallei in a human lung epithelium cell line, A549. The results demonstrated that pretreatment with 10-6 M 1α,25(OH)2D3 could reduce B. pseudomallei internalization to A549 cells at 4 h post infection (P < 0.05). Interestingly, the presence of 1α,25(OH)2D3 gradually reduced MNGC formation at 8, 10 and 12 h compared to that of the untreated cells (P < 0.05). Furthermore, pretreatment with 10-6 M 1α,25(OH)2D3 considerably increased hCAP-18/LL-37 mRNA expression (P < 0.001). Additionally, pro-inflammatory cytokines, including MIF, PAI-1, IL-18, CXCL1, CXCL12 and IL-8, were statistically decreased (P < 0.05) in 10-6 M 1α,25(OH)2D3-pretreated A549 cells by 12 h post-infection. Taken together, this study indicates that pretreatment with 10-6 M 1α,25(OH)2D3 has the potential to reduce the internalization of B. pseudomallei into host cells, decrease MNGC formation and modulate host response during B. pseudomallei infection by minimizing the excessive inflammatory response. Therefore, 1α,25(OH)2D3 supplement may provide an effective supportive treatment for melioidosis patients to combat B. pseudomallei infection and reduce inflammation in these patients.

Dietary 25-hydroxycholecalciferol modulates gut microbiota and improves the growth, meat quality, and antioxidant status of growing-finishing pigs.

25-Hydroxycholecalciferol (25OHD3) is the active metabolite of regular vitamin D3 in vivo, which has a stronger biological activity and is more easily absorbed by the intestine than regular vitamin D3. Our study aimed to detect the potential influences of 25OHD3 on pork quality, antioxidant status, and intestinal microbiota of growing-finishing pigs receiving low-phosphorus (P) diet. Forty pigs [initial body weight (BW): 49.42 ± 4.01 kg] were allocated into two groups including low-P diet (CON group) and low-P diet supplemented with 50 μg/kg 25OHD3 (25OHD3 group). The whole experiment lasted for 88 days, including phase 1 (day 1-28), phase 2 (day 29-60), and phase 3 (day 61-88). The results showed that 25OHD3 supplementation tended to decrease feed conversion ratio in phase 3 and overall phase in comparison with the CON group. 25OHD3 increased (p < 0.05) serum contents of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and decreased (p < 0.05) serum bone-specific alkaline phosphatase level. 25OHD3 increased (p < 0.05) mucosal GSH-Px activity in the duodenum and ileum, and tended to increase redness value and the activities of total antioxidant capacity and SOD in longissimus dorsi. 25OHD3 significantly upregulated the mRNA level of copper/zinc superoxide dismutase, and tended to change the mRNA levels of nuclear factor E2-related factor 2 and kelch-like ECH-associated protein 1 in longissimus dorsi. Moreover, 25OHD3 supplementation decreased (p < 0.05) n-6/n-3 and iodine value in longissimus dorsi. For bone quality, 25OHD3 supplementation increased (p < 0.05) calcium content, bone mineral content, and breaking strength in the metacarpal bones. Moreover, the colonic abundance of Lactobacillus was significantly higher in pigs fed with 25OHD3, and exhibited a positive association with serum antioxidant status, pork quality, and bone characteristics. Overall, the inclusion of 25OHD3 in low P diet partly improved production performance, meat quality, antioxidant capacity, bone properties, and gut microbiota composition of growing-finishing pigs.

Preparation and Evaluation of Low-Dose Calcitriol Dry Powder Inhalation as Host-Directed Adjunct Therapy for Tuberculosis.

BackgroundIt is unclear whether Vitamin D is efficacious as a host-directed therapy (HDT) for patients of tuberculosis (TB). We investigated pulmonary delivery of the active metabolite of Vitamin D3, i.e., 1, 25-dihydroxy vitamin D3 (calcitriol) in a mouse model of infection with Mycobacterium tuberculosis (Mtb).MethodsWe optimized a spray drying process to prepare a dry powder inhalation (DPI) of calcitriol using a Quality by Design (QbD) approach. We then compared outcomes when Mtb-infected mice were treated with inhaled calcitriol at 5 ng/kg as a stand-alone intervention versus DPI as adjunct to standard oral anti-tuberculosis therapy (ATT).ResultsThe DPI with or without concomitant ATT markedly improved the morphology of the lungs and mitigated histopathology in both the lungs and the spleens. The number of nodular lesions on the lung surface decreased from 43.7 ± 3.1 to 22.5 ± 3.9 with the DPI alone and to 9.8 ± 2.5 with DPI + ATT. However, no statistically significant induction of host antimicrobial peptide cathelicidin or reduction in bacterial burden was seen with the DPI alone. DPI + ATT did not significantly reduce the bacterial burden in the lungs compared to ATT alone.ConclusionsWe concluded that HDT using the low dose calcitriol DPI contributed markedly to mitigation of pathology, but higher dose may be required to evoke significant induction of bactericidal host response and bactericidal activity in the lung. Supplementary InformationThe online version contains supplementary material available at 10.1007/s11095-022-03360-5.

Abstract 2693: The vitamin D3 metabolite, 24R,25(OH)3D3 is differentially tumorigenic in ER+ and ER- laryngeal cancer cells in vitro

Abstract Due to the high vitamin D3 levels associated with improved prognosis (but not incidence) in post-menopausal breast cancer patients with ER+ tumors, vitamin D3 supplementation has been used as potential therapeutics. 24R,25(OH)2D3, an active metabolite of vitamin D3, is known to protect cartilage cells through a membrane-initiated, p53-mediated pathway, suggesting that 24R,25(OH)2D3 may affect cancer cells through a similar mechanism. Our lab has shown that the effect of 24R,25(OH)2D3 on breast cancer cell growth is highly dependent on the expression levels of ERα isoforms, specifically ERα66. Understanding the mechanisms by which 24R,25(OH)2D3 affects tumor growth in breast cancer will aid in determining its therapeutic potential in another estrogen responsive cancer, laryngeal cancer. The goal of this study was to examine the effects of 24R,25(OH)2D3 on proliferation, apoptosis, and epithelial to mesenchymal transition (EMT) in laryngeal cancer cell lines. To assess the effect of 24R,25(OH)2D3 on cell growth, UM-SCC-12 (ERα66+) and UM-SCC-11A (ERα66-) cell lines were cultured on 96 well plates until 80% confluence. Cells were serum starved for 24 hours pretreatment and then treated with full media containing either vehicle, or 24R,25(OH)2D3 (10-9M, 10-8M, or 10-7M) for 15 minutes, at which time the media were replaced with fresh media. After 20 hours, cells were harvested for proliferation by EDU assay. For other experiments cells were treated with either vehicle, or 24R,25(OH)2D3 (10-9M, 10-8M, or 10-7M) for 15 minutes and after 24 hours, cells were assessed for apoptosis (TUNEL, P53) and metastasis (OPG/RANKL). 12 hours after treatment, cells were harvested for PCR and examined for gene expression of apoptotic markers (BAX, BCL2) and various metastatic markers (SNAI1, ERBB2). 24R,25(OH)2D3 decreased proliferation in ERα66- cells (UM-SCC-11A) with the 10-7M dosage. It also increased apoptotic markers (TUNEL, P53, BAX/BCL2 expression). EMT and metastatic markers (ERBB2, SNAI1 expression) as well as bone metastatic markers (OPG/RANKL) were reduced. Conversely, in ERα66+ cells (UM-SCC-12) 24R,25(OH)2D3 had the opposite effect, increasing proliferation with 10-7M 24R,25(OH)2D3 treatment as well as decreasing DNA fragmentation (TUNEL). Treatment with 24R,25(OH)2D3 increased total P53 content and had no effect on EMT, BAX/BCL2 or other metastatic markers (SNAI1, ERBB2, OPG, RANKL). These data show that 24R,25(OH)2D3 is functionally active in laryngeal cancer tumor regulation. Contrary to results shown in breast cancer in which 24R,25(OH)2D3 was pro-tumorigenic in ERα66- cells, 24R,25(OH)2D3 was anti-tumorigenic in ERα66- laryngeal cancer cells. While this difference may be a result of a difference in other aspects of the two ERα66- cell lines, these results provide evidence of the therapeutic potential of 24R,25(OH)2D3 in laryngeal cancer and its ERα66 dependent effect. Citation Format: Cydney D. Dennis, David Joshua Cohen, Barbara D. Boyan, Zvi Schwartz. The vitamin D3 metabolite, 24R,25(OH)3D3 is differentially tumorigenic in ER+ and ER- laryngeal cancer cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2693.

Vitamin D May Protect against Breast Cancer through the Regulation of Long Noncoding RNAs by VDR Signaling.

Dietary vitamin D3 has attracted wide interest as a natural compound for breast cancer prevention and therapy, supported by in vitro and animal studies. The exact mechanism of such action of vitamin D3 is unknown and may include several independent or partly dependent pathways. The active metabolite of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D, calcitriol), binds to the vitamin D receptor (VDR) and induces its translocation to the nucleus, where it transactivates a myriad of genes. Vitamin D3 is involved in the maintenance of a normal epigenetic profile whose disturbance may contribute to breast cancer. In general, the protective effect of vitamin D3 against breast cancer is underlined by inhibition of proliferation and migration, stimulation of differentiation and apoptosis, and inhibition of epithelial/mesenchymal transition in breast cells. Vitamin D3 may also inhibit the transformation of normal mammary progenitors into breast cancer stem cells that initiate and sustain the growth of breast tumors. As long noncoding RNAs (lncRNAs) play an important role in breast cancer pathogenesis, and the specific mechanisms underlying this role are poorly understood, we provided several arguments that vitamin D3/VDR may induce protective effects in breast cancer through modulation of lncRNAs that are important for breast cancer pathogenesis. The main lncRNAs candidates to mediate the protective effect of vitamin D3 in breast cancer are lncBCAS1-4_1, AFAP1 antisense RNA 1 (AFAP1-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), long intergenic non-protein-coding RNA 511 (LINC00511), LINC00346, small nucleolar RNA host gene 6 (SNHG6), and SNHG16, but there is a rationale to explore several other lncRNAs.

Physiological levels of 25-hydroxyvitamin D3 induce a suppressive CD4+ T cell phenotype not reflected in the epigenetic landscape.

1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), the active metabolite of vitamin D3 has a strong impact on the differentiation and function of immune cells. Here we analysed the influence of its precursor 25-hydroxyvitamin D3 (25(OH)D3 ) on the differentiation of human CD4+ T cells applying physiological concentrations in vitro. Our data show that 25(OH)D3 is converted to its active form 1,25(OH)2 D3 by T cells, which in turn supports FOXP3, CD25 and CTLA-4 expression and inhibits IFN-γ production. These changes were not reflected in the demethylation of the respective promoters. Furthermore, we investigated the impact of vitamin D3 metabolites under induced Treg (iTreg) polarization conditions using TGF-β. Surprisingly, no additive effect but a decreased percentage of FOXP3 expressing cells was observed. However, the combination of 25(OH)D3 or 1,25(OH)2 D3 together with TGF-β further upregulated CD25 and CTLA-4 and significantly increased soluble CTLA-4 and IL-10 secretion whereas IFN-γ expression of iTreg was decreased. Our data suggest that physiological levels of 25(OH)D3 act as potent modulator of human CD4+ T cells and autocrine or paracrine production of 1,25(OH)2 D3 by T cells might be crucial for the local regulation of an adaptive immune response. However, since no epigenetic changes are detected by 25(OH)D3 a rather transient phenotype is induced.

Potential of a rumen bolus containing 1,25-dihydroxyvitamin D3 glycosides for the prevention of hypocalcaemia in primiparous and multiparous dairy cows

Periparturient hypocalcaemia is a widespread metabolic disorder in dairy cows. Clinical and subclinical cases occur primarily in multiparous (Multi) cows, but subclinical cases have also been reported in primiparous (Primi) cows. A preventive strategy was investigated by administering the physiologically active vitamin D3 metabolite, 1,25-dihydroxyvitamin D3 (1,25-dihydroxycholecalciferol, 1,25(OH)2D3) as a rumen bolus. The bolus contained tablets of 1,25(OH)2D3 glycoside extract from Solanum glaucophyllum (SGE), releasing SGE over several days. The aim was to study the effect of a bolus containing 0 (C) or 500 µg (SGE) of 1,25(OH)2D3 on 1,25(OH)2D3 and mineral status in periparturient cows up to three weeks into lactation and on colostrum, milk and calves’ blood mineral contents. The bolus was administered three to four days prior to expected calving to Primi and Multi cows fed a herbage-based diet (dietary cation-anion difference of +522 mEq/kg DM). One C or SGE bolus was applied to 12 Primi and 12 Multi cows. Blood was regularly sampled (and selected a posteriori for antepartum samples) in regard to the actual calving day (d0), immediately prior to bolus application and at day −2, 0.5, 1, 1.5, 2, 4, 8, 11, 15, 18 and 22. Additional samples included urine (at bolus application, d0.5 and d2), colostrum, milk samples (weekly) and calves’ blood (d2). Blood serum 1,25(OH)2D3 increased between d0.5 and d2 in Primi-SGE, but remained unchanged in Primi-C, as did parathyroid hormone (PTH) and Ca in all Primi. Urinary Ca of Primi-SGE was increased on d2, indicating regulation of Ca excess. Three Multi-C cows with confirmed clinical hypocalcaemia needed treatment and thus were excluded from the dataset and replaced. Blood serum 1,25(OH)2D3 and PTH increased while Ca dropped by 40% between d0.5 and d2 in Multi-C, whereas 1,25(OH)2D3, Ca and PTH remained unchanged in Multi-SGE. Blood serum carboxyterminal telopeptide of type I collagen was higher in Primi than in Multi and increased with time, except in Primi-C. Mineral contents in colostrum, milk and blood serum of calves were not influenced to a relevant degree. In conclusion, Primi-C did not, in contrast to Multi-C, develop subclinical hypocalcaemia (<2.0 mmol Ca/l). Prevention of hypocalcaemia with one SGE bolus applied three to four days prior to expected calving was successful in maintaining blood Ca within normal range in Multi over the critical first two days and up to the first three weeks of lactation, without any observed detrimental effects on cows or calves.

Pharmacokinetics of 1,25-dihydroxyvitamin D3 glycosides from Solanum glaucophyllum extract given in a rumen bolus on blood mineral profiles in dry pregnant dairy cows

Providing tablets of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the biologically active metabolite of vitamin D3, in a rumen bolus may be used as prevention for periparturient hypocalcemia in dairy cows. This study investigated the pharmacokinetics of 1,25(OH)2D3 glycosides extracted from Solanum glaucophyllum (SGE) on blood serum 1,25(OH)2D3, Ca, P and Mg response in dry pregnant dairy cows. Boluses contained tablets of SGE which differed in their release properties (rapid release, slow release and combination) and galenics (200 μg uncoated, 300 μg and 500 μg uncoated or coated, 2 × 500 μg uncoated). Nineteen blood samples were collected from 29 cows between 96 h before and 336 h after bolus administration. Blood serum 1,25(OH)2D3, Ca and P increased between 12 h and 120 h, 12 h and 264 h and 24 h and 264 h, respectively. Highest values were reached at 30 h, 72 h and 120 h for 1,25(OH)2D3, Ca and P, respectively. Baseline values were then reached at 216 h for 1,25(OH)2D3 and 336 h for Ca and P. Concentration of Mg decreased between 24 h and 216 h, before reaching values comparable to baseline at 264 h. Highest Ca values were obtained with the combined rapid and slow release properties (500 μg) and there was no effect from coating on pharmacokinetics. In conclusion, the antepartum oral SGE bolus administration may be suitable for the prevention of periparturient hypocalcemia.

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.

Role of Hormones in Oral Squamous Cell Carcinoma - An Update

Background: Hormones have been recognized as regulator of the cell growth, differentiation and maturation. It has become increasingly evident that hormone may play a crucial role in the genesis and progression of several cancers like those of breast, ovary, testis, thyroid, prostrate including oral cancer.&#x0D; Aim: Present overview aims to discuss and provide data on possible role of various hormones including stress hormone, sex hormone, parathyroid and related hormone protein, melatonin and active metabolite of vitamin D3 in causation and progression of Oral squamous cell carcinoma (OSCC).&#x0D; Data Acquisition: A systematic search of existing literature was carried out for the keywords like hormones and cancer, hormones and oral cancer or OSCC utilizing the Google, Google Scholar and PubMed databases for extraction, assortment and compilation of data.&#x0D; Inference: In conclusion, we found that hormones are directly or indirectly involved in the pathogenesis of the OSCC and can be utilized in its management and prevention.

Vitamin D Compounds PRI-2191 and PRI-2205 Enhance Anastrozole Activity in Human Breast Cancer Models.

1,25-Dihydroxycholecalciferol, the hormonally active vitamin D3 metabolite, is known to exhibit therapeutic effects against breast cancer, mainly by lowering the expression of estrogen receptors and aromatase activity. Previously, the safety of the vitamin D active metabolite (24R)-1,24-dihydroxycholecalciferol (PRI-2191) and 1,25(OH)2D3 analog PRI-2205 was tested, and the in vitro activity of these analogs against different cancer cell lines was studied. We determined the effect of the two vitamin D compounds on anastrozole (An) activity against breast cancer based on antiproliferative activity, ELISA, flow cytometry, enzyme inhibition potency, PCR, and xenograft study. Both the vitamin D active metabolite and synthetic analog regulated the growth of not only estrogen receptor-positive cells (T47D and MCF-7, in vitro and in vivo), but also hormone-independent cancer cells such as SKBR-3 (HER-2-positive) and MDA-MB-231 (triple-negative), despite their relatively low VDR expression. Combined with An, PRI-2191 and PRI-2205 significantly inhibited the tumor growth of MCF-7 cells. Potentiation of the antitumor activity in combined treatment of MCF-7 tumor-bearing mice is related to the reduced activity of aromatase by both An (enzyme inhibition) and vitamin D compounds (switched off/decreased aromatase gene expression, decreased expression of other genes related to estrogen signaling) and by regulation of the expression of the estrogen receptor ERα and VDR.

1α,25-Dihydroxyvitamin D3 synergistically enhances anticancer effects of ginsenoside Rh2 in human prostate cancer cells

1α,25-dihydroxyvitamin D3 (1,25(OH)2D3, commonly known as calcitriol), the most active metabolite of vitamin D3, and ginsenoside Rh2 can regulate cellular differentiation and proliferation proteins. The purpose of the present study was to assess the effect of 1,25(OH)2D3 on the anticancer activities of Rh2 in human prostate cancer cells such as androgen-dependent LNCaP and androgen-independent C4-2 in vitro. The effects of treatment with 1,25(OH)2D3 or Rh2, either alone or in combination, on prostate cancer cells were evaluated through tetrazolium-based cell viability assay, BrdU cell proliferation rate estimation assay, and Western blot protein expression analyses of nuclear receptors (androgen receptor and vitamin D receptors) and apoptotic proteins (Bcl-2, Bax, and Caspase 3). The Combination Indices (CI) and Dose Reduction Indices (DRI) of 1,25(OH)2D3 and Rh2 were calculated to determine synergistic anticancer activity using Calcusyn software (Biosoft, Cambridge, UK). The cell viability assay data indicate that Rh2 treatment alone inhibited cell viability in a concentration-dependent manner and the addition of 10 nM 1,25(OH)2D3 to Rh2 significantly enhanced its ability to reduce cell viability up to 80 % in both the cell lines. Similarly, addition of 10 nM 1,25(OH)2D3 to Rh2 significantly lowered its IC50 values for cell proliferation from the range of 32–65 μM to 14-8 μM in LNCaP and C4-2 cells. In addition, protein expression analyses indicated that the combined treatment with Rh2 and 1,25(OH)2D3 led to greater downregulation of androgen receptor expression compared to single agent exposure. Similarly, the presence of 1,25(OH)2D3 synergistically increased the pro-apoptotic actions of Rh2 in both the cell lines. Overall, 1,25(OH)2D3 augments the Rh2-mediated anticancer effects through stimulating apoptosis and reduced cell proliferation which suggests that synergism of this combination may lead to potential lower need of the active vitamin D3 and limited toxicity from it.

The Relative Expression of ERα Isoforms ERα66 and ERα36 Controls the Cellular Response to 24R,25-Dihydroxyvitamin D3 in Breast Cancer.

Vitamin D3 and its metabolites have antitumorigenic properties in vitro and in vivo; however, clinical trials and retrospective studies on the effectiveness of vitamin D3 oral supplementation against cancer have been inconclusive. One reason for this may be that clinical trials ignore the complex vitamin D metabolome and the many active vitamin D3 metabolites present in the body. Recent work by our lab showed that 24R,25(OH)2D3, a vitamin D3 metabolite that is active in chondrocyte proliferation and differentiation, has antitumorigenic properties in estrogen receptor alpha-66 (ERα66)-positive (ER+) breast cancer, but not in ERα66-negative (ER-) breast cancer. Here we show that 24R,25(OH)2D3 is protumorigenic in an in vivo mouse model (NOD.Cg-PrkdcscidIl2rgtm1Wjl /SzJ (NSG) mice) of ER- breast cancer, causing greater tumor growth than in mice treated with vehicle alone. In vitro results indicate that the effect of 24R,25(OH)2D3 is via a membrane-associated mechanism involving ERs and phospholipase D. 24R,25(OH)2D3 increased proliferation and reduced apoptosis in ERα66-negative HCC38 breast cancer cells, and stimulated expression of metastatic markers. Overexpressing ESRI, which encodes ERα66, ERα46, and ERα36, reduced the proapoptotic response of ERα66- cells to 24R,25(OH)2D3, possibly by upregulating ERα66. Silencing ESR1 in ERα66+ cells increased apoptosis. This suggests 24R,25(OH)2D3 is differentially tumorigenic in cancers with different ERα isoform profiles. Antiapoptotic actions of 24R,25(OH)2D3 require ERα36 and proapoptotic actions require ERα66. IMPLICATIONS: These results suggest that 24R,25(OH)2D3, which is a major circulating metabolite of vitamin D, is functionally active in breast cancer and that the regulatory properties of 24R,25(OH)2D3 are dependent upon the relative expression of ERα66 and ERα36.

Vitamin D Metabolite Profile in Cholecalciferol- or Calcitriol-Supplemented Healthy and Mammary Gland Tumor-Bearing Mice.

To analyze if the prometastatic activity of calcitriol (active vitamin D3 metabolite), which was previously observed in a 4T1 breast cancer model, is also found in other breast cancers, and to assess the impact of various schemes of vitamin D supply, we used 4T1 and E0771 mouse metastatic and 67NR nonmetastatic cells in this study. BALB/c and C57BL/6 healthy and tumor-bearing mice were exposed to a control (1000 IU), low- (100 IU), and high- (5000 IU) vitamin D3 diets. Additionally, from day 7 of tumor transplantation, the 1000 and 100 IU groups were gavaged with calcitriol (+cal). After 8 weeks of feeding, plasma levels of 25(OH)D3, 24,25(OH)2D3, and 3-epi-25(OH)D3 were significantly lower in calcitriol-treated and vitamin D-deficient groups than in the control, whereas the levels of all metabolites were increased in the 5000 IU group. The ratio of 25(OH)D3:24,25(OH)2D3 was increased in both calcitriol-treated groups, whereas the ratio of 25(OH)D3:3-epi-25(OH)D3 was increased only in the 100 IU group but decreased in the 5000 IU group. In contrast to E0771, 4T1 lung metastasis was accelerated in all vitamin D-supplemented mice, as well as in the deficient group with an increased inflammatory response. 67NR tumor growth was transiently inhibited in the 1000 IU+cal group, but single metastases were observed in the 5000 and 100 IU groups. Based on the results, we conclude that various schemes of vitamin D supply and vitamin D deficiency led to similar metabolite profiles irrespective of the mice strain and tumor burden. However, depending on the type of breast cancer, different effects on tumor growth and metastasis were noticed.