Vitamin D and cancer

Vitamin D3 and cancer risk in healthy subjects: An umbrella review of systematic review and meta-analysis

INTRODUCTION

Vitamin D3, which originates from cholesterol, exerts its influence on immune cells and potentially cancer cells via the metabolite 1,25-dihydroxycholecalciferol (1,25(OH)2D3), impacting their proliferation, differentiation, and apoptosis. An umbrella review was conducted to evaluate the potential protective effect of vitamin D3 intake and serum levels on the incidence and mortality of cancer.

MATERIAL AND METHODS

A systematic search was conducted in MEDLINE, Cochrane Central Register of Controlled Trials, and EMBASE databases from their inception to October 1, 2023. We included meta-analyses of observational or randomized clinical trials that compared interventions (vitamin D3 intake) or blood levels in a healthy population, with cancer incidence or mortality as outcomes. The grading of evidence certainty followed established criteria, including strong, highly suggestive, suggestive, weak, or not significant.

RESULTS

A total of 71 systematic reviews were included. Strong evidence indicated that vitamin D3 supplementation reduced total cancer mortality (odds ratio [OR], 0.9 [95% CI, 0.87-0.92]; P < 0.01). In the context of site-specific cancers, there exists highly suggestive evidence pointing towards the potential prevention of head and neck, breast, colorectal, lung, and renal cell cancers through the intake of vitamin D3. Furthermore, strong evidence suggests that maintaining sufficient levels of vitamin D3 may effectively lower the risk of renal cell and thyroid cancer (OR = 0.76 [95%CI 0.64-0.88]).

CONCLUSIONS

There is significant evidence that vitamin D3 intake may reduce the incidence of some cancers. Routine assessments to ensure sufficient levels of vitamin D3 and administering supplements to address deficiencies may serve as crucial preventive measures for healthcare systems.

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.

Full-length nuclear receptor allosteric regulation

Nuclear receptors are a superfamily of transcription factors regulated by a wide range of lipids that include phospholipids, fatty acids, heme-based metabolites, and cholesterol-based steroids. Encoded as classic two-domain modular transcription factors, nuclear receptors possess a DNA-binding domain (DBD) and a lipid ligand-binding domain (LBD) containing a transcriptional activation function. Decades of structural studies on the isolated LBDs of nuclear receptors established that lipid-ligand binding allosterically regulates the conformation of the LBD, regulating transcriptional coregulator recruitment and thus nuclear receptor function. These structural studies have aided the development of several FDA-approved drugs, highlighting the importance of understanding the structure-function relationships between lipids and nuclear receptors. However, there are few published descriptions of full-length nuclear receptor structure and even fewer descriptions of how lipids might allosterically regulate full-length structure. Here, we examine multidomain interactions based on the published full-length nuclear receptor structures, evaluating the potential of interdomain interfaces within these nuclear receptors to act as inducible sites of allosteric regulation by lipids.

The impact of vitamin D on cancer: A mini review

In this review, we summarize the most recent advances in vitamin D cancer research to provide molecular clarity, as well as its translational trajectory across the cancer landscape. Vitamin D is well known for its role in regulating mineral homeostasis; however, vitamin D deficiency has also been linked to the development and progression of a number of cancer types. Recent epigenomic, transcriptomic, and proteomic studies have revealed novel vitamin D-mediated biological mechanisms that regulate cancer cell self-renewal, differentiation, proliferation, transformation, and death. Tumor microenvironmental studies have also revealed dynamic relationships between the immune system and vitamin D's anti-neoplastic properties. These findings help to explain the large number of population-based studies that show clinicopathological correlations between circulating vitamin D levels and risk of cancer development and death. The majority of evidence suggests that low circulating vitamin D levels are associated with an increased risk of cancers, whereas supplementation alone or in combination with other chemo/immunotherapeutic drugs may improve clinical outcomes even further. These promising results still necessitate further research and development into novel approaches that target vitamin D signaling and metabolic systems to improve cancer outcomes.

Calcitriol Protects against Acetaminophen-Induced Hepatotoxicity in Mice

Acetaminophen (APAP) overdose is one of the major causes of acute liver failure. Severe liver inflammation and the production of oxidative stress occur due to toxic APAP metabolites and glutathione depletion. Growing evidence has proved that vitamin D (VD) exerts anti-inflammatory and antioxidative functions. Our objective was to explore the protective role of calcitriol (VD3) in acute APAP-induced liver injury. Methods: Adult male mice were randomized into three groups; control (n = 8), APAP (n = 8), and VD3 group (n = 8). All mice, except controls, received oral administration of APAP (400 mg/kg) and were sacrificed 24 h later. In the VD3 group, calcitriol (10 µg/kg) was injected intraperitoneally 24 h before and after exposure to APAP. Blood samples were collected to assess serum aminotransferase and inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)]. Liver tissues were analyzed for hepatic glutathione (GSH), malondialdehyde (MDA), and histopathology. Results: APAP administration significantly increased serum aminotransferase, inflammatory cytokines, and induced cellular inflammation and necrosis. APAP also depleted hepatic GSH and elevated oxidative stress, as indicated by high MDA levels. In the APAP group, 25% of the mice (two out of eight) died, while no deaths occurred in the VD3 group. Treatment with calcitriol significantly reduced serum aminotransferase, TNF-α, and IL-6 levels in the VD3 group compared to the APAP group. Additionally, VD3 effectively restored GSH reserves, reduced lipid peroxidation, and attenuated hepatotoxicity. Conclusions: These findings demonstrate that VD3 prevents APAP-induced acute liver injury and reduces mortality in mice through its anti-inflammatory and antioxidative activity. Thus, VD3 might be a novel treatment strategy for APAP-induced hepatotoxicity.

Vitamin D inhibits osteosarcoma by reprogramming nonsense-mediated RNA decay and SNAI2-mediated epithelial-to-mesenchymal transition

Osteosarcomas are immune-resistant and metastatic as a result of elevated nonsense-mediated RNA decay (NMD), reactive oxygen species (ROS), and epithelial-to-mesenchymal transition (EMT). Although vitamin D has anti-cancer effects, its effectiveness and mechanism of action against osteosarcomas are poorly understood. In this study, we assessed the impact of vitamin D and its receptor (VDR) on NMD-ROS-EMT signaling in in vitro and in vivo osteosarcoma animal models. Initiation of VDR signaling facilitated the enrichment of EMT pathway genes, after which 1,25(OH)2D, the active vitamin D derivative, inhibited the EMT pathway in osteosarcoma subtypes. The ligand-bound VDR directly downregulated the EMT inducer SNAI2, differentiating highly metastatic from low metastatic subtypes and 1,25(OH)2D sensitivity. Moreover, epigenome-wide motif and putative target gene analysis revealed the VDR's integration with NMD tumorigenic and immunogenic pathways. In an autoregulatory manner, 1,25(OH)2D inhibited NMD machinery genes and upregulated NMD target genes implicated in anti-oncogenic activity, immunorecognition, and cell-to-cell adhesion. Dicer substrate siRNA knockdown of SNAI2 revealed superoxide dismutase 2 (SOD2)-mediated antioxidative responses and 1,25(OH)2D sensitization via non-canonical SOD2 nuclear-to-mitochondrial translocalization leading to overall ROS suppression. In a mouse xenograft metastasis model, the therapeutically relevant vitamin D derivative calcipotriol inhibited osteosarcoma metastasis and tumor growth shown for the first time. Our results uncover novel osteosarcoma-inhibiting mechanisms for vitamin D and calcipotriol that may be translated to human patients.

Vitamin D inhibits osteosarcoma by reprogramming nonsense-mediated RNA decay and SNAI2-mediated epithelial-to-mesenchymal transition

Osteosarcomas are immune-resistant and metastatic as a result of elevated nonsense-mediated RNA decay (NMD), reactive oxygen species (ROS), and epithelial-to-mesenchymal transition (EMT). Although vitamin D has anti-cancer effects, its effectiveness and mechanism of action against osteosarcomas are poorly understood. In this study, we assessed the impact of vitamin D and its receptor (VDR) on the NMD-ROS-EMT signaling axis in in vitro and in vivo osteosarcoma animal models. Initiation of VDR signaling facilitated the enrichment of EMT pathway genes, after which 1,25(OH) ₂ D, the active vitamin D derivative, inhibited the EMT pathway in osteosarcoma subtypes. The ligand-bound VDR directly downregulated the EMT inducer SNAI2 , differentiating highly metastatic from low metastatic subtypes and 1,25(OH) ₂ D sensitivity. Moreover, epigenome-wide motif and putative target gene analysis revealed the VDR’s integration with NMD tumorigenic and immunogenic pathways. In an autoregulatory manner, 1,25(OH) ₂ D inhibited NMD machinery genes and upregulated NMD target genes implicated in anti-oncogenic activity, immunorecognition, and cell-to-cell adhesion. Dicer substrate siRNA knockdown of SNAI2 revealed superoxide dismutase 2 (SOD2)-mediated antioxidative responses and 1,25(OH) ₂ D sensitization via non-canonical SOD2 nuclear-to-mitochondrial translocalization leading to overall ROS suppression. In a mouse xenograft metastasis model, the therapeutically relevant vitamin D derivative calcipotriol inhibited osteosarcoma metastasis and tumor growth shown for the first time. Our results uncover novel osteosarcoma-inhibiting mechanisms for vitamin D and calcipotriol that may be translated to human patients.

Real-world evidence for the effectiveness of vitamin D supplementation in reduction of total and cause-specific mortality

BACKGROUND

Meta-analyses of randomized controlled trials (RCTs) have demonstrated the efficacy of vitamin D supplementation for reduced cancer mortality, all-cause mortality, and respiratory tract infections. However, whether and to what extent this translates into effectiveness in real-world practice is unknown.

METHODS

We assessed the association of vitamin D supplement use (as an over-the-counter drug or as part of a multivitamin product), vitamin D deficiency (25-hydroxyvitamin D, 25[OH]D <30 nmol/L), and insufficiency (25[OH]D 30 to <50 nmol/L) with all-cause and cause-specific mortality in 445,601 participants, aged 40-73 years, from the UK Biobank cohort.

RESULTS

A total of 4.3% and a further 20.4% of the study participants reported regularly taking vitamin D or multivitamin supplements, respectively. Still, the majority had either vitamin D deficiency (21.0%) or insufficiency (34.3%). We detected 49 independent determinants of vitamin D deficiency and vitamin D supplement use and used them to adjust Cox regression models for all mortality outcomes. A total of 29,107 (6.5%) participants died during a median follow-up time of 11.8 years. Both vitamin D deficiency and insufficiency were strongly associated with all mortality outcomes. Self-reported vitamin D supplement use (83% over-the-counter/17% prescription drugs) and multivitamin intake were significantly associated with 10% and 5% lower all-cause mortality, respectively. Furthermore, regular vitamin D supplement users had 11%, 11%, and 29% lower cancer, cardiovascular disease, and respiratory disease mortality than nonusers, respectively (not significant for cardiovascular disease mortality).

CONCLUSION

This large study suggests that in the real world, the efficacy of vitamin D supplements in reducing mortality may be at least as good as observed in RCTs.

Cell-free SLC30A10 messenger ribonucleic acid (mRNA) expression and their association with vitamin-D level among non-small cell lung cancer (NSCLC) patients

BACKGROUND

Lung cancer has been major cause of cancer related death and day by day Non-small cell lung cancer (NSCLC) cases are increasing globally. Present study explored the link between SLC30A10 mRNA expression with vitamin-D level among the NSCLC patients.

METHODS

Present study included newly diagnosed 100 NSCLC patients and 100 healthy controls. Quantitative real time PCR was performed to check the SLC30A10 mRNA expression after cDNA synthesis from extracted total RNA from serum sample. Vitamin-D level was also analyzed in all the NSCLC patients by electrochemiluminscence based immunoassay method.

RESULTS

Present research work observed decreased SLC30A10 mRNA expression (0.16 fold) among the NSCLC patients, decreased SLC30A10 mRNA expression was linked with advanced stage (0.15 fold, P < 00001) of disease and distant organ metastases (0.11 fold, P < 00001) compared to its contrast. Decreased level of vitamin-D was also observed with advanced stage (17.98 ng/ml, P < 00001) of disease and distant organ metastases (16.23 ng/ml, P < 00001) compared to its contrast. Positive correlation was observed between SLC30A10 mRNA expression with vitamin-D level among the NSCLC patients suggesting decrease or increase in SLC30A10 mRNA expression mau decreases or increase the vitamin-D level. NSCLC patients with vitamin-D deficiency had 0.14 reduced SCL30A10 mRNA expression while insufficient (P = 0 .06) and sufficient (P = 0.03) showed comparatively high SCL30A10 mRNA expression.

CONCLUSION

Study concluded that down regulation of SLC30A10 mRNA and vitamin-D deficiency may involve in advancement of disease and distant organ metastases. It was also suggested that the decrease of increase in SLC30A10 expression may cause the decrease of increase in vitamin-D level among the NSCLC patients may be involved in disease severity and worseness of NSCLC disease.

The relationship between nutrition and the immune system

Nutrition plays an essential role in the regulation of optimal immunological response, by providing adequate nutrients in sufficient concentrations to immune cells. There are a large number of micronutrients, such as minerals, and vitamins, as well as some macronutrients such as some amino acids, cholesterol and fatty acids demonstrated to exert a very important and specific impact on appropriate immune activity. This review aims to summarize at some extent the large amount of data accrued to date related to the modulation of immune function by certain micro and macronutrients and to emphasize their importance in maintaining human health. Thus, among many, some relevant case in point examples are brought and discussed: (1) The role of vitamin A/all-trans-retinoic-acids (ATRA) in acute promyelocytic leukemia, being this vitamin utilized as a very efficient therapeutic agent via effective modulation of the immune function (2) The involvement of vitamin C in the fight against tumor cells via the increase of the number of active NK cells. (3) The stimulation of apoptosis, the suppression of cancer cell proliferation, and delayed tumor development mediated by calcitriol/vitamin D by means of immunity regulation (4) The use of selenium as a cofactor to reach more effective immune response to COVID vaccination (5). The crucial role of cholesterol to regulate the immune function, which is demonstrated to be very sensitive to the variations of this macronutrient concentration. Other important examples are reviewed as well.

Is Season of Diagnosis a Predictor of Cancer Survival? Results from the Zurich Cancer Registry

In Switzerland, there is a large seasonal variation in sunlight, and vitamin D deficiency is relatively common during winter. The season of diagnosis may be linked to cancer survival via vitamin D status. Using data from the Cancer Registry of Zurich, Zug, Schaffhausen, and Schwyz with more than 171,000 cancer cases registered since 1980, we examined the association of the season of diagnosis with survival for cancers including prostate (ICD10 code C61; International Categorization of Diseases, version 10), breast (C50), colorectal (C18-21), lung (C34), melanoma (C43), and all sites combined. Cox proportional hazards regression models were used to assess the differences in the all-cause mortality by the season of the diagnosis. Winter was used as the reference season. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for all the cancers combined (excluding nonmelanoma skin cancer) and for prostate (in men), breast (in women), colorectal, lung cancer, and melanomas, separately. A diagnosis in summer and/or autumn was associated with improved survival in all the sites combined for both sexes (men: HR 0.97 [95% CI 0.96-0.99]; women: HR 0.97 [95% CI 0.94-0.99]) and in colorectal (HR 0.91 [95% CI 0.84-0.99]), melanoma (HR 0.81 [95% CI 0.65-1.00]), and breast cancer (HR 0.91 [95% CI 0.94-0.99]) in women. Our study results suggest that a cancer diagnosis in summer and/or autumn is associated with a better prognosis. The improved seasonal survival coincides with the seasonal variation of sun-induced vitamin D, and vitamin D may play a protective and beneficial role in cancer survival.

In Vitro Angiogenesis Inhibition and Endothelial Cell Growth and Morphology

A co-culture assay with human umbilical vein endothelial cells (HUVECs) and normal human dermal fibroblasts (NHDFs) was used to study whether selected angiogenesis inhibitors were able to inhibit differentiation and network formation of HUVECs in vitro. The effect of the inhibitors was determined by the morphology and the calculated percentage area covered by HUVECs. Neutralizing VEGF with avastin and polyclonal goat anti-VEGF antibody and inhibiting VEGFR2 with sorafenib and vatalanib resulted in the formation of HUVEC clusters of variable sizes as a result of inhibited EC differentiation. Furthermore, numerous inhibitors of the VEGF signaling pathways were tested for their effect on the growth and differentiation of HUVECs. The effects of these inhibitors did not reveal a cluster morphology, either individually or when combined to block VEGFR2 downstream pathways. Only the addition of N-methyl-p-bromolevamisole revealed a similar morphology as when targeting VEGF and VEGFR2, meaning it may have an inhibitory influence directly on VEGFR signaling. Additionally, several nuclear receptor ligands and miscellaneous compounds that might affect EC growth and differentiation were tested, but only dexamethasone gave rise to cluster formation similarly to VEGF-neutralizing compounds. These results point to a link between angiogenesis, HUVEC differentiation and glucocorticoid receptor activation.

Elimination of Vitamin D Signaling Causes Increased Mortality in a Model of Overactivation of the Insulin Receptor: Role of Lipid Metabolism

Vitamin D (VD) deficiency has been associated with cancer and diabetes. Insulin signaling through the insulin receptor (IR) stimulates cellular responses by activating the PI3K/AKT pathway. PTEN is a tumor suppressor and a negative regulator of the pathway. Its absence enhances insulin signaling leading to hypoglycemia, a dangerous complication found after insulin overdose. We analyzed the effect of VD signaling in a model of overactivation of the IR. We generated inducible double KO (DKO) mice for the VD receptor (VDR) and PTEN. DKO mice showed severe hypoglycemia, lower total cholesterol and increased mortality. No macroscopic tumors were detected. Analysis of the glucose metabolism did not show clear differences that would explain the increased mortality. Glucose supplementation, either systemically or directly into the brain, did not enhance DKO survival. Lipidic liver metabolism was altered as there was a delay in the activation of genes related to β-oxidation and a decrease in lipogenesis in DKO mice. High-fat diet administration in DKO significantly improved its life span. Lack of vitamin D signaling increases mortality in a model of overactivation of the IR by impairing lipid metabolism. Clinically, these results reveal the importance of adequate Vitamin D levels in T1D patients.

Vitamin D and Hypoxia: Points of Interplay in Cancer

Vitamin D is a hormone that, through its action, elicits a broad spectrum of physiological responses ranging from classic to nonclassical actions such as bone morphogenesis and immune function. In parallel, many studies describe the antiproliferative, proapoptotic, antiangiogenic effects of calcitriol (the active hormonal form) that contribute to its anticancer activity. Additionally, epidemiological data signify the inverse correlation between vitamin D levels and cancer risk. On the contrary, tumors possess several adaptive mechanisms that enable them to evade the anticancer effects of calcitriol. Such maladaptive processes are often a characteristic of the cancer microenvironment, which in solid tumors is frequently hypoxic and elicits the overexpression of Hypoxia-Inducible Factors (HIFs). HIF-mediated signaling not only contributes to cancer cell survival and proliferation but also confers resistance to anticancer agents. Taking into consideration that calcitriol intertwines with signaling events elicited by the hypoxic status cells, this review examines their interplay in cellular signaling to give the opportunity to better understand their relationship in cancer development and their prospect for the treatment of cancer.

Association between vitamin D supplementation and cancer incidence and mortality: A trial sequential meta-analysis of randomized controlled trials

Observational studies and clinical trials have evaluated the associations between vitamin D supplementation and cancer incidence/mortality and obtained mixed results. Previous meta-analyses have also yielded inconsistent conclusions. In this paper, we conduct an updated meta-analysis by including current randomized clinical trials (RCTs) to assess the association between vitamin D supplementation and cancer incidence and mortality. The PubMed, Scopus and Embase databases were systematically searched from their inception to 6 February 2022. Fixed-effects meta-analyses were conducted. Trial sequential analyses were performed using a risk ratio reduction threshold of 10% for cancer incidence and mortality. Twenty-six RCTs were eligible, and pooled results indicated that vitamin D supplementation, compared to placebo with/without calcium, was not associated with a reduction in total cancer incidence (risk ratio: 0.98, 95% CI: 0.94, 1.02; I2 = 0%). In contrast, vitamin D supplementation significantly reduced total cancer mortality (risk ratio: 0.88, 95% CI: 0.8, 0.96; I2 = 0%). Moreover, trial sequential analysis provided reliable evidence that supplementation with vitamin D lowered the relative risk of total cancer mortality by 10%. Our updated meta-analysis suggested that vitamin D supplementation did not reduce total cancer incidence but significantly lowered total cancer mortality.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2056574 .

Calcifediol (25OH Vitamin D3) Deficiency: A Risk Factor from Early to Old Age

Vitamin D deficiency is the main cause of nutritional rickets in children and osteomalacia in adults. There is consensus that nutritional access to vitamin D can be estimated by measuring serum concentrations of 25OHD and vitamin D deficiency can thus be considered as calcifediol deficiency. However, the threshold for vitamin D/calcifediol sufficiency remains a matter of debate. Vitamin D/calcifediol deficiency has been associated with musculoskeletal effects but also multiple adverse extra-skeletal consequences. If these consequences improve or if they can be treated with vitamin D supplementation is still unclear. Observational studies suggest a higher infection risk in people with low calcifediol levels. There is also a consistent association between serum calcifediol and cardiovascular events and deaths, but large-scale, long-term intervention studies did not show any benefit on cardiovascular outcomes from supplementation, at least not in subjects without clear vitamin D deficiency. Cancer risk also did not change with vitamin D treatment, although there are some data that higher serum calcifediol is associated with longer survival in cancer patients. In pregnant women, vitamin D supplementation decreases the risk of pre-eclampsia, gestational diabetes mellitus, and low birth weight. Although preclinical studies showed that the vitamin D endocrine system plays a role in certain neural cells as well as brain structure and function, there is no evidence to support a beneficial effect of vitamin D in neurodegenerative diseases. Vitamin D supplementation may marginally affect overall mortality risk especially in elderly subjects with low serum calcifediol concentrations.

Role of vitamin D deficiency and comorbidities in COVID-19

Recent manuscripts described the incidence of vitamin D hypovitaminosis in coronavirus disease 2019 (COVID-19) patients. Vitamin D deficiency is also common in patients with comorbidities that are associated with a poor COVID-19 prognosis. In this letter, we review the literature regarding the association of comorbidities, vitamin D deficiency, and COVID-19.

New Approaches to Assess Mechanisms of Action of Selective Vitamin D Analogues

Recent studies of transcription have revealed an advanced set of overarching principles that govern vitamin D action on a genome-wide scale. These tenets of vitamin D transcription have emerged as a result of the application of now well-established techniques of chromatin immunoprecipitation coupled to next-generation DNA sequencing that have now been linked directly to CRISPR-Cas9 genomic editing in culture cells and in mouse tissues in vivo. Accordingly, these techniques have established that the vitamin D hormone modulates sets of cell-type specific genes via an initial action that involves rapid binding of the VDR-ligand complex to multiple enhancer elements at open chromatin sites that drive the expression of individual genes. Importantly, a sequential set of downstream events follows this initial binding that results in rapid histone acetylation at these sites, the recruitment of additional histone modifiers across the gene locus, and in many cases, the appearance of H3K36me3 and RNA polymerase II across gene bodies. The measured recruitment of these factors and/or activities and their presence at specific regions in the gene locus correlate with the emerging presence of cognate transcripts, thereby highlighting sequential molecular events that occur during activation of most genes both in vitro and in vivo. These features provide a novel approach to the study of vitamin D analogs and their actions in vivo and suggest that they can be used for synthetic compound evaluation and to select for novel tissue- and gene-specific features. This may be particularly useful for ligand activation of nuclear receptors given the targeting of these factors directly to genetic sites in the nucleus.

Evaluation of the potential anticancer activity of different vitamin D metabolites on colorectal and breast cancer cell lines

OBJECTIVES

Vitamin D is very important for calcium and mineral metabolism, and many hypotheses appear to link sunlight exposure with cancer risk and prognosis. As many studies supported the antitumor effect of vitamin D we wanted to investigate the potential effect of multiple vitamin D metabolites.

METHODS

This study compared the anticancer effect of three inactive forms of vitamin D₃ which are; cholecalciferol, alfacalcidol, and calcifediol on two human cancer cell lines colorectal cancer (CaCo II) and breast cancer (MCF-7). All were examined after 24, 48, and 72 h continuous exposure using a colorimetric assay (MTT) seeded in 96-multiwell plates. Doxorubicin anticancer used as a standard agent for comparison, while normal skin fibroblast cells (HDFa) was used as our negative control. IC₅₀ values were calculated as indication of antitumor effect.

RESULTS

Broad-spectrum of cytotoxicity with IC₅₀ values ranging from 4 to 200 μM were found. Alfacalcidol was the most potent cytotoxic agents on colorectal cancer (CaCo II) and breast cancer (MCF-7) compared to cholecalciferol, and calcifediol. Both, alfacalcidol and calcifediol were more cytotoxic than cholecalciferol on the tested cell lines as they are partially active metabolites. Breast cancer (MCF-7) was the most sensitive to all metabolites at all-time intervals with the best IC₅₀ values of 4.35 μM ± 1.06 after 72 h continuous exposure of alfacalcidol.

CONCLUSIONS

Vitamin D metabolites are a potential option for cancer treatment along with or an alternative to chemo-therapeutics although extensive preclinical studies are required to prove this effect.

The Association Between the Genetic VDR SNP c.907+75C>T and Prostate Cancer Risk Is Modified by Tanning Potential

BACKGROUND

Prostate cancer (PCa) is a multifactorial disease involving complex interactions between genetic and physiological/environmental factors. Vitamin D receptor (VDR) plays a role in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to PCa.

MATERIALS AND METHODS

Logistic regression analysis was used to assess the association of six VDR single nucleotide polymorphisms (SNPs) and factors such as tanning potential and UV sunlight exposure with PCa risk.

RESULTS

Marginal significant interactions were found, with a 2-fold increase risk of PCa between SNP 1 (c.278-69G>A) and sunlight UV exposure [odds ratio (OR)=2.02, 95% confidence intervaI (CI)=1.036-4.36; p=0.05]; and a 4-fold increase risk of PCa between SNP 4 (c.907+75C>T) and tanning potential (OR=4.40, 95% CI=0.89-29.12; p=0.0591). In contrast, SNP 5 (rs731236, TaqI) and tanning potential interaction had a protective effect by reducing the risk of PCa by 55% (β=-0.804; OR=0.448, 95% CI=0.197-9.42; p=0.0427). SNPs 2 (rs61614328) and 6 (rs533037428) did not show any association with PCa even in the presence of UV sunlight exposure.

CONCLUSION

The protective effect of SNP 4 from PCa is lost and modified by tanning potential in African Americans. This finding needs to be verified by larger studies in different ethnic populations.

Structure-Activity Relationship Study of an Alkynylphosphonate and Vynilphosphonate Analogues of Calcitriol

BACKGROUND

1α,25-dihydroxy vitamin D3 (calcitriol) shows potent growth-inhibitory properties on different cancer cell lines, but its hypercalcemic effects have severely hampered its therapeutic application. Therefore, it is important to develop synthetic calcitriol analogues that retain or even increase its antitumoral effects and lack hypercalcemic activity. Based on previous evidence of the potent antitumor effects of the synthetic alkynylphosphonate EM1 analogue, we have now synthesized a derivative called SG.

OBJECTIVE

The aim of the present work is to evaluate the calcemic activity and the antitumor effect of SG, comparing these effects with those exerted by calcitriol and with those previously published for EM1. In addition, we propose to analyze by in silico studies, the chemical structure-biological function relationship of these molecules.

METHODS

We performed the synthesis of vinylphosphonate SG analogue; in vitro assays on different cancer cell lines; in vivo assays on mice; and in silico assays applying computational molecular modeling.

RESULTS

The SG compound lacks hypercalcemic activity, similar to the parent compound EM1. However, the antitumor activity was blunted, as no antiproliferative or anti-migratory effects were observed. By in silico assays, we demonstrated that SG analogue has a lower affinity for the VDRligand- binding domain than the EM1 compound due to lack of interaction with the important residues His305 and His397.

CONCLUSION

These results demonstrate that the chemical modification in the lateral side chain of the SG analogue affects the antitumoral activity observed previously for EM1 but does not affect the calcemic activity. These results contribute to the rational design and synthesis of novel calcitriol analogues.

The Role of Vitamin D and Sunlight Incidence in Cancer

BACKGROUND

Vitamin D (VD) deficiency affects individuals of different ages in many countries. VD deficiency may be related to several diseases, including cancer.

OBJECTIVE

This study aimed to review the relationship between VD deficiency and cancer.

METHODS

We describe the proteins involved in cancer pathogenesis and how those proteins can be influenced by VD deficiency. We also investigated a relationship between cancer death rate and solar radiation.

RESULTS

We found an increased bladder cancer, breast cancer, colon-rectum cancer, lung cancer, oesophagus cancer, oral cancer, ovary cancer, pancreas cancer, skin cancer and stomach cancer death rate in countries with low sunlight. It was also observed that amyloid precursor protein, ryanodine receptor, mammalian target of rapamycin complex 1, and receptor for advanced glycation end products are associated with a worse prognosis in cancer. While the Klotho protein and VD receptor are associated with a better prognosis in the disease. Nfr2 is associated with both worse and better prognosis in cancer.

CONCLUSION

The literature suggests that VD deficiency might be involved in cancer progression. According to sunlight data, we can conclude that countries with low average sunlight have high cancers death rate. New studies involving transcriptional and genomic data in combination with VD measurement in long-term experiments are required to establish new relationships between VD and cancer.

Single Nucleotide Polymorphisms in 25-Hydroxyvitamin D3 1-Alpha-Hydroxylase (CYP27B1) Gene: The Risk of Malignant Tumors and Other Chronic Diseases

: Vitamin D is widely known for its roles in the promotion of apoptosis and differentiation, with simultaneous inhibition of proliferation, inflammation, angiogenesis, invasion, and metastasis. Modern literature lacks complete information on polymorphisms in CYP27B1, the only enzyme capable of vitamin D activation. This review presents gathered data that relate to genetic variants in CYP27B1 gene in correlation to multiple diseases, mostly concerning colorectal, prostate, breast, lung, and pancreatic cancers, as well as on other pathologies, such as non-Hodgkin's lymphoma, oral lichen planus, or multiple sclerosis.

Genetic Polymorphisms in the Vitamin D Pathway and Non-small Cell Lung Cancer Survival

Various genetic polymorphisms have been linked to lung cancer susceptibility and survival outcomes. Vitamin D (VD) regulates cell proliferation and differentiation, inhibits tumor growth and induces apoptosis. Observations from several previous studies including our own suggest that genetic polymorphisms in the VD pathway may be associated with lung cancer risk. The aim of this study is to assess if genetic polymorphisms in the VD pathway are associated with the prognosis of non-small cell lung cancer (NSCLC). Nine single nucleotide polymorphisms (SNPs) in five genes in the VD pathway were genotyped with the TaqMan assays in 542 patients with primary NSCLC, and the relationships between these SNPs and overall survival were evaluated. We found that SNP rs10741657 in the CYP2R1 gene was associated with the prognosis of NSCLC, especially in elderly patients and not being treated with chemotherapy. Some of the VD pathway-related genetic polymorphisms may influence the prognosis of NSCLC. More research is needed to further confirm the finding and test if VD supplements can be used for NSCLC treatment.

DOX-Vit D, a Novel Doxorubicin Delivery Approach, Inhibits Human Osteosarcoma Cell Proliferation by Inducing Apoptosis While Inhibiting Akt and mTOR Signaling Pathways

Doxorubicin (DOX) is a very potent and effective anticancer agent. However, the effectiveness of DOX in osteosarcoma is usually limited by the acquired drug resistance. Recently, Vitamin D (Vit-D) was shown to suppress the growth of many human cancer cells. Taken together, we synthesized DOX-Vit D by conjugating Vit-D to DOX in order to increase the delivery of DOX into cancer cells and mitigate the chemoresistance associated with DOX. For this purpose, MG63 cells were treated with 10 µM DOX or DOX-Vit D for 24 h. Thereafter, MTT, real-time PCR and western blot analysis were used to determine cell proliferation, genes and proteins expression, respectively. Our results showed that DOX-Vit D, but not DOX, significantly elicited an apoptotic signal in MG63 cells as evidenced by induction of death receptor, Caspase-3 and BCLxs genes. Mechanistically, the DOX-Vit D-induced apoptogens were credited to the activation of p-JNK and p-p38 signaling pathway and the inhibition of proliferative proteins, p-Akt and p-mTOR. Our findings propose that DOX-Vit D suppressed the growth of MG63 cells by inducing apoptosis while inhibiting cell survival and proliferative signaling pathways. DOX-Vit D may serve as a novel drug delivery approach to potentiate the delivery of DOX into cancer cells.

The association between 25(OH)D levels, frailty status and obesity indices in older adults

BACKGROUND

Vitamin D deficiency is common in older adults and has been linked with frailty and obesity, but it remains to be studied whether frail obese older adults are at higher risk of vitamin D deficiency. Therefore, the aim of this study is to explore the association between frailty, obesity indices and serum 25(OH)D concentrations.

METHODS

1447 individuals with 65 years or older, participating in a cross-sectional study (Nutrition UP 65) were included. Frailty, according to Fried et al., body mass index (BMI), waist circumference (WC), body roundness index (BRI) and body shape index (ABSI) were evaluated. A stepwise multinomial logistic regression was carried out to quantify the association between 25(OH)D quartiles and independent variables.

RESULTS

Median 25(OH)D levels were lower in individuals presenting both frailty and obesity (p<0.001). In the multivariate analysis, pre-frailty (OR: 2.65; 95% CI: 1.63-4.33) and frailty (OR: 3.77; 95% CI: 2.08-6.83) were associated with increased odds of lower 25(OH)D serum levels (first quartile). Regarding obesity indices, the highest categories of BMI (OR: 1.74; 95% CI: 1.06-2.86), WC (OR: 3.46; 95% CI: 1.95-6.15), BRI (OR: 4.35; 95% CI: 2.60-7.29) and ABSI (OR: 3.17 95% CI: 1.86-5.38) were directly associated with lower 25(OH)D serum levels (first quartile).

CONCLUSIONS

A positive association between frailty or obesity and lower vitamin D levels was found. Moreover, besides BMI and WC, other indicators of body adiposity, such as BRI and ABSI, were associated with lower 25(OH)D serum concentrations.

Vitamin D and the Liver-Correlation or Cause?

Vitamin D is becoming increasingly accepted as an important physiological regulator outside of its classical role in skeletal homeostasis. A growing body of evidence connects vitamin D with hepatic disease. This review summarises the role of vitamin D in liver homeostasis and disease and discusses the therapeutic potential of vitamin D-based treatments to protect against hepatic disease progression and to improve response to treatment. While pre-clinical experimental data is promising, clinical trials around liver diseases have mostly been under-powered, and further studies will be required to clarify whether vitamin D or vitamin D analogues have beneficial effects on liver disease.

Association of rs2282679 A>C polymorphism in vitamin D binding protein gene with colorectal cancer risk and survival: effect modification by dietary vitamin D intake

Background

The rs2282679 A>C polymorphism in the vitamin D binding protein gene is associated with lower circulating levels of vitamin D. We investigated associations of this SNP with colorectal cancer (CRC) risk and survival and whether the associations vary by dietary vitamin D intake and tumor molecular phenotype.

Methods

A population-based case-control study identified 637 incident CRC cases (including 489 participants with follow-up data on mortality end-points) and 489 matched controls. Germline DNA samples were genotyped with the Illumina Omni-Quad 1 Million chip in cases and the Affymetrix Axiom® myDesign™ Array in controls. Logistic regression examined the association between the rs2282679 polymorphism and CRC risk with inclusion of potential confounders. Kaplan-Meier curves and multivariable Cox models assessed the polymorphism relative to overall survival (OS) and disease-free survival (DFS).

Results

The rs2282679 polymorphism was not associated with overall CRC risk; there was evidence, however, of effect modification by total vitamin D intake (P_interaction = 0.019). Survival analyses showed that the C allele was correlated with poor DFS (per-allele HR, 1.36; 95%CI, 1.05–1.77). The association of rs2282679 on DFS was limited to BRAF wild-type tumors (HR, 1.58; 95%CI, 1.12–2.23). For OS, the C allele was associated with higher all-cause mortality among patients with higher levels of dietary vitamin D (HR, 2.11; 95%CI, 1.29–3.74), calcium (HR, 1.93; 95%CI, 1.08–3.46), milk (HR, 2.36; 95%CI, 1.26–4.44), and total dairy product intakes (HR, 2.03; 95%CI, 1.11–3.72).

Conclusion

The rs2282679 SNP was not associated with overall CRC risk, but may be associated with survival after cancer diagnosis. The association of this SNP on survival among CRC patients may differ according to dietary vitamin D and calcium intakes and according to tumor BRAF mutation status.

Regulation of Immune Function by Vitamin D and Its Use in Diseases of Immunity

Evidence exists for a role for vitamin D and its active metabolites in modulating immune functions. In animal models, vitamin D deficiency is associated with a higher risk for autoimmunity in genetically predisposed subjects and increases in susceptibility to infections. In addition, high-dose vitamin D can improve immune health, prevent autoimmunity, and improve defense against infections. In humans, evidence exists on associations between vitamin D deficiency and impaired immune function, leading to autoimmunity in genetically predisposed people and increased risk for infections; data on therapeutic immune effects of vitamin D supplementation when vitamin D levels are already sufficient are lacking.

Structural aspects of Vitamin D endocrinology

1α,25-Dihydroxvitamin D₃ (1,25(OH)₂D₃) is the hormonally active form of vitamin D₃. Its synthesis and its metabolites, their transport and elimination as well as action on transcriptional regulation involves the harmonic cooperation of diverse proteins with vitamin D binding capacities such as vitamin D binding protein (DBP), cytochrome P450 enzymes or the nuclear vitamin receptor (VDR). The genomic mechanism of 1,25(OH)₂D₃ action involves its binding to VDR that functionally acts as a heterodimer with retinoid X receptor. The crystal structures of the most important proteins for vitamin D₃, VDR, DBP, CYP2R1 and CYP24A1, have provided identification of mechanisms of actions of these proteins and those mediating VDR-regulated transcription. This review will present the structural information on recognition of the vitamin D₃ and metabolites by CYP proteins and DBP as well as the structural basis of VDR activation by 1,25(OH)₂D₃ and metabolites. Additionally, we will describe, the implications of the VDR mutants associated with hereditary vitamin D-resistant rickets (HVDRR) that display impaired function.

Meta-analysis of the correlation between vitamin D and lung cancer risk and outcomes

In this meta-analysis, we analyzed the association between vitamin D levels and lung carcinoma risk and outcomes. Two authors independently searched the Web of Science, Pubmed, EBSCO and Ovid MEDLINE resources with the key words “vitamin D, lung cancer, solar and latitude” and enrolled 22 studies that satisfied the inclusion criteria. The summary odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the random (or fixed)-effects model. Potential confounders were carefully adjusted. High vitamin D (or calcium) intake and serum 25(OH)D levels each correlated inversely with lung cancer risk [OR = 0.72 (95% CI: 0.61–0.85, p < 0.001) and OR = 0.89 (95% CI: 0.83–0.97, p < 0.05)]. High circulating 25(OH)D levels also reduced lung cancer mortality with the pooled OR reached 0.39 (95% CI: 0.28–0.54, p < 0.001)]. A positive trend was presented in the relationship between serum 25(OH) D and survival (OR = 1.01, 95% CI: 0.87–1.18, p = 0.87). Subgroup analysis revealed that nonsmokers had higher vitamin D levels, which correlated negatively with lung cancer risk (OR = 0.76, 95% CI: 0.65–0.88, p < 0.01). Moreover, lower sun exposure and high latitude associated with lower vitamin D levels. This meta-analysis shows that high vitamin D (or calcium) intake and serum 25(OH)D levels correlate with lower lung cancer risk and better prognosis. UVB and latitude may play a vital role in lung cancer occurrence and progression, although a direct evidence hasn't been obtained.

Incidence of hematologic malignancy and cause-specific mortality in the Women's Health Initiative randomized controlled trial of calcium and vitamin D supplementation

BACKGROUND

Prior evidence of a possible link between vitamin D status and hematologic malignancy (HM) in humans comes from observational studies, leaving unresolved the question of whether a true causal relationship exists.

METHODS

The authors performed a secondary analysis of data from the Women's Health Initiative Calcium/Vitamin D (CaD) trial, a large randomized controlled trial of CaD supplementation compared with placebo in older women. Kaplan-Meier and Cox proportional hazards survival analysis methods were used to evaluate the relationship between treatment assignment and 1) incident HM and 2) HM-specific mortality over 10 years following randomization. HMs were classified by cell type (lymphoid, myeloid, or plasma cell) and analyzed as distinct endpoints in secondary analyses.

RESULTS

A total of 34,763 Women's Health Initiative CaD trial participants (median age, 63 years) had complete baseline covariate data and were eligible for analysis. Women assigned to CaD supplementation had a significantly lower risk of incident HM (hazard ratio [HR], 0.80; 95% confidence interval [95% CI], 0.65-0.99) but not HM-specific mortality (HR, 0.77 [95% CI, 0.53-1.11] for the entire cohort; and HR, 1.03 [95% CI, 0.70-1.51] among incident HM cases after diagnosis). In secondary analyses, protective associations were found to be most robust for lymphoid malignancies, with HRs of 0.77 (95% CI, 0.59-1.01) and 0.46 (95% CI, 0.24-0.89), respectively, for cancer incidence and mortality in those assigned to CaD supplementation.

CONCLUSIONS

The current post hoc analysis of data from a large and well-executed randomized controlled trial demonstrates a protective association between modest CaD supplementation and HM risk in older women. Additional research concerning the relationship between vitamin D and HM is warranted. Cancer 2017;123:4168-4177. © 2017 American Cancer Society.

The effect of vitamin concentrates on the flavor of pasteurized fluid milk

Fluid milk consumption in the United States continues to decline. As a result, the level of dietary vitamin D provided by fluid milk in the United States diet has also declined. Undesirable flavor(s)/off flavor(s) in fluid milk can negatively affect milk consumption and consumer product acceptability. The objectives of this study were to identify aroma-active compounds in vitamin concentrates used to fortify fluid milk, and to determine the influence of vitamin A and D fortification on the flavor of milk. The aroma profiles of 14 commercial vitamin concentrates (vitamins A and D), in both oil-soluble and water-dispersible forms, were evaluated by sensory and instrumental volatile compound analyses. Orthonasal thresholds were determined for 8 key aroma-active compounds in skim and whole milk. Six representative vitamin concentrates were selected to fortify skim and 2% fat pasteurized milks (vitamin A at 1,500-3,000 IU/qt, vitamin D at 200-1,200 IU/qt, vitamin A and D at 1,000/200-6,000/1,200 IU/qt). Pasteurized milks were evaluated by sensory and instrumental volatile compound analyses and by consumers. Fat content, vitamin content, and fat globule particle size were also determined. The entire experiment was done in duplicate. Water-dispersible vitamin concentrates had overall higher aroma intensities and more detected aroma-active compounds than oil-soluble vitamin concentrates. Trained panelists and consumers were able to detect flavor differences between skim milks fortified with water-dispersible vitamin A or vitamin A and D, and unfortified skim milks. Consumers were unable to detect flavor differences in oil-soluble fortified milks, but trained panelists documented a faint carrot flavor in oil-soluble fortified skim milks at higher vitamin A concentrations (3,000-6,000 IU). No differences were detected in skim milks fortified with vitamin D, and no differences were detected in any 2% milk. These results demonstrate that vitamin concentrates may contribute to off flavor(s) in fluid milk, especially in skim milk fortified with water-dispersible vitamin concentrates.

Association Between Serum Vitamin D and All-Cause and Cause-Specific Death in a General Japanese Population - The Hisayama Study

BACKGROUND

Few studies have investigated the association between serum vitamin D levels and mortality in general Asian populations.Methods and Results:We examined the association of serum 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels with the risk of all-cause and cause-specific death in an average 9.5-year follow-up study of 3,292 community-dwelling Japanese subjects aged ≥40 years (2002-2012). The multivariable-adjusted hazard ratio (HR) for all-cause death increased significantly with lower serum 1,25(OH)₂D levels (HR 1.54 [95% confidence interval, 1.18-2.01] for the lowest quartile, 1.31 [0.99-1.73] for the 2nd quartile, 0.94 [0.70-1.25] for the 3rd quartile, 1.00 [Ref.] for highest quartile; P for trend <0.001). A similar association was observed for cardiovascular and respiratory infection death (both P for trend <0.01), but not for cancer death or death from other causes. In the stratified analysis, the association between lower serum 1,25(OH)₂D levels and the risk of respiratory infection death was stronger in subjects with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m²than in those with eGFR ≥60 mL/min/1.73 m²; there was a significant heterogeneity in the association between eGFR levels (P for heterogeneity=0.04).

CONCLUSIONS

The findings suggested that a lower serum 1,25(OH)₂D level is a potential risk factor for all-cause death, especially cardiovascular and respiratory infection death, in the general Japanese population, and that lower serum 1,25(OH)₂D levels greatly increase the risk of respiratory infection death in subjects with kidney dysfunction.

Vitamin Fortification of Fluid Milk

Vitamin concentrates with vitamins A and D are used for fortification of fluid milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off-flavor(s) in vitamin fortified milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of fluid milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in fluid milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of fluid milk.

Vitamin D in hematological disorders and malignancies

Commonly known for its critical role in calcium homeostasis and bone mineralization, more recently vitamin D has been implicated in hematological cancer pathogenesis and shows promise as an anti-cancer therapy. Serum levels of 25(OH)D₃ , the precursor to the active form of vitamin D, calcitriol, are frequently lower in patients with hematological disease compared to healthy individuals. This often correlates with worse disease outcome. Furthermore, diseased cells typically highly express the vitamin D receptor, which is required for many of the anti-cancer effects observed in multiple in vivo and in vitro cancer models. In abnormal hematological cells, vitamin D supplementation promotes apoptosis, induces differentiation, inhibits proliferation, sensitizes tumor cells to other anti-cancer therapies, and reduces the production of pro-inflammatory cytokines. Although the dosage of vitamin D required to achieve these effects may induce hypercalcemia in humans, analogs and combinatorial treatments have been developed to circumvent this side effect. Vitamin D and its analogs are well tolerated in clinical trials, and thus, further investigation into the use of these agents in the clinic is warranted. Here, we review the current literature in this field.

Fecal Metabolome in Hmga1 Transgenic Mice with Polyposis: Evidence for Potential Screen for Early Detection of Precursor Lesions in Colorectal Cancer

Because colorectal cancer (CRC) remains a leading cause of cancer mortality worldwide, more accessible screening tests are urgently needed to identify early stage lesions. We hypothesized that highly sensitive, metabolic profile analysis of stool samples will identify metabolites associated with early stage lesions and could serve as a noninvasive screening test. We therefore applied traveling wave ion mobility mass spectrometry (TWIMMS) coupled with ultraperformance liquid chromatography (UPLC) to investigate metabolic aberrations in stool samples in a transgenic model of premalignant polyposis aberrantly expressing the gene encoding the high mobility group A (Hmga1) chromatin remodeling protein. Here, we report for the first time that the fecal metabolome of Hmga1 mice is distinct from that of control mice and includes metabolites previously identified in human CRC. Significant alterations were observed in fatty acid metabolites and metabolites associated with bile acids (hypoxanthine xanthine, taurine) in Hmga1 mice compared to controls. Surprisingly, a marked increase in the levels of distinctive short, arginine-enriched, tetra-peptide fragments was observed in the transgenic mice. Together these findings suggest that specific metabolites are associated with Hmga1-induced polyposis and abnormal proliferation in intestinal epithelium. Although further studies are needed, these data provide a compelling rationale to develop fecal metabolomic analysis as a noninvasive screening tool to detect early precursor lesions to CRC in humans.

Vitamin D status of Icelandic children and its influence on bone accrual

The importance of vitamin D for children's bone health has been well established, but the effects of less severe deficiency are not fully known. The main objective of this study was to assess the vitamin D status of Icelandic children at the age of 7, and again at 9 years of age, and the association of vitamin D status with bone mineral content and bone accrual over 2 years. We invited 321 children to participate in this study, and 267 (83 %) took part; 211 (79 %) underwent a DXA scan and 164 were again scanned 2 years later; 159 (60 %) vitamin D samples were measured and 119 (75 %) were measured again 2 years later. At age 7, 65 % of the children had vitamin D concentrations <50 nmol/l, and at age 9 this figure was 60 %. At age 7, 43 % of the children had insufficient amounts of vitamin D (37.5-50 nmol/l), and 22 % had a vitamin D deficiency (<37.5 nmol/l). In linear regression analysis, no association was found between vitamin D and bone mineral content. Furthermore, there was no significant difference in bone accrual over 2 years for the children with insufficient or deficient vitamin D at both ages, compared to those having more than 50 nmol/l at both time points. More than 60 % of Icelandic children have inadequate concentrations of vitamin D in serum repeatedly over a 2-year interval. However, vitamin D in the range did not have a significant effect on bone mineral content or accrual at ages 7 and 9.

Vitamin D machinery and metabolism in porcine adipose-derived mesenchymal stem cells

BACKGROUND

Vitamin D, a hormone once thought to have a role limited to calcium homeostasis and bone mineralization, has pleiotropic effects on different types of cells. Vitamin D receptors are reported in vascular smooth muscle cells, endothelial cells, and cardiomyocytes. Adipose-derived MSCs (ADMSCs) are multipotent cells with the capacity to differentiate into cells of different lineages. To our knowledge, the presence of vitamin D machinery on porcine ADMSCs has not yet been examined. In this study, we investigated the presence of vitamin D machinery and metabolism in ADMSCs by analyzing the expression levels of vitamin D receptor (VDR), vitamin D metabolizing enzymes (CYP24A1 and CYP27B1) after in vitro stimulation with active vitamin D, calcitriol.

METHODS AND RESULTS

ADMSCs isolated from porcine adipose tissue were characterized by positive staining for ADMSC markers, CD44, CD73, and CD90, and negative staining for macrophage marker CD11b and hematopoietic stem cell markers CD34 and CD45, and trilineage differentiation to osteocytes, chondrocytes, and adipocytes. No cytotoxicity was observed when MSCs were stimulated with 0.1-10 nM calcitriol. The ADMSCs were analyzed for mRNA and protein expression of CYP24A1, CYP27B1, and VDR by immunostaining, qPCR, and ELISA. A significant increase (p <0.01) in the mRNA expression of CYP24A1, CYP27B1, and VDR was observed after stimulation of ADMSCs with calcitriol (10 nM). The in vitro time-dependent effect of calcitriol (10 nM) on the components of vitamin D machinery in cultured MSCs was determined by qPCR. The VDR and CYP27B1 expression peaked at 3 h and CYP24A1 at 24 h, respectively. The in vitro biosynthesis of 1, 25(OH)2D3 by ADMSCs was analyzed by ELISA and Western blot. The levels of the active form of vitamin D were significantly decreased once the CYP enzymes were inhibited (p <0.01), demonstrating the ability of ADMSCs to convert inactive vitamin D into active vitamin D for cellular action.

CONCLUSIONS

Porcine ADMSCs possess vitamin D hydrolases and VDR to metabolize and respond to vitamin D. Hence, in vivo circulating 25-hydroxy vitamin D levels may have a significant role in regulating the differentiation of ADMSCs into different lineages, which might assist in stem cell-based therapy.

Protective effects of vitamin D3 on fimbrial cells exposed to catalytic iron damage

Background

Recently, vitamin D₃ (1alpha, 25-dihydroxyvitamin D) has shown its capability to take part in many extraskeletal functions and its serum levels have been related to patient survival rate and malignancy of many types of neoplasms, including ovarian cancers. Catalytic iron is a free circulating form of iron that is able to generate reactive oxygen species and consequently to promote a number of cellular and tissutal dysfunctions including tumorigenesis. In fertile women an important source of catalytic iron is derived from retrograde menstruation. Epithelial secretory cells from fimbriae of fallopian tubes are greatly exposed to catalytic iron derived from menstrual reflux and so represent the site of origin for most serous ovarian cancers.

The aim of this study was to assess whether vitamin D₃ can play a role in counteracting catalytic iron-induced oxidative stress in cells from fimbriae of fallopian tubes.

Methods

The cells, isolated from women undergoing isteroannessiectomy, were treated with catalytic iron 50-75-100 mM and vitamin D₃ at a concentration ranging from 0.01 to 10 nM to study cell viability, radical oxygen species production, p53, pan-Ras, Ki67 and c-Myc protein expressions through Western Blot, and immunocytochemistry or immunofluorescence analysis.

Results

The pre-treatment with vitamin D₃ 1 nM showed its beneficial effects that consists in a significant decrease in ROS production. In addition a novel finding is represented by the demonstration that pre-treatment with vitamin D₃ is also able to significantly counteract tumoral biomarkers activation, such as p53, pan-Ras, Ki67 and c-Myc, and consequently the catalytic iron-induced cellular injury.

Conclusions

This study demonstrates for the first time that vitamin D₃ plays an important role in preventing catalytic iron-dependent oxidative stress in cultured fimbrial cells. These results support the hypothesis that vitamin D₃ could counteract carcinogenic changes induced by catalytic iron.

Nucleotide Excision Repair and Vitamin D--Relevance for Skin Cancer Therapy

Ultraviolet (UV) radiation is involved in almost all skin cancer cases, but on the other hand, it stimulates the production of pre-vitamin D3, whose active metabolite, 1,25-dihydroxyvitamin D3 (1,25VD3), plays important physiological functions on binding with its receptor (vitamin D receptor, VDR). UV-induced DNA damages in the form of cyclobutane pyrimidine dimers or (6-4)-pyrimidine-pyrimidone photoproducts are frequently found in skin cancer and its precursors. Therefore, removing these lesions is essential for the prevention of skin cancer. As UV-induced DNA damages are repaired by nucleotide excision repair (NER), the interaction of 1,25VD3 with NER components can be important for skin cancer transformation. Several studies show that 1,25VD3 protects DNA against damage induced by UV, but the exact mechanism of this protection is not completely clear. 1,25VD3 was also shown to affect cell cycle regulation and apoptosis in several signaling pathways, so it can be considered as a potential modulator of the cellular DNA damage response, which is crucial for mutagenesis and cancer transformation. 1,25VD3 was shown to affect DNA repair and potentially NER through decreasing nitrosylation of DNA repair enzymes by NO overproduction by UV, but other mechanisms of the interaction between 1,25VD3 and NER machinery also are suggested. Therefore, the array of NER gene functioning could be analyzed and an appropriate amount of 1.25VD3 could be recommended to decrease UV-induced DNA damage important for skin cancer transformation.

Genetic polymorphisms in the vitamin D pathway in relation to lung cancer risk and survival

Studies have suggested that vitamin D may have protective effects against cancer development or tumor progression. To search for additional evidence, we investigated the role of genetic polymorphisms involved in the vitamin D pathway in non-small cell lung cancer (NSCLC). We evaluated common genetic polymorphisms associated with the vitamin D pathway in relation to NSCLC in a case-control study of 603 newly diagnosed NSCLC patients and 661 matched healthy controls. Seven single nucleotide polymorphisms (SNPs) were genotyped, the expression of CYP27B1 and CYP24A1 were measured in 153 tumor samples and their associations with genotypes and patient survival were also analyzed. In the case-control comparison, we found SNP rs3782130 (CYP27B1), rs7041 (GC), rs6068816 and rs4809957 (CYP24A1) associated with NSCLC risk. The risk of NSCLC was increased with the number of risk alleles. CYP27B1 and CYP24A1 expression were significantly different between tumor and normal tissues in NSCLC. High CYP27B1 expression was associated with better overall survival, and the expression was different by the rs3782130 genotype. The study suggests that some genetic polymorphisms involved in the vitamin D pathway may associate with NSCLC risk, and one of the polymorphisms (rs3782130) may affect gene expression and patient survival.

Structural Studies of Vitamin D Nuclear Receptor Ligand-Binding Properties

The vitamin D nuclear receptor (VDR) and its natural ligand, 1α,25-dihydroxyvitamin D3 hormone (1,25(OH)2D3, or calcitriol), classically regulate mineral homeostasis and metabolism but also much broader range of biological functions, such as cell growth, differentiation, antiproliferation, apoptosis, adaptive/innate immune responses. Being widely expressed in various tissues, VDR represents an important therapeutic target in the treatment of diverse disorders. Since ligand binding is a key step in VDR-mediated signaling, numerous 1,25(OH)2D3 analogs have been synthesized in order to selectively modulate the receptor activity. Most of the synthetic analogs have been developed by modification of a parental compound and some of them mimic 1,25(OH)2D3 scaffold without being structurally related to it. The ability of ligands that have different size and conformation to bind to VDR and to demonstrate biological effects is intriguing, and therefore, ligand-binding properties of the receptor have been extensively investigated using a variety of biochemical, biophysical, and computational methods. In this chapter, we describe different aspects of the structure-function relationship of VDR in complex with natural and synthetic ligands coming from structural analysis. With the emphasis on the binding modes of the most promising compounds, such as secosteroidal agonists and 1,25(OH)2D3 mimics, we also highlight the action of VDR antagonists and the evidence for the existence of an alternative ligand-binding site within the receptor. Additionally, we describe the crystal structures of VDR mutants associated with hereditary vitamin D-resistant rickets that display impaired ligand-binding function.

Vitamins in pancreatic cancer: a review of underlying mechanisms and future applications

Although there is increasing evidence that vitamins influence pancreatic adenocarcinoma biology and carcinogenesis, a comprehensive review is lacking. In this study, we performed a PubMed literature search to review the anticancer mechanisms and the preclinical and clinical studies that support the development of the bioactive vitamins A, C, D, E, and K in pancreatic cancer intervention. Preclinical studies have shown promising results for vitamin A in pancreatic cancer prevention, with clinical trials showing intriguing responses in combination with immunotherapy. For vitamin C, preclinical studies have shown slower tumor growth rates and/or increased survival when used alone or in combination with gemcitabine, with clinical trials with this combination revealing decreased primary tumor sizes and improved performance status. Preclinical studies with vitamin D analogues have shown potent antiproliferative effects and repression of migration and invasion of pancreatic cancer cells, with a clinical trial showing increased time to progression when calciferol was added to docetaxel. For vitamin E, preclinical studies have shown that δ-tocotrienol and γ-tocotrienol inhibited tumor cell growth and survival and augmented gemcitabine activity. Early-phase clinical trials with δ-tocotrienol are ongoing. Vitamin K demonstrates activation of apoptosis and inhibition of cellular growth in pancreatic tumor cells; however, there are no clinical studies available for further evaluation. Although preclinical and clinical studies are encouraging, randomized controlled trials with endpoints based on insights gained from mechanistic and preclinical studies and early-phase clinical trials are required to determine the efficacy of bioactive vitamin interventions in pancreatic cancer.

Genetic and environmental influences on plasma vitamin D binding protein concentrations

Recent studies suggest that low vitamin D-binding protein (VDBP aka group-specific complement or Gc) concentrations may be linked with inflammatory-mediated conditions, including asthma, chronic obstructive pulmonary disease, and cancer. However, these studies may be confounded by substantial racial and ethnic or genetic differences. The purpose of this study was to test the hypothesis that circulating VDBP concentrations are significantly associated with genetic ancestry. We used a validated high-performance liquid chromatography tandem mass spectrometry assay of 25-hydroxyvitamin D3 and its downstream metabolite 24,25-dihydroxyvitamin D3. VDBP concentrations (milligrams per liter) were measured in duplicate using a commercial enzyme-linked immunosorbent assay among healthy African American (n = 56) and Caucasian American (n = 60) participants. Ancestry informative markers across the genome were used to estimate individual genetic ancestry proportions, designed to robustly distinguish between West African and European ancestry. Genotype-defined Gc isoforms were defined using rs7041 and rs4588 combination groups. VDBP concentration was correlated with both Gc isoform (r = 0.93, P < 0.001) and West African genetic ancestry (r = -0.66, P < 0.001). In the final model, Gc isoform, the catabolic ratio of serum vitamin D, oral contraceptive use, and body mass index remained significantly associated with VDBP concentration, after adjustment for genetic ancestry. Failure to adjust for Gc isoform may lead to spurious associations in studies of VDBP concentration and disease risk, particularly when the condition of interest may also be associated with genetic ancestry. The higher circulating VDBP concentrations and higher vitamin D catabolic rate among Caucasian Americans observed here appear to be consistent with lower bone mineral density and racial and ethnic differences in vitamin D-inducing cytokines.