Pancreatic cancer cells express 25-hydroxyvitamin D-1 alpha-hydroxylase and their proliferation is inhibited by the prohormone 25-hydroxyvitamin D3

The association between circulating 25-hydroxyvitamin D and pancreatic cancer: a systematic review and meta-analysis of observational studies

PURPOSE

The relationship between circulating 25-hydroxyvitamin D [25(OH)D] and pancreatic cancer has been well studied but remains unclear. The purpose of this study was to elucidate the association between circulating 25(OH)D and pancreatic cancer by using a meta-analytic approach.

METHODS

PubMed, Embase, and Wed of Science databases were searched through October 15, 2022. A random or fixed-effects model was used to estimate the pooled odds ratio (OR), risk ratio (RR), hazard ratio (HR) and their 95% confidence intervals (CIs).

RESULTS

A total of 16 studies including 529,917 participants met the inclusion criteria, of which 10 reported incidence and 6 reported mortality. For the highest versus lowest categories of circulating 25(OH)D, the pooled OR of pancreatic cancer incidence in case-control studies was 0.98 (95% CI 0.69-1.27), and the pooled HRs of pancreatic cancer mortality in cohort and case-control studies were 0.64 (95% CI 0.45-0.82) and 0.78 (95% CI 0.62-0.95), respectively. The leave-one-out sensitivity analyses found no outliers and Galbraith plots indicated no substantial heterogeneity.

CONCLUSION

Evidence from this meta-analysis suggested that high circulating 25(OH)D levels may be associated with decreased mortality but not incidence of pancreatic cancer. Our findings may provide some clues for the treatment of pancreatic cancer and remind us to be cautious about widespread vitamin D supplementation for the prevention of pancreatic cancer.

Expression of vitamin D receptor, CYP24A1, and CYP27B1 in normal and inflamed canine pancreases

Vitamin D plays a role in anti-inflammatory processes, and the alteration of its metabolism is associated with the inflammatory processes of pancreatitis. This study was performed to evaluate the expression of the vitamin D receptor (VDR) and the two major enzymes that regulate vitamin D metabolism, 1α-hydroxylase (CYP27B1) and 24-hydroxylase (CYP24A1), in the canine pancreas and to compare their degrees of immunoreactivity between normal and inflamed pancreases. Five normal and inflamed pancreatic tissues each were obtained from six dogs. The expression of VDR, CYP24A1, and CYP27B1 were determined immunohistochemically, and the degree of immunostaining was assessed semiquantitatively. The VDR was expressed in the ducts, acini, and islets of Langerhans of normal pancreases and in the ducts and acini of inflamed ones. There was a significant difference in the immunoreactivity score for VDR in the islets of Langerhans between normal (median, 3 [interquartile range, 2-7.5] score) and inflamed pancreatic tissues (0 [0-0.5] score, p = 0.03). CYP24A1 was expressed in the ducts and islets of Langerhans in both normal and inflamed pancreases, whereas CYP27B1 was expressed in the ducts and acini in only some normal and inflamed pancreatic tissues. This study showed that VDR expression decreased in inflamed pancreases and demonstrated CYP24A1 and CYP27B1 expression in the canine pancreas for the first time. These findings indicate that the pancreas could regulate the metabolism and biological activity of vitamin D and suggest that a decrease in these might be related to the pathophysiology of pancreatitis.

Fat-Soluble Vitamin Deficiencies and Disruption of the Immune System in Pancreatic Cancer: A Vicious Cycle

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is currently an increasing contributor to cancer-related mortality. Despite advances in cancer treatment, PDAC survival rates have remained roughly unchanged over the years. Specifically, late diagnosis and insensitivity to currently available therapeutic regimens have been identified as the main causes for its poor survival. Pancreatic exocrine insufficiency (PEI) is a typical complication associated with PDAC diagnosis and pancreatic surgery. Pancreatic exocrine insufficiency, a major contributor to maldigestion in PDAC, is often not treated because it remains undetected because of lack of overt signs and symptoms. In this review, we will focus on the major consequences of PEI, including the inadequacy of lipase excretion, which results in deficiency of fat-soluble vitamins. Because PDAC is known for its immune-high jacking mechanisms, we describe key features in which deficiencies of fat-soluble vitamins may contribute to the aggressive biological behavior and immune evasion in PDAC. Because PEI has been shown to worsen survival rates in patients with PDAC, detecting PEI and the related fat-soluble vitamin deficits at the time of PDAC diagnosis is critical. Moreover, timely supplementation of pancreatic enzymes and fat-soluble vitamins may improve outcomes for PDAC patients.

Association between deficient levels of circulating vitamin D, dietary intake of vitamin D, calcium and retinol, and risk of colorectal cancer in an Iranian population: A case control study

AIM

We aimed to assess the association between deficient levels of circulating vitamin D, dietary intake of vitamin D, calcium and retinol, and risk of colorectal cancer in an Iranian population.

METHODS

In this retrospective case-control study that was conducted between 2012 and 2015, 278 first incident colorectal cancer cases (colon cancer = 103; rectal cancer = 175), and 278 sex and age matched healthy controls (HCs) were recruited. Serum 25(OH)D, dietary vitamin D, and calcium intake were assessed. Logistic regression was used to estimate the odds ratio (OR) between studied factors and colorectal cancer. Estimates of OR were calculated according to both bivariate analyses based on the matching factors and multivariate analyses, with additional adjustment for potential confounders.

RESULTS

A strong inverse linear dose-response association was seen between serum 25(OH)D and colorectal cancer (P for trend = .002). In comparison to serum 25(OH)D more than 40 nmol/L, lower serum concentrations were significantly associated with an increased OR of colorectal cancer. When analyzing anatomical subsites separately, lower circulating 25(OH)D was associated with higher OR for both colon and rectum cancers. Dietary vitamin D and calcium intake were not associated with colorectal cancer. Interaction analysis between serum 25(OH)D and the amount of calcium intake demonstrated that the lowest level of both factors was associated with an increased OR of colorectal cancer. The highest OR of colorectal cancer that was associated with lowest circulating 25(OH)D was stronger at the highest retinol intakes.

CONCLUSION

This study demonstrated an inverse strong association between 25(OH)D concentration and colorectal cancer in an Iranian population.

Policing Cancer: Vitamin D Arrests the Cell Cycle

Vitamin D is a steroid hormone crucial for bone mineral metabolism. In addition, vitamin D has pleiotropic actions in the body, including anti-cancer actions. These anti-cancer properties observed within in vitro studies frequently report the reduction of cell proliferation by interruption of the cell cycle by the direct alteration of cell cycle regulators which induce cell cycle arrest. The most recurrent reported mode of cell cycle arrest by vitamin D is at the G1/G0 phase of the cell cycle. This arrest is mediated by p21 and p27 upregulation, which results in suppression of cyclin D and E activity which leads to G1/G0 arrest. In addition, vitamin D treatments within in vitro cell lines have observed a reduced C-MYC expression and increased retinoblastoma protein levels that also result in G1/G0 arrest. In contrast, G2/M arrest is reported rarely within in vitro studies, and the mechanisms of this arrest are poorly described. Although the relationship of epigenetics on vitamin D metabolism is acknowledged, studies exploring a direct relationship to cell cycle perturbation is limited. In this review, we examine in vitro evidence of vitamin D and vitamin D metabolites directly influencing cell cycle regulators and inducing cell cycle arrest in cancer cell lines.

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

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

Vitamin D and Gastrointestinal Cancers: A Narrative Review

Calcitriol (1,25(OH)₂D₃) performs various activities throughout the body. Although low serum 25-hydroxyvitamin D [25(OH)D] levels are associated with several disease processes such as risk of fractures and falls, hypertension, cardiovascular disease, and diabetes mellitus, recent evidence attests that this important hormone also regulates several cellular pathways involved in cancer development and progression. Calcitriol modulates several genes controlling gut physiology and calcium homeostasis and also maintains the integrity of epithelial barriers, regulates the absorption of phosphate and calcium, and modulates host defense against pathogens and inflammatory response by interplaying with several types of secretory and immune cells. Vitamin D deficiency is significantly related to increased risk of developing certain types of cancer. This deficiency can be prevented by vitamin D supplementation which is both economical and safe. This can lower the risk of developing cancer and also improve the prognosis of patients with gastrointestinal malignancy, but epidemiological data remain inconsistent. Several retrospective observational studies have demonstrated the benefits of vitamin D supplementation, but a few randomized controlled trials have not seemingly supported the beneficial role of vitamin D supplementation in gastrointestinal cancers. Therefore, in this literature review, we aimed to examine the possible role of vitamin D in gastrointestinal malignancies, including gastric, esophageal, pancreatic, hepatic, and colorectal cancers.

Circulating concentrations of vitamin D in relation to pancreatic cancer risk in European populations

Evidence from in vivo, in vitro and ecological studies are suggestive of a protective effect of vitamin D against pancreatic cancer (PC). However, this has not been confirmed by analytical epidemiological studies. We aimed to examine the association between pre-diagnostic circulating vitamin D concentrations and PC incidence in European populations. We conducted a pooled nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Nord-Trøndelag Health Study's second survey (HUNT2) cohorts. In total, 738 primary incident PC cases (EPIC n = 626; HUNT2 n = 112; median follow-up = 6.9 years) were matched to 738 controls. Vitamin D [25(OH)D2 and 25(OH)D3 combined] concentrations were determined using isotope-dilution liquid chromatography-tandem mass spectrometry. Conditional logistic regression models with adjustments for body mass index and smoking habits were used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (95%CI). Compared with a reference category of >50 to 75 nmol/L vitamin D, the IRRs (95% CIs) were 0.71 (0.42-1.20); 0.94 (0.72-1.22); 1.12 (0.82-1.53) and 1.26 (0.79-2.01) for clinically pre-defined categories of ≤25; >25 to 50; >75 to 100; and >100 nmol/L vitamin D, respectively (p for trend = 0.09). Corresponding analyses by quintiles of season-standardized vitamin D concentrations also did not reveal associations with PC risk (p for trend = 0.23). Although these findings among participants from the largest combination of European cohort studies to date show increasing effect estimates of PC risk with increasing pre-diagnostic concentrations of vitamin D, they are not statistically significant.

Physiologic and pathophysiologic roles of extra renal CYP27b1: Case report and review

Although the kidney was initially thought to be the sole organ responsible for the production of 1,25(OH)₂D via the enzyme CYP27b1, it is now appreciated that the expression of CYP27b1 in tissues other than the kidney is wide spread. However, the kidney is the major source for circulating 1,25(OH)₂D. Only in certain granulomatous diseases such as sarcoidosis does the extra renal tissue produce sufficient 1,25(OH)₂D to contribute to the circulating levels, generally associated with hypercalcemia, as illustrated by the case report preceding the review. Therefore the expression of CYP27b1 outside the kidney under normal circumstances begs the question why, and in particular whether the extra renal production of 1,25(OH)₂D has physiologic importance. In this chapter this question will be discussed. First we discuss the sites for extra renal 1,25(OH)₂D production. This is followed by a discussion of the regulation of CYP27b1 expression and activity in extra renal tissues, pointing out that such regulation is tissue specific and different from that of CYP27b1 in the kidney. Finally the physiologic significance of extra renal 1,25(OH)₂D₃ production is examined, with special focus on the role of CYP27b1 in regulation of cellular proliferation and differentiation, hormone secretion, and immune function. At this point the data do not clearly demonstrate an essential role for CYP27b1 expression in any tissue outside the kidney, but several examples pointing in this direction are provided. With the availability of the mouse enabling tissue specific deletion of CYP27b1, the role of extra renal CYP27b1 expression in normal and pathologic states can now be addressed definitively.

Plasma 25-hydroxyvitamin D levels, vitamin D intake, and pancreatic cancer risk or mortality: a meta-analysis

BACKGROUND

The associations between vitamin D status, including plasma 25-hydroxyvitamin D [25(OH)D] levels and vitamin D intake, and pancreatic cancer risk and mortality are inconsistent. The aims of this study are to evaluate the antitumor and therapeutic effects of vitamin D status for pancreatic cancer patients.

METHODS

A literature search for relevant studies was conducted using PubMed and Embase databases. Risk ratio (RR), hazard ratio (HR), and 95% confidence interval (CI) were used as the effect measures. All statistical analyses were performed using Stata software 12.0.

RESULTS

Our results indicated that high plasma 25(OH)D levels were inversely associated with pancreatic cancer mortality without significant heterogeneity (HR=0.81, 95% CI=0.68-0.96). However, high plasma 25(OH)D levels could not reduce pancreatic cancer risk (RR=1.02, 95% CI=0.66-1.57). Moreover, vitamin D intake was also not associated with pancreatic cancer risk (RR=1.11, 95% CI=0.67-1.86).

CONCLUSIONS

Our results indicate that high plasma 25(OH)D levels were significantly associated with improved survival in pancreatic cancer patients. However, there were no significant associations between vitamin D intake or plasma 25(OH)D levels and pancreatic cancer risk.

The role of vitamin D in hepatic metastases from colorectal cancer

Colorectal cancer (CRC) represents a significant health burden worldwide, comprising approximately 10% of annual cancer cases globally. Hepatic metastases are the most common site of CRC metastasis, and are the leading cause of death in CRC patients. There is strong epidemiologic evidence for an inverse association between vitamin D status and risk of CRC; however, the role of vitamin D in the natural history of liver metastases has not yet been investigated. Several researchers have proposed hallmarks of metastases; crucially, metastases can be blocked by interrupting just one rate-limiting step. Vitamin D status has been implicated in each proposed hallmark of metastasis. The aim of this review is to examine the potential role for vitamin D in reducing the development of hepatic metastases from CRC and outline the candidate mechanisms by which vitamin D may mediate these effects. The results of ongoing randomised intervention trials are eagerly awaited to determine whether addressing vitamin D insufficiency in CRC patients could reduce the occurrence of liver metastases, and the consequent morbidity and mortality.

Murine Pancreatic Acinar Cell Carcinoma Growth Kinetics Are Independent of Dietary Vitamin D Deficiency or Supplementation

Vitamin D has been proposed as a therapeutic strategy in pancreatic cancer, yet evidence for an effect of dietary vitamin D on pancreatic cancer is ambiguous, with conflicting data from human epidemiological and intervention studies. Here, we tested the role of dietary vitamin D in the in vivo context of the well-characterized Ela1-TAg transgenic mouse model of pancreatic acinar cell carcinoma. Through longitudinal magnetic resonance imaging of mice under conditions of either dietary vitamin D deficiency (<5 IU/kg vitamin D) or excess (76,500 IU/kg vitamin D), compared to control diet (1,500 IU/kg vitamin D), we measured the effect of variation of dietary vitamin D on tumor kinetics. No measurable impact of dietary vitamin D was found on pancreatic acinar cell carcinoma development, growth or mortality, casting further doubt on the already equivocal data supporting potential therapeutic use in humans. The lack of any detectable effect of vitamin D, within the physiological range of dietary deficiency or supplementation, in this model further erodes confidence in vitamin D as an effective antitumor therapeutic in pancreatic acinar cell carcinoma.

Vitamin D deficiency causes insulin resistance by provoking oxidative stress in hepatocytes

Vitamin D deficiency could cause insulin resistance. However, the underlying mechanisms are unclear. The 1α-Hydroxylase [“1α(OH)ase”] is a key enzyme for activate vitamin D3 synthesis. Here, we show that 1α(OH)ase stable knockdown by targeted shRNA led to vitamin D3 depletion in L02 hepatocytes. 1α(OH)ase silence also inhibited insulin-induced downstream signaling (IRS-1, ERK and AKT) transduction and glucose transporter 4 expression. Further, 1α(OH)ase shRNA in L02 hepatocytes led to significant reactive oxygen species production, p53-p21 activation and DNA damages. Such effects were almost completely reversed with co-treatment of n-acetylcysteine, which is an established anti-oxidant. Remarkably, insulin-induced downstream signaling transduction and glucose transporter 4 expression were recovered with n-acetylcysteine co-treatment in 1α(OH)ase-silenced L02 hepatocytes. Together, our results suggest that vitamin D deficiency-induced insulin resistance is possibly caused by oxidative stress in hepatocytes.

Insulin resistance in vitamin D-deficient mice is alleviated by n-acetylcysteine

Vitamin D deficiency will lead to insulin resistance. In the current study, vitamin D3 1α-Hydroxylase [“1α(OH)ase”] knockout mice were generated to mimic vitamin D deficiency in vivo. As compared to the wild-type mice, the liver tissues of the knockout mice showed impaired insulin signaling, decreased glucose transporter 4 expression and increased reactive oxygen species production. Meanwhile, p53-p21 activation, apoptosis intensity and pro-inflammatory cytokines (IL-6, IL-1 and MIP-1α) level were significantly increased in the knockout mice livers. Significantly, such effects in the knockout mice were largely attenuated by supplement with anti-oxidant n-acetylcysteine (NAC). Remarkably, insulin resistance and metabolic abnormalities in the knockout mice were largely alleviated after treatment of NAC. Therefore, inhibition of oxidative stress by NAC alleviated insulin resistance in vitamin D-deficient mice. Oxidative stress could be the primary cause of insulin resistance by vitamin D deficiency.

Vitamin D Impacts the Expression of Runx2 Target Genes and Modulates Inflammation, Oxidative Stress and Membrane Vesicle Biogenesis Gene Networks in 143B Osteosarcoma Cells

Osteosarcoma (OS) is an aggressive malignancy of bone affecting children, adolescents and young adults. Understanding vitamin D metabolism and vitamin D regulated genes in OS is an important aspect of vitamin D/cancer paradigm, and in evaluating vitamin D as adjuvant therapy for human OS. Vitamin D treatment of 143B OS cells induced significant and novel changes in the expression of genes that regulate: (a) inflammation and immunity; (b) formation of reactive oxygen species, metabolism of cyclic nucleotides, sterols, vitamins and mineral (calcium), quantity of gap junctions and skeletogenesis; (c) bone mineral density; and (d) cell viability of skeletal cells, aggregation of bone cancer cells and exocytosis of secretory vesicles. Ingenuity pathway analysis revealed significant reduction in Runx2 target genes such as fibroblast growth factor -1, -12 (FGF1 and FGF12), bone morphogenetic factor-1 (BMP1), SWI/SNF related, matrix associated actin dependent regulator of chromatin subfamily a, member 4 (SMARCA4), Matrix extracellular phosphoglycoprotein (MEPE), Integrin, β4 (ITGBP4), Matrix Metalloproteinase -1, -28 (MMP1 and MMP28), and signal transducer and activator of transcription-4 (STAT4) in vitamin D treated 143B OS cells. These genes interact with the inflammation, oxidative stress and membrane vesicle biogenesis gene networks. Vitamin D not only inhibited the expression of Runx2 target genes MMP1, MMP28 and kallikrein related peptidase-7 (KLK7), but also migration and invasion of 143B OS cells. Vitamin D regulated Runx2 target genes or their products represent potential therapeutic targets and laboratory biomarkers for applications in translational oncology.

Diet-derived 25-hydroxyvitamin D3 activates vitamin D receptor target gene expression and suppresses EGFR mutant non-small cell lung cancer growth in vitro and in vivo

Epidemiologic studies implicate vitamin D status as a factor that influences growth of EGFR mutant lung cancers. However, laboratory based evidence of the biological effect of vitamin D in this disease is lacking. To fill this knowledge gap, we determined vitamin D receptor (VDR) expression in human lung tumors using a tissue microarray constructed of lung cancer cases from never-smokers (where EGFR gene mutations are prevalent). Nuclear VDR was detected in 19/19 EGFR mutant tumors. Expression tended to be higher in tumors with EGFR exon 19 deletions than those with EGFR L858R mutations. To study anti-proliferative activity and signaling, EGFR mutant lung cancer cells were treated with the circulating metabolite of vitamin D, 25-hydroxyvitamin D3 (25D3). 25D3 inhibited clonogenic growth in a dose-dependent manner. CYP27B1 encodes the 1α-hydroxylase (1αOHase) that converts 25D3 to the active metabolite, 1,25-dihydroxyvitamin D3 (1,25D3). Studies employing VDR siRNA, CYP27B1 zinc finger nucleases, and pharmacologic inhibitors of the vitamin D pathway indicate that 25D3 regulates gene expression in a VDR-dependent manner but does not strictly require 1αOHase-mediated conversion of 25D3 to 1,25D3. To determine the effects of modulating serum 25D3 levels on growth of EGFR mutant lung tumor xenografts, mice were fed diets containing 100 or 10,000 IU vitamin D3/kg. High dietary vitamin D3 intake resulted in elevated serum 25D3 and significant inhibition of tumor growth. No toxic effects of supplementation were observed. These results identify EGFR mutant lung cancer as a vitamin D-responsive disease and diet-derived 25D3 as a direct VDR agonist and therapeutic agent.

25(OH)D Is Effective to Repress Human Cholangiocarcinoma Cell Growth through the Conversion of 25(OH)D to 1α,25(OH)₂D₃

Cholangiocarcinoma (CCA) is a devastating disease without effective treatments. 1α,25(OH)₂D₃, the active form of Vitamin D, has emerged as a new anti-cancer regimen. However, the side effect of hypercalcemia impedes its systemic administration. 25(OH)D is biologically inert and needs hydroxylation by CYP27B1 to form 1α,25(OH)₂D₃, which is originally believed to only take place in kidneys. Recently, the extra-renal expression of CYP27B1 has been identified and in vitro conversion of 25(OH)D to 1α,25(OH)₂D₃ has been found in some cancer cells with CYP27B1 expression. In this study, CYP27B1 expression was demonstrated in CCA cells and human CCA specimens. 25(OH)D effectively represses SNU308 cells growth, which was strengthened or attenuated as CYP27B1 overexpression or knockdown. Lipocalcin-2 (LCN2) was also found to be repressed by 25(OH)D. After treatment with 800 ng/mL 25(OH)D, the intracellular 1α,25(OH)₂D₃ concentration was higher in SNU308 cells with CYP27B1 overexpression than wild type SNU308 cells. In a xenograft animal experiment, 25(OH)D, at a dose of 6 μg/kg or 20 μg/kg, significantly inhibited SNU308 cells’ growth without inducing obvious side effects. Collectively, our results indicated that SNU308 cells were able to convert 25(OH)D to 1α,25(OH)₂D₃ and 25(OH)D CYP27B1 gene therapy could be deemed as a promising therapeutic direction for CCA.

Prediagnostic Plasma 25-Hydroxyvitamin D and Pancreatic Cancer Survival

PURPOSE

Although vitamin D inhibits pancreatic cancer proliferation in laboratory models, the association of plasma 25-hydroxyvitamin D [25(OH)D] with patient survival is largely unexplored.

PATIENTS AND METHODS

We analyzed survival among 493 patients from five prospective US cohorts who were diagnosed with pancreatic cancer from 1984 to 2008. We estimated hazard ratios (HRs) for death by plasma level of 25(OH)D (insufficient, < 20 ng/mL; relative insufficiency, 20 to < 30 ng/mL; sufficient ≥ 30 ng/mL) by using Cox proportional hazards regression models adjusted for age, cohort, race and ethnicity, smoking, diagnosis year, stage, and blood collection month. We also evaluated 30 tagging single-nucleotide polymorphisms in the vitamin D receptor gene, requiring P < .002 (0.05 divided by 30 genotyped variants) for statistical significance.

RESULTS

Mean prediagnostic plasma level of 25(OH)D was 24.6 ng/mL, and 165 patients (33%) were vitamin D insufficient. Compared with patients with insufficient levels, multivariable-adjusted HRs for death were 0.79 (95% CI, 0.48 to 1.29) for patients with relative insufficiency and 0.66 (95% CI, 0.49 to 0.90) for patients with sufficient levels (P trend = .01). These results were unchanged after further adjustment for body mass index and history of diabetes (P trend = .02). The association was strongest among patients with blood collected within 5 years of diagnosis, with an HR of 0.58 (95% CI, 0.35 to 0.98) comparing patients with sufficient to patients with insufficient 25(OH)D levels. No single-nucleotide polymorphism at the vitamin D receptor gene met our corrected significance threshold of P < .002; rs7299460 was most strongly associated with survival (HR per minor allele, 0.80; 95% CI, 0.68 to 0.95; P = .01).

CONCLUSION

We observed longer overall survival in patients with pancreatic cancer who had sufficient prediagnostic plasma levels of 25(OH)D.

Tumoral Vitamin D Synthesis by CYP27B1 1-α-Hydroxylase Delays Mammary Tumor Progression in the PyMT-MMTV Mouse Model and Its Action Involves NF-κB Modulation

Biologically active vitamin D (1,25-dihydroxycholecalciferol or 1,25(OH)2D) is synthetized from inactive prohormone 25-hydroxycholecalciferol (25(OH)D) by the enzyme CYP27B1 1-α-hydroxylase in kidney and several extrarenal tissues including breast. Although the development of breast cancer has been linked to inadequate vitamin D status, the importance of bioactive vitamin D production within tumors themselves is not fully understood. To investigate the role of tumoral vitamin D production in mammary epithelial cell progression to breast cancer, we conducted a Cre-loxP-mediated Cyp27b1 gene ablation in the mammary epithelium of the polyoma middle T antigen-mouse mammary tumor virus (PyMT-MMTV) mouse breast cancer model. Targeted ablation of Cyp27b1 was accompanied by significant acceleration in initiation of spontaneous mammary tumorigenesis. In vivo, cell proliferation, angiogenesis, cell cycle progression, and survival markers were up-regulated in tumors by Cyp27b1 ablation, and apoptosis was decreased. AK thymoma (AKT) phosphorylation and expression of several components of nuclear factor κB (NF-κB), integrin, and signal transducer and activator of transcription 3 (STAT3) signaling pathways were increased in Cyp27b1-ablated tumors compared with nonablated controls. In vitro, 1,25(OH)2D treatment induced a strong antiproliferative action on tumor cells from both ablated and nonablated mice, accompanied by rapid disappearance of NF-κB p65 from the nucleus and segregation in the cytoplasm. In contrast, treatment with the metabolic precursor 25(OH)D was only effective against cells from nonablated mice. 25(OH)D did not inhibit growth of Cyp27b1-ablated cells, and their nuclear NF-κB p65 remained abundant. Our findings demonstrate that in-tumor CYP27B1 1-α-hydroxylase activity plays a crucial role in controlling early oncogene-mediated mammary carcinogenesis events, at least in part by modulating tumoral cell NF-κB p65 nuclear translocation.

Comparative effect of 25(OH)D3 and 1,25(OH)2D3 on Th17 cell differentiation

Vitamin D is a secosteroid hormone that plays an important regulatory role in calcium homeostasis and bone metabolism. Immune cells can both produce and respond to 1,25(OH)2D3. CD4+ T cells from vitamin D receptor (VDR) KO mice produce higher levels of IFN-γ and IL-17 than their wild type counterparts, and play a crucial role in the pathogenesis of autoimmune diseases (AID). We are particularly interested in studying the effect of vitamin D on pathogenic Th17 cells in humans. We investigated the in vitro effect of 1,25(OH)2D3 and 25(OH)D3 on the differentiation and cytokine production of primary CD4+ T cells from normal donors, and cultured in Th17 polarizing conditions. Both forms of vitamin D reduced the expression of pathogenic Th17 markers and their secretion of pro-inflammatory cytokines (IL-17A, IFN-γ). Furthermore, both vitamin D forms induced an expansion of CD25hi cells and upregulated their expression of CTLA-4 and Foxp3 regulatory markers.

Retrospective analysis of the influence of 25-hydroxyvitamin D on disease progression and survival in pancreatic cancer

Background

Vitamin D deficiency is implicated in neoplastic processes in multiple organs, including the pancreas. While animal and human data have established a relationship between serum vitamin D (25(OH)D) and the development of pancreatic cancer, few studies have examined the effects of 25(OH)D on time to progression (TTP) and overall survival (OS) in this patient population. We hypothesize that lower baseline serum concentrations (BSC) of 25(OH)D will be associated with decreased TTP and OS.

Methods

This retrospective analysis of 1222 patients with pancreatic cancer aims to identify potential relationships between 25(OH)D and both TTP and OS, while controlling for the effects of ethnicity and body mass index (BMI). Baseline 25(OH)D was divided into quartiles defined as deficient (<20 ng/mL), insufficient (20–39 ng/mL), sufficient (40–59 ng/mL), and optimal (≥60 ng/ml). Statistical significance was declared if the two-sided p-value was ≤ 0.05.

Results

For the 627 subjects included for analysis, the median 25(OH)D was 27 ng/mL (range 4 to 114), 30.0 % were 25(OH)D deficient (<20 ng/mL), and 47.2 % were insufficient (20–39 ng/mL). Ethnicity (p < 0.0001) and BMI (p = 0.05) were significantly associated with (BSC)of 25(OH)D, while TTP (p = 0.39) and OS (p = 0.37) were not associated.

Conclusion

Suboptimal vitamin D levels (<60 ng/mL) occurred in 96 % of patients analyzed. Both ethnicity and BMI were statistically significantly associated with vitamin D deficiency and insufficiency. Similar to results previously reported in the literature, this analysis did not identify a significant association between BSC of 25(OH)D and OS or TTP in patients with pancreatic cancer.

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.

PLGA nanoparticles as a platform for vitamin D-based cancer therapy

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles were studied as drug delivery vehicles for calcitriol, the active form of vitamin D3. In vitro effects of calcitriol encapsulated in PLGA nanoparticles were evaluated with respect to free calcitriol on human pancreatic cell lines, S2-013 and hTERT-HPNE, and the lung cancer cell line A549. Encapsulated calcitriol retained its biological activity, reducing the cell growth. Cytotoxicity assays demonstrated that encapsulation of calcitriol enhanced its inhibitory effect on cell growth at a concentration of 2.4 μM for the S2-013 cells (91%) and for A549 cells (70%) comparared to the free calcitriol results. At this concentration the inhibitory effect on nontumor cells (hTERT-HPNE) decreased to 65%. This study highlights the ability of PLGA nanoparticles to deliver vitamin D3 into cancer cells, with major effects regarding cancer cell cycle arrest and major changes in the cell morphological features.

Vitamin D-binding protein and pancreatic cancer: a nested case-control study

BACKGROUND

Vitamin D-binding protein (DBP) is the primary carrier of 25-hydroxyvitamin D [25(OH)D] in the circulation. One prospective study in male smokers found a protective association between DBP and pancreatic cancer, particularly among men with higher 25(OH)D concentrations.

OBJECTIVE

The objective was to examine the association between DBP and pancreatic cancer risk in an American population.

DESIGN

We conducted a nested case-control study in the Prostate, Lung, Colorectal, and Ovarian Cancer screening trial cohort of men and women aged 55-74 y at baseline. Between 1993 and 2010, 295 incident pancreatic adenocarcinoma cases were reported (follow-up to 15.1 y). Two controls (n = 590) were matched to each case by age, race, sex, and month of blood draw. We calculated smoking- and diabetes-adjusted ORs and 95% CIs with the use of conditional logistic regression.

RESULTS

DBP concentration was not significantly associated with pancreatic cancer overall [highest (≥7149.4 nmol/L) vs. lowest (<3670.4 nmol/L) quintile; OR: 1.75; 95% CI: 0.91, 3.37; P-trend = 0.25]. For serum 25(OH)D compared with the referent (50 to <75 nmol/L), individuals in the highest group had a significantly higher risk (≥100 nmol/L; OR: 3.23; 95% CI: 1.24, 8.44), whereas those in the lowest group had no significant association (<25 nmol/L; OR: 2.50; 95% CI: 0.92, 6.81). Further adjustment for DBP did not alter this association.

CONCLUSION

Our results do not support the hypothesis that serum DBP or 25(OH)D plays a protective role in pancreatic cancer. This trial was registered at clinicaltrials.gov as NCT00339495.

Vitamin D and GI cancers: shedding some light on dark diseases

VITAMIN D SYNTHESIS AND SIGNALING AFFECTS NUMEROUS CELLULAR PROCESSES INCLUDING: proliferation, differentiation and apoptosis. It is now commonly recognized that low levels of vitamin D are associated with a greater risk of tumorigenesis. Cancers of the gastrointestinal tract are most often difficult to diagnose and treat as patients typically present with progressed disease. Basic research, clinical trials and population studies have supported the concept that treatment with Vitamin D may be a therapeutic option when treating GI cancers, however treatments must be individualized and monitored closely as the side effects from Vitamin D treatment can be increasingly harmful. This review will highlight the most recent findings regarding Vitamin D signaling and GI cancers.

25-Hydroxyvitamin D levels and survival in advanced pancreatic cancer: findings from CALGB 80303 (Alliance)

BACKGROUND

Data from animal and cell-line models suggest that vitamin D metabolism plays an important role in pancreatic tumor behavior. Although vitamin D deficiency has been implicated in numerous cancers, the vitamin D status of patients with advanced pancreatic cancer and the effect of baseline vitamin D levels on survival are unknown.

METHODS

Participants in this correlative study (CALGB 151006) were enrolled in CALGB 80303, which was a randomized trial of patients with advanced pancreatic cancer that demonstrated no difference in overall survival (OS) among patients treated with gemcitabine plus placebo vs gemcitabine plus bevacizumab. We measured baseline serum 25-hydroxyvitamin D (25[OH]D) levels and examined associations between baseline 25(OH)D levels and progression-free survival and OS using the Cox rank score test. All statistical tests were two-sided.

RESULTS

Of 256 patients with available serum, the median 25(OH)D level was 21.7ng/mL (range 4 to 77). 44.5% of patients were vitamin D deficient (25[OH]D <20ng/mL), and 32.4% were insufficient (25[OH]D ≥20 and <30ng/mL). 25(OH)D levels were lower in black patients compared with white patients, and patients of other/undisclosed race (10.7 vs 22.4 vs 20.9ng/mL, P < .001). Baseline 25(OH)D levels were not associated with PFS (HR = 1.00, 95% CI = 0.99 to 1.01, P = .60) or OS (HR = 1.00, 95% CI = 0.99 to 1.01, P = .95).

CONCLUSION

Vitamin D deficiency was highly prevalent among patients with a new diagnosis of advanced pancreatic cancer. Black patients had statistically significantly lower 25(OH)D levels than white patients. In this cohort of patients with advanced pancreatic cancer receiving gemcitabine-based chemotherapy, baseline 25(OH)D levels were not associated with PFS or OS.

Genetic variants in vitamin d pathway genes and risk of pancreas cancer; results from a population-based case-control study in ontario, Canada

Recent studies of 25-hydroxyvitamin D (25(OH)D) levels and pancreas cancer have suggested a potential role of the vitamin D pathway in the etiology of this fatal disease. Variants in vitamin-D related genes are known to affect 25(OH)D levels and function and it is unknown if these variants may influence pancreatic cancer risk. The association between 87 single nucleotide polymorphisms (SNPs) in 11 genes was evaluated within the Ontario Pancreas Cancer Study, a population-based case-control study. Pancreatic cancer cases with pathology confirmed adenocarcinoma were identified from the Ontario Cancer Registry (n = 628) and controls were identified through random digit dialing (n = 1193). Age and sex adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated by multivariate logistic regression. SNPs in the CYP24A1, CYP2R1, calcium sensing receptor (CASR), vitamin D binding protein (GC), retinoid X receptor-alpha (RXRA) and megalin (LRP2) genes were significantly associated with pancreas cancer risk. For example, pancreas cancer risk was inversely associated with CYP2R1 rs10741657 (AA versus GG, OR = 0.70; 95%CI: 0.51-0.95) and positively with CYP24A1 rs6127119 (TT versus CC. OR = 1.94; 95%CI: 1.28-2.94). None of the associations were statistically significant after adjustment for multiple comparisons. Vitamin D pathway gene variants may be associated with pancreas cancer risk and future studies are needed to understand the possible role of vitamin D in tumorigenesis and may have implications for cancer-prevention strategies.

Effects of vitamin D on immune disorders with special regard to asthma, COPD and autoimmune diseases: a short review

This paper reviews the recent data on the role of vitamin D (VD) in the genesis of various immunological disorders. It inhibits immune reactions in general, but it enhances the transcription of 'endogenous antibiotics' such as cathelicidin and defensins. VD inhibits the genesis of both Th1- and Th2-cell mediated diseases. The pleiotropic character VD-induced effects are due to the altered transcription of hundreds of genes. VD supplementation in most related studies reduced the prevalence of asthma. Th1-dependent autoimmune diseases (e.g., multiple sclerosis, Type 1 diabetes, Crohn's disease, rheumatoid arthritis and so on) are also inhibited by VD due to inhibition of antigen presentation, reduced polarization of Th0 cells to Th1 cells and reduced production of cytokines from the latter cells. VD seems to also be a useful adjunct in the prevention of allograft rejection. Last but not least, VD supplementation may be useful in the prevention or adjunct treatment of chronic obstructive pulmonary disease.

Vitamin D status and outcomes after renal transplantation

Kidney transplant recipients usually have low vitamin D levels, especially in the early posttransplantation period, but the association between vitamin D status with renal outcomes is not well described in this population. Here, we studied a prospective cohort of 634 kidney recipients who underwent transplantation at a single institution between January 2005 and June 2010. In this cohort, low 25-hydroxyvitamin D concentrations 3 months after transplantation did not predict early death or graft loss but were independently associated with lower measured GFR at 12 months (P=0.001) and higher risk for interstitial fibrosis and tubular atrophy (P=0.01). In contrast, levels of calcium, phosphorus, calcitriol, parathyroid hormone, or fibroblast growth factor-23 were not consistently associated with any of the studied outcomes. In conclusion, low 25-hydroxyvitamin D concentration measured 3 months after transplantation is an independent risk factor for interstitial fibrosis progression and is associated with a lower GFR 1 year after transplantation.

Resveratrol stimulates cortisol biosynthesis by activating SIRT-dependent deacetylation of P450scc

In the human adrenal cortex, cortisol is synthesized from cholesterol by members of the cytochrome P450 superfamily and hydroxysteroid dehydrogenases. Both the first and last steps of cortisol biosynthesis occur in mitochondria. Based on our previous findings that activation of ACTH signaling changes the ratio of nicotinamide adenine dinucleotide (NAD) phosphate to reduced NAD phosphate in adrenocortical cells, we hypothesized that pyridine nucleotide metabolism may regulate the activity of the mitochondrial NAD(+)-dependent sirtuin (SIRT) deacetylases. We show that resveratrol increases the protein expression and half-life of P450 side chain cleavage enzyme (P450scc). The effects of resveratrol on P450scc protein levels and acetylation status are dependent on SIRT3 and SIRT5 expression. Stable overexpression of SIRT3 abrogates the cellular content of acetylated P450scc, concomitant with an increase in P450scc protein expression and cortisol secretion. Mutation of K148 and K149 to alanine stabilizes the expression of P450scc and results in a 1.5-fold increase in pregnenolone biosynthesis. Finally, resveratrol also increases the protein expression of P450 11β, another mitochondrial enzyme required for cortisol biosynthesis. Collectively, this study identifies a role for NAD(+)-dependent SIRT deacetylase activity in regulating the expression of mitochondrial steroidogenic P450.

Vitamin D and cancer

Vitamin D system is a complex pathway that includes precursors, active metabolites, enzymes, and receptors. This complex system actives several molecular pathways and mediates a multitude of functions. In addition to the classical role in calcium and bone homeostasis, vitamin D plays "non-calcemic" effects in host defense, inflammation, immunity, and cancer processes as recognized in vitro and in vivo studies. The aim of this review is to highlight the relationship between vitamin D and cancer, summarizing several mechanisms proposed to explain the potential protective effect of vitamin D against the development and progression of cancer. Vitamin D acts like a transcription factor that influences central mechanisms of tumorigenesis: growth, cell differentiation, and apoptosis. In addition to cellular and molecular studies, epidemiological surveys have shown that sunlight exposure and consequent increased circulating levels of vitamin D are associated with reduced reduced occurrence and a reduced mortality in different histological types of cancer. Another recent field of interest concerns polymorphisms of vitamin D receptor (VDR); in this context, preliminary data suggest that VDR polymorphisms more frequently associated with tumorigenesis are Fok1, Bsm1, Taq1, Apa1, EcoRV, Cdx2; although further studies are needed to clarify their role in the cancer. In this review, the relationship between vitamin D and cancer is discussed.

Is dietary fat, vitamin D, or folate associated with pancreatic cancer?

Although potentially modifiable risk factors for pancreatic cancer include smoking, obesity, and diabetes, less is known about the extent to which diet affects cancer risk. Recent studies have demonstrated some consistency for dietary fat being associated with elevated pancreatic cancer risk, particularly from animal sources. However, less is known about which fatty acids pose the greatest risk. Vitamin D, due to its endogenous production following UV-B exposure, is a unique risk factor in that researchers have created several methods to assess its exposure in humans. Studies that measured vitamin D exposure differently have shown inconsistent results. Dietary studies suggest protective associations, whereas studies of circulating 25-hydroxyvitamin D status show null or positive associations with low or very high concentrations, respectively. Several, but not all epidemiologic studies provide evidence of an inverse relationship between total and/or dietary folate and risk of pancreatic cancer. Protective associations for circulating folate are more often observed among populations with inadequate status. This article reviews the current epidemiological and experimental evidence investigating the relationship of dietary fat, vitamin D, and folate with pancreatic cancer. Additionally the mechanisms by which these risk factors may contribute to cancer, the methodological challenges involved with assessing risk, and other obstacles encountered when ascertaining the magnitude and direction of these three exposures are discussed.

Vitamin D metabolism and activity in the parathyroid gland

Parathormone (PTH) and vitamin D are two critical hormonal regulators of calcium homeostasis. An important cross-talk exists between the PTH and vitamin D hormonal systems. PTH enhances vitamin D hydroxylation on carbon 1 in kidney cells thereby allowing the systemic release of 1-25-dihydroxy-vitamin D, which represents the fully active hormone. Conversely, parathyroid gland represents a direct target for vitamin D. Parathyroid cells express the vitamin D receptor and the 1-α-hydroxylase enzyme, which allows the local formation of 1-25-dihydroxy-vitamin D. Because of its potential implication in several diseases, including osteoporosis or chronic kidney disease, the interplay between PTH and vitamin D has received considerable attention these last two decades. The aim of this review is to summarize our current understanding of the molecular basis of vitamin D action and metabolism in parathyroid cells. The potential clinical implications of the recent advances made in this field will also be discussed.

Plasma 25-hydroxyvitamin D and risk of pancreatic cancer

BACKGROUND

Laboratory studies suggest that vitamin D may inhibit pancreatic cancer cell growth. However, epidemiologic studies of vitamin D and pancreatic cancer risk have been conflicting.

METHODS

To determine whether prediagnostic levels of plasma 25-hydroxyvitamin D (25[OH]D; IDS Inc.; enzyme immunoassay) were associated with risk of pancreatic cancer, we conducted a pooled analysis of nested case-control studies with 451 cases and 1,167 controls from five cohorts through 2008. Median follow-up among controls was 14.1 years in Health Professionals Follow-Up Study (HPFS), 18.3 years in Nurses' Health Study (NHS), 25.3 years in Physicians' Health Study (PHS), 12.2 years in Women's Health Initiative-Observational Study (WHI), and 14.4 years in Women's Health Study (WHS). Logistic regression was used to compare the odds of pancreatic cancer by plasma level of 25(OH)D.

RESULTS

Mean plasma 25(OH)D was lower in cases versus controls (61.3 vs. 64.5 nmol/L, P = 0.005). In logistic regression models, plasma 25(OH)D was inversely associated with odds of pancreatic cancer. Participants in quintiles two through five had multivariable-adjusted ORs (95% confidence intervals) of 0.79 (0.56-1.10), 0.75 (0.53-1.06), 0.68 (0.48-0.97), and 0.67 (0.46-0.97; P(trend) = 0.03), respectively, compared with the bottom quintile. Compared with those with insufficient levels [25[OH]D, <50 nmol/L], ORs were 0.75 (0.58-0.98) for subjects with relative insufficiency [25[OH]D, 50 to <75 nmol/L] and 0.71 (0.52-0.97) for those with sufficient levels [25[OH]D, ≥ 75 nmol/L]. No increased risk was noted in subjects with 25(OH)D ≥100 nmol/L, as suggested in a prior study. In subgroup analyses, ORs for the top versus bottom quartile of 25(OH)D were 0.72 (0.48-1.08) for women, 0.73 (0.40-1.31) for men, and 0.73 (0.51-1.03) for Whites.

CONCLUSIONS

Among participants in five large prospective cohorts, higher plasma levels of 25(OH)D were associated with a lower risk for pancreatic cancer.

IMPACT

Low circulating 25(OH)D may predispose individuals to the development of pancreatic cancer.

Extra-skeletal effects of vitamin D deficiency in chronic kidney disease

Cardiovascular diseases (CVD) and infectious diseases represent the two most important causes of death in patients with chronic kidney disease (CKD). The traditional risk factors of CVD do not appear to account sufficiently for the increased risk of CVD in patients with CKD, and vitamin D deficiency appears to be an important non-traditional, and potentially modifiable, CVD risk factor in this patient population. 25-Hydroxyvitamin D (25(OH)D) is converted to its biologically active form, 1,25-dihydroxyvitamin D (1,25(OH)(2)D), by the enzyme 1α-hydroxylase in the kidneys. The recent discovery that many extrarenal tissues also possess both the 1α-hydroxylase enzyme and the vitamin D receptors has provided new insights into the important physiologic autocrine and paracrine roles of vitamin D in various tissues and organs that are mainly dependent on the availability of 25(OH)D from the circulating plasma. Accordingly, the present review focuses on the rapidly expanding body of clinical and experimental evidence that supports a strong association between 25(OH)D deficiency/insufficiency and the risk of adverse CVD outcomes and infectious diseases as well as on the non-calcemic autocrine and paracrine actions of vitamin D both in the general population and in patients with CKD.

Melanoma and vitamin D

Vitamin D is a fat-soluble steroid hormone, which is essential to health and for which epidemiological studies suggest a role in autoimmune disease, infections, cardiovascular disease and cancer. It is ingested in foods such as oily fish and supplements, so that average levels vary between countries, but most individuals worldwide make most of their vitamin D as a result of the effects of sun exposure on the skin. Many studies in different populations around the world have in recent years shown that sub-optimal levels of vitamin D (<70 nmol/L) are common. A series of epidemiological studies have suggested that low vitamin D levels increase the risk of cancers, particularly of the breast and gastrointestinal tracts, so that there has been much interest in understanding the effects of vitamin D on cancer cells. Vitamin D binds to the vitamin D receptor (VDR) resulting in transcription of a number of genes playing a role in inhibition of MAPK signalling, induction of apoptosis and cell-cycle inhibition, and therefore vitamin D has anti-proliferative and pro-apoptotic effects in cells of many lineages. It also has suppressive effects on adaptive immunity and is reported to promote innate immunity. Here we review data on vitamin D and melanoma. There are in vitro data, which suggest that vitamin D has the same anti-proliferative effects on melanoma cells as have been demonstrated in other cells. We have reported data to suggest that vitamin D levels at diagnosis have a role in determining outcome for melanoma patients. There is a curious relationship between melanoma risk and sun exposure where sunburn is causal but occupational sun exposure is not (at least in temperate climes). Seeking to understand this, we discuss data, which suggest (but by no means prove) that vitamin D might also have a role in susceptibility to melanoma. In conclusion, much remains unknown about vitamin D in general and certainly about vitamin D and melanoma. However, the effects of avoidance of suboptimal vitamin D levels on cancer cell proliferation are likely to be beneficial to the melanoma patient. The possible results of high vitamin D levels on the immune system remain unclear however and a source of some concern, but the data support the view that serum levels in the range 70-100 nmol/L might be a reasonable target for melanoma patients as much as for other members of the population.

Nutrigenomics, vitamin D and cancer prevention

Although there is growing epidemiological, preclinical and clinical evidence suggesting that low vitamin D intake, exposure and/or status is associated with an increased risk of various types of cancer, the optimum amount needed remains controversial. Furthermore, there is evidence that a U- or J-shaped response curve exist between 25(OH)D and certain cancers. Increasing information about the impact of genetic variation, especially polymorphisms that influence absorption, transport, metabolism and associated molecular targets, should help clarify inconsistencies in the data regarding vitamin D's effect on cancer risk. Rather than focusing on the main effects of a few variants of these genes alone, future studies need to consider gene-nutrient or environmental interactions. Nutrigenomics should clarify who might benefit and be placed at risk because of vitamin D exposure.

Role of vitamin d in the prevention of pancreatic cancer

Pancreatic cancer is a malignancy of poor prognosis which is mostly diagnosed at advanced stages. Current treatment modalities are very limited creating great interest for novel preventive and therapeutic options. Vitamin D seems to have a protective effect against pancreatic cancer by participating in numerous proapoptotic, antiangiogenic, anti-inflammatory, prodifferentiating, and immunomodulating mechanisms. 25-hydroxyvitamin D [25(OH)D] serum concentrations are currently the best indicator of vitamin D status. There are three main sources of vitamin D: sun exposure, diet,and dietary supplements. Sun exposure has been associated with lower incidence of pancreatic cancer in ecological studies. Increased vitamin D levels seem to protect against pancreatic cancer, but caution is needed as excessive dietary intake may have opposite results. Future studies will verify the role of vitamin D in the prevention and therapy of pancreatic cancer and will lead to guidelines on adequate sun exposure and vitamin D dietary intake.

Vitamin d and pancreatic cancer-an update

The non-classical actions of vitamin D, namely anti-proliferation, pro-differentiation, immune function modulation, and anti-inflammation, have received great attention during the past decade, in particular, the potential of vitamin D analogs alone or in combination with other anticancer agents for the treatment of a variety of cancers. The association between vitamin D status and the higher incidence of many forms of cancer has suggested that vitamin D may play a role in the etiology of these types of cancer. Although it is still controversial whether this association exists for pancreatic cancer, biochemical evidence clearly indicates pancreatic cancer cells are responsive to the inhibitory effect of vitamin D and its analogs. In this review, we discuss briefly the origin and current therapy of pancreatic cancer, the history, source, metabolism and functions of vitamin D, the recent progress in the epidemiological studies of sunlight, and vitamin D status, and biochemical studies of vitamin D analogs in the prevention and treatment of pancreatic cancer.

DNA methylation-related vitamin D receptor insensitivity in breast cancer

Calcitriol (1α, 25(OH)(2)-Vitamin D3) binds to the vitamin D receptor (VDR) and regulates differentiation of the normal mammary gland, and may therefore be useful in breast cancer treatment or prevention. Many breast cancer cells are, however, resistant to Calcitriol. In this study, we investigated the resistance mechanism and the role of epigenetic silencing of VDR by promoter hypermethylation. Bisulfite sequencing of the VDR promoter region revealed methylated CpG islands at -700 base pairs (bp) upstream and near the transcription start site. VDR CpG islands were demethylated by 5'deoxy-azacytidine treatment, and this was accompanied by a parallel increase in VDR mRNA levels in breast cancer cell lines. Quantitative methylation-specific PCR analyses confirmed hypermethylation of these CpG islands in primary tumors, and its absence in normal breast tissue. VDR transcripts detected in breast cancers were predominantly 5'-truncated, while normal breast tissue expressed full-length transcripts. Consistent with this observation, genes containing the VDR-responsive element (VDRE), such as cytochrome p450 hydroxylases, p21 or C/EBP were underexpressed in breast cancers compared to normal breast samples. Expression of the active longer transcripts of VDR was restored with 5'deoxy-Azacytidine (AZA) treatment, with a concurrent increase in expression of VDRE-containing genes. Thus, promoter methylation-mediated silencing of expression of the functional variants of VDR may contribute to reduced expression of downstream effectors of the VDR pathway and subsequent Calcitriol insensitivity in breast cancer. These data suggest that pharmacological reversal of VDR methylation may re-establish breast cancer cell susceptibility to differentiation therapy using Calcitriol.

Circulating 25-hydroxyvitamin D and risk of pancreatic cancer: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers

Results from epidemiologic studies examining pancreatic cancer risk and vitamin D intake or 25-hydroxyvitamin D (25(OH)D) concentrations (the best indicator of vitamin D derived from diet and sun) have been inconsistent. Therefore, the authors conducted a pooled nested case-control study of participants from 8 cohorts within the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers (VDPP) (1974-2006) to evaluate whether prediagnostic circulating 25(OH)D concentrations were associated with the development of pancreatic cancer. In total, 952 incident pancreatic adenocarcinoma cases occurred among participants (median follow-up, 6.5 years). Controls (n = 1,333) were matched to each case by cohort, age, sex, race/ethnicity, date of blood draw, and follow-up time. Conditional logistic regression analysis was used to calculate smoking-, body mass index-, and diabetes-adjusted odds ratios and 95% confidence intervals for pancreatic cancer. Clinically relevant 25(OH)D cutpoints were compared with a referent category of 50-<75 nmol/L. No significant associations were observed for participants with lower 25(OH)D status. However, a high 25(OH)D concentration (> or =100 nmol/L) was associated with a statistically significant 2-fold increase in pancreatic cancer risk overall (odds ratio = 2.12, 95% confidence interval: 1.23, 3.64). Given this result, recommendations to increase vitamin D concentrations in healthy persons for the prevention of cancer should be carefully considered.

Predicted vitamin D status and pancreatic cancer risk in two prospective cohort studies

Background:

Studies evaluating vitamin D status in relation to pancreatic cancer risk have yielded inconsistent results.

Methods:

We prospectively followed 118 597 participants in the Nurses' Health Study and Health Professionals Follow-up Study from 1986 to 2006. We calculated a 25-hydroxyvitamin D (25(OH)D) score from known predictors of vitamin D status for each individual and then examined the predicted 25(OH)D levels in relation to pancreatic cancer risk. Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated using Cox proportional hazards models adjusted for age, sex, race, height, smoking, and diabetes. We then further adjusted for body mass index (BMI) and physical activity in a sensitivity analysis.

Results:

During 20 years of follow-up, we identified 575 incident pancreatic cancer cases. Higher 25(OH)D score was associated with a significant reduction in pancreatic cancer risk; compared with the lowest quintile, participants in the highest quintile of 25(OH)D score had an adjusted RR of 0.65 (95% CI=0.50–0.86; P_trend=0.001). Results were similar when we further adjusted for BMI and physical activity.

Conclusions:

Higher 25(OH)D score was associated with a lower risk of pancreatic cancer in these two prospective cohort studies.

Vitamin D: considerations in the continued development as an agent for cancer prevention and therapy

Considerable preclinical and epidemiologic data suggest that vitamin D may play a role in the pathogenesis, progression, and therapy for cancer. Numerous epidemiologic studies support the hypothesis that individuals with lower serum vitamin D levels have a higher risk of a number of cancers. Measures of vitamin D level in such studies include both surrogate estimates of vitamin D level (residence in more northern latitudes, history of activity, and sun exposure) as well as measured serum 25(OH) cholecalciferol levels. Perhaps, the most robust of these epidemiologic studies is that of Giovannucci et al, who developed and validated an estimate of serum 25(OH) cholecalciferol level and reported that among >40,000 individuals in the Health Professionals Study, an increase in 25(OH) cholecalciferol level of 62.5 ng/mL was associated with a reduction in the risk of head/neck, esophagus, pancreas cancers, and acute leukemia by >50%. Unfortunately, very limited data are available to indicate whether or not giving vitamin D supplements reduces the risk of cancer. Many preclinical studies indicate that exposing cancer cells, as well as vascular endothelial cells derived from tumors, to high concentrations of active metabolites of vitamin D halts progression through cell cycle, induces apoptosis and will slow or stop the growth of tumors in vivo. There are no data that one type of cancer is more or less susceptible to the effects of vitamin D. Vitamin D also potentiates the antitumor activity of a number of types of cytotoxic anticancer agents in in vivo preclinical models. Vitamin D analogues initiate signaling through a number of important pathways, but the pathway(s) essential to the antitumor activities of vitamin D are unclear. Clinical studies of vitamin D as an antitumor agent have been hampered by the lack of a suitable pharmaceutical preparation for clinical study. All commercially available formulations are inadequate because of the necessity to administer large numbers of caplets and the poor "bioavailability" of calcitriol (the most carefully studied analogue) at these high doses. Preclinical data suggest that high exposures to calcitriol are necessary for the antitumor effects. Clinical data do indicate that high doses of calcitriol (>100 mcg weekly, intravenously, and 0.15 microg /kg weekly, orally) can be given safely. The maximum tolerated dose of calcitriol is unclear. While a 250-patient trial in men with castration-resistant prostate cancer comparing docetaxel (36 mg/sqm weekly) +/- calcitriol 0.15 microg/kg indicated that calcitriol was very safe may have reduced to death rate, an adequately powered (1000 patients) randomized study of weekly docetaxel + calcitriol versus q3 week docetaxel was negative. The limitations of this trial were the unequal chemotherapy arms compared in this study and the failure to use an optimal biologic dose or maximum-tolerated dose of calcitriol. In view of the substantial preclinical and epidemiologic data supporting the potential role of vitamin D in cancer, careful studies to evaluate the impact of vitamin D replacement on the frequency of cancer and the impact of an appropriate dose and schedule of calcitriol or other active vitamin D analogue on the treatment of established cancer are indicated.

Vitamin D and calcium insufficiency-related chronic diseases: an emerging world-wide public health problem

Vitamin D and calcium insufficiencies are risk factors for multiple chronic diseases. Data from 46 recent studies from Europe, North America, South-East Asia and the South Pacific area clearly indicate that a low vitamin D status and inadequate calcium nutrition are highly prevalent in the general population (30–80%), affecting both genders. The extent of insufficiencies is particularly high in older populations, and in some geographical areas, also in children and in young women of child-bearing age, in ethnic minorities and immigrants, as well as in people of low socio-economic status. Enrichment of cereal grain products with vitamin D and calcium would be a viable approach to increase consumption and improve health outcomes in the general population worldwide.

Vitamin D for the prevention and treatment of pancreatic cancer

Pancreatic cancer is ranked fifth among cancer-related deaths worldwide with a 5-year survival rate of less than 5%. Currently, surgery is the only effective therapy. However, most patients are diagnosed in the late stage and are not suitable for receiving curative surgery. Moreover, pancreatic cancer doesn’t respond well to traditional chemotherapy and radiotherapy, leaving little effective treatment for advanced pancreatic cancer cases. 1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃], the biologically active form of vitamin D₃, was originally identified during studies of calcium and bone metabolism, though it is now recognized that it exerts biological effects in almost every tissue in the body. Abundant evidence has shown that 1α,25(OH)₂D₃ has antiproliferative, apoptotic, pro-differentiation and antiangiogensis effects in many types of cancer cells in vivo and in vitro, including breast, prostate, and colon. Similarly, the antitumor growth effect of 1α,25(OH)₂D₃ on pancreatic cells has been demonstrated. The clinical use of 1α,25(OH)₂D₃ is impeded by the lethal side effects of hypercalcemia and hypercalciuria. Therefore, 1α,25(OH)₂D₃ analogs, which are either equipotent or more potent than 1α,25(OH)₂D₃ in inhibiting tumor cell growth but with fewer hypercalcemic and hypercalciuric side effects, have been developed for the treatment of different cancers. Recently, a pre-clinical study demonstrated that a less calcemic analog of 1α,25(OH)₂D₃, 19-nor-1α,25(OH)₂D₂ (Paricalcitol), is effective in inhibiting tumor growth in vitro and in vivo, via upregulation of p21 and p27 tumor suppressor genes. Studies on the anti-tumor effects of a more potent analog of Paricalcitol are underway. 1α,25(OH)₂D₃ and its analogs are potentially attractive novel therapies for pancreatic cancer.

Serum vitamin D and risk of pancreatic cancer in the prostate, lung, colorectal, and ovarian screening trial

Experimental evidence suggests that vitamin D has anticarcinogenic properties; however, a nested case-control study conducted in a population of male Finnish smokers found that higher 25-hydroxyvitamin D [25(OH)D], the best indicator of vitamin D status as determined by the sun and diet, was associated with a significant 3-fold increased risk for pancreatic cancer. We conducted a nested case-control study in the Prostate, Lung, Colorectal, and Ovarian Screening Trial cohort of men and women 55 to 74 years of age at baseline to test whether prediagnostic serum 25(OH)D concentrations were associated with pancreatic cancer risk. Between 1994 and 2006, 184 incident cases of pancreatic adenocarcinoma occurred (follow-up to 11.7 years). Two controls (n = 368) who were alive at the time the case was diagnosed were selected for each case and matched by age, race, sex, and calendar date of blood draw (to control for seasonal variation). We calculated odds ratios (OR) and 95% confidence intervals (95% CI) using conditional logistic regression, adjusting for smoking and body mass index. Vitamin D concentrations were not associated with pancreatic cancer overall (highest versus lowest quintile, >82.3 versus <45.9 nmol/L: OR, 1.45; 95% CI, 0.66-3.15; P trend = 0.49). However, positive associations were observed among subjects with low estimated annual residential solar UBV exposure, but not among those with moderate to high annual exposure (P interaction = 0.015). We did not confirm the previous strong positive association between 25(OH)D and pancreatic cancer; however, the increased risk among participants with low residential UVB exposure is similar.