Vitamin D metabolic pathway genes and pancreatic cancer risk

Enhancing the Design of Nutrient Clinical Trials for Disease Prevention-A Focus on Vitamin D: A Systematic Review

OBJECTIVES

This systematic review (SR) highlights principles for nutrient clinical trials and explore the diverse physiological functions of vitamin D beyond its traditional role in the musculoskeletal system related to clinical study designs.

BACKGROUND

Thousands of published research articles have investigated the benefits of vitamin D (a nutrient example taken in this SR) beyond the musculoskeletal system, including the immune, pulmonary, and cardiovascular systems; pregnancy; autoimmune disorders; and cancer. They illustrated vitamin D's molecular mechanisms, interactions, and genomic and nongenomic actions.

METHODS

This SR was designed to identify shortcomings in clinical study designs, statistical methods, and data interpretation that led to inconsistent findings in vitamin D-related publications. SR also highlights examples and insights into avoiding study design errors in future clinical studies, including randomized controlled clinical trials (RCTs). The SR adheres to the latest PRISMA statement, guidelines, and the PICOS process.

RESULTS

Inappropriate or flawed study designs were frequent in clinical trials. Major failures discussed here include too short clinical study duration, inadequate or infrequent doses, insufficient statistical power, failure to measure baseline and achieved levels, and recruiting vitamin D-sufficient participants. These design errors have led to misleading interpretations. Thus, conclusions from such studies should not be generalized or used in guidelines, recommendations, or policymaking.

CONCLUSION

Adequately powered epidemiological studies and RCTs with sufficient vitamin D and duration in individuals with vitamin D deficiency reported favorable clinical outcomes, enriching the literature, enabling to understand its physiology and mechanisms. Proper study designs with rigorous methodologies and cautious interpretation of outcomes are crucial in advancing the nutrient field. The principles discussed apply not only to vitamin D, but also other micro-nutrients and nutraceutical research. Adhering to them enhances the credibility and reliability of clinical trials, SRs, and meta-analysis outcomes. The study emphasizes the importance of focused, hypothesis-driven, well-designed, statistically powered RCTs to explore the diverse benefits of nutrients, conducted in index nutrient deficient participants, and avoidance of study design errors. Findings from such studies should be incorporated into clinical practice, policymaking, and public health guidelines, improving the health of the nation and reducing healthcare costs.

Vitamin D and Pancreatic Ductal Adenocarcinoma-A Review of a Complicated Relationship

INTRODUCTION

From the observation of a negative relationship between UV-B exposure and cancer rates, we hypothesized that vitamin D (VD) may play a protective role in oncogenesis. Moreover, repurposing a well-known and relatively safe drug for conditions with dismal prospects, such as pancreatic ductal adenocarcinoma (PDAC), is a tempting idea. Thus, we aimed to summarize the current knowledge regarding the role of VD in the prevention and treatment of PDAC.

METHODS

We conducted a systematic review of VD and PDAC using Medline-indexed studies accessed through PubMed as the primary data source. This study aimed to identify articles focusing on the role of VD as a risk and prognostic factor for PDAC, mechanistic studies evaluating the effects of VD or vitamin D analogs (VDAs) in PDAC models, and clinical trials on VDAs in PDAC. After the screening, 97 studies were included in the final manuscript.

CONCLUSION

Even though the results from epidemiologic studies were contradictory, basic research has demonstrated that VD can act on PDAC cells either directly, inhibiting proliferation, apoptosis, EMT, migration, invasion, and stemness, or indirectly, through stromal remodeling. A better understanding of the consequences of VD-induced tumor-stroma cross-talk alterations is needed to determine whether VD/VDAs can be used to our own advantage in the treatment of PDAC.

Establishment and validation of a prognostic signature for pancreatic ductal adenocarcinoma based on lactate metabolism-related genes

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancy with poor prognosis. To improve patient outcomes, it is necessary to gain a better understanding of the oncogenesis and progression of this disease. Metabolic reprogramming, particularly the regulation of lactate metabolism, is known to have a significant impact on tumor microenvironment and could provide valuable insights for the management of PDAC patients. In this study, we aimed to investigate the prognostic potential of lactate metabolism-related genes (LMRGs). Methods: Transcriptomic data of patients with PDAC along with the clinical outcomes were retrieved from The Cancer Genome Atlas database, and the expression data in normal pancreas from Genotype-Tissue Expression dataset were adopted as the normal control. By using Cox and LASSO regression models, we identified key genes that are differentially expressed in cancerous tissues and related to prognosis. To determine the prognostic value of LMRGs in PDAC, we evaluated their clinical significance and model performance using both the area under the receiver operator characteristic curve (AUC) and calibration curves. In addition, we evaluated the drug sensitivity prediction and immune infiltration by using oncoPredict algorithm, single sample gene set enrichment analysis and Tumor Immune Estimation Resource. Results: A total of 123 LMRGs were identified through differential gene screening analysis, among which 7 LMRGs were identified to comprise a LMRGs signature that independently predict overall survival of these PDAC patient. The AUC values for the LMRGs signature were 0.786, 0.820, 0.837, and 0.816 for predicting 1-, 2-, 3- and 5-year overall survival respectively. Furthermore, this prognostic signature was used to stratify patients into high-risk and low-risk groups, with the former having worse clinical outcomes. This observation was further validated through analysis of the International Cancer Genome Consortium database. In addition, lower sensitivity to gemcitabine and infiltration of immune effector cells were observed in the cancer tissue of patients in the high-risk group. Conclusion: In conclusion, our data suggests that a genomic signature comprised of these LMRGs may be a novel predictor of overall clinical outcomes and present therapeutic potential for PDAC patients.

Association between Polymorphisms in Vitamin D Pathway-Related Genes, Vitamin D Status, Muscle Mass and Function: A Systematic Review

An association between vitamin D level and muscle-related traits has been frequently reported. Vitamin D level is dependent on various factors such as sunlight exposure and nutrition. But also on genetic factors. We, therefore, hypothesize that single nucleotide polymorphisms (SNPs) within the vitamin D pathway-related genes could contribute to muscle mass and function via an impact on vitamin D level. However, the integration of studies investigating these issues is still missing. Therefore, this review aimed to systematically identify and summarize the available evidence on the association between SNPs within vitamin D pathway-related genes and vitamin D status as well as various muscle traits in healthy adults. The review has been registered on PROSPERO and was conducted following PRISMA guidelines. In total, 77 studies investigating 497 SNPs in 13 different genes were included, with significant associations being reported for 59 different SNPs. Variations in GC, CYP2R1, VDR, and CYP24A1 genes were reported most frequently, whereby especially SNPs in the GC (rs2282679, rs4588, rs1155563, rs7041) and CYP2R1 genes (rs10741657, rs10766197, rs2060793) were confirmed to be associated with vitamin D level in more than 50% of the respective studies. Various muscle traits have been investigated only in relation to four different vitamin D receptor (VDR) polymorphisms (rs7975232, rs2228570, rs1544410, and rs731236). Interestingly, all of them showed only very low confirmation rates (6-17% of the studies). In conclusion, this systematic review presents one of the most comprehensive updates of the association of SNPs in vitamin D pathway-related genes with vitamin D status and muscle traits in healthy adults. It might be used for selecting candidate SNPs for further studies, but also for personalized strategies in identifying individuals at risk for vitamin D deficiency and eventually for determining a potential response to vitamin D supplementation.

Association of Polymorphisms in Vitamin D-Metabolizing Enzymes DHCR7 and CYP2R1 with Cancer Susceptibility: A Systematic Review and Meta-Analysis

The deficiency of vitamin D has been reported to be relevant to cancer risk. DHCR7 and CYP2R1 are crucial components of vitamin D-metabolizing enzymes. Thus, accumulating researchers are concerned with the correlation between polymorphisms of DHCR7 and CYP2R1 genes and cancer susceptibility. Nevertheless, the conclusions of literatures are inconsistent. We conducted an integrated review for the correlation of DHCR7 and CYP2R1 SNPs with cancer susceptibility. In the meanwhile, a meta-analysis was performed using accessible data to clarify the association between DHCR7 and CYP2R1 SNPs and overall cancer risk. Literatures which meet the rigid inclusion and exclusion criteria were involved. The association of each SNP with cancer risk was calculated by odds ratios (ORs). 12 case-control designed studies covering 23780 cases and 27307 controls were ultimately evolved in the present meta-analysis of five SNPs (DHCR7 rs12785878 and rs1790349 SNP; CYP2R1 rs10741657, rs12794714, and rs2060793 SNP). We found that DHCR7 rs12785878 SNP was significantly related to cancer risk in the whole population, Caucasian subgroup, and hospital-based (HB) subgroup. DHCR7 rs1790349 SNP was analyzed to increase cancer risk in Caucasians. Moreover, CYP2R1 rs12794714-A allele had correlation with a lower risk of colorectal cancer. Our findings indicated that rs12785878, rs1790349, and rs12794714 SNPs might potentially be biomarkers for cancer susceptibility.

Age-adjusted mortality from pancreatic cancer increased NINE-FOLD in japan from 1950 to 1995 - Was a low-protein quasi-vegan diet a key factor in their former low risk?

During the last half of the twentieth century, age-adjusted mortality from pancreatic cancer in Japan rose about nine-fold in both sexes. Well-characterized risk factors such as smoking, obesity/metabolic syndrome, and heavy alcohol use appear to explain only a modest part of this rise. It is proposed that a diet relatively low in protein, and particularly low in animal protein, was a key determinant of the low risk for pancreatic cancer in mid-century Japan. It is further proposed that pancreatic acinar cells, owing to their extraordinarily high rate of protein synthesis, are at high risk for ER stress; that such stress plays a fundamental role in the induction of most pancreatic cancers; and that low-protein diets help to offset such stress by modulating activities of the kinases GCN2 and mTORC1 while increasing autocrine and systemic production of fibroblast growth factor 21. This model appears to clarify the role of various risk factors and protective factors in pancreatic cancer induction. A vegan or quasi-vegan low-protein diet may have broader potential for decreasing risk for a range of common "Western" cancers.

Bioinformatics for The Prognostic Value and Function of Cubilin (CUBN) in Colorectal Cancer

Background

Cubilin (CUBN) gene was reported to be a novel risk variant for colorectal cancer (CRC). Previous studies have shown that germline variants in known cancer driver genes are predictive of patient outcome, but no study has systematically analyzed CRC to identify CUBN that can predict patient outcome and function by using bioinformatics.

Material/Methods

The association in expression, clinicopathological parameters, and survival were analyzed by using Oncomine, UNCLA, and GEPIA, while CUBN alterations and related functional networks were identified using cBioPortal. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathways (KEGG) of CUBN in CRC were explored by using LinkOmics. Gene set enrichment analysis (GSEA) examined target networks of kinases, miRNAs, and transcription factors.

Results

We found that CUBN was overexpressed in CRC. Patients who were in advanced TNM stage tended to express higher CUBN mRNA levels, while those who received radiotherapy tended to express relatively lower CUBN mRNA levels. Higher expression of CUBN was found to be associated with shorter overall survival (OS) and disease-free survival (DFS). Moreover, functional networks analysis suggested that CUBN can regulate mismatch repair, terpenoid backbone biosynthesis, base excision repair, and proteasome via vitamin digestion and absorption pathway to influence CRC occurrence.

Conclusions

These findings suggested that CUBN could serve as a prognostic and therapeutic biomarker of CRC in the future.

A systematic review and network meta-analysis of single nucleotide polymorphisms associated with pancreatic cancer risk

In this meta-analysis, we systematically investigated the correlation between single nucleotide polymorphisms (SNPs) and pancreatic cancer (PC) risk. We searched PubMed, Network Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), China Science and Technology Periodical Database (VIP), and Wanfang databases up to January 2020 for studies on PC risk-associated SNPs. We identified 45 case-control studies (36,360 PC patients and 54,752 non-cancer individuals) relating to investigations of 27 genes and 54 SNPs for this meta-analysis. Direct meta-analysis followed by network meta-analysis and Thakkinstian algorithm analysis showed that homozygous genetic models for CTLA-4 rs231775 (OR =0.326; 95% CI: 0.218-0.488) and VDR rs2228570 (OR = 1.976; 95% CI: 1.496-2.611) and additive gene model for TP53 rs9895829 (OR = 1.231; 95% CI: 1.143-1.326) were significantly associated with PC risk. TP53 rs9895829 was the most optimal SNP for diagnosing PC susceptibility with a false positive report probability < 0.2 at a stringent prior probability value of 0.00001. This systematic review and meta-analysis suggest that TP53 rs9895829, VDR rs2228570, and CTLA-4 rs231775 are significantly associated with PC risk. We also demonstrate that TP53 rs9895829 is a potential diagnostic biomarker for estimating PC risk.

A comprehensive assessment of single nucleotide polymorphisms associated with pancreatic cancer risk: A protocol for systematic review and network meta-analysis

BACKGROUND

Single nucleotide polymorphisms (SNPs) have been inconsistently associated with pancreatic cancer (PC) risk. This meta-analysis aimed to synthesize relevant data on SNPs associated with PC.

METHODS

Databases were searched to identify association studies of SNPs and PC published through January 2020 from the databases of PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, the Chinese Science and Technology Periodical Database (VIP) and Wanfang databases. Network meta-analysis and Thakkinstian algorithm were used to select the most appropriate genetic model, along with false positive report probability (FPRP) for noteworthy associations. The methodological quality of data was assessed based on the STREGA statement Stata 14.0 will be used for systematic review and meta-analysis.

RESULTS

This study will provide a high-quality evidence to find the SNP most associated with pancreatic cancer susceptibility and the best genetic model.

CONCLUSIONS

This study will explore which SNP is most associated with pancreatic cancer susceptibility.Registration: INPLASY202040023.

Anticancer activity of vitamin D – molecular mechanisms

A large number of studies have pointed to the relations between blood levels of 25-hydroxy vitamin D with cancer incidence and survival. The phenomenon of the multidirectional activity of vitamin D is possibly due to the presence of VDR in most nonskeletal human cells, including cancer cells. A wide range of the genes regulated by VDR are related with cell proliferation, apoptosis, differentiation, angiogenesis and metastasis. In some preclinical studies, colon, lung and BC have all demonstrated downregulation of VDR expression as compared to normal cells, and well-differentiated tumors have shown more VDR expression when compared to their poorly differentiated counterparts. Generally, higher tumor VDR expression has been noted as correlating with better prognosis in cancer patients. However, vitamin D pathway genetic polymorphisms also may influence cancer risk. VDR polymorphisms have received the most attention, but this influence has also been observed in genes related to vitamin D metabolism or signalling, such as: CYP27B1, CYP24A1, VDBP or RXRA. Even though the associations between most of them and cancers were not significant, some studies show that VDR polymorphisms may be a better or poor prognostic factor to assess the risk of cancer. The aim of this paper was to present the molecular pathways affected by vitamin D, which are included in carcinogenesis. The literature survey comprised of research compiled from mostly the last five years and it proves vitamin D as the most phenomenal among other vitamins.

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 Variants in Group-Specific Component (GC) Gene Are Associated with Breast Cancer Risk among Chinese Women

The group-specific component (GC) gene, one of the vitamin D pathway genes, seems to play an important role in cancer development. A population-based breast cancer study including 818 cases and 935 controls in a Chinese population was carried out to evaluate the potential associations of four polymorphisms (rs16847024, rs17467825, rs2298850, and rs3755967) in the GC gene with risk of breast cancer. We detected three SNPs with statistically significant effects on breast cancer development after adjusting for age, menopausal status, body mass index (BMI), family history of breast cancer, income, waist circumference, and education (rs17467825: adjusted OR = 0.80, 95% CI = 0.65–0.99; rs2298850: adjusted OR = 0.80, 95% CI = 0.65–0.98; rs3755967: adjusted OR = 0.80, 95% CI = 0.65–0.98). Stratified analysis found that when an individual had a waist circumference <80 cm, rs17467825, rs2298850, and rs3755967 could markedly reduce the risk of breast cancer. Significant interactions between polymorphisms of rs2298850 and rs3755967 and waist circumference were also observed for breast cancer risk. Combined analysis revealed a significant association among the allele numbers of protective effects with decreased breast cancer risk (P_trend=0.043). These results indicated that, in the GC gene, genetic mutations might be related to breast cancer susceptibility in Chinese women.

Association of serum level of vitamin D and VDR polymorphism Fok1 with the risk or survival of pancreatic cancer in Egyptian population

BACKGROUND AND AIMS

Pancreatic cancer (PC) is the fourth most common cause of death from cancer in Egypt. Few studies have been conducted to assess the relationship between vitamin D serum level and vitamin D receptor (VDR) polymorphisms with the survival of PC patients. This is the first study in Egypt to investigate the association of the status of vitamin D serum level and genotypic distribution of single nucleotide polymorphisms (SNP) Fok1 with the risk of developing PC and whether they could detect survival or not.

PATIENTS AND METHODS

The study included a total of 47 PC cases that were histopathologically proven to have PC, and 37 controls that were attending at the same time for investigation but proved that they were all PC free. Pre-diagnostic concentrations of vitamin D and VDR polymorphism Fok1 were assessed from all participants in the study.

RESULTS

There was a 1.5-fold increase in the serum level of vitamin D in PC patients when compared to non-PC subjects. Regarding VDR Fok1, polymorphism distribution in PC was CC (Wild Type) 26 (55.3%), CT 16 (34%), and TT 5 patients (10.7%). For the control group, CC was found in 24 (64.8%), CT in 12 (32.4%), and TT genotype was found only in one individual 1 (2.8%) with no statistically significant difference between the two studied groups (P 0.72).

CONCLUSION

Low serum vitamin D or VDR-SNP is not a risk factor for PC in Egyptian patients. Recommendations to increase vitamin D concentrations in healthy persons for the prevention of cancer and improving overall survival should be carefully considered.

Genetic variants in the platelet-derived growth factor subunit B gene associated with pancreatic cancer risk

The platelet-derived growth factor (PDGF) signaling pathway plays important roles in development and progression of human cancers. In our study, we aimed to identify genetic variants of the PDGF pathway genes associated with pancreatic cancer (PC) risk in European populations using three published genome-wide association study datasets, which consisted of 9,381 cases and 7,719 controls. The expression quantitative trait loci (eQTL) analysis was also performed using data from the 1000 Genomes, TCGA and GTEx projects. As a result, we identified two potential susceptibility loci (rs5757573 and rs6001516) of PDGFB associated with PC risk [odds ratio (OR) = 1.10, 95% confidence interval (CI) = 1.05-1.16, and p = 4.70 × 10-5 for the rs5757573 C allele and 1.21, 1.11-1.32, and 2.01 × 10-5 for the rs6001516 T allele]. Haplotype analysis revealed that the C-T haplotype carriers had a significantly increased risk of PC than those carrying the T-C haplotype (OR = 1.23, 95% CI = 1.12-1.34, p =5.00 × 10-6 ). The multivariate regression model incorporating the number of unfavorable genotypes (NUGs) with age and sex showed that carriers with 1-2 NUGs, particularly among 60-70 age group or males, had an increased risk of PC, compared to those without NUG. Furthermore, the eQTL analysis revealed that both loci were correlated with a decreased mRNA expression level of PDGFB in lymphoblastoid cell lines and pancreatic tumor tissues (p = 0.015 and 0.071, respectively). Our results suggest that genetic variants in PDGFB may play a role in susceptibility to PC. Further population and functional validations of our findings are warranted.

Vitamin D and Cancer Risk and Mortality: State of the Science, Gaps, and Challenges

There has been substantial enthusiasm recently regarding the potential role of vitamin D in the primary and secondary prevention of cancer. Laboratory studies demonstrate a range of anticarcinogenic effects for vitamin D compounds, but human studies have yielded little consistent evidence supporting a protective association. Higher circulating levels of vitamin D (i.e., 25-hydroxyvitamin D or 25(OH)D) appear to be associated with reduced risk of colorectal and bladder malignancies, but higher risk of prostate and possibly pancreatic cancers, with no clear association for most other organ sites examined. Despite there being no official institutional recommendations regarding the use of vitamin D supplements for cancer prevention, screenings for vitamin D deficiency and vitamin D supplement use have increased substantially over the past decade. These widespread practices demonstrate that population sociobehavioral changes are often adopted before scientifically well-informed policies and recommendations are available. This review critically examines the currently available epidemiologic literature regarding the associations between circulating 25(OH)D, vitamin D supplementation, and vitamin D-related genetic variation and cancer risk and mortality, with a particular emphasis on prospective studies. We identify several important gaps in our scientific knowledge that should be addressed in order to provide sufficient reproducible data to inform evidence-based recommendations related to optimal 25(OH)D concentrations (and any role for vitamin D supplementation) for the primary and secondary prevention of cancer. With few exceptions, such recommendations cannot be made at this time.

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.

Design and implementation of a custom next generation sequencing panel for selected vitamin D associated genes

Background

Biologically active vitamin D has an important regulatory role within the genome. It binds the vitamin D receptor (VDR) in order to control the expression of a wide range of genes as well as interacting with the epigenome to modify chromatin and methylation status. Vitamin D deficiency is associated with several human diseases including end-stage renal disease.

Methods

This article describes the design and testing of a custom, targeted next generation sequencing (NGS) panel for selected vitamin D associated genes. Sequencing runs were used to determine the effectiveness of the panel for variant calling, to compare efficiency and data across different sequencers, and to perform representative, proof of principle association analyses. These analyses were underpowered for significance testing. Amplicons were designed in two pools (163 and 166 fragments respectively) and used to sequence two cohorts of renal transplant recipients on the Ion Personal Genome Machine (PGM)™ and Ion S5™ XL desktop sequencers.

Results

Coverage was provided for 43.8 kilobases across seven vitamin D associated genes (CYP24A1, CUBN, VDR, GC, NADSYN1, CYP27B1, CYP2R1) as well as 38 prioritised SNPs. Sequencing runs provided sufficient sequencing quality, data output and validated the effective library preparation and panel design.

Conclusions

This novel, custom-designed, validated panel provides a fast, cost effective, and specific approach for the analysis of vitamin D associated genes in a wide range of patient cohorts. This article does not report results from a controlled health-care intervention.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-017-2664-z) contains supplementary material, which is available to authorized users.

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.

SNP rs11185644 of RXRA gene is identified for dose-response variability to vitamin D3 supplementation: a randomized clinical trial

The level of serum 25-Hydroxyvitamin D [25(OH)D] has high heritability, suggesting that genes may contribute to variations in serum 25(OH)D level and vitamin D dose-response. As vitamin D deficiency has been linked to numerous diseases, understanding how genetic variation contributes to vitamin D dose-response is important for personalized vitamin D treatment and cost-effective disease prevention. To identify genetic variants responsible for vitamin D status and dose-response, we performed two vitamin D3 and calcium clinical supplementation trials in 2,207 postmenopausal Caucasian women. We examined the association of 291 SNPs with baseline serum 25(OH)D levels and 25(OH)D dose-response. Five SNPs, rs10500804 (P = 4.93 × 10⁻⁷), rs2060793 (P = 6.63 × 10⁻⁷), rs10741657 (P = 1.49 × 10⁻⁶), rs10766197 (P = 1.05 × 10⁻⁵) and rs11023380 (P = 7.67 × 10⁻⁵) in the CYP2R1 gene, as well as 6 SNPs, rs4588 (P = 7.86 × 10⁻⁷), rs2298850 (P = 1.94 × 10⁻⁶), rs1155563 (P = 6.39 × 10⁻⁶), rs705119 (P = 2.80 × 10⁻⁵), rs705120 (P = 1.08 × 10⁻⁴) and rs222040 (P = 1.59 × 10⁻⁴) in the GC gene were associated with baseline serum 25(OH)D levels. SNP rs11185644 near the RXRA was significantly associated with 25(OH)D dose-response (P = 1.01 × 10⁻⁴). Our data suggest that polymorphisms in the CYP2R1 and GC gene may contribute to variation in baseline serum 25(OH)D concentration, and that polymorphism rs11185644 may contribute to variation in 25(OH)D dose-response in healthy postmenopausal Caucasian women.

Vitamin D-Related Gene Polymorphisms, Plasma 25-Hydroxy-Vitamin D, Cigarette Smoke and Non-Small Cell Lung Cancer (NSCLC) Risk

Epidemiological studies regarding the relationship between vitamin D, genetic polymorphisms in the vitamin D metabolism, cigarette smoke and non-small cell lung cancer (NSCLC) risk have not been investigated comprehensively. To search for additional evidence, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and radioimmunoassay method were utilized to evaluate 5 single-nucleotide polymorphisms (SNPs) in vitamin D receptor (VDR), 6 SNPs in 24-hydroxylase (CYP24A1), 2 SNPs in 1α-hydroxylase (CYP27B1) and 2 SNPs in vitamin D-binding protein (group-specific component, GC) and plasma vitamin D levels in 426 NSCLC cases and 445 controls from China. Exposure to cigarette smoke was ascertained through questionnaire information. Multivariable linear regressions and mixed effects models were used in statistical analysis. The results showed that Reference SNP rs6068816 in CYP24A1, rs1544410 and rs731236 in VDR and rs7041 in GC were statistically significant in relation to reduction in NSCLC risk (p < 0.001-0.05). No significant connection was seen between NSCLC risk and overall plasma 25-hydroxyvitamin D [25(OH)D] concentrations, regardless of smoking status. However, the mutation genotype of CYP24A1 rs6068816 and VDR rs1544410 were also significantly associated with increased 25(OH)D levels only in both the smoker and non-smoker cases (p < 0.01-0.05). Meanwhile, smokers and non-smokers with mutated homozygous rs2181874 in CYP24A1 had significantly increased NSCLC risk (odds ratio (OR) = 2.14, 95% confidence interval (CI) 1.47-3.43; p = 0.031; OR = 3.57, 95% CI 2.66-4.74; p = 0.019, respectively). Smokers with mutated homozygous rs10735810 in VDR had significantly increased NSCLC risk (OR = 1.93, 95% CI 1.41-2.76; p = 0.015). However, smokers with mutated homozygous rs6068816 in CYP24A1 had significantly decreased NSCLC risk (OR = 0.43, 95% CI 0.27-1.02; p = 0.006); and smokers and non-smokers with mutated homozygous rs1544410 in VDR had significantly decreased NSCLC risk (OR = 0.51, 95% CI 0.34-1.17; p = 0.002; OR = 0.26, 95% CI 0.20-0.69; p = 0.001, respectively). There are significant joint effects between smoking and CYP24A1 rs2181874, CYP24A1 rs6068816, VDR rs10735810, and VDR rs1544410 (p < 0.01-0.05). Smokers with mutated homozygous rs10735810 in VDR had significantly increased NSCLC risk (OR = 1.93, 95% CI 1.41-2.76; p = 0.015). In summary, the results suggested that the lower the distribution of vitamin D concentration, the more the genetic variations in CYP24A1, VDR and GC genes may be associated with NSCLC risk. In addition, there are significant joint associations of cigarette smoking and vitamin D deficiency on NSCLC risk.

Efficient Software for Multi-marker, Region-Based Analysis of GWAS Data

Genome-wide association studies (GWAS) have associated many single variants with complex disease, yet the better part of heritable complex disease risk remains unexplained. Analytical tools designed to work under specific population genetic models are needed. Rare variants are increasingly shown to be important in human complex disease, but most existing GWAS data do not cover rare variants. Explicit population genetic models predict that genes contributing to complex traits and experiencing recurrent, unconditionally deleterious, mutation will harbor multiple rare, causative mutations of subtle effect. It is difficult to identify genes harboring rare variants of large effect that contribute to complex disease risk via the single marker association tests typically used in GWAS. Gene/region-based association tests may have the power detect associations by combining information from multiple markers, but have yielded limited success in practice. This is partially because many methods have not been widely applied. Here, we empirically demonstrate the utility of a procedure based on the rank truncated product (RTP) method, filtered to reduce the effects of linkage disequilibrium. We apply the procedure to the Wellcome Trust Case Control Consortium (WTCCC) data set, and uncover previously unidentified associations, some of which have been replicated in much larger studies. We show that, in the absence of significant rare variant coverage, RTP based methods still have the power to detect associated genes. We recommend that RTP-based methods be applied to all existing GWAS data to maximize the usefulness of those data. For this, we provide efficient software implementing our procedure.

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.

Vitamin D and pancreatic cancer

Pancreatic cancer is currently the fourth leading cause of cancer-related death, and it is projected that within the next two decades it will become the second most common cause of death due to cancer. Few patients are diagnosed when surgical resection is feasible and the efficacy of existing chemotherapeutic agents for advanced/metastatic cancer is limited. Thus, there is a need to identify agents that can prevent pancreatic cancer or improve survival in those affected. Vitamin D and its analogues, with their ability to regulate cell growth, differentiation, apoptosis and angiogenesis, may be promising agents. This review explores the published literature about the potential role of vitamin D and its analogues in preventing or treating pancreatic cancer. The vitamin D system is altered in pancreatic cancer. Pancreatic cancer tissue expresses vitamin D receptors, but the calcitriol analogues may affect pancreatic cancer tissue by mechanisms that do not involve interaction with its receptors. Experimental evidence postulates multiple potential mechanisms by which calcitriol analogues may exert their anti-cancer effect, the most common being by action on cyclin-dependent kinases p21 and p27. Use of calcitriol analogues in pancreatic cancer remains largely underexplored and warrants further clinical trials.

Genetics and Genetic Testing in Pancreatic Cancer

Genetic testing of germline DNA is used in patients suspected of being at risk of pancreatic ductal adenocarcinoma (PDAC) to better define the individual's risk and to determine the mechanism of risk. A high genetic risk increases the pretest probability that a biomarker of early cancer is a true positive and warrants further investigation. The highest PDAC risk is generally associated with a hereditary predisposition. However, the majority of PDAC results from complex, progressive gene-environment interactions that currently fall outside the traditional risk models. Over many years, the combination of inflammation, exposure to DNA-damaging toxins, and failed DNA repair promote the accumulation of somatic mutations in pancreatic cells; PDAC risk is further increased by already present oncogenic germline mutations. Predictive models and new technologies are needed to classify patients into more accurate and mechanistic PDAC risk categories that can be linked to improved surveillance and preventative strategies.