Vitamin D Receptor (VDR) Allelic Variants Correlating with Response to Vitamin D3 Supplementation in Breast Cancer Survivors.

We investigated how vitamin D receptor (VDR) allelic variants affect breast cancer survivors' responses to vitamin D3 supplementation to increase circulating 25-hydroxy vitamin D (25(OH)D) levels. Two hundred and fourteen patients who were diagnosed with breast cancer at least 6 mo, prior to the study and had completed all treatment regimens were assigned to consume 4000 IU of vitamin D3 daily for 12 weeks. Linear and multinomial logistic regression analyses were used to analyze the association of VDR single nucleotide polymorphism (SNPs) with changes in circulating 25(OH)D. The TaqI and BsmI VDR sequence variants modified the effect of vitamin D3 treatment on the plasma 25(OH)D changes (P value = 0.008 for TaqI and P value = 0.0005 for BsmI). Patients with the bb [Q4 vs. Q1 odds ratio(OR) 8.04, 95% confidence interval (CI) 1.55-41.57] and tt [Q4 vs. Q1 OR 4.64 95%CI 1.02-21.02] genotype of BsmI and TaqI had larger increases in plasma 25(OH)D levels compared to those with BB and TT genotype respectively after adjustment for potential confounders. Haplotype analyses suggested the existence of specific combination of alleles that might be associated with circulating 25(OH)D changes. VDR allelic variants modulate vitamin D3 supplementation to increase plasma 25(OH) levels in breast cancer survivors.

Assessment the effect of vitamin D supplementation on plasma vitamin D levels, inflammation, and oxidative stress biomarkers based on vitamin D receptor genetic variation in breast cancer survivors: a protocol for clinical trial.

BACKGROUND: Both human genes and environmental exposures, due to complex interplay, play important role in the cancer etiology. Vitamin D is associated with a reduced risk of incidence and mortality of several human cancers. This study will aim to investigate the possible effects of individual polymorphisms in vitamin D receptor (VDR) as well as effects of VDR haplotypes on response to vitamin D supplementation in breast cancer survivors. METHODS: This is an interventional study in which the effects of vitamin D supplementation on plasma vitamin D levels, inflammatory and antioxidant biomarkers and factors associated with cell proliferation, differentiation, damage, and apoptosis will be investigated stratified by variations in VDR genotype. The present study will be conducted on breast cancer survivors referred to the Shohadaye Tajrish hospital and its associated clinics. One hundred ninety-eight breast cancer survivors will receive 4000 IU of vitamin D3 daily for 12 weeks. VDR Fok1, ApaI, TaqI, BsmI, and Cdx-2 genotype will be determined at the end of the study and responses to vitamin D supplements (inflammatory, antioxidant, cell proliferation, differentiation, damage, and apoptosis biomarkers) will be compared between the three subgroups of each VDR polymorphism as well as different VDR haplotype categories. DISCUSSION: Genetic variation is a fundamental factor influencing individuals' divergent responses to diet, nutritional status, metabolic response, and diet-related health disorders. Furthermore, studies of gene and environment interactions will provide a precise and accurate assessments of individuals' dietary requirements by considering both the genetic and environmental aspects simultaneously. The results of the current study, to some extent, will highlight the discrepancies existing in the findings of different studies regarding vitamin D, VDR, and cancer by considering both the genetic and environmental aspects simultaneously. If responses to vitamin D supplementation could be modified by VDR SNPs, determining the distribution of VDR polymorphisms in both breast cancer survivors and healthy populations will provide a new insight into the vitamin D requirements of individuals to prevent cancer and its related mortality based on their genotypes. Trial registration This trial has been registered on Iranian Registry of Clinical Trials (IRCT) under the identification code: IRCT2017091736244N1, registration date: 2017-11-10, http://www.irct.ir/trial/27153.

Effect of vitamin D receptor polymorphisms on plasma oxidative stress and apoptotic biomarkers among breast cancer survivors supplemented vitamin D3.

We investigated whether plasma oxidative stress and apoptotic biomarkers were associated with the VDR polymorphisms in breast cancer survivors supplemented with vitamin D3. Two hundred fourteen breast cancer survivors received 4000 IU of vitamin D3 daily for 12 weeks. Linear regression was used to analyze whether the effect of vitamin D3 supplementation on response variables was associated with the selected VDR single nucleotide polymorphisms executing by 'association' function in the R package 'SNPassoc'. Linear regression analyses adjusted for age, BMI and on-study plasma 25(OH)D changes indicated that the aa genotype of the ApaI [codominant model (aa vs. AA): -0.21 (-0.39 to -0.03); recessive model (aa vs. AA and Aa): -0.20 (-0.37 to -0.03)] and bb genotypes of the BsmI [recessive model (bb vs. BB and Bb): -0.20 (-0.39 to -0.01)] on VDR were associated with greater decrease in plasma Bcl2. Our findings indicated that, the Ff genotype of FokI was accompanied by higher increase in plasma MDA levels [codominant model (Ff vs. FF): 0.64 (0.18-1.11); dominant model (ff and Ff vs. FF): 0.52 (0.09-0.05)]. This observed association was not remained statistically significant after correction for multiple testing. Haplotype score analyses revealed statistically significant association between the FokI BsmI ApaI haplotype and circulating MDA changes (P-value for global score = 0.001) after false-discovery rate correction. Our study suggests that genetic variations in the VDR do not powerfully modify the effects of vitamin D3 intake on biomarkers associated with antioxidant activity, oxidative stress and apoptosis in breast cancer survivors.

Correction to: Vitamin D receptor gene polymorphisms affecting changes in visceral fat, waist circumference and lipid profile in breast cancer survivors supplemented with vitamin D3.

Following publication of the original article [1], the authors reported that one of the co-authors has a mistake in the author name.

Vitamin D receptor gene polymorphisms affecting changes in visceral fat, waist circumference and lipid profile in breast cancer survivors supplemented with vitamin D3.

OBJECTIVE: We investigated whether vitamin D receptor (VDR) polymorphisms are associated with circulating metabolic biomarkers and anthropometric measures changes in breast cancer survivors supplemented with vitamin D3. METHODS: One hundred sixty-eight breast cancer survivors admitted to Shohaday-e-Tajrish hospital received 4000 IU of daily vitamin D3 supplements for 12 weeks. Anthropometric measurements as well dietary, physical activity and plasma metabolic biomarkers assessments were performed before and after intervention. VDR polymorphisms were considered as the main exposures. Multivariate multiple linear regression analyses were used to determine the association between the VDR single-nucleotide polymorphisms (SNPs) and changes in metabolic and anthropometric measures in response to vitamin D3 supplementation. RESULTS: One hundred twenty-five (85%) women had insufficient and inadequate levels of plasma 25-hydroxy vitamin D (25(OH)D) at baseline. Compared to the AA genotype of the ApaI, the aa category showed greater increase in muscle mass [71.3(10.7131.9)] and higher decrease in LDL-C [- 17.9(- 33.6, - 2.3)] levels after adjustment for potential confounders. In addition, the heterozygous genotype (Bb) of the BsmI VDR was associated with higher increase in WC following vitamin D3 supplementation, compared to BB [2.7(0.1,5.3)]. Haplotype score analyses indicate a significant association between inferred haplotypes from BsmI, ApaI, TaqI and FokI, BsmI and Cdx2 VDR polymorphisms and on-study visceral fat changes. CONCLUSIONS: Findings of this study showed that genetic variation in the VDR gene was associated with changes in cardio-metabolic parameters in breast cancer survivors, supplemented with vitamin D3, results could provide a novel insight into better understanding of which subset of individuals benefit most from normalization of vitamin D status. TRIAL REGISTRATION: This trial has been registered on the Iranian Registry of Clinical Trials (IRCT) under the identification code: IRCT2017091736244N1, registration date: 2017-11-10, http://www.irct.ir/trial/27153 and was approved by the ethics committees of the National Nutrition and Food Technology Research Institute (NNFTRI), Shahid Beheshti University of Medical Sciences (SBMU).

Vitamin D Receptor Genetic Variation and Cancer Biomarkers among Breast Cancer Patients Supplemented with Vitamin D3: A Single-Arm Non-Randomized Before and After Trial.

We investigated whether vitamin D receptor (VDR) polymorphisms were associated with cancer biomarkers, i.e., E-cadherin, matrix metallopeptidase 9 (MMP9), interferon ß (IFNß), soluble intercellular adhesion molecule-1 (s-ICAM-1), soluble vascular cell adhesion molecule-1 (s-VCAM-1), tumor necrosis factorα (TNFα), interleukin 6 (IL6), plasminogen activator inhibitor-1(PAI-1), and human high sensitivity C-reactive protein (hs-CRP), among breast cancer survivors who received vitamin D3 supplementation. In a single-arm non-randomized pre- and post trial, 176 breast cancer survivors who had completed treatment protocol including surgery, radio and chemotherapy were enrolled in the study and received 4000 IU of vitamin D3 daily for 12 weeks. The association between the VDR SNPs (ApaI, TaqI, FokI, BsmI and Cdx2) and response variable changes was assessed using linear regression, utilizing the "association" function in the R package "SNPassoc". We observed that women with AA and GA [codominant model (AA compared to GG) and (GA compared to GG); dominant model (AA & GA compared to GG)] genotypes of Cdx2 showed higher increase in plasma MMP9 levels compared to the GG category. In addition, carriers of BsmI bb showed greater decrease in circulating TNFα levels after vitamin D3 supplementation [recessive model (bb compared to BB & Bb]. Likewise, significant associations were identified between haplotypes of VDR polymorphisms and on-study plasma MMP9 changes. However, our results indicate that VDR genetic polymorphisms were not associated with longitudinal changes in the remaining cancer biomarkers. Overall, our findings suggest that changes in certain inflammatory biomarkers in breast cancer survivors with low plasma 25(OH)D levels, supplemented with vitamin D3, may depend on VDR SNPs and haplotypes.