The impact of vitamin D in breast cancer: genomics, pathways, metabolism

An analysis of the association between breast density and body mass index with breast cancer molecular subtypes in early breast cancer: data from a Spanish population

PURPOSE

Breast cancer is an important health problem, like obesity and dyslipidemia, with a strong association between body mass index (BMI) and breast cancer incidence and mortality. The risk of breast cancer is also high in women with high mammographic breast density (MBD). The purpose of this study was to analyze the association between BMI and MBD according to breast cancer molecular subtypes.

METHODS

This transversal, descriptive, multicenter study was conducted at three Spanish breast cancer units from November 2019 to October 2020 in women with a recent diagnosis of early breast cancer. Data were collected at the time of diagnosis.

RESULTS

The study included 162 women with a recent diagnosis of early breast cancer. The median age was 52 years and 49.1% were postmenopausal; 52% had normal weight, 32% overweight, and 16% obesity. There was no association between BMI and molecular subtype but, according to menopausal status, BMI was significantly higher in postmenopausal patients with luminal A (p = 0.011) and HER2-positive (p = 0.027) subtypes. There was no association between MBD and molecular subtype, but there were significant differences between BMI and MBD (p < 0.001), with lower BMI in patients with higher MBD. Patients with higher BMI had lower HDL-cholesterol (p < 0.001) and higher insulin (p < 0.001) levels, but there were no significant differences in total cholesterol or vitamin D.

CONCLUSIONS

This study showed higher BMI in luminal A and HER2-positive postmenopausal patients, and higher BMI in patients with low MBD regardless of menopausal status.

The Impact of Vitamin D and Its Dietary Supplementation in Breast Cancer Prevention: An Integrative Review

Vitamin D deficiency is currently a significant public health issue closely linked to numerous diseases, such as breast cancer. This study aims to determine the estimated optimal serum levels of vitamin D to have a protective effect against breast cancer, in addition to exploring the biological mechanisms and risk factors involved. A literature search of articles published in the last 5 years was conducted, and simple statistical analyses using mean and standard deviation were performed to calculate the average concentration of vitamin D from different available studies. It has been observed that serum levels of vitamin D ≥ 40.26 ng/mL ± 14.19 ng/mL could exert a protective effect against breast cancer. Additionally, various biological mechanisms, such as those related to the immune system, and risk factors like diet implicated in this relationship were elucidated. Consequently, it can be concluded that proper serum levels of vitamin D may have a protective effect against breast cancer, and dietary supplementation may be an appropriate procedure to achieve these optimal vitamin D concentrations.

Plasma 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Levels in Breast Cancer Risk in Mali: A Case-Control Study

(1) Background: Breast cancer is the most prevalent cancer found in women in Mali. The aim of the current study was to determine the association between metabolites circulating in the blood, 25(OH)D and 1,25(OH)2D, and vitamin D levels with the risk of breast cancer in Malian women. (2) Methods: We conducted a prospective case-control study from August 2021 to March 2022. Control subjects were matched to cases according to age (within 5 years). The patients' clinical stage was determined by the oncologist according to the tumour-nodes-metastasis (TNM) classification system. (3) Results: We observed no differences in the mean 25(OH)D (p = 0.221) and 1,25(OH)2D (p = 0.285) between cases and controls. However, our findings indicate a more pronounced inverse association in the first level of plasma 25(OH)D, while the risk function decreases at higher levels. This observation takes strength with 1,25(OH)2D by a significant association between the first quartile and breast cancer as a risk factor (p = 0.03; OR = 71.84; CI: 1.36-3785.34). (4) Conclusions: These outcomes showed a possible association between 25(OH)D and 1,25(OH)2D in decreasing the risk of breast cancer.

Natural products derived from medicinal plants and microbes might act as a game-changer in breast cancer: a comprehensive review of preclinical and clinical studies

Breast cancer (BC) is the most prevalent neoplasm among women. Genetic and environmental factors lead to BC development and on this basis, several preventive - screening and therapeutic interventions have been developed. Hormones, both in the form of endogenous hormonal signaling or hormonal contraceptives, play an important role in BC pathogenesis and progression. On top of these, breast microbiota includes both species with an immunomodulatory activity enhancing the host's response against cancer cells and species producing proinflammatory cytokines associated with BC development. Identification of novel multitargeted therapeutic agents with poly-pharmacological potential is a dire need to combat advanced and metastatic BC. A growing body of research has emphasized the potential of natural compounds derived from medicinal plants and microbial species as complementary BC treatment regimens, including dietary supplements and probiotics. In particular, extracts from plants such as Artemisia monosperma Delile, Origanum dayi Post, Urtica membranacea Poir. ex Savigny, Krameria lappacea (Dombey) Burdet & B.B. Simpson and metabolites extracted from microbes such as Deinococcus radiodurans and Streptomycetes strains as well as probiotics like Bacillus coagulans and Lactobacillus brevis MK05 have exhibited antitumor effects in the form of antiproliferative and cytotoxic activity, increase in tumors' chemosensitivity, antioxidant activity and modulation of BC - associated molecular pathways. Further, bioactive compounds like 3,3'-diindolylmethane, epigallocatechin gallate, genistein, rutin, resveratrol, lycopene, sulforaphane, silibinin, rosmarinic acid, and shikonin are of special interest for the researchers and clinicians because these natural agents have multimodal action and act via multiple ways in managing the BC and most of these agents are regularly available in our food and fruit diets. Evidence from clinical trials suggests that such products had major potential in enhancing the effectiveness of conventional antitumor agents and decreasing their side effects. We here provide a comprehensive review of the therapeutic effects and mechanistic underpinnings of medicinal plants and microbial metabolites in BC management. The future perspectives on the translation of these findings to the personalized treatment of BC are provided and discussed.

Pathology-supported genetic testing for the application of breast cancer pharmacodiagnostics: family counselling, lifestyle adjustments and change of medication

BACKGROUND

Pathology-supported genetic testing (PSGT) enables transitioning of risk stratification from the study population to the individual.

RESEARCH DESIGN AND METHODS

We provide an overview of the translational research performed in postmenopausal breast cancer patients at increased risk of osteoporosis due to aromatase inhibitor therapy, as the indication for referral. Both tumour histopathology and blood biochemistry levels were assessed to identify actionable disease pathways using whole exome sequencing (WES).

RESULTS

The causes and consequences of inadequate vitamin D levels as a modifiable risk factor for bone loss were highlighted in 116 patients with hormone receptor-positive breast cancer. Comparison of lifestyle factors and WES data between cases with vitamin D levels at extreme upper and lower ranges identified obesity as a major discriminating factor, with the lowest levels recorded during winter. Functional polymorphisms in the vitamin D receptor gene contributed independently to therapy-related osteoporosis risk. In a patient with invasive lobular carcinoma, genetic counselling facilitated investigation of the potential modifying effect of a rare CDH1 variant co-occurring withBRCA1 c.66dup (p.Glu23ArgfsTer18).

CONCLUSION

Validation of PSGT as a three-pronged pharmacodiagnostics tool for generation of adaptive reports and data reinterpretation during follow-up represents a new paradigm in personalised medicine, exposing significant limitations to overcome.

Association of vitamin D deficiency and inflammatory cytokines with the clinicopathological features of breast cancer in female Saudi patients

Breast cancer is the leading cause of cancer-related death among women in Saudi Arabia. Many studies have suggested a strong correlation between vitamin D and multiple types of cancer. This study included 100 female Saudi patients with early or locally advanced breast cancer. Patients were recruited from King Faisal Hospital in Taif City, Saudi Arabia, from January 2020 to September 2020. We aimed to study the association between serum vitamin D, calcium, interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α) and chemerin and breast cancer progression. The control group consisted of 100 healthy individuals. Serum levels of vitamin D, calcium, IL-6, TNF-α and chemerin were measured in all participants. Vitamin D was significantly decreased in patients with high-grade tumours ( p < 0.0001), obesity ( p = 0.013), negative oestrogen receptors ( p < 0.0001), negative progesterone receptors ( p < 0.0001) and positive HER2 receptors ( p < 0.0001). Vitamin D was also decreased in patients with large tumours ( p < 0.0001), axillary lymph node involvement ( p < 0.0001) and advanced-stage cancers ( p < 0.0001). Moreover, higher levels of IL-6, TNF-α and chemerin were significantly associated with the presence of breast cancer, particularly in its advanced stages. Vitamin D deficiency and elevated levels of IL-6, TNF- α and chemerin were associated with adverse clinicopathological features of breast cancer. Vitamin D deficiency and elevated inflammatory cytokines (IL-6, TNF-α and chemerin) were associated with the clinicopathological features of breast cancer in female Saudi patients.

The Association of Intra-Tumoral and Stromal Vitamin D Receptor (VDR) Expressions with Molecular Subtypes and Clinicopathological Factors in Breast Carcinoma

OBJECTIVE

This study aimed to investigate the association between intra-tumoral and stromal VDR expressions with molecular subtypes and clinicopathological factors.

METHODS

A total of 75 formalin-fixed paraffin embedded tissue samples were stained using immunohistochemical methods. The VDR expressions were measured by counting brown-stained nuclei in intra-tumoral and stromal areas. The association of VDR expression with molecular subtypes and clinopathological factors was examined. Statistical analysis was performed by chi square tests.

RESULTS

High intra-tumoral VDR expression was found in carcinomas with luminal molecular subtypes (p=0.039) and low histological degrees (p=0.035). High VDR expression in the stroma was found in breast carcinomas with large tumor sizes.

CONCLUSIONS

High intra-tumoral VDR expression is found in breast carcinomas with luminal subtypes and low histological grade (I/II). Both factors are known to have a good prognosis. These findings further strengthen the function of VDR as anti-tumorigenesis.

The Comparison of 25-Hydroxyvitamin D3 between Patients With and Without Cervical Cancer

BACKGROUND: Vitamin D was currently believed to have effects on numerous cancer pathogenic processes. AIM: This study was to assess the correlation of Vitamin D serum level in women with carcinoma cervix and also evaluate the effect of carcinoma cervix on the Vitamin D serum. METHODS: This was an observational with a cross-sectional study. Participants were women with cervical cancer who have not received any treatment, presented to the Oncology Clinic of the Obstetrics and Gynecology Department of Dr. Hasan Sadikin General Hospital, and women without cervical cancer. The level of Vitamin D3 was analyzed in the Serology Laboratory of Clinical Pathology Department of Dr. Hasan Sadikin General Hospital. RESULTS: There were 113 participants consisted of 58 women with cervical cancer and 55 healthy women. Mean levels of Vitamin D3 were significantly lower in cervical cancer group than non-cervical cancer group (26.74 ± 13.166 vs. 32.16±14.86, p = 0.022). CONCLUSION: The level of Vitamin D3 was found to be significantly higher in the non-cervical cancer group than cervical cancer group.

Association of vitamin D deficiency and insulin resistance with breast cancer in premenopausal Algerian women: A cross-sectional study

BACKGROUND

Low 25(OH)D levels are mainly related to breast cancer (BC) risk in postmenopausal women, while the impact of insulin resistance (IR) on BC prognosis is controversial.

OBJECTIVE

Considering the high prevalence of BC in younger Algerian women, this cross-sectional study analyzed whether vitamin D status and IR are biomarkers for breast tumor status in premenopausal women.

METHODS

In 96 women (mean age, 40.96±0.65years) newly diagnosed with BC, tumor status was determined immunohistochemically, classified by molecular subtype, then correlated with body-mass index, total plasma 25(OH)D, insulin and glucose levels and HOMA-IR, using chi², Student t, Spearman and ANOVA tests and multivariate logistic regression.

RESULTS

66 of the 98 patients (68.75%) showed vitamin D deficiency (9.74ng/mL). Overweight and obese patients with HOMA-IR >2.5, positive for HER2 and with high Ki-67 index had the most severe vitamin D deficiency. There was a significant association between vitamin D deficiency, high Ki-67 index (OR, 14.55; 95% CI, 3.43-82.59; p=0.00078) and IR (OR, 4.99; 95% CI, 1.27-24.47; p=0.03), and between IR and HER2-positivity (OR, 3.23; 95% CI, 1.05-10.56; p=0.04).

CONCLUSIONS

Vitamin D deficiency and IR are potential biomarkers for poorer prognosis in BC patients, independently of and/or synergically with high Ki-67 index and HER2-positivity in premenopausal overweight or obese women. The potential relationship of vitamin D receptor gene expression with breast cancer survival in Algerian patients will be investigated in a large cohort.

Occupational exposure to solar ultraviolet B radiation and risk of subtypes of breast cancer in Danish women

OBJECTIVES

Previous epidemiological studies have indicated that solar ultraviolet B radiation (UVR) may have a protective effect on breast cancer. However, the evidence remains inconclusive. Despite the fact that outdoor work history may be considered a reliable measure of long-term UVR exposure, objective information on lifetime employment has not been included in previous investigations focusing on breast cancer. To address this issue, we explored the association between occupational UVR exposure and female breast cancer, including subtypes.

METHODS

A total of 38 375 women under the age of 70 years were identified with primary breast cancer using the Danish Cancer Registry. Five female controls born on the same year, alive and free of breast cancer at the time of diagnosis of the index case, were randomly selected from the Danish Civil Registration System. The Danish Supplementary Pension Fund Register was used to retrieve full employment history, and a job exposure matrix was used to assess occupational UVR exposure. Conditional logistic regression with adjustment for important confounders was used to estimate the OR.

RESULTS

We observed no overall association between occupational UVR exposure and breast cancer. After the age of 50 years, longer duration of UVR exposure (≥20 years: OR=0.83, 95% CI 0.75 to 0.92) and highest cumulative exposure (OR=0.89, 95% CI 0.83 to 0.95) were inversely associated with risk. Our results did not reflect any notable risk difference by oestrogen receptor status.

CONCLUSIONS

This study indicates an inverse association between long-term occupational UVR exposure and late-onset breast cancer. This finding needs further attention in future occupational studies.

CdO/CdCO3 nanocomposite physical properties and cytotoxicity against selected breast cancer cell lines

Cadmium Oxide nanoparticles have the lowest toxicity when compared to nanoparticles of other semiconductors and they are not detrimental to human and mammalian cells, thereby making them candidates for targeting cancer cells. Synadenium cupulare plant extracts were used to synthesize CdO/CdCO3 nanocomposite using cadmium nitrate tetrahydrate 98% as a precursor salt. The resultant nanoparticles were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy, ultraviolet visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The nanoparticles were then screened for effect on breast cancer cell lines (MCF-7 and MDA MB-231) and Vero cell line to determine their growth inhibition effect. Cytotoxicity effect was evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. XRD showed the peaks of monteponite CdO and otavite CdCO3 nanoparticles. TEM results showed irregular and spherical particles of varying sizes, whilst SEM revealed a non-uniform morphology. FTIR results showed peaks of functional groups which are present in some of the phytochemical compounds found in S. cupulare, and point to the presence of CdO. Annealed CdO/CdCO3 NPs showed selectivity for MCF7 and MDA MB231 in comparison to Vero cell line, thereby supporting the hypothesis that cadmium oxide nanoparticles inhibit growth of cancerous cells more than non-cancerous cells.

Evaluation of Vitamin D-Binding Protein Gene Polymorphism and its Plasma Concentration in Kurdish Patients With Breast Cancer in Sanandaj, Iran

Background: Several studies have indicated that polymorphism in vitamin D pathway genes is associated with breast cancer (BC) risk. Vitamin D-binding protein (VDBP) is a vital element in the metabolism of the vitamin D. VDBP carries the serum 25(OH) D3 to cells to promote vitamin D biological functions, such as cell proliferation and apoptosis. Missense SNP (rs.7041) is a common polymorphism in VDBP gene, which shows ethnic-specific allele frequencies. Objectives: This study presents the correlation of the rs7041 (Asp432Glu) gene polymorphism and plasma concentrations of VDBP in Kurdish patients with BC in Sanandaj, Iran. Methods: This cross-sectional study included 44 premenopausal BC patients and 44 healthy subjects. Plasma VDBP concentration was measured by enzyme-linked immunosorbent assay (ELISA). The VDBP (rs7041) was genotyped by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). Results: VDBP level was associated with a non-significant risk of BC (P=0.397). Frequencies of individuals with VDBP (rs7041) TT, TG, and GG genotypes were 13.6%, 52.2%, and 34.09% in case group and 11.3%, 79.5%, and 9.9% in control group, respectively. Genotype GG associated with increased susceptibility to developing BC (odds ratio [OR]=5.172, CI: 1.555-17.2, P=0.007). There was a significant reverse correlation between GT genotype and BC (OR=0.282, 95% CI: 0.110-0.722, P=0.008) Conclusion: The changes in the vitamin D pathway may increase susceptibility to develop BC in the Iranian Kurdish population.

Calcitriol in the Presence of Conditioned Media from Metastatic Breast Cancer Cells Enhances Ex Vivo Polarization of M2 Alternative Murine Bone Marrow-Derived Macrophages

Simple Summary

In this study, we stimulated bone marrow-derived macrophages to M0, M1, and M2 subtypes, with or without calcitriol, or with or without 4T1 (metastatic), 67NR (non-metastatic), and Eph4-Ev (normal) cell culture supernatants (CMs) to test their effect on polarization. We showed that calcitriol increased the expression of Cd206 and Spp1 mRNA and CD36, CCL2, and arginase levels for M2 macrophages and decreased Cd80 and Spp1 mRNA and IL-1, IL-6, OPN, and iNOS for M1 macrophages. 4T1 CM influenced the expression of the studied genes and proteins to a greater extent than 67NR and Eph4; the strongest effect was noted for M2 macrophages. We show that calcitriol and 4T1 CM enhance the polarization of M2 macrophages and M2 macrophages differentiated with calcitriol-stimulated migration of 4T1 and 67NR cells. We indicate that the immunosuppressive properties of calcitriol may unfavorably affect the tumor microenvironment, and supplementation with vitamin D in oncological patients may not always bring benefits.

Abstract

In this study, we differentiated murine bone marrow-derived macrophages (BMDMs) into M0, M1, and M2 in the presence or absence of calcitriol. Real-time PCR analysis of gene expression, FACS analysis of surface markers, and chemokine/cytokine production assays were performed. In addition, the effect of the conditioned media (CM) from murine breast cancer 4T1 (metastatic) and 67NR (non-metastatic) and Eph4-Ev (normal) cells with and without calcitriol on the polarization of M1/M2 cells was determined. We found that calcitriol enhanced the differentiation of M2 macrophages, which was manifested by increased expression of Cd206 and Spp1 mRNA and CD36, Arg, and CCL2 in M2 BMDMs and by decreased expression of Cd80 and Spp1 mRNA and IL-1, IL-6, OPN, and iNOS in M1 BMDMs. 4T1 CM showed a higher effect on the gene and protein expression in macrophages than 67NR and Eph4-Ev, with the greatest effect observed on M2 macrophages which increased their differentiation and properties characteristic of alternative macrophages. Moreover, M2 macrophages differentiated with calcitriol-stimulated migration of 4T1 and 67NR cells through fibronectin and collagen type IV, respectively. Overall, our results indicated that vitamin D supplementation may not always be beneficial, especially in relation to cancers causing excessive, pathological activation of the immune system.

Vitamin D Effects on Cell Differentiation and Stemness in Cancer

Vitamin D₃ is the precursor of 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), a pleiotropic hormone that is a major regulator of the human genome. 1,25(OH)₂D₃ modulates the phenotype and physiology of many cell types by controlling the expression of hundreds of genes in a tissue- and cell-specific fashion. Vitamin D deficiency is common among cancer patients and numerous studies have reported that 1,25(OH)₂D₃ promotes the differentiation of a wide panel of cultured carcinoma cells, frequently associated with a reduction in cell proliferation and survival. A major mechanism of this action is inhibition of the epithelial–mesenchymal transition, which in turn is largely based on antagonism of the Wnt/β-catenin, TGF-β and EGF signaling pathways. In addition, 1,25(OH)₂D₃ controls the gene expression profile and phenotype of cancer-associated fibroblasts (CAFs), which are important players in the tumorigenic process. Moreover, recent data suggest a regulatory role of 1,25(OH)₂D₃ in the biology of normal and cancer stem cells (CSCs). Here, we revise the current knowledge of the molecular and genetic basis of the regulation by 1,25(OH)₂D₃ of the differentiation and stemness of human carcinoma cells, CAFs and CSCs. These effects support a homeostatic non-cytotoxic anticancer action of 1,25(OH)₂D₃ based on reprogramming of the phenotype of several cell types.

Vitamin D Signaling in Inflammation and Cancer: Molecular Mechanisms and Therapeutic Implications

Vitamin D and its active metabolites are important nutrients for human skeletal health. UV irradiation of skin converts 7-dehydrocholesterol into vitamin D3, which metabolized in the liver and kidneys into its active form, 1α,25-dihydroxyvitamin D3. Apart from its classical role in calcium and phosphate regulation, scientists have shown that the vitamin D receptor is expressed in almost all tissues of the body, hence it has numerous biological effects. These includes fetal and adult homeostatic functions in development and differentiation of metabolic, epidermal, endocrine, neurological and immunological systems of the body. Moreover, the expression of vitamin D receptor in the majority of immune cells and the ability of these cells to actively metabolize 25(OH)D3 into its active form 1,25(OH)₂D3 reinforces the important role of vitamin D signaling in maintaining a healthy immune system. In addition, several studies have showed that vitamin D has important regulatory roles of mechanisms controlling proliferation, differentiation and growth. The administration of vitamin D analogues or the active metabolite of vitamin D activates apoptotic pathways, has antiproliferative effects and inhibits angiogenesis. This review aims to provide an up-to-date overview on the effects of vitamin D and its receptor (VDR) in regulating inflammation, different cell death modalities and cancer. It also aims to investigate the possible therapeutic benefits of vitamin D and its analogues as anticancer agents.

Vitamin D in Triple-Negative and BRCA1-Deficient Breast Cancer-Implications for Pathogenesis and Therapy

Several studies show that triple-negative breast cancer (TNBC) patients have the lowest vitamin D concentration among all breast cancer types, suggesting that this vitamin may induce a protective effect against TNBC. This effect of the active metabolite of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D), can be attributed to its potential to modulate proliferation, differentiation, apoptosis, inflammation, angiogenesis, invasion and metastasis and is supported by many in vitro and animal studies, but its exact mechanism is poorly known. In a fraction of TNBCs that harbor mutations that cause the loss of function of the DNA repair-associated breast cancer type 1 susceptibility (BRCA1) gene, 1,25(OH)2D may induce protective effects by activating its receptor and inactivating cathepsin L-mediated degradation of tumor protein P53 binding protein 1 (TP53BP1), preventing deficiency in DNA double-strand break repair and contributing to genome stability. Similar effects can be induced by the interaction of 1,25(OH)2D with proteins of the growth arrest and DNA damage-inducible 45 (GADD45) family. Further studies on TNBC cell lines with exact molecular characteristics and clinical trials with well-defined cases are needed to determine the mechanism of action of vitamin D in TNBC to assess its preventive and therapeutic potential.

Hormone Receptor Expression in Multicentric/Multifocal versus Unifocal Breast Cancer: Especially the VDR Determines the Outcome Related to Focality

The aim of this study was to evaluate the prognostic impact that hormone receptor (HR) expressions have on the two different breast cancer (BC) entities—multifocal versus unifocal BC. As the prognosis determining aspects, we investigated the overall survival (OS) and disease-free survival (DFS) by univariate and multivariate analysis. To underline the study’s conclusions, we additionally considered the histopathological grading and the tumor node metastasis (TNM) staging. A retrospective analysis was performed on survival-related events in a series of 320 breast cancer patients treated at the Department of Gynecology and Obstetrics at the Ludwig Maximillian University in Munich between 2000 and 2002. All three steroid receptors analyzed by immunohistochemistry, namely, the estrogen receptor (ER), the progesterone receptor (PR), and the vitamin D receptor (VDR), showed a significantly positive influence on the course of the disease, but only for the unifocal breast tumor patients. The prognosis of patients with multifocal breast cancer was either not affected by estrogen and/or progesterone receptor expression or even involved a worse etiopathology for the vitamin D receptor-positive patients. The estrogen receptor in unifocal breast cancer and the vitamin D receptor in multifocal breast cancer were especially identified as an independent prognostic marker for overall survival, when adjusted for age, grading, and staging. Altogether, our results strengthen the need to further investigate the behavior of the hormone receptors in breast cancer and understand why they have different effects on each focality type. Moreover, the studies for an adopted vitamin D supplementation due to breast cancer focality type must be enlarged to fully comprehend the remarkable and interesting role played by the vitamin D receptor.

Nutrition in the Prevention of Breast Cancer: A Middle Eastern Perspective

This paper reviews the escalating burden of breast cancer (BC) in the Middle East (ME) and the prevalence of modifiable risk factors and underscores opportunities to promote the prevention of the disease. Similar to more developed countries, BC is the most frequent cancer among women in countries of the ME, accounting for one-third of total cancer cases and 24% of total cancer deaths. Average age at BC diagnosis appears to be a decade earlier in Middle Eastern countries compared to the Western countries, and its incidence is predicted to further increase. Although incidence rates of BC are still lower in Middle Eastern countries than Western ones, mortality rates are similar and at times even higher. It is estimated that 30% of BC cases are due to environmental and lifestyle factors, such as obesity and diet and hence can be preventable. The ME suffers from surging rates of obesity, with eight of its countries ranking among the highest worldwide in obesity prevalence among adults aged 18 and above. ME countries with the highest prevalence of obesity that are among the top 20 worldwide include United Arab Emirates (UAE), Lebanon, Egypt, Libya, Qatar, Saudi Arabia, Jordan, and Kuwait with rates ranging from 30% in UAE to 37% in Kuwait. In parallel, studies in the ME have consistently showed a shift in dietary intake whereby traditional diets, rich in fruits and vegetables, are progressively eroding and being replaced by westernized diets high in energy and fat. Accumulating evidence is reporting convincing association between consumption of such westernized diets and higher BC risk. Addressing these risk factors and studying their association with BC in terms of their nature and magnitude in Middle Eastern countries could provide the basis for intervention strategies to lower the risk and alleviate the burden of BC in these countries.

Randomized window of opportunity trial evaluating high-dose vitamin D in breast cancer patients

PURPOSE

Epidemiologic and preclinical data suggest a potential role for vitamin D in breast cancer treatment and prevention. However, results of prospective randomized trials are inconsistent. The objective of this study was to assess the effects of high-dose cholecalciferol (vitamin D3) on breast tumour proliferation and apoptosis.

METHODS

We conducted a prospective, randomized, phase 2, double-blinded pre-surgical window of opportunity trial. Newly diagnosed breast cancer patients were randomized to receive 40,000 IU of vitamin D3 per day or placebo for 2 to 6 weeks prior to breast surgery. The primary outcome was the relative change in proliferation (Ki67) and apoptosis (cleaved caspase 3 apoptotic assay [CC3]) in primary breast cancer cells pre and post treatment.

RESULTS

Of 83 patients randomized, 80 completed the study (43 (53.8%) vitamin D and 37 (46.3%) placebo). Mean duration of drug intake was 19 days (range 9-28 days). There were no significant differences between the control arm and the vitamin D arm in percent changes of either Ki67 index (1.6% vs. 16.7%, p = 0.25) or CC3 (- 55.9% vs. - 45.9%, p = 0.28). Serum 25-hydroxyvitamin D (25-OHD) levels were 3 times higher in the vitamin D arm (62 nmol/L vs. 246 nmol/L, p < 0.001). Adverse effects were minimal and all classified as grade 1.

CONCLUSIONS

Despite significantly higher levels of serum 25-OHD in the vitamin D-treated group, this was not associated with any significant effects on tumour proliferation or apoptosis. These findings are consistent with the lack of benefit observed in prospective prevention trials.

TRIAL REGISTRY

Trial registration clinicaltrials.gov NCT01948128.

Loss of the Vitamin D Receptor in Human Breast Cancer Cells Promotes Epithelial to Mesenchymal Cell Transition and Skeletal Colonization

Expression of the vitamin D receptor (VDR) is thought to be associated with neoplastic progression. However, the role of the VDR in breast cancer metastasis to bone and the molecular mechanisms underlying this process are unknown. Employing a rodent model (female Balb/c nu/nu mice) of systemic metastasis, we here demonstrate that knockdown of the VDR strongly increases the metastatic potential of MDA-MB-231 human breast cancer cells to bone, resulting in significantly greater skeletal tumor burden. Ablation of VDR expression promotes cancer cell mobility (migration) and invasiveness, thereby facilitating skeletal colonization. Mechanistically, these changes in tumor cell behavior are attributable to shifts in the expression of proteins involved in cell adhesion, proliferation, and cytoskeletal organization, patterns characteristic for epithelial-to-mesenchymal cell transition (EMT). In keeping with these experimental findings, analyses of human breast cancer specimens corroborated the association between VDR expression, EMT-typical changes in protein expression patterns, and clinical prognosis. Loss of the VDR in human breast cancer cells marks a critical point in oncogenesis by inducing EMT, promoting the dissemination of cancer cells, and facilitating the formation of tumor colonies in bone. © 2019 American Society for Bone and Mineral Research.

A Narrative Role of Vitamin D and Its Receptor: With Current Evidence on the Gastric Tissues

Vitamin D is a major steroid hormone that is gaining attention as a therapeutic molecule. Due to the general awareness of its importance for the overall well-being, vitamin D deficiency (VDD) is now recognized as a major health issue. The main reason for VDD is minimal exposure to sunlight. The vitamin D receptor (VDR) is a member of the steroid hormone receptors that induces a cascade of cell signaling to maintain healthy Ca²⁺ levels that serve to regulate several biological functions. However, the roles of vitamin D and its metabolism in maintaining gastric homeostasis have not yet been completely elucidated. Currently, there is a need to increase the vitamin D status in individuals worldwide as it has been shown to improve musculoskeletal health and reduce the risk of chronic illnesses, including some cancers, autoimmune and infectious diseases, type 2 diabetes mellitus, neurocognitive disorders, and general mortality. The role of vitamin D in gastric homeostasis is crucial and unexplored. This review attempts to elucidate the central role of vitamin D in preserving and maintaining the overall health and homeostasis of the stomach tissue.

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 β (IFNβ), 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.

Vitamin D Deficiency: Effects on Oxidative Stress, Epigenetics, Gene Regulation, and Aging

Recent advances in vitamin D research indicate that this vitamin, a secosteroid hormone, has beneficial effects on several body systems other than the musculoskeletal system. Both 25 dihydroxy vitamin D [25(OH)₂D] and its active hormonal form, 1,25-dihydroxyvitamin D [1,25(OH)₂D] are essential for human physiological functions, including damping down inflammation and the excessive intracellular oxidative stresses. Vitamin D is one of the key controllers of systemic inflammation, oxidative stress and mitochondrial respiratory function, and thus, the aging process in humans. In turn, molecular and cellular actions form 1,25(OH)₂D slow down oxidative stress, cell and tissue damage, and the aging process. On the other hand, hypovitaminosis D impairs mitochondrial functions, and enhances oxidative stress and systemic inflammation. The interaction of 1,25(OH)₂D with its intracellular receptors modulates vitamin D–dependent gene transcription and activation of vitamin D-responsive elements, which triggers multiple second messenger systems. Thus, it is not surprising that hypovitaminosis D increases the incidence and severity of several age-related common diseases, such as metabolic disorders that are linked to oxidative stress. These include obesity, insulin resistance, type 2 diabetes, hypertension, pregnancy complications, memory disorders, osteoporosis, autoimmune diseases, certain cancers, and systemic inflammatory diseases. Vitamin D adequacy leads to less oxidative stress and improves mitochondrial and endocrine functions, reducing the risks of disorders, such as autoimmunity, infections, metabolic derangements, and impairment of DNA repair; all of this aids a healthy, graceful aging process. Vitamin D is also a potent anti-oxidant that facilitates balanced mitochondrial activities, preventing oxidative stress-related protein oxidation, lipid peroxidation, and DNA damage. New understandings of vitamin D-related advances in metabolomics, transcriptomics, epigenetics, in relation to its ability to control oxidative stress in conjunction with micronutrients, vitamins, and antioxidants, following normalization of serum 25(OH)D and tissue 1,25(OH)₂D concentrations, likely to promise cost-effective better clinical outcomes in humans.

Nutrition knowledge, attitudes, and practice towards breast cancer prevention among the female population of Iran University of medical science students

Diet plays a measurable role in breast cancer (BC) prevention. The aims of this study were to assess nutrition-related BC prevention Knowledge, attitudes and practice (KAP) of female university students and to examine the relationship between demographic characteristics of students and their KAP. We conducted a cross-sectional study among 500 female students from Iran University of Medical Science (IUMS). A pretested self-administered questionnaires were used to assess the participants' nutrition-related BC prevention KAP. A total of 500 students completed the survey. Students' knowledge with the mean score of 16.97, significantly varied by age (P= 0.03), the field of study (P= 0.001) and family history of BC (P= 0.01). The mean score of attitudes and practice toward nutrition-related BC prevention factors were 24.86 and 39.39, respectively. A significant relationship was observed between nutrition knowledge and attitude (r = 0.27, P < 0.001). Also, Nutrition-related attitudes were positively correlated with the BC prevention dietary practices (r = 0.23, P < 0.001). Nutrition KAP about BC prevention factors was found to be influenced by individual factors such as age, field of study, familial history of BC, job and residency status. Together, our findings confirm that increasing nutrition knowledge is not sufficient for dietary behavior change, but is necessary.

Serum 25-hydroxyvitamin D and mammographic density in premenopausal Spanish women

The role of vitamin D in mammographic density is still unclear. This study examines the association between serum 25-hydroxyvitamin D (25(OH)D) and mammographic density, overall and by specific women characteristics. DDM-Madrid is a cross-sectional study that recruited 1403 premenopausal women in a breast radiodiagnosis unit of Madrid City Council. Information was collected with a questionnaire and plasma 25(OH)D was measured by solid-phase extraction on-line coupled to liquid chromatography-tandem mass spectrometry. Percent mammographic density was assessed using a semi-automated computer tool (DM-Scan). Multivariable linear regression models were used to quantify the associations, categorizing 25(OH)D levels (nmol/L) into 3 groups according to the cut-offs established by the US Endocrine Society. Models were adjusted for age, education, body mass index, age at menarche, parity, previous breast biopsies, family history of breast cancer, physical activity, energy intake, use of corticoids, hypercholesterolemia and day of sample extraction. Mean serum 25(OH)D level was 49.4 + 18.9 nmol/L. Women with sufficient concentrations of 25(OH)D showed a slight decrease in mammographic density (β _>75nmol/L=-3.40; p = 0.037). No differences were observed according to women characteristics except for parity, where the protective effect of 25(OH)D was only seen among nulliparous (β _>75nmol/L=-13.00; p-heterogeneity = 0.006). In light of the protective effect of vitamin D on mammographic density and the high prevalence of vitamin D insufficiency in our population, improving these levels could be an effective measure for the prevention of health problems related to the lack of this essential vitamin.

Vitamin D Status and Association of VDR Genetic Polymorphism to Risk of Breast Cancer in Ethiopia

Emerging evidence associates vitamin D deficiency and vitamin D receptor (VDR) genetic variations with risk for breast cancer. This study investigated the prevalence of vitamin D deficiency and its association with tumor characteristics and the implications of VDR genetic variations for risk of breast cancer in Ethiopia. This unmatched case–control study involved 392 female breast cancer patients and 193 controls. The plasma 25-hydroxyvitamin D (25(OH)D₃) level was quantified in chemotherapy-naïve (N = 112) and tamoxifen-treated patients (N = 89). Genotyping for the VDR common variant alleles rs7975232 (ApaI), rs2228570 (FokI), and rs731236 (TaqI) was done. Eighty-six percent of the patients were vitamin D deficient (<50 nmol/L). Chemotherapy-naïve breast cancer patients had a higher prevalence of vitamin D deficiency (91.9% vs. 78.3%) compared to the tamoxifen-treated group (p < 0.001). The prevalence of severe vitamin D deficiency (<25 nmol/L) was significantly higher in chemotherapy-naïve (41.1%) than tamoxifen-treated (11.2%) patients. Vitamin D deficiency was not significantly associated with tumor characteristics or VDR genotype. The rs2228570 GG genotype was associated with increased risk of breast cancer (OR = 1.44, 95% confidence interval = 1.01−2.06). Our result indicates that rs2228570 might be a moderate risk factor for breast cancer development in the Ethiopian population. The high prevalence of severe vitamin D deficiency in treatment-naïve breast cancer patients indicates the need for nutritional supplementation of vitamin D at the time of chemotherapy initiation.

Vitamin D, Inflammation and Immunity: Review of Literature and Considerations on Recent Translational and Clinical Research Developments

The most relevant and recent literature findings linking exposure to sunlight, Vitamin D (VD), inflammation and immune system in health and disease, are reviewed.

Reduced sunlight exposure determined hypo-vitaminosis D to be common among patients or even healthy subjects, especially at higher latitudes. Numerous studies support the hypothesis that VD insufficiency could contribute to the higher autoimmune diseases incidence in the same geographic areas.

In the present review, the ways in which VD was reported to influence immune system, contributing to organism homeostasis or disease development are addressed. In fact, some of the hormone activities were recognised to determine stimulation or inhibition of immune system components.

Several diseases, where an association with VD deficiency was studied, are summarised. Finally, the rationale for optimization of substitutive/additive therapy with VD analogues and the last innovations regarding these drugs are mentioned.

Vitamin D-induced vitamin D receptor expression induces tamoxifen sensitivity in MCF-7 stem cells via suppression of Wnt/β-catenin signaling

Objective: Cancer stem cells (CSCs) are responsible for the drug resistance of breast cancers. Vitamin D deficiency promotes tumor resistance. The present study examined the effect of vitamin D and vitamin D receptor (VDR) expression on the tamoxifen resistance of CSCs. Methods: MCF-7 cells were treated with 1,25(OH)₂D₃ and their levels of VDR expression, viability, and apoptosis were detected. CD133⁺ MCF-7 stem cells were identified and transfected with a VDR-overexpression plasmid. The tamoxifen concentration that reduced MCF-7 cell viability by 50% (IC₅₀) was determined. The activation of Wnt/β-catenin signaling was also investigated. Results: Vitamin D reduced the viability of MCF-7 cells and promoted their apoptosis. Vitamin D enhanced VDR expression and induced DNA damage. When CD133⁺ stem cells were separated from MCF-7 cells, the IC₅₀ of tamoxifen for stem cells was significantly higher than that of parental MCF-7 cells, suggesting a higher tamoxifen resistance in MCF-7 stem cells. Levels of VDR expression and Wnt/β-catenin signaling in CD133⁺ cells were markedly lower and higher than those in CD133⁻ cells, respectively. Stem cells transfected with VDR overexpression plasmids showed decreased tamoxifen IC₅₀ values, viability, spheroid formation, and expression of Wnt and β-catenin proteins when compared with control cells. Cell apoptosis was increased by transfection with a VDR overexpression plasmid. Finally, the inhibitory effects induced by VDR overexpression could be reversed by the VDR inhibitor, calcifediol. Conclusion: Stem cells contributed to the tamoxifen resistance of MCF-7 cells. Vitamin D-induced VDR expression increased the sensitivity of MCF-7 stem cells to tamoxifen by inhibiting Wnt/β-catenin signaling.

Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort

Background

While numerous epidemiologic studies have found an association between higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and lower breast cancer risk, few have assessed this association for concentrations >40 ng/ml.

Objective

To investigate the relationship between 25(OH)D concentration and breast cancer risk across a broad range of 25(OH)D concentrations among women aged 55 years and older.

Methods

Analyses used pooled data from two randomized clinical trials (N = 1129, N = 2196) and a prospective cohort (N = 1713) to examine a broad range of 25(OH)D concentrations. The outcome was diagnosis of breast cancer during the observation periods (median: 4.0 years). Three analyses were conducted: 1) Incidence rates were compared according to 25(OH)D concentration from <20 to ≥60 ng/ml (<50 to ≥150 nmol/L), 2) Kaplan-Meier plots were developed and 3) multivariate Cox regression was used to examine the association between 25(OH)D and breast cancer risk using multiple 25(OH)D measurements.

Results

Within the pooled cohort (N = 5038), 77 women were diagnosed with breast cancer (age-adjusted incidence: 512 cases per 100,000 person-years). Results were similar for the three analyses. First, comparing incidence rates, there was an 82% lower incidence rate of breast cancer for women with 25(OH)D concentrations ≥60 vs <20 ng/ml (Rate Ratio = 0.18, P = 0.006). Second, Kaplan-Meier curves for concentrations of <20, 20–39, 40–59 and ≥60 ng/ml were significantly different (P = 0.02), with the highest proportion breast cancer-free in the ≥60 ng/ml group (99.3%) and the lowest proportion breast cancer-free in the <20 ng/ml group (96.8%). The proportion with breast cancer was 78% lower for ≥60 vs <20 ng/ml (P = 0.02). Third, multivariate Cox regression revealed that women with 25(OH)D concentrations ≥60 ng/ml had an 80% lower risk of breast cancer than women with concentrations <20 ng/ml (HR = 0.20, P = 0.03), adjusting for age, BMI, smoking status, calcium supplement intake, and study of origin.

Conclusions

Higher 25(OH)D concentrations were associated with a dose-response decrease in breast cancer risk with concentrations ≥60 ng/ml being most protective.

Vitamin D and breast cancer: Past and present

The presence of the vitamin D receptor in mammary gland and breast cancer has been recognized since the early 1980s, and multiple pre-clinical studies have demonstrated that its ligand 1,25D modulates normal mammary gland development and sensitivity to carcinogenesis. Although studies have characterized many 1,25D responsive targets in normal mammary cells and in breast cancers, validation of relevant targets that regulate cell cycle, apoptosis, autophagy and differentiation, particularly in vivo, has been challenging. Vitamin D deficiency is common in breast cancer patients and some evidence suggests that low vitamin D status enhances the risk for disease development or progression. Model systems of carcinogenesis have provided evidence that both VDR expression and 1,25D actions change with transformation but clinical data regarding vitamin D responsiveness of established tumors is limited and inconclusive. Because breast cancer is heterogeneous, analysis of VDR actions in specific molecular subtypes of the disease is necessary to clarify the conflicting data. Genomic, proteomic and metabolomic analyses of in vitro and in vivo model systems is also warranted to comprehensively understand the network of vitamin D regulated pathways in the context of breast cancer heterogeneity.

Examination of VDR/RXR/DRIP205 Interaction, Intranuclear Localization, and DNA Binding in Ras-Transformed Keratinocytes and Its Implication for Designing Optimal Vitamin D Therapy in Cancer

Retinoid X receptor (RXR) occupies a central position within the nuclear receptor superfamily, serving as an obligatory partner to numerous other nuclear receptors, including vitamin D receptor (VDR). In the current study, we examined whether phosphorylation of RXRα at serine 260 affects VDR/RXR and VDR interacting protein (DRIP) 205 coactivator recruitment, interactions, and binding of the VDR/human RXRα (hRXRα)/DRIP205 complex to chromatin. Serine 260 is a critical amino acid on the hRXRα that is located in close spatial proximity to regions of coactivator and corepressor interactions. Using fluorescence resonance energy transfer and immunofluorescence studies, we showed that the physical interaction between hRXRα and DRIP205 coactivator was impaired in human keratinocytes with the ras oncogene (HPK1Aras) or transfected with the wild-type hRXRα. Furthermore, the nuclear colocalization of VDR/DRIP205, hRXRα/DRIP205, and VDR/hRXRα/DRIP205 complex binding to chromatin is impaired in the HPK1Aras cells when compared with the normal human keratinocytes (HPK1A cells). However, transfection with the nonphosphorylatable hRXRα (S260A) mutant or treatment with the mitogen-activated protein kinase (MAPK) inhibitor UO126 rescued their nuclear localization, interaction, and binding of the complex to chromatin in the HPK1Aras cells. In summary, we have demonstrated, using highly specific intracellular tagging methods in live and fixed cells, important alterations of the vitamin D signaling system in cancer cells in which the ras-raf-MAPK system is activated, suggesting that specific inhibition of this commonly activated pathway could be targeted therapeutically to enhance vitamin D efficacy.

Identification of tumor-autonomous and indirect effects of vitamin D action that inhibit breast cancer growth and tumor progression

Several epidemiological studies have found that low vitamin D levels are associated with worse prognosis and poorer outcomes in patients with breast cancer (BCa), although some studies have failed to find this association. In addition, prior research has found that BCa patients with vitamin D deficiency have a more aggressive molecular phenotype and worse prognostic biomarkers. As vitamin D deficiency is common in patients diagnosed with BCa, elucidating the cause of the association between poor outcomes and vitamin D deficiency promises to have a significant impact on improving care for patients with BCa including enabling the development of novel therapeutic approaches. Here we review our recent findings in this area, including our data revealing that reduction of the expression of the vitamin D receptor (Vdr) within BCa cells accelerates primary tumor growth and enables the development of metastases, demonstrating a tumor autonomous effect of vitamin D signaling to suppress BCa metastases. We believe that these findings are likely relevant to humans as we discovered evidence that a mechanism of VDR regulation identified in our mouse models is conserved in human BCa. In particular, we identified a negative correlation between serum 25(OH)D concentration and the level of expression of the tumor progression factor ID1 in primary tumors from patients with breast cancer.

High Altitude and Cancer Mortality

Thiersch, Markus, and Erik R. Swenson. High altitude and cancer mortality. High Alt Med Biol 19:116-123, 2018.-Humans living at high altitude (HA) are exposed to chronic (hypobaric) hypoxia. Despite the permanent stress of hypoxic exposure, humans populating HA areas have reduced cancer mortality over a broad spectrum of cancer types. In fact, the majority of the physiological adaptive processes at HA occurring in response to hypoxia might be the driving force for reduced cancer mortality at HA. In this review, we summarize epidemiological and animal studies that compare cancer incidence and cancer mortality between HA and low altitude or between hypoxia and normoxia, respectively. We discuss the potential role of oxygen-independent and oxygen-dependent mechanisms that might contribute to reduced cancer mortality at HA. Reactive oxygen species and their detoxification as well as the hypoxia-inducible factors are especially promising targets and may be related to why cancer mortality is reduced at HA. In addition, we briefly discuss two aspects with a proven impact on tumorigenesis, namely the immune system and tumor surveillance as well as HA-induced metabolic changes. Further animal and clinical studies are clearly needed to explain why cancer mortality is reduced at HA and to decide whether HA or hypoxia-based therapeutic approaches could be implemented for cancer treatment. However, exposure to HA activates multiple adaptive mechanisms (oxygen independent and oxygen dependent) sharing common pathways as well as activating counteracting pathways, which complicate the identification of specific HA-induced mechanisms of tumor suppression.

Calcitriol Supplementation Causes Decreases in Tumorigenic Proteins and Different Proteomic and Metabolomic Signatures in Right versus Left-Sided Colon Cancer

Vitamin D deficiency is a common problem worldwide. In particular, it is an issue in the Northern Hemisphere where UVB radiation does not penetrate the atmosphere as readily. There is a correlation between vitamin D deficiency and colorectal cancer incidence and mortality. Furthermore, there is strong evidence that cancer of the ascending (right side) colon is different from cancer of the descending (left side) colon in terms of prognosis, tumor differentiation, and polyp type, as well as at the molecular level. Right-side tumors have elevated Wnt signaling and are more likely to relapse, whereas left-side tumors have reduced expression of tumor suppressor genes. This study seeks to understand both the proteomic and metabolomic changes resulting from treatment of the active metabolite of vitamin D, calcitriol, in right-sided and left-sided colon cancer. Our results show that left-sided colon cancer treated with calcitriol has a substantially greater number of changes in both the proteome and the metabolome than right-sided colon cancer. We found that calcitriol treatment in both right-sided and left-sided colon cancer causes a downregulation of ribosomal protein L37 and protein S100A10. Both of these proteins are heavily involved in tumorigenesis, suggesting a possible mechanism for the correlation between low vitamin D levels and colon cancer.

Nuclear receptor gene polymorphisms and warfarin dose requirements in the Quebec Warfarin Cohort

Warfarin is primarily metabolized by cytochrome 2C9, encoded by gene CYP2C9. Here, we investigated whether variants in nuclear receptor genes which regulate the expression of CYP2C9 are associated with warfarin response. We used data from 906 warfarin users from the Quebec Warfarin Cohort (QWC) and tested the association of warfarin dose requirement at 3 months following the initiation of therapy in nine nuclear receptor genes: NR1I3, NR1I2, NR3C1, ESR1, GATA4, RXRA, VDR, CEBPA, and HNF4A. Three correlated SNPs in the VDR gene (rs4760658, rs11168292, and rs11168293) were associated with dose requirements of warfarin (P = 2.68 × 10^-5, P = 5.81 × 10^-4, and P = 5.94 × 10^-4, respectively). Required doses of warfarin were the highest for homozygotes of the minor allele at the VDR variants (P < 0.0026). Variants in the VDR gene were associated with the variability in response to warfarin, emphasizing the possible clinical relevance of nuclear receptor gene variants on the inter-individual variability in drug metabolism.

Vitamin D Receptor Signaling and Cancer

The vitamin D receptor (VDR) binds the secosteroid hormone 1,25(OH)₂D₃ with high affinity and regulates gene programs that control a serum calcium levels, as well as cell proliferation and differentiation. A significant focus has been to exploit the VDR in cancer settings. Although preclinical studies have been strongly encouraging, to date clinical trials have delivered equivocal findings that have paused the clinical translation of these compounds. However, it is entirely possible that mining of genomic data will help to refine precisely what are the key anticancer actions of vitamin D compounds and where these can be used most effectively.

Vitamin D deficiency is associated with poor breast cancer prognostic features in postmenopausal women

This study aimed to evaluate the association between pretreatment vitamin D (VD) deficiency with breast cancer prognostic features in Brazilian postmenopausal women. An analytical cross sectional study was conducted with 192 women, aged 45-75 years, attended at University Hospital. Women with recent diagnosis of breast cancer, in amenorrhea >12months and age ≥45 years, without medication use or clinical conditions that interfere with VD values were included. Clinical and anthropometric data were collected. Serum level of 25 hydroxyvitamin D [25(OH)D] was measured in all patients until 20days after breast cancer diagnosis, and was classified as normal (≥30ng/mL), insufficiency (20-29ng/mL) and deficiency (<20ng/mL). Data on breast cancer (histopathological type, grade, tumor stage, lymph node status), hormone status (estrogen receptor, ER, progesterone receptor, PR), human epidermal growth factor receptor type 2 (HER2) and epithelial proliferative activity (Ki-67) were collected. For statistical analysis, the t-student test, the Gamma Distribution (asymmetric variables), the chi-square test and the logistic regression (OR-odds ratio) were used. The median 25(OH)D level was 25.8ng/mL (range 12.0-59.2ng/mL). Sufficient vitamin D levels were detected in 65 patients (33.9%), whereas insufficient levels in 92 patients (47.9%), and deficient levels in 35 patients (18.2%). Participants with insufficient and deficient 25(OH)D levels had a higher proportion of tumors with a high grade and locally advanced and metastatic disease, more positive lymph node, a lower proportion of ER, PR positives tumors and higher Ki-67(p<0.05). Patients with normal vitamin D had a higher frequency of luminal A (47.7%) and luminal B (32.2%) tumors when compared to patients with vitamin D insufficiency or deficiency. Furthermore, all cases of triple negative were detected in women with low VD levels. Multivariate analysis, after adjusting for age, time since menopause and BMI, showed that insufficient and deficient level of vitamin D were significantly associated with negative estrogen receptor (OR 3.77 CI 95% 1.76-8.09 and OR 3.99 CI 95% 1.83-8.68), high Ki-67 (OR 2.50, CI 95% 1.35-4.63, and OR 2.62, CI 95% 1.40-4.98), and positive axillary lymph node status (OR 1.59, CI 95% 1.03-2.33, and OR 1.58, CI 95% 1.02-2.92) respectively. In Brazilian postmenopausal women with breast cancer, there was an association between vitamin D insufficiency or deficiency and tumors with worse prognostic features. Low vitamin D levels were shown to be a risk factor for ER negative tumors, with positive axilla and a higher rate of cell proliferation.

Adiposity, breast density, and breast cancer risk: epidemiological and biological considerations

Excess total body fat and abdominal adipose tissue are recognized risk factors for metabolic diseases but also for some types of cancers, including breast cancer. Several biological mechanisms in connection with local and systemic effects of adiposity are believed to be implicated in breast cancer development, and may involve breast fat. Breast adipose tissue can be studied through mammography by looking at breast density features such as the nondense area mainly composed of fat, or the percent breast density, which is the proportion of fibroglandular tissue in relation to fat. The relation between adiposity, breast density features, and breast cancer is complex. Studies suggest a paradoxical association as adiposity and absolute nondense area correlate positively with each other, but in contrast to adiposity, absolute nondense area seems to be associated negatively with breast cancer risk. As breast density is one of the strongest risk factors for breast cancer, it is therefore critical to understand how these factors interrelate. In this review, we discuss these relations by first presenting how adiposity measurements and breast density features are linked to breast cancer risk. Then, we used a systematic approach to capture the literature to review the relation between adiposity and breast density features. Finally, the role of adipose tissue in carcinogenesis is discussed briefly from a biological perspective.

Function of the vitamin D endocrine system in mammary gland and breast cancer

The nuclear receptor for 1α,25-dihydroxycholecalciferol (1,25D), the active form of vitamin D, has anti-tumor actions in many tissues. The vitamin D receptor (VDR) is expressed in normal mammary gland and in many human breast cancers suggesting it may represent an important tumor suppressor gene in this tissue. When activated by 1,25D, VDR modulates multiple cellular pathways including those related to energy metabolism, terminal differentiation and inflammation. There is compelling pre-clinical evidence that alterations in vitamin D status affect breast cancer development and progression, while clinical and epidemiological data are suggestive but not entirely consistent. The demonstration that breast cells express CYP27B1 (which converts the precursor vitamin D metabolite 25D to the active metabolite 1,25D) and CYP24A1 (which degrades both 25D and 1,25D) provides insight into the difficulties inherent in using dietary vitamin D, sun exposure and/or serum biomarkers of vitamin D status to predict disease outcomes. Emerging evidence suggests that the normally tight balance between CYP27B1 and CYP24A1 becomes deregulated during cancer development, leading to abrogation of the tumor suppressive effects triggered by VDR. Research aimed at understanding the mechanisms that govern uptake, storage, metabolism and actions of vitamin D steroids in normal and neoplastic breast tissue remain an urgent priority.

Bioinformatic approaches to interrogating vitamin D receptor signaling

Bioinformatics applies unbiased approaches to develop statistically-robust insight into health and disease. At the global, or "20,000 foot" view bioinformatic analyses of vitamin D receptor (NR1I1/VDR) signaling can measure where the VDR gene or protein exerts a genome-wide significant impact on biology; VDR is significantly implicated in bone biology and immune systems, but not in cancer. With a more VDR-centric, or "2000 foot" view, bioinformatic approaches can interrogate events downstream of VDR activity. Integrative approaches can combine VDR ChIP-Seq in cell systems where significant volumes of publically available data are available. For example, VDR ChIP-Seq studies can be combined with genome-wide association studies to reveal significant associations to immune phenotypes. Similarly, VDR ChIP-Seq can be combined with data from Cancer Genome Atlas (TCGA) to infer the impact of VDR target genes in cancer progression. Therefore, bioinformatic approaches can reveal what aspects of VDR downstream networks are significantly related to disease or phenotype.

Vitamin D receptor polymorphisms or serum levels as key drivers of breast cancer development? The question of the vitamin D pathway

As total vitamin D levels are often lower in black than in white Americans, the former are frequently classified as vitamin D-deficient. To fully understand African vitamin D (25(OH)D) status, other factors should be considered, e.g. vitamin D blood carrier, vitamin D-binding protein (DBP), vitamin D receptor (VDR) and DBP polymorphisms. A prospective study on an indigenous black Tanzanian and a Caucasian Italian population was performed on 50 healthy donors from both populations and 35 Caucasian and 18 African breast cancer patients. 25(OH)D and DBP serum levels were analyzed by ELISA. A1012G, Cdx2 and Fok1 VDR polymorphisms and DBP polymorphisms rs4588 and rs7041 were genotyped by real-time PCR. Vitamin D and DBP levels were lower in healthy African donors than in Caucasians. Africans had a significantly higher frequency of AA and CC for Cdx2 and Fok1 polymorphisms, respectively. These allelic variants were related to a higher transcription of VDR gene and a higher activity of VDR receptor. With regard to polymorphism distribution, Africans showed innate higher levels and activity of VDR. We conclude that a strengthening of the vitamin D pathway could have a protective role against the development of breast cancer in the African population.

Extraskeletal actions of vitamin D

The vitamin D receptor (VDR) is found in nearly all, if not all, cells in the body. The enzyme that produces the active metabolite of vitamin D and ligand for VDR, namely CYP27B1, likewise is widely expressed in many cells of the body. These observations indicate that the role of vitamin D is not limited to regulation of bone and mineral homeostasis, as important as that is. Rather, the study of its extraskeletal actions has become the major driving force behind the significant increase in research articles on vitamin D published over the past several decades. A great deal of information has accumulated from cell culture studies, in vivo animal studies, and clinical association studies that confirms that extraskeletal effects of vitamin D are truly widespread and substantial. However, randomized, placebo-controlled clinical trials, when done, have by and large not produced the benefits anticipated by the in vitro cell culture and in vivo animal studies. In this review, I will examine the role of vitamin D signaling in a number of extraskeletal tissues and assess the success of translating these findings into treatments of human diseases affecting those extracellular tissues.

Circulating 25-Hydroxy Vitamin D Relative to Vitamin D Receptor Polymorphism after Vitamin D3 Supplementation in Breast Cancer Women: A Randomized, Double-Blind Controlled Clinical Trial

Objective: The influence of vitamin D receptor (VDR) genetic variation on serum 25-hydroxyvitamin D levels [25(OH)D] after vitamin D3 supplementation remains unclear. We aimed to investigate changes of 25(OH)D in a randomized, double-blind, placebo-controlled clinical trial, according to VDR genotype, after provision of vitamin D3 to breast cancer cases for a 2-month period. Methods: Participants were assigned to two treatment arms: placebo (n = 28) and vitamin D3 supplementation (n =28). The supplementation group received 50,000 IU of vitamin D every week for 2 months. Blood samples were collected at baseline and after intervention to measure serum 25(OH)D3. Genotypes were assessed for FokI, BsmI, ApaI, and TaqI polymorphisms. Results: After eight weeks supplementation, the intervention group showed a significant increase in the serum concentration of 25 (OH)D3 (28±2.6 to 39±3.5; p=0.004). Subjects were then classified into twelve subgroups according to different VDR genotypes. Subjects with ff/Ff, TT/Tt, and Bb genotypes had significantly higher increases in serum 25(OH)D compared to those with FF, tt, and BB/bb genotypes post-intervention. Serum vitamin D3 levels with the AA genotype were lower than with aa/ Aa. No differences were found among other subgroups. Conclusion: Vitamin D3 supplementation increases serum 25(OH)D in women with breast cancer. Serum vitamin D3 in TT/Tt, ff/Ff, and Bb carriers was more responsive to vitamin D supplementation than in those with FF/ff and tt genotypes. Other subgroups might gain less from vitamin D3 supplementation.

Fluorescence Analysis of Vitamin D Receptor Status of Circulating Tumor Cells (CTCS) in Breast Cancer: From Cell Models to Metastatic Patients

The Vitamin D receptor (VDR) expressed in normal breast tissue and breast tumors has been suggested as a new prognostic biomarker in breast cancer (BC). Besides, increasing evidence supports the view that the detection of circulating tumor cells (CTCs) predicts outcome in early and metastatic BC. Consequently, an evaluation of VDR expression in the CTCs of BC patients may allow optimization of their treatment. As an attempt to profile and subtype the CTCs of metastatic patients, we established an innovative fluorescence technique using nine BC cell lines to visualize, define, and compare their individual VDR status. Afterwards, we tested the CTC presence and VDR expression in blood samples (cytospins) collected from 23 metastatic BC patients. The results demonstrated major differences in the VDR levels among the nine cell lines, and VDR positive CTCs were detected in 46% of CTC-positive patients, with a total of 42 CTCs individually analyzed. Due to the limited number of patients in this study, no correlation between VDR expression and BC subtype classification (according to estrogen receptor (ER), progesterone receptor (PR) and HER2) could be determined, but our data support the view that VDR evaluation is a potential new prognostic biomarker to help in the optimization of therapy management for BC patients.