Anti-proliferative action of vitamin D in MCF7 is still active after siRNA-VDR knock-down

Advances in biomedical applications of vitamin D for VDR targeted management of obesity and cancer

BACKGROUND

1,25(OH)2D3 is a fat-soluble vitamin, involved in regulating Ca2+ homeostasis in the body. Its storage in adipose tissue depends on the fat content of the body. Obesity is the result of abnormal lipid deposition due to the prolonged positive energy balance and increases the risk of several cancer types. Furthermore, it has been associated with vitamin D deficiency and defined as a low 25(OH)2D3 blood level. In addition, 1,25(OH)2D3 plays vital roles in Ca2+-Pi and glucose metabolism in the adipocytes of obese individuals and regulates the expressions of adipogenesis-associated genes in mature adipocytes.

SCOPE AND APPROACH

The present contribution focused on the VDR mediated mechanisms interconnecting the obese condition and cancer proliferation due to 1,25(OH)2D3-deficiency in humans. This contribution also summarizes the identification and development of molecular targets for VDR-targeted drug discovery.

KEY FINDINGS AND CONCLUSIONS

Several studies have revealed that cancer development in a background of 1,25(OH)2D3 deficient obesity involves the VDR gene. Moreover, 1,25(OH)2D3 is also known to influence several cellular processes, including differentiation, proliferation, and adhesion. The multifaceted physiology of obesity has improved our understanding of the cancer therapeutic targets. However, currently available anti-cancer drugs are notorious for their side effects, which have raised safety issues. Thus, there is interest in developing 1,25(OH)2D3-based therapies without any side effects.

Brk/PTK6 and Involucrin Expression May Predict Breast Cancer Cell Responses to Vitamin D3

The process of human embryonic mammary development gives rise to the structures in which mammary cells share a developmental lineage with skin epithelial cells such as keratinocytes. As some breast carcinomas have previously been shown to express high levels of involucrin, a marker of keratinocyte differentiation, we hypothesised that some breast tumours may de-differentiate to a keratinocyte-derived 'evolutionary history'. To confirm our hypothesis, we investigated the frequency of involucrin expression along with that of Brk, a tyrosine kinase expressed in up to 86% of breast carcinomas whose normal expression patterns are restricted to differentiating epithelial cells, most notably those in the skin (keratinocytes) and the gastrointestinal tract. We found that involucrin, a keratinocyte differentiation marker, was expressed in a high proportion (78%) of breast carcinoma samples and cell lines. Interestingly, tumour samples found to express high levels of involucrin were also shown to express Brk. 1,25-dihydroxyvitamin D3, a known differentiation agent and potential anti-cancer agent, decreased proliferation in the breast cancer cell lines that expressed both involucrin and Brk, whereas the Brk/involucrin negative cell lines tested were less susceptible. In addition, responses to 1,25-dihydroxyvitamin D3 were not correlated with vitamin D receptor expression. These data contribute to the growing body of evidence suggesting that cellular responses to 1,25-dihydroxyvitamin D3 are potentially independent of vitamin D receptor status and provide an insight into potential markers, such as Brk and/or involucrin that could predict therapeutic responses to 1,25-dihydroxyvitamin D3.

The Four Horsemen of the Apocalypse: Cancer, Depression, Vitamin D Deficiency, and Obesity: An Observational Study

Objective

Studies aiming at illuminating the complex relationships between cancer, obesity, 25-hydroxy vitamin D (25-OHD) deficiency, and body fat percentage are ongoing. The objective of this study was to investigate the relationships between 25-OHD deficiency, visceral fat tissue, and the Beck Depression Inventory (BDI) in cancer patients.

Methods

This study was conducted from 2013 to 2022. Patients' demographic data, such as age, sex, and body mass index (BMI), and laboratory parameters, including prealbumin, albumin, calcium, phosphorus, parathyroid hormone, 25-OHD, magnesium, hemoglobin, fat percentage, and C-reactive protein, were recorded. The Beck Depression Inventory was used to determine depression levels.

Results

A total of 223 colon cancer patients aged 19-84 undergoing chemotherapy at our clinic were included in this prospective study. The male patients' mean BMI was 22.91 ± 3.74 kg/m², whereas that of the female patients was 26.17 ± 3.75 kg/m². The difference was statistically significant (p < 0.001). The mean total Beck Depression Inventory score was 13 ± 9. In this patient population, 105 (47.09%) patients had minimal depression, 69 (30.94%) had mild depression, 35 (15.70%) had moderate depression, and 14 (6.28%) had severe depression. The Beck Depression Inventory score was negatively and strongly associated with BMI and moderately and negatively associated with albumin levels.

Conclusion

This study reveals a significant correlation between 25-OHD levels and the Beck Depression Inventory scores among cancer patients. We believe that 25-OHD levels may be used to determine the presence of depressive symptoms in cancer patients. However, further comprehensive multicentre studies are needed to draw more definitive conclusions.

Differential effects of the 1,25D3-MARRS receptor (ERp57/PDIA3) on murine mammary gland development depend on the vitamin D3 dose

1,25 dihydroxyvitamin D3 (1,25D3) is the most potent biologically active form of vitamin D3. Its actions on the mammary gland include cell growth inhibition and anti-cancer effects. This study's purpose was to explore the role of the 1,25D3-membrane associated rapid response steroid (MARRS) receptor in the mammary gland using a tissue-specific knockout mouse model and a vitamin D3 dietary intervention. Three genotype groups were created using the Cre/loxp system to knock-down (+/-) and knockout (-/-) the MARRS receptor in epithelial cells of mammary glands (MG). Abdominal MGs were collected from 6-week old female mice (n = 94) on diets of 10,000 IU/kg (excess), 1,000 IU/kg (sufficient) or 0 IU/kg (deficient) of D3. There was a significant interaction between genotype and diet regarding number of terminal end buds (TEBs) (p = 0.001) and ductal coverage of the fat pad (p = 0.03). MARRS -/- mice on the sufficient diet had significantly fewer TEBs (p = 0.001) compared to MARRS +/+ on the same diet, but the opposite effect was seen in mice on the excess diet. There were no effects of genotype on TEBs when animals were vitamin D3 deficient. These results suggest that there is an effect of MARRS on mammary gland development that is dependent on 25(OH)D status, specifically, altering the number of highly proliferative TEBs. Increased numbers of TEBs have been correlated with increased breast cancer risk later in life. Therefore the results of this study warrant further examination of 25(OH)D status and recommendations in adolescent humans to reduce dietary effects on future breast cancer risk.

IL-6 Impairs the Activity of Vitamin D3 in the Regulation of Epithelial-Mesenchymal Transition in Triple Negative Breast Cancer

Objective:

The present study aimed to investigate the possible role of IL-6 and 1α,25-dihydroxyvitamin D3 (1,25D) signaling in epithelial-mesenchymal transition (EMT) and stemness in triple-negative breast cancer (TNBC) cell line.

Methods:

TNBC cell line, HCC 1806, was treated with IL-6 and 1,25D for three and six days. Also, the role of vitamin D receptor (VDR) was studied by transfection of TNBC cell line with VDR gene and transfection efficiency was assessed using Human VDR enzyme-linked immunosorbent assay (ELISA). Changes in E-cadherin gene expression were analyzed by quantitative real-time PCR (qRT-PCR). Also, changes in CD44+ cells were analyzed by flow cytometry. Finally, morphological changes were investigated by light microscopy after 6 days.

Results:

Treatment of HCC1806 cells with IL-6 has no significant effect either on E-cadherin gene expression or CD44+ cells, (p > 0.05). However, E-cadherin gene expression was significantly up-regulated after treatment with 1,25D for 6 days, (p < 0.05). Also, CD44+ cells were significantly reduced after treatment with 1,25D either for 3 or 6 days, (p < 0.05). Transfection of TNBC cell line with VDR gene significantly up-regulated VDR protein expression, (p < 0.05). In addition, overexpression of VDR in TNBC cells and treatment with 1,25D significantly up-regulated E-cadherin gene expression, (p < 0.05) and reduced CD44+ cells, (p < 0.05). Moreover, transfection with VDR and treatment with a combination of 1,25D and IL-6 significantly down-regulated E-cadherin gene expression and increased CD44+ cells compared with transfected cells with VDR treated with 1,25D alone, (p < 0.05). No significant morphological changes were observed in treated cells, 6 days post-treatment.

Conclusion:

The presence of IL-6 in the breast tumor microenvironment may impair the activity of vitamin D3 signaling, limiting its anti-tumor effects in TNBC.

24R,25-Dihydroxyvitamin D3 regulates breast cancer cells in vitro and in vivo

BACKGROUND

Epidemiological studies indicate high serum 25(OH)D₃ is associated with increased survival in breast cancer patients. Pre-clinical studies attributed this to anti-tumorigenic properties of its metabolite 1α,25(OH)₂D₃. However, 1α,25(OH)₂D₃ is highly calcemic and thus has a narrow therapeutic window. Here we propose another metabolite, 24R,25(OH)₂D₃, as an alternative non-calcemic vitamin D₃ supplement.

METHODS

NOD-SCID-IL2γR null female mice with MCF7 breast cancer xenografts in the mammary fat pad were treated with 24R,25(OH)₂D₃ and changes in tumor burden and metastases were assessed. ERα66+ MCF7 and T47D cells, and ERα66- HCC38 cells were treated with 24R,25(OH)₂D₃in vitro to assess effects on proliferation and apoptosis. Effects on migration and metastatic markers were assessed in MCF7.

RESULTS

24R,25(OH)₂D₃ reduced MCF7 tumor growth and metastasis in vivo. In vitro results indicate that this was not due to an anti-proliferative effect; 24R,25(OH)₂D₃ stimulated DNA synthesis in MCF7 and T47D. In contrast, markers of invasion and metastasis were decreased. 24R,25(OH)₂D₃ caused dose-dependent increases in apoptosis in MCF7 and T47D, but not HCC38 cells. Inhibitors to palmitoylation, caveolae integrity, phospholipase-D, and estrogen receptors (ER) demonstrate that 24R,25(OH)₂D₃ acts on MCF7 cells through caveolae-associated, phospholipase D-dependent mechanisms via cross-talk with ERs.

CONCLUSION

These results indicate that 24R,25(OH)₂D₃ shows promise in treatment of breast cancer by stimulating tumor apoptosis and reducing metastasis.

GENERAL SIGNIFICANCE

24R,25(OH)₂D₃ regulates breast cancer cell survival through ER-associated mechanisms similar to 24R,25(OH)₂D₃ effects on chondrocytes. Thus, 24R,25(OH)₂D₃ may modulate cell survival in other estrogen-responsive cell types, and its therapeutic potential should be investigated in ER-associated pathologies.

Role of the ERp57 protein (1,25D3-MARRS receptor) in murine mammary gland growth and development

The protein disulfide isomerase ERp57 (GRp58/PDIA3/1,25D3-MARRS) has been implicated in a multitude of signaling pathways throughout the entire body. Most thoroughly studied for its protein-folding role, ERp57 has also been found to have multiple binding partners, and have significant effects on cellular growth. ERp57 has been studied n the context of several neurodegenerative disorders, metabolic conditions, and can be used as a prognosis marker in certain cancers. One role, as an alternate vitamin D binding receptor, has prompted research in tissues with known vitamin D activity, such as the intestine and bone. Vitamin D has been studied in relation to mammary gland growth and development, but it is not yet known if ERp57 plays an independent role in this tissue. In this study, ERp57 was knocked out in murine mammary gland epithelial cells of 30 4-week old mice. Several markers of mammary gland growth were measured, including number of terminal end buds (TEB), ductal coverage of the fat pad, and ductal extension. It was found the knockout animals had decreased numbers of TEBs (p = 0.019), and decreased ductal extension (p = 0.018) compared to wildtype animals, with no differences in gross body weight. Immunohistochemistry analysis of mammary glands showed ERp57 localized to the apical side of alveolar branches, and on leading edges of TEBs. These results provide further evidence for ERp57 functioning separately to the VDR, and further insights into the roles of ERp57.

A novel glutathione-triggered theranostic prodrug for anticancer and imaging in living cells

A novel theranostic prodrug was designed and synthesized by conjugating a naphthalimide derivative with vitamin D2 via a disulfide linker. The prodrug featured a highly selective detection process for glutathione (GSH) and showed a red-shifted fluorescence within 30 min. Notably, it also exhibited antitumor activity similar to vitamin D2 and could be monitored by cellular imaging.

Design and Synthesis of Novel Vitamin D–Coumarin Hybrids using Microwave Irradiation

A series of novel vitamin D–coumarin hybrids were synthesised by esterification of the corresponding coumarin-3-carboxylic acids and vitamin D or vitamin D CD-ring alcohol in CH2Cl2 under microwave irradiation. They were obtained in higher yields (from 64–81% up to 79–87%) and shorter reaction time (from 3 h down to 15 min), compared with earlier conventional methodologies. The structures of all the target compounds were confirmed by 1H NMR, 13C NMR and HRMS. This provides an attractive and alternative method for the preparation of high-value vitamin D–coumarin hybrids.

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.

Association of Vitamin D3 Level with Breast Cancer Risk and Prognosis in African-American and Hispanic Women

Background: This study investigated the association of vitamin D3 levels with breast cancer risk and progression in African-Americans and Hispanics. Methods: A total of 237 African-American (Cases = 119, Control = 118) and 423 Hispanic women (Cases = 124, Control = 299) were recruited in the study. Blood samples were collected at the time of breast cancer screening and prior to cancer treatment for 4 weeks on average for the cases. The serum 25-hydroxyvitamin D (25(OH)D3) was measured at a Quest-Diagnostics facility. Results: The results showed that 69.2% of African-Americans and 37.8% of Hispanics had 25(OH)D3 levels below 20 ng/mL. The 25(OH)D3 level below 20 ng/mL was significantly associated with breast cancer in both African-Americans (OR = 2.5, 95% CI = 1.3-4.8) and Hispanics (OR = 1.9, 95% CI = 1.1-3.0). However, the predicted probabilities of breast cancer in African-Americans were significantly higher than in Hispanics (p < 0.001). The 25(OH)D3 below 20 ng/mL was significantly associated with triple negative breast cancer (TNBC) in African-Americans (OR = 5.4, p = 0.02, 95% CI = 1.4-15), but not in Hispanics in our cohort of participants. Levels of 25(OH)D3 below 26 ng/mL predicts a decrease in disease-free survival, but it was not an independent predictor. Conclusions: Our data shows an association between 25(OH)D3 levels and the risk of breast cancer. Further studies on the relationship between 25(OH)D3 level and breast cancer risk are warranted.

1α,25-Dihydroxyvitamin D3 up-regulates IL-34 expression in SH-SY5Y neural cells

Vitamin D supplementation is regarded as a novel approach to treat Alzheimer’s disease, but the underlying mechanism remains elusive. The cytokine IL-34 provides strong neuroprotective and survival signals in brain injury and neurodegeneration and could be an immunological mediator for the vitamin D-induced protection. The aim of this study was to investigate whether human IL-34 is up-regulated in neuronal cells by the hormonally active form of vitamin D, 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3]. We found that IL-34 was detectable in a variety of cell lines and its expression was strongly induced in SH-SY5Y neural cells in a dose- and time-dependent manner by 1α,25(OH)2D3 through the vitamin D receptor (VDR). Furthermore, we identified the core promoter of IL-34 gene and a VDR binding site (CGCCCT) that was required for 1α,25(OH)2D3-induced IL-34 expression. These findings suggest that the induction of IL-34 expression by 1α,25(OH)2D3 may constitute a mechanism that explains the protective function of vitamin D in Alzheimer’s disease.

Changes in bone metabolic parameters following oral calcium supplementation in an adult patient with vitamin D-dependent rickets type 2A

Vitamin D-dependent rickets type 2A (VDDR2A) is a rare inherited disorder with decreased tissue responsiveness to 1,25-dihydroxyvitamin D [1,25(OH)₂D], caused by loss of function mutations in the vitamin D receptor (VDR) gene. Approximately 50 types of mutations have been identified so far that change amino acids in either the N-terminal DNA binding domain (DBD) or the C-terminal ligand binding domain (LBD) of the VDR protein. The degree of responsiveness to 1,25(OH)₂D varies between patients with VDDR2A, which may depend on their residual VDR function. In this report, we describe a female patient with VDDR2A caused by an early stop codon (R30X) in the VDR gene that resulted in a severely truncated VDR protein. She developed alopecia and bowed legs within a year after birth and was diagnosed with rickets at the age of 2. She had been treated with active vitamin D and oral calcium supplementation until 22 years of age, when she developed secondary hyperparathyroidism and high bone turnover. The genetic diagnosis of VDDR2A promoted the discontinuation of active vitamin D treatment in favor of monotherapy with oral calcium supplementation. We observed amelioration of the secondary hyperparathyroidism and normalization of bone metabolic parameters within 6 years.

Effects of 1alpha, 25-dihydroxyvitamin D3 on programmed cell death of Ishikawa endometrial cancer cells through ezrin phosphorylation

This study investigated the effects of 1α, 25-dihydroxyvitamin D₃-induced cell death and its underlying molecular mechanisms in Ishikawa endometrial carcinoma cells. The effects of 1α, 25-dihydroxyvitamin D₃ on Ishikawa cells were examined by 3-[4,5-dimethylthiazol-2-yl]-2.5-diphenyl-tetrazolium bromide, thiazolyl blue (MTT) assay. 1α, 25-dihydroxyvitamin D₃ was shown to induce programmed cell death in Ishikawa endometrial carcinoma cells by activation of caspase-3 and caspase-9, along with elevation of Bcl-2 and Bcl-xL. Cell viability was reduced by 1α, 25-dihydroxyvitamin D₃ in a concentration-dependent manner up to 2.5 μM. In addition, ezrin phosphorylation increased with the 1α, 25-dihydroxyvitamin D₃ concentration (0-0.5 μM). The protein level of caspase-9 was increased by 1α, 25-dihydroxyvitamin D₃ up to 0.5 μM. This is the first report regarding the efficacy and molecular mechanisms underlying the effects of 1α, 25-dihydroxyvitamin D₃ in endometrial cancer cells. Our findings indicate that 1α, 25-dihydroxyvitamin D₃ induces endometrial cancer cell death in a concentration-dependent manner. Impact statement Up to date, there is no report about the efficacy and molecular underlying mechanisms on the effect of vitamin D₃ in endometrial cancer cells. Our findings indicate that 1α, 25-dihydroxyvitamin D_3. which is an active metabolite of vitamin D₃, induces Ishikawa endometrial cancer cell death in a concentration-dependent manner by activation of caspase-3 and -9, along with elevation of Bcl-2 and Bcl-xL. In addition, the same concentration of 1α, 25-dihydroxyvitamin D₃ that provoked apoptotic signals caused phosphorylation of ezrin at threonine 567 in a VDR-dependent manner. This study suggests that 1α, 25-dihydroxyvitamin D₃ within the optimal range (0.5 uM) would induce apoptosis through Fas-ezrin-caspase-3, -8, -9 signalling axis which may be a critical cell death regulator in Ishikawa endometrial cancer cell. Further study will be more interesting to address molecular connections or prove this critical optimal concentration range of vitamin D.

Vitamin D Metabolite, 25-Hydroxyvitamin D, Regulates Lipid Metabolism by Inducing Degradation of SREBP/SCAP

Sterol regulatory element-binding proteins (SREBPs) are transcription factors that control lipid homeostasis. SREBP activation is regulated by a negative feedback loop in which sterols bind to SREBP cleavage-activating protein (SCAP), an escort protein essential for SREBP activation, or to insulin-induced genes (Insigs) (endoplasmic reticulum [ER] anchor proteins), sequestering the SREBP-SCAP-Insig complex in the ER. We screened a chemical library of endogenous molecules and identified 25-hydroxyvitamin D (25OHD) as an inhibitor of SREBP activation. Unlike sterols and other SREBP inhibitors, 25OHD impairs SREBP activation by inducing proteolytic processing and ubiquitin-mediated degradation of SCAP, thereby decreasing SREBP levels independently of the vitamin D receptor. Vitamin D supplementation has been proposed to reduce the risk of metabolic diseases, but the mechanisms are unknown. The present results suggest a previously unrecognized molecular mechanism of vitamin D-mediated lipid control that might be useful in the treatment of metabolic diseases.

Regulation of calcitriol biosynthesis and activity: focus on gestational vitamin D deficiency and adverse pregnancy outcomes

Vitamin D has garnered a great deal of attention in recent years due to a global prevalence of vitamin D deficiency associated with an increased risk of a variety of human diseases. Specifically, hypovitaminosis D in pregnant women is highly common and has important implications for the mother and lifelong health of the child, since it has been linked to maternal and child infections, small-for-gestational age, preterm delivery, preeclampsia, gestational diabetes, as well as imprinting on the infant for life chronic diseases. Therefore, factors that regulate vitamin D metabolism are of main importance, especially during pregnancy. The hormonal form and most active metabolite of vitamin D is calcitriol. This hormone mediates its biological effects through a specific nuclear receptor, which is found in many tissues including the placenta. Calcitriol synthesis and degradation depend on the expression and activity of CYP27B1 and CYP24A1 cytochromes, respectively, for which regulation is tissue specific. Among the factors that modify these cytochromes expression and/or activity are calcitriol itself, parathyroid hormone, fibroblast growth factor 23, cytokines, calcium and phosphate. This review provides a current overview on the regulation of vitamin D metabolism, focusing on vitamin D deficiency during gestation and its impact on pregnancy outcomes.

Obesity and cancer: the role of vitamin D

Background

It is estimated that 20% of all cancer cases are caused by obesity. Vitamin D is thought to be one of the mechanisms underlying this association. This review aims to summarise the evidence for the mediating effect of vitamin D on the link between obesity and cancer.

Methods

Three literature searches using PubMed and Embase were conducted to assess whether vitamin D plays an important role in the pathway between obesity and cancer: (1) obesity and cancer; (2) obesity and vitamin D; and (3) vitamin D and cancer. A systematic review was performed for (1) and (3), whereas a meta-analysis including random effects analyses was performed for (2).

Results

(1) 32 meta-analyses on obesity and cancer were identified; the majority reported a positive association between obesity and risk of cancer. (2) Our meta-analysis included 12 original studies showing a pooled relative risk of 1.52 (95% CI: 1.33-1.73) for risk of vitamin D deficiency (<50 nmol/L) in obese people (body mass index >30 kg/m²). (3) 21 meta-analyses on circulating vitamin D levels and cancer risk were identified with different results for different types of cancer.

Conclusion

There is consistent evidence for a link between obesity and cancer as well as obesity and low vitamin D. However, it seems like the significance of the mediating role of vitamin D in the biological pathways linking obesity and cancer is low. There is a need for a study including all three components while dealing with bias related to dietary supplements and vitamin D receptor polymorphisms.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-712) contains supplementary material, which is available to authorized users.

Vitamin D and the RNA transcriptome: more than mRNA regulation

The GRCh37.p13 primary assembly of the human genome contains 20805 protein coding mRNA, and 37147 non-protein coding genes and pseudogenes that as a result of RNA processing and editing generate 196501 gene transcripts. Given the size and diversity of the human transcriptome, it is timely to revisit what is known of VDR function in the regulation and targeting of transcription. Early transcriptomic studies using microarray approaches focused on the protein coding mRNA that were regulated by the VDR, usually following treatment with ligand. These studies quickly established the approximate size, and surprising diversity of the VDR transcriptome, revealing it to be highly heterogenous and cell type and time dependent. With the discovery of microRNA, investigators also considered VDR regulation of these non-protein coding RNA. Again, cell and time dependency has emerged. Attempts to integrate mRNA and miRNA regulation patterns are beginning to reveal patterns of co-regulation and interaction that allow for greater control of mRNA expression, and the capacity to govern more complex cellular events. As the awareness of the diversity of non-coding RNA increases, it is increasingly likely it will be revealed that VDR actions are mediated through these molecules also. Key knowledge gaps remain over the VDR transcriptome. The causes for the cell and type dependent transcriptional heterogenetiy remain enigmatic. ChIP-Seq approaches have confirmed that VDR binding choices differ very significantly by cell type, but as yet the underlying causes distilling VDR binding choices are unclear. Similarly, it is clear that many of the VDR binding sites are non-canonical in nature but again the mechanisms underlying these interactions are unclear. Finally, although alternative splicing is clearly a very significant process in cellular transcriptional control, the lack of RNA-Seq data centered on VDR function are currently limiting the global assessment of the VDR transcriptome. VDR focused research that complements publically available data (e.g., ENCODE Birney et al., 2007; Birney, 2012), TCGA (Strausberg et al., 2002), GTEx (Consortium, 2013) will enable these questions to be addressed through large-scale data integration efforts.

New insights on membrane mediated effects of 1α,25-dihydroxy vitamin D3 signaling in the musculoskeletal system

1α,25-Dihydroxy vitamin D3 [1α,25(OH)2D3] acts on cells via classical steroid hormone receptor-mediated gene transcription and by initiating rapid membrane-mediated signaling pathways. Two receptors have been implicated to play roles in 1α,25(OH)2D3 mediated rapid signaling, the classical nuclear vitamin D receptor (VDR) and protein disulfide isomerase, family A, member 3 (Pdia3). Long term efforts to investigate the roles of these two receptors demonstrated thatPdia3 is located in caveolae, where it interacts with phospholipase A2 (PLA2) activating protein (PLAA) and caveolin-1 (Cav-1) to initiate rapid signaling via Ca(++)/calmodulin-dependent protein kinase II (CaMKII), PLA2, phospholipase C (PLC), protein kinase C (PKC), and ultimately the ERK1/2 family of mitogen activated protein kinases (MAPK). VDR is present on the plasma membrane, and it is required for 1α,25(OH)2D3 induced rapid activation of Src. PDIA3+/- mice demonstrate an impaired musculoskeletal phenotype. Moreover, our studies examining mineralization of pre-osteoblasts in 3D culture have shown the physiological importance of Pdia3 and VDR interaction: knockdown of Pdia3 or VDR is characterized by impaired mineralization of the constructs.

Synthesis and Biological Activity of Diastereomeric and Geometric Analogs of Calcipotriol, PRI-2202 and PRI-2205, Against Human HL-60 Leukemia and MCF-7 Breast Cancer Cells

Diastereomeric and geometric analogs of calcipotriol, PRI-2202 and PRI-2205, were synthesized as advanced intermediates from vitamin D C-22 benzothiazoyl sulfones and side-chain aldehydes using our convergent strategy. Calcitriol, calcipotriol (PRI-2201) and tacalcitol (PRI-2191) were used as the reference compounds. Among a series of tested analogs the diastereomeric analog PRI-2202 showed the strongest antiproliferative activity on the human breast cancer cell line MCF-7, whereas the geometric analog PRI-2205 was the weakest. Both analogs were less potent in antiproliferative activity against HL-60 cells compared to the reference compounds. The ability to potentiate antiproliferative effect of cisplatin or doxorubicin against HL-60 cells or that of tamoxifen against the MCF-7 cell line was observed at higher doses of PRI-2202 or PRI-2205 than those of the reference compounds. The proapoptotic activity of tamoxifen, expressed as the diminished mitochondrial membrane potential, as well as the increased phosphatidylserine expression, was partially attenuated by calcitriol, PRI-2191, PRI-2201 and PRI-2205. The treatment of the MCF-7 cells with tamoxifen alone resulted in an increase in VDR expression. Moreover, a further increase in VDR expression was observed when the analogs PRI-2201 or PRI-2205, but not PRI-2191, were used in combination with tamoxifen. This observation could partially explain the potentiation of the antiproliferative effect of tamoxifen by vitamin D analogs.

[Vitamin D and breast cancer: physiopathology, biological and clinical implications]

There is a recent increase in interest of vitamin D and breast cancer, facing the number of publications on the subject. This increase have several reasons, on the one hand, vitamin D deficiency is more and more prevalent and, on the other hand, there are new data that highlights the extra-bone effects of vitamin D, especially in breast cancer, the vitamin D is involved in the breast cancer risk factor, the prognosis, and the interaction with breast cancer treatments. This combination between vitamin D deficiency and breast cancer is extremely usual, and combined with all cancer clinical parameters: the incidence, the tumour biology, the clinical presentation, the prognosis, and the antineoplastic treatment tolerance. This vitamin D deficiency is increased after adjuvant cancer treatments. And yet, this problem increases bone metabolism disruptions in breast cancer patients, inducing osteoporotic risk at long time, even though this population is curable. This problem is therefore serious in the adjuvant breast cancer treatment. Unfortunately, in this population, the current recommendations are clearly insufficient, and the current randomized clinical trial results would contribute to define the best way to correct the vitamin D deficiency, quickly and secure.

Differential regulation of TauT by calcitriol and retinoic acid via VDR/RXR in LLC-PK1 and MCF-7 cells

The interaction between taurine and the absorption of fat-soluble -vitamins, such as vitamin A and D, has been an interesting topic in the field of -nutrition science, because taurine-conjugated bile acid optimizes fat and fat-soluble vitamin absorption. However, whether the hormone calcitriol (1,25-dihydroxyvitamin D(3)) and retinoic acid regulate the expression of the TauT gene is unknown. In this study, we test the hypothesis that the TauT gene is regulated by vitamin D(3) (VD(3)) and retinoic acid (RA) via activation of the vitamin D receptor (VDR) and retinoic acid receptor (RXR). Taurine uptake, Western blotting, gene reporter assay, and immunohistochemical analysis of TauT, VDR, and RXR were used in VD(3)- and/or RA-treated LLC-PK1 and MCF-7 cells. We demonstrated that VD(3) alone had little effect on TauT expression in both LLC-PK1 and MCF-7 cells. Expression of TauT was significantly increased by RA, which was synergized by the addition of VD(3) after RXR activation in LLC-PK1 cells. In contrast, expression of TauT was significantly decreased by the combination of VD(3) and RA in MCF-7 cells. Regulation of TauT by VD(3)/RA appears to occur at the transcriptional level, as determined by a reporter gene assay of the TauT promoter. Immunohistochemical study showed that VDR and RXR were activated by VD(3) and RA, respectively, in both LLC-PK1 and MCF-7 cells. The activated VDR and RXR also colocated in nuclei of both cells, suggesting that a VDR/RXR complex is involved in the transcriptional regulation of TauT. Our results show that expression of TauT is differentially regulated by VD(3) and RA via formation of VDR and RXR complexes in the nuclei in a cell type-dependent manner.

Chaperone properties of pdia3 participate in rapid membrane actions of 1α,25-dihydroxyvitamin d3

Protein disulfide isomerase family A, member 3 (Pdia3) mediates many of the plasma membrane (PM)-associated rapid responses to 1α,25-dihydroxyvitamin D3 (1α,25[OH]2D3). It is not well understood how Pdia3, which is an endoplasmic reticulum (ER) chaperone, functions as a PM receptor for 1α,25(OH)2D3. We mutated 3 amino acids (K214 and R282 in the calreticulin interaction site and C406 in the isomerase catalytic site), which are important for Pdia3's ER chaperone function, and examined their role in responses to 1α,25(OH)2D3. Pdia3 constructs with and without the ER retention signal KDEL were used to investigate the PM requirement for Pdia3. Finally, we determined whether palmitoylation and/or myristoylation were required for Pdia3-mediated responses to 1α,25(OH)2D3. Overexpressing the Pdia3 R282A mutant in MC3T3-E1 cells increased PM phospholipase A2-activating protein, Rous sarcoma oncogene (c-Src), and caveolin-1 but blocked increases in 1α,25(OH)2D3-stimulated protein kinase C (PKC) seen in cells overexpressing wild-type Pdia3 (Pdia3Ovr cells). Cells overexpressing Pdia3 with K214A and C406S mutations had PKC activity comparable to untreated controls, indicating that the native response to 1α,25(OH)2D3 also was blocked. Overexpressing Pdia3[-KDEL] increased PM localization and augmented baseline PKC, but the stimulatory effect of 1α,25(OH)2D3 was comparable to that seen in wild-type cultures. In contrast, 1α,25(OH)2D3 increased prostaglandin E2 in Pdia3[±KDEL] cells. Although neither palmitoylation nor myristoylation was required for PM association of Pdia3, myristoylation was needed for PKC activation. These data indicate that both the chaperone functional domains and the subcellular location of Pdia3 control rapid membrane responses to 1α,25(OH)2D3.

Plasma 25 hydroxyvitamin D level and blood gene expression profiles: a cross-sectional study of the Norwegian Women and Cancer Post-genome Cohort

BACKGROUND/OBJECTIVES

Vitamin D deficiency has been associated with increased risk of developing several diseases, but much is unknown about the molecular effects involved. Gene expression technology is increasingly being used to elucidate molecular mechanisms related to nutritional factors, and in this study of free-living, middle-aged Norwegian women, we aimed at identifying gene expression pathways in the blood associated with vitamin D status.

SUBJECTS/METHODS

Blood samples and questionnaires were collected as a part of the Norwegian Women and Cancer Post-genome Cohort (500 invited subjects, 218 included). Plasma 25 hydroxyvitamin D (25(OH)D) concentrations were measured using high-performance liquid chromatography, and we compared groups with sufficient versus deficient vitamin D status (25(OH)D >50 nmol/l (n=66) versus <37.5 nmol/l (n=83)), to identify differences in gene expression profiles obtained using full-genome microarrays.

RESULTS

In a targeted pathway-level analysis, several immunological processes, immune cell functions and major signaling pathways were differentially regulated according to vitamin D status (P<0.01). To a certain degree, results from in vitro studies reported in the literature were reflected in this population setting.

CONCLUSIONS

We conclude that vitamin D status measured as 25(OH)D was associated with molecular pathways that may ultimately affect the potential onset of diseases. The use of gene expression analysis in a population setting may give valuable input to the study of effects of nutritional factors.

Differences in transcriptional effects of 1α,25 dihydroxyvitamin D3 on fibroblasts associated to breast carcinomas and from paired normal breast tissues

The effects of 1α,25 dihydroxyvitamin D3 (1,25D) on breast carcinoma associated fibroblasts (CAFs) are still unknown. This study aimed to identify genes whose expression was altered after 1,25D treatment in CAFs and matched adjacent normal mammary associated fibroblasts (NAFs). CAFs and NAFs (from 5 patients) were cultured with or without (control) 1,25D 100 nM. Both CAF and NAF expressed vitamin D receptor (VDR) and 1,25D induction of the genomic pathway was detected through up-regulation of the target gene CYP24A1. Microarray analysis showed that despite presenting 50% of overlapping genes, CAFs and NAFs exhibited distinct transcriptional profiles after 1,25D treatment (FDR<0.05). Functional analysis revealed that in CAFs, genes associated with proliferation (NRG1, WNT5A, PDGFC) were down regulated and those involved in immune modulation (NFKBIA, TREM-1) were up regulated, consistent with anti tumor activities of 1,25D in breast cancer. In NAFs, a distinct subset of genes was induced by 1,25D, involved in anti apoptosis, detoxification, antibacterial defense system and protection against oxidative stress, which may limit carcinogenesis. Co-expression network and interactome analysis of genes commonly regulated by 1,25D in NAFs and CAFs revealed differences in their co-expression values, suggesting that 1,25D effects in NAFs are distinct from those triggered in CAFs.

New vitamin D analogs as potential therapeutics in melanoma

Extensive evidence shows that the active form of vitamin D3--1α,25-dihydroxyvitamin D3--plays an important role in cancer prevention, has tumorostatic activity and may potentially be used in therapy for melanoma. Vitamin D3 and its analogs (secosteroids) exert multiple effects on cancer cells, including inhibition of cell growth and induction of differentiation. Activity of secosteroids depends on multiple cellular factors, including expression of the vitamin D receptor. Despite its endogenous origin, the key drawback for the use of pharmacologically effective doses of 1α,25-dihydroxyvitamin D3 is its hypercalcemic effect leading to profound toxicity. The solution may lie in properties of vitamin D3 analogs with modified side chains, which demonstrate low calcemic activity but conserve the anti-tumor properties. Noncalcemic vitamin D compounds were found to be potent in multiple studies that mandate further clinical testing. Finally, recent studies revealed alternative metabolic pathways for secosteroids and new targets in the cells, which opens up new therapeutic possibilities.

Molecular aspects of vitamin D anticancer activity

Environment may influence the development and prevention of cancer. Calcitriol has been associated with calcium homeostasis regulation. Many epidemiological, biochemical, and genetic studies have shown non-classic effects of vitamin D, such as its involvement in the progression of different cancers. Although vitamin D induces cellular arrest, triggers apoptotic pathways, inhibits angiogenesis, and alters cellular adhesion, the precise mechanisms of its action are still not completely established. This article will present a revision about the molecular aspects proposed to be involved in the anticancer action of calcitriol. Adequate levels of vitamin D to prevent cancer development will also be discussed.

TARGETgene: a tool for identification of potential therapeutic targets in cancer

The vast array of in silico resources and data of high throughput profiling currently available in life sciences research offer the possibility of aiding cancer gene and drug discovery process. Here we propose to take advantage of these resources to develop a tool, TARGETgene, for efficiently identifying mutation drivers, possible therapeutic targets, and drug candidates in cancer. The simple graphical user interface enables rapid, intuitive mapping and analysis at the systems level. Users can find, select, and explore identified target genes and compounds of interest (e.g., novel cancer genes and their enriched biological processes), and validate predictions using user-defined benchmark genes (e.g., target genes detected in RNAi screens) and curated cancer genes via TARGETgene. The high-level capabilities of TARGETgene are also demonstrated through two applications in this paper. The predictions in these two applications were then satisfactorily validated by several ways, including known cancer genes, results of RNAi screens, gene function annotations, and target genes of drugs that have been used or in clinical trial in cancer treatments. TARGETgene is freely available from the Biomedical Simulations Resource web site (http://bmsr.usc.edu/Software/TARGET/TARGET.html).

Mechanism of Pdia3-dependent 1α,25-dihydroxy vitamin D3 signaling in musculoskeletal cells

1α,25-Dihydroxy vitamin D3 [1,25(OH)2D3] acts on cells through traditional steroid hormone receptor-mediated gene transcription and by initiating rapid membrane-associated signaling pathways. Two receptors have been implicated in rapid signaling by 1,25(OH)2D3, the classical nuclear vitamin D receptor (VDR) and the more recently identified protein disulfide isomerase, family A, member 3 (Pdia3). Our lab along with other groups has established various tools to investigate the role of these two receptors, including gene knock-out, conditional knock-out, silencing, and over-expression in various model systems (growth plate chondrocytes, osteoblastic cells, chick intestinal epithelial cells, mouse embryoid bodies, extracellular matrix vesicles and isolated cell membranes). The data demonstrate the requirement for Pdia3 in 1,25(OH)2D3 induced phospholipase A2 (PLA2) and protein kinase C (PKC) activation and downstream responses. Pdia3+/- heterozygote mice also exhibit both cartilage and bone defects. VDR is present on the plasma membrane and one VDR-/- mouse strain lacks transcaltachia, although 1,25(OH)2D3 induced PKC activation and transcaltachia are not affected in another VDR-/- mouse strain. In the context of osteoblast differentiation, both receptors are expressed during osteogenic commitment of embryoid bodies and silencing of each causes a more mature osteoblast phenotype in MC3T3-E1 pre-osteoblasts. Pdia3 exists in caveolae, where it interacts with PLA2 activating protein (PLAA) and caveolin-1 to initiate rapid signaling via PLA2, phospholipase C (PLC), PKC, and ultimately the ERK1/2 family of mitogen activated protein kinases (MAPK). Using the growth plate chondrocyte and matrix vesicle models, we have demonstrated that Pdia3-dependent signaling in response to 1,25(OH)2D3 regulates growth plate physiology.

Cellular and molecular effects of vitamin D on carcinogenesis

Epidemiologic data suggest that the incidence and severity of many types of cancer inversely correlates with indices of vitamin D status. The vitamin D receptor (VDR) is highly expressed in epithelial cells at risk for carcinogenesis including those resident in skin, breast, prostate and colon, providing a direct molecular link by which vitamin D status impacts on carcinogenesis. Consistent with this concept, activation of VDR by its ligand 1,25-dihydroxyvitamin D (1,25D) triggers comprehensive genomic changes in epithelial cells that contribute to maintenance of the differentiated phenotype, resistance to cellular stresses and protection of the genome. Many epithelial cells also express the vitamin D metabolizing enzyme CYP27B1 which enables autocrine generation of 1,25D from the circulating vitamin D metabolite 25-hydroxyvitamin D (25D), critically linking overall vitamin D status with cellular anti-tumor actions. Furthermore, pre-clinical studies in animal models has demonstrated that dietary supplementation with vitamin D or chronic treatment with VDR agonists decreases tumor development in skin, colon, prostate and breast. Conversely, deletion of the VDR gene in mice alters the balance between proliferation and apoptosis, increases oxidative DNA damage, and enhances susceptibility to carcinogenesis in these tissues. Because VDR expression is retained in many human tumors, vitamin D status may be an important modulator of cancer progression in persons living with cancer. Collectively, these observations have reinforced the need to further define the molecular actions of the VDR and the human requirement for vitamin D in relation to cancer development and progression.

Vitamin D and the mammary gland: a review on its role in normal development and breast cancer

Breast cancer is a heterogeneous disease associated with diverse biological behaviours and clinical outcome. Although some molecular subgroups of breast cancer have a targeted therapy, the most aggressive tumours still lack a molecular target. Despite vitamin D being classically associated with the physiological role of calcium regulation and phosphate transport in bone metabolism, several studies have demonstrated a wide range of functions for this hormone, which are particularly important in the field of cancer. The mechanisms underlying the protective actions of vitamin D in cancer development are only sparsely understood, but evidence shows that vitamin D participates in cell growth regulation, apoptosis and cell differentiation. In addition, it has been implicated in the suppression of cancer cell invasion, angiogenesis and metastasis. Most of vitamin D biological actions are mediated by the vitamin D receptor and the synthesis and catabolism of this hormone are regulated by the enzymes CYP27B1 and CYP24A1. In the present review we highlight research data concerning the function of this hormone in the mammary gland, with a special focus on breast carcinogenesis. Hence, and although the available data are controversial, we consider not only updated information on the epidemiology of vitamin D in breast cancer and its potential value as a therapeutic agent or prophylactic (with an emphasis on molecular mechanisms and effectors of vitamin D action), but include data on its role in other stages of breast cancer progression as well. Accordingly, we review data on the influence of vitamin D in the development of normal breast and the expression of vitamin D-related proteins (VDR, CYP27B1 and CYP24A21) in benign mammary lesions and ductal carcinomas in situ.

Dual functions of autophagy in the response of breast tumor cells to radiation: cytoprotective autophagy with radiation alone and cytotoxic autophagy in radiosensitization by vitamin D 3

In MCF-7 breast tumor cells, ionizing radiation promoted autophagy that was cytoprotective; pharmacological or genetic interference with autophagy induced by radiation resulted in growth suppression and/or cell killing (primarily by apoptosis). The hormonally active form of vitamin D, 1,25D 3, also promoted autophagy in irradiated MCF-7 cells, sensitized the cells to radiation and suppressed the proliferative recovery that occurs after radiation alone. 1,25D 3 enhanced radiosensitivity and promoted autophagy in MCF-7 cells that overexpress Her-2/neu as well as in p53 mutant Hs578t breast tumor cells. In contrast, 1,25D 3 failed to alter radiosensitivity or promote autophagy in the BT474 breast tumor cell line with low-level expression of the vitamin D receptor. Enhancement of MCF-7 cell sensitivity to radiation by 1,25D 3 was not attenuated by a genetic block to autophagy due largely to the promotion of apoptosis via the collateral suppression of protective autophagy. However, MCF-7 cells were protected from the combination of 1,25D 3 with radiation using a concentration of chloroquine that produced minimal sensitization to radiation alone. The current studies are consistent with the premise that while autophagy mediates a cytoprotective function in irradiated breast tumor cells, promotion of autophagy can also confer radiosensitivity by vitamin D (1,25D 3). As both cytoprotective and cytotoxic autophagy can apparently be expressed in the same experimental system in response to radiation, this type of model could be utilized to distinguish biochemical, molecular and/or functional differences in these dual functions of autophagy.

Regulation of RUNX2 transcription factor-DNA interactions and cell proliferation by vitamin D3 (cholecalciferol) prohormone activity

The fat-soluble prohormone cholecalciferol (Vitamin D3) is a precursor of the circulating 25-OH Vitamin D3, which is converted by 1α-hydroxylase to the biologically active 1,25-OH Vitamin D3. Active Vitamin D3 interacts with the Vitamin D receptor (VDR), a transcription factor that plays an important role in calcium mobilization and bone formation. RUNX2 is a DNA-binding transcription factor that regulates target genes important in bone formation, angiogenesis, and cancer metastasis. Using computer-assisted drug design (CADD) and a microtiter plate-based DNA-binding enzyme-linked immunosorbent assay (D-ELISA) to measure nuclear RUNX2 DNA binding, we have found that Vitamin D3 prohormones can modulate RUNX2 DNA binding, which was dose-dependent and sensitive to trypsin, salt, and phosphatase treatment. Unlabeled oligonucleotide or truncated, dominant negative RUNX2 proteins were competitive inhibitors of RUNX2 DNA binding. The RUNX2 heterodimeric partner, Cbfβ, was detected in the binding complexes with specific antibodies. Evaluation of several RUNX2:DNA targeted small molecules predicted by CADD screening revealed a previously unknown biological activity of the inactive Vitamin D3 precursor, cholecalciferol. Cholecalciferol modulated RUNX2:DNA binding at nanomolar concentrations even in cells with low VDR. Cholecalciferol and 25-OH Vitamin D3 prohormones were selective inhibitors of RUNX2-positive endothelial, bone, and breast cancer cell proliferation, but not of cells lacking RUNX2 expression. These compounds may have application in modulating RUNX2 activity in an angiogenic setting, in metastatic cells, and to promote bone formation in disease-mediated osteoporosis. The combination CADD discovery and D-ELISA screening approaches allows the testing of other novel derivatives of Vitamin D and/or transcriptional inhibitors with the potential to regulate DNA binding and biological function.

Vitamin D and cancer: a review of molecular mechanisms

The population-based association between low vitamin D status and increased cancer risk can be inconsistent, but it is now generally accepted. These relationships link low serum 25OHD (25-hydroxyvitamin D) levels to cancer, whereas cell-based studies show that the metabolite 1,25(OH)2D (1,25-dihydroxyvitamin D) is a biologically active metabolite that works through vitamin D receptor to regulate gene transcription. In the present review we discuss the literature relevant to the molecular events that may account for the beneficial impact of vitamin D on cancer prevention or treatment. These data show that although vitamin D-induced growth arrest and apoptosis of tumour cells or their non-neoplastic progenitors are plausible mechanisms, other chemoprotective mechanisms are also worthy of consideration. These alternative mechanisms include enhancing DNA repair, antioxidant protection and immunomodulation. In addition, other cell targets, such as the stromal cells, endothelial cells and cells of the immune system, may be regulated by 1,25(OH)2D and contribute to vitamin D-mediated cancer prevention.

Vitamin D status in paediatric patients with cancer

BACKGROUND

Children with malignant disease are at increased risk of bone disorders and cardiovascular disease. Vitamin D status may influence this risk and so we assessed vitamin D levels in children with malignant disease undergoing active treatment or surveillance post-therapy.

PROCEDURE

This was an outpatient-based cross-sectional study of 61 children with a history of malignancy (median age 11.1 years; range 1.5-24.4 years) and 60 control subjects (median age 8.4 years; range 0.2-18.0 years) attending hospital for the management of non-malignant disorders. Serum vitamin D (25-OH-D), parathormone levels and bone biochemistry were determined. Vitamin D status and its relationship to age, sex, ethnicity, time of sampling and presence of malignant disease was determined.

RESULTS

Vitamin D status was suboptimal in 62% of cases (25-OH-D < 50 nmol/L [20 ng/ml]). Vitamin D deficiency (25-OH-D < 25 nmol/L [10 ng/ml]) was more common in children with malignant disease than controls (21.3% vs. 3.3%; P = 0.013). Month of sampling (P < 0.001), ethnicity (P < 0.001), older age (P = 0.011), and history of malignancy (P = 0.012) were associated with a poorer vitamin D status.

CONCLUSIONS

Vitamin D levels [25-OH-D] are lower in survivors of childhood cancer in comparison to control children with the majority either insufficient or deficient. Assessment and adequate replacement of vitamin D status may be of particular value in this group of children.

Cancer prevalence in osteoporotic women with low serum vitamin D levels

OBJECTIVE

The aim of this study was to assess the role of vitamin D in cancer development in postmenopausal osteoporotic women.

METHODS

A cross-sectional and in vitro study was carried out, with statistical analysis with odds ratios and 95% CIs presented. Human estrogen receptor-positive breast cancer cells (MCF-7) were studied in vitro. The apoptosis-to-proliferation (A/P) ratio was also determined.

RESULTS

A total of 885 women were included in this study. Any kind of cancer was found in 112 (12.7%) of all women. Breast cancer was the most prevalent malignancy, representing half of the cases (n = 56, 50%). The prevalence of any kind of cancer and breast cancer in women with low 25-hydroxyvitamin D3 levels (25OHD; <50 nmol/L) was higher than in women with high 25OHD levels (≥ 50 nmol/L). The in vitro study demonstrated a statistically significant increased A/P ratio of 5.27 (95% CI, 4.054-6.493) with a high concentration of 1α,25-dihydroxyvitamin D (10 μM) after 96 hours.

CONCLUSIONS

Osteoporotic women with low serum levels of 25OHD (<50 nmol/L) have an increased prevalence of any kind of cancer and breast cancer; however, these differences are not statistically significant. 1α,25-dihydroxyvitamin D induced an increased A/P ratio in MCF-7 breast cancer cells in vitro.