Anti-tumor activity of calcitriol: pre-clinical and clinical studies

1,25-Dihydroxyvitamin D3 Suppresses Prognostic Survival Biomarkers Associated with Cell Cycle and Actin Organization in a Non-Malignant African American Prostate Cell Line

Vitamin D3 is a steroid hormone that confers anti-tumorigenic properties in prostate cells. Serum vitamin D3 deficiency has been associated with advanced prostate cancer (PCa), particularly affecting African American (AA) men. Therefore, elucidating the pleiotropic effects of vitamin D on signaling pathways, essential to maintaining non-malignancy, may provide additional drug targets to mitigate disparate outcomes for men with PCa, especially AA men. We conducted RNA sequencing on an AA non-malignant prostate cell line, RC-77N/E, comparing untreated cells to those treated with 10 nM of vitamin D3 metabolite, 1α,25(OH)2D3, at 24 h. Differential gene expression analysis revealed 1601 significant genes affected by 1α,25(OH)2D3 treatment. Pathway enrichment analysis predicted 1α,25(OH)2D3- mediated repression of prostate cancer, cell proliferation, actin cytoskeletal, and actin-related signaling pathways (p < 0.05). Prioritizing genes with vitamin D response elements and associating expression levels with overall survival (OS) in The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA PRAD) cohort, we identified ANLN (Anillin) and ECT2 (Epithelial Cell Transforming 2) as potential prognostic PCa biomarkers. Both genes were strongly correlated and significantly downregulated by 1α,25(OH)2D3 treatment, where low expression was statistically associated with better overall survival outcomes in the TCGA PRAD public cohort. Increased ANLN and ECT2 mRNA gene expression was significantly associated with PCa, and Gleason scores using both the TCGA cohort (p < 0.05) and an AA non-malignant/tumor-matched cohort. Our findings suggest 1α,25(OH)2D3 regulation of these biomarkers may be significant for PCa prevention. In addition, 1α,25(OH)2D3 could be used as an adjuvant treatment targeting actin cytoskeleton signaling and actin cytoskeleton-related signaling pathways, particularly among AA men.

Insight into vitamin D3 action within the ovary-Basic and clinical aspects

Vitamin D3 is a fat-soluble secosteroid predominantly synthesized in the skin or delivered with a diet. Nevertheless, recently it is considered more as a hormone than a vitamin due to its pleiotropic function within the organism ensured by widely distributed vitamin D receptors and metabolic enzymes. Besides the main role in calcium and phosphorus homeostasis, vitamin D3 was shown to regulate many cellular and metabolic processes in normal and cancerous tissues within the immune system, the cardiovascular system, the respiratory system and the endocrine system. The ovary is an important extraskeletal tissue of vitamin D3 action and local metabolism, indicating its role in the regulation of ovarian functions upon physiological and pathological conditions. This chapter reviews firstly the updated information about vitamin D3 metabolism and triggered intracellular pathways. Furthermore, the basic information about ovarian physiology and several aspects of vitamin D3 effects within the ovary are presented. Finally, the special attention is paid into possible mechanism of vitamin D3 action within ovarian pathologies such as premature ovarian failure, polycystic ovary syndrome, and ovarian cancer, considering its clinical application as alternative therapy.

Pharmacokinetics and pharmacodynamics of Rh2 and aPPD ginsenosides in prostate cancer: a drug interaction perspective

Ginsenoside Rh2 and its aglycon (aPPD) are one of the major metabolites from Panax ginseng. Preclinical studies suggest that Rh2 and aPPD have antitumor effects in prostate cancer (PCa). Our aims in this review are (1) to describe the pharmacokinetic (PK) properties of Rh2 and aPPD ginsenosides; 2) to provide an overview of the preclinical findings on the use of Rh2 and aPPD in the treatment of PCa; and (3) to highlight the mechanisms of its PK and pharmacodynamic (PD) drug interactions. Increasing evidence points to the potential efficacy of Rh2 or aPPD for PCa treatment. Based on the laboratory studies, Rh2 or aPPD combinations revealed an additive or synergistic interaction or enhanced sensitivity of anticancer drugs toward PCa. This review reveals that enhanced anticancer activities were demonstrated in preclinical studies through interactions of Rh2 and/or aPPD with the proteins related to PK (e.g., cytochrome P450 enzymes, transporters) or PD of the other anticancer drugs or PCa signaling pathways. In conclusion, combining Rh2 or aPPD with anti-prostate cancer drugs leads to PK or PD interactions which could facilitate either therapeutically beneficial or toxic effects.

Gender Differences in the Effect of Calcitriol on the Body Disposition and Excretion of Doxorubicin in Mice

BACKGROUND AND OBJECTIVE

The antitumor activity and toxicity of doxorubicin are potentiated and attenuated by calcitriol, respectively. Potentially, calcitriol can be combined with doxorubicin for clinical benefit in chemotherapy. To gain insight into the interaction between doxorubicin and calcitriol, proposed for combined use in cancer treatment, we studied calcitriol's effect on the plasma pharmacokinetics, tissue distribution and excretion of doxorubicin in female and male mice.

METHODS

The control and calcitriol-treated groups, including an equal number of both sexes, received corn oil and calcitriol (2.5 μg/kg), respectively, intraperitoneally every other day for 8 days. At day 9, doxorubicin was administered intraperitoneally at a 6 mg/kg dose to each group. Doxorubicin concentrations in biologic specimens were determined by a high-performance liquid chromatographic-ultraviolet detector and analyzed using a non-compartmental model.

RESULTS

The plasma pharmacokinetics of doxorubicin were similar in the control and calcitriol-treated groups. While calcitriol did not alter the area under the plasma concentration-time curves (AUCs) and peak concentrations (C_max) of doxorubicin in the small intestine and testis, it significantly reduced the AUCs and C_max of doxorubicin in the lung, kidney, spleen, liver, stomach and ovaries. However, calcitriol increased the AUCs and C_max of doxorubicin in the heart of females, brain of males and duodenum content and vitreous humor of female and male mice. The percent cumulative urine and fecal amounts of doxorubicin in calcitriol-treated mice were higher at 89.23% and 29.37% for female mice and 118.57% and 41.65% for male mice than those in the control mice, respectively.

CONCLUSIONS

The tissue concentrations and excretion of doxorubicin in both female and male mice are influenced by calcitriol without changes in the plasma pharmacokinetics. The results from this study can provide insights to help obtain the optimal drug combination effects of doxorubicin with calcitriol in cancer treatment.

1α,25-Dihydroxyvitamin D3 synergistically enhances anticancer effects of ginsenoside Rh2 in human prostate cancer cells

1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃, commonly known as calcitriol), the most active metabolite of vitamin D₃, and ginsenoside Rh2 can regulate cellular differentiation and proliferation proteins. The purpose of the present study was to assess the effect of 1,25(OH)₂D₃ on the anticancer activities of Rh2 in human prostate cancer cells such as androgen-dependent LNCaP and androgen-independent C4-2 in vitro. The effects of treatment with 1,25(OH)₂D₃ or Rh2, either alone or in combination, on prostate cancer cells were evaluated through tetrazolium-based cell viability assay, BrdU cell proliferation rate estimation assay, and Western blot protein expression analyses of nuclear receptors (androgen receptor and vitamin D receptors) and apoptotic proteins (Bcl-2, Bax, and Caspase 3). The Combination Indices (CI) and Dose Reduction Indices (DRI) of 1,25(OH)₂D₃ and Rh2 were calculated to determine synergistic anticancer activity using Calcusyn software (Biosoft, Cambridge, UK). The cell viability assay data indicate that Rh2 treatment alone inhibited cell viability in a concentration-dependent manner and the addition of 10 nM 1,25(OH)₂D₃ to Rh2 significantly enhanced its ability to reduce cell viability up to 80 % in both the cell lines. Similarly, addition of 10 nM 1,25(OH)₂D₃ to Rh2 significantly lowered its IC₅₀ values for cell proliferation from the range of 32-65 μM to 14-8 μM in LNCaP and C4-2 cells. In addition, protein expression analyses indicated that the combined treatment with Rh2 and 1,25(OH)₂D₃ led to greater downregulation of androgen receptor expression compared to single agent exposure. Similarly, the presence of 1,25(OH)₂D₃ synergistically increased the pro-apoptotic actions of Rh2 in both the cell lines. Overall, 1,25(OH)₂D₃ augments the Rh2-mediated anticancer effects through stimulating apoptosis and reduced cell proliferation which suggests that synergism of this combination may lead to potential lower need of the active vitamin D₃ and limited toxicity from it.

New Roles for Vitamin D Superagonists: From COVID to Cancer

Vitamin D is a potent steroid hormone that induces widespread changes in gene expression and controls key biological pathways. Here we review pathophysiology of vitamin D with particular reference to COVID-19 and pancreatic cancer. Utility as a therapeutic agent is limited by hypercalcemic effects and attempts to circumvent this problem have used vitamin D superagonists, with increased efficacy and reduced calcemic effect. A further caveat is that vitamin D mediates multiple diverse effects. Some of these (anti-fibrosis) are likely beneficial in patients with COVID-19 and pancreatic cancer, whereas others (reduced immunity), may be beneficial through attenuation of the cytokine storm in patients with advanced COVID-19, but detrimental in pancreatic cancer. Vitamin D superagonists represent an untapped resource for development of effective therapeutic agents. However, to be successful this approach will require agonists with high cell-tissue specificity.

Non-classical effects of vitamin D: Non-bone effects of vitamin D

Our understanding of vitamin D has improved considerably in recent years. The role of vitamin D in preventing osteoporotic fractures is now well-established. However, an important controversy has emerged in the last decade concerning the effects of the active form of vitamin D (1,25-dihydroxy-vitamin D) on tissues other than bone (non-classical effects). The demonstration that the vitamin D receptor (VDR) is ubiquitously, expressed combined with increasing observational data supporting a relationship between the level of 25-hydroxy-vitamin D in the serum and chronic metabolic disorders, cardiovascular disease and neoplasms, have led to its redefinition as a steroid hormone and the proposal of its use in preventing and/or treating those diseases. This article is an update on the different non-bone or non-classical effects of "vitamin-hormone D", and its potential preventive or therapeutic role in certain diseases, however, this review is not exhaustive. The different modalities of substitution or supplementation proposed in France by the Groupe de Recherche et d'Information sur les Ostéoporoses (GRIO) are also summarised.

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.

Synergistic Antitumorigenic Activity of Calcitriol with Curcumin or Resveratrol is Mediated by Angiogenesis Inhibition in Triple Negative Breast Cancer Xenografts

Calcitriol is a multitarget anticancer hormone; however, its effects on angiogenesis remain contradictory. Herein, we tested whether the antiangiogenic phytochemicals curcumin or resveratrol improved calcitriol antitumorigenic effects in vivo. Triple-negative breast cancer tumoral cells (MBCDF-T) were xenografted in nude mice, maintaining treatments for 3 weeks. Tumor onset, volume and microvessel density were significantly reduced in mice coadministered with calcitriol and curcumin (Cal+Cur). Vessel count was also reduced in mice simultaneously treated with calcitriol and resveratrol (Cal+Rsv). Cal+Cur and Cal+Rsv treatments resulted in less tumor activated endothelium, as demonstrated by decreased tumor uptake of integrin-targeted biosensors in vivo. The renal gene expression of Cyp24a1 and Cyp27b1 suggested increased calcitriol bioactivity in the combined regimens. In vitro, the phytochemicals inhibited both MBCDF-T and endothelial cells proliferation, while potentiated calcitriol’s ability to reduce MBCDF-T cell-growth and endothelial cells migration. Resveratrol induced endothelial cell death, as deduced by increased sub-G1 cells accumulation, explaining the reduced tumor vessel number in resveratrol-treated mice, which further diminished when combined with calcitriol. In conclusion, the concomitant administration of calcitriol with curcumin or resveratrol synergistically promoted anticancer effects in vitro and in vivo in human mammary tumor cells. Whereas the results suggest different mechanisms of action of the phytochemicals when coadministered with calcitriol, the converging biological effect was inhibition of tumor neoangiogenesis.

Vitamin D as A Protector of Arterial Health: Potential Role in Peripheral Arterial Disease Formation

Atherosclerotic occlusive diseases and aneurysms that affect large and medium-sized arteries outside the cardiac and cerebral circulation are collectively known as peripheral arterial disease (PAD). With a rise in the rate of aging population worldwide, the number of people diagnosed with PAD is rapidly increasing. The micronutrient vitamin D is an important steroid hormone that acts on many crucial cellular mechanisms. Experimental studies suggest that optimal levels of vitamin D have beneficial effects on the heart and blood vessels; however, high vitamin D concentrations have been implicated in promoting vascular calcification and arterial stiffness. Observations from various clinical studies shows that deficiency of vitamin D has been associated with a greater risk of PAD. Epidemiological studies have often reported an inverse relation between circulating vitamin D status measured in terms of 25-hydroxivitamin D [25(OH)D] levels and increased cardiovascular disease risk; however, randomized controlled trials did not show a consistent positive effect of vitamin D supplementation on cardiovascular disease risk or events. Even though PAD shares all the major risk factors with cardiovascular diseases, the effect of vitamin D deficiency in PAD is not clear. Current evidence suggests a strong role of vitamin D in promoting genomic and epigenomic changes. This review summarises the current literature that supports the notion that vitamin D deficiency may promote PAD formation. A better understanding of underlying pathological mechanisms will open up new therapeutic possibilities which is the main unmet need in PAD management. Furthermore, epigenetic evidence shows that a more holistic approach towards PAD prevention that incorporates a healthy lifestyle, adequate exercise and optimal nutrition may be more effective in protecting the genome and maintaining a healthy vasculature.

Do dietary calcium and vitamin D matter in men with prostate cancer?

Active surveillance (AS) is an attractive alternative to immediate treatment for men with low-risk prostate cancer. Thus, the identification of environmental factors that promote the progression of indolent disease towards aggressive stages is critical to optimize clinical management. Epidemiological studies suggest that calcium-rich diets contribute to an increased risk of developing prostate cancer and that vitamin D reduces this risk. However, the potential effect of these nutrients on the progression of early-stage prostate tumours is uncertain, as studies in this setting are scarce and have not provided unambiguous conclusions. By contrast, the results of a preclinical study from our own group demonstrate that a diet high in calcium dose-dependently accelerated the progression of early-stage prostate tumours and that dietary vitamin D prevented this effect. The extent to which the conclusions of preclinical and epidemiological studies support a role for calcium and vitamin D and the relevance of monitoring and adjustment of calcium and/or vitamin D intake in patients on AS require further investigation.

Vitamin D in prostate cancer

Signaling through the vitamin D receptor has been shown to be biologically active and important in a number of preclinical studies in prostate and other cancers. Epidemiologic data also indicate that vitamin D signaling may be important in the cause and prognosis of prostate and other cancers. These data indicate that perturbation of vitamin D signaling may be a target for the prevention and treatment of prostate cancer. Large studies of vitamin D supplementation will be required to determine whether these observations can be translated into prevention strategies. This paper reviews the available data in the use of vitamin D compounds in the treatment of prostate cancer. Clinical data are limited which support the use of vitamin D compounds in the management of men with prostate cancer. However, clinical trials guided by existing preclinical data are limited.

Association between Polymorphisms of Vitamin D Receptor and Lung Cancer Susceptibility: Evidence from an Updated Meta-analysis

Purpose: The aim of this meta-analysis was to investigate polymorphism of Bsm1, Apal, Taq1 and Cdx-2 in vitamin D receptor (VDR) associations in relation to lung cancer (LC) susceptibility.

Methods: 9 literatures were recruited into this meta-analysis from PubMed, PMC, Embase, Web of Science, Cochrane library and CNKI. STATA version 15.1 was used for statistical tests. The heterogeneity was tested using I² statistics. According to the value of I², the random-effect model (REM) or fixed-effect model (FEM) was selected to combine data from studies, respectively. Potential publication bias was evaluated by Egger's test. Sensitivity analysis was also performed to evaluate the stability and reliability in results.

Results: Decreased susceptibility of LC was found in all genetic models contrast in Bsm1 gene of VDR (a vs. A: OR = 0.62, 95 % CI = 0.44-0.87; aa vs. AA: OR = 0.76, 95 % CI = 0.60-0.96; Aa vs. AA: OR = 0.59, 95 % CI = 0.39-0.88; aa vs. AA+Aa: OR = 0.80, 95 % CI = 0.64-0.99; Aa+aa vs. AA: OR = 0.57, 95 % CI = 0.37-0.86). The similar results were also found in partial genetic models of Taq1 (a vs. A: OR = 0.88, 95 % CI = 0.79-0.98; aa vs. AA+Aa: OR = 0.84, 95 % CI = 0.73-0.98) and Cdx-2 (Aa vs. AA: OR = 0.80, 95 % CI = 0.66-0.98; Aa+aa vs. AA: OR = 0.79, 95 % CI = 0.65-0.96). Likewise, significant correlation between Bsm1, Taq1 polymorphism and LC risk was detected among Asians. Cdx-2 polymorphism was considered as a protective factor in Caucasians, whereas no association of Apal polymorphism with LC risk was observed in Asians and Caucasians for all genetic models.

Conclusion: The results of this meta-analysis suggested that Bsm1, Taq1 and Cdx-2 polymorphism may contribute to lung cancer susceptibility, more studies need be conducted to confirm in the future.

Meta-path Based Prioritization of Functional Drug Actions with Multi-Level Biological Networks

Functional drug actions refer to drug-affected GO terms. They aid in the investigation of drug effects that are therapeutic or adverse. Previous studies have utilized the linkage information between drugs and functions in molecular level biological networks. Since the current knowledge of molecular level mechanisms of biological functions is still limited, such previous studies were incomplete. We expected that the multi-level biological networks would allow us to more completely investigate the functional drug actions. We constructed multi-level biological networks with genes, GO terms, and diseases. Meta-paths were utilized to extract the features of each GO term. We trained 39 SVM models to prioritize the functional drug actions of the various 39 drugs. Through the multi-level networks, more functional drug actions were utilized for the 39 models and inferred by the models. Multi-level based features improved the performance of the models, and the average AUROC value in the cross-validation was 0.86. Moreover, 60% of the candidates were true.

Pharmacokinetic interaction of calcitriol with 20(S)-protopanaxadiol in mice: Determined by LC/MS analysis

The physiological and anti-cancer functions of vitamin D₃ are accomplished primarily via 1α,25-dihydroxyvitamin D₃ (calcitriol), whereas 20(S)-protopanaxadiol (aPPD) is a ginsenoside, which is isolated from Panax ginseng, with potential anti-cancer benefits. In the present study, we report a pharmacokinetic (PK) herb-nutrient interaction between calcitriol and aPPD in mice. A liquid chromatography mass spectrometry (LC/MS) method was developed using 4-phenyl-1,2,4-triazoline-3,5-dione derivatizing agent and we subsequently used the method to quantitate calcitriol in mouse serum. The limit of quantitation was 0.01 ng/ml which is approximately 100 fold lower than the previously reported assay from our laboratory. Calcitriol PK parameters were determined in non-tumor-bearing or C4-2 human prostate tumor-bearing nude mice following oral co-administration of calcitriol either alone or in combination with aPPD. Mice were pretreated with oral aPPD (70 mg/kg) or vehicle control twice daily for seven consecutive days, followed by a single oral dose of 4 μg/kg calcitriol alone or in combination with aPPD. Our PK results demonstrated that co-administration of calcitriol with aPPD (following pre-treatment with vehicle for seven days) resulted in a 35% increase in the area under the curve (AUC_{0-24 h}) and a 41% increase in the maximum serum concentration (Cmax) compared to the calcitriol only group. aPPD therefore significantly increased calcitriol serum exposure. We also saw a reduction in the time required to reach Cmax. In contrast, calcitriol PK in mice co-administered with calcitriol and aPPD as well as those pretreated seven consecutive days with aPPD was no different than that determined for the mice that received vehicle for seven days as pre-treatment. Co-administration of calcitriol with aPPD therefore could increase health benefits of vitamin D₃, however any increased risk of hypercalcemia, resulting from this combination approach, requires further investigation. Lastly, we surmise that a cytochrome P450 inhibition-based mechanism may contribute to the observed PK interaction.

The role of vitamin D in ovarian cancer: epidemiology, molecular mechanism and prevention

Vitamin D is a fat-soluble prohormone best known for its role in maintaining calcium homeostasis. Large numbers of epidemiological studies have shown that vitamin D plays an important role in cancer prevention by regulating cellular proliferation and metabolism. Studies of the cellular mechanism of vitamin D in ovarian cancer strongly suggest that it exhibits protective and antitumorigenic activities through genomic and nongenomic signal transduction pathways. These results indicate that vitamin D deficiency results in an increase in the risk of developing ovarian cancer and that vitamin supplements may potentially be an efficient way of preventing cancer. Consequently, this review describes the epidemiology, molecular mechanism and evidence linking vitamin D deficiency to ovarian cancer.

Vitamin D, DNA methylation, and breast cancer

BACKGROUND

Vitamin D has anticarcinogenic and immune-related properties and may protect against some diseases, including breast cancer. Vitamin D affects gene transcription and may influence DNA methylation.

METHODS

We studied the relationships between serum vitamin D, DNA methylation, and breast cancer using a case-cohort sample (1070 cases, 1277 in subcohort) of non-Hispanic white women. For our primary analysis, we used robust linear regression to examine the association between serum 25-hydroxyvitamin D (25(OH)D) and methylation within a random sample of the cohort ("subcohort"). We focused on 198 CpGs in or near seven vitamin D-related genes. For these 198 candidate CpG loci, we also examined how multiplicative interactions between methylation and 25(OH)D were associated with breast cancer risk. This was done using Cox proportional hazards models and the full case-cohort sample. We additionally conducted an exploratory epigenome-wide association study (EWAS) of the association between 25(OH)D and DNA methylation in the subcohort.

RESULTS

Of the CpGs in vitamin D-related genes, cg21201924 (RXRA) had the lowest p value for association with 25(OH)D (p = 0.0004). Twenty-two other candidate CpGs were associated with 25(OH)D (p < 0.05; RXRA, NADSYN1/DHCR7, GC, or CYP27B1). We observed an interaction between 25(OH)D and methylation at cg21201924 in relation to breast cancer risk (ratio of hazard ratios = 1.22, 95% confidence interval 1.10-1.34; p = 7 × 10-5), indicating a larger methylation-breast cancer hazard ratio in those with high serum 25(OH)D concentrations. We also observed statistically significant (p < 0.05) interactions for six other RXRA CpGs and CpGs in CYP24A1, CYP27B1, NADSYN1/DHCR7, and VDR. In the EWAS of the subcohort, 25(OH)D was associated (q < 0.05) with methylation at cg24350360 (EPHX1; p = 3.4 × 10-8), cg06177555 (SPN; p = 9.8 × 10-8), and cg13243168 (SMARCD2; p = 2.9 × 10-7).

CONCLUSIONS

25(OH)D concentrations were associated with DNA methylation of CpGs in several vitamin D-related genes, with potential links to immune function-related genes. Methylation of CpGs in vitamin D-related genes may interact with 25(OH)D to affect the risk of breast cancer.

Calcitriol and cancer therapy: A missed opportunity

The vitamin D receptor is expressed in most tissues of the body - and the cancers that arise from those tissues. The vitamin D signaling pathway is active in those tissues and cancers. This is at least consistent with the hypothesis that perturbing this signaling may have a favorable effect on the genesis and growth of cancers. Epidemiologic data indicate that vitamin D signaling may be important in the initiation and outcome of a number of types of cancer. Many studies have shown that calcitriol (1,25 dihydroxycholecalciferol) and other vitamin D compounds have antiproliferative, pro-apoptotic, anti-cell migration and antiangiogenic activity in a number of preclinical studies in many different cancer types. Unfortunately, the assessment of the activity of calcitriol or other vitamin D analogues in the treatment of cancer, as single agents or in combination with other anticancer agents has been stymied by the failure to adhere to commonly accepted principles of drug development and clinical trials conduct.

Vitamin D receptor activation reduces VCaP xenograft tumor growth and counteracts ERG activity despite induction of TMPRSS2:ERG

Whether vitamin D is chemopreventive and/or has potential therapeutically in prostate cancer is unresolved. One confounding factor is that many prostate cancers express a TMPRSS2:ERG fusion gene whose expression is increased both by androgens and by vitamin D receptor (VDR) activation. Two challenges that limit VDR agonist use clinically are hypercalcemia and the cooperation of VDR with ERG to hyper-induce the 1α,25-dihydroxyvitamin D3 metabolizing enzyme, CYP24A1, thus reducing VDR activity. Using the VCaP TMPRSS2:ERG positive cell line as a model, we found that a nonsecosteroidal CYP24A1 resistant VDR agonist, VDRM2, substantially reduces growth of xenograft tumors without inducing hypercalcemia. Utilizing next generation RNA sequencing, we found a very high overlap of 1,25D(OH)2D3 and VDRM2 regulated genes and by drawing upon previously published datasets to create an ERG signature, we found activation of VDR does not induce ERG activity above the already high basal levels present in VCaP cells. Moreover, we found VDR activation opposes 8 of the 10 most significant ERG regulated Hallmark gene set collection pathways from Gene Set Enrichment Analysis (GSEA). Thus, a CYP24A1 resistant VDR agonist may be beneficial for treatment of TMPRSS2:ERG positive prostate cancer; one negative consequence of TMPRSS2:ERG expression is inactivation of VDR signaling.

Effects of Vitamin D on Endometriosis-Related Pain: A Double-Blind Clinical Trial

Background

Endometriosis is a disabling disease of reproductive-age women. Dysmenorrhea, dyspareunia, and pelvic pain are the main symptoms of endometriosis. Its etiology is not clear. Endometriosis may have various causes, including vitamin D deficiency, but its effect is controversial.

Material/Methods

In this double-blind clinical trial, we enrolled patients with endometriosis diagnosed and treated by laparoscopy, with scores of at least 3 for of dysmenorrhea and/or pelvic pain at 8 weeks after surgical treatment. They were randomly prescribed vitamin D (50 000 IU weekly for 12 weeks) or placebo. Severity of pain in the 2 groups (placebo and treatment) was compared by VAS test at 24 weeks after surgical treatment.

Results

There were 19 patients in the vitamin D group and 20 in the placebo group. Baseline characteristics in the 2 groups were similar. Following the treatment with vitamin D or placebo, we did not find significant differences in severity of pelvic pain (p=0.24) and dysmenorrhea (p=0.45) between the 2 groups. Mean pelvic pain at 24 weeks after laparoscopy in the vitamin D group was 0.84±1.74 and in placebo group it was 0.68±1.70 (p=0.513). Mean dysmenorrhea was 2.10±2.33 in the vitamin D group and 2.73±2.84 in the placebo group (p=0.45).

Conclusions

After ablative surgery for endometriosis, vitamin D treatment did not have a significant effect in reducing dysmenorrhea and/or pelvic pain.

Relative Expression of 1,25-Dihydroxyvitamin D3 Receptor, Vitamin D 1α-Hydroxylase, Vitamin D 24-Hydroxylase, and Vitamin D 25-Hydroxylase in Endometriosis and Gynecologic Cancers

The authors demonstrate expression of the vitamin D receptor (VDR) and its hydroxylases in the endometrium and ovaries of women with and without endometriosis and endometrial or ovarian cancer. Immunohistochemistry showed strong staining of the VDR in endometriosis and endometrial cancer, with the most intense staining in epithelial cells. The VDR mRNA was significantly increased in patients with endometrial and ovarian cancer compared to the control group. There was a significantly higher 1 alpha-hydroxylase expression in the endometrium of patients with endometriosis compared to healthy controls. The observed differences in VDR and 1 alpha -hydroxylase mRNA levels were maintained at the protein level. The authors found no differences in 25-OH vitamin D levels between the serum of patients with endometriosis (25.7 +/- 2.1 ng/mL, n = 46) and healthy controls (22.6 +/- 2.0 ng/mL, n = 33, P = .31). They hypothesize that vitamin D might influence the local activity of immune cells and cytokines thought to play important pathogenic roles in the development and maintenance of endometriosis.

Regulation of the CCN genes by vitamin D: A possible adjuvant therapy in the treatment of cancer and fibrosis

The CCN family is composed of six cysteine-rich, modular, and conserved proteins whose functions span a variety of tissues and include cell proliferation, adhesion, angiogenesis, and wound healing. Roles for the CCN proteins throughout the entire body including the skin, kidney, brain, blood vessels, hematopoietic compartment and others, are continuously being elucidated. Likewise, an understanding of the regulation of this important gene family is constantly becoming clearer, through identification of transcription factors that directly activate, repress, or respond to upstream cell signaling pathways, as well as other forms of gene expression control. Vitamin D (1,25-dihydroxyvitamin D3 or calcitriol), a vitamin essential for numerous biological processes, acts as a potent gene expression modulator. The regulation of the CCN gene family members by calcitriol has been described in many contexts. Here, we provide a concise and thorough overview of what is known about calcitriol and its regulation of the CCN genes, and argue that its regulation is of physiological importance in a wide breadth of tissues in which CCN genes function. In addition, we highlight the effects of vitamin D on CCN gene expression in the setting of two common pathologic conditions, fibrosis and cancer, and propose that the therapeutic effects of vitamin D3 described in these disease states may in part be attributable to CCN gene modulation. As vitamin D is perfectly safe in a wide range of doses and already showing promise as an adjuvant therapeutic agent, a deeper understanding of its control of CCN gene expression may have profound implications in clinical management of disease.

Calcitriol and 20(S)-protopanaxadiol synergistically inhibit growth and induce apoptosis in human prostate cancer cells

The potential cancer preventive roles of calcitriol, the dihydroxylated metabolite of Vitamin D3, as well as 20(S)-protopanaxadiol (aPPD), the aglycone of the protopanaxadiol family of ginsenosides, have gained much attention in recent years for the prevention/treatment of prostate cancer (PCa). In the present study, we evaluated the anticancer and chemosensitization effects of calcitriol at clinically relevant concentrations and aPPD, either alone or in combination, in two well-characterized human PCa cell lines: androgen-sensitive non-metastatic LNCaP cells and androgen-independent metastatic C4-2 cells. The effects of the treatments on PCa cell viability and proliferation rates were evaluated by MTS and Brdu assays, respectively. Combination Indices (CI) and Dose Reduction Indices (DRI) were estimated to assess synergistic anticancer activity using Calcusyn software (Biosoft, Cambridge, UK). Then, we determined the potential Pharmacodynamic interaction mechanisms as follows: The protein expression levels of the genes those are known to control cell cycle (cyclin D1 and cdk2); apoptosis (Bcl-2, Bax, and Capspases 3), androgen receptor and Vitamin D receptors were examined upon combinational treatment. The cell viability assay data show that addition of 10nM calcitriol to aPPD significantly lowered its IC50 values from the range of 41-53μM to 13-23μM, in LNCaP and C4-2 prostate cancer cells. The cell proliferation rate was significantly lower for combination treatments compared to the cells treated with aPPD alone. Similarly, Western blot results indicate that aPPD significantly upregulated Vitamin D receptor (VDR) expression, while calcitriol further enhanced the ability of aPPD to induce pro-apoptotic BAX, increased cleaved caspase-3 and downregulate cdk2 protein levels. Thus, the pharmacodynamic interaction between aPPD and calcitriol in impacting growth inhibition and apoptosis appears to be synergistic in nature. In conclusion, calcitriol sensitizes PCa cells to aPPD-mediated anticancer effects by enhancing its ability to induce apoptosis and reduce cell proliferation, and this synergism may limit calcitriol toxicity by facilitating the use of lower calcitriol doses. The associated increase in VDR expression and calcitriol half-life may be mechanistically associated with this sensitization effect.

Calcitriol in Combination Therapy for Prostate Cancer: Pharmacokinetic and Pharmacodynamic Interactions

Epidemiological studies indicate that vitamin D insufficiency could have an etiological role in prostate cancer. In addition, calcitriol, used in combination with currently available drugs, has the potential to potentiate their anticancer effects or act synergistically by inhibiting distinct mechanisms involved in prostate cancer growth. Clinical data have not yet provided sufficient evidence to demonstrate benefit of vitamin D due to the limited and underpowered studies that have been published to date. Here, we review the preclinical and clinical studies that describe the activity of calcitriol, applied either alone or in combination and assessed the mechanistic basis of pharmacodynamic and pharmacokinetic interactions with calcitriol. Important considerations for calcitriol use in combination therapy with respect to safety and clinical outcomes have been discussed. Many of these combinations have therapeutic potential for the treatment of several cancer types and it is anticipated that future clinical research will put emphasis on well‑designed clinical trials to establish efficacy.

Vitamin D Signaling Modulators in Cancer Therapy

The antiproliferative and pro-apoptotic effects of 1α,25-dihydroxycholecalciferol (1,25(OH)2D3, 1,25D3, calcitriol) have been demonstrated in various tumor model systems in vitro and in vivo. However, limited antitumor effects of 1,25D3 have been observed in clinical trials. This may be attributed to a variety of factors including overexpression of the primary 1,25D3 degrading enzyme, CYP24A1, in tumors, which would lead to rapid local inactivation of 1,25D3. An alternative strategy for improving the antitumor activity of 1,25D3 involves the combination with a selective CYP24A1 inhibitor. The validity of this approach is supported by numerous preclinical investigations, which demonstrate that CYP24A1 inhibitors suppress 1,25D3 catabolism in tumor cells and increase the effects of 1,25D3 on gene expression and cell growth. Studies are now required to determine whether selective CYP24A1 inhibitors+1,25D3 can be used safely and effectively in patients. CYP24A1 inhibitors plus 1,25D3 can cause dose-limiting toxicity of vitamin D (hypercalcemia) in some patients. Dexamethasone significantly reduces 1,25D3-mediated hypercalcemia and enhances the antitumor activity of 1,25D3, increases VDR-ligand binding, and increases VDR protein expression. Efforts to dissect the mechanisms responsible for CYP24A1 overexpression and combinational effect of 1,25D3/dexamethasone in tumors are underway. Understanding the cross talk between vitamin D receptor (VDR) and glucocorticoid receptor (GR) signaling axes is of crucial importance to the design of new therapies that include 1,25D3 and dexamethasone. Insights gained from these studies are expected to yield novel strategies to improve the efficacy of 1,25D3 treatment.

Topical Vitamin D3Is Effective in Treating Senile Warts Possibly by Inducing Apoptosis

Vitamin D3 ointments containing active forms of vitamin D3 are widely used to treat inflammatory keratotic dermatoses such as psoriasis. Senile wart or seborrheic keratosis is a benign tumor which occurs mainly in the elderly. It has traditionally been treated with surgical procedures, freezing with liquid nitrogen, or laser therapy. We treated senile warts with topical vitamin D3 ointments (tacalcitol, calcipotriol or maxacalcitol). Out of 116 cases treated for 3 to 12 months, 35 (30.2%) showed complete disappearance or more than an 80% decrease in the volume of the tumor, 54 cases (46.6%) showed a decrease in the volume between 40 and 80%, and no remarkable changes or decreases of less than 40% were seen in 27 cases (23.3%). The tumors faded without any inflammatory changes such as erythema or swelling. An organ culture experiment using senile wart as a material with several concentrations of tacalcitol revealed that tacalcitol induced apoptosis in the tissue. On the other hand, only sporadic apoptotic cells were seen in the controls (p<0.001). Vitamin D3 may affect senile warts by inducing apoptosis. Clearance of senile warts, especially on exposed areas without pain, may improve the quality of life (QOL) of the elderly.

Phase I safety and pharmacodynamic of inecalcitol, a novel VDR agonist with docetaxel in metastatic castration-resistant prostate cancer patients

PURPOSE

We conducted a phase I multicenter trial in naïve metastatic castrate-resistant prostate cancer patients with escalating inecalcitol dosages, combined with docetaxel-based chemotherapy. Inecalcitol is a novel vitamin D receptor agonist with higher antiproliferative effects and a 100-fold lower hypercalcemic activity than calcitriol.

EXPERIMENTAL DESIGN

Safety and efficacy were evaluated in groups of three to six patients receiving inecalcitol during a 21-day cycle in combination with docetaxel (75 mg/m2 every 3 weeks) and oral prednisone (5 mg twice a day) up to six cycles. Primary endpoint was dose-limiting toxicity (DLT) defined as grade 3 hypercalcemia within the first cycle. Efficacy endpoint was ≥30% PSA decline within 3 months.

RESULTS

Eight dose levels (40-8,000 μg) were evaluated in 54 patients. DLT occurred in two of four patients receiving 8,000 μg/day after one and two weeks of inecalcitol. Calcemia normalized a few days after interruption of inecalcitol. Two other patients reached grade 2, and the dose level was reduced to 4,000 μg. After dose reduction, calcemia remained within normal range and grade 1 hypercalcemia. The maximum tolerated dose was 4,000 μg daily. Respectively, 85% and 76% of the patients had ≥30% PSA decline within 3 months and ≥50% PSA decline at any time during the study. Median time to PSA progression was 169 days.

CONCLUSION

High antiproliferative daily inecalcitol dose has been safely used in combination with docetaxel and shows encouraging PSA response (≥30% PSA response: 85%; ≥50% PSA response: 76%). A randomized phase II study is planned.

[Repairing the spinal cord with vitamin D: a promising strategy]

In 2014, a phase II randomised, double blind clinical trial assessing the efficacy of cholecalciferol (vitamin D3) in patients with a cervical trauma will be set up. This trial stems from previous studies showing that vitamin D supplementation improves functional recovery in rat models of peripheral or central nerve injury. In a first series of experiments, we used a rat model of peripheral nerve trauma to demonstrate the therapeutic efficiency of vitamin D. We first demonstrated that ergocalciferol (vitamin D2) increases the number and the diameter of newly formed axons and improves the response of metabosensitive fibers from tibialis muscle, in a model of transected peroneal nerve. Then, we compared vitamin D2 and vitamin D3 and observed that the latter is more efficient. At the dose of 500 IU/kg/day, vitamin D3 induces a dramatic functional recovery. We also demonstrated that vitamin D3 increases the number of preserved or newly formed axons in the proximal end, the mean axon diameter in the distal end, neurite myelination in both the distal and proximal ends as well as the expression of genes involved in axogenesis and myelination. In parallel, we assessed the therapeutic role of vitamin D on the central nervous system. In a first study, using a rat model of spinal cord compression at the T10 thoracic level, we delivered vitamin D3 (cholecalciferol) orally at the dose of 50 IU/kg/day or 200 IU/kg/day. When compared to control animals, vitamin D-treated rats displayed, three months after injury, a significant improvement of ventilatory frequency and a reduction of H reflex indicating functional improvements at three months post-injury. In a second study, we used a rat model of cervical hemisection (C2) with a higher dose of oral vitamin D3 (500 IU/kg/day) delivered weekly, during 12 weeks. We observed an improved locomotor recovery, a reduced spasticity and a significantly higher rate of axons crossing the lesion site in treated animals. However, it must be pointed out that the functional improvement is reduced when vitamin D is provided one week after the trauma.

The role of vitamin D in chronic obstructive pulmonary disease, asthma and other respiratory diseases

There has been growing interest in recent years in the extraosseous effects of vitamin D. In this article, we review the physiology of vitamin D, the physiopathological effects associated with vitamin D deficit and the available evidence on its etiopathogenic role in respiratory diseases. Given the pleiotropic actions of vitamin D, it is biologically plausible that the deficit of this vitamin could play a pathogenic role of in the development of various respiratory diseases. However, the many epidemiological studies that have shown an association between low vitamin D levels and a higher risk of developing various respiratory diseases or a poorer prognosis if they do appear, were unable to show causality. Post-hoc analyses of some clinical trials, particularly in chronic obstructive pulmonary disease (COPD) and asthma, appear to suggest that some patient subtypes may benefit from correction of a vitamin D deficit. In this respect, it would be interesting to determine if the interindividual differences found in the effect of vitamin D deficit and responses to correcting this deficit could be explained by the genetic variants involved in vitamin D metabolism. Ultimately, only appropriately designed clinical trials will determine whether 25-OHD supplements can prevent or improve the course of the various respiratory diseases in which an epidemiological association between prognosis and vitamin D deficit has been described.

26,26,26,27,27,27-Hexadeuterated-1,25-Dihydroxyvitamin D3 (1,25D-d6) As Adjuvant of Chemotherapy in Breast Cancer Cell Lines

It has been demonstrated that 1,25-dihydroxyvitamin D₃ (1,25D) and some of its analogues have antitumor activity. 1,25D labeled with deuterium (26,26,26,27,27,27-hexadeuterated 1α,25-dihydroxyvitamin D₃, or 1,25D-d₆) is commonly used as internal standard for 1,25D liquid chromatography-mass spectrometry (LC-MS) quantification. In the present study using human breast cancer cell lines, the biological activity of 1,25D-d₆ administered alone and in combination with two commonly used antineoplastic agents, 5-fluorouracil and etoposide, was evaluated. Using an MTT assay, flow cytometry, and western blots, our data demonstrated that 1,25D-d₆ has effects similar to the natural hormone on cell proliferation, cell cycle, and apoptosis. Furthermore, the combination of 1,25D-d₆ and etoposide enhances the antitumoral effects of both compounds. Interestingly, the antitumoral effect is higher in the more aggressive MDA-MB-231 breast cancer cell line. Our data indicate that 1,25D-d₆ administered alone or in combination with chemotherapy could be a good experimental method for accurately quantifying active 1,25D levels in cultures or in biological fluids, on both in vitro breast cancer cell lines and in vivo animal experimental models.

Vitamin D receptor gene polymorphisms in breast and renal cancer: current state and future approaches (review)

Cancer is a major health problem and cause of death worldwide that accounted for 7.6 million deaths in 2008, which is projected to continue rising with an estimated 13.1 million deaths in 2030 according to WHO. Breast cancer is the leading cause of cancer-based death among women around the world and its incidence is increasing annually with a similar tendency. In contrast, renal cell carcinoma accounts for only 3% of total human malignancies but it is still the most common type of urological cancer with a high prevalence in elderly men (>60 years of age). There are several factors linked with the development of renal cell cancer only, while others are connected only with breast cancer. Genetic risk factors and smoking are the factors which contribute to carcinogenesis in general. Some evidence exists indicating that vitamin D receptor (VDR) gene polymorphisms are associated with both breast and renal cancer; therefore, we put forward the hypothesis that polymorphisms in the VDR gene may influence both the occurrence risks of these cancers and their prognosis. However, the relationship between VDR polymorphisms and these two specific cancers remains a controversial hypothesis, and consequently needs further confirmation via clinical research together with genetic investigations. Here, we aimed to assess the correlation between the different alleles of VDR gene polymorphisms and renal cell cancer and breast cancer risks separately through a systematic review of the present literature. In contrast, this analysis has revealed that some VDR gene polymorphisms, such as: Bsm1, poly(A), Taq1, Apa1, are to some extent associated with breast cancer risk. Other polymorphisms were found to be significantly associated with renal cell cancer. Namely, they were Fok1, Bsm1, Taq1 and Apa1, which encode proteins participating mainly in proliferation, apoptosis and cell cycle regulation. However, data concerning renal cancer are not sufficient to firmly establish the VDR gene polymorphism association.

The Inverse Relationship between 25-Hydroxyvitamin D and Cancer Survival: Discussion of Causation

Cancer mortality rates vary inversely with geographic latitude and solar ultraviolet-B doses. This relationship may be due to an inhibitory role of vitamin D on cancer development. The relationship between vitamin D and cancer appears to be stronger for studies of cancer mortality than incidence. Because cancer mortality reflects both cancer incidence and survival, the difference may be due to effects of vitamin D on cancer survival. Here we review analytic epidemiologic studies investigating the relation between vitamin D, measured by circulating levels of 25-hydroxyvitamin D (25-OHD), and cancer survival. A relationship between low 25-OHD levels and poor survival is shown by most of the reviewed studies. This relationship is likely to be causal when viewed in light of most criteria for assessing causality (temporality, strength, exposure-response, biological plausibility and consistency). A serum level of 25-OHD around 50 nmol/L appears to be a threshold level. Conversely, there are several mechanisms whereby cancer could lower serum levels of 25-OHD. The severity of disease at the time of diagnosis and time of serum sampling are key factors to clarify the temporal aspect of these relationships. Evidence that vitamin D supplementation could retard the disease process or prolong survival time would be key evidence, but is difficult to generate. However, recent clinical trial results in prostate cancer support a role for vitamin D in this regard.

Anticancer steroids: linking natural and semi-synthetic compounds

Steroids, a widespread class of natural organic compounds occurring in animals, plants and fungi, have shown great therapeutic value for a broad array of pathologies. The present overview is focused on the anticancer activity of steroids, which is very representative of a rich structural molecular diversity and ability to interact with various biological targets and pathways. This review encompasses the most relevant discoveries on steroid anticancer drugs and leads through the last decade and comprises 668 references.

Vitamin d: pharmacokinetics and safety when used in conjunction with the pharmaceutical drugs used in cancer patients: a systematic review

Vitamin D has reported anti-cancer and anti-inflammatory properties modulated through gene transcription and non-genomic signaling cascades. The purpose of this review was to summarize the available research on interactions and pharmacokinetics between vitamin D and the pharmaceutical drugs used in patients with cancer. Hypercalcemia was the most frequently reported side effect that occurred in high dose calcitriol. The half-life of 25(OH)D₃ and/or 1,25(OH)₂D₃ was found to be impacted by cimetidine; rosuvastatin; prednisone and possibly some chemotherapy drugs. No unusual adverse effects in cancer patients; beyond what is expected from high dose 1,25(OH)₂D₃ supplementation, were revealed through this review. While sufficient evidence is lacking, supplementation with 1,25(OH)₂D₃ during chemotherapy appears to have a low risk of interaction. Further interactions with vitamin D₃ have not been studied.

A phase I/II pharmacokinetic and pharmacogenomic study of calcitriol in combination with cisplatin and docetaxel in advanced non-small-cell lung cancer

BACKGROUND

Preclinical studies demonstrated antiproliferative synergy of 1,25-D3 (calcitriol) with cisplatin. The goals of this phase I/II study were to determine the recommended phase II dose (RP2D) of 1,25-D3 with cisplatin and docetaxel and its efficacy in metastatic non-small-cell lung cancer.

METHODS

Patients were ≥18 years, PS 0-1 with normal organ function. In the phase I portion, patients received escalating doses of 1,25-D3 intravenously every 21 days prior to docetaxel 75 mg/m(2) and cisplatin 75 mg/m(2) using standard 3 + 3 design, targeting dose-limiting toxicity (DLT) rate <33 %. Dose levels of 1,25-D3 were 30, 45, 60, and 80 mcg/m(2). A two-stage design was employed for phase II portion. We correlated CYP24A1 tagSNPs with clinical outcome and 1,25-D3 pharmacokinetics (PK).

RESULTS

34 patients were enrolled. At 80 mcg/m(2), 2/4 patients had DLTs of grade 4 neutropenia. Hypercalcemia was not observed. The RP2D of 1,25-D3 was 60 mcg/m(2). Among 20 evaluable phase II patients, there were 2 confirmed, 4 unconfirmed partial responses (PR), and 9 stable disease (SD). Median time to progression was 5.8 months (95 % CI 3.4, 6.5), and median overall survival 8.7 months (95 % CI 7.6, 39.4). CYP24A1 SNP rs3787554 (C > T) correlated with disease progression (P = 0.03) and CYP24A1 SNP rs2762939 (C > G) trended toward PR/SD (P = 0.08). There was no association between 1,25-D3 PK and CYP24A1 SNPs.

CONCLUSIONS

The RP2D of 1,25-D3 with docetaxel and cisplatin was 60 mcg/m(2) every 21 days. Pre-specified endpoint of 50 % confirmed RR was not met in the phase II study. Functional SNPs in CYP24A1 may inform future studies individualizing 1,25-D3.

Sunlight may increase the FDG uptake value in primary tumors of patients with non-small cell lung cancer

Currently, positron emission tomography with computerized tomography (PET-CT) is the most sensitive technique for detecting extracranial metastases in non-small cell lung cancer (NSCLC). It has been reported that there is a correlation between the maximal standardized uptake value (SUV(max)) of primary tumors and prognosis in patients with NSCLC. The effect of sunlight exposure on PET-CT SUV(max) value is not known. Therefore, we aimed to evaluate the effect of sunlight exposure on PET-CT SUV(max) value in patients with NSCLC. A total of 290 patients with NSCLC from two different regions of Turkey (Kayseri, n=168 and Adana, n=122) that have different climate and sunlight exposure intensity, were included in the study. Age, gender, histology of cancer, cancer stage, smoking status, comorbidity and SUV(max) of the primary tumor area at the time of staging were evaluated as prognostic factors. In the multivariate analysis, we detected that the region was the only independent factor affecting SUV(max) (P=0.019). We identified that warmer climate and more sunlight exposure significantly increases the SUV(max) value of the primary tumor area in patients with NSCLC. Further studies are warranted to clarify the issue.

Inhibition of cancer growth and induction of apoptosis by BGP-13 and BGP-15, new calcipotriene-derived vitamin D3 analogs, in-vitro and in-vivo studies

One of the most innovative approaches to the treatment of cancer entails the use of 1α,25-dihydroxyvitamin D3 (calcitriol) analogs to inhibit cancer cell growth. We demonstrate here that BGP-13, a new calcipotriene-based 1α,25-dihydroxyvitamin D3 analog that we synthesized in our laboratory, inhibits the growth of prostate cancer (LNCaP), breast cancer (MCF-7), and colon cancer (HT-29) cell lines. Moreover, we also show that BGP-13 causes cells both to accumulate in G0-G1 and to activate caspase-3 and undergo apoptosis. In addition, we observed elevated vitamin D receptor (VDR) mRNA and protein levels in both LNCaP and MCF-7 cells following the exposure of the two cell lines to BGP-13. Importantly, we found that both the new analog BGP-13 and also BGP-15, another calcipotriene-based analog we synthesized previously and about which we published recently, inhibit the growth of HT-29 tumor xenografts in nude mice.

Vitamin D and cancer

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

The role of vitamin D in cancer prevention and treatment

Considerable data described in the first part of this review suggest that there is a role for vitamin D in cancer therapy and prevention. Although the preclinical data are persuasive and the epidemiologic data intriguing, no well-designed clinical trial of optimal administration of vitamin D as a cancer therapy has ever been conducted. Had there been the opportunity and insight to develop calcitriol as any other cancer drug, the following studies would have been completed: 1. Definition of the MTD. 2. Definition of a phase II dose, as a single agent and in combination with cytotoxic agents. 3. Studies to define a biologically optimal dose. 4. Phase II (probably randomized phase II) studies of calcitriol alone and chemotherapy ± calcitriol. 5. Then, randomized phase III trials would be conducted and designed such that the only variable was the administration of calcitriol. Prerequisites 1 to 5 have not been completed for calcitriol. Preclinical data provide considerable rationale for continued development of vitamin D analogue-based cancer therapies. However, design of future studies should be informed by good clinical trials design principles and the mistakes of the past not repeated. Such studies may finally provide compelling data to prove whether or not there is a role for vitamin D analogues in cancer therapy.

Serum levels of 25-hydroxyvitamin D and survival in Norwegian patients with cancer of breast, colon, lung, and lymphoma: a population-based study

PURPOSE

We investigated the association between serum levels of 25-hydroxyvitamin D (25-OHD) and risk of death in Norwegian cancer patients.

METHODS

The study population was 658 patients with cancers of the breast (n = 251), colon (n = 52), lung (n = 210), and lymphoma (n = 145), obtained from JANUS, a population-based serum bank in Norway. Serum samples were collected within 90 days of cancer diagnosis and were analyzed for 25-OHD. Patients were diagnosed during 1984-2004 and were followed for death throughout 2008. We used Cox regression models to assess the relationship between serum 25-OHD and risk of death.

RESULTS

Three hundred and ninety-nine patients died during follow-up, of whom 343 (86%) died from cancer. Adjusted for sex, age at diagnosis, and season of blood sampling, patients with 25-OHD levels below 46 nmol/L at diagnosis experienced shorter survival. Compared to patients in the lowest quartile of serum 25-OHD, the risk of cancer death among patients in the highest quartile was significantly reduced (HR 0.36 95% CI 0.27, 0.51). The estimated change in risk of cancer death was most pronounced between the first and the second quartile. The associations between 25-OHD levels and survival were observed for all four cancers.

CONCLUSIONS

Higher circulating serum levels of 25-OHD were positively associated with the survival for cancers of the breast, colon, lung, and lymphoma.