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1.  Demasculinization and feminization of male gonads by atrazine: Consistent effects across vertebrate classes 
Atrazine is the most commonly detected pesticide contaminant of ground water, surface water, and precipitation. Atrazine is also an endocrine disruptor that, among other effects, alters male reproductive tissues when animals are exposed during development. Here, we apply the nine so-called “Hill criteria” (Strength, Consistency, Specificity, Temporality, Biological Gradient, Plausibility, Coherence, Experiment, and Analogy) for establishing cause–effect relationships to examine the evidence for atrazine as an endocrine disruptor that demasculinizes and feminizes the gonads of male vertebrates. We present experimental evidence that the effects of atrazine on male development are consistent across all vertebrate classes examined and we present a state of the art summary of the mechanisms by which atrazine acts as an endocrine disruptor to produce these effects.
Atrazine demasculinizes male gonads producing testicular lesions associated with reduced germ cell numbers in teleost fish, amphibians, reptiles, and mammals, and induces partial and/or complete feminization in fish, amphibians, and reptiles. These effects are strong (statistically significant), consistent across vertebrate classes, and specific. Reductions in androgen levels and the induction of estrogen synthesis – demonstrated in fish, amphibians, reptiles, and mammals – represent plausible and coherent mechanisms that explain these effects. Biological gradients are observed in several of the cited studies, although threshold doses and patterns vary among species. Given that the effects on the male gonads described in all of these experimental studies occurred only after atrazine exposure, temporality is also met here. Thus the case for atrazine as an endocrine disruptor that demasculinizes and feminizes male vertebrates meets all nine of the “Hill criteria”.
PMCID: PMC4303243  PMID: 21419222
Atrazine; Gonads; Endocrine disruptor
2.  N-terminal domain of the androgen receptor contains a region that can promote cytoplasmic localization 
The Journal of steroid biochemistry and molecular biology  2013;139:10.1016/j.jsbmb.2013.09.013.
Nucleocytoplasmic trafficking of the androgen receptor (AR) represents an essential step in androgen action. To determine whether the amino-terminal domain (NTD) contains potential nuclear import and/or export signals, deletion mutants of the NTD tagged with green fluorescent protein (GFP) were generated and tested for their intracellular localization in both AR-negative and AR-positive cell lines. Subcellular localization analysis suggested a role of the NTD in regulating AR subcellular localization and revealed that the region of a.a. 50-250 of the NTD of AR (AR50-250) could promote cytoplasmic localization. Leptomycin B inhibited the activity of AR50-250, suggesting that AR50-250 export is mediated through exportin 1, either directly or indirectly. These observations argue for an important role of the NTD in regulating AR nucleocytoplasmic trafficking and will facilitate further investigation of interactions among different signals in regulating AR nucleocytoplasmic trafficking, which may lead to new approaches to inhibit AR nuclear localization.
PMCID: PMC3858452  PMID: 24099702
Androgen receptor; NTD; subcellular localization; AR50-250; Leptomycin B
3.  Vitamin D Deficiency in Reproductive Age Mongolian Women: A Cross Sectional Study 
Vitamin D production is critical not only for rickets prevention but for its role in several chronic diseases of adulthood. Maternal vitamin D status also has consequences for the developing fetus. This study assessed the prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D]<20 ng/ml) and insufficiency [25(OH)D = 20–29 ng/ml] in spring, among reproductive age Mongolian women.
Blood was drawn in March and April, 2009 from 420 Mongolian women, 18–44 years of age. Serum 25(OH)D concentrations were measured, anthropometric measurements were performed and information was collected by interview on lifestyle, dietary and reproductive factors. Logarithm-transformed 25(OH)D levels were compared across risk factor categories by analysis of variance. Linear regression analysis was used to assess the independent associations of factors with vitamin D status. Cutaneous vitamin D3 synthesis was assessed between December and July using a standard 7-dehydrocholesterol ampoule model.
The vast majority of women 415 (98.8%) had serum 25(OH)D <20 ng/ml (50 nmol/l) with an additional 4 women (<1%) in the insufficient range (20–29 ng/ml); only one women (0.2%) had sufficient levels (>30 ng/ml or 75 nmol/l). 25(OH)D concentrations were positively and independently associated with educational status and use of vitamin D supplements, but not with other demographic, lifestyle, reproductive, or anthropometric factors. 25(OH)D levels were not associated with dietary factors in this population, as there is little access to foods containing vitamin D in Mongolia. No production of previtamin D3 was observed until March and was maximally effective in April and was sustained through July.
These data suggest that the prevalence of vitamin D deficiency in spring among reproductive age women in Mongolia is high. Given the lack of naturally vitamin D-rich food in the diet and limited use of vitamin D supplements, food fortification and/or supplementation with vitamin D should be considered among these women.
PMCID: PMC3909713  PMID: 24076033
25-hydroxyvitamin D; vitamin D; vitamin D deficiency; healthy women; reproductive age
4.  Environmental Epigenetics and Phytoestrogen/Phytochemical Exposures 
The Journal of steroid biochemistry and molecular biology  2012;139:10.1016/j.jsbmb.2012.12.011.
One of the most important environmental factors to promote epigenetic alterations in an individual is nutrition and exposure to plant compounds. Phytoestrogens and other phytochemicals have dramatic effects on cellular signaling events, so have the capacity to dramatically alter developmental and physiological events. Epigenetics provides one of the more critical molecular mechanisms for environmental factors such as phytoestrogens/phytochemicals to influence biology. In the event these epigenetic mechanisms become heritable through epigenetic transgenerational mechanisms the impacts on the health of future generations and areas such as evolutionary biology need to be considered. The current review focuses on available information on the environmental epigenetics of phytoestrogen/phytochemical exposures, with impacts on health, disease and evolutionary biology considered.
PMCID: PMC3644519  PMID: 23274117
Epigenetics; Phytoestrogens; Phytochemicals; Transgenerational; Environmental Exposures; Review
5.  The human myometrium differentially expresses mTOR signalling components before and during pregnancy: evidence for regulation by progesterone 
The Journal of steroid biochemistry and molecular biology  2013;139:10.1016/j.jsbmb.2013.02.017.
Emerging studies implicate the signalling of the mammalian target of rapamycin (mTOR) in a number of reproductive functions. To this date, there are no data regarding the expression of mTOR signalling components in the human myometrium during pregnancy. We hypothesized that mTOR-related genes might be differentially expressed in term or preterm labour as well as in labour or non-labour myometria during pregnancy. Using quantitative RT-PCR we demonstrate for first time that there is a significant downregulation of mTOR, DEPTOR, and Raptor in preterm labouring myometria when compared to non-pregnant tissues taken from the same area (lower segment). We used an immortalised myometrial cell line (ULTR) as an in vitro model to dissect further mTOR signalling. In ULTR cells DEPTOR and Rictor had a cytoplasmic distribution, whereas mTOR and Raptor were detected in the cytoplasm and the nucleus, indicative of mTORC1 shuttling. Treatment with inflammatory cytokines caused only minor changes in gene expression of these components, whereas progesterone caused significant down-regulation. We performed a non-biased gene expression analysis of ULTR cells using Nimblegen human gene expression microarray (n=3), and selected genes were validated by quantitative RT-PCR in progesterone treated myometrial cells. Progesterone significantly down-regulated key components of the mTOR pathway. We conclude that the human myometrium differentially expresses mTOR signalling components and they can be regulated by progesterone.
PMCID: PMC3855612  PMID: 23541542
mTOR; myometrium; progesterone; preterm labour
6.  Human adrenal cells that express both 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) and cytochrome b5 (CYB5A) contribute to adrenal androstenedione production 
Androstenedione is one of several weak androgens produced in the human adrenal gland. 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) and cytochrome b5 (CYB5A) are both required for androstenedione production. However, previous studies demonstrated the expression of HSD3B2 within the zona glomerulosa (ZG) and fasciculata (ZF) but low levels in the zona reticularis. In contrast, CYB5A expression increases in the zona reticularis (ZR) in human adrenal glands. Although their colocalization has been reported in gonadal theca and Leydig cells this has not been studied in the human adrenal. Therefore, we immonolocalized HSD3B2 and CYB5A in normal human adrenal glands and first demonstrated their co-expression in the cortical cells located at the border between the ZF and ZR in normal human adrenal. Results of in vitro studies using the human adrenal H295R cells treated with the HSD3B2 inhibitor, trilostane, also demonstrated a markedly decreased androstenedione production. Decreasing CYB5A mRNA using its corresponding siRNA also resulted in significant inhibition of androstenedione production in the H295R cells. These findings together indicate that there are a group of cells co-expressing HSD3B2 and CYB5A with hybrid features of both ZF and ZR in human adrenal cortex, and these hybrid cortical cells may play an important role in androstenedione production in human adrenal gland.
PMCID: PMC4269365  PMID: 21185375
HSD3B2; CYB5A; androstenedione; adrenal gland
7.  1, 25 Dihydroxyvitamin D Regulation of Glucose Metabolism in Harvey-ras Transformed MCF10A Human Breast Epithelial Cells 
This study was designed to investigate the impact of 1,25 dihydroxyvitamin D (1,25(OH)2D) on glucose metabolism during early cancer progression. Untransformed and ras-oncogene transfected (ras) MCF10A human breast epithelial cells were employed to model early breast cancer progression. 1,25(OH)2D modified the response of the ras cells to glucose restriction, suggesting 1,25(OH)2D may reduce the ras cell glucose addiction noted in cancer cells. To understand the 1,25(OH)2D regulation of glucose metabolism, following four-day 1,25(OH)2D treatment, metabolite fluxes at the cell membrane were measured by a nanoprobe biosensor, [13C6]glucose flux by 13C-mass isotopomer distribution analysis of media metabolites, intracellular metabolite levels by NMR, and gene expression of related enzymes assessed. Treatment with 1,25(OH)2D reduced glycolysis as flux of glucose to 3-phosphoglycerate was reduced by 15% (P = 0.017) and 32% (P < 0.003) in MCF10A and ras cells respectively. In the ras cells, 1,25(OH)2D reduced lactate dehydrogenase activity by 15% (P < 0.05) with a concomitant 10% reduction in the flux of glucose to lactate (P = 0.006), and reduction in the level of intracellular lactate by 55% (P = 0.029). Treatment with 1,25(OH)2D reduced flux of glucose to acetyl-coA 24% (P = 0.002) and 41% (P < 0.001), and flux to oxaloacetate 34% (P = 0.003) and 33% (P = 0.027) in the MCF10A and ras cells, respectively, suggesting a reduction in tricarboxylic acid (TCA) cycle activity. The results suggest a novel mechanism involving the regulation of glucose metabolism by which 1,25(OH)2D may prevent breast cancer progression.
PMCID: PMC4009997  PMID: 23619337
vitamin D; cancer prevention; breast cancer; glucose; energy metabolism; ras; 1, 25 dihydroxyvitamin D
8.  TGFβ1 alters androgenic metabolites and hydroxysteroid dehydrogenase enzyme expression in human prostate reactive stromal primary cells: Is steroid metabolism altered by prostate reactive stromal microenvironment? 
The Journal of steroid biochemistry and molecular biology  2013;138:10.1016/j.jsbmb.2013.05.016.
The inflammatory tissue microenvironment can be an active promoter in preneoplastic cancer lesions. Altered steroid hormone metabolism as induced by the inflammatory microenvironment may contribute to epithelial cancer progression. Dehydroepiandrosterone sulfate (DHEAS) is the most abundant endogenous steroid hormone present in human serum and can be metabolized to DHEA, androgens and/or estrogens in peripheral tissues. We have previously reported that TGFβ1-induced reactive prostate stromal cells increase DHEA metabolism to active androgens and alter prostate cancer cell gene expression. While much of the focus on mechanisms of prostate cancer and steroid metabolism is in the epithelial cancer cells, this study focuses on TGFβ1-induced effects on DHEA metabolic pathways and enzymes in human prostate stromal cells. In DHEA-treated primary prostate stromal cells, TGFβ1 produced time- and dose-dependent increases in metabolism of DHEA to androstenedione and testosterone. Also TGFβ1-treated prostate stromal cells exhibited changes in the gene expression of enzymes involved in steroid metabolism including up-regulation of 3β hydroxysteroid dehydrogenase (HSD), and down-regulation of 17βHSD5, and 17βHSD2. These studies suggest that reactive prostate stroma and the inflammatory microenvironment may contribute to altered steroid metabolism and increased intratumoral androgens.
PMCID: PMC3839662  PMID: 23770322
TGFβ1; Reactive prostate stroma; Androstenedione; Testosterone; DHEA; Steroid metabolism
9.  Anti-apoptotic phenotypes of cholestan-3β,5α,6β-triol-resistant human cholangiocytes: characteristics contributing to the genesis of cholangiocarcinoma 
The Journal of steroid biochemistry and molecular biology  2013;138:10.1016/j.jsbmb.2013.08.004.
The oxysterols cholestan-3β, 5α, 6β-triol (Triol) and 3-keto-cholest-4-ene (3K4) are increased in Opisthorchis viverrini-associated hamster cholangiocarcinoma and induce DNA damage and apoptosis via a mitochondria-dependent mechanism in MMNK-1 human cholangiocytes. Based on these observations, we hypothesized that chronic exposure of cholangiocytes to these pathogenic oxysterols may allow a growth advantage to a subset of these cells through selection for resistance to apoptosis, thereby contributing to cholangiocarcinogenesis. To test this hypothesis, we cultured MMNK-1 cells long-term in the presence of Triol. Alteration in survival and apoptotic factors of Triol-exposed cells were examined. Cells cultured long-term in the presence of Triol were resistant to H2O2-induced apoptosis, and demonstrated an increase in the phosphorylation of p38-α, CREB, ERK1/2 and c-Jun. Elevations in the ratio of Bcl-2/Bax and in the protein levels of anti-apoptotic factors including cIAP2, clusterin, and survivin were detected. These results show that long-term exposure of MNNK-1 cells to low doses of Triol selects for kinase-signaling molecules with regulate resistance to apoptosis and thereby enhance cell survival. Clonal expansion of such apoptosis-resistant cells may contribute to the genesis of cholangiocarcinoma.
PMCID: PMC3825754  PMID: 23959098
Oxysterols; Cholestan-3β; 5α; 6β-triol; cholangiocarcinoma; apoptosis; MMNK-1 cells
10.  17β-Estradiol Increases Expression of the Oxidative Stress Response and DNA Repair Protein Apurinic Endonuclease (Ape1) in the Cerebral Cortex of Female Mice Following Hypoxia 
The Journal of steroid biochemistry and molecular biology  2013;138:10.1016/j.jsbmb.2013.07.007.
While it is well established that 17β-estradiol (E2) protects the rodent brain from ischemia-induced damage, it has been unclear how this neuroprotective effect is mediated. Interestingly, convincing evidence has also demonstrated that maintaining or increasing the expression of the oxidative stress response and DNA repair protein apurinic endonuclease 1 (Ape1) is instrumental in reducing ischemiainduced damage in the brain. Since E2 increases expression of the oxidative stress response proteins Cu/Zn superoxide dismutase and thioredoxin in the brain, we hypothesized that E2 may also increase Ape1 expression and that this E2-induced expression of Ape1 may help to mediate the neuroprotective effects of E2 in the brain. To test this hypothesis, we utilized three model systems including primary cortical neurons, brain slice cultures, and whole animals. Although estrogen receptor α and Ape1 were expressed in primary cortical neurons, E2 did not alter Ape1 expression in these cells. However, immunofluorescent staining and quantitative Western blot analysis demonstrated that estrogen receptor α and Ape1 were expressed in the nuclei of cortical neurons in brain slice cultures and that E2 increased Ape1 expression in the cerebral cortex of these cultures. Furthermore, Ape1 expression was increased and oxidative DNA damage was decreased in the cerebral cortices of ovariectomized female C57Bl/6J mice that had been treated with E2 and exposed to hypoxia. Taken together, our studies demonstrate that the neuronal microenvironment may be required for increased Ape1 expression and that E2 enhances expression of Ape1 and reduces oxidative DNA damage, which may in turn help to reduce ischemia-induced damage in the cerebral cortex and mediate the neuroprotective effects of E2.
PMCID: PMC3825811  PMID: 23907014
Apurinic endonuclease 1; estrogen; estrogen receptor; reactive oxygen species; neuroprotection; hypoxia
11.  Development, validation and application of a stable isotope dilution liquid chromatography electrospray ionization/selected reaction monitoring/mass spectrometry (SID-LC/ESI/SRM/MS) method for quantification of keto-androgens in human serum✩, ✩✩ 
The Journal of steroid biochemistry and molecular biology  2013;138:10.1016/j.jsbmb.2013.06.014.
Prostate cancer is the most frequently diagnosed form of cancer in males in the United States. The disease is androgen driven and the use of orchiectomy or chemical castration, known as androgen deprivation therapy (ADT) has been employed for the treatment of advanced prostate cancer for over 70 years. Agents such as GnRH agonists and non-steroidal androgen receptor antagonists are routinely used in the clinic, but eventually relapse occurs due to the emergence of castration-resistant prostate cancer. With the appreciation that androgen signaling still persists in these patients and the development of new therapies such as abiraterone and enzalutamide that further suppresses androgen synthesis or signaling, there is a renewed need for sensitive and specific methods to quantify androgen precursor and metabolite levels to assess drug efficacy. We describe the development, validation and application of a stable isotope dilution liquid chromatography electrospray ionization selected reaction monitoring mass spectrometry (SID-LC/ESI/SRM/MS) method for quantification of serum keto-androgens and their sulfate and glucuronide conjugates using Girard-T oxime derivatives. The method is robust down to 0.2–4 pg on column, depending on the androgen metabolite quantified, and can also quantify dehydroepiandrosterone sulfate (DHEA-S) in only 1 μL of serum. The clinical utility of this method was demonstrated by analyzing serum androgens from patients enrolled in a clinical trial assessing combinations of pharmacological agents to maximally suppress gonadal and adrenal androgens (Targeted Androgen Pathway Suppression, TAPS clinical trial). The method was validated by correlating the results obtained with a hydroxylamine derivatization procedure coupled with tandem mass spectrometry using selected reaction monitoring that was conducted in an independent laboratory.
PMCID: PMC3866616  PMID: 23851165
Prostate cancer; Androgen metabolome; Mass spectrometry
12.  Androgen (dihydrotestosterone) - mediated regulation of food intake and obesity in female mice 
To better understand how elevated androgen levels regulate food intake and obesity in females, we treated ovariectomized female mice with dihydrotestosterone (non-aromatazable androgen), measured food intake and body weight, and evaluated physiological changes in liver function, glucose tolerance, and leptin resistance.
Ovariectomized mice were treated with DHT or placebo. Mice were then fed a high fat diet under free-feeding or pair-feeding conditions for 3 months. We found that when DHT-treated ovariectomized mice had free access to food (free-feeding), they had increased food intake and higher body weight compared with control animals. These mice also had a significantly greater accumulation of fat in the liver and exhibited increased fasting glucose, impaired glucose tolerance, and resistance to leptin. However, when these mice were placed on a restricted diet and fed the same caloric amounts as controls (pair-feeding), their body weight increased at the same rate as control animals. This suggests that androgen regulates food intake through altered leptin sensitivity, and this increase of food intake could significantly contribute to an obesity phonotype.
In summary, we demonstrated a role for androgen in the regulation of food intake and weight gain in females using a mouse model. This model will be useful to further elucidate the roles of elevated androgen in females.
PMCID: PMC4130703  PMID: 23665441
Androgen; Dihydrotestosterone; Ovariectomized mice; Females; Obesity; Food intake
13.  Tumor Progression in the LPB-Tag Transgenic Model of Prostate Cancer is Altered by Vitamin D Receptor and Serum Testosterone Status 
Previous studies have suggested that 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) induces cell cycle arrest and/or apoptosis in prostate cancer cells in vitro, suggesting that vitamin D may be a useful adjuvant therapy for prostate cancer and a chemopreventive agent. Most epidemiological data however shows a weak link between serum 25(OH)D3 and risk of prostate cancer. To explore dichotomy we have compared tumor progression in the LPB-Tag model of prostate in VDR knock out (VDRKO) and wild type (VDRWT) mice. On the C57BL/6 background LPB-Tag tumors progress significantly more rapidly in the VDRKO mice. VDRKO tumors show significantly higher levels of cell proliferation than VDRWT tumors. In mice supplemented with testosterone to restore the serum levels to the normal range, these difference in tumor progression, and proliferation are abrogated, suggesting that there is considerable cross-talk between the androgen receptor (AR) and the vitamin D axis which is reflected in significant changes in steady state mRNA levels of the AR, PCNA, cdk2 survivin and IGFR1 and 2 genes. These alterations may explain the differences between the in vitro data and the epidemiological studies.
PMCID: PMC4211603  PMID: 20347977
14.  Role of proinflammatory cytokines on expression of vitamin D metabolism and target genes in colon cancer cells 
Interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFα) are proinflammatory cytokines that play a critical role in inflammatory bowel disease, as well as in colorectal tumorigenesis. We hypothesize that these cytokines modulate the expression and thus activity of the vitamin D system in colonic epithelial cells. We treated the colon cancer cell line COGA-1A for 6, 12, and 24 h with 1,25-dihydroxyvitamin D3 (1,25-D3), IL-6, TNFα, and with combinations of these compounds. Using quantitative RT-PCR, we analyzed mRNA expression of genes activating and catabolizing 1,25-D3 (1α-hydroxylase (CYP27B1), 24-hydroxylase (CYP24A1)), expression of several vitamin D target genes, as well as expression of cyclooxygenase 2 (COX-2) and 15-hydroxyprostaglandin dehydrogenase. As expected, treatment with 1,25-D3 resulted in an upregulation of CYP24A1, whereas expression of CYP27B1 was not affected. Treatment with TNFα and IL-6 led to decreased expression of the vitamin D activating enzyme CYP27B1. The strong inflammatory property of TNFα was mirrored by its activation of COX-2 and inhibition of prostaglandin E2 (PGE2) catabolism. Interestingly, expression of the calcium ion channel TRPV6 was markedly decreased by TNFα.
We conclude from these results that the presence of proinflammatory cytokines might impair activation of 1,25-D3, limiting its anti-inflammatory action.
This article is part of a Special Issue entitled ‘16th Vitamin D Workshop’.
PMCID: PMC4138205  PMID: 24120915
Vitamin D; Inflammation; TNFα; IL-6; CYP24A1; TRPV6
15.  Role of proinflammatory cytokines on expression of vitamin D metabolism and target genes in colon cancer cells☆ 
•TNFα decreases CYP27B1 mRNA expression.•TNFα inhibits transcription of the calcium ion channel TRPV6.•1,25-D3 inhibits TNFα-induced upregulation of COX-2.
Interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFα) are proinflammatory cytokines that play a critical role in inflammatory bowel disease, as well as in colorectal tumorigenesis. We hypothesize that these cytokines modulate the expression and thus activity of the vitamin D system in colonic epithelial cells. We treated the colon cancer cell line COGA-1A for 6, 12, and 24 h with 1,25-dihydroxyvitamin D3 (1,25-D3), IL-6, TNFα, and with combinations of these compounds. Using quantitative RT-PCR, we analyzed mRNA expression of genes activating and catabolizing 1,25-D3 (1α-hydroxylase (CYP27B1), 24-hydroxylase (CYP24A1)), expression of several vitamin D target genes, as well as expression of cyclooxygenase 2 (COX-2) and 15-hydroxyprostaglandin dehydrogenase. As expected, treatment with 1,25-D3 resulted in an upregulation of CYP24A1, whereas expression of CYP27B1 was not affected. Treatment with TNFα and IL-6 led to decreased expression of the vitamin D activating enzyme CYP27B1. The strong inflammatory property of TNFα was mirrored by its activation of COX-2 and inhibition of prostaglandin E2 (PGE2) catabolism. Interestingly, expression of the calcium ion channel TRPV6 was markedly decreased by TNFα.
We conclude from these results that the presence of proinflammatory cytokines might impair activation of 1,25-D3, limiting its anti-inflammatory action.
This article is part of a Special Issue entitled ‘16th Vitamin D Workshop’.
PMCID: PMC4138205  PMID: 24120915
IBD, inflammatory bowel disease; CYP24A1, 1,25-dihydroxyvitamin D3 24-hydroxylase; CYP27B1, 25-hydroxyvitamin D3 1α-hydroxylase; CYP3A4, cytochrome P450, family 3, subfamily A, polypeptide 4; TRPV6, transient receptor potential cation channel, subfamily V, member 6; IGFBP3, insulin-like growth factor binding protein 3; PGE2, prostaglandin E2; COX-2, cyclooxygenase-2; 15-PGDH, 15-hydroxyprostaglandin dehydrogenase; Vitamin D; Inflammation; TNFα; IL-6; CYP24A1; TRPV6
16.  The vitamin D system is deregulated in pancreatic diseases 
•During PDAC development CYP24A1 levels are reduced in the endocrine islets.•During malignant transformation pancreatic ducts accumulate CYP24A1 protein.•CYP24A1 expression correlates with VDR in CP patients, but not in PDAC patients.•CYP24A1 overexpressing tumors are highly proliferative.•CaSR and VDR are co-expressed in the endocrine cells of the islets.
The vitamin D system is deregulated during development and progression of several cancer types. Data on the expression of the vitamin D system in the diseased pancreas are missing. The aim of this study was to investigate the expression of the vitamin D receptor (VDR), 1,25-dihydroxyvitamin D3 24-hydroxylase (CYP24A1), and the calcium-sensing receptor (CaSR), a vitamin D target gene, in the different regions of the pancreas in patients with chronic pancreatitis (n = 6) and pancreatic ductal adenocarcinomas (PDAC) (n = 17). We analyzed the expression of these genes at mRNA and protein level with quantitative real-time RT-PCR and immunostaining. mRNA expression of CYP24A1 and VDR was significantly increased in tumors compared with the adjacent non-tumorous tissue (p < 0.01), while CaSR mRNA expression decreased. Both the VDR and the CaSR protein were highly expressed in the endocrine compared with the exocrine pancreas. In CP the CYP24A1 expression was highest in the endocrine pancreas, while in PDACs in the transformed ducts. In the PDAC patients CYP24A1 expression in the islets was significantly lower than in CP patients. Our data suggest that during ductal adenocarcinoma development the vitamin D system in the pancreas becomes deregulated on two levels: in the islets CYP24A1 expression decreases weakening the negative feedback regulation of the vitamin D-dependent insulin synthesis/secretion. In the transformed ducts CYP24A1 expression increases, impairing the antiproliferative effect of vitamin D in these cells.
PMCID: PMC4217145  PMID: 25090635
VDR, vitamin D receptor; CYP24A1, 1,25-dihydroxyvitamin D3 24-hydroxylase; CaSR, calcium-sensing receptor; 1,25(OH)2D3, 1,25-dihydroxyvitamin D3; CYP27B1, 25-hydroxyvitamin D3 1α-hydroxylase; VDRE, vitamin D response elements; PDAC, pancreatic ductal adenocarcinoma; CP, chronic pancreatitis; Vitamin D; CYP24A1; VDR; CaSR; Chronic pancreatitis; Pancreatic ductal adenocarcinoma; Pancreatic cancer
17.  Regulation of the calcium-sensing receptor expression by 1,25-dihydroxyvitamin D3, interleukin-6, and tumor necrosis factor alpha in colon cancer cells☆ 
•1,25 Dihydroxyvitamin D3 induces the expression of CaSR in Caco2/AQ and Coga1A cells.•TNFα is the main driver of CaSR expression in Coga1A.•In Caco2/AQ cells 1,25 dihydroxyvitamin D3 counteracts the action of TNFα and IL-6.
Anti-proliferative effects of calcium in the colon are mediated, at least in part, via the calcium-sensing receptor (CaSR), a vitamin D target gene. The expression of CaSR decreases during colorectal tumor progression and the mechanisms regulating its expression are poorly understood. The CaSR promoter harbors vitamin D elements responsive to 1,25-dihydroxyvitamin D3 (1,25D3) and NF-κB, STAT, and SP1 binding sites accounting for responsiveness to proinflammatory cytokines. Therefore, in the current study we investigated the impact of 1,25D3, tumor necrosis factor alpha (TNFα), and interleukin (IL)-6 on CaSR expression in a differentiated (Caco2/AQ) and in a moderately differentiated (Coga1A) colon cancer cell line. 1,25D3 induced CaSR expression in both cell lines. Treatment with TNFα was accompanied by a 134-fold induction of CaSR in Coga1A (p < 0.01). In Caco2/AQ cells the expression of CaSR was upregulated also by IL-6 (3.5-fold). Our data demonstrated transcriptional and translational activation of the CaSR by 1,25D3, TNFα, and IL-6 in a time- and cell line-dependent manner.
This article is part of a Special Issue entitled ‘16th Vitamin D Workshop’.
PMCID: PMC4220008  PMID: 24176760
Calcium-sensing receptor; Colon cancer; Tumor necrosis factor alpha; Interleukin-6; 1,25-dihydroxyvitamin D3; Inflammation
18.  AKR1C3 as a Target in Castrate Resistant Prostate Cancer 
Aberrant androgen receptor (AR) activation is the major driver of castrate resistant prostate cancer (CRPC). CRPC is ultimately fatal and more therapeutic agents are needed to treat this disease. Compounds that target the androgen axis by inhibiting androgen biosynthesis and or AR signaling are potential candidates for use in CRPC treatment and are currently being pursued aggressively. Aldo-keto reductase 1C3 (AKR1C3) plays a pivotal role in androgen biosynthesis within the prostate. It catalyzes the 17-ketoreduction of weak androgen precursors to give testosterone and 5α-dihydrotestosterone. AKR1C3 expression and activity has been implicated in the development of CRPC, making it a rational target. Selective inhibition of AKR1C3 will be important however, due to the presence of closely related isoforms, AKR1C1 and AKR1C2 that are also involved in androgen inactivation. We examine the evidence that supports the vital role of AKR1C3 in CRPC and recent developments in the discovery of potent and selective AKR1C3 inhibitors.
PMCID: PMC3805777  PMID: 23748150
Type 5 17β-hydroxysteroid dehydrogenase; prostaglandin F synthase; prostate cancer; androgens; nonsteroidal anti-inflammatory drugs
19.  Steroidogenesis in the skin: implications for local immune functions 
The skin has developed a hierarchy of systems that encompasses the skin immune and local steroidogenic activities in order to protect the body against the external environment and biological factors and to maintain local homeostasis. Most recently it has been established that skin cells contain the entire biochemical apparatus necessary for production of glucocorticoids, androgens and estrogens either from precursors of systemic origin or, alternatively, through the conversion of cholesterol to pregnenolone and its subsequent transformation to biologically active steroids. Examples of these products are corticosterone, cortisol, testosterone, dihydrotesterone and estradiol. Their local production can be regulated by locally produced corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) or cytokines. Furthermore the production of glucocorticoids is affected by ultraviolet B radiation. The level of production and nature of the final steroid products are dependent on the cell type or cutaneous compartment, e.g., epidermis, dermis, adnexal structures or adipose tissue. Locally produced glucocorticoids, androgens and estrogens affect functions of the epidermis and adnexal structures as well as local immune activity. Malfunction of these steroidogenic activities can lead to inflammatory disorders or autoimmune diseases. The cutaneous steroidogenic system can also have systemic effects, which are emphasized by significant skin contribution to circulating androgens and/or estrogens. Furthermore, local activity of CYP11A1 can produce novel 7 -steroids and secosteroids that are biologically active. Therefore, modulation of local steroidogenic activity may serve as a new therapeutic approach for treatment of inflammatory disorders, autoimmune processes or other skin disorders. In conclusion, the skin can be defined as an independent steroidogenic organ, whose activity can affect its functions and the development of local or systemic inflammatory or autoimmune diseases.
PMCID: PMC3674137  PMID: 23435015
Glucocorticoids; androgen; estrogen; CYP11A1; skin endocrine system; skin immune system
We have explored the mechanism(s) underlying 1,25 dihydroxyvitamin D’s (1,25(OH)2D) suppression of agonist-induced vascular smooth muscle cells (VSMC) proliferation. Quiescent cultured adult rat VSMC were treated with 1,25(OH)2D for 48 hours and endothelin (ET) or angiotensin II (AII) for the final 24 hours. We show that VSMC responded to 1,25(OH)2D or its less hypercalcemic analogue RO 25-6760 with ~70% inhibition of ET-dependent 3H-thymidine incorporation. The inhibition was linked to a comparable reduction in ET-stimulated cyclin dependent kinase 2 (Cdk2) activity and suppression of an ET-induced Cdk2 activator, cell division cycle 25 homolog A (Cdc25A). Both 1,25(OH)2D and RO 25-6760 completely inhibited the ET-dependent increase in Cdc25A mRNA and protein levels, phosphatase and promoter activities. 1,25(OH)2D also suppressed AII-induced DNA synthesis, Cdk2 activity and Cdc25A gene transcription. Inhibition of Cdc25A gene expression using a siRNA approach resulted in significant inhibition of ET or AII-dependent Cdk2 activity and 3H-thymidine incorporation. The Cdc25A siRNA-mediated inhibition of ET or AII-induced Cdk2 activity and DNA synthesis was not additive with that produced by 1,25(OH)2D treatment. These data demonstrate that 1,25(OH)2D inhibits VSMC proliferation through a Cdc25A-dependent mechanism and suggest that this hormone may prove useful in the management of disorders characterized by aberrant proliferation of VSMC in the vascular wall.
PMCID: PMC4143149  PMID: 20813185
vitamin D; endothelin; Cdk2; Cdc25A; vascular smooth muscle cell
21.  The 1,25-dihydroxyvitamin D3-independent actions of the vitamin D receptor in skin 
The vitamin D endocrine system plays important but poorly understood roles in the skin and in hair follicle cycling. Rare, human genetic disorders and knockout mouse models highlight essential roles and potentially novel mechanisms of the vitamin D endocrine system in the skin. Vitamin D receptor knockout mice express a hair follicle cycling defect and a hyperproliferative phenotype resulting in disordered skin structure, epidermal thickening, and alopecia. In contrast, ligand knockout mice (i.e., mice with a disrupted CYP27B1 gene that encodes the 25-hydroxyvitamin-D3 1α-hydroxylase) have normal hair follicle function and a comparatively modest skin phenotype. These disparate models indicate that VDR may function independently of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in regulating hair follicle cycling and skin biology. Recent studies highlight this concept and provide key support for this hypothesis. While VDR knockout mice are highly susceptible to chemically-induced skin tumorigenesis, CYP27B1 knockouts are resistant. These studies reveal a second global physiological process in the skin that may be regulated by VDR in a 1,25(OH)2D3-independent fashion, namely, genoprotection against carcinogenic mutagens. Key cellular and molecular data supporting this mechanism were published recently showing a keratinocyte-selective transactivation activity mediated by VDR that is independent of the 1,25(OH)2D3 ligand. Thus, evidence is building to support a potentially novel, 1,25(OH)2D3-independent mechanism through which VDR functions in keratinocytes and perhaps within stem cell populations in the follicle to regulate genoprotection and other key developmental processes in the skin.
PMCID: PMC4127032  PMID: 20362670
vitamin D receptor; skin carcinogenesis; keratinocyte; cholecalciferol; transcription regulation
22.  1α,25(OH)2-Dihydroxyvitamin D3/VDR protects the skin from UVB-induced tumor formation by interacting with the β-catenin pathway 
Ultra violet (UV) irradiation, in particular UVB, is the single most important carcinogen for skin tumor formation. UVB induces genetic mutations and immune suppression, which lead to abnormal cell proliferation and eventually tumor formation. Previously studies from our group and others demonstrated that both global and epidermal specific VDR knock out mice are predisposed to either chemical (DMBA)-or long-term UVB-induced skin tumor formation, paralleled by an increase in β-catenin signaling. Using primary cultured human keratinocytes, we further demonstrated that 1,25(OH)2-dihydroxyvitamin D3 (1,25(OH)2D3) suppresses cyclin D1 and Gli1 which are regulated by β-catenin/TCF signaling and have a critical role in epidermal carcinogenesis. Blockage of VDR by siRNA resulted in hyperproliferation of keratinocytes, and increased expression of cyclin D1 and Gli1. In addition, we also showed that 1,25(OH)2D3/VDR directly regulates transcriptional activity of β-catenin/TCF signaling using the –catenin reporter TopGlow. Using K14 driven tamoxifen-induced cre recombinase to delete both VDR and β-catenin in keratinocytes of mice following the first hair follicle cycle, we found that ablation of epidermal specific β-catenin cannot rescue VDR null mice from UVB-induced skin tumor formation. Further study using VDR or β-catenin single null mice is necessary to compare with the data from double null mice.
PMCID: PMC4102608  PMID: 23026511
UVB; Wnt/β-catenin; Skin tumor
23.  Fifteenth Vitamin D Workshop 
PMCID: PMC4102609  PMID: 23768771
24.  Antiestrogenic Activity of Flavonoid Phytochemicals Mediated via the c-Jun N-terminal Protein Kinase Pathway 
Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling independent of direct receptor binding. Here we demonstrate both chalcone and flavone function as cell type-specific selective ER modulators. In MCF-7 breast carcinoma cells chalcone and flavone suppress ERα activity through stimulation of the stress-activated members of the mitogen-activated protein kinase (MAPK) family: c-Jun N-terminal kinase (JNK)1 and JNK2. The use of dominant-negative mutants of JNK1 or JNK2 in stable transfected cells established that the antiestrogenic effects of chalcone and flavone required intact JNK signaling. We further show that constitutive activation of the JNK pathway partially suppresses estrogen (E2)-mediated gene expression in breast, but not endometrial carcinoma cells. Our results demonstrate a role for stress-activated MAPKs in the cell type-specific regulation of ERα function.
PMCID: PMC4083692  PMID: 22634477
flavonoids; phytoestrogens; estrogen receptor; mitogen-activated protein kinase; antiestrogens; c-Jun N-terminal kinase (JNK)
25.  Vitamin D Metabolism and Action in Human Marrow Stromal Cells: Effects of Chronic Kidney Disease 
Human marrow stromal cells (hMSCs) are targets of 1! ,25-dihydroxyvitamin D [1! ,25(OH)2D3] action to promote their differentiation to osteoblasts, but they also participate in vitamin D metabolism by converting 25-dihydroxyvitamin D3 [25(OH)D3] to 1! ,25(OH)2D3 by 1α-hydroxylase (CYP27B1). Chronic kidney disease (CKD) is associated with impaired renal biosynthesis of 1! ,25(OH)2D, low bone mass, and increased fracture risk. We tested whether CKD influences hMSCs' responses to vitamin D3 metabolites. The hMSCs were obtained from tissues discarded during arthroplasty for hip osteoarthrosis, including a subject who had been undergoing hemodialysis for 2+ years. There was a significant positive correlation between in vitro stimulation of osteoblastogenesis (alkaline phosphatase activity) by 1! ,25(OH)2D3 and subjects' estimated glomerular filtration rate (eGFR, r=0.47, p=0.015, n=26, 56–83 years of age). Osteoblastogenesis was stimulated in hMSCs from both the hemodialysis and control subjects by 1! ,25(OH)2D3 (10 ! M), 25(OH)D3 (100 ! M), or D3 (1000 ! M). Thus, vitamin D metabolism may play an autocrine/paracrine role in osteoblast differentiation of hMSCs. These findings suggest that in CKD patients 25(OH)D-sufficiency may play an important role in skeletal health; osteoblastic bone formation in CKD patients may not be optimal unless there is sufficient serum 25(OH)D substrate for the MSCs to synthesize and respond to local 1! ,25(OH)2D.
PMCID: PMC3535685  PMID: 22989482
Human Marrow Stromal Cells; Osteoblastogenesis; Chronic Kidney Disease; eGFR; vitamin D metabolites

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