Project description:Human testicular cells were isolated mechanically and enzymatically from testis of braindead donors and from urological samples. The expression of genes was studied at baseline and 1,25(OH)2D treated conditions. We used microarrays to analyze the gene expression underlying vitamin D metabolism in human testis cells and identified distinct classes of up-regulated genes during this process. Testicular primary cells were treated with 100nM 1,25(OH)2D for 24h and gene expression studied by microarray on transcript level.
Project description:Human testicular cells were isolated mechanically and enzymatically from testis of braindead donors and from urological samples. The expression of genes was studied at baseline and 1,25(OH)2D treated conditions. We used microarrays to analyze the gene expression underlying vitamin D metabolism in human testis cells and identified distinct classes of up-regulated genes during this process.
Project description:Heterogeneous nuclear ribonucleoprotein C1/C2 (hnRNPC1/C2) functions as an RNA splicing regulator through co-transcriptional association with nascent mRNA. HnRNPC1/C2 can also bind to double-stranded DNA as a vitamin D response element-binding protein (VDRE-BP), thereby regulating transcriptional activity of the vitamin D receptor (VDR) bound to 1,25-dihydroxyvitamin D (1,25(OH)2D). In this way hnRNPC1/C2 may act as a coupling factor for 1,25(OH)2D-directed transcription and RNA splicing. Studies using MG63 osteoblastic cells confirmed that 1,25(OH)2D-VDR mediated induction of the gene for the enzyme 24-hydroxylase (CYP24A1), involved CYP24A1-specific chromatin and RNA immunoprecipitation of hnRNPC1/C2. Furthermore, small interfering (siRNA) knockdown of hnRNPC1/C2 in MG63 cells and was associated with dysregulated expression of CYP24A1 and an alternatively spliced form of CYP24A1 (CYP24A1-variant 2). Genome-wide analysis of RNA expression and alternative splicing indicated that dual role of hnRNPC1/C2 in directing 1,25(OH)2D-mediated gene expression is not restricted to the classical VDR-target CYP24A1. Knockdown of hnRNPC1/C2 resulted in 3500 differentially expressed genes (DEG), and treatment with 1,25(OH)2D 324 DEG. A further 87 DEG were only observed in 1,25(OH)2D-treated cells in hnRNPC1/C2 knockdown cells. HnRNPC1/C2 knockdown or 1,25(OH)2D treatment also induced alternative splicing (AS) (5039 and 310 AS events respectively). Combined hnRNPC1/C2 knockdown and 1,25(OH)2D treatment resulted in significant overlap between DEG and AS genes, but this was not observed for 1,25(OH)2D treatment alone. These data indicate that hnRNPC1/C2 can act to couple transcriptional and splicing responses to 1,25(OH)2D by binding to both DNA and RNA. Similar mechanisms may also exist for other members of the hnRNP and steroid receptor family.
Project description:Vitamin D is a pro-hormone that possesses various anticancer effects through diverse mechanisms. The enzyme vitamin D-25-hydroxylase can convert vitamin D into 25-hydroxyvitamin D (25(OH)D) in the liver. 25(OH)D serves as the precursor of 1,25-dihydroxyvitamin D (1,25(OH)2D or calcitriol), which can be transformed into 1,25(OH)2D by the enzyme CYP27B1. CYP27B1 is primarily distributed in the kidneys but can also be found in other tissues, such as the breast and colon. Although 1,25-dihydroxyvitamin D has been the primary object of in vitro studies, emerging evidence suggests that 25(OH)D can also generate anticancer effects by transforming into 1,25(OH)2D in the manner of autocrine and paracrine. Our study aims to investigate the impact of 25(OH)D on breast cancer and its effect on the expression of small RNA in breast cancer cells cultured with 100nM 25(OH)D.
Project description:Vitamin D as a pro-hormone is known to generate anticancer effects by various mechanisms. Vitamin D can be converted to 25-hydroxyvitamin D(25(OH)D) by the enzyme vitamin D-25-hydroxylase in the liver.25(OH)D is the precursor of 1,25‑dihydroxyvitamin D(1,25(OH)2D, also called calcitriol) and can be transformed by the enzyme CYP27B1. The distribution of CYP27B1 is mainly in the kidney, but also in other tissues like breast and colon. So far, research about the anticancer effects of Vitamin D mainly chooses 1,25‑dihydroxyvitamin D as the study object in vitro. However, there is increasing evidence showing that 25(OH)D also can generate anticancer effects by transforming into 1,25(OH)2D in the manner of autocrine and paracrine. Our study aims to explore the influence of 25(OH)D on breast cancer and provides the variation on the expression of RNA in the breast cancer cells cultured with 100nM 25(OH)D.
Project description:Heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2 plays a pivotal role in vitamin D receptor (VDR) signaling by acting as a vitamin D response element (VDRE)-binding protein (VDRE-BP). Transcriptional regulation by active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) involves occupancy of VDRE by VDRE-BP or 1,25(OH)2D3 bound-VDR. This relationship is disrupted by over-expression of VDRE-BP and can cause a form of human hereditary vitamin D-resistant rickets (HVDRR). DNA array analyses using B-cells from an HVDRR patient and matched control defined a sub-cluster of genes where 1,25(OH)2D3-regulated transcription was abrogated by over-expression of VDRE-BP. Amongst these, the DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling, was also induced by 1,25(OH)2D3 in human osteoblasts. Chromatin immunoprecipitation using 1,25(OH)2D3-treated osteoblasts confirmed that liganded VDR and VDRE-BP compete for binding to the proximal promoter of the DDIT4 gene in a similar fashion to other known 1,25(OH)2D3-target genes. Treatment of osteoblasts with 1,25(OH)2D3 induced DDIT4 expression and suppressed phosphorylated S6K1T389 protein (a downstream target of mTOR). The functional importance of this for 1,25(OH)2D3 responses in osteoblasts was underlined by the fact that siRNA knockdown of DDIT4 expression suppressed antiproliferative and cell growth responses to 1,25(OH)2D3. These data confirm that VDRE-BP is required for normal 1,25(OH)2D3-mediated transcription and cell function in osteoblasts. Conversely over-expression of VDRE-BP exerts a dominant-negative effect on transcription of 1,25(OH)2D3-target genes. Characterization of VDRE-BP action in 1,25(OH)2D3-treated osteoblasts highlights an entirely novel role for vitamin D as a regulator of mTOR – a known ‘master regulator’ of cell function.
Project description:Heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2 plays a pivotal role in vitamin D receptor (VDR) signaling by acting as a vitamin D response element (VDRE)-binding protein (VDRE-BP). Transcriptional regulation by active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) involves occupancy of VDRE by VDRE-BP or 1,25(OH)2D3 bound-VDR. This relationship is disrupted by over-expression of VDRE-BP and can cause a form of human hereditary vitamin D-resistant rickets (HVDRR). DNA array analyses using B-cells from an HVDRR patient and matched control defined a sub-cluster of genes where 1,25(OH)2D3-regulated transcription was abrogated by over-expression of VDRE-BP. Amongst these, the DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling, was also induced by 1,25(OH)2D3 in human osteoblasts. Chromatin immunoprecipitation using 1,25(OH)2D3-treated osteoblasts confirmed that liganded VDR and VDRE-BP compete for binding to the proximal promoter of the DDIT4 gene in a similar fashion to other known 1,25(OH)2D3-target genes. Treatment of osteoblasts with 1,25(OH)2D3 induced DDIT4 expression and suppressed phosphorylated S6K1T389 protein (a downstream target of mTOR). The functional importance of this for 1,25(OH)2D3 responses in osteoblasts was underlined by the fact that siRNA knockdown of DDIT4 expression suppressed antiproliferative and cell growth responses to 1,25(OH)2D3. These data confirm that VDRE-BP is required for normal 1,25(OH)2D3-mediated transcription and cell function in osteoblasts. Conversely over-expression of VDRE-BP exerts a dominant-negative effect on transcription of 1,25(OH)2D3-target genes. Characterization of VDRE-BP action in 1,25(OH)2D3-treated osteoblasts highlights an entirely novel role for vitamin D as a regulator of mTOR – a known ‘master regulator’ of cell function. We performed gene expression microarray analysis in HVDRR EBV-transformed B-cells and control cells in the presence or absence of vitamin D.
Project description:Background: Prostate cancer is the second leading cause of cancer mortality among US men. Epidemiological evidence suggests that high vitamin D status protects men from prostate cancer and the active form of vitamin D, 1α,25 dihydroxyvitamin D3 (1,25(OH)2D) has anti-cancer effects in cultured prostate cells. Still, the molecular mechanisms and the gene targets for vitamin D-mediated prostate cancer prevention are unknown. Results: We examined the effect of 1,25(OH)2D (+/- 100 nM, 6, 24, 48 h) on the transcript profile of proliferating RWPE1 cells, an immortalized, non-tumorigenic prostate epithelial cell line that is growth arrested by 1,25(OH)2D (Affymetrix U133 Plus 2.0, n=4/treatment per time and dose). Our analysis revealed many transcript level changes at a 5% false detection rate: 6 h, 1571 (61% up), 24 h, 1816 (60 % up), 48 h, 3566 (38 % up). 288 transcripts were regulated similarly at all time points (182 up, 80 down) and many of the promoters for these transcripts contained putative vitamin D response elements. Functional analysis by pathway or Gene Set Analysis revealed early suppression of WNT, Notch, NF-kB, and IGF1 signaling. Transcripts related to inflammation were suppressed at 6 h (e.g. IL-1 pathway) and suppression of proinflammatory pathways continued at later time points (e.g. IL-17 and IL-6 pathways). There was also evidence for induction of anti-angiogenic pathways and induction of transcripts for protection from oxidative stress or maintenance of cell redox homeostasis at 6 h. Conclusions: Our data reveal of large number of potential new, direct vitamin D target genes relevant to prostate cancer prevention. In addition, our data suggests that rather than having a single strong regulatory effect, vitamin D orchestrates a pattern of changes within prostate epithelial cells that limit or slow carcinogenesis. Experiment Overall Design: RWPE1 cells were treated with medium containing 100 nM of 1,25(OH)2D or vehicle (0.1% ethanol) for 6, 24 or 48 hours (n=4 per treatment, 24 total samples). The transcripts levels in each sample were measured by using the Affymetrix HU133 plus 2.0 GeneChip (Affymetrix, Santa Clara, CA).