Unknown,Transcriptomics,Genomics,Proteomics

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Microarray analysis of gene expression of ovarian cancer cells treated with 1,25-dihydroxyvitamin D3

ABSTRACT: To profile the changes in the pattern of gene expression in human OCa cells induced by 1,25(OH)2D3, OVCAR3 cells were treated with 0.1 pM 1,25(OH)2D3 for 0, 8, 24 and 72 h. The cells were harvested, RNA was extracted, and Affmetrix microarrays were hybridized. OVCAR3 cells were treated with 0.1 pM 1,25(OH)2D3 for 0, 8, 24 and 72 hours. 1,25(OH)2D3 was added at different times to allow the treated cells to be harvested at the same time. Ethanol was included as vehicle controls and all cells were exposed to the same amount of ethanol for the same length of time. Total RNA was extracted using Trizol reagent (Invitrogen) and purified using Qiagen Rneasy kit as recommended by Affymetrix. In the initial set of array analysis with U95 chips, GADD45 was identified to be a VD-induced gene in OVCAR3 cells, which was confirmed by a follow-up study to be a primary target gene. For the array analyses with U133A chips, the response to 1,25(OH)2D3 of the cells used for RNA isolation was ensured by Northern blotting analysis of GADD45. Three independent experiments were performed.

ORGANISM(S): Homo sapiens

SUBMITTER: Xiaohui Zhang

PROVIDER: E-GEOD-26903 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:The biological effects of 1?,25-dihydroxyvitamin D3 (1,25(OH)2D3) on osteoblast differentiation and function differ significantly depending upon the cellular state of maturation. To explore this phenomenon mechanistically, we examined the impact of 1,25(OH)2D3 on the transcriptomes of both pre-osteoblastic (POBs) and differentiated osteoblastic (OBs) MC3T3-E1 cells, and assessed localization of the vitamin D receptor (VDR) at sites of action on a genome-scale using ChIP-seq analysis. We observed that the 1,25(OH)2D3-induced transcriptomes of POBs and OBs were quantitatively and qualitatively different, supporting not only the altered biology observed but the potential for a change in VDR interaction at the genome as well. This idea was confirmed through discovery that VDR cistromes in POBs and OBs were also strikingly different. Depletion of VDR binding sites in OBs, due in part to reduced VDR expression, was the likely cause of the loss of VDR-target gene interaction. Continued novel regulation by 1,25(OH)2D3, however, suggested that factors in addition to the VDR might also be involved. Accordingly, we show that transcriptomic modifications are also accompanied by changes in genome binding of the master osteoblast regulator RUNX2 and the chromatin remodeler C/EBP?. Importantly, genome occupancy was also highlighted by the presence of epigenetic enhancer signatures which were selectively changed in response to both differentiation and 1,25(OH)2D3. The impact of VDR, RUNX2, and C/EBP? on osteoblast differentiation is exemplified by their actions at the Runx2 and Sp7 gene loci. We conclude that each of these mechanisms may contribute to the diverse actions of 1,25(OH)2D3 on differentiating osteoblasts. 4 transcription factors and 5 histone modifications were examined in undifferentiated MC3T3-E1 cells as well as post 15 day osteogenic differentiation MC3T3-E1 cells, which were treated for 3 hours prior to ChIP assay with ethanol vehicle or with 10-7M 1,25(OH)2D3. For the vehicle matched samples for RUNX2, CEBP beta and histones, please refer to study GSE41955. The samples were completed in biological replicate and examined separately.