Project description:To investigate the role of miRNA in the placental development, we analyzed miRNA expression profiles in the first and third trimester human placentas. Total RNA was isolated from 12 placentas (6 from first trimester and 6 from third trimester). miRNA expression profiles were determined by Affymetrix GeneChip 2.0 miRNA Microarray. Using miRNA microarray to determine miRNA expression profiles in the human placenta between first and third trimester pregnancies.
Project description:Background: the human placenta facilitates the exchange of nutrients, gas and waste between the fetal and maternal circulations. It also protects the fetus from the maternal immune response. Due to its role at the feto-maternal interface, the placenta is subject to many environmental exposures that can potentially alter its epigenetic profile. Previous studies have reported gene expression differences in placenta over gestation, as well as inter-individual variation in expression of some genes. However, the factors contributing to this variation in gene expression remain poorly understood. Results: in this study, we performed a genome-wide DNA methylation analysis of gene promoters in placenta tissue from three pregnancy trimesters. We identified large-scale differences in global DNA methylation levels between first, second and third trimesters, with an overall progressive increase in average methylation from first to third trimester. The most differentially methylated genes included many immune regulators, reflecting the change in placental immuno-modulation as pregnancy progresses. We also detected increased inter-individual variation in the third trimester relative to first and second, supporting an accumulation of environmentally induced (or stochastic) changes in DNA methylation pattern. These highly variable genes were enriched for those involved in amino acid and other metabolic pathways, potentially reflecting the adaptation of the human placenta to different environments. Conclusions : the identification of cellular pathways subject to drift in response to environmental influences provide a basis for future studies examining the role of specific environmental factors on DNA methylation pattern and placenta-associated adverse pregnancy outcomes. A total of 42 samples, with 18 first trimester, 10 second trimester, 14 full term placenta
Project description:Experimental approaches to define the relationship between gene expression and nuclear matrix attachment regions (MARs) have given contrasting and method-specific results. We have developed a next generation sequencing strategy to identify MARs across the human genome (MAR-Seq). The method is based on crosslinking chromatin to its nuclear matrix attachment sites to minimize changes during biochemical processing. We used this method to compare nuclear matrix organization in MCF-10A mammary epithelial-like cells and MDA-MB-231 breast cancer cells and evaluated the results in the context of global gene expression (array analysis) and positional enrichment of gene-regulatory histone modifications (ChIP-Seq). In the normal-like cells, nuclear matrix–attached DNA was enriched in expressed genes, while in the breast cancer cells, it was enriched in non-expressed genes. In both cell lines, the chromatin modifications that mark transcriptional activation or repression were appropriately associated with gene expression. Using this new MAR-Seq approach, we provide the first genome-wide characterization of nuclear matrix attachment in mammalian cells and reveal that the nuclear matrix–associated genome is highly cell-context dependent.
Project description:Experimental approaches to define the relationship between gene expression and nuclear matrix attachment regions (MARs) have given contrasting and method-specific results. We have developed a next generation sequencing strategy to identify MARs across the human genome (MAR-Seq). The method is based on crosslinking chromatin to its nuclear matrix attachment sites to minimize changes during biochemical processing. We used this method to compare nuclear matrix organization in MCF-10A mammary epithelial-like cells and MDA-MB-231 breast cancer cells and evaluated the results in the context of global gene expression (array analysis) and positional enrichment of gene-regulatory histone modifications (ChIP-Seq). In the normal-like cells, nuclear matrix–attached DNA was enriched in expressed genes, while in the breast cancer cells, it was enriched in non-expressed genes. In both cell lines, the chromatin modifications that mark transcriptional activation or repression were appropriately associated with gene expression. Using this new MAR-Seq approach, we provide the first genome-wide characterization of nuclear matrix attachment in mammalian cells and reveal that the nuclear matrix–associated genome is highly cell-context dependent.
Project description:Experimental approaches to define the relationship between gene expression and nuclear matrix attachment regions (MARs) have given contrasting and method-specific results. We have developed a next generation sequencing strategy to identify MARs across the human genome (MAR-Seq). The method is based on crosslinking chromatin to its nuclear matrix attachment sites to minimize changes during biochemical processing. We used this method to compare nuclear matrix organization in MCF-10A mammary epithelial-like cells and MDA-MB-231 breast cancer cells and evaluated the results in the context of global gene expression (array analysis) and positional enrichment of gene-regulatory histone modifications (ChIP-Seq). In the normal-like cells, nuclear matrix–attached DNA was enriched in expressed genes, while in the breast cancer cells, it was enriched in non-expressed genes. In both cell lines, the chromatin modifications that mark transcriptional activation or repression were appropriately associated with gene expression. Using this new MAR-Seq approach, we provide the first genome-wide characterization of nuclear matrix attachment in mammalian cells and reveal that the nuclear matrix–associated genome is highly cell-context dependent.
Project description:We hypothesized altered expression of proteases in cells capable of physiological invasion vs angiogenesis. We analyzed trophoblasts isolated from first trimester placenta that are invasive, and placental endothelial cells that gave a high angiogenic potential. We found different expression levels of most proteases. We found that the expression of proteases differs in cells performing invasion vs cells performing angiogenesis. Trophoblasts were isolated from first trimester placenta, endothelial cells were isolated from third trimester placenta. A pool of 5 preparations from different cell types was used for each microarray.
Project description:The placenta is a nonsupportive microenvironment for cancer cells. We showed that breast cancer cells (BCCL) were eliminated from placental implantation sites. During implantation, the placenta manipulates its surrounding matrix, which may induce BCCL elimination. Here, we explored the effect of placenta-induced ECM manipulations on BCCL. During experiments, BCCL (MCF-7/T47D) were cultured on placenta/BCCL-conditioned ECM (Matrigel used for first trimester placenta/BCCL culture and cleared by NH4OH). After culturing the cells, we analyzed cancer cell phenotype (death, count, aggregation, MMP) and signaling (microarray analysis and pathway validation). We found that the BCCL did not attach to previous placental implantation sites and instead, similarly to anoikis-resistant cells, migrated away, displayed increased MMP levels/activity, and formed aggregates in distant areas. T47D were less affected than the MCF-7 cells, since MCF-7 also showed modest increases in cell death, EMT, and increased proliferation. Microarray analysis of the MCF-7 highlighted changes in the integrin, estrogen, EGFR, and TGFb pathways. Indeed, placental ECM reduced ERa, induced Smad3/JNK phosphorylation and increased integrin-a5 expression (RGD-dependent integrin) in the BCCL. Addition of RGD or TGFbR/JNK inhibitors reversed the phenotypic changes. This study helps explain the absence of metastases to the placenta and why advanced cancer is found in pregnancy, and provides possible therapeutic targets for anoikis-resistant cells.
Project description:Heme Oxygenase-1 (HO-1) is expressed in many cancers and influences the growth, survivall and metastasis of tumors, however, the molecular mechanisms remains largely unknown. To identify a common mechanism of action of HO-1 in cancer, we studied the global effect of HO-1 on the transcriptome of multiple tumors. Genome-wide expression profiling of HO-1 expressing versus HO-1 silenced cancer cells and a further data mining analysis of the preexisting expression database of 190 human tumors of 14 cancer types led us to identify 14 genes, the expression of which correlated firmly and universally with that of HO-1 (P < 0.001). These genes included regulators of cell plasticity and extracellular matrix remodeling (MMP2, ADAM8, TGFβ1, BGN, COL21A1, PXDN), signaling (CRIP2, MICB), amino acid transport and glycosylation (SLC7A1 and ST3GAL2), estrogen and phospholipid biosynthesis (AGPAT2 and HSD17B1), protein stabilization (IFI30) and phosphorylation (ALPPL2). PXDN, one of the genes being co-expressed with HO-1, was selected for further analysis. Immunofluorescence and western blotting confirmed positive correlation of PXDN with HO-1 levels in BeWo cancer cells as well as co-localization in invasive extravillous trophoblast cells of first trimester placenta. Loss of HO-1 in BeWo cells correlated with reduced cell adhesion to Collagen type I, Fibronectin and Laminin. The adhesion-promoting effects of HO-1 were dependent on PXDN expression, as loss of PXDN in HO-1 expressing BeWo cells led to reduced cell attachment to Laminin and Fibronectin coated wells.