Project description:In response to polarization cues, cultured Caco-2 cells, a human colon adenocarcinoma-derived cell line, form a polarized epithelium resembling normal enterocytes. We investigated potential signaling mechanisms activated by Caco-2 cells that might trigger the genome-wide transcriptional reprogramming that accompanies polarization (Saaf et al, submitted-I). cDNA microarrays were used to compare the transcriptional profile of Caco-2 polarization to the gene expression profiles of normal human colon and colon tumors. The transcript profile of proliferating, non-polarized Caco-2 cells has striking parallels to the gene expression profile of human colon cancer in vivo. However, as Caco-2 cells develop polarity, the gene expression profile shifts to one more closely resembling that of normal colon tissue, suggesting that the underlying regulatory mechanisms that mediate Caco-2 cell polarization are similar to those that occur during in vivo enterocyte differentiation. We show that transcriptional re-programming of Caco-2 cells during development of cell polarity occurs in the context of signaling pathways that are regulated in a manner that is remarkably similar to those in normal intestinal development. For example, transcriptional targets of the Wnt pathway are tightly regulated during Caco-2 cell polarization, mimicking the gradient of Wnt-mediated transcription in the crypt (high expression) to villus (low expression) axis in human intestine. However, Caco-2 cells lack full-length APC necessary for normal Wnt-regulated degradation of beta-catenin. Biochemical analysis indicates that regulation of the Wnt pathway occurs in the nucleus at the level of activation of target genes by the beta-catenin-TCF complex, revealing a novel additional mechanism by which intestinal cells may regulate Wnt signaling during their maturation. In addition, other signaling pathways including Notch, BMP, Hedgehog, and growth factor, were temporally regulated during Caco-2 cell polarization. Surprisingly, modulation of these signaling pathways in Caco-2 cells occurs in the absence of morphogen gradients and interactions with stromal cells characteristic of enterocyte differentiation in situ. This dataset contains gene expression profiles of 9 normal colon samples and 15 colon tumor samples. Samples of tumor and normal colon mucosa were collected from colon cancer resection from Department of Surgery, Queen Mary Hospital University of Hong Kong. Tissue was frozen in liquid nitrogen within 30 min of resection. Nonneoplastic mucosa from colon was dissected free of muscle and histologically confirmed to be tumor free by frozen section. Total RNA was extracted using Trizol (Invitrogen, Carlsbad, CA) from each tissue sample and processed for microarray hybridization. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Disease State: Tumor/Normal colon samples Using regression correlation

Project description:In response to polarization cues, cultured Caco-2 cells, a human colon adenocarcinoma-derived cell line, form a polarized epithelium resembling normal enterocytes. We investigated potential signaling mechanisms activated by Caco-2 cells that might trigger the genome-wide transcriptional reprogramming that accompanies polarization (Saaf et al, submitted-I). cDNA microarrays were used to compare the transcriptional profile of Caco-2 polarization to the gene expression profiles of normal human colon and colon tumors. The transcript profile of proliferating, non-polarized Caco-2 cells has striking parallels to the gene expression profile of human colon cancer in vivo. However, as Caco-2 cells develop polarity, the gene expression profile shifts to one more closely resembling that of normal colon tissue, suggesting that the underlying regulatory mechanisms that mediate Caco-2 cell polarization are similar to those that occur during in vivo enterocyte differentiation. We show that transcriptional re-programming of Caco-2 cells during development of cell polarity occurs in the context of signaling pathways that are regulated in a manner that is remarkably similar to those in normal intestinal development. For example, transcriptional targets of the Wnt pathway are tightly regulated during Caco-2 cell polarization, mimicking the gradient of Wnt-mediated transcription in the crypt (high expression) to villus (low expression) axis in human intestine. However, Caco-2 cells lack full-length APC necessary for normal Wnt-regulated degradation of beta-catenin. Biochemical analysis indicates that regulation of the Wnt pathway occurs in the nucleus at the level of activation of target genes by the beta-catenin-TCF complex, revealing a novel additional mechanism by which intestinal cells may regulate Wnt signaling during their maturation. In addition, other signaling pathways including Notch, BMP, Hedgehog, and growth factor, were temporally regulated during Caco-2 cell polarization. Surprisingly, modulation of these signaling pathways in Caco-2 cells occurs in the absence of morphogen gradients and interactions with stromal cells characteristic of enterocyte differentiation in situ. This dataset contains gene expression profiles of 9 normal colon samples and 15 colon tumor samples. Samples of tumor and normal colon mucosa were collected from colon cancer resection from Department of Surgery, Queen Mary Hospital University of Hong Kong. Tissue was frozen in liquid nitrogen within 30 min of resection. Nonneoplastic mucosa from colon was dissected free of muscle and histologically confirmed to be tumor free by frozen section. Total RNA was extracted using Trizol (Invitrogen, Carlsbad, CA) from each tissue sample and processed for microarray hybridization. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Disease State: Tumor/Normal colon samples Keywords: disease_state_design

Project description:Lung cancer is one of the most common and fatal cancer worldwide. There are two major types of lung cancer, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Recently, gefitinib, a small molecule, which target tyrosine kinase, has been regarded as the first-line treatment in NSCLC patients. However, several patients have been observed tumor recurrence and eventually developed progressive outcomes after target therapy. Thus, an effective therapeutic approach need to be explored. Here, we found that ectopically expressed ATP synthase on plasma membrane exhibited gefitinib-resistance properties in lung cancer cell lines. Furthermore, we unraveled that citreoviridin, an ectopic ATP synthase inhibitor, suppressed the abilities of both proliferation and colony formation in lung cancer cell lines. To elucidate the comprehensive mechanism regulated by citreoviridin, we performed microarray analysis. The results indicated that not only mRNAs but also long non-coding RNAs (lncRNAs) are involved in citreoviridin-treated cell death. One of the well-known lncRNAs, growth arrest-specific transcript (GAS5), was robustly upregulated after citreoviridin treatment. In order to investigate the upstream modulator of GAS5, we utilized chromatin immunoprecipitation (ChIP) assay and revealed that E2F transcription factor 1 (E2F1) could bind to the promoter of GAS5. Consistently, both microarray and qPCR data showed the expression level of E2F1 was negatively correlated to GAS5 after citreoviridin treatment. The evidence suggests that E2F1 might be a potential repressor of GAS5. Furthermore, combining microarray and Gene Set Enrichment Analysis (GSEA) analysis as well as qPCR demonstrated that p53 pathway was activated. To further realize the GAS5-p53 regulating network, RNA-protein pull-down assay followed by LC-MS/MS will be utilized to dissect the GAS5-interacting proteomic profiling.From the results, we identified 107 GAS5-interacting proteins in common from A549 and H1975 cell lines. Our proteomics experiments identified topoisomerase 2-alpha (TOP2A) as the key protein involved in the citreoviridin-regulated gefitinib-resistance pathway, therefore, we picked out TOP2A for further study. Additionally, we further validated the interaction between TOP2A and GAS5 by western blot and RNA immunoprecipitation (RIP). Taken together, this study suggests targeting E2F1/GAS5/p53 axis is a potential therapeutic strategy for gefitinib-resistant lung cancer.

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Homo sapiens

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