The prognosis of colorectal cancer (CRC) stage II and III patients is still a challenge due to the difficulties of finding robust biomarkers and assays. The majority of published gene signatures of CRC have been generated on frozen colorectal tissues. Because collection of fresh frozen tissues is not routine and the quantity and quality of RNA derived from formalin-fixed paraffin-embedded (FFPE) tissues is vastly inferior to that derived from fresh frozen tissue, a clinical test for improving staging of colon cancer will need to be designed for FFPE tissues in order to be widely applicable. We have designed a custom Nanostring nCounter assay for quantitative assessment of expression of 414 gene elements consisting of multiple published gene signatures for colon cancer prognosis, and systematically compared the gene expression quantification between nCounter data from FFPE and Affymetrix microarray array data from matched frozen tissues using 414 genes.
Comparison of Nanostring nCounter® Data on FFPE Colon Cancer Samples and Affymetrix Microarray Data on Matched Frozen Tissues.
Disease
View SamplesHigh-throughput genomic studies have identified thousands of genetic alterations in colorectal cancer (CRC). Distinguishing driver from passenger mutations is critical for developing rational therapeutic strategies. Because only a few transcriptional subtypes exist in previously studied tumor types, we hypothesize that highly heterogeneous genomic alterations may converge to a limited number of distinct mechanisms that drive unique gene expression patterns in different transcriptional subtypes. In this study, we defined transcriptional subtypes for CRC and identified driver networks/pathways for each subtype, respectively. Applying consensus clustering to a patient cohort with 1173 samples identified three transcriptional subtypes, which were validated in an independent cohort with 485 samples. The three subtypes were characterized by different transcriptional programs related to normal adult colon, early colon embryonic development, and epithelial mesenchymal transition, respectively. They also showed statistically different clinical outcomes. For each subtype, we mapped somatic mutation and copy number variation data onto an integrated signaling network and identified subtype-specific driver networks using a random walk-based strategy. We found that genomic alterations in the Wnt signaling pathway were common among all three subtypes; however, unique combinations of pathway alterations including Wnt, VEGF, Notch and TGF-beta drove distinct molecular and clinical phenotypes in different CRC subtypes. Our results provide a coherent and integrated picture of human CRC that links genomic alterations to molecular and clinical consequences, and which provides insights for the development of personalized therapeutic strategies for different CRC subtypes.
Deciphering genomic alterations in colorectal cancer through transcriptional subtype-based network analysis.
No sample metadata fields
View SamplesPurpose: Aim of the study is to identify functional differences between the P1 and P2-HNF4a isoforms. To do this, we generated Tet-On inducible lines that express either the human (P1) HNF4a2 or (P2) HNF4a8 under control of DOX in the HCT116 human colon cancer cells. Methods: HNF4a2 and Parental lines were induced with 0.3 µg/mL DOX, while HNF4a8 line was induced with either 0.1 or 0.3 µg/mL DOX for 24 hours. Samples were generated by deep sequencing, using the Illumina TruSeq RNA. Result: There were common and unique dysregulated genes identified in the HNF4a2 and HNF4a8 lines (+DOX); more upregulated genes than downregulated genes in both the lines. Conclusion: The functional difference between HNF4a2 and HNF4a8 is that the latter tends to upregulate genes involved in proliferation and anti-apoptosis while HNF4a2 upregulates genes involved in growth suppression and cell death. Overall design: Tet-On inducible HCT116 cell (Parental, HNF4a2, and HNF4a8) lines, treated with (0.0, 0.1, or 0.3 µg/mL) DOX for 24 hours, were 50bp pair-ended sequenced in triplicate using Illumina TruSeq RNA Sample Prep v2 Kit.
Differential Effects of Hepatocyte Nuclear Factor 4α Isoforms on Tumor Growth and T-Cell Factor 4/AP-1 Interactions in Human Colorectal Cancer Cells.
No sample metadata fields
View SamplesColorectal carcinoma is the third leading cause of cancer-related death in the United States. In order to understand the mechanism/signaling pathways responsible for invasion, migration and metastasis in colorectal cancer, we developed an integrative and comparative genetic approach to infer transcriptional regulatory mechanisms underlying colon cancer progression. Accordingly, we filtered fourteen human colorectal cancer (CRC) microarray data sets, from an immune competent mouse model of metastasis to identify known and novel transcriptional regulators in CRC. Using this approach, Nuclear Factor of Activated T cells (NFAT) family of transcription factors were identified as metastasis driver of colon cancer. NFAT family of transcription factors is known to induce gene transcription in various disease processes, including carcinogenesis. We used parental and metastatic derivatives of MC38 mouse colon cancer cells (MC38Par and MC38Met, respectively) to evaluate the role of NFATc1 in cancer cell invasiveness. We found that high NFATc1 expression correlates with significantly increased (p<0.0001) Trans-Endothelial Invasion (TEI) in MC38Met cells. Conversely, RNAi-based inhibition of NFATc1 expression and functional inhibition with calcineurin inhibitor FK506 in MC38Met cells, both resulted in significant decreased TEI (p=0.0193 & p=0.0003). Furthermore, a set of predicted NFATc1 target mRNAs identified in our original analysis were downregulated by knock-down of NFATc1 or functional inhibition with FK506 in MC38Met cells. The expression level (mRNA) of predicted gene targets were high in human CRC specimens which had higher than median NFATc1 mRNA expression (n=11 out of total 22). The tumor-associated NFATc1 co-regulated gene signature is significantly correlated with both disease-specific and disease-free survival in Stage II and III CRC patients. We have successfully demonstrated a bioinformatics approach to identify a tumor promoter driver gene NFATc1. Our studies suggest a role of NFATc1 towards invasion and its co-regulated gene signature for poor outcomes in colorectal cancer.
Nuclear factor of activated T-cell activity is associated with metastatic capacity in colon cancer.
No sample metadata fields
View SamplesThe expression levels of many genes show wide natural variation among strains or populations. This study investigated the potential for animal strain-related genotypic differences to confound gene expression profiles in acute cellular rejection (ACR). Additional analysis allowed for selection of 49 candidate genes uniquely associated with ACR, but only after accounting for the unexpectedly large effect of animal strain. Studies of ACR that examine gene expression in peripheral blood may be confounded by strain differences. These results indicate the need for study designs that eliminate or control for the large effect of genetic background on the transcriptome of immune cells.
Impact of animal strain on gene expression in a rat model of acute cardiac rejection.
Specimen part
View SamplesWe used a reciprocal cross of Mus musculus and M. domesticus in which F1 males are sterile in one direction and fertile in the other direction, in order to associate expression differences with sterility.
Widespread over-expression of the X chromosome in sterile F₁hybrid mice.
Specimen part
View SamplesCarbonic anhydrase 1 (Car1), an early specific marker of the erythroid differentiation, has been used to distinguish fetal and adult erythroid cells since its production closely follows the - to -globin transition, but the molecular mechanism underlying transcriptional regulation of Car1 is unclear. Here, we show that Car1 mRNA decreases significantly when erythroid differentiation is induced in MEL cells. The Ldb1 protein complex including GATA1/SCL/LMO2 binds to the Car1 promoter in uninduced cells and reduced enrichment of the complex during differentiation correlates with loss of Car1 expression. Knockdown of Ldb1 results in a reduction of Ser2 phosphorylated RNA Pol II and Cdk9 at the Car1 promoter region, suggesting that Ldb1 is required for recruitment of Pol II as well as the transcription regulator P-TEFb to enhance elongation of Car1 transcripts. Taken together, these data show that Ldb1 forms a regulatory complex to maintain Car1 expression in erythroid cells.
Ldb1 regulates carbonic anhydrase 1 during erythroid differentiation.
Specimen part
View SamplesThe organs of multicellular species are comprised of cell types that must function together to perform specific tasks. One critical organ function is responding to internal or external change but little is known about how responses are tailored to specific cell types or coordinated among them on a global level. Here we use cellular profiling of five Arabidopsis root cell types in response to a limiting resource, nitrogen, to uncover a vast and predominantly cell-specific response that was largely undetectable using traditional methods. These methods reveal a new class of cell-specific nitrogen responses. As a proof-of-principle, we dissected one cell-specific response circuit that mediates nitrogen-induced changes in root branching from pericycle cells. Thus, cellular response profiling links gene modules to discrete functions in specific cell types.
Cell-specific nitrogen responses mediate developmental plasticity.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Elevated interferon gamma signaling contributes to impaired regeneration in the aged liver.
Sex, Treatment
View SamplesThe aim of this study was to investigate correlations between early subclinical findings (10 and 90 day histology and gene expression data) and late outcomes (transplant glomerulopathy and graft loss) in positive crossmatch kidney transplants (+XMKTx).
Early subclinical inflammation correlates with outcomes in positive crossmatch kidney allografts.
Specimen part
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