Project description:MicroRNA (miRNA) expression profiles for colon cancers were examined to investigate the miRNA involvement in colon carcinogenesis. miRNA microarray analysis identified statistical unique profiles, which could discriminate colon cancers from noncancerous colon tissues.
Project description:Sprouty proteins are evolutionarily conserved modulators of mitogen-activated protein kinase pathway. Sprouty2 appears to function as a tumor suppressor in cancers, whereas we reported earlier that Sprouty2 functions as an oncogene in colorectal cancer. To further understand the oncogenic potential of Sprouty2 in the colon, microRNA expression profile of colon cancer cells was investigated. Sprouty2 suppression in HCT116 colon cancer cells significantly increased MicroRNA 194-5p. Sprouty2 dependent regulation of microRNA194-5p and its biological targets were studied further for their tumor suppressive actions in reducing epithelial-mesenchymal transition in colorectal cancer. Sprouty2 knockdown was performed by infecting HCT116 cells with three different lentivirus expressing shRNAs against human Sprouty2 mRNA and a control non targeted non-silencing shRNA (Sprouty2 MISSION shRNA Lentiviral Transduction Particles; TRCN 0000007522, TRCN 0000231589, TRCN 0000231588 and a non-targeted shRNA control from Sigma) following lentiviral transduction protocols provided by Sigma. Due to the random integration of the lentivirus into the host genome, varying levels of Sprouty2 gene knockdown was expected in puromycin resistant colonies. Three colonies in triplicate that demonstrated highest to lowest level of Sprouty2 suppression, as assessed by western blotting, were selected. RNA samples from these colonies and one from non-targeted shRNA expressing colony were prepared for microRNA expression profile analysis. Pooled RNA samples from each group were shipped to Exiqon for microRNA profiling based on miRCURY LNATM array technology.
Project description:Sprouty proteins are evolutionarily conserved modulators of mitogen-activated protein kinase pathway. Sprouty2 appears to function as a tumor suppressor in cancers, whereas we reported earlier that Sprouty2 functions as an oncogene in colorectal cancer. To further understand the oncogenic potential of Sprouty2 in the colon, microRNA expression profile of colon cancer cells was investigated. Sprouty2 suppression in HCT116 colon cancer cells significantly increased MicroRNA 194-5p. Sprouty2 dependent regulation of microRNA194-5p and its biological targets were studied further for their tumor suppressive actions in reducing epithelial-mesenchymal transition in colorectal cancer.
Project description:A multi-step approach combining microarray profile and bioinformatics analysis was adopted to identify the CRC specific miRNA-mRNA regulatory network. First, differentially expressed miRNAs and mRNAs were found out in CRC samples compared with normal epithelial tissues by miRNA and mRNA microarray respectively. Secondly the target mRNAs of dysregualted miRNA were identified by a combination of Pearson correlation coefficient between the expression level of miRNAs and mRNAs and online miRNA target predicting databases. Thirdly, the biological pathways which the miRNA-mRNA pairs involved in were identified by DAVID. Finally, some of the dysregualted miRNAs and mRNAs were validated by qRT-PCR
Project description:MicroRNAs (miRNAs) have emerged as important gene regulators and are recognized as key players in tumorigenesis. miR-143 is reported to be down-regulated in several cancers, but knowledge of its targets in colon cancer remains limited. To investigate the role of miR-143 in colon cancer, we have employed a microarray based approach to identify miR-143 targets. Based on seed site enrichment analyses and unbiased word analyses, we found a significant enrichment of miRNA binding sites in the 3’-untranslated regions (UTRs) of transcripts down-regulated upon miRNA overexpression. Here we identify Hexokinase 2 (HK2) as a direct target of miR-143 and show that re-introduction of miR-143 in the colon cancer cell line DLD-1 results in a decreased lactate secretion, indicating that miR-143 down-regulation of HK2 affects glucose metabolism in colon cancer cells.
Project description:A multi-step approach combining microarray profile and bioinformatics analysis was adopted to identify the CRC specific miRNA-mRNA regulatory network. First, differentially expressed miRNAs and mRNAs were found out in CRC samples compared with normal epithelial tissues by miRNA and mRNA microarray respectively. Secondly the target mRNAs of dysregualted miRNA were identified by a combination of Pearson correlation coefficient between the expression level of miRNAs and mRNAs and online miRNA target predicting databases. Thirdly, the biological pathways which the miRNA-mRNA pairs involved in were identified by DAVID. Finally, some of the dysregualted miRNAs and mRNAs were validated by qRT-PCR RNA isolated from 8 colorectal cancer tissues and their corresponding adjacent normal tissues were analyzed.
Project description:MicroRNAs (miRNAs) have emerged as important gene regulators and are recognized as key players in tumorigenesis. miR-143 is reported to be down-regulated in several cancers, but knowledge of its targets in colon cancer remains limited. To investigate the role of miR-143 in colon cancer, we have employed a microarray based approach to identify miR-143 targets. Based on seed site enrichment analyses and unbiased word analyses, we found a significant enrichment of miRNA binding sites in the 3M-bM-^@M-^Y-untranslated regions (UTRs) of transcripts down-regulated upon miRNA overexpression. Here we identify Hexokinase 2 (HK2) as a direct target of miR-143 and show that re-introduction of miR-143 in the colon cancer cell line DLD-1 results in a decreased lactate secretion, indicating that miR-143 down-regulation of HK2 affects glucose metabolism in colon cancer cells. DLD-1 cells were transfected with 50 nM miR-143 duplex or mock transfected. Total RNA was harvested 24 hours post-transfection and analyzed on Affymetrix HG-U133 Plus 2.0 human arrays.
Project description:Hypoxia is the most prominent feature in human solid tumors and induces activation of hypoxia-inducible factors and their downstream genes to promote cancer progression. However, whether and how hypoxia regulates overall mRNA homeostasis is unclear. Here we show that hypoxia inhibits global-mRNA decay in cancer cells. Mechanistically, hypoxia induces the interaction of AGO2 with HOIL-1L/HOIP, two crucial components of a linear ubiquitin chain assembly complex, which co-localizes with miRNA-induced silencing complex and in turn catalyzes AGO2 occurring Met1-linked linear ubiquitination (M1-Ubi). A series of biochemical experiments reveal that M1-Ubi of AGO2 restrains miRNA-mediated gene silencing. Moreover, combination analyses of the AGO2-associated mRNA transcriptome by RIP-Seq and the mRNA transcriptome by RNA-Seq confirm that AGO2 M1-Ubi interferes miRNA-targeted mRNA recruiting to AGO2, and thereby facilitates accumulation of global mRNAs. By this mechanism, short-term hypoxia may protect overall mRNAs and enhances stress tolerance, whereas long-term hypoxia in tumor cells results in seriously changing the entire gene expression profile to drive cell malignant evolution.