Unknown,Transcriptomics,Genomics,Proteomics

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Identification Atg5-related microRNAs involved in the regulation of tumor formation

ABSTRACT: Autophagy plays an important role in physiology and tumorigenesis. We and others have demonstrated that Ha-ras overexpression induces autophagy in NIH3T3 cells. Autophagic machinery is regulated by a family of autophagy associated genes (Atg). The inducible Ha-ras oncogene was introduced into mouse embryo fibroblast Atg5 wild type [MEF-Atg5(+/+)] and Atg5 knock-out [MEF-Atg5(-/-)] cells and the stable cell lines MR and M5R were established, respectively. Our results showed that M5R cell induced larger tumor formation compared with MR cells while these two cell lines were subcutaneously injected into SCID mice under Ha-ras overexpression conditions. It indicates that Atg5 is involved in the suppression of Ras-related tumor formation. MicroRNA (miRNA), approximately 22 nucleotide of non-coding RNA, regulates transcription and translation of the target genes and is involved in cell differentiation and tumorigenesis. A miRNA microarray (932 probes) screening was conducted to identify the autophagy-tumorigenesis-related miRNAs. Among the significant genes, miR-224 was highly expressed in autophagy deficient cell and it induced tumors. Overexpression miR-224 enhanced the activity of migration and invasion in vitro and tumor formation in vivo. In conclusion, this is the first report to demonstrate that autophagy suppresses tumor formation through down-regulation of microRNA in this case miR-224. MR and M5R cell lines were treated with IPTG for 48 hr. In addition, these cell lines were subcutaneously injected into mice to induce tumor formation. The RNA samples were extracted from above cell lines and tumors. In this research, BEL/ITRI 15K V1.0 miRNA microarray chips were used to evaluate the miRNA expression profile.

ORGANISM(S): Mus musculus

SUBMITTER: Yen-Ju Lin

PROVIDER: E-GEOD-38911 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:We have compared the response to TGFbeta1 in normal and v-rasHa transduced primary mouse keratinocytes using NCI cDNA microarrays. This analysis reveals that Ha-ras alters global TGFbeta1 mediated gene expression in a gene specific manner. The expression pattern of TGFbeta1 immediate early response genes and down regulation of cell cycle control genes is not altered by Ha-ras but the induction of most extracellular matrix genes is blocked. Using Smad3 null keratinocytes, we find that the majority of TGFbeta1 responsive genes in primary keratinocytes are Smad3 dependent, but patterns of transcriptional responses suggest that the ability of Ha-ras to block TGFbeta1 mediated gene expression is not dependent on Smad3. However, the combination of oncogenic ras and loss of Smad3 prevents the TGFbeta1 dependent suppression of genes associated with cell cycle progression and apoptosis observed with either genotype alone. In addition several extracellular matrix genes are super-repressed by TGFbeta1 in the Ha-ras Smad3 null keratinocytes. These data provide a genomic framework for understanding how disruptions of TGFbeta signaling and oncogenic ras cooperate to promote premalignant progression of primary keratinocytes. Keywords: time series design RNA from Balb/c primary and ras keratinocytes treated for 1, 6, 24, and 48 hours with TGFbeta1 at 1ng/ml was compared to RNA from the corresponding untreated controls. For each timepoint sample from primary and ras cells, multiple arrays (including dye swaps) were analyzed. There are 6, 7, 6, and 5 arrays analyzed for RNA from primary keratinocytes treated for 1, 6, 24, and 48 hours as compared to RNA from untreated primary cells, respectively. There are 6, 8, 7, and 5 arrays analyzed for RNA from ras keratinocytes treated for 1, 6, 24, and 48 hours as compared to RNA from untreated ras cells, respectively. There are 50 arrays analyzed for the Balb/c time-course dataset. RNA from Smad3 WT and KO primary and ras keratinocytes treated 48 hours with TGFbeta1 were compared to RNA from its untreated corresponding controls. There are 6 arrays analyzed for the Smad3 WT/KO data set. There are 56 arrays in this series.

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Identification Atg5-related microRNAs involved in the regulation of tumor formation

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