Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Transcriptional profiling of lung cancer cells over-expression miR-34a.

ABSTRACT: The Zeb1 transcriptional repressor plays a key role in metastasis through the down-regulation of genes that are strong inducers of epithelial differentiation and inhibitors of stem-ness. Here we report that Zeb1 controls the expression of numerous oncogenic and tumor suppressive microRNAs (miRs). Zeb1 stimulated pro-migratory cytoskeletal processes by down-regulating miR-34a and activated Rho GTPases through Arhgap1, a Cdc42 GTPase activating protein and novel miR-34a target gene. Poor-prognosis human lung adenocarcinomas were highly enriched in a cytoskeletal gene signature activated by miR-34a down-regulation. These findings suggest that Zeb1 regulates a miR network and drives pro-migratory cytoskeletal processes through miR-34a. Total RNA was extracted from primary tumors from mice injected with 344SQ-vector and -miR-34a cells, and then hybridized to Affymetrix GeneChip Mouse Genome 430 2.0 array. Determination of differentially expressed genes was carried out.

ORGANISM(S): Mus musculus

SUBMITTER: Chad Creighton

PROVIDER: E-GEOD-38341 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

ZEB1 drives prometastatic actin cytoskeletal remodeling by downregulating miR-34a expression.

Ahn Young-Ho YH Gibbons Don L DL Chakravarti Deepavali D Creighton Chad J CJ Rizvi Zain H ZH Adams Henry P HP Pertsemlidis Alexander A Gregory Philip A PA Wright Josephine A JA Goodall Gregory J GJ Flores Elsa R ER Kurie Jonathan M JM

The Journal of clinical investigation 20120801 9

Metastatic cancer is extremely difficult to treat, and the presence of metastases greatly reduces a cancer patient's likelihood of long-term survival. The ZEB1 transcriptional repressor promotes metastasis through downregulation of microRNAs (miRs) that are strong inducers of epithelial differentiation and inhibitors of stem cell factors. Given that each miR can target multiple genes with diverse functions, we posited that the prometastatic network controlled by ZEB1 extends beyond these process ...[more]

PMID: 22850877

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Project description:Li-Fraumeni syndrome (LFS) is a disorder due to inherited mutations in the TP53 gene resulting in an increased risk of developing several types of cancer. MicroRNA miR-34a has been implicated downstream of p53 on the basis of being a direct transcriptional target and, when over-expressed, having pro-apoptotic phenotypes in cell lines. Moreover, miR-34a has been shown to be a modifier gene in the context of LFS, since its epigenetic silencing increases the likelihood of tumour development in patients with mutant TP53. However, the in vivo consequences of miR-34 loss are still unclear. For example, mice lacking all three (a,b,c) miR-34 homologs show no detectable abnormalities in p53 responses. The relative expression of different miR-34 genes in zebrafish was studied using qRT-PCR with specific assays. The miR-34a, miR-34b and miR-34c display unique onset of developmental expression and expression levels, with miR-34a being the most abundant and constant in expression. All of the miR-34 genes also showed clear induction by p53 when DNA-damaging treatments are performed. Using CRISPR-Cas9 technology, we generated a zebrafish miR-34a deletion mutant to further investigate the roles of miR-34a on its own and its association with the p53 pathway. Predictably, a miR-34a deletion mutant demonstrated absence of miR-34a, though without miR-34b and miR-34c compensation beyond baseline expression levels. Mutants survive to adulthood, show no overt phenotypes and have normal apoptotic responses to DNA-damaging irradiation or camptothecin treatments. To further explore the effects of miR-34a, we performed gene expression profiling using RNA-seq of wild-type and miR-34a deletion mutant zebrafish embryos at 8 hpf. This experiment was motivated by a previous report knock-down of miR-34a in zebrafish leads to dramatic increases in expression of miR-34a target genes. We therefore expected that this experiment will help define the set of miR-34a target genes. The results of this RNA-seq experiment showed that the loss of miR-34a led to large transcriptomic effects at 8 hpf (1573 genes UP and 1679 genes DOWN at 1.5-fold change and FDR < 0.05). There was no significant enrichment of predicted miR-34a target genes among the differentially regulated genes but some interesting biological trends were found and will be described in the paper associated with this dataset.

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Dataset Information

Transcriptional profiling of lung cancer cells over-expression miR-34a.

Publications

ZEB1 drives prometastatic actin cytoskeletal remodeling by downregulating miR-34a expression.

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