BioProject

Autophagy plays an important role in physiology and tumorigenesis. We and others have demonstrated that Ha-ras overexpression induces autophagy in NIH3T3 cells. More...

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. Overall design: 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. Less...