title: MicroRNA-301a promotes cell proliferation via PTEN targeting in Ewing's sarcoma cells.
abstract: MicroRNAs (miRNAs) regulate cell proliferation and differentiation by affecting gene expression at the post-transcriptional level by binding to complementary sequences within mRNAs in cancer cells, indicating that miRNAs can function as tumor suppressors or oncogenes. Recent studies showed that dysregulation of miRNA expression was associated with increased tumorigenicity and poor prognosis in several types of cancers, including Ewing's sarcoma (ES). To explore possible oncogenic factors in ES, we conducted microarray-based investigation and profiled the changes in miRNA expression and their effects on downstream mRNAs in five ES cell lines and human mesenchymal stem cells (hMSCs). miR-301a was significantly upregulated, while the phosphatase and tensin homolog (PTEN) expression was significantly downregulated in all tested ES cells as compared to hMSCs. When anti-miR-301a was transfected into ES cell lines, PTEN expression was significantly enhanced, suggesting that PTEN might be a target of miR-301a in ES cells. The expression of protein kinase B (Akt), which is inversely correlated with PTEN expression, was significantly downregulated in anti-miR-301a-transfected cells. Additionally, the transfection of anti-miR-301a inhibited ES cell proliferation and cell cycle progression. Furthermore, downregulation of miR-301a in ES cells significantly suppressed tumor growth in vivo. Our results demonstrated the novel mechanism controlling PTEN expression via miR-301a in ES cells. Given that PTEN is a pivotal phosphatase factor that regulates cell cycle progression, apoptosis, and proliferation, these results might lead to development of new ES-related therapeutic targets.
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
authors: Masanori
authors: M
authors: Kawano
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
authors: Kazuhiro
authors: K
authors: Tanaka
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
authors: Ichiro
authors: I
authors: Itonaga
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
authors: Tatsuya
authors: T
authors: Iwasaki
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
authors: Hiroshi
authors: H
authors: Tsumura
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D009368:Neoplasm Transplantation; D051059:PTEN Phosphohydrolase / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D011379:Prognosis; D012512:Sarcoma, Ewing / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
chemical_list: C550735:MIRN301A microRNA, human; D035683:MicroRNAs; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human