title: Downregulation of miR-21 inhibits EGFR pathway and suppresses the growth of human glioblastoma cells independent of PTEN status.
abstract: MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs that regulate gene expression after transcription. Aberrant expression of miRNAs has been shown to be involved in tumorigenesis. We showed that miR-21 was one of the most frequently overexpressed miRNA in human glioblastoma (GBM) cell lines. To explore whether miR-21 can serve as a therapeutic target for glioblastoma, we downregulated miR-21 with a specific antisense oligonucleotide and found that apoptosis was induced and cell-cycle progression was inhibited in vitro in U251 (PTEN mutant) and LN229 (PTEN wild-type) GBM cells; xenograft tumors from antisense-treated U251 cells were suppressed in vivo. Antisense-miR-21-treated cells showed a decreased expression of EGFR, activated Akt, cyclin D, and Bcl-2. Although miR-21 is known to regulate PTEN and downregulation of miR-21 led to increased PTEN expression both endogenously and in a reporter gene assay, the GBM suppressor effect of antisense-miR-21 is most likely independent of PTEN regulation because U251 has mutant PTEN. Microarray analysis showed that the knockdown of miR-21 significantly altered expression of 169 genes involved in nine cell-cycle and signaling pathways. Taken together, our studies provide evidence that miR-21 may serve as a novel therapeutic target for malignant gliomas independent of PTEN status.
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Laboratory of Neuro-oncology, Tianjin Neurological Institute, Tianjin, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhou
authors.forename: Yu
authors.initials: Y
authors.lastname: Ren
authors.forename: Lynette
authors.initials: L
authors.lastname: Moore
authors.forename: Mei
authors.initials: M
authors.lastname: Mei
authors.forename: Yongping
authors.initials: Y
authors.lastname: You
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Baoli
authors.initials: B
authors.lastname: Wang
authors.forename: Guangxiu
authors.initials: G
authors.lastname: Wang
authors.forename: Zhifan
authors.initials: Z
authors.lastname: Jia
authors.forename: Peiyu
authors.initials: P
authors.lastname: Pu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Kang
mesh_terms: D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D056741:Cyclin D / Q000378:metabolism; D015536:Down-Regulation; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D005909:Glioblastoma / Q000378:metabolism*; D006801:Humans; D053858:Metabolic Networks and Pathways; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000378:metabolism*; D009368:Neoplasm Transplantation; D020411:Oligonucleotide Array Sequence Analysis; D016376:Oligonucleotides, Antisense; D051059:PTEN Phosphohydrolase / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction; D014183:Transplantation, Heterologous
chemical_list: D056741:Cyclin D; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D016376:Oligonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human