title: MicroRNA-149 is epigenetically silenced tumor-suppressive microRNA, involved in cell proliferation and downregulation of AKT1 and cyclin D1 in human glioblastoma multiforme.
abstract: Aberrant DNA methylation has been shown to inactivate tumor suppressor genes during carcinogenesis. MicroRNA-149 (miR-149) was recently demonstrated to function as a tumor suppressor gene in glioblastoma multiforme (GBM). However, the potential linkage of miR-149 levels and the underlying epigenetic regulatory mechanism in human GBM has not been studied. We used quantitative real-time polymerase chain reaction to investigate the levels of miR-149 in GBM tissues, their matched adjacent normal tissues, and glioblastoma U87MG cell line. Using bisulfite genomic sequencing technology, DNA methylation status of upstream region of miR-149 was evaluated in study population groups and the U87MG cell line. After treatment of cells with 5-aza-2'-deoxycitidine (5-aza-dC), the DNA methylation status, gene expression, and target protein levels of miR-149 were investigated. Our studies revealed that methylation and expression levels of miR-149 were significantly increased and decreased, respectively in GBM patients relative to the adjacent normal tissues (P < 0.01). MiR-149 suppressed the expression of AKT1 and cyclin D1 and reduced the proliferative activities of the U87MG cell line. Treatment of U87MG cells with 5-aza-dC reversed the hypermethylation status of miR-149, enhanced the expression of its gene, and decreased target mRNA and proteins levels (P < 0.01). These findings suggest that the methylation mechanism is associated with decreased expression levels of miR-149, which may in turn lead to the increased levels of its oncogenic target proteins.
authors: a Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors: Asghar
authors: A
authors: Ghasemi
authors: b Department of Clinical Biochemistry, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.|c Research Center of Pediatric Infection Disease, Hazrat Rasol Akram Hospital of Iran University of Medical Sciences.
authors: Soudabeh
authors: S
authors: Fallah
authors: a Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors: Mohammad
authors: M
authors: Ansari
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001374:Azacitidine / Q000494:pharmacology; D001483:Base Sequence; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D001932:Brain Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects; D044127:Epigenesis, Genetic / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D005909:Glioblastoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; C530104:CCND1 protein, human; C551557:MIRN149 microRNA, human; D035683:MicroRNAs; D019938:Cyclin D1; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt; D001374:Azacitidine
keywords: glioblastoma; glioblastome; methylation; miR-149; méthylation