title: Silencing of miRNA-148a by hypermethylation activates the integrin-mediated signaling pathway in nasopharyngeal carcinoma.
abstract: MicroRNAs (miRNAs) play a pivotal role in carcinogenesis by suppressing oncogenes or tumor suppressor genes. Various studies have identified numerous miRNAs and their diverse targets; however, the consequences of dysregulated miRNAs in nasopharyngeal carcinoma (NPC) remain unclear. For this study, we found that miR-148a is downregulated through hypermethylation in NPC biopsies and NPC cell lines compared with adjacent normal and NP cells respectively. Promoter assays demonstrated that upstream stimulatory factor 1 (USF1) is a crucial transcription factor that activates miR-148a promoter activity. EMSA assays confirmed that purified USF1 binds better toward the unmethylated than the methylated CG-containing USF1 consensus probe. The ectopic expression of miR-148a inhibits cell migration in NPC cells through the suppression of integrin-mediated signaling by targeting VAV2, WASL and ROCK1. Biochemical and functional assays provided supporting evidence that these 3 genes are the downstream targets of miR-148a in NPC cells. Furthermore, immunohistochemical staining and Western blotting analysis revealed that the 3 oncogenic targets of miR-148a were overexpressed in NPC biopsies, suggesting that the inactivation of miR-148a caused by DNA methylation promotes NPC progression. Overall, our findings revealed that miR-148a can act as tumor suppressor miRNA and serve as a biomarker as well as a therapeutic target for NPC.
authors.affiliation: Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Department of Microbiology and Immunology, School of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Contributed equally to this work.
authors.forename: Hsin-Pai
authors.initials: HP
authors.lastname: Li
authors.affiliation: Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC).
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC).
authors.forename: Yi-Ru
authors.initials: YR
authors.lastname: Lai
authors.affiliation: Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC).
authors.forename: Jing-Xuan
authors.initials: JX
authors.lastname: Huang
authors.affiliation: Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital at Lin-Kou, Taoyuan, Taiwan, ROC.
authors.forename: Kai-Ping
authors.initials: KP
authors.lastname: Chang
authors.affiliation: Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Pathology Core, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Department of Pathology, Chang Gung Memorial Hospital at Lin-Kou, Taoyuan, Taiwan, ROC.
authors.forename: Chuen
authors.initials: C
authors.lastname: Hsueh
authors.affiliation: Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC). Department of Microbiology and Immunology, School of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China (ROC).
authors.forename: Yu-Sun
authors.initials: YS
authors.lastname: Chang
mesh_terms: D015153:Blotting, Western; D002277:Carcinoma; D002465:Cell Movement / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D024202:Electrophoretic Mobility Shift Assay; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D006801:Humans; D007150:Immunohistochemistry; D016023:Integrins / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics*; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics*; D014162:Transfection
chemical_list: D016023:Integrins; C550570:MIRN148 microRNA, human; D035683:MicroRNAs