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Title: MiR-196b is epigenetically silenced during the pre-malignant stage of lung carcinogenesis      
keywords:
Transcriptome or Gene expression
ID:
PRJNA317575
description:
MicroRNA silencing by promoter hypermethylation may represent a mechanism by which lung cancer develops and progresses, but the microRNAs involved during malignant transformation are unknown. We previously established a model of pre-malignant lung cancer wherein we treated human bronchial epithelial cells (HBEC) with low doses of tobacco carcinogens. Here, we demonstrate that next-generation sequencing of carcinogen-transformed HBECs treated with the demethylating agent 5-aza-2'deoxycytidine revealed miR-196b and miR-34c-5p to be epigenetic targets. Bisulfite sequencing confirmed dense promoter hypermethylation indicative of silencing in multiple malignant cell lines and primary tumors. Chromatin immunoprecipitation studies further demonstrated an enrichment in repressive histone marks on the miR-196b promoter during HBEC transformation. Restoration of miR-196b expression by transfecting transformed HBECs with specific mimics led to cell cycle arrest mediated in part through transcriptional regulation of the FOS oncogene, and miR-196b re-expression also significantly reduced the growth of tumor xenografts. Luciferase assays demonstrated that forced expression of miR-196b inhibited the FOS promoter and AP-1 reporter activity. Finally, a case-control study revealed that methylation of miR-196b in sputum was strongly associated with lung cancer (OR = 4.7, p<0.001). Collectively, these studies highlight miR-196b as a tumor suppressor whose silencing early in lung carcinogenesis may provide a selective growth advantage to pre-malignant cells. Targeted delivery of miR-196b could therefore serve as a preventive or therapeutic strategy for the management of lung cancer. Overall design: Nine tumor-derived cell lines (H1568, H1975, H2023, H2170, H23, CALU6, SW900, H1993, and H2085), HBEC1MBT, and HBEC2MBT were treated with vehicle or 5-aza-2’deoxycytidine and subjected to miRNA NGS.
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landingpage: http://www.ncbi.nlm.nih.gov/bioproject/PRJNA317575
authentication:
none
authorization:
none
ID:
pmid:27302168
name:
Homo sapiens
ncbiID:
ncbitax:9606
abbreviation:
NCBI
homePage: http://www.ncbi.nlm.nih.gov
ID:
SCR:006472
name:
National Center for Biotechnology Information
homePage: http://www.ncbi.nlm.nih.gov/bioproject
ID:
SCR:004801
name:
NCBI BioProject