Overexpression of miR-155 enhances B-cell lymphoma growth by targeting TBRG1
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ABSTRACT: MYC regulates the expression of multiple microRNA (miRNA) genes and defines the Burkitt lymphoma (BL) miRNA signature. Here, we investigate the role of the MYC-regulated miRNAs by gain- and loss-of-function analysis. Overexpression of 5 miRNAs that were significantly downregulated by MYC resulted in strong (miR-150, miR-26a, miR-26b) and mild (miR-29a, let-7a) impaired cell growth. Overexpression of miR-155 increased proliferation of BL cells. By RNA immunoprecipitation of Argonaute 2 in BL cells with and without miR-155 we identified 54 miR-155 target genes. Using an shRNA approach we identified TBRG1 (NIAM1) as a miR-155 target gene that copied the miR-155-induced phenotype upon its inhibition. Analysis of TBRG1 protein expression and miR-155 levels in primary cases of B-cell lymphoma revealed that miR-155 levels are significantly lower in TBRG1 positive cases suggesting that TBRG1 is also regulated by miR-155 in primary B-cell lymphoma. Our data demonstrate that overexpression of individual MYC-repressed miRNAs has a strong suppressive effect on BL cell growth, whereas overexpression of miR-155 enhances B-cell lymphoma growth by targeting the tumor suppressor gene TBRG1. Gene expression profile was performed in ST486 Burkitt lymphoma cell line in 4 samples: ST486 EV (empty MXW-PGK-IRES-GFP vector) total cell lysate, ST486 EV Ago2-IP, ST486 miR-155 (ST486 with ectopic miR-155) total cell lysate, ST486 miR-155 Ago2-IP.
ORGANISM(S): Homo sapiens
SUBMITTER: Anke van den Berg
PROVIDER: E-GEOD-64484 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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