Project description:Burkitt lymphoma (BL) is a highly aggressive B cell non-Hodgkin lymphoma (B-NHL), which originates from germinal center (GC) B cells and harbors translocations deregulating the MYC oncogene. A comparative analysis of microRNAs (miRNAs) expressed in normal and malignant GC B cells identified miR-28 as significantly down-regulated in BL, as well as in other GC-derived B-NHL. We show that re-expression of miR-28 impairs cell growth and clonogenic properties of BL cells by modulating several targets including MAD2L1, a component of the spindle checkpoint whose down-regulation is essential in mediating miR-28-induced growth-arrest, and BAG1, an activator of the ERK pathway. P3HR1 Burkitt lymphoma cell line was engineered to display inducible expression of GFP alone or GFP in combination with the miR-28 precursor from the pRTS1 vector upon doxycycline treatment. Two bulk populations (A and B) were established for both the control (GFP alone) and the miR28-expressing (GFP and miR-28 precursor) cells. Cells were induced with 0.1ug/ml doxycycline for 12h or 24h. Induction was performed on each bulk population in triplicates.
Project description:Burkitt lymphoma (BL) is a highly aggressive B cell non-Hodgkin lymphoma (B-NHL), which originates from germinal center (GC) B cells and harbors translocations deregulating the MYC oncogene. A comparative analysis of microRNAs (miRNAs) expressed in normal and malignant GC B cells identified miR-28 as significantly down-regulated in BL, as well as in other GC-derived B-NHL. We show that re-expression of miR-28 impairs cell growth and clonogenic properties of BL cells by modulating several targets including MAD2L1, a component of the spindle checkpoint whose down-regulation is essential in mediating miR-28-induced growth-arrest, and BAG1, an activator of the ERK pathway.
Project description: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.
Project description:RNA-Seq profiling of Burkitt Lymphoma cell line (BL2) with B-cell activating factor (BAFF) for 24 hrs . The Burkitt Lymphoma cell line were either only cultured in cell culture medium supplemented with 10 mM HEPES at 1 × 106 cells/ml or additionally incubated with B-cell activating factor (BAFF) for 24 hrs