miR-28 expression in the Burkitt lymphoma cell line P3HR1

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.