miR-181a expression is significantly decreased in ABC populations. miR-181a expression in (A) DLBCL cell lines that are classified as GCB-like or ABC-like (2 independent experiments in triplicates per cell line). (B) De novo primary DLBCL tumors (GCB-like, n = 9; ABC-like, n = 8). (C) ABC-like (n = 19) and GCB-like (n = 20) DLBCL tumors (P = .0015) from miRNA microarray data set, GSE 15250.16 (D) Different stages of mature B-cell differentiation subsets enriched from human tonsils by multiple purification steps that are described in supplemental Materials and methods (naïve, n = 7; centroblasts, n = 6; plasmablasts, n = 6; memory, n = 6; and plasma cells, n = 3). Lymphocytes were gated on CD19. Centroblasts (CD77+IgD−CD38+) and plasmablasts (IgD−CD38++CD27+CD20+) were distinguished based on the noted surface molecules expression. (E) Quantitative real-time–PCR miRNA assay analyses in human B cells purified from the blood of healthy donors and in vitro activated with anti-human IgM F (ab’)2 (10 μg/mL) for 30 minutes (n = 3; 2 independent experiments). Total RNAs extracted from the noted B-cell populations were analyzed for the expression of miR-181a. The expression was corrected for RNU6B levels. Shown is the change in mean normalized miR-181a expression ± standard error of the mean (SEM) upon stimulation. Statistical significance was determined by Student t test. *P < .05; **P < .01; ***P < .001; ****P < .0001. ns, not significant.
