MiR-18b inhibits cell proliferation in Jeko-1 and Z-138 cells lines. (A) Relative expression levels of miR-18b in Z-138 and Jeko-1 compared with MCL patient samples expressing high (PTS High) or low (PTS Low) miR-18b. Results are expressed as means ± standard deviation (SD). (B) Cells were transfected with 1 μM scrambled (Scr.) miRNA control or miR-18b mimic for 6 days, after which cell numbers were determined by XTT assay. Results are expressed as means ± SD. Statistical analyses were performed using the Student t test. *P ≤ .05. (C) Apoptosis was studied by flow cytometry in Annexin V-PE/7 AAD–stained cells 24 hours after transfection with Scr. miRNA control or miR-18b mimic. (D) Growth curves for cells transfected with Z-138 and Jeko-1. Cell number was determined 0 to 8 days after transfection using the XTT assay. Results are expressed as means ± SD. OD, optical density.