Effects of overexpression of cyclin D1 and/or bcl-2 on IL-6-induced differentiation (A, B) and apoptosis (C) in each transfectant.

(A) Light micrograph of M1-V1, M1-D1, M1-bcl-2, and M1-W before and after 2-day culture with recombinant human (rh) interleukin 6 (IL-6). M1-V1, M1-D1, M1-bcl-2, and M1-W were cultured with 20 ng/mL of rhIL-6 for 2 days and cytocentrifugation preparation from each culture was stained with May-Gr ¸nwald-Giemsa (magnification × 100).(B) Flow cytometric analyses on expression of F4/80 before and after 2-day culture with rhIL-6. Expression of F4/80 was examined by staining with anti-F4/80 monoclonal antibody (—) with a reference to control antibody of the same isotype (---). (C) Cell cycle analysis on M1-V1, M1-D1, M1-bcl-2, and M1-W during the culture with rhIL-6. The cultured cells were subjected to propidium iodide staining, and DNA content was analyzed on FACSort. Cell cycle analysis was performed with Modfit LT2.0.