[Studies on programmed cell death induced by amsacrine and expression of bcl-2 in leukemia cell lines].
To study programmed cell death (PCD) in two human acute myelocytic leukemia cell lines in different differentiated phases, NB4(AML3) and HL-60(AML2). PCD cells were detected microscopically, DNA electrophoretically and flow cytometrically. Expression of bcl-2 gene was examined by immunohistochemistry staining. Exposed to 1-20 micrograms/ml m-AMSA for 6-12 h, morphological changes in NB4 cells were more evident than in HL-60 cells. Internucleosomal fragmentation(DNA ladders) was more marked in NB4 than in HL-60 cells. Flow cytometric analysis indicated that the number of PCD cells in NB4 cells was more than that in HL-60 cells. HL-60 cells had significantly higher mean bcl-2 level than NB4 cells. The high bcl-2 level in HL-60 cells may be related to their comparatively low sensitivity to m-AMSA-induced PCD.