Flow Cytometric Analysis of the Cell Cycle of the Leukemic Cell Lines Treated with Etoposide and Cytosine Arabinoside.

ISHIYAMA, K., SATOH, S., IGARASHI, Y., KUMAGAI, H., YAHAGI, A. and SASAKI, H. Flow Cytometric Analysis of the Cell Cycle of the Leukemic Cell Lines Treated with Etoposide and Cytosine Arabinoside. Tohoku J. Exp. Med., 1994, 174 (2), 95-107-Effects of etoposide (VP-16) and cytosine arabinoside (Ara-C) on the cell cycle of HL-60 and THP-1 cells were studied by flow cytometry using the bromodeoxyuridine (BrdU)/DNA assay technique to investigate the efficacy of VP-16 for monocytic leukemia cells. VP-16 inhibited the proliferation of THP-1 cells more strongly than that of HL-60 cells at any concentrations used at 24 and 48hr. VP-16 arrested HL-60 and THP-1 cells in the G2/M phase and reduced them in the G0/G1 and early S phase at higher concentrations. There was no significant difference in the percentage of G2/M phase cells at the same concentration between both cells. However, reduction in the G0/G1 and early S phase cells was more marked in THP-1 than HL-60 cells significantly. On the other hand, Ara-C perturbed the cell cycle of HL-60 cells more than that of THP-1 cells at 24 and 48hr. These results suggest that the effects of VP-16 on the cell cycle may be more intense in THP-1 than HL-60 cells, and support the efficacy of VP-16 for treating monocytic leukemia in vivo.