Induction of Apoptosis in Vitro by ARA-C, VP-16, MITOX, DNR, IDA and FLU in Myeloid Leukemic Cells

A number of anticancer drugs such as Cytosine Arabinoside (ARA-C), Etoposide (VP-16), Mitoxantrone (MITOX), Daunorubicin (DNR), Cisplatin and Amsacrine have been shown to induce programmed cell death (apoptosis) in leukemic cells. Apoptosis is morphologically characterized by early cell shrinkage, chromatin condensation, nuclear fragmentation, cell surface blebbing and membrane-bound apoptotic bodies. We investigated the in vitro induction of apoptosis by ARA-C, FLU (Fludarabine), VP-16, MITOX, DNR and IDA (Idarubicin) in the blast cells of 23 adult patients with untreated acute myeloid leukemia (2 M0, 2 Ml, 10 M2, 2 M4,4 M5,2 M6 and 1 M7). Mononuclear cells from the bone marrow and/or peripheral blood were isolated. Cell cultures were exposed to different concentrations of ARA-C, VP-16, FLU, IDA, DNR and MITOX at 37 °C for 24 h. Samples were analyzed using DNA gel electrophoresis and flow-cytometry after staining with propidium iodide. We also examined the morphology of 200 leukemic cells under light microscopy. The three methods gave comparable results. The most active drug in inducing internucleosomal fragmentation of DNA was FLU (82%); VP-16 and ARA-C induced apoptosis in a smaller number of cases (64 and 55%, respectively). MITOX, DNR and IDA- treated cells did not show fragmentation of DNA. Our results confirm the ability of some drugs to induce apoptosis in vitro in leukemic cells and demonstrate a good correlation between the detection of apoptosis by DNA electrophoresis, flow cytometry and light microscopy.