[Apoptosis resistance and its reversal in harringtonine resistant cell line].

Harringtonine (HT), a domestic antitumor drug extracted from Cephalotaxus hainanensis Li showed high chemotherapeutic efficacy on human acute granulocytic leukemia and acute myelocytic leukemia in clinics. Apoptosis of HL-60 cells can be induced by HT effectively; but for cells resistant to harringtonine, apoptosis can not be induced, even if the drug (HT) concentration is over 100 times of IC50 value. Although apoptosis occurred when its multidrugs resistance had been reversed by verapamil, compared with sensitive HL-60 cells, the time at which apoptosis happened delayed and the drug dosage increased. All these suggest that apoptotic resistance might be one of the marks of drug resistance in tumor cells, and apoptosis related factors could play a role in the formation of multidrug resistance.