Apoptosis of HL60/VCR Cells Induced by Topotecan

Objective To gain insight into the mechanisms of topotecan(TPT) inducing apoptosis of acute myelogenous leukemia multidrug-resistant HL60/VCR cells. Methods Exposed HL60/VCR cells to different concentrations of TPT, morphologic evidence for apoptosis was determined by Wright-Gimsa and Acridine Orange/ethidium bromide(AO/EB) staining. Cell cycle, Sub-G1 and Annexin V FITC staining were detected by flow cytometry. The expression of active caspase-3, bcl-2 and Pgp were detected by Western blot. Results HL60/VCR cells treated by TPT are observed to have apoptosis characteristic morphological changes by Wright-Gimsa and AO/EB staining. The percentage of annexin V-positive cells was 26.8%. The apoptosis cells increased significantly with TUNNEL.The proportion of G 0/G 1 HL60/VCR cells treated by TPT was increased and the sub-G1 was 21.8%. Meanwhile, HL60/VCR cells treated by TPT expressed activated caspase-3, and the expression of bcl-2 decreased. However, the expression of Pgp didn't change. Conclusion TPT could induce apoptosis of HL60/VCR cells with appearance of active-caspase3 and lower expression of bcl-2.