ZM-66, a New Podophyllotoxin Derivative Inhibits Proliferation and Induces Apoptosis in K562/ADM Cells

To investigate the anti-tumor effect of ZM-66 on multidrug-resistant leukemic cell line K562/ADM. The K562/ADM cells were treated with varying concentrations (0, 1, 2, 4×10−3 mmol/L) of ZM-66 or etoposide for 24 hours. The proliferation was detected by Sulforhodamine B Sodium Salt (SRB) assay and apoptosis was detected by flow cytometry analysis and fluorescent staining. In addition, the expression levels of p53 and bax genes in K562/ADM cells were detected by RT-PCR analysis. The level of P-glycoprotein (P-gp), P53 and Bax protein in K562/ADM cells were detected by Western blot assay. SRB assay demonstrated that etoposide had little inhibitory effect on K562/ADM cells, whereas ZM-66 (1, 2, 4×10−3 mmol/L) had significantly inhibitory effect on K562/ADM cells (all P