JC-1, a sensitive probe for a simultaneous detection of P-glycoprotein activity and apoptosis in leukemic cells.

Background: JC-1 probe has been successfully used for the analysis of either apoptosis or P-glycoprotein (P-gp) activity. Therefore, we wanted to see if JC-1 could also simultaneously assess both, P-gp activity and apoptosis, in acute myeloid leukemia (AML) cells.

Methods: P-gp activity was measured using JC-1 and compared to the results of the Rhodamine 123 (Rh 123) assay in P-gp negative and P-gp positive cell lines, and 12 AML samples.

Semisynthetic homoharringtonine induces apoptosis via inhibition of protein synthesis and triggers rapid myeloid cell leukemia-1 down-regulation in myeloid leukemia cells.

Semisynthetic homoharringtonine (ssHHT) is now being evaluated in phase II clinical trials for the treatment of chronic myelogenous leukemia and acute myelogenous leukemia patients. Here, we examined the mechanism of the apoptosis induced by ssHHT in myeloid leukemia cells. First, we have shown that ssHHT induces apoptosis in HL60 and HL60/MRP cell lines in a time- and dose-dependent manner, and independently of the expression of Bax.