In vitro study of the apoptosis effect of DNR on HL-60 cells and its relationship with ROS, CER and NF-kappaB]

OBJECTIVE: To study the effect of DNR on HL-60 cells apoptosis in vitro and the related mechanism. METHODS: The apoptosis of HL-60 was observed by microscope, flow cytometry (FCM) and DNA electrophoresis and various apoptosis-associated proteins expression by immunocytochemistry (IC) and FCM assays; the changes of apoptosis in HL-60 cells treated with DNR or suppressors PDTC or FB1 were also observed. RESULTS: When treated with 0.2 approximately 2.0 micro mol/L DNR, the percentage of apoptotic HL-60 cells increased with the dose increasing and the time extending, and the typical apoptotic cells and the appearance of apoptotic DNA ladder were observed. It was shown that after treatment with 1 micro mol/L DNR, the fluorescence intensity index (FI) of both bcl-2 and c-myc in HL-60 cells decreased, the FI of Bax, caspase-3 increased at 2 h, but decreased at 5 h, the FI of NF-kappaB increased. After adding PDTC, the apoptosis percentage of HL-60 cells decreased, but FB1 didn't present these effect. CONCLUSION: It suggested from the results that at certain concentration, DNR can induce the apoptosis of HL-60 cells in vitro. The mechanism was supposed by suppressing the expression of bcl-2 and c-myc and activating the expression of Bax and caspase-3, NF-kappaB and ROS had the marked correlation with the apoptosis process, but the ceramide synthase wasn't associated with it.