OBJECTIVETo investigate the effects of KCa3.1 channel inhibitor TRAM-34 on the proliferation and invasion of leukemia cell line HL-60.

METHODSHL-60 cells at logarithmic growth phase exposed to TRAM-34 at the final concentration of 25, 50, 75 and 100 nmol/L were used as experimental group. The HL-60 cells of control group was cultured in 10% fetal bovine serum-RPMI 1640. The proliferation inhibition rate of TRAM-34 on HL-60 cells was detected by adding MTT solution after 24, 48 and 72 h culture. The cell apoptotic rate and cell cycle distribution of HL-60 cells treated with TRAM-34 were evaluated by flow cytometry with Annexin V-FITC/propidium iodide(PI) double staining or PI single staining. The number of transmembrane cells was detected by Transwell at 24 and 48 h after treatment with TRAM-34. The effect of TRAM-34 on CDK6, P53 and MMP-2 mRNA level was detected by real-time quantitative PCR.

RESULTSCompared with the control group (0 nmol/L), the inhibition rate, apoptosis rate, G/Gphase cell proportion and P53 mRNA level all increased, but the percentages of cells in S phase, cell number penetrating the membrane and mRNA levels of CDK6 and MMP-2 in the TRAM-34-treated group decreased (P<0.05) except for 24 h proliferation rate of TRAM-34 at low concentration (25 nmol/L). The effect of TRAM-34 on the above indices was enhanced with the increase of concentration and prolongation of time, and the differences were statistically significant (P<0.05).

CONCLUSIONTRAM-34 can inhibit the proliferation and invasion of HL-60 cells, and can induce cell apoptosis and G/Garrest. The time and concentration of TRAM-34 have effect on the malignant behavior of HL-60 cells.