Mechanism of Bcl-2 BH4 selective inhibitor BDA-366 on NK/T cell lymphoma cells / 国际肿瘤学杂志

ABSTRACT

Objective:To investigate the inhibitory effect and killing mechanism of Bcl-2 BH4 selective inhibitor BDA-366 on NK/T cell lymphoma (NK/TCL) .Methods:Human NK cell leukemia cell line YT and human NK/TCL cell line NK92 cells were treated with 0, 0.05, 0.10, 0.20, 0.30, 0.40, 0.50 μmol/L BDA-366. CCK-8 assay was used to calculate the half inhibitory concentration (IC 50) value of BDA-366 on these cells. The apoptosis levels of cells in control group and IC 50 BDA-366 treated group were detected by flow cytometry. Western blotting was used to detect the expression levels of apoptosis-related proteins in cells of control group and 1/2 IC 50, IC 50, 2× IC 50 BDA-366 treated groups. TMRE and Fluo-3 fluorescent probe were used to detect mitochondrial membrane potential of control group and IC 50 BDA-366 treated group, and the intracellular Ca 2+ concentration of control group, IC 50, 2× IC 50 BDA-366 treated groups. NOD-SCID mice in control group and 10 mg/kg BDA-366 intraperitoneal injection group were weighed and HE staining was performed to evaluate the toxicity of BDA-366 in vivo. Results:The IC 50 of BDA-366 for YT and NK92 cells were 0.065 and 0.086 μmol/L respectively. The apoptosis rates of YT cells in the control group and 0.065 μmol/L BDA-366 group were (6.62±1.59) % and (34.60±3.06) % respectively. The apoptosis rates of NK92 cells in the control group and 0.086 μmol/L BDA-366 group were (5.57±0.88) % and (29.18±0.90) % respectively, both with statistically significant differences ( t=14.05, P<0.001; t=32.58, P<0.001). The relative expression of Bax in NK92 cells of the control group, 0.043, 0.086 and 0.172 μmol/L BDA-366 groups were 0.85±0.00, 1.26±0.04, 1.51±0.18, 1.15±0.10 ( F=20.70, P<0.001), the relative expression of Bax in BDA-366 groups were higher than that in the control group (all P<0.05). The fluorescence intensity of TMRE of YT cells in the control group and 0.065 μmol/L BDA-366 group were 8 372.00±330.47 and 6 419.67±311.34, and that of NK92 cells in the control group and 0.086 μmol/L BDA-366 group were 9 169.00±535.72 and 7 311.67±295.52 respectively, and there were statistically significant differences ( t=7.45, P=0.002; t=5.26, P=0.006). In YT cells, the intracellular Ca 2+ concentrations of 0.065 and 0.130 μmol/L BDA-366 groups were significantly higher than that of the control group (5 791.67±220.45, 6 729.33±585.39, 4 874.67±112.61, F=19.16, P=0.003) ( P=0.039; P=0.002). In NK92 cells, the intracellular Ca 2+ concentrations of 0.086 and 0.172 μmol/L BDA-366 groups were significantly higher than that of the control group (4 553.67±17.62, 4 740.33±254.50, 4 185.67±17.67, F=10.96, P=0.010) ( P=0.039; P=0.007). There was no statistically significant difference in body weight change on day 12 compared with day 0 of NOD-SCID mice between BDA-366 group and control group [ (3.18±0.01) g vs. (2.73±0.58) g, t=0.60, P=0.570], and HE staining showed no abnormal morphology of heart, liver, spleen, lung and kidney in BDA-366 group. Conclusion:BDA-366 promotes NK/TCL cells apoptosis in vitro, but does not cause weight loss and morphological changes of organs by HE staining in vivo. The inhibitory effect of BDA-366 on NK/TCL cells may be achieved by increasing Bax expression, inducing Ca 2+ release and reducing mitochondrial membrane potential.