Effects of anti-CXCR4 monoclonal antibody 12G5 on proliferation and apoptosis of human acute myelocytic leukemia cell line HL-601

ObjectiveTo investigate the expression of CXCR4 on HL-60 cell line and the proliferation. apoptosis of HL-60 cell line cocultured with bone marrow stromal cells, so as to assess the possibility of 12G5, an anti-CXCR4 monoclonal antibody, in eradicating the minimal residual disease.MethodsThe activity of SDF-1 was inhibited by 10 μg/ml 12G5. After treatment with 12G5, the status of adhesion was observed, and the adhesion rates, apoptosis and cell cycles were detected after 24 h of treatment. Cell growth rates were measured by trypan blue exclusion. Cell growth curve was plotted, and the expression of PCNA and apoptosis related protein including PCNA, Bcl-2 and Fas were detected with immunohis-tochemical technique.Results(1) There was middling degree expression of CXCR4 on HL-60 membrane. From 0 h to 6 h, as the time of 12G5 incubation along, the expression of CXCR4 decreased gradually. (2) After treatment for 24 h, the adhesion rates in the experiment group and the control were (39.4 ± 7.9) and (51.4±5.9)%, respectively. (3) After treatment for 24 h, the percentage of HL-60 cells in G. G. phase were (55.21±4.9)%, and that in S phase and G2/M phase were (30.40±4.1)%, and (14.39 = 5.2)%, respectively, with the corresponding proportions being (44.67±2.2)%, (45.30±3.7)%, and (10.03±2.6)% in the control. (4) The percentage of apoptotic HL-60 cells was (8.95±1.7)% in the experiment group, compared to (3.97±2.4)% in the control. (5) The survival rates of HL-60 cells decreased markedly at 48 h to 96 h, and the proliferation slowed down at this time duration. (6) The expression of PCNA and Bcl-2 down-regulated significantly, but the Fas protein expression was up-regulated.Conclusion12G5 could inhibit the capability of adhesion and proliferation of HL-60 cells and it can induce more cells to enter G0/G1 phase and promote apoptosis. It may be helpful by inhibiting the bloactivity of SDF-1 with 12G5 in the therapy of marrow residual disease.