Influence of interferon alpha-2b on inhibiting proliferation and promoting apoptosis of human promyelocytic leukemia HL-60 cell line / 中国组织工程研究

ABSTRACT

BACKGROUND: The existence of minimal residual leukemia cells is the main cause for the recurrence of acute leukemia in children, and immunological biological therapy has attracted more and more attentions in the various methods from eliminating minimal residual disease. Previous studies have found that interferon α-2b can effectively inhibit the increase of tumor cells in vivo in children with neuroblastoma and malignant lymphoma, whether it can inhibit the increase of leukemia cells?OBJECTIVE: To investigate the effects of interferon α-2b in vitro on leukemia cells.DESIGN: A comparative observation taking human promyelocytic leukemia HL-60 cell line as the material.SETTING: Cell Culture Room; Immunological Laboratory; Cell Room, Institute of Pediatrics, Affiliated Hospital,Medical College of Qingdao University.MATERIALS: HL-60 cell line was provided by Shandong Institute of Basic Medical Sciences. Interferon α-2b was purchased from Megagene Company Fluorescein isothiocyanate (FTTC) rabbit-anti-rat Ig solution (CatEK001) and CD13 anti-human monoclonal antibody solution (Cat. DK013Y) were purchased from Union Stem Cell & Gene Engineering Co.,Ltd.METHODS: The experiments were carried out in the Institute of Pediatrics, Affiliated Hospital, Medical College of Qingdao University from March to September 2005. HL-60 cells culture system was established in vitro, and the oncentration was adjusted to 1×109 L-1. The cells were divided into control group and experimental group. In the experimental group, each well was added by interferon-α-2b with the terminal concentration of 5×105, 1×106, 2×106,5×106 and 1×107 U/L, respectively. In the control group, each well was added by saline of the same volume. The cells were cultured continuously for 48 hours. The morphological changes of HL-60 cells were observed using Wright's staining under light microscope; Cell apoptosis was observed using acridine orange/ethidium bromide double staining; Antigen expression and maturation and differentiation on cell membrane were observed by determining CD13 protein expression; Proliferation and activity of HL-60 were detected with methyl-thiazol-tetrazolium (MTT) assay.MAIN OUTCOME MEASURES: The occurrence of apoptosis was judged according to the uniformity and staining of HL-60 nuclear chromatin; HL-60 cell proliferation was judged according to the absorbance (A) value; The maturation of HL-60 cells was judged according to the number of positive CD13 cells.RESULTS: ① HL-60 cell apoptosis: The cells were cultured for 48 hours. When the concentration of interferon α-2b was 5×105 U/L, there were mainly early apoptotic HL-60 cells; When the concentration was 1×107 U/L, there were mainly late apoptotic cells, and the apoptotic rate was significantly higher than those in the control group (P ＜ 0.01 ).② HL-60 cell proliferation: The A values in the experimental groups treated with interferon α-2b of 2×106 U/L and 1 ×107 U/L were significantly lower than that in the control group (P ＜ 0.01). ③ Maturation of HL-60 cells: The percentages of positive CD13 cells in the experimental groups treated with interferon α-2b of 1 ×106 and 1 ×107 U/L were significantly lower than that in the control group (P ＜ 0.01).CONCLUSION: It is concluded that interferon α-2b can enhance the apoptosis, inhibit the proliferation and promote maturation and differentiation of HL-60 cells.