He Pengcheng, Liu Yanfeng, Zhang Mei, Wang Xiaoning, Xi Jieying, Wu DI, Li Jing, Cao Yunxin
Department of Hematology, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061;
Exp Ther Med. 2012 May;3(5):776-780. doi: 10.3892/etm.2012.488. Epub 2012 Feb 16.
In order to investigate the effect and mechanisms of interferon (IFN)-γ in combination with all-trans-retinoic acid (ATRA) on NB4 cells [ATRA-sensitive acute promyelocytic leukemia (APL) cell line] and NB4-R1 cells (ATRA-resistant APL cell line) and to search for a novel approach to solve the problem of ATRA resistance in APL, we initially treated NB4 and NB4-R1 cells with IFN-γ, ATRA and IFN-γ in combination with ATRA, respectively. The cell proliferation was then tested by MTT assay, and the cell differentiation was tested through light microscopy, by NBT test and flow cytometry (FCM). The expression of promyelocytic leukemia (PML) protein was observed by indirect immune fluorescent test. Results showed that ATRA inhibited the growth of NB4 cells, however, it could not inhibit the growth of NB4-R1 cells. IFN-γ inhibited the growth of both NB4 and NB4-R1 cells. Meanwhile, the growth inhibition effect of IFN-γ in combination with ATRA on both NB4 and NB4-R1 cells was significantly stronger than that of any single drug treatment. The results of the NBT reduction test and CD11b antigen detection by FCM indicated that IFN-γ induces the differentiation of NB4 and NB4-R1 cells to some extent. Moreover, the maturation degree of both NB4 and NB4-R1 cells induced by IFN-γ in combination with ATRA was more significant than that of IFN-γ or ATRA alone. After treatment with IFN-γ, the number of fluorescent particles in NB4 and NB4-R1 cell nuclei was higher than those in the control group, which indicated that IFN-γ may induce the expression of PML protein. Together, IFN-γ augments the proliferation inhibition effect of ATRA on NB4 and NB4-R1 cells through enhancing the expression of PML protein. IFN-γ in combination with ATRA not only strengthens the induction differentiation effect of ATRA on NB4 cells, but also can partially induce the maturation of NB4-R1 cells with ATRA resistance.
为了研究干扰素（IFN）-γ联合全反式维甲酸（ATRA）对NB4细胞[对ATRA敏感的急性早幼粒细胞白血病（APL）细胞系]和NB4-R1细胞（对ATRA耐药的APL细胞系）的作用及机制，并寻找解决APL中ATRA耐药问题的新方法，我们首先分别用IFN-γ、ATRA以及IFN-γ联合ATRA处理NB4和NB4-R1细胞。然后通过MTT法检测细胞增殖情况，并通过光学显微镜、硝基四氮唑蓝（NBT）试验和流式细胞术（FCM）检测细胞分化情况。通过间接免疫荧光试验观察早幼粒细胞白血病（PML）蛋白的表达。结果显示，ATRA抑制NB4细胞的生长，然而，它不能抑制NB4-R1细胞的生长。IFN-γ抑制NB4和NB4-R1细胞的生长。同时，IFN-γ联合ATRA对NB4和NB4-R1细胞的生长抑制作用明显强于任何单一药物治疗。NBT还原试验和FCM检测CD11b抗原的结果表明，IFN-γ在一定程度上诱导NB4和NB4-R1细胞分化。此外，IFN-γ联合ATRA诱导NB4和NB4-R1细胞的成熟程度比单独使用IFN-γ或ATRA更显著。用IFN-γ处理后，NB4和NB4-R1细胞核中荧光颗粒的数量高于对照组，这表明IFN-γ可能诱导PML蛋白的表达。总之，IFN-γ通过增强PML蛋白的表达增强ATRA对NB4和NB4-R1细胞的增殖抑制作用。IFN-γ联合ATRA不仅增强了ATRA对NB4细胞的诱导分化作用，还能部分诱导具有ATRA耐药性的NB4-R1细胞成熟。
