Objective: To detect the expression level of suppressors of cytokine signaling 3 （SOCS3） in acute lymphoblastic leukemia (ALL), and to observe the effect of over-expresson of SOCS3 in Jurkat cells on the cytotoxicity of NK cells.
Methods: The expression levels of SOCS3 mRNA in peripheral blood mononuclear cells of 20 children with ALL and 20 healthy children (normal control group) were detected by RT-PCR. The peripheral blood NK cells from healthy subjects were selected by immunomagnetic technique, and the purity was detected by flow cytometry. SOCS3 was overexpressed in Jurkat cells infected with lentivirus vector, and SOCS3 mRNA expression was detected by RT-PCR after lentivirus infection. The NK cells were co-cultured with the infected Jurkat, and LDH release method was used to detect the cytotoxicity of NK cells on the infected Jurkat cells. The concentrations of TNF-α and IFN-γ were determined by ELISA. The expression of NKG2D ligands MICA and MICB on the surface of Jurkat cells were detected by flow cytometry. Western blot was used to detect the effect of SOCS3 overexpression on STAT3 phosphorylation in Jurkat cells.
Results: Compared with the control group, the mRNA expression of SOCS3 in the peripheral blood mononucleated cells of ALL children was significantly decreased. The purity of NK cells isolated by flow cytometry could reach more than 70%. The expression of SOCS3 mRNA in Jurkat cells increased significantly after lentivirus infection. Overexpression of SOCS3 in Jurkat cells significantly promoted the killing ability of NK cells and up-regulated the secretion of TNF-α and IFN-γ from NK cells. The results of flow cytometry showed that the expression of NKG2D ligands MICA and MICB on Jurkat cells increased significantly after SOCS3 overexpression. Western blot results showed that overexpression of SOCS3 significantly reduced the phosphorylation level of STAT3 protein in Jurkat cells.
Conclusion: SOCS3 mRNA expression was significantly decreased in ALL patients, and overexpression of SOCS3 may up-regulate the expression of MICA and MICB of NKG2D ligands on Jurkat cell surface through negative regulation of JAK/STAT signaling pathway, thereby promoting the cytotoxic function of NK cells.
题目: 上调急性淋巴细胞白血病中细胞因子信号传导抑制因子3的表达促进NK细胞杀伤活性的机制研究.
目的: 检测细胞因子信号传导抑制因子3（SOCS3）在急性淋巴细胞白血病（ALL）中的表达水平，并探讨NK细胞对过表达SOCS3细胞系Jurkat细胞的杀伤作用.
方法: 采用RT-PCR技术检测20例ALL患儿及20例健康体检儿童（正常对照组）外周血单个核细胞中SOCS3 mRNA表达水平。免疫磁珠分选健康人外周血NK细胞，采用流式细胞术检测其纯度。慢病毒载体感染Jurkat细胞使之过表达SOCS3，RT-PCR检测慢病毒感染后细胞中SOCS3 mRNA表达情况。将NK细胞与Jurkat细胞共培养， LDH释放法检测杀伤活性，ELISA检测TNF-α和IFN-γ浓度。流式细胞术检测过表达SOCS3后Jurkat细胞表面NKG2D配体MICA与MICB的表达。Western blot检测过表达SOCS3对Jurkat细胞中STAT3蛋白磷酸化水平的影响.
结果: ALL患儿外周血单个核细胞中SOCS3 mRNA表达水平较正常对照组显著降低。流式细胞术检测分离NK细胞纯度可达70%以上。慢病毒感染的Jurkat细胞中SOCS3 mRNA表达显著增加。过表达SOCS3的Jurkat细胞可显著促进NK细胞对其杀伤能力，且可上调NK细胞TNF-α和IFN-γ的分泌。流式细胞术检测结果显示，过表达SOCS3后Jurkat细胞表面NKG2D配体MICA与MICB表达水平均显著增加。Western blot结果显示，过表达SOCS3后可显著降低Jurkat细胞中JAK/STAT信号通路中STAT3蛋白的磷酸化水平.
结论: 在ALL中SOCS3 mRNA表达显著降低，而过表达SOCS3可能通过负性调控JAK/STAT信号通路上调Jurkat细胞表面NKG2D配体MICA与MICB的表达，进而促进NK细胞的杀伤能力.
Keywords: JAK/STAT signaling pathway; NK cells; SOCS3; acute lymphoblastic leukemia.