PO.MCB03.02 · 分子与细胞生物学
PTPRF对结肠癌中IL-6/gp130信号传导的调控
The regulation of IL-6/gp130 signaling by PTPRF in colon cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
白细胞介素6(IL-6)水平升高以及IL6/JAK/STAT3信号的激活在促进结直肠癌肿瘤生长和进展中发挥重要作用,使IL-6通路成为潜在的治疗靶点。IL-6的结合刺激形成由IL-6受体及其共受体gp130组成的受体复合物,从而触发JAK家族激酶的激活以磷酸化gp130胞内结构域上的酪氨酸残基。磷酸化的酪氨酸残基作为关键信号组分(包括转录因子STAT3)的对接位点。STAT3与gp130的对接使得JAK能够磷酸化STAT3上的Tyr705,该残基是STAT3二聚化和核转位以促进基因转录所必需的。虽然IL-6通路的磷酸化依赖性激活已被深入研究,但蛋白磷酸酶对信号失活的调控仍在很大程度上未被探索。在此,我们确定了蛋白酪氨酸磷酸酶受体F型(PTPRF)在负向调控控制IL-6/gp130信号传导的酪氨酸磷酸化步骤中的作用。通过CRISPR介导的敲除或多西环素诱导的RNAi在293T和结肠癌细胞中耗竭PTPRF的表达。我们发现PTPRF下调导致gp130总蛋白表达以及基础酪氨酸磷酸化增加。此外,与对照相比,PTPRF敲除细胞中IL-6刺激诱导的Jak家族激酶激活(如Tyr1007/1008磷酸化所示)大幅增加且更持久。此外,共免疫沉淀实验结果显示,PTPRF敲除细胞中STAT3与gp130的结合增加,这与JAK激活增强一致。在功能上,通过RT-qPCR测定,在PTPRF敲低的结肠癌细胞中,IL-6刺激后STAT3靶基因SOCS3的表达显著升高。综上所述,本研究确定PTPRF是结肠癌中IL-6/gp130信号通路的新型调节因子。
查看英文原文 English abstract
Elevated Interleukin 6 (IL-6) levels and the activation of IL6/JAK/STAT3 signaling play an important role in promoting tumor growth and progression in colorectal cancer, making the IL-6 pathway a potential therapeutic target. Binding of IL-6 stimulates the formation of a receptor complex consisting of the IL-6 receptor and its co-receptor, gp130, which triggers the activation of JAK family kinases to phosphorylate tyrosine residues on the intracellular domain of gp130. The phosphorylated tyrosine residues act as docking sites for key signaling components, including transcription factor STAT3. Docking of STAT3 to gp130 allows for the phosphorylation of Tyr705 on STAT3 by JAK, the residue necessary for dimerization and nuclear translocation of STAT3 to promote gene transcription. While the phosphorylation-dependent activation of the IL-6 pathway has been intensively investigated, the regulation of signaling inactivation by protein phosphatases remains largely unexplored. Here we determined the role of protein tyrosine phosphatase receptor type F (PTPRF) in negatively regulating the tyrosine phosphorylation steps that control IL-6/gp130 signaling. The expression of PTPRF was depleted by CRISPR-mediated knockout or doxycycline inducible RNAi in 293T and colon cancer cells. We found that PTPRF downregulation resulted in an increase in total protein expression as well as tyrosine phosphorylation of gp130 basally. Additionally, IL-6 stimulation-induced activation of Jak family kinases, as indicated by Tyr1007/1008 phosphorylation, was largely increased and more sustained in PTPRF knockout cells compared to control. Furthermore, results from co-immunoprecipitation experiments showed that the association of STAT3 with gp130 was increased in PTPRF knockout cells, consistent with increased JAK activation. Functionally, the expression of SOCS3, a STAT3 target gene, was significantly elevated upon IL-6 stimulation as determined by RT-qPCR in PTPRF knockdown colon cancer cells. Taken together, this study identifies PTPRF as a novel regulator of the IL-6/gp130 signaling pathway in colon cancer.
利益披露 Disclosure
H. Stanczyk, None..
C. Galeano-Naranjo, None..
T. Gao, None.