Cancer cells develop resistance to chemotherapeutic intervention by excessive formation of stress granules (SGs), which are modulated by an oncogenic protein G3BP2. Selective control of G3BP2/SG signaling is a potential means to treat non-small cell lung cancer (NSCLC). Co-immunoprecipitation was conducted to identify the interaction of MG53 and G3BP2. Immunohistochemistry and live cell imaging were performed to visualize the subcellular expression or co-localization. We used shRNA to knock-down the expression MG53 or G3BP2 to test the cell migration and colony formation. The expression level of MG53 and G3BP2 in human NSCLC tissues was tested by western blot analysis. The ATO-induced oxidative stress model was used to examine the effect of rhMG53 on SG formation. Moue NSCLC allograft experiments were performed on wild type and transgenic mice with either knockout of MG53, or overexpression of MG53. Human NSCLC xenograft model in mice was used to evaluate the effect of MG53 overexpression on tumorigenesis. We show that MG53, a member of the TRIM protein family (TRIM72), modulates G3BP2 activity to control lung cancer progression. Loss of MG53 results in the progressive development of lung cancer in mg53-/- mice. Transgenic mice with sustained elevation of MG53 in the bloodstream demonstrate reduced tumor growth following allograft transplantation of mouse NSCLC cells. Biochemical assay reveals physical interaction between G3BP2 and MG53 through the TRIM domain of MG53. Knockdown of MG53 enhances proliferation and migration of NSCLC cells, whereas reduced tumorigenicity is seen in NSCLC cells with knockdown of G3BP2 expression. The recombinant human MG53 (rhMG53) protein can enter the NSCLC cells to induce nuclear translation of G3BP2 and block arsenic trioxide-induced SG formation. The anti-proliferative effect of rhMG53 on NSCLC cells was abolished with knockout of G3BP2. rhMG53 can enhance sensitivity of NSCLC cells to undergo cell death upon treatment with cisplatin. Tailored induction of MG53 expression in NSCLC cells suppresses lung cancer growth via reduced SG formation in a xenograft model. Overall, these findings support the notion that MG53 functions as a tumor suppressor by targeting G3BP2/SG activity in NSCLCs.

中文翻译：

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MG53 通过调节非小细胞肺癌中 G3BP2 活性抑制肿瘤进展和应激颗粒形成

癌细胞通过过度形成应激颗粒（SG）而对化疗干预产生抵抗力，应激颗粒由致癌蛋白 G3BP2 调节。选择性控制 G3BP2/SG 信号传导是治疗非小细胞肺癌 (NSCLC) 的潜在手段。进行免疫共沉淀以确定 MG53 和 G3BP2 的相互作用。进行免疫组织化学和活细胞成像以可视化亚细胞表达或共定位。我们使用shRNA敲低MG53或G3BP2的表达来测试细胞迁移和集落形成。通过蛋白质印迹分析检测人NSCLC组织中MG53和G3BP2的表达水平。ATO诱导的氧化应激模型用于检测rhMG53对SG形成的影响。Moue NSCLC 同种异体移植实验在野生型和转基因小鼠（MG53 敲除或 MG53 过表达）上进行。小鼠人非小细胞肺癌异种移植模型用于评估 MG53 过表达对肿瘤发生的影响。我们发现 MG53 是 TRIM 蛋白家族 (TRIM72) 的成员，可调节 G3BP2 活性以控制肺癌进展。MG53 的缺失会导致 mg53-/- 小鼠逐渐发展为肺癌。血流中 MG53 持续升高的转基因小鼠在小鼠 NSCLC 细胞同种异体移植后表现出肿瘤生长减少。生化检测揭示了 G3BP2 和 MG53 通过 MG53 的 TRIM 结构域之间的物理相互作用。敲低 MG53 可增强 NSCLC 细胞的增殖和迁移，而敲低 G3BP2 表达可降低 NSCLC 细胞的致瘤性。重组人MG53 (rhMG53)蛋白可以进入NSCLC细胞诱导G3BP2的核翻译并阻断三氧化二砷诱导的SG形成。rhMG53 对 NSCLC 细胞的抗增殖作用因 G3BP2 敲除而被消除。rhMG53 可以增强 NSCLC 细胞在顺铂治疗后发生细胞死亡的敏感性。NSCLC 细胞中 MG53 表达的定制诱导通过减少异种移植模型中 SG 的形成来抑制肺癌生长。总的来说，这些发现支持了 MG53 通过靶向 NSCLC 中的 G3BP2/SG 活性作为肿瘤抑制因子的观点。