E3连接酶RNF126泛素化降解PTEN促进肺鳞癌细胞转移的分子机制

The prognosis of squamous cell Lung cancer is poor due to no specific targeted therapy. Metastasis is the main death cause of patients with squamous cell Lung cancer. Growing evidence demonstrated that the dysregulation of PTEN/PI3K/AKT pathway plays an important role in the metastasis of squamous cell Lung cancer. However, the mechanisms that account for PTEN inactivation is still unclear. Our preliminary data showed that: (1) E3 ubiquitin ligase RNF126 expression is elevated in squamous cell lung cancer, other that lung adenocarcinoma, and patients with higher expression of RNF126 have a shorter survival time; (2) RNF126 could bind PTEN,and RNF126 overexpression could promote cell proliferation and invasion. Based on these data and literatures, we propose RNF126 activates PI3K/AKT pathway through inducing PTEN ubiquitination and degradation, thus promotes metastasis of squamous cell lung cancer. In the present study, we will establish RNF126 overexpression or knockdown cell line, then utilize cell biological methods and xenograft models to investigate the role of RNF126 in invasion and metastasis of lung squamous carcinoma cells.Moreover, molecular biological experiments such as IP will be used to investigate the mechanism underlying RNF126-mediated inactivation of PTEN. Furthermore, clinical tissues samples will be applied to analyze the correlation between RNF126 expression and clinicopathological characters and prognosis of patients with squamous cell lung cancer. Our study will identify the role of RNF126 in the progression of squamous cell lung cancer, as well as provide new insight into the early diagnosis and targeted therapy of lung squamous cell cancer.

肺鳞癌预后较差，无特定靶点，转移是导致肺鳞癌患者死亡的主要原因。PTEN/PI3K/AKT通路在肺鳞癌转移过程中发挥重要作用，但PTEN失活的机制尚不清楚。我们前期研究发现：1）E3泛素连接酶RNF126在肺鳞癌中表达增高，而腺癌中不高，其高表达预示患者预后差；2）RNF126与PTEN蛋白结合，其过表达显著促进鳞癌细胞增殖和侵袭。因此，我们推测RNF126结合并泛素化降解PTEN蛋白，从而活化PI3K/AKT通路，促进肺鳞癌细胞侵袭和转移。在本研究中，我们将构建下调和上调RNF126的细胞模型，在细胞层面和裸鼠模型上探讨RNF126促进肺鳞癌细胞侵袭和转移的作用；采用免疫共沉淀等分子生物学方法，探讨RNF126失活PTEN的分子机制；通过临床样本分析，检测RNF126与患者临床特征及预后相关性。本研究不仅揭示了RNF126在肺鳞癌中的作用机制，还能为肺鳞癌的早期诊断和靶向治疗提供新靶点。

肺鳞状细胞癌（LUSC）临床预后差，缺乏有效的靶向治疗。跨膜emp24转运蛋白3（TMED3）属于TMED家族，负责细胞内蛋白质的转运。本研究旨在探讨TMED3在LUSC中的临床病理意义和生物学效应。免疫组化（IHC）检测TMED3在LUSC中的表达；功能丧失实验用于研究TMED3对LUSC细胞增殖、凋亡、细胞周期和迁移的影响；通过小鼠异种移植模型评估TMED3基因敲除对体内肿瘤生长的影响；此外，通过RNA测序和Ingenuity Pathway Analysis（IPA）识别TMED3的下游靶点。结果显示，TMED3在LUSC组织中上调，这与病理分级呈正相关；TMED3基因敲除参与调控LUSC细胞功能，如抑制增殖、减少集落形成、诱导凋亡和减少迁移等；TMED3基因敲除诱导LUSC细胞凋亡相关蛋白异常。此外，还发现TMED3基因敲除对细胞迁移的抑制是通过调节EMT实现的，EZR被认为是TMED3调节LUSC进展的潜在目标，抑制EZR可以抑制LUSC的进展，甚至降低TMED3过度表达对LUSC的促进作用。总之，TMED3通过EZR促进LUSC的进展和发展，这可能是LUSC的一个新的治疗靶点。