CPT1A通过上调p62激活NF-κB信号通路促进食管癌细胞侵袭运动的分子机制研究

Tumor metastasis is one of the major reasons for the deaths of esophageal squamous cell carcinoma (ESCC). Our previous work found that amplification and overexpression of CPT1A were detected in primary ESCC tumors, and significantly associated with lymph node metastasis and poor prognosis respectively. Functional analysis indicated that CPT1A could promote the invasion and migration of ESCC cells by activating NF-κB signaling pathway, and also found that CPT1A positively up-regulated the protein level of p62 via inhibiting ubiquitin-proteasome pathway, and p62 up-regulated the protein level of PKCiota, and p62 and PKCiota were the upstream regulators of NF-κB signaling pathway. In this project, we will further focus on the following aspects: how CPT1A up-regulated the protein level of p62, and revealing the detailed mechanism of CPT1A promoting the invasion and migration of ESCC cells by activating p62/PKCiota/NF-κB signaling pathway; validating the role of CPT1A pathway on tumor metastasis by using the inhibitors such as CPT1A; clarifying the correlation of the expression of key members in CPT1A pathway in primary ESCC tumors, as well as the relationship of these proteins with clinico-pathological parameters and the prognosis of ESCC patients. This project will help provide theoretical foundation for elucidating the mechanisms of the invasion and migration of ESCC cells and tumor metastasis, and provide potential biomarkers and targets for ESCC diagnosis and therapy.

肿瘤转移是导致食管癌患者死亡的重要原因之一。我们前期发现CPT1A在食管癌中异常扩增和高表达，且均与患者的淋巴结转移和不良预后正相关。功能研究发现CPT1A通过激活NF-κB信号通路促进食管癌细胞的侵袭运动；还发现CPT1A抑制泛素-蛋白酶体途径上调p62，p62正调控PKCiota蛋白水平，且p62和PKCiota均位于NF-κB通路上游。本项目将在细胞系、动物模型和食管癌临床标本中进行深入研究，揭示CPT1A如何上调p62，进而调控PKCiota和NF-κB信号通路，最终促进食管癌细胞侵袭运动的详细分子机制；利用CPT1A等分子的抑制剂验证CPT1A通路对食管癌转移的作用；明确食管癌临床标本中CPT1A通路关键分子的异常表达相关性、以及与临床病理参数和预后的关系。本研究将为阐明食管癌细胞侵袭运动和肿瘤转移的分子机制提供理论依据，并为食管癌的诊治提供基于CPT1A通路的分子标志和靶点。

肿瘤转移是导致食管癌患者死亡的重要原因之一，但是目前对于食管癌转移的调控机制还未完全揭示。因此在前期研究工作的基础上，本项目发现在食管癌中CPT1A高表达，且其高表达与拷贝数增加正相关；功能研究发现，敲降CPT1A或采用CPT1A抑制剂Etomoxir（ETO）处理，均显著抑制食管癌细胞的增殖能力、克隆形成能力、迁移和侵袭能力，同时降低食管癌细胞内的ATP水平和分泌的MMPs水平；采用microarray筛选并采用qRT-PCR证实，CPT1A沉默或采用CPT1A抑制剂Etomoxir（ETO）处理均显著下调PLAU的mRNA水平并上调SERPINB2的mRNA水平；分子机制研究发现，CPT1A与去泛素化酶USP14和PKCiota形成蛋白复合体，敲降CPT1A或采用etomoxir抑制CPT1A活性均下调USP14的蛋白水平，并促进PKCiota的自噬降解；沉默CPT1A显著抑制食管癌细胞KYSE510和KYSE450的成瘤能力，并下调肿瘤组织中PLAU的mRNA表达量。我们的研究结果将为开发抗食管癌转移治疗提供新的方法和思路。