目的：探究羧肽酶A4（ CPA4）促进非小细胞肺癌（NSCLC）细胞增殖、迁移、侵袭和EMT进程的机制及其临床意义。方法：通过IHC和WB法检测2012年2月至2015年12月济南市中心医院收治的105例晚期或转移性NSCLC患者的癌组织及其癌旁组织标本，以及NSCLC细胞中CPA4的表达；c2检验分析CPA4表达与患者临床病理特征之间的关联，Kaplan-Meier法分析CPA4表达与患者OS之间的关系。采用细胞转染的方法分别构建稳定过表达和低表达CPA4的H1299与A549 NSCLC细胞，利用CCK-8法、细胞集落形成实验、划痕愈合实验和Transwell小室实验检测过表达或敲减CPA4后细胞增殖、迁移和侵袭能力的变化。建立裸鼠细胞移植瘤模型和尾静脉-肺转移肿瘤模型，检测过表达CPA4和敲减CPA4表达对在裸鼠体内成瘤和转移的影响，通过WB和IHC法检测移植瘤组织中上皮间质转化（EMT）相关标志物的变化。结果：与癌旁组织和正常肺上皮细胞比较，CPA4在 NSCLC 组织和细胞中均呈高表达（均 P?0.05）；CPA4 高表达 NSCLC 患者的OS显著短于低表达患者（P?0.05），CPA4的高表达更多见于分化差、N2~N3淋巴结受累和TNM Ⅳ期（P?0.05或P?0.01）。过表达CPA4促进H1299细胞而敲减CPA4表达则抑制A549细胞的增殖、迁移和侵袭；过表达CPA4促进裸鼠H1299细胞移植瘤生长和肺的转移；过表达CPA4促进H1299细胞的EMT进程相关分子的变化。结论：NSCLC组织和细胞中CPA4均呈高表达，过表达CPA4可诱导EMT进程促进NSCLC细胞的增殖、迁移和侵袭且与肿瘤进展和预后有关，CPA4是一个预测NSCLC复发、预后及可用于靶向治疗的潜在标志物。

Objective: To explore the mechanism and clinical significance of carboxypeptidase A4 (CPA4) promoting the proliferation,migration, invasion and epithelial-mesenchymal transformation (EMT) progression of non-small cell lung cancer (NSCLC) cells.Methods: IHC and WB were employed to detect the expression of CPA4 in NSCLC tissues and adjacent tissues of 105 patients with advanced or metastatic NSCLC in Jinan Central Hospital from February 2012 to December 2015 and the expression of CPA4 in NSCLC cells. Chi-square test was used to analyze the association between CPA4 expression and the clinicopathological characteristics of the patients. The relationship between CPA4 expression and the overall survival (OS) of the patients was analyzed by Kaplan-Meier method. H1299 and A549 NSCLC cells with stable overexpression and downexpression of CPA4 were constructed by cell transfection.Changes in the cell proliferation, invasion and migration after overexpression and knockdown of CPA4 were detected by CCK-8 assay,cell colony formation assay, scratch healing assay and Transwell assay. Xenograft tumor models and tail vein‐lung metastasis tumor models of nude mice were established to detect the role of CPA4 in tumor tumorigenesis and metastasis in vivo. Changes in the markers of EMT in the tissues of xenografts were detected by WB and IHC. Results: Compared with paracancer tissues and normal lung epithelial cells, CPA4 was highly expressed in cancer tissues and cancer cells (all P?0.05). The OS of NSCLC patients with high CPA4 expression was significantly shorter than that of patients with low CPA4 expression (P?0.05). High expression of CPA4 was more common in poor differentiation, N2-3 lymph node involvement and TNM stage Ⅳ (P?0.05 or P?0.01). Overexpression of CPA4 promoted H1299 cells, while knockdown of CPA4 inhibited the proliferation, migration and invasion of A549 cells. Overexpression of CPA4 promoted the growth of H1299 cell xenograft tumors and lung metastatic tumors in nude mice. Overexpression of CPA4 promoted the changes of EMT process-related molecules in H1299 cells. Conclusion: CPA4 is highly expressed in NSCLC tissues and cells. Overexpression of CPA4 can induce EMT, promote the proliferation，migration and invasion of NSCLC cells and is related to tumor progression and prognosis. CPA4 is a potential biomarker for predicting relapse and prognosis of NSCLC and can be used for targeted therapy.

山东省中医药科学技术研究项目（No.Q2022004)；山东省医药卫生科技发展计划（No.202104080454）；济南市中心医院高层次课题 培育计划青年项目（No.202007018）