[摘 要] 目的：探究乌头酸酶2（ACO2）发生核转位的条件和作用机制并探讨ACO2核转位对肝癌细胞PLC/PRF/5增殖、迁移和侵袭的影响。方法：借助Human Protein Atlas（HPA）数据库分析ACO2在人肝癌组织中的表达与亚细胞定位；利用NLStradamus网站预测ACO2的潜在核定位信号（NLS），并通过基因截短技术构建NLS缺失的ACO2基因（ACO2 ∆NLS）；将野生型（ACO2WT）及突变型（ACO2ΔNLS）质粒转染至人肝癌PLC/PRF/5细胞，分别在常氧及低氧（1% O₂）条件下培养；采用免疫荧光染色技术，分析低氧条件影响ACO2入核的机制；通过EdU染色、划痕实验及Transwell实验评估PLC/PRF/5细胞的增殖、迁移与侵袭能力；借助WB检测胞核和胞质中ACO2的表达水平以及迁移、侵袭相关蛋白MMP2与MMP9表达水平的变化。结果：HPA数据库分析显示，ACO2在肝癌细胞的细胞核和细胞质中均呈高表达；免疫荧光染色和WB结果显示，低氧能够以NLS依赖的方式显著诱导ACO2发生核转位（均P < 0.01）；功能学实验显示，低氧诱导的ACO2核转位能进一步显著促进PLC/PRF/5细胞的增殖、迁移（均P < 0.05）和侵袭（均P < 0.05）能力。WB实验表明，ACO2核转位可上调迁移、侵袭相关蛋白MMP2与MMP9的表达水平（均P < 0.05）。结论：低氧能以NLS依赖的方式诱导ACO2发生核转位，从而增强PLC/PRF/5细胞的增殖、迁移和侵袭能力。

[Abstract] Objective: To investigate the expression of transgelin (TAGLN) in colorectal cancer (CRC) tissues and its effect on the proliferation, migration and invasion of CRC SW480 cells. Methods: Surgically resected CRC tissues and corresponding para-cancerous tissues of 97 CRC patients from May 2015 to August 2016 in the Affiliated Tumor Hospital of Zhengzhou University were collected; In addition, CRC cell lines SW620, SW480, HCT116 and normal colorectal mucosal cell line FHC were also collected for this study. Immunohistochemical staining was used to detect the expression of TAGLN in CRC tissues, and the correlation between TAGLN and patients’ clinicopathological features was analyzed. Quantitative Real-time quantitative polymerase chain reaction (qPCR) and Western blotting (WB) were used to detect the mRNA and protein expressions of TAGLN in CRC cell lines. si-TAGLN and si-Ctrl were respectively transfected into SW480 cells by liposome transfection method. The effects of silencing TAGLN on the proliferation, migration and invasion of SW480 cells were detected by CCK-8, Wound-healing assay and Transwell assay, respectively; and the expression of EMT-related proteins E-cadherin, N-cadherin and vimentin were detected by WB. Results: The positive expression rate of TAGLN in CRC tissues was significantly higher than that in para-cancerous tissues (P<0.01), and TAGLN expression was correlated with TNM stage, degree of tumor differentiation and lymph node metastasis in CRC patients (P<0.05 or P<0.01). The mRNA and protein expression levels of TAGLN in SW480 cells were significantly higher than those in FHC cells (all P<0.01). After TAGLN silence, the proliferation, invasion and migration ability of SW480 cells were significantly reduced (all P<0.01), the expression level of E-cadherin in SW480 cells was increased, while the expression levels of N-cadherin and vimentin were decreased (all P<0.01). Conclusion: TAGLN is highly expressed in CRC tissues and cells. Silencing TAGLN can inhibit the proliferation, invasion and migration of CRC cells, suggesting that TAGLN plays an important role in the occurrence and development of CRC.