Wang Linbo, Guo Jufeng, Wang Qinchuan, Zhou Jichun, Xu Chenpu, Teng Rongyue, Chen Yongxia, Wei Qun, Liu Zhi-Ping
Department of Surgical Oncology and Institute of Clinical Medicine, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
J Cancer Res Clin Oncol. 2014 Dec;140(12):1997-2008. doi: 10.1007/s00432-014-1753-9. Epub 2014 Jul 9.
Our previous work identified leucine zipper transcription factor-like 1 (LZTFL1) as a novel tumor suppressor gene, with its expression correlated with survival outcome in gastric cancer (GC) patients. This study focuses on the role of LZTFL1 in GC aggression and metastasis as well as its underlying molecular mechanisms.
LZTFL1 immunohistochemical (IHC) staining on 311 paired normal/cancer tissue arrays were used to reconfirm the clinical significance of LZTFL1 expression. Transwell chamber assays were used to determine migration and invasive ability of GC cells. Gelatin zymography was employed to investigate the matrix metalloproteinases (MMPs) activity in tumor cells. Co-immunoprecipitation and Duolink in situ proximity ligation assay were used to analyze the interaction between LZTFL1 and β-catenin and the cellular localization of the interaction.
IHC results indicated that patients with high LZTFL1 expression had a longer overall survival time (58 months, 95 % CI 28-128 months) than patients with low LZTFL1 expression (27 months, 95 % CI 23-35 months; p < 0.01). The expression level of LZTFL1 is associated with the degree of cell differentiation. LZTFL1 is necessary and sufficient to inhibit the expression of molecular markers associated with epithelial-mesenchymal transition (EMT) and cellular phenotypes associated with tumor cell EMT including the migration, invasion, and the expression and activities of MMPs of tumor cells. LZTFL1 binds β-catenin in the cytoplasm of the cell and inhibited its nuclear translocation.
LZTFL1 suppresses GC cell EMT by inhibiting β-catenin nuclear translocation. Re-expression of LZTFL1 in GC cells may be a potential therapeutic means to prevent GC metastasis.
我们之前的研究确定亮氨酸拉链转录因子样1（LZTFL1）为一种新型肿瘤抑制基因，其表达与胃癌（GC）患者的生存结果相关。本研究聚焦于LZTFL1在GC侵袭和转移中的作用及其潜在分子机制。
对311对正常/癌组织芯片进行LZTFL1免疫组织化学（IHC）染色，以再次确认LZTFL1表达的临床意义。采用Transwell小室实验测定GC细胞的迁移和侵袭能力。利用明胶酶谱法研究肿瘤细胞中基质金属蛋白酶（MMPs）的活性。采用免疫共沉淀和Duolink原位邻近连接实验分析LZTFL1与β-连环蛋白之间的相互作用及其细胞定位。
IHC结果表明，LZTFL1高表达患者的总生存时间（58个月，95%CI 28 - 128个月）长于LZTFL1低表达患者（27个月，95%CI 23 - 35个月；p < 0.01）。LZTFL1的表达水平与细胞分化程度相关。LZTFL1对于抑制与上皮-间质转化（EMT）相关的分子标志物表达以及与肿瘤细胞EMT相关的细胞表型（包括肿瘤细胞的迁移、侵袭以及MMPs的表达和活性）是必要且充分的。LZTFL1在细胞胞质中与β-连环蛋白结合并抑制其核转位。
LZTFL1通过抑制β-连环蛋白核转位抑制GC细胞EMT。在GC细胞中重新表达LZTFL1可能是预防GC转移的一种潜在治疗手段。
