Guo Haijian, Xia Bing
Department of gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430071, People's Republic of China.
Department of gastroenterology, the Second People's Hospital of Shenzhen, Shenzhen, Guangdong, 518035, People's Republic of China.
BMC Cancer. 2016 Jul 30;16:565. doi: 10.1186/s12885-016-2593-6.
Collapsin response mediator proteins (CRMPs) were originally identified in the nervous system and are involved in neuronal development. Similar to CRMP1, CRMP4 has a shorter transcript encoding a short isoform known as CRMP4a, and a longer transcript encoding a long isoform known as CRMP4b. Previous studies have shown that CRMP4a and CRMP4b exhibit opposing functions in neurite outgrowth. In the present study, we aimed to determine whether CRMP4a and CRMP4b have divergent effects in gastric cancer.
We first analyzed the mRNA and protein expression levels of CRMP4a and CRMP4b in surgical resected specimens, gastric cancer cell lines and normal gastric epithelial cell line GES-1 by quantitative real-time PCR. Open reading frame and CRMP4b shRNA were generated by lentivirus package and stable cells stably expressing CRMP4a open reading frame and CRMP4b shRNA were constructed. Then the roles of CRMP4a and CRMP4b in cell proliferation, cell cycle progression, apoptosis, migration, invasion, and adhesion were determined by cell proliferation assays, flow cytometry analysis, transwell migration and invasion assays, cell Adhesion Assay, and tumorigenicity assays in nude mice, respectively.
CRMP4a expression was lower and CRMP4b expression was higher in tumor tissue samples as compared to paired non-tumor tissue samples. Additionally, CRMP4a expression was lower and CRMP4b expression was higher in gastric cancer cell lines than in the normal gastric epithelial cell line GES-1. CRMP4a overexpression and CRMP4b silencing suppressed cell proliferation in vitro and in vivo. Additionally, CRMP4a overexpression and CRMP4b silencing induced a significant G1-phase arrest and a decrease of the percentage of cells in S-phase. Furthermore, CRMP4a overexpression and CRMP4b silencing inhibited cell migration, invasion, and adhesion. However, neither CRMP4a overexpression nor CRMP4b silencing affected apoptosis.
These results indicate that CRMP4a and CRMP4b have opposite effects on cell proliferation, migration, and invasion in gastric cancer.
塌陷反应介导蛋白（CRMPs）最初是在神经系统中被鉴定出来的，参与神经元发育。与CRMP1类似，CRMP4有一个较短的转录本编码一种被称为CRMP4a的短异构体，以及一个较长的转录本编码一种被称为CRMP4b的长异构体。先前的研究表明，CRMP4a和CRMP4b在神经突生长中表现出相反的功能。在本研究中，我们旨在确定CRMP4a和CRMP4b在胃癌中是否具有不同的作用。
我们首先通过定量实时PCR分析CRMP4a和CRMP4b在手术切除标本、胃癌细胞系和正常胃上皮细胞系GES-1中的mRNA和蛋白表达水平。通过慢病毒包装产生开放阅读框和CRMP4b短发夹RNA（shRNA），并构建稳定表达CRMP4a开放阅读框和CRMP4b shRNA的稳定细胞系。然后分别通过细胞增殖试验、流式细胞术分析、Transwell迁移和侵袭试验、细胞黏附试验以及裸鼠致瘤性试验，确定CRMP4a和CRMP4b在细胞增殖、细胞周期进程、凋亡、迁移、侵袭和黏附中的作用。
与配对的非肿瘤组织样本相比，肿瘤组织样本中CRMP4a表达较低，CRMP4b表达较高。此外，胃癌细胞系中CRMP4a表达低于正常胃上皮细胞系GES-1，而CRMP4b表达高于GES-1。CRMP4a过表达和CRMP4b沉默在体外和体内均抑制细胞增殖。此外，CRMP4a过表达和CRMP4b沉默诱导显著的G1期阻滞，并降低S期细胞百分比。此外，CRMP4a过表达和CRMP4b沉默抑制细胞迁移、侵袭和黏附。然而，CRMP4a过表达和CRMP4b沉默均不影响凋亡。
这些结果表明，CRMP4a和CRMP4b在胃癌细胞增殖、迁移和侵袭方面具有相反的作用。
