神经导向分子Semaphorin 5A在人胃癌侵袭和转移过程中作用的研究

Study on the role of axon guidance factor Semaphorin 5A in the invasion and metastasis of human gastric cancer

目的探讨神经轴突导向分子Semaphorin5A表达与胃癌患者临床病理特征的关系及其在胃癌侵袭和转移过程中的作用。方法使用免疫组织化学方法检测Semaphorin5A在171例不同性别、年龄、组织学类型和TNM分期胃癌患者组织中的表达。使用Western印迹方法检测Semaphorin5A在具转移能力的胃癌细胞株（SGC7901和MKN-45）和无转移能力的胃癌细胞株（SNU-1和AGS）中的表达情况。运用RNA干扰技术构建Semaphorin5A—siRNA表达载体并转染胃癌细胞株SGC7901，建立Semaphorin5A稳定低表达的胃癌细胞株，经细胞粘附实验、划痕实验和Transwell小室侵袭实验检测Semaphorin5A基因沉默后对胃癌细胞粘附、运动和侵袭的影响。结果Semaphorin5A表达水平与胃癌分化程度（x2=6．32，P=0．01）、胃癌淋巴结转移（x2=7．68，P=0．01）和远处转移（x2=13．6，P=0．00）有关，与患者年龄（x2=0．21，P=0．79）、性别（x2=1．79，P=0．15）和胃癌浸润深度无关（x2=1．34，P=0．55）。SGC7901和MKN-45细胞株中Semaphorin5A的表达水平明显高于SNU一1和AGS细胞株（P〈0．01）。Semaphorin5A基因表达沉默可抑制胃癌细胞的粘附、运动和侵袭能力。结论Semaphorin5A可能通过提高胃癌细胞粘附、运动和侵袭能力，在胃癌侵袭和转移过程中发挥促进作用。

Objective To explore the correlation between axon guidance factor Semaphorin 5A and clinicopathological features and its role in the invasion and metastasis of gastric cancer. Methods The expression of Semaphorin 5A in gastric cancer tissues of 171 patients with different gender, age, histological type and TNM stage was detected with immunohistochemistry assay. The expression of Semaphorin 5A was determined by Western blotting assay in gastric cancer cell lines SGC7901 and MKN-45 with metastatic ability and gastric cancer cell lines SNU-1 and AGS without metastatic ability. With RNA interfere technique （RNAi）, Semaphorin 5A siRNA expression vector was constructed and transfected into gastric cancer cell line SGC7901. The stable gastric cancer cell line down-expressing Semaphorin 5A was established. The effect of Semaphorin 5A gene silencing on the adhesion, migration and invasion of gastric cancer cell was examined by cell adhesion test, wound healing test and transwell chamber assays. Results The expression level of Semaphorin 5A was correlated with the differentiation degree of gastric cancer （x2 = 6.32, P = 0.01 ）, lymphnode metastasis （x2 =7.68, P=0.01） and distant metastasis of gastric cancer （x2 =13.67, P=0.00）, not correlated with age （x2=0.21, P=0.79）, gender （x2=l. 79, P=0.15） and the depth of gastric cancer invasion （x2 =1.34, P=0.55）. The expression of Semaphorin 5A in cell lines SGC7901 and MKN-45 was significantly higher than that of cell lines SNU-1 and AGS （P〈0.01）. Semaphorin 5A gene silencing significantly suppressed the adhesion, migration and invasion abilities of gastric cancer cells. Conclusion Semaphorin 5A may play a catalytic role in the invasion and metastasis of gastric cancer through increasing the adhesion, migration and invasion abilities of gastric cancer cell.