p53基因突变和Numb蛋白表达与结直肠癌临床病理学特征及预后的关系

p53 gene mutation and numb expression in colorectal cancer and its clinical significance

目的研究p53基因突变和Numb蛋白表达与结直肠癌患者临床病理因素及预后的关系。方法采用PCR及DNA测序分析60例结直肠癌组织中p53基因突变状况,Western blot检测Numb蛋白的表达,分析p53基因突变状态与Numb蛋白表达水平的相关性;在体外对结肠癌细胞系HCT116(+)和HCT116(-)分别采用基因过表达及RNA干扰,用流式细胞术检测p53基因突变与Numb蛋白表达对结肠癌细胞周期的影响。结果60例结直肠癌组织中31例存在p53基因突变,突变率为52%,外显子(E)5、6、7、8的突变次数分别为5、6、12、11例次。Numb蛋白在p53基因突变组表达水平显著低于非突变组(P=0.009)。Numb蛋白低表达患者的预后比高表达患者的差(P=0.015),其表达水平与结直肠癌的分化程度、淋巴结转移、TNM分期密切相关(均P<0.05)。在两种细胞中转入Numb后其细胞周期均出现G2-M期阻滞,增殖受到抑制,DAPT则具有G1-S期阻滞,二者无明显协同作用。结论结肠癌中p53基因突变状态与Numb蛋白表达密切相关,并影响细胞增殖周期及预后。

Objective to study the mutation of p53 gene in colorectal cancer,analyze the relationship between p53 gene mutation and numb expression pattern,and explore its clinicopathological significance in colorectal cancer.Methods p53 gene mutation in 60 colorectal cancer tissues was analyzed by polymerase chain reaction(PCR)and DNA sequencing,and the expression of numb protein was detected by Western blot.The colon cancer cell lines HCT116(+),HCT116(-)and flow cytometry were used.The survival curve was drawn by Kaplan Meier method.Results p53 gene mutation was found in 31 of 60 tissues(52%),and the mutation times of exons(E)5,6,7 and 8 were 5,6,12 and 11 respectively.The expression level of numb in p53 mutation group was significantly lower than that in non mutation group(P=0.009).The prognosis of patients with low expression of numb(39 cases)was worse than that of high expression of numb(21 cases)(P=0.015).Its expression level is closely related to the degree of differentiation,lymph node metastasis and TNM stage(all P<0.05).After the two cell lines were transferred into numb,the cell cycle appeared G2-M phase arrest and proliferation was inhibited,while dapt had G1-S phase arrest.Conclusion p53 gene mutation related to the expression of numb in colon cancer,which has significant effect on the prognosis.