Gefitinib对人结直肠癌细胞的生长抑制作用与表皮生长因子受体表达关系的研究

Relationship between antitumor activity of Gefitinib and epidermal growth factor receptor expression in human colorectal cancer cell lines

目的观察表皮生长因子受体（EGFR）酪氨酸激酶抑制剂Gefitinib对人结直肠癌细胞的生长抑制作用,探讨这种作用与结直肠癌细胞EGFR表达的关系。方法应用MTT法检测Gefitinib对6种结直肠癌细胞系的生长抑制效应,求出50%生长抑制剂量IC50;应用反转录半定量PCR（RT-PCR）检测不同结直肠癌细胞中EGFR的mRNA水平;应用Western blotting检测结直肠癌细胞中EGFR及其磷酸化蛋白（p-EGFR）的表达水平。结果Gefitinib在体外抑制结直肠癌细胞生长的IC50值为6.5-172.7μmol/L,以Lovo细胞最为敏感,HT29和SW480为中度敏感,HCT116、LS174和SW620表现为耐药。除SW620细胞以外,其他细胞系均不同程度地表达EGFR mRNA,以Lovo细胞表达最强,与其他细胞系比较差异有统计学意义（P〈0.05）;EGFR蛋白水平检测结果与mRNA相符,Lovo细胞的表达显著高于其他细胞系（P〈0.05）,HT29、SW480、HCT116和LS174T表达差异不明显,SW620几乎不表达;p-EGFR蛋白在Lovo细胞中的表达亦显著高于其他细胞系（P〈0.05）。结论EGFR和p-EGFR的表达与Gefitinib对结直肠癌细胞的生长抑制作用可能存在相关性,EGFR和p-EGFR表达高则细胞对药物的敏感性好,但是EGFR不是决定结直肠癌细胞对Gefitinib敏感性的惟一因素。

Objective To investigate the antitumor activity of Gefitinib, a selected epidermal growth factor receptor-tyrosine kinase inhibitor, on human colorectal cancer cell lines in vitro, and to explore the relationship between the inhibitory effect of Gefitinib on cancer cells and the expression of epidermal growth factor receptor （EGFR）. Methods The growth inhibitory effects of Gefitinib, which expressed as the half growth inhibition dose IC50, on colorectal cancer cells were assessed by MTT assay. EGFR mRNA expression was detected by reverse transcriptional PCR （RT-PCR）. Western blot was used to determine the expression of EGFR protein as well as its phosphorylated forms （p-EGFR）. Results Gefitinib inhibited growth of all the six colorectal cancer cell lines in vitro with an IC50 range from 6.5 to 172.7μmol/L. Lovo cell line, with an IC50 value less than 10μmol/L, was the most sensitive one to Gefitinib, HT29 and SW480 were moderate sensitive to 10μmol/L