人肺癌EGFR基因突变与Gefitinib耐药相关性研究

Relationship between Mutations of the Epidermal Growth Factor Receptor Gene and Drug-Resistance to Gefitinib in Human Lung Cancer in vitro

背景与目的以人肺癌细胞株PC9及其耐药子系细胞PC9/AB2、PC9/AB11、PC9/BB4为模型,观察4株细胞对Gefitinib的耐药差异及耐药机制。方法体外培养细胞测定耐药指数,对4株细胞EGFR基因exon18-21进行测序并在mRNA水平上的测定表达量差异。结果PC9及其3株耐药子系细胞均存在耐药性差异。PC9及其3株耐药子系细胞均存在19外显子15bp缺失突变并且耐药细胞株PC9/AB11外显子20存在A→G的点突变。敏感细胞株PC9的EGFR基因在mRNA水平上的表达量明显高于其他3株耐药株。结论PC9、PC9/AB2、PC9/AB11和PC9/BB4肺癌细胞株对Gefitinib的耐药性存在非常显著的差异,4株肺癌细胞株EGFR基因突变和mRNA表达水平的差异与其与Gefitinib获得性耐药有关。

Background and objective To explore cell lines＇ difference of drug-resistance to gefitinib and the underlying mechanism. Methods Human lung cancer cell lines of PC9, PC9/AB2, PC9/AB11, PC9/BB4 were treated in vitro, exons 18-21 of EGFR gene were sequenced and EGFR gene mRNA levels were measured. Results Four cell lines＇ drug resistance difference of gefitinib were validated. All the four cell lines had the 15 bp deletion at exon 19, and AB11 had A to G point-mutation at exon 20. PC9 EGFR gene in the sensitive cell line was expressed much higher than that in 3 resistance cell lines by real-time PCR. Conclusion There is significant difference of drug-resistance to gefitinib existed among the lung cancer cell lines PC9, PC9/AB2, PC9/AB 11 and PC9/BB4. The mutations changes of expressive level of EGFR gene might be correlated with the acquired drug-resistance to gefitinib in lung cancer cell lines.