非小细胞肺癌转移瘤基因型变化及耐药性机制研究

Genotype change and mechanism of drug resistance of metastatic non - small cell lung cancer

目的探讨非小细胞肺癌（NSCLC）转移瘤与原位肿瘤基因突变的差异以及耐药性产生的机制。方法实时定量聚合酶链反应（Real-timePCR）检测正常肺组织、非小细胞肺癌原位肿瘤组织与转移灶肿瘤组织中高频突变基因的表达差异；Real-timePCR检测正常肺组织、原位肿瘤细胞和转移灶肿瘤细胞体外传代P5、P10后高频突变基因表达变化，Transwell迁移实验、划痕实验检测各代细胞的迁移能力；用化疗药物处理正常肺组织、原位肿瘤细胞和转移灶肿瘤细胞，扩增3代后检测其高频突变基因表达差异，Transwell迁移实验、划痕实验检测各代细胞的迁移能力。结果Real-timePCR结果显示原位肿瘤组织RBl表达降低（0．72±0．05，P=0．013），转移灶组织RB1（0．75±0．02，P=0．004）与p53（0．23±0．07，P=0．021）表达降低，差异有统计学意义，证明原位肿瘤组织与转移灶组织基因突变有差异；传代后，原位肿瘤细胞与转移灶肿瘤细胞基因突变无变化，Transwell迁移实验和划痕实验结果差异无统计学意义；化疗药处理后，原位肿瘤细胞KRAS表达增加（3．43±0．31，P=0．002），转移灶组织第10号染色体上缺失与张力蛋白同源的磷酸酯酶基因（PTEN）表达降低（0．43±0．25，P=0．015）；迁移能力增强，差异有统计学意义（P=0．048、0．011）。结论NSCLC转移灶肿瘤基因突变与原位肿瘤不同，其是由转移过程造成；化疗可驱动肿瘤细胞产生新基因突变，从而使其具有耐药性。

Objective To investigate the difference of genotype between primary tumor and metastatic tumor and the mechanism of chemoresistance in metastatic non - small cell lung cancer （ NSCLC ）. Methods The mRNA expression level of frequently mutated genes in primary and metastatic tumors was detected by quantitive real-time quantitative polymerase chain reaction （Real -time PCR）. Real-time PCR was applied to the primary tumor （P1） ,culture-expanded P5 and P10 ceils. Scratch and Transwell migration assays were performed to study the migration ability. Cells in different groups were treated with chemotherapeutics. The difference of high frequency mutated gene was detected after three generations. Scratch assays and Transwell migration assays were performed to study the migration ability. Results The Real - time PCR results showed that the RB1 expression （0. 72 ±0.05, （ P =0.013 ） in primary tumor decreased and the expression of RB1 （0. 75 ±0.02, P =0. 004） and p53 （0. 23 ±0.07, P =0. 021 ） in metastatic tumor decreased als0.After expanded, cultured cells didn＇ t show difference in the results of Real -time PCR, Transwell migration assay and scratch assay. When exposed to chemotherapy drugs, the expression of KRAS （ 3.43 ± 0. 31, P = 0. 002 ） increased in primary tumor, phosphatase and tensin homologue deleted on chromosome ten （PTEN） （0. 43±0. 25, P = 0. 015） expression decreased significantly and migration capability was enhanced （P = 0. 048, 0. 011 ）. Conclusion The gene mutation in primary tumor was different with metastatic tumor of NSCLC, which occurred during the invasive process. Cancer cells could produce chemoresistance through inducing novel mutation.