肺腺癌SPC-A-1细胞表皮生长因子受体表达水平对其增殖的影响

目的 探讨采用体外化学合成的针对表皮生长因子受体(EGFR)设计的双链RNA(double-stranded RNA，dsRNA)，是否能诱导肺非小细胞肺癌(NSCLC)细胞出现序列特异性基因沉默，及抑制EGFR基因表达后NSCLC细胞的生物学特征。方法 体外合成EGFR序列特异性dsRNA(dsRNA-EGFR)，结合脂质体2000转染肺腺癌SPC-A-1细胞，用荧光显微镜及流式细胞仪测定转染细胞的EGFR受体数量；适时定量聚合酶链反应检测其EGFR基因表达水平。采用集落形成试验检测SPC-A-1细胞的增殖和集落形成能力。建立裸鼠肿瘤模型，计算肿瘤抑制率。结果 dsRNA-EGFR可使EGFR在蛋白水平表达下降71．3％、基因水平表达下降50．0％，SPC-A-1细胞集落形成下降66．8％，并显著抑制在体肿瘤生长，肿瘤抑制率为75．0％。结论 dsRNA-EGFR可序列特异性下调NSCLC细胞EGFR在基因及蛋白水平的表达，有效抑制肿瘤生长。

Antitumor effect of epidermal growth factor receptor gene silencing

Objective To investigate whether chemically synthesized double-stranded RNA(dsRNA) targeting epidermal growth factor receptor(EGFR) could induce gene silencing in non-small-cell lung cancer (NSCLC) cells, and to assess the degree of EGFR gene silencing and its effect on functional outcome. Methods NSCLC cell line SPC-A-1 was transfected with target sequence-specific dsRNA formulated with Lipofectamine 2000. Fluorescent microscopy and flow cytometry were used to measure the reduction in the production of the EGFR protein. Real-time PCR was used to detect the silencing of the EGFR gene level. Colony assay was adopted to measure the cellular proliferation and colony formation. A tumor burdened athymic nude mouse model was established to calculate the tumor growth inhibition rate. Results The dsRNA-EGFR was shown to be effective with a 71.3% down-regulation of EGFR protein production and 50.0% of silencing of EGFR gene. The dsRNA-EGFR significantly reduced colony numbers by 66.8% in vitro and inhibited the tumor growth in vivo. The tumor growth inhibition rate was 75.0%. Conclusion The sequence specific dsRNA showed a blockbuster effect in downregulation of EGFR gene level and protein production, inhibition of the cellular proliferation and tumor growth.