Liu Lin, Zhang Min, Zou Ping, Tian Lei, Liu Fang
Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P. R. China.
Ai Zheng. 2006 Apr;25(4):404-8.
BACKGROUND & OBJECTIVE: Polo-like kinase 1 (PLK1), an important cell cycle regulator, is highly expressed in many types of cancer, and is associated with oncogenesis, treatment effectiveness and prognosis. This study was to investigate the enhancive effect of small interference RNA (siRNA) targeting PLK1 gene on the sensitivity of K562/A02 cells to adriamycin (ADM).
siRNA plasmid vector specifically targeting PLK1 gene with enhanced green fluorescent protein (EGFP) was constructed and transfected into K562/A02 cells. The expression of PLK1 was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The 50% inhibitory concentration (IC50) of ADM on K562/A02 cells was measured by MTT assay. Intracellular ADM accumulation and ADM-induced apoptosis of K562/A02 cells were detected by flow cytometry.
After treatment with PLK1 siRNA, the mRNA and protein levels of PLK1 in K562/A02 cells were decreased by (61.9+/-2.5)% and (65.3+/-2.4)% of control. The relative reverse rate of sensitivity of K562/A02 cells to ADM was 67.8%. The intracellular accumulation of ADM was greatly increased, and ADM-induced apoptosis of K562/A02 cells was elevated from 11.33% to 54.39%.
PLK1 gene silencing could enhance intracellular ADM accumulation in K562/A02 cells, improve sensitivity of K562/A02 cells to ADM, and induce cell apoptosis, therefore, reverse cell resistant to ADM.
Polo样激酶1（PLK1）是一种重要的细胞周期调节因子，在多种癌症中高表达，与肿瘤发生、治疗效果及预后相关。本研究旨在探讨靶向PLK1基因的小干扰RNA（siRNA）对K562/A02细胞阿霉素（ADM）敏感性的增强作用。
构建携带增强型绿色荧光蛋白（EGFP）的特异性靶向PLK1基因的siRNA质粒载体，并转染至K562/A02细胞。采用逆转录-聚合酶链反应（RT-PCR）和蛋白质免疫印迹法检测PLK1的表达。采用MTT法测定ADM对K562/A02细胞的半数抑制浓度（IC50）。通过流式细胞术检测K562/A02细胞内ADM的蓄积及ADM诱导的细胞凋亡。
PLK1 siRNA处理后，K562/A02细胞中PLK1的mRNA和蛋白水平分别下降至对照组的（61.9±2.5）%和（65.3±2.4）%。K562/A02细胞对ADM的相对敏感性逆转率为67.8%。细胞内ADM的蓄积显著增加，ADM诱导的K562/A02细胞凋亡率从11.33%升高至54.39%。
沉默PLK1基因可增强K562/A02细胞内ADM的蓄积，提高K562/A02细胞对ADM的敏感性，并诱导细胞凋亡，从而逆转细胞对ADM的耐药性。
