[Effect of PLK1 gene silence on cell cycle, proliferation and drug resistance in K562/A02 cells].

The study was purposed to investigate the effect of small interference RNA (siRNA) targeting Polo-like kinase 1 (PLK1) gene on cell cycle progression, proliferation and drug resistance in K562/A02 cells. siRNA plasmid vector specifically targeting PLK1 gene with enhanced green fluorescence protein (EGFP) was transfected into K562/A02 cells. Expressions of PLK1 mRNA and protein were assayed by RT-PCR and Western-blot; cell proliferation was evaluated by direct cell counting after trypan blue staining. Cell cycle and intracellular adriamycin (ADM) accumulation was determined by flow cytometry; 50% inhibition concentration (IC50) of ADM on K562/A02 cells was determined by MTT method. The results showed that, as compared with control cells, siRNA plasmid reduced PLK1 mRNA expression by (34.7 +/- 2.1)% for 24 hours and by (56.6 +/- 1.5)% for 48 hours, PLK1 protein significantly decreased simultaneously by (49.9 +/- 3.2)% and by (62.1 +/- 1.7)%. After being transfected for 24 and 48 hours, the rate of survival cells decreased by 30% and 59% respectively. Forty-eight hours after transfection, the ratio of K562/A02 cells at G2/M increased by 2.77-fold, at the same time, intracellular ADM accumulation increased and the relative efficiency of K562/A02 cells to ADM was 73.8%. It is concluded that PLK1 gene silence can inhibit K562/A02 cell proliferation, induce cell cycle arrest at G2/M, and increase intracellular ADM accumulation, so that enhance cell sensitivity to ADM.