In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparticles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDR1-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope (TEM). MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration (IC50) of paclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control (P<0.05). MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC50 (0.197±0.003, 0.144±0.001, 0.120±0.004) were decreased with difference being significant when compared with that in A2780/TS (0.269±0.003) cells control (P<0.05). It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.
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