Abstract:

Objective To prepare the nanodrug paclitaxel dimer（PTX₂）-loaded nanoparticles（NPs） using the block copolymer 1，2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol 2000，（DSPE-PEG₂₀₀₀）， and to explore the killing effect of PTX₂ NPs on the human lung cancer A549 cells and its influence on apoptotis. Methods The PTX₂ NPs were prepared using nanoprecipitation method. Dynamic light scattering （DLS） was employed to determine the particle size distribution， and transmission electron microscope （TEM） was used to observe the ultrastructure of the nanoparticles. After treatment of 0 and 10 mmol·L^-1 dithiothreitol （DTT）， dialysis method was used to evaluate the in vitro drug release profile of PTX₂ NPs. The cell counting kit-8（CCK-8） method was used to assess the survival rates of the A549 cells after treated with PTX₂ and PTX₂ NPs with different concentrations （0.000 1， 0.001 0， 0.010 0， 0.100 0， and 1.000 0 μmol·L^-1）. The A549 cells were divided into control group， PTX₂ group， and PTX₂ NPs group.Live/dead staining method was used to detect the survival of the A549 cells in various groups， and flow cytometry was used to detect the apoptotic rates of the A549 cells in various groups. Results The mean hydrodynamic diameter of PTX₂ NPs was determined to be 144.7 nm by DLS. The TEM imaging confirmed uniform spherical morphology of PTX₂ NPs. In a reductive environment， the PTX₂ NPs exhibited continuous drug release with total paclitaxel（PTX） release of 84% within 72 h. The results of CCK-8 method showed that both PTX₂ and PTX₂ NPs inhibited the proliferation of A549 cells in a dose-dependent manner. When the concentrations of PTX<0.01 μmol·L^-1， compared with PTX₂ group，the survival rates of A549 cells in PTX₂ NPs group were significantly decreased （P<0.01 or P<0.001）. The live/dead staining results showed that compared with PTX₂ group，the number of red fluorescence-labeled dead cells in PTX₂ NPs group was increased. The flow cytometry results demonstrated that compared with control group and PTX₂ group，the apoptotic rates of the A549 cells in PTX₂ NPs group were significantly increased （P<0.05 or P<0.01）. Conclusion The PTX₂-loaded nanoparticles PTX₂ NPs are successfully prepared which exhibits responsive drug release and demonstrates a more significant killing effect on the human lung cancer A549 cells compared to PTX₂.

Key words: Paclitaxel dimer, Nanoparticle, Lung adenocarcinoma, Drug delivery, Apoptosis