Preparation of novel (-)-gossypol nanoparticles and the effect on growth inhibition in human prostate cancer PC-3 cells in vitro

The aim of the present study was to investigate the antitumor effects and possible mechanism of (-)-gossypol nanoparticles, loaded with vv polyethylene glycol-maleimide (mPEG-Mal), in vitro. Emulsification-volatilization was used to prepare the loaded (-)-gossypol nanoparticles. The toxicity of blank nanoparticles on human prostate cancer PC-3 cells and human prostate RWPE-1 cells was measured. The antitumor effects of the nanoparticles on PC-3 cells were evaluated by an MTT assay, acridine orange staining and transmission electron microscopy in vitro, and the results were compared with those of free (-)-gossypol. In addition, the mRNA expression levels of Bcl-2 and Bak were measured using semi-quantitative reverse transcription polymerase chain reaction. The growth inhibition activity of the loaded (-)-gossypol nanoparticles was found to be dose- and time-dependent, and similar to the activity of free (-)-gossypol. The nanoparticles induced apoptotic morphological changes on the PC-3 cells, downregulating the mRNA expression level of Bcl-2 and upregulating the mRNA expression level of Bak. Blank nanoparticles exhibited no evident toxicity on PC-3 and RWPE-1 cells at a high dose. Therefore, the mPEG-Mal loaded (-)-gossypol nanoparticles demonstrated a favorable antitumor activity and no toxicity. The nanoparticles were able to induce the apoptosis of prostate cancer cells; thus, may be a potential antitumor nanodrug.