Preparation Of Orpiment Nanoparticles And Its Anticancer Effect And Investigation Of Its Mechanism In Vitro

[Objects]â‘ To study the preparation technology and characterization of orpiment nanoparticles.â‘¡To study anticancer effect of orpiment nanoparticles on leukemia K562 cells and liver cancer SMMC-7721 cells, compared with that of traditional orpiment.â‘¢To study the molecular mechanism of the effect of orpiment nanoparticles on tumor cells.[Methods]â‘ Orpiment nanoparticles were prepared chemically and characterized by transmission electron microscope (TEM) and energy dispersive spectrometry (EDS).â‘¡Methyl thiazolyl tetrazolium (MTT) assay and flow cytometry (FCM) assay were performed to examine the growth inhibition and the apoptosis of K562 cells and SMMC-7721 cells induced by orpiment nanoparticles in vitro, compared with that of traditional orpiment at various concentrations. Optical microscope and TEM were used to observe cell morphological changes.â‘¢TRAP-PAGE silver stain was used to determine telomerase activity of K562 cells. The expressions of bcl-2 and bax genes of K562 cells were detected using immunocytochemistry (ICC) and RT-PCR technology.[Results]â‘ The self-prepared orpiment nanoparticles were approximately spherical or ellipse, well dispersive and about 20 nm, 60 nm, 80 nm, 140 nm, and 400 nm in diameter. EDS identified that only As2S3 was present.â‘¡Orpiment nanoparticles (60 nm, 80 nm, and 140 nm) greatly inhibited the growth of K562 cells and SMMC-7721 cells and induced their apoptosis, much more effectively than traditional orpiment. MTT showed that the survival ratio of cells treated by orpiment nanoparicles was significantly lower than that of traditional orpiment group at the same concentration and incubation time (P < 0.001). FCM confirmed the cell apoptotic rate of orpiment nanoparicles group was much higher than that of corresponding traditional orpiment group.â‘¢TRAP-PAGE silver stain showed that orpiment nanoparticles markedly inhibited the telomerase activity of K562 cells, with a much better effect than that of traditional orpiment. The result of ICC and RT-PCR implies that orpiment nanoparticles can inhibit expression of bcl-2 protein and bcl-2 mRNA, and can enhance expression of bax protein and bax mRNA, in a concentration-dependendent manner.[Conclusions]â‘ Our research demonstrates that five types of orpiment nanoparticles have been successfully prepared by chemical method for the first time, which average diameter was 20 nm, 60 nm, 80 nm, 140 nm, and 400 nm, respectively.â‘¡Compared with traditional orpiment, orpiment nanopaticles can produce a much better cytotoxic effect on cancer cells by apoptosis.â‘¢The good therapeutic effect of orpiment nanopaticles on cancer cells may attribute to fall of telomerase activity, degradation of bcl-2 gene and upragular of bax gene, which can promote the apoptosis of tumor cells.