Study of zinc oxide nanoparticles on epithelial-mesenchymal transition and toxicity of spontaneous monocyte-mediated cytotoxity-7721 cells

To explore the method of studying zinc oxide nanoparticles on the epithelial-mesenchymal transition and toxicity of liver cancer SMMC-7721 cells. Human liver cancer SMMC-7721 cells is stored in 90% FBS+10% DMSO liquid nitrogen. ZnO suspension was prepared, cell viability was assessed using MTT assay, cell apoptosis was analyzed by flow cytometry, and EMT-related proteins were detected by western blotting. Results showed LDH activity increased continuously with the increase in ZnO nanoparticle concentration and exposure time (P < 0.001). Both ATP and SOD activities gradually decreased with the increase in ZnO nanoparticle concentration and exposure time (both P < 0.001). The MTT assay revealed that with the increase in ZnO dose, the proliferation of SMMC-7721 liver cancer cells decreased gradually (P < 0.001), and with the continuous increase in exposure time to ZnO nanoparticles, the reproductive viability of these cells also continued to decline (P < 0.001). The apoptosis rate of SMMC-7721 liver cancer cells increased with the increase in ZnO dose (P < 0.001). Flow cytometry results demonstrated that the apoptosis rate of SMMC-7721 liver cancer cells increased with the continuous prolongation of treatment time (P < 0.001). Western blotting experiments revealed that the concentrations of vimentin, Snail, N-cadherin, and Slugn proteins in SMMC-7721 cells increased significantly, whereas those of E-cadherin and ZO-1 decreased significantly, with the increase in ZnO dose (both P < 0.001). Therefore, ZnO nanoparticles can induce apoptosis of SMMC-7721 liver cancer cells, inhibit cell proliferation and EMT, and can be used as a new nanoparticle carrier for potential treatment of liver cancer.