Silver nanoparticles synthesized by Euphorbia hirta exhibited antibacterial activity and induced apoptosis through downregulation of PI3Kγ mediated PI3K/Akt/mTOR/p70S6K in human lung adenocarcinoma A549 cells.

Plant extracts were successfully applied to synthesize nanoparticles, and expected such biological processes of effective for chemotherapeutic applications and safe for human use. Our study planned to evaluate the anticancer efficacy of silver nanoparticles (AgNPs) synthesized by Euphorbia hirta on human lung adenocarcinoma A549 cells. The E. hirta synthesized Eh-AgNPs was investigated by UV-spectroscopy, X-ray diffraction, transmission electron microscopy, and Fourier-transform infrared spectroscopy examination. The bactericidal efficacy of Eh-AgNPs was studied by the agar well method, and the cytotoxicity on A549 cells was assessed by MTT assay. Results showed that Eh-AgNPs exhibited effective antibacterial activity against bacterial pathogens, established dose-dependent cytotoxicity on A549 cells, and persuaded apoptosis, as evidenced by increased lipid peroxidation and decreased levels of antioxidants. Eh-AgNPs significantly increased the early apoptosis in A549 cells in a concentration-dependent way. The Eh-AgNPs administration reduced the Bcl-2 expression; however, it increased the expression of p53, Bax, cleaved caspase-3 and -9 apoptotic members. Eh-AgNPs treatment reduced PI3Kγ, phospho-PI3K, phospho-Akt, phospho-mTOR, and p70S6K levels. The obtained results demonstrated that the Eh-AgNPs induce reactive oxygen species-mediated apoptosis by expressing p53, Bax, and inhibiting PI3K/Akt/mTOR/p70S6K signaling pathway.