Apoptotic effects of Phlomis armeniaca mediated biosynthesized silver nanoparticles in monolayer (2D) and spheroid (3D) cultures of human breast cancer cell lines

The purpose of current research was to assess the apoptotic effects of biofabrication silver nanoparticles (AgNPs) mediated by the aqueous extract of Phlomis armeniaca on human breast cancer cells (MCF-7 and MDA-MB-231) in monolayer (2D) and spheroid (3D) cultures. The biosynthesized AgNPs were characterized by UV–Vis spectrophotometer (the peaks of resonances at 432 nm), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). 1–20 µM/mL AgNPs were applied to MCF-7 and MDA-MB-231 cell lines to determine IC 50 values at 24, 48 and 72nd h and were found to be 10 µM/mL for both cell lines. Immunohistochemical staining results of BrdU, TUNEL, caspase-3 and Endo G in both 2D and 3D cultures and gene expression levels of caspases (caspase-3, -8 and -9) and Endo G were evaluated. Moreover, the total oxidant/antioxidant status (TOS–TAS) due to AgNPs application in both cell culture mediums was evaluated. AgNPs treatment results in both cell lines in both 2D and 3D cultures showed a significant decrease in the BrdU labeling index, while large amounts of cells were labelled with TUNEL and Endo G. In 2D culture, Endo G expression increased in MCF-7 cells at 48 and 72nd hours, while it increased significantly in MDA-MB-231 cells at all hours. OSI results show that ROS production is increased in cell medium treated with AgNPs. In conclusion, AgNPs mediated by Phlomis armeniaca , synthesized by a green method, successfully induced damage to mitochondria, resulting in cell cycle arrest and consequent cell proliferation blockade and death in both MCF-7 and MDA-MB-231 cells.