Biogenic synthesized silver nanoparticles using fungal endophyte Cladosporium oxysporum of Vateria indica induce apoptosis in human colon cancer cell line via elevated intracellular ROS generation and cell cycle arrest

Abstract

Green synthesis of metallic nanoparticles has received substantial attention in biomedical sciences. In the current report, silver nanoparticles (AgNPs) were green synthesized usingCladosporium oxysporum (CO)fungal endophyte extract (COAgNPs) isolated from Vateria indica and evaluated their antitumor activities against multiple cancer cells. The formation of COAgNPs was confirmed by UV–Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and EDX analysis. TEM images revealed the spherical shape of COAgNPs with a size of 5–8 nm. In vitro, cytotoxicity investigations of COAgNPs showed dose-dependent anticancer potential against cancer cells HCT-116 with IC50 values of 28.44 µg/mL. We further confirmed that COAgNPs treatment (IC50: 28.44 µg/mL) enhanced intracellular ROS generation by 2–3 fold using DCFH2-DA fluorogenic dye via FACS leading to DNA damage that was also evident from COMET assay. FITC/PI flow cytometry and Dual AO/EB fluorescentimaging revealed an increase in the apoptotic cells in the COAgNPs treated group compared to the control. In gene expression analysis of pro-apoptotic and anti-apoptotic expression of Caspase 3 and Caspase 8, the PCR method was studied to empathize with triggering molecular mechanisms on the HCT-116 cell line. Furthermore, COAgNPs also presented excellent hemocompatibility and in-vitro cytocompatibility (HaCaT cells). Thus, we have categorically demonstrated that exposure of HCT116 cells to COAgNPs resulted in enhanced intracellular ROS, activation of caspase-9, -3, S/G2 phase cell cycle arrest, and apoptosis. In conclusion, it may be suggested that COAgNPs might be used as a potential anticancer agent with further clinical studies.