Biogenic synthesis of gold nanoparticles using Argemone mexicana L. and their cytotoxic and genotoxic effects on human colon cancer cell line (HCT-15)

BACKGROUND: Nanomedicine has evolved as precision medicine in novel therapeutic approach of cancer management. The present study investigated the efficacy of biogenic gold nanoparticles synthesized using Argemone mexicana L. aqueous extract (AM-AuNPs) against the human colon cancer cell line, HCT-15. RESULTS: Biosynthesis of AM-AuNPs was determined by ultraviolet-visible spectroscopy and further characterized by transmission electron microscopy, X-ray diffraction, and Fourier transition infrared spectroscopy analysis. The cytotoxic activity of AM-AuNPs was assessed by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, whereas genotoxicity was evaluated by the DNA fragmentation assay. The expression of apoptosis regulatory genes such as p53 and caspase-3 was explored through semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting to evidence apoptotic cell death in HCT-15 cells. Biogenic AM-AuNPs inhibited cell proliferation in HCT-15 cell line with a half maximal inhibitory concentration (IC(50)) of 20.53 μg/mL at 24 h and 12.03 μg/mL at 48 h of exposure. The altered cell morphology and increased apoptosis due to AM-AuNPs were also evidenced through nuclear DNA fragmentation and upregulated expression of p53 and caspase-3 in HCT-15 cells. CONCLUSION: The AM-AuNPs may exert antiproliferative and genotoxic effects on HCT-15 cells by cell growth suppression and induction of apoptosis mediated by activation of p53 and caspase-3 genes.