Targeted anticancer effects of Juglone-ZnO nanoparticles via cell cycle arrest and caspase-mediated apoptosis in colon cancer cells

Finding new drugs for adjuvant chemotherapy of colon cancer is of high priority. This study aimed to evaluate the antiproliferative properties and anticancer mechanisms of glucose (C) functionalized and juglone-conjugated zinc oxide (ZnO) nanoparticles (NPs) [(ZnO@C-Juglone NPs)] on a colon cancer cell line (SW480). Physicochemical properties of the NPs were characterized by FT-IR, XRD, TEM, SEM-EDS, TGA, zeta potential and DLS analyses. MTT assay was used to explore the antiproliferative potential of the NPs. Cell cycle analysis and frequency of cell apoptosis and necrosis were determined by flow cytometry. Nuclear alteration and caspase-3 activity following treatment with ZnO@C-Juglone were determined and expression of the CASP8 and CASP9 genes as well as caspase-3 activity was evaluated to explore both intrinsic and extrinsic apoptosis pathways. The FT-IR and XRD analyses confirmed the successful synthesis and structural characteristics of ZnO@C-Juglone NPs, demonstrating the presence of juglone functional groups and the crystalline nature of ZnO. The particles were spherical with a diameter range of 10-90 nm, elemental constituents of C, O, and Zn atoms, a hydrodynamic size of 275.3 nm and a zeta potential of -50.3 mV. ZnO@C-Juglone NPs exhibited dose-dependent cytotoxicity and significantly reduced the viability of cancer cells (IC₅₀ = 71 µg/mL). ZnO@C-Juglone NPs caused cell cycle blockage at the G2/M phase, elevated cell apoptosis and necrosis level, and considerable nuclear alterations. Treatment with NPs induced the CASP8 and CASP9 genes by 5.01 and 2.75-fold, respectively and enhanced caspase-3 activity by 6.18-fold. This work indicates promising anticancer properties of ZnO@C-Juglone, which could be employed in the development of innovative pharmaceuticals against colon cancer.