Optimized CoQ10 delivery via ZnO/CuO nanoparticles: greater in vitro cell cycle arrest and in vivo tumor suppression than unformulated coenzyme Q10.

Coenzyme Q10 (CoQ10) displays significant anticancer effects, but its potential medical application suffers from its inability to dissolve in water and low rates of absorption. CoQ10-loaded zinc oxide (ZnO-Q10NPs) and copper oxide (CuO-Q10NPs) nanocomposites were developed through co-precipitation synthesis, which used CoQ10 as both a capping and stabilizing agent. FTIR XRD, SEM/EDX, TEM, and XPS were used to confirm that the particles maintained spherical shapes with particle sizes of approximately 30.5 nm for ZnO-Q10NPs and 15 nm for CuO-Q10NPs. MTT assay against MCF-7, HepG2, and Caco-2 cell lines revealed that ZnO-Q10NPs exhibited the highest potency against MCF-7 breast cancer cells (IC50: 3.65 µg mL-1), outperforming free CoQ10, CuO-Q10NPs, and standard chemotherapeutics, while CuO-Q10NPs showed preferential activity against HepG2 cells (IC50: 9.46 µg mL-1). ZnO-Q10NPs caused MCF-7 cells to enter G0/G1 arrest at 73.7% while also causing both early and late apoptosis together with Bax and Caspase-3 upregulation and Bcl-2 downregulation, and topoisomerase IIβ and NRF-2 and TNF-α and β-catenin pathways. The two formulations achieved hepatorenal biomarker normalization together with antioxidant enzyme activity restoration and IL-6-mediated inflammation reduction. The results demonstrate that ZnO-Q10NPs function as a strong multitargeted nanotherapeutic option for breast cancer, which needs additional clinical evaluation.