Zinc-doped copper oxide nanocomposites inhibit the growth of human cancer cells through reactive oxygen species-mediated NF-κB activations

Zinc-doped copper oxide nanocomposites (nZn-CuO NPs) are novel nanparticles synthesized by our group. In the present study, the antitumor effects and the underlying molecular mechanisms of the nZn-CuO NPs were investigated. The cytotoxicity of nZn-CuO NPs against several types of cancer cell lines was studied using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS)/phenazinemethosulfate (PMS) assay. Results showed that nZn-CuO NPs exerted obvious antiproliferation effects on cancer cells and relatively weak antiproliferation effects on normal cells. The antitumor mechanisms of nZn-CuO NPs were further investigated using human liver cancer HepG2 cells and human pancreatic cancer Panc28 cells. Hoechst 33342 staining and FITC-Annexin V/PI staining showed that nZn-CuO NPs could induce cell apoptosis in a dose dependent manner. Cell-cycle analysis using flow cytometry revealed that nZn-CuO NPs were able to arrest the cell cycle in the G2/M phase. Also, nZn-CuO NPs were found to induce reactive oxygen species (ROS) generation. Further studies confirmed that nZn-CuO NPs could increase p-IKKα/β and nucleus p-NF-κB p65 expressions and decrease IKKα, IKKβ, IκBα, and nucleus NF-κB p65 expressions in both cell lines. Overall, our data demonstrated that nZn-CuO NPs could selectively inhibit the growth of cancer cells via ROS-mediated NF-κB activation. The current study provides primary evidence that nZn-CuO NPs possess the potential to be developed as a novel anticancer agent.