Zinc oxide nanoparticles mitigate the malignant progression of ovarian cancer by mediating autophagy-dependent ferroptosis.

Background: Previous studies have shown that ZnO-NPs induce autophagy and inhibit the malignant progression of ovarian cancer (OC) cells. This study aims to further explore the mechanism of action of ZnO-NPs on OC.

Methods: SKOV3 cells were treat with different concentrations of ZnO-NPs and cell proliferation was assessed through EDU staining. A Xenograft tumor model was established and mice were treated with varying doses of ZnO-NPs for 21 days. Tumor volume and the weight of each group of mice were measured, and the expression of KI67 in tumor tissues was analyzed to evaluate tumor proliferation in vivo. The expression of autophagy and ferroptosis-related proteins in cells and tumor tissues was examined through immunofluorescence, ELISA, and western blotting assays. The relationship between ZnO-NPs induced autophagy and ferroptosis was further investigated using the ferroptosis inhibitors Fer-1, autophagy inhibitor 3-MA and siRNA for ATG5 (si-ATG5).

Results: ZnO-NPs dose-dependently reduced the proliferation of SKOV3 cells in vitro. In vivo, both high and low doses of ZnO-NPs effectively inhibited the growth of tumor, reduced pathological damage and the expression of KI67 in tumor tissues. Additionally, ZnO-NPs increased the levels of iron, MDA, 4-HNE, oxidized lipid ROS, ATG5, TFR1, ACSL4, LC3, and Beclin1 in cells and tumor tissues, decreased the expression of SOD, GSH-Px, non-oxidized lipid ROS, GPX4, and p62. Transfection with si-ATG5 or treatment with 3-MA significantly weakened these effects of ZnO-NPs in vitro, with si-ATG5 having a stronger weakening effect on the action of ZnO-NPs than 3-MA. However, ferroptosis inhibitor has a lesser impact on the autophagy of ZnO-NPs-treated SKOV3 cells than the effect of autophagy inhibitors and si-ATG5 on the ferroptosis of ZnO-NPs-treated SKOV3 cells.

Conclusion: ZnO-NPs inhibited the malignant progression of SKOV3 cells by inducing autophagy-dependent ferroptosis.