Tau Aggregation-Dependent Lipid Peroxide Accumulation Driven by the Hsa_circ_0001546/14-3-3/CAMK2D/Tau Complex Inhibits Epithelial Ovarian Cancer Peritoneal Metastasis

Intraperitoneal dissemination is the main method of epithelial ovarian cancer (EOC) metastasis, which is related to poor prognosis and a high recurrence rate. Circular RNAs (circRNAs) are a novel class of endogenous RNAs with covalently closed loop structures that are implicated in the regulation of tumor development. In this study, hsa_circ_0001546 is downregulated in EOC primary and metastatic tissues vs. control tissues and this phenotype has a favorable effect on EOC OS and DFS. hsa_circ_0001546 can directly bind with 14-3-3 proteins to act as a chaperone molecule and has a limited positive effect on 14-3-3 protein stability. This complex recruits CAMK2D to induce the Ser324 phosphorylation of Tau proteins, changing the phosphorylation status of Tau bound to 14-3-3 and ultimately forming the hsa_circ_0001546/14-3-3/CAMK2D/Tau complex. The existence of this complex stimulates the production of Tau aggregation, which then induces the accumulation of lipid peroxides (LPOs) and causes LPO-dependent ferroptosis. In vivo, treatment with ferrostatin-1 and TRx0237 rescued the inhibitory effect of hsa_circ_0001546 on EOC cell spreading. Therefore, based on this results, ferroptosis caused by Tau aggregation occurs in EOC cells, which is not only in Alzheimer's disease- or Parkinson's disease-related cells and this kind of ferroptosis driven by the hsa_circ_0001546/14-3-3/CAMK2D/Tau complex is LPO-dependent rather than GPX4-dependent is hypothesized.