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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. [ABSTRACT FROM AUTHOR]

Platinum-taxane chemotherapy is the first-line standard-of-care treatment administered to patients with epithelial ovarian cancer (EOC), and faces the major challenge of cisplatin resistance. Aurora Kinase A (AURKA) is a serine/threonine kinase, acting as an oncogene by participating in microtubule formation and stabilization. In this study, we demonstrate that AURKA binds with DDX5 directly to form a transcriptional coactivator complex to induce the transcription and upregulation of an oncogenic long non-coding RNA, TMEM147-AS1, which sponges hsa-let-7b/7c-5p leading to the increasing expression of AURKA as a feedback loop. The feedback loop maintains EOC cisplatin resistance via activation of lipophagy. These findings underscore the feedback loop of AURKA/DDX5/TMEM147-AS1/let-7 provides mechanistic insights into the combined use of TMEM147-AS1 siRNA and VX-680, which can help improve EOC cisplatin treatment. Our mathematical model shows that the feedback loop has the potential to act as a biological switch to maintain on- (activated) or off- (deactivated) status, implying the possible resistance of single use of VX-680 or TMEM147-AS1 siRNA. The combined use reduces both the protein level of AURKA using TMEM147-AS1 siRNA and its kinase activity using VX-680, showing more significant effect than the use of TMEM147-AS1 siRNA or VX-680 alone, which provides a potential strategy for EOC treatment. • TMEM147-AS1 induces lipophagy to promote EOC cisplatin resistance via upregulation of ACC1 and LC3B in the downstream of AURKA. • The feedback loop of AURKA/DDX5/TMEM147-AS1/let-7 has the potential to act as a biological switch to maintain on- (activated) or off- (deactivated) status to affect EOC cisplatin resistance. • The combined use of TMEM147-AS1 siRNA in vivo and AURKA inhibitor VX-680 reduces both the protein level and kinase activity of AURKA, showing more significant effect than the use of TMEM147-AS1 siRNA or VX-680 alone, which provides a potential strategy for EOC treatment. [ABSTRACT FROM AUTHOR]