Qi‐En Wang

BNIP3L/BNIP3‐Mediated Mitophagy Contributes to the Maintenance of Ovarian Cancer Stem Cells

ABSTRACTOvarian cancer remains the most lethal gynaecological malignancy, with tumour recurrence and chemoresistance posing significant therapeutic challenges. Emerging evidence suggests that cancer stem cells (CSCs), a rare subpopulation within tumours with self‐renewal and differentiation capacities, contribute to these hurdles. Therefore, elucidating the mechanisms that sustain CSCs is critical for improving treatment strategies. Mitophagy, a selective process for eliminating damaged mitochondria, plays a key role in maintaining cellular homeostasis, including CSC survival. Our study demonstrates that ovarian CSCs exhibit enhanced mitophagy, accompanied by elevated expression of the mitochondrial outer membrane receptors BNIP3 and BNIP3L. Knockdown of BNIP3 or BNIP3L significantly reduces mitophagy and impairs CSC self‐renewal, indicating that receptor‐mediated mitophagy is essential for CSC maintenance. Mechanistically, we identify that hyperactivated NF‐κB signalling drives the upregulation of BNIP3 and BNIP3L in ovarian CSCs. Inhibition of NF‐κB signalling, either via p65 knockdown or pharmacological inhibitors, effectively suppresses mitophagy. Furthermore, we demonstrate that elevated DNA‐PK expression contributes to the constitutive activation of NF‐κB signalling, thereby promoting mitophagy in ovarian CSCs. In summary, our findings establish that BNIP3/BNIP3L‐mediated mitophagy, driven by DNA‐PK‐dependent NF‐κB hyperactivation, is essential for CSC maintenance. Targeting the DNA‐PK/NF‐κB/BNIP3L‐BNIP3 axis to disrupt mitochondrial quality control in CSCs represents a promising therapeutic strategy to prevent ovarian cancer recurrence and metastasis.

Circulating extracellular vesicles protein expression for early prediction of platinum-resistance in high-grade serous ovarian cancer

Abstract Platinum resistance in high-grade serous ovarian carcinoma (HGSOC) portends a poor prognosis. Although initial platinum-based chemotherapy response rates are high, 15-20% of patients demonstrate primary resistance to platinum therapy and almost all patients will develop platinum resistance in the recurrent setting. No predictive or diagnostic biomarkers have been utilized specific to platinum resistance. This study aimed to identify candidate biomarkers for platinum resistance in HGSOC using an extracellular vesicle (EV) based approach. We found differentially expressed and distinct EV proteins, namely TMEM205 and CFH, in patients with platinum-resistant (PR) HGSOC compared to those of platinum-sensitive (PS) patients, utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS). Expression of these EV proteins were validated in patient-derived PR cell lines as well as in clinically relevant mouse models of HGSOC post-platinum therapy. We corroborated these findings using serum samples from patients with PS and PR-HGSOC. Both EV CFH and EV TMEM205 exhibited excellent diagnostic capability for PR as noted by receiver operating characteristic curves with area under the curve values of 0.95 and 0.84, respectively. The high diagnostic performance of TMEM205 and CFH within EVs compared to the relatively poor performance of conventional serum proteins such as Ca125 suggests their robust potential as non-invasive biomarkers for detecting platinum resistance in HGSOC. Furthermore, the ROC curve for the combined biomarker demonstrated excellent diagnostic performance, with an AUC of 0.973, a true positive rate (TPR) of 0.938, and a false positive rate (FPR) of 0.062. Incorporating this multi-protein biomarker panel alongside established biomarkers further enhances diagnostic accuracy. Serum EV CFH and TMEM205 are promising biomarkers for early detection of platinum resistance in HGSOC and may highlight underlying chemoresistance mechanisms, offering potential future therapeutic targets.