KCMF1 promotes malignant progression by NXN ubiquitin-dependent degradation in ovarian cancer

Ovarian cancer, one of the most lethal gynecologic malignancies, exhibits marked tumor heterogeneity. Potassium channel modulatory factor 1 (KCMF1), a RING zinc-finger protein with E3 ubiquitin ligase activity, has been implicated in tumorigenesis. However, the role of KCMF1 in ovarian cancer remains unclear. In this study, we found that KCMF1 was up-regulated in ovarian cancer tissues and that high KCMF1 expression correlated with poor survival of patients. Functional assays revealed that KCMF1 knockdown suppressed cell viability, hampered cell cycle progression, and inhibited proliferation in ovarian cancer cells. Moreover, silencing KCMF1 inhibited epithelial-mesenchymal transition (EMT), migration, and invasion in vitro. In vivo experiments confirmed that KCMF1 knockdown inhibited tumor growth and metastasis in nude mice. Conversely, KCMF1 overexpression had opposite effects in vitro and in vivo. IP-LC/MS and Label-free proteomic analysis identified nucleoredoxin (NXN), a multifunctional redox-active protein, as a potential substrate of KCMF1. Silencing NXN facilitated cell proliferation, migration, and invasion through activating the β-catenin signaling pathway. Mechanistically, we discovered that KCMF1 interacted with NXN and facilitates its degradation through K63-linked ubiquitination, thereby reducing NXN expression. Taken together, our study showed that KCMF1 promotes ovarian cancer progression through NXN, and KCMF1 might be a novel target for ovarian cancer therapy.