Ring-Finger Protein 126 (RNF126) Promotes Anoikis Resistance and Peritoneal Colonization in Ovarian Cancer

Ovarian cancer (OC) represents the most lethal gynecologic malignancy because the majority of patients with OC are diagnosed at advanced stages with peritoneal colonization of OC cells owing to subtle and nonspecific nature of symptoms. Thus, peritoneal colonization-directed therapeutic approaches are urgently needed for patients with advanced OC. Here, we investigated whether Ring-finger protein 126 (RNF126), an E3 ubiquitin ligase that is aberrantly upregulated in epithelial OC tissues, contributes to the peritoneal colonization of OC. RNF126-depleted OC cells showed comparable proliferation under normal culture conditions but displayed decreased growth under floating (anchorage-independent) conditions in vitro. Further analyses showed that RNF126 promoted anoikis resistance in vitro and increased peritoneal colonization in immunodeficient mice in a RING domain-dependent manner. Mechanistically, RNF126 activated the transcriptional factor NF-κB in OC cells under floating conditions in a RING domain-dependent manner, and this NF-κB activation was essential for anchorage-independent growth and peritoneal colonization of OC cells. Thus, RNF126 is a possible target for the prevention and/or therapy of peritoneally colonized OC.