Receptor interacting protein kinase 4 promotes cell proliferation, migration, and invasion in ovarian cancer via targeting protein kinase C delta

Receptor interacting protein kinase 4 (RIPK4) has been reported to function as an oncogenic role in several types of cancers. The aim of this study was to evaluate the role of RIPK4 in ovarian cancer (OC) cells and to elucidate the mechanism behind this effect. In this study, the GEPIA database was used to analyze the RIPK4 expressions in OC tissues and overall survival. qRT-PCR and western blot assay were performed to detect the expressions of RIPK4 and protein kinase C delta (PRKCD) in OC cells. In addition, cell proliferation was assessed by CCK-8 and colony formation assay while cell invasion and migration were evaluated by transwell, wound healing and western blot assay. The interaction of RIPK4 and PRKCD was analyzed by the STRING database and the bioGRID database, and verified with co-immunoprecipitation. Herein, we describe that RIPK4 expression was upregulated in OC tissues and cells and was associated with poor overall survival. RIPK4 silencing repressed the proliferation, migration, and invasion of OC cells. Mechanistically, PRKCD was highly expressed in OC cells and was combined with RIPK4. PRKCD was highly positively associated with RIPK4 in OC and was regulated by RIPK4. Moreover, PRKCD overexpression reversed the inhibitory effects of RIPK4 silencing on OC cell proliferation, migration, and invasion. RIPK4 functions as an oncogene in OC cells via at least partially binding to PRKCD, which might represent a novel therapeutic strategy for improving survival for patients with OC.