RNF144B-mediated p21 degradation regulated by HDAC3 contribute to enhancing ovarian cancer growth and metastasis

We have shown before that HDAC3 was involved in the pathogenesis of ovarian cancer; however, the specific mechanism of HDAC3 on the pathogenesis of ovarian cancer has not been thoroughly studied. To explore the related proteins in the mechanism of HDAC3 on ovarian cancer. The transcriptome profiles were identified in ovarian carcinoma cells with HDAC3 knockdown or overexpression. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were used to verify transfection efficiency. Immunofluorescence staining were performed to detect the expression levels of HDAC3 and RNF144B in tissues. Cell proliferation, apoptosis, migration and invasion were confirmed by cell counting Kit-8 (CCK-8), terminal deoxynucleotidyl transferase (TUNEL) and transwell assay, respectively. The protein expression of p53, p21, Bax and Bcl-2 was confirmed by western blot, and CoIP assay was used to validate RNF144B/P21/P53 interaction. Meanwhile, the protein synthesis inhibitor cycloheximide (CHX) was performed to treat cells to probe p21 stability. Finally, we established an in vivo tumor model to explore the effects of HDAC3 and RNF144B on tumor growth. Microarray results showed that among the overlapping genes in the two profiles (HDAC3 knockdown and overexpression), RNF144B was decreased or increased in ovarian carcinoma cells with HDAC3 knockdown or overexpression, HDAC3 overexpression promoted RNF144B expression, and HDAC3 knockdown hindered RNF144B levels. The levels of HDAC3 and RNF144B in malignant ovarian cancer were significantly higher than those in normal ovarian tissue and benign ovarian cancer tissue. RNF144B promoted cell proliferation, migration and invasion, and inhibited cell apoptosis. In addition, overexpression of HDAC3 or RNF144B inhibited p53/p21/Bax expression and promoted Bcl-2 expression. Knockout of HDAC3 or RNF144B has the opposite effect, and RNF144B interacted with p21 and regulated the p21/p53 complex degradation, and finally in vivo experiments proved that HDAC3 and RNF144B promoted tumor growth. RNF144B-mediated p21 degradation regulated by HDAC3 contributed to enhancing ovarian cancer growth and metastasis.