EPHB1 Protein Promoted the Progression of Prostate Adenocarcinoma Through Phosphorylating GSK3B and Activating EPHB1-GSK3B-SMAD3 Pathway.

Background: The apoptosis affected the prostate adenocarcinoma (PRAD); we aimed to explore the potential pathogenesis of high-risk patients based on the apoptosis features. Method: The RNA-seq data of patients and apoptosis genes were used for apoptosis score calculation via "GSVA" package; then, the weighted gene coexpression network analysis (WGCNA) and Lasso algorithm were performed for a RiskScore model. After that, the "maftools" package was applied for the somatic mutation analysis. By combining the Kaplan-Meier (KM) survival curves in order to compare the prognosis of different subgroups of patients, Cell Counting Kit-8 (CCK-8), EdU staining, and Transwell assays were performed. Protein expression was measured using western blotting. Finally, the activity of PRAD cells in macrophage polarization was detected using coculture and immunofluorescence assays. Results: The PRAD samples had significantly lower apoptosis scores, and the RiskScore supported the risk stratification of patients. In somatic mutation analysis, EPHB1 and KIF13A from the top six mutant genes were overexpressed in 22RV1 and PC-3 tumor cells, and low levels of EPHB1 indicated a better prognosis. Overexpression or knockdown of EPHB1 affected cell viability, proliferation, and invasion. We found that high expression of EPHB1 interacting with GSK3B protein promoted the expression of p-SMAD3 in 22RV1 cells with high levels of antiapoptotic and invasion markers (BCL2, Snail, and N-CAD). Importantly, GSK3B and EPHB1 knockdown inhibited p-SMAD3 activation and promoted proapoptotic features, accompanied by a reduction in macrophage M2 polarization. Conclusion: This study revealed that EPHB1 plays a pivotal role in activating the EPHB1-GSK3B-SMAD3 pathway to facilitate PRAD progression.