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

<b>Background:</b> The apoptosis affected the prostate adenocarcinoma (PRAD); we aimed to explore the potential pathogenesis of high-risk patients based on the apoptosis features. <b>Method:</b> 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. <b>Results:</b> The PRAD samples had significantly lower apoptosis scores, and the RiskScore supported the risk stratification of patients. In somatic mutation analysis, <i>EPHB1</i> and <i>KIF13A</i> from the top six mutant genes were overexpressed in 22RV1 and PC-3 tumor cells, and low levels of <i>EPHB1</i> indicated a better prognosis. Overexpression or knockdown of <i>EPHB1</i> affected cell viability, proliferation, and invasion. We found that high expression of <i>EPHB1</i> interacting with GSK3B protein promoted the expression of <i>p-SMAD3</i> in 22RV1 cells with high levels of antiapoptotic and invasion markers (<i>BCL2</i>, <i>Snail</i>, and <i>N-CAD</i>). Importantly, <i>GSK3B</i> and <i>EPHB1</i> knockdown inhibited <i>p-SMAD3</i> activation and promoted proapoptotic features, accompanied by a reduction in macrophage M2 polarization. <b>Conclusion:</b> This study revealed that <i>EPHB1</i> plays a pivotal role in activating the EPHB1-GSK3B-SMAD3 pathway to facilitate PRAD progression.