Abstract 2025: Regulatory role of CDC20 phosphorylation in the onset and progression of endometrial carcinoma

Abstract Background: Phosphorylation is a critical post-translational modification regulating key biological processes. CDC20 is a key regulator in cell cycle control, but its phosphorylation's role in Uterine Corpus Endometrial Carcinoma (UCEC) is not well understood. Methods: We used two datasets from the Clinical Proteomic Tumor Analysis Consortium (CPTAC). PDC000126 was the training set, and PDC000441 was used for validation. Both datasets contained proteomic and phosphoproteomic data. Differentially expressed phosphorylation (DEP) sites were identified. Kinase prediction was performed using a kinase-recognition motif library, and functional enrichment analysis was carried out using GSEA. Results: We identified 7223 phosphorylation sites after filtering samples for data quality. Principal component analysis (PCA) distinguished normal from tumor samples but did not separate early- and late-stage tumors. CDC20(T106) and TRA2A(S100) phosphorylation (pCDC20 and pTRA2A for shot) were significantly upregulated in both early and late-stage tumors compared to normal tissues. No significant differences were found between early- and late-stage tumor phosphorylation levels, suggesting these sites are involved in tumor initiation and remain elevated during progression. pCDC20 was associated with worse survival outcomes, particularly when dichotomized using the 70th percentile as a threshold (HR 7.32, P = 0.022). pTRA2A was not significantly related to survival. Multivariate Cox regression, adjusted for tumor grade, confirmed pCDC20 as an independent prognostic factor. CDC20 protein expression alone was not significantly associated with prognosis, but pCDC20 remained significant after adjusting for protein levels (HR = 37.18, P = 0.025). Kinase prediction identified CDK1 and CDK2 as potential regulators of pCDC20. CDK1/2 expression was positively correlated with pCDC20, and protein interaction analysis confirmed strong interactions between CDC20 and CDK proteins. GSEA showed activation of epithelial-mesenchymal transition (EMT), vasculature development, and cell morphogenesis pathways in the pCDC20 high-phosphorylation group. pCDC20 was validated in the PDC000126 dataset, showing similar trends in early- and late-stage tumors. Correlation between pCDC20 and CDC20 protein was confirmed, as was the association between CDK1/2 expression and phosphorylation. Survival analysis in the validation set indicated poorer prognosis in patients with high pCDC20, which became significant after adjusting for tumor grade (HR 3.28, P = 0.04). Conclusions: CDC20 phosphorylation is a prognostic marker in UCEC, possibly functioning by promotion of vasculature development and cell morphogenesis. Targeting pCDC20 may offer therapeutic potential in UCEC treatment. Citation Format: Wanbao Ding,Jiuqin Lu,Yanfang Zhao,Hui Dai,Feilong Zhao,Ding Zhang,Huan Guo. Regulatory role of CDC20 phosphorylation in the onset and progression of endometrial carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2025.