SPOCD1 Enhances Cancer Cell Activities and Serves as a Prognosticator in Esophageal Squamous Cell Carcinoma

Comprehensive transcriptome analysis has revealed SPOC Domain Containing 1 (SPOCD1) as a potential biomarker for esophageal squamous cell carcinoma (ESCC). However, the expression and oncological roles of SPOCD1 in ESCC remains underexplored. We aimed to evaluate the role of SPOCD1 in oncogenesis and prognosis of ESCC in vitro and in vivoMaterials and Methods: The Cancer Cell Line Encyclopedia (CCLE) database was utilized to evaluate correlations between SPOCD1 expression and oncogenes in ESCC. mRNA and protein levels were measured by qRT-PCR and Simple Western assays, respectively. siRNA-mediated knockdown and overexpression experiments assessed the effects of SPOCD1 expression on proliferation, migration, and invasion of ESCC cell lines. In vivo, siRNA knockdown effects on tumor growth were tested in mouse xenograft models. SPOCD1 mRNA levels in 164 resected tissues were correlated with clinicopathological parameters and survival, while a cohort of 177 patients was analyzed for protein expression and survival.

SPOCD1 mRNA expression varied widely among ESCC cell lines and correlated with epithelial-mesenchymal transition-related genes. Knockdown significantly suppressed proliferation, migration, and invasion (p<0.001), while overexpression increased proliferation (p<0.001). In vivo, siRNA knockdown reduced tumor growth compared to both si-control (p=0.005) and untransfected groups (p<0.001). High SPOCD1 mRNA expression was linked to poor disease-specific survival (p=0.009, HR=1.965, 95% CI=1.187-3.252) and disease-free survival (p=0.047, HR=1.602, 95% CI=1.007-2.549). Similarly, elevated protein levels were associated with unfavorable disease-specific (p=0.013, HR=1.860, 95% CI=1.137-3.041) and disease-free survival (p=0.032, HR=1.618, 95% CI=1.042-2.513).

SPOCD1 expression correlates with the aggressiveness of ESCC cells, and its expression levels in tumor tissues may serve as a prognostic factor for ESCC patients.