Clinical Correlation of Wnt2 and COL8A1 With Colon Adenocarcinoma Prognosis

Abstract

Wnt2 mRNA is widely expressed in various tumor tissues. Wnt2 overexpression promotes tumor growth, migration, invasion, and metastasis. However, its underlying molecular action mechanisms and clinical implications in colon adenocarcinoma (COAD) remain unclear. mRNA expression data, obtained from tissue samples, and pathophysiological data of 368 COAD patients were obtained from the Cancer Genome Atlas (TCGA) database. Further, Pearson's correlation analysis was performed to explore the correlation between the expression levels of Wnt2 and other genes in the human genome. Subsequently, a protein-protein interaction (PPI) network was constructed for hub gene identification. Overall survival and significance were determined by Kaplan-Meier analysis, and the log-rank test was used to further identify genes with prognostic significance in COAD from GEO datasets (GSE17538 and GSE39582). Subsequently, 158 tissue samples from Affiliated Hospital of Jiangnan University were used for expression verification. Gene set enrichment analysis (GSEA) was performed on high and low Wnt2 expression datasets to identify potential signaling pathways activated in COAD. In all, 10 hub genes associated with Wnt2 were screened by Pearson's correlation analysis and PPI network, with Wnt2 and COL8A1 having significantly poor prognosis by Kaplan-Meier analysis and log-rank test. Furthermore, high expressions of COL8A1 and Wnt2 were associated with poor survival both in TCGA and GEO cohorts. We further found a correlation between the expressions of Wnt2 and COL8A1 in COAD as per immunohistochemical analysis. To further elucidate the underlying molecular mechanisms of Wnt2 in COAD, we searched for pathways enriched in Wnt2 overexpressing datasets by GSEA. Our findings revealed that high Wnt2 levels were significantly associated with extracellular matrix receptor and focal adhesion pathways. Wnt2 expression correlated with COL8A1 expression in COAD; patients with high Wnt2 and COL8A1 expressions had worse survival outcomes. Pathways identified in this study prompt the molecular role of Wnt2 in COAD and provide directions to further elucidate the involved molecular mechanisms in COAD.

Keywords: Wnt2; bioinformatics analysis; collagen type VIII alpha 1 chain; colon adenocarcinoma; prognosis.

Figure 1

Prediction of 10 hub genes related to Wnt2 based on COAD data. (A) Hub genes related to Wnt2 in the protein-protein interaction (PPI) network constructed using the STRING website. (B) Hub genes related to Wnt2 in the heatmap. (C) COL1A1; (D) COL1A2; (E) COL3A1; (F) COL4A1; (G) COL5A1; (H) C0L5A2; (I) COL6A3; (J) COL8A1; (K) COL11A1; and (L) COL12A1.

Figure 2

Screening of survival-related hub genes. (A) The relationship between the expression of Wnt2 and overall survival of colon cancer patients. (B) The relationship between BRAF mutation and overall survival of colon cancer patients.

Figure 3

Prognostic value of Wnt2 and COL8A1 in COAD. (A) Prognostic nomogram for COAD based on clinical features, and Wnt2 and COL8A1 expression levels. (B) Calibration curves for clinical prediction model curves for the association of Wnt2-based prognostic score with clinicopathological variables. (C) Patients with low Wnt2 and COL8A1 expression have a better prognosis compared to patients with high Wnt2 and COL8A1 expressions in the TCGA cohort. (D) patients from GSE17538 cohort. (E) Patients from GSE39582 cohort. (F) Patients from Jiangnan University cohort.

Figure 4

Expression of Wnt2 and COL8A1 in COAD tissues. (A) High expression of Wnt2. (B) Low expression of Wnt2. (C) High expression of COL8A1. (D) Low expression of COL8A1. (E) Analysis of the expression of Wnt2 and COL8A1 in 158 tissue samples. Images are taken at a magnification of 10×.

Figure 5

Gene set enrichment analysis of Wnt2 in COAD datasets. (A) ClusterProfiler analysis found nine significantly enriched signaling pathways. (B) GSEA analysis found eight significantly enriched signaling pathways. (C) The intersection of clusterProfiler analysis and GSEA analysis. (D) ECM-receptor pathway. (E) Focal adhesion pathway.