Background: Colorectal cancer (CRC) is one of the main causes of cancer-related death worldwide. Stanniocalcin 2 (STC2), a secreted glycoprotein, has been suggested to exert various functions in progression of many cancers. However, the precise biological role in CRC is not fully understood. Therefore, this study based on several public datasets aims at investigating the roles of STC2 in CRC.
Methods: We used The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to evaluate the STC2 expression and its clinical significance in CRC. Cell migration and invasion by STC2 overexpression and knockdown were assessed using Transwell migration and Matrigel invasion assays. We next performed RNAseq analysis on SW480 cells with or without STC2 overexpression. Differentially expressed genes were selected by using fold-change >5 and P-value <0.05.
Results: In this study, we found that STC2 level was significantly higher in CRC than that in adjacent noncancerous tissues from TCGA and GEO. Tumors with high mRNA levels of STC2 were more common in patients with rectal cancer, left-sided CRC, advanced T-stage (T3-T4), positive lymph node involvement and advanced AJCC-stage (III-IV) from TCGA. STC2 displayed the negative correlation with the expressions of epithelial cell markers, while it was positively correlated with the expressions of mesenchymal cell markers, MMPs and the epithelial-mesenchymal transition (EMT)-related transcriptional factors. Furthermore, we found that STC2 promoted cell migration and invasion in vitro. And a group of differentially expressed genes, which were modulated by STC2, were identified from RNAseq analyses.
Conclusion: Our study demonstrates that STC2 is overexpressed in CRC compared with normal tissues, and promotes CRC cell migration and invasion. Our data suggest that STC2 may be used as a potential biomarker for clinical application and target therapy in future.
Keywords: RNAseq; TCGA; colorectal cancer; stanniocalcin 2.