Upregulated insulin receptor tyrosine kinase substrate promotes the proliferation of colorectal cancer cells via the bFGF/AKT signaling pathway

BACKGROUND: Some recent studies on insulin receptor tyrosine kinase substrate (IRTKS) have focused more on its functions in diseases. However, there is a lack of research on the role of IRTKS in carcinomas and its mechanism remains ambiguous. In this study, we aimed to clarify the role and mechanism of IRTKS in the carcinogenesis of colorectal cancer (CRC). METHODS: We analysed the expression of IRTKS in CRC tissues and normal tissues by researching public databases. Cancer tissues and adjacent tissues of 67 CRC patients who had undergone radical resection were collected from our center. Quantitative real-time polymerase chain reaction and immunohistochemistry were performed in 52 and 15 pairs of samples, respectively. In vitro and in vivo experiments were conducted to observe the effect of IRTKS on CRC cells. Gene Set Enrichment Analysis and Metascape platforms were used for functional annotation and enrichment analysis. We detected the protein kinase B (AKT) phosphorylation and cell viability of SW480 transfected with small interfering RNAs (siRNAs) with or without basic fibroblast growth factor (bFGF) through immunoblotting and proliferation assays. RESULTS: The expression of IRTKS in CRC tissues was higher than that in adjacent tissues and normal tissues (all P < 0.05). Disease-free survival of patients with high expression was shorter. Overexpression of IRTKS significantly increased the proliferation rate of CRC cells in vitro and the number of tumor xenografts in vivo. The phosphorylation level of AKT in CRC cells transfected with pLVX-IRTKS was higher than that in the control group. Furthermore, siRNA-IRTKS significantly decreased the proliferation rate of tumor cells and the phosphorylation level of AKT induced by bFGF. CONCLUSION: IRTKS mediated the bFGF-induced cell proliferation through the phosphorylation of AKT in CRC cells, which may contribute to tumorigenicity in vivo.