The Role And Mechanism Of RasGRP1 In The Development Of Inflammation-Contributed Cancer

Objectives: In our previous study we found that the expression of RasGRP1 was significantly up-regulated in acute inflammatory response.It has been reported that RasGRP1 can restrict the growth of colon cancer cells by opposesing proliferative EGFR-SOS1-Rassignals.Considering acute inflammation rarely leads to tumorigenesis,we hypothesized that RasGRP1 might play an important role in preventing tumorigenesis during acute inflammation.The main purpose of this study is to investigate the role and molecular mechanism of RasGRP1 in inflammation-related tumors.Materials and Methods: Quantitative PCR was used to detect the expression level of EGF,EGFR,SOS1,SOS2 and RasGRP1 genes in HepG2 cells and Huh7 cells.Human RasGRP1 gene was cloned and linked to p3×Flag-CMV vector,and confirmed by sequencing.Western blot was used to detect the effect of overexpression of RasGRP1 gene in Huh7 cells transfected with RasGRP1 expression plasmid for 48 h.The effect of RasGRP1 on the proliferation of Huh7 cells was detected by CCK8 assay and scratch assay.The effect of RasGRP1 on the activation of EGFR signaling pathway was detected by Western blot.Microarray analysis of liver cancer tissue was used to detect the expression of RasGRP1 in HCC and paracancerous tissues.Bioinformatics was used to analysed the effect of RasGRP1 gene expression on the survival of multiple kinds of cancer patients according to the Kaplan-Meier Plotter database(http://kmplot.com/analysis/).Results: We found that RasGRP1 inhibited the proliferation of Huh7 cells mainly by limiting EGFR-SOS1-Ras-AKT signaling pathway.The result of immunohistochemical staining for RasGRP1 on a human liver cancer tissue microarray showed that the high expression of RasGRP1 is positively correlated with the prognosis of liver cancer patients.The liver cancer patients with upregulated RasGRP1 expression had a significantly smaller tumour size and lower γ-glutamyl transferase and longer total survival than the liver cancer patients with downregulated RasGRP1 expression.The analysis of the effect of RasGRP1 gene expression on the survival of multiple kinds of cancer patients according to the Kaplan-Meier Plotter database showed that high expression of RasGRP1 positively correlated with an improved overall survival of many kinds of inflammation-associated cancer patients.Conclusion: RasGRP1 inhibits the proliferation and migration of liver cancer cells by inhibiting the EGFR-Ras-SOS1-AKT signaling pathway;among patients with inflammatory tumors,the expression of RasGRP1 is positively correlated with the prognosis of patients;among patients with non-inflammatory tumors,RasGRP1 has no significant effect on the prognosis Correlation.