Comprehensive Analysis of Prognostic Value and Immune Infiltration of Src Family Kinases in Hepatocellular Carcinoma

Abstract Background: Src family kinases (SFKs) belong to the non-receptor protein tyrosine kinases family which are generally dysregulated in a variety of tumors. This study aims to thoroughly investigate the mutation status, expression level, prognostic value and relationship with immune infiltration of SFKs in hepatocellular carcinoma (HCC). Methods: TIMER2.0, UALCAN, cBioPortal, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, STRING, GeneMANIA and XIANTAO platform were utilized to analyze differential expression, genetic alteration, prognostic value and immune cell infiltration of SFKs in HCC patients. Furthermore, we used quantitative real-time PCR (qPCR) and western blot analysis to measure SFKs mRNA and protein expression in matching specimens of normal tissue versus HCC. We analyzed the biological effects of overexpressing FYN in Huh7 cells and subcutaneous xenograft tumor model. Results: The mRNA expression levels of LYN, SRC and SRM were elevated in HCC tissues, whereas FYN was reduced. Around 10% genetic alterations rate of SFKs was observed in HCC. The mRNA levels of BLK, BRK, FRK, FYN, LCK, LYN, SRC, SRM and YES were correlated with clinical cancer stage. Elevated FYN mRNA level in HCC was positively correlated with overall survival (OS), while SRC was negatively correlated with OS. The interaction network and functional enrichment analysis implied that SFKs were closely associated with the regulation of immune cells, cell adhesion molecules and signaling pathways involved in tumorigenesis and development. And all SFKs members in HCC were significantly relevant to at least half of the six imune-infiltrating cells, including B cells, macrophages, dendritic cells, neutrophils, CD4+ T cells and CD8+ T cells. Furthermore, we confirmed that the protein expression level of FYN was decreased in HCC patients and human hepatoma cell line. Overexpression of FYN suppressed Huh7 cell proliferation, migration, invasion, and tumorigenesis in xenografts nude mice.Conclusion: Dysregulated FYN and SRC expression in HCC is associated with poor prognosis and might be used as novel potential prognostic biomarkers in HCC patients.