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

Abstract

Src family kinases (SFKs) belong to the non-receptor protein tyrosine kinase family and are generally dysregulated in a variety of tumors. This study aimed to thoroughly investigate the mutation status, expression level, prognostic value and relationship with immune infiltration of SFKs in hepatocellular carcinoma (HCC). TIMER2.0, UALCAN, cBioPortal, Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan-Meier Plotter were used to analyze the 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 (WB) analysis to measure SFKs mRNA and protein expression in matching specimens of normal tissue and HCC. We analyzed the biological effects of FYN in Huh7 cells and subcutaneous xenograft tumor model. We also studied the biological effects of SRC on Huh7 cells. The mRNA expression levels of LYN, SRC and SRM were elevated in HCC tissues, whereas FYN was reduced. Approximately 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 levels in HCC were positively correlated with overall survival (OS), whereas SRC was negatively correlated with OS. All SFKs members in HCC were significantly associated with at least half of the six immune-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 patients with HCC and in a human hepatoma cell line. Overexpression of FYN suppressed Huh7 cell proliferation, migration, invasion, and tumorigenesis in xenograft nude mice. Knockdown of SRC inhibited Huh7 cell proliferation, migration and invasion. Dysregulated FYN and SRC expression in HCC is associated with poor prognosis and may be used as novel prognostic biomarkers in patients with HCC.