GRK2 overexpression inhibits IGF1-induced proliferation and migration of human hepatocellular carcinoma cells by down-regulating EGR1

OBJECTIVE To investigate the role and mechanism of G protein-coupled receptor kinase 2(GRK2)involving in hepatocel ular carcinoma(HCC)progression.METHODS Cel Counting Kit 8 and tumor colony formation assay were designed to detect HCC cell proliferation,wound healing assay was to detect HCC migration.The correlation between GRK2 and early growth response-1(EGR1)were detected by RT-PCR and real-time PCR assays.Co-immunoprecipitation and Western blot assay were adopted to detect the relationship between GRK2and insulin-like growth factor 1 receptor(IGF-1R)signaling pathway.RESULTS In this study we find that GRK2plays an inhibition role in IGF1-induced HCC cell proliferation and migration.Overexpression of GRK2 causes a decrease in EGR1 expression,while knockdown of GRK2 leads to the dramatically increase in EGR1 expression in the treatment of IGF1.Through co-immunoprecipitation and Western blot assay,we confirm that GRK2can interact with IGF-1R and inhibiting IGF1-induced activation of IGF1R signaling pathway.Silencing EGR1attenuates GRK2 overexpression-caused inhibition of cell proliferation,tumor colony number and migrationactivity,while overexpressing of EGR1 restores the antiproliferative and migratory effect by GRK2 overexpression in HCCLM3 cells.CONCLUSION Taken together,these results suggest that GRK2 may inhibit IGF1-induced HCC cell growth and migration through down-regulation of EGR1 and indicate that enforced GRK2 may offer a potential therapeutic approach against HCC.