The Molecular Mechanism Of High Mobility Group Box1(HMGB1)regulating Gastric Cancer Cell Proliferation And Migration

Objective: HMGB1 was a highly conserved chromosomal binding protein that was highl y expressed in man y t ypes of tumors and participate d in the biological processes of regulating tum or proliferation and metastasis.This stud y aimed to investigate the role of HMGB1 in the proliferation and migration of gastric cancer cells and the underl ying molecular mechanism.Methods: Immunohistochemistry was used to detect the expression of HMGB1 in gastric cancer and adjacent tissues.Western blot was used to detect the expressions of HMGB1 in different gastric cancer cells and gastric epithelial cells.Nuclear cytoplasmic separation was used to detect the distribution of HMGB1 in cytoplasm and nucleus,and ELISA assay was used to detect the release of HMGB1.After transfection with HMGB1 over-expression or interference plasmid,Ed U and clon y formation experiments were used to detect cell proliferation;wound healing and transwell experiments were used to detect cell migration.Western blot was used to detect the expressions of C yclins,MMPs,EMT markers and receptors including RAGE,TLR2 and TLR4.The phosphorylations of Akt-m TOR and ERK-CREB signaling pathways were also determined b y using western blotting.After treatment with RAGE inhibitors FPS-ZM1 and rh HMGB1,the activation of Akt-m TOR and ERK-CREB signaling pathways was detected b y Western blot.Following LY294002,Rapam ycin and U0126(inhibitors of Akt,m TOR and ERK)treatment,the proliferation and migration of HGC-27 cells were detected by Ed U,clon y formation,wound healing and transwell experiments,respectivel y.Results: The expression of HMGB1 in gastric cancer tissues was higher than that in adjacent tissues,however,there was no significant correlation between HMGB1 level and clinical patient information,p>0.05.The expression and release of HMGB1 in different gastric cancer cells were clear higher than that in normal gastric epithelial cells,especially HGC-27 cells.After transfection with HMGB1 over-expression plasmid,up-regulation of HMGB1 promoted the proliferation and migration abilities of HGC-27 cell;upregulated the expression s of Cyclin D1,C yclin E1,MMPs and RAGE receptor;promoted the epithelial-mesench ymal transition;activated Akt-m TOR and ERK-CREB signaling pathways.However,above results showed the opposite changes after transfection with HMGB1 interference plasmid in HGC-27 cells.Pretreatment with RAGE inhibitor FPS-ZM1 attenuat ed rh HMGB1 induced the phosphorylations of Akt-m TOR and ERKsignaling pathways in HGC-27 cells,m TOR and ERK inhibitors significantl y reduced the RAGE expression induced b y rh HMGB1.Akt,m TOR and ERK inhibitors inhibited the proliferation and migration of HGC-27 cells induced b y rh HMGB1.Conclusion: 1.HMGB1 was highly expressed in gastric cancer tissues and cells.2.HMGB1 enhanced the interstitialization of epithelial cells b y up-regulating the expression of cyclin and matrix metalloenzyme,and promote d the proliferation and migration of HGC-27 cells.3.HMGB1 regulated the proliferation and migration of gastric cancer cells through RAGE-mediated Akt and ERK signaling pathways and RAGE-m TOR/ERK feedback loops.