Effect Of Knockdown Of HMGB1 Expression On Malignant Behaviors And Chemosensitivity Of Bladder Cancer Cell Lines

Objective: To investigate the effect of HMGB1 on malignant biological behaviors and chemotherapy resistance in bladder cancer cells.Methods: Twenty bladder cancer tissues and paired adjacent non-tumor tissues were collected for detecting the expression of HMGB1 by immunohistochemistry.T24 and BIU-87 were transfected with siRNA and divided into several groups,respectively.Cell proliferation was analyzed by CCK8 assay;cell cycle were detected by flow cytometry;migration and invasion abilities of T24 were tested using wound healing test and Transwell chamber assay;LC3 puncta was observed through transmission electron microscopy and confocal microscopy;the expressions of relevant proteins in bladder cancer cells were detected by Western blotting assay.Results: HMGB1 was overexpression in bladder cancer tissues compared with paired adjacent non-tumor tissues(P<0.05).Compared to Blank and NC groups,CCK-8 assay showed knockdown of HMGB1 expression suppressed cell proliferation;flow cytometry prompted knockdown of HMGB1 resulted in an increase in the percentage of cells in G0/G1 phase and decreased gemcitabine-induced apoptosis;scratch and Transwell tests indicated HMGB1 knockdown impaired the migration and invasion abilities of T24 cell line;transmission electron microscopy and confocal microscopy results showed gemcitabine induced less autophagic vacuole after loss of HMGB1.Western blotting showed the expression of E-cadherin was upregulation while expression of N-cadherin、vimentin、MMP-2 、MMP-9、cyclinD1、c-Myc and β-catenin were all downregulation after HMGB1 interfering,meanwhile,loss of HMGB1 facilitated to activate cleaved-caspase 3 and cleaved-PARP stimulated by gemcitabine.Conclusion: HMGB1 could facilitate epithelial-mesenchymal transition to enhance malignant biological behaviors of bladder cancer cells and may involve in resistance to chemotherapy through autophagy regulation.