title: Contributors to HMGB1 release by urothelial carcinoma cells in response to bacillus Calmette-Guérin.
abstract: OBJECTIVE
  Our group previously noted that HMGB1 release by urothelial carcinoma cells occurs as a consequence of bacillus Calmette-Guérin induced nonapoptotic cell death. Additional studies demonstrated that HMGB1 release in response to bacillus Calmette-Guérin is required for the in vivo tumor response to bacillus Calmette-Guérin. We evaluated the steps required for HMGB1 release by human urothelial carcinoma cells in response to bacillus Calmette-Guérin exposure.
  
  
  METHODS
  We used the T24 and 253J human urothelial carcinoma cell lines. HMGB1 concentrations in cell culture supernatant with and without bacillus Calmette-Guérin treatment served as the principal end point to assess the role of potentially involved variables. Specific techniques were used to determine the role of α5β1 antigen receptor cross-linking, TLR signaling, inducible nitric oxide synthase expression/nitric oxide production, p21 expression, and bacillus Calmette-Guérin adherence, internalization and viability.
  
  
  RESULTS
  Cross-linking of α5β1 integrin or signaling through TLR2/4 did not contribute to HMGB1 release. Optimal HMGB1 release required bacillus Calmette-Guérin adherence and internalization. Bacillus Calmette-Guérin viability correlated with the magnitude of HMGB1 release. Inhibition of oxidative stress and p21 expression in response to bacillus Calmette-Guérin decreased the magnitude of HMGB1 release.
  
  
  CONCLUSIONS
  Bacillus Calmette-Guérin induced nonapoptotic cell death and HMGB1 release occur as a consequence of a complex multistep process. Understanding the steps and mechanisms involved in the induced HMGB1 release would provide an opportunity for targeted strategies to improve bacillus Calmette-Guérin treatment efficacy.
authors.affiliation: Department of Urology, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Guangjian
authors.initials: G
authors.lastname: Zhang
authors.forename: Fanghong
authors.initials: F
authors.lastname: Chen
authors.forename: Yanli
authors.initials: Y
authors.lastname: Cao
authors.forename: William A
authors.initials: WA
authors.lastname: See
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D001500:BCG Vaccine / Q000494:pharmacology*; D002295:Carcinoma, Transitional Cell / Q000378:metabolism* / Q000473:pathology*; D024243:HMGB1 Protein / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D001500:BCG Vaccine; D024243:HMGB1 Protein
keywords: BCG; BCG vaccine; FN; HMGB1; HMGB1 protein; NO; OD; TLR; UC; bacillus Calmette-Guérin; carcinoma; cyclin dependent kinase inhibitor p21 (cip1/waf1); fibronectin; heat killed BCG; high molecular group box protein 1; hkBCG; iNOS; inducible NO synthase; nitric oxide; optical density; p21; toll-like receptor; urinary bladder; urothelial carcinoma; urothelium