HMGB1 and urinary bladder carcinoma: To verify this hypothesis, the effect of TUG1 knockdown on HMGB1 expression in bladder cancer cells was first assessed., qRT-PCR and western blot showed that the mRNA (Fig. 4a) and protein (Fig. 4b and c) levels of HMGB1 were dramatically downregulated in si-TUG1-transfected SW780 and BIU87 cells.