Objective:To detect the effects of Polyporus polysaccharide(PPS),Bacillus Calmette-Guerin (BCG),and their combination on the nuclear factor kappa B(NF-κB)signaling pathway associated-gene expression and investigate the molecular mechanisms of the toxic-reducing effect of PPS in coordination with BCG against bladder cancer.Methods:After T739 cells were treated with PPS,BCG and their combination, the changes in mRNA and protein expression of inhibitor of kappa B kinase beta(IKKβ),NF-κB subunit p65 (NF-κB p65),intracellular adhesion molecule 1(ICAM1)and chemokine(C-c motif)ligand 2(CCL2)in bladder cancer cell line T739 were determined by relative quantitative real-time PCR,Western blot,and flow cytometry (FCM).NF-κB p65 DNA-binding activity in T739 cell was detected by biotinylated probe-ELISA,and NF-κB p65 nuclear expression in T739 cell was observed by immunohistochemistry.Results:Compared with the T739 control group,the mRNA expression of IKBKB(IKKβ),Rel A(NF-κB p65),ICAM1 and CCL2 in T739 cells treated with BCG were increased obviously(Ratio2.0),as well as the expression of IKKβ,CCL2 and ICAM1 proteins.Meanwhile,NF-κB p65 DNA-binding activity and NF-κB p65 nuclear expression in T739 cells treated with BCG were up-regulated significantly(P0.05).Compared with the control,the increased expression in T739 cells were simultaneously down-regulated after PPS treatment,except for ICAM1 protein expression.With cells treated with a combination of BCG and PPS,the expression of genes associated with the NF-κB signaling pathway,such as IKBKB,ICAM1 and CCL2,were all down-regulated compared to the BCG group,as well as Rel A mRNA expression,NF-κB p65 DNA-binding activity and NF-κB p65 nuclear expression.Conclusions: PPS could inhibit the over-activation of the NF-κB signaling pathway induced by BCG in bladder cancer cells and accordingly attenuate the adverse reactions to BCG therapy.