Objective To evaluate the antitumor efficacy of proliferating cell nuclear antigen antisense oligonucleotide (PCNA-ASO) in combination with recombinant adenovirus p53 (Ad-p53) against bladder cancer EJ and BIU-87 cells in vitro and in vivo. Methods Cells were transfected with Ad-p53 (100 MOI), and PCNA-ASO (1.6 μmol/L) was then introduced into the cells using a cationic lipid (lipofectamine, 20 μl/ml). In vitro and in vivo antitumor effects of combining PCNA-ASO with Ad-p53 were measured using the MTT assay, flow cytometry, clone formation, and a nude mice model. Results The combination of PCNA-ASO and Ad-p53 inhibited cell viability in both the EJ (89.3%) and BIU-87 (78.6%) cell lines. The ability of the cells to form foci was also reduced by 74.8% in EJ cells and by 67.5% in BIU-87 cells (P<0.01). A significant decrease of cells in the S phase (11.4% in EJ cells, 14.6% in BIU-87 cells) and a significant increase of cells in G1 phase (62.2% in EJ, 56.8% in BIU-87) were noted. The mean tumor volume after 7 days of treatment with PCNA-ASO or Ad-p53 in combination decreased to 47.6% or 36.4% of the initial tumor size in the two cell lines respectively. Conclusion These results indicate that combined PCNA-ASO and Ad-p53 in the treatment of bladder cancer with mutant p53 has important therapeutic potential, significantly suppressing the growth of human bladder cancer both in vitro and in vivo. Objective To evaluate the antitumor efficacy of proliferating cell nuclear antigen antisense oligonucleotide (PCNA-ASO) in combination with recombinant adenovirus p53 (Ad-p53) against bladder cancer EJ and BIU-87 cells in vitro and in vivo. Methods Cells were transfected with Ad was introduced into the cells using a cationic lipid (lipofectamine, 20 μl / ml). In vitro and in vivo antitumor effects of combining PCNA-ASO with Ad-PCO-ASO (1.6 μmol / L) Results The combination of PCNA-ASO and Ad-p53 inhibited cell viability in both the EJ (89.3%) and BIU-87 (78.6%) was measured using the MTT assay, flow cytometry, ) cells lines. The ability of the cells to form foci was also reduced by 74.8% in EJ cells and by 67.5% in BIU-87 cells (P <0.01). A significant decrease of cells in the S phase (11.4% in EJ cells, 14.6% in BIU-87 cells) and a significant increase of cells in G1 phase (62.2% in EJ, 56.8% in BIU-87) were noted. The me an tumor volume after 7 days of treatment with PCNA-ASO or Ad-p53 in combination decreased to 47.6% or 36.4% of the initial tumor size in the two cell lines respectively. Conclusion These results indicate that combined PCNA-ASO and Ad-p53 in the treatment of bladder cancer with mutant p53 has important therapeutic potential, significantly suppressing the growth of human bladder cancer both in vitro and in vivo.