Objective   To investigate the influence of △Np63 gene on the proliferation and apoptosis of transitional cell carcinoma of bladder (TCCB) 5637 cells

and explore its underlying molecular mechanism.    Methods   TCCB 5637 cells were transfected with △Np63-shRNA or control-shRNA expression vector. mRNA and protein levels of △Np63

p27

kip1

and p57

kip2

were measured by RT-PCR and Western bolt analysis

respectively. The cell proliferation was assessed by WST-1 assay

  the change in cell cycle was evaluated by flow cytometry

and cell apoptosis was detected by TUNEL.    Results   The specific shRNA targeted to △Np63 gene downregulated the expression of △Np63 and upregulated the expressions of p27

kip1

and p57

kip2

at mRNA and protein levels. The proliferation of 5637 cells was markedly inhibited and the apoptosis of 5637 cells was increased after transfection eith △Np63-shRNA (P0.05).    Conclusion   △Np63-shRNA effectively inhibits the expression of △Np63

and suppresses cell growth and improves cell apoptosis by upregulating the expressions of p27

kip1

and p57

kip2

.