Up-Regulation Of P21(Waf1/Cip1) By Small Activating Rna Inhibits The In Vitro And In Vivo Growth Of Pancreatic Cancer Cells

Aims and background. To study the inhibitory effect of p21(WAF1/CIP1) activation by saRNA on the growth of human pancreatic cancer cells PANC-1 in vitro and in vivo.Methods and study design. A dsRNA (dsP21) targeting the p21(WAF1/CIP1) gene promoter at position-322 relative to the transcription start site was transfected into PANC-1 cells. Expression of mRNA and protein was evaluated by semiquantitative RT-PCR and Western blotting. Proliferation of PANC-1 cells was measured by the MTT method, and the apoptosis rate was detected by flow cytometry. PANC-1 cells were transplanted subcutaneously in nude mice, and the inhibitory effect of dsP21 on tumor growth was observed.Results. The introduction of dsP21 was shown to efficiently up-regulate expression of the p21(WAF1/CIP1) gene in PANC-1 cells according to the results of RT-PCR and Western blotting (P <0.01, compared with controls). The inhibitory effect on cell proliferation was confirmed by the MTT test (P <0.05, compared with controls). The apoptosis rate of PANC-1 cells treated with dsP21 was significantly higher than that of the control cells (P <0.01). Our experimental data showed that dsP21-mediated up-regulation of p21 expression exerted an apparent growth inhibitory effect on PANC-1 cells in vivo.Conclusions. dsP21 targeting the p21(WAF1/CIP1) gene promoter can specifically up-regulate expression of the p21(WAF1/CIP1) gene in PANC-1 cells. It therefore has a substantially inhibitory effect on cell proliferation in vitro and in vivo and can be used as a new method and material for the gene therapy of pancreatic cancer.