Small Double-Stranded RNA Mediates the Anti-Cancer Effects of p21(WAF1/ClP1) Transcriptional Activation in a Human Glioma Cell Line

PURPOSE: This study was conducted to investigate the small double-stranded RNA (dsRNA) mediated anti-tumor effects of p21(WAF1/ClP1) (p21) transcriptional activation in vitro in the human glioma SHG-44 cell line. MATERIALS AND METHODS: Human glioma SHG-44 cells were transfected with dsRNA using LipofectAMINE 2000 transfection reagent. Real-time PCR and Western blot analysis were conducted to detect p21 and survivin mRNA and protein levels, respectively. Cell proliferation was examined by MTT assay. Cell cycle distribution and apoptosis were detected by flow-cytometric analysis. RESULTS: We found that dsRNA targeting p21 promoter (dsP21) significantly induced the expression of p21 at transcription and protein levels, and reduced the expression of survivin. AS well, dsP21 transcription significantly inhibited human glioma SHG-44 cell proliferation. Analysis of cell cycle distribution revealed that dsP21 transfection increased accumulation of cells in the G0/G1 phase and reduced accumulation of cells in the S phase. Further analysis revealed that dsP21 transcription led to an increase in both early and late stages of apoptosis in human glioma SHG-44 cells. CONCLUSION: In the present study, P21 activation by RNA-induced gene activation (RNAa) induced anti-tumor activity in vitro in a human glioma SHG-44 cell line. The results suggested that RNAa could be used for human glioma treatment by targeted activation of tumor suppressor genes.