Growth inhibition of human glioma cells by transfection-induced P21 and its effects on telomerase activity

The aim of this study is to investigate the effect of the p21 gene transfec tion on the growth of cultured human glioma cell lines, and analyze the tel omerase activity, and detection of telomerase components in p21 transfectan t. The p21 gene was transfected into human glioma cell lines, U251MG and T98G with our novel liposome. The cell growth was assessed by counting the numbe r of trypan blue-excluding cells in a hemocytometer and flow cytometry anal ysis. The expression of P21 protein and its mRNA were examined by Western a nd Northern blot analysis. The telomerase activity was assayed by TRAP (tel omerase repeat amplification protocol)/TRAP-HPA (hybridization protection a ssay) method qualitatively and quantitatively. The length of telomere was m easured by Southern blot analysis. The expression of telomerase components (hTERT, hTERC and TEP1) were examined by RT-PCR (reverse transcriptase-poly merase chain reaction). The p21 transfectant demonstrated the expression of P21 protein and its mRN A. The p21 transfection of human glioma cells results in growth inhibition and G0/G1 arrest. The p21 transfectant revealed a decrease of telomerase ac tivity and hTERT expression as compared with control cells. These results suggest that p21 transfection induces G0/G1 arrest in human g lioma cells which associates with the reduction in the telomerase activity and hTERT expression.