Figure 4.

Inhibition of HDACs by TSA attenuates down-regulation of hTERT mRNA expression in differentiated HL60 cells and activates hTERT transcription and telomerase in resting human T cells and fibroblasts. C, Competitor for hTERT fragment; β2-M, β₂-microglobulin, internal control for the RT-PCR. (a) (Left) Competitive RT-PCR for hTERT mRNA in HL60 cells treated with TSA and/or DMSO. HL60 cells were incubated with TSA at various concentrations for 30 min, followed by overnight culture together with DMSO and analysis for hTERT mRNA expression. (Right) Quantitative expression of hTERT mRNA levels based on the signals to the left. D, DMSO; T, TSA. (b) (Left) Competitive RT-PCR for hTERT mRNA in T cells treated with different concentrations of TSA or anti-CD3 and anti-CD28 antibodies. (Right) Quantitative expression of hTERT mRNA levels based on the signals to the left. (c) Telomerase activity in T cells treated with different concentrations of TSA or anti-CD3 and anti-CD28 antibodies. (d) Competitive RT-PCR for hTERT mRNA in normal human fibroblasts treated with TSA.