Figure 3
Role of c-Myc in saquinavir activity. A. Representative gel showing the binding of nuclear extracts of Jurkat cells to the oligonucleotide 5’- TCCTGCTGCGCACGTGGGAAGCCCT-3’, containing the downstream “CACGTG” E-Box sequence localized at position −34 of hTERT promoter, 24 h following exposure to saquinavir determined using EMSA. Saquinavir up-regulates the binding of nuclear proteins to the E-Box sequence. B. Graph shows the mean ± SD of the OD obtained from 3 EMSA independent experiments. C. Representative experiment showing the effect of saquinavir on c-Myc transcription factor expression tested on nuclear and cytoplasmic extracts of 2×106 viable Jurkat cells after 24 h of treatment (Western Blot). Quality of nuclear extracts was tested using anti Histone H1 Ab. D. Graphs show the mean ± SD of c-Myc OD values obtained from 3 experiments of and all p values were calculated using Student’s t-test. E. Representative experiment showing the role of c-Myc on saquinavir-mediated hTERT up-regulation. Jurkat cells were transfected with siRNA targeting c-Myc mRNA as described in Material and Methods. c-Myc silencing induces marked down-regulation of c-Myc protein and hTERT which is a target of the transcriptional factor. Saquinavir restores c-Myc and hTERT expression to control levels. F. Pooled results relative to 2 separate experiments of c-Myc silencing. Asterisk indicates p < 0.05.