SMI-4a treatment of pre–T-LBL down-regulates the level of MYC protein. (A) Human pre–T-LBL cell lines, Jurkat, CEM, and SUPT1 were incubated in the absence of serum with DMSO control (C) or 10μM SMI-4a for 24 hours. The extracts of these cells were evaluated by Western blotting for the expression of MYC. The films were scanned and the levels of MYC protein determined by National Institutes of Health ImageJ software normalized to β-actin expression. The percentage of expression is the ratio of MYC in SMI-4a–treated cells compared with untreated control. The experiment was carried out in triplicate and the error bars show the SD from the mean. (B) The level of MYC after SMI-4a treatment of murine 6812/2 cells was evaluated in an identical fashion as in panel A. The percentage of expression is the ratio of each time point over the control at the 0 time point.