FL118 selectively inhibits human survivin promoter activity and endogenous survivin expression.

<p><b>a</b> and <b>b</b>. FL118 inhibits survivin promoter activity at concentrations as low as 0.1–1 nM. Cancer cells that stably express a full-length survivin promoter (4080 bp)-driven luciferase construct were treated with FL118 for 24 hours at different concentrations as shown, followed by luciferase activity assay. <b>c</b>, <b>d</b> and <b>e</b>. FL118 does not inhibit promoter activity for the genes of p21, DHFR, HTR or TK at 10 nM levels. Sixteen hours after transfection, cells were treated with FL118 (10 nM) for 24 hours, followed by luciferase activity assay. Each bar (<b>a–e</b>) is the mean ± SD derived from independent testing (N = 3) of at least triplicates. <b>f</b> and <b>g</b>. FL118 inhibits endogenous survivin expression but does not inhibit expression of endogenous p21 and DHFR proteins. Representative results are shown. Subconfluent EKVX (<b>f</b>) and HCT-8 (<b>g</b>) cells were treated with and without FL118 for 24 hours, then cell lysates were analyzed by Western blot. Actin expression was used as an internal control. Quantification: <b>f.</b> %Control: 100, 32, 15 for survivin; 100, 255, 165 for p21; and 100, 91, 97 for DHFR. <b>g.</b> %Control: 100, 48, 32 for survivin; 100, 95, 99 for p21; and 100, 101, 112 for DHFR.