KJ Pyr 9 is a cell-permeable inhibitor of c-Myc (Kd = 6.5 nM) that interferes with Myc-Max complex formation in cells. It preferentially blocks the proliferation of c-Myc-overexpressing cells, reducing Myc-driven gene expression. KJ Pyr 9 also potently blocks cell growth directed by overexpression of v-Myc, while less effectively blocking N-Myc- and L-Myc-dependent proliferation. It is effective in vivo, reducing the growth of breast cancer MDA-MB-231 xenografts in mice.
