Compound D7 does not block activation of the MEK/ERK pathway in EGF-stimulated HeLa cells. HeLa cells incubated with DMSO, compound D7 or U0126 were activated with EGF and the levels of MAP kinase phosphorylation were determined by Western blot using anti-phospho ERK1/2 antibody. Compound D7 at 10 and 100 μM, and DMSO at 0.1 and 1%, did not prevent phosphorylation of MAP kinase following EGF stimulation of HeLa cells. U0126 at 10 and 25 μM completely prevented phosphorylation of MAP kinase. Blots were probed with antibody to phosphorylated MAPK (upper panel), and with antibody to total MAPK (lower panel).