In vitro activity: AEE788 also inhibits KDR, c-abl, c-Src, and Flt-1 with IC50 of 50-80 nM. AEE788 is not sensitive to ErbB-4, PDGFR-β, Flt-3, Flt-4, RET, and c-Kit and has no inhibitory to Ins-R, IGF-1R, PKC-α, and PKA. AEE788 potently inhibits EGFR phosphorylation in A431 cells with IC50 of 11 nM. AEE788 also inhibits the phosphorylation of KDR in CHO cells and erbB2 in BT-474 cells, without any effects on PDGF-induced phosphorylation in A31 cells. AEE788 inhibits the proliferation of NCI-H596, MK, BT-474 and SK-BR-3 cells with IC50 of 78, 56, 49 and 381 nM, respectively. Otherwise, AEE788 has the additional property of inhibiting cellular proliferation driven by EGFR mutant including 32D/EGFR and 32D/EGFRvIII. AEE788 furtheralso inhibits both EGF- and VEGF-driven HUVEC proliferation with IC50 of 43 and 155 nM, respectively. AEE788 inhibits the phosphorylation of EGFR, VEGFR2, Akt, and MAPK in human cutaneous SCC cell lines (Colo16, HaCaT, SRB1, and SRB12 cells), which leads to growth inhibition and induction of apoptosis. AEE788 inhibits the phosphorylation of EGFR and Akt in HT29 cells at 0.2 to 1.0 μM. AEE788 inhibits cell proliferation and prevents EGF- and neuregulin-induced HER1, HER2, and HER3 activation in medulloblastoma cell lines. AEE788 shows growth-suppressive activities in chemosensitive and chemoresistant medulloblastoma cells.

Kinase Assay: The in vitro kinase assays are performed in 96-well plates (30 μL) at ambient temperature for 15–45 min using the recombinant glutathione S-transferase-fused kinase domains (4-100 ng, depending on specific activity). [γ33P]ATP is used as phosphate donor and polyGluTyr-(4:1) peptide as acceptor. With the exception of protein kinase C-α, cyclin-dependent kinase 1/cycB and protein kinase A are protamine sulfate (200 μg/mL), histone H1 (100 μg/mL), and the heptapeptide Leu-Arg-Arg-Ala-Ser-Leu-Gly (known as Kemptide Bachem) respectively and are used as peptide substrates. Assays are optimized for each kinase using the following ATP concentrations: 1.0 μM (c-Kit, c-Met, c-Fms, c-Raf-1, and RET), 2.0 μM (EGFR, erbB2, ErbB3, and ErbB4), 5.0 μM (c-abl), 8.0 μM (Flt-1, Flt-3, Flt-4, Flk, KDR, FGFR-1, and Tek), 10.0 μM (PDGFR-β, protein kinase C-α, and cyclin-dependent kinase 1), and 20.0 μM (c-Src and protein kinase A). The reaction is terminated by the addition of 20 μL 125 mM EDTA. Thirty μL (c-abl, c-Src, insulin-like growth factor-1R, RET-Men2A, and RET-Men2B) or 40 μL (all other kinases) of the reaction mixture is transferred onto Immobilon-polyvinylidene difluoride membrane, presoaked with 0.5% H3PO4 and mounted on a vacuum manifold. Vacuum is then applied and each well rinsed with 200 μL 0.5% H3PO4. Membranes are removed and washed four times with 1.0% H3PO4 and once with ethanol. Dried membranes are counted after mounting in a Packard TopCount 96-well frame and with the addition of 10 μL/well of Microscint. IC50 values (±SE) are calculated by linear regression analysis of the percentage inhibition and are averages of at least three determinations.

Cell Assay: Methylene Blue Cell Proliferation Assay.Cells are seeded at 1.5 × 103 cells/well into 96-well microtiter plates and incubated overnight at 37 °C, 5% v/v CO2 and 80% relative humidity. AEE788 dilutions are added on day 1, with the highest concentration being 10 μM. After incubation of the cell plates for an additional 4 (T24) or 6 (BT-474, SK-BR-3, and NCI-H596) days, cells are fixed with 3.3% v/v glutaraldehyde, washed with water, and stained with 0.05% w/v methylene blue. After washing, the dye is eluted with 3% HCl and the absorbance measured at 665 nm with a SpectraMax 340 spectrophotometer. IC50 values are determined by mathematical curve-fitting and are defined as the drug concentration leading to 50% inhibition of net cell mass increase compared with untreated control cultures.

Cancer Res. 2004 Jul 15;64(14):4931-41; Cancer Res. 2005 May 1;65(9):3716-25; Clin Cancer Res. 2007 Feb 15;13(4):1140-8.