The Effects of the Novel, Reversible Epidermal Growth Factor Receptor/ErbB-2 Tyrosine Kinase Inhibitor, GW2016, on the Growth of Human Normal and Tumor-derived Cell Lines in Vitro and in Vivo

• Published in: Molecular cancer therapeutics Vol. 1; no. 2; pp. 85 - 94
• Main Authors: Rusnak, D W, Lackey, K, Affleck, K, Wood, E R, Alligood, K J, Rhodes, N, Keith, B R, Murray, D M, Knight, W B, Mullin, R J, Gilmer, T M
• Format: Journal Article
• Language: English
• Published: United States American Association for Cancer Research 01-12-2001
• Subjects: Animals; Antineoplastic Agents - pharmacology; Apoptosis; Blotting, Western; Cell Cycle - drug effects; Cell Division - drug effects; Enzyme Inhibitors - pharmacology; Epidermal Growth Factor - pharmacology; Female; Fibroblasts - drug effects; Furans - pharmacology; Humans; Infant, Newborn; Mice; Mice, Nude; Mice, SCID; Neoplasms, Experimental - drug therapy; Neoplasms, Experimental - metabolism; Neoplasms, Experimental - pathology; Phosphorylation; Precipitin Tests; Quinazolines - pharmacology; Receptor, Epidermal Growth Factor - antagonists & inhibitors; Receptor, Epidermal Growth Factor - metabolism; Receptor, ErbB-2 - antagonists & inhibitors; Receptor, ErbB-2 - metabolism; Signal Transduction - drug effects; Skin - cytology; Tumor Cells, Cultured - drug effects; Tumor Cells, Cultured - metabolism; Xenograft Model Antitumor Assays
• ISSN: 1535-7163; 1538-8514

The epidermal growth factor receptor (EGFR) and ErbB-2 transmembrane tyrosine kinases are currently being targeted by various
mechanisms in the treatment of cancer. GW2016 is a potent inhibitor of the ErbB-2 and EGFR tyrosine kinase domains with IC 50 values against purified EGFR and ErbB-2 of 10.2 and 9.8 n m , respectively. This report describes the efficacy in cell growth assays of GW2016 on human tumor cell lines overexpressing
either EGFR or ErbB-2: HN5 (head and neck), A-431 (vulva), BT474 (breast), CaLu-3 (lung), and N87 (gastric). Normal human
foreskin fibroblasts, nontumorigenic epithelial cells (HB4a), and nonoverexpressing tumor cells (MCF-7 and T47D) were tested
as negative controls. After 3 days of compound exposure, average IC 50 values for growth inhibition in the EGFR- and ErbB-2-overexpressing tumor cell lines were <0.16 μ m . The average selectivity for the tumor cells versus the human foreskin fibroblast cell line was 100-fold. Inhibition of EGFR and ErbB-2 receptor autophosphorylation and phosphorylation
of the downstream modulator, AKT, was verified by Western blot analysis in the BT474 and HN5 cell lines. As a measure of cytotoxicity
versus growth arrest, the HN5 and BT474 cells were assessed in an outgrowth assay after a transient exposure to GW2016. The cells
were treated for 3 days in five concentrations of GW2016, and cell growth was monitored for an additional 12 days after removal
of the compound. In each of these tumor cell lines, concentrations of GW2016 were reached where outgrowth did not occur. Furthermore,
growth arrest and cell death were observed in parallel experiments, as determined by bromodeoxyuridine incorporation and propidium
iodide staining. GW2016 treatment inhibited tumor xenograft growth of the HN5 and BT474 cells in a dose-responsive manner
at 30 and 100 mg/kg orally, twice daily, with complete inhibition of tumor growth at the higher dose. Together, these results
indicate that GW2016 achieves excellent potency on tumor cells with selectivity for tumor versus normal cells and suggest that GW2016 has value as a therapy for patients with tumors overexpressing either EGFR or ErbB-2.