The combi-targeting concept: a novel 3,3-disubstituted nitrosourea with EGFR tyrosine kinase inhibitory properties

摘要: PURPOSE To study the dual mechanism of action FD137, a 3,3-disubstituted nitrosourea designed to block signaling mediated by epidermal growth factor receptor (EGFR) on its own and be hydrolyzed an inhibitor EGFR plus DNA-damaging species. MATERIALS AND METHODS HPLC was used determine half-life (t(1/2)) FD137 characterize derived metabolite FD110. The mechanisms DNA damaging tyrosine kinase (TK) targeting were ascertained comet assay for damage inmunodetection phosphotyrosine in ELISA whole-cell EGFR-mediated signaling. antiproliferative effects different drugs their combinations determined sulforhodamine B (SRB) assay. RESULTS In contrast BCNU, significantly blocked EGF-induced autophosphorylation (IC(50) 4 micro M) human solid tumor cell line A431. induced could only observed after 24 h exposure, but level remained 3.6-fold lower than that BCNU. This difference rationalized 160-fold greater stability when compared with BCNU serum-containing medium. Further, degradation accompanied slow release FD110, extremely potent TK [IC(50) (EGFR autophosphorylation) <0.3 M]. complex properties translated into 55-fold activity against EGFR-overexpressing A431 cells coexpresses O(6)-alkylguanine transferase (AGT). Depletion AGT these use O(6)-benzylguanine (O(6)-BG) enhanced sensitivity 8-fold, 3-fold FD137. CONCLUSIONS results overall suggest superior may associated ability behave as combination many species action. However, enhancement potency O(6)-BG suggests effect at least partially mitigated perhaps it largely dominated signal transduction inhibitory component.