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EGFR Tyrosine Kinase Inhibitors (egfr tyrosine + kinase_inhibitor)
Selected AbstractsSynthesis and Biological Evaluation of Bis(methoxymethyl)-7,8-dihydro-[1,4]dioxino[2,3-g]quinazolines as EGFR Tyrosine Kinase Inhibitors.CHEMINFORM, Issue 7 2006Yong Sup Lee Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF. [source] Association of epidermal growth factor receptor mutations in lung cancer with chemosensitivity to gefitinib in isolated cancer cells from Japanese patientsEUROPEAN JOURNAL OF CANCER CARE, Issue 3 2007K. NAKATANI md, assistant professor Somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene are reported to be associated with clinical responsiveness of lung cancer to gefitinib, an EGFR tyrosine kinase inhibitor. To elucidate the association between somatic mutations and the pharmacological actions of gefitinib, the chemosensitivity of isolated cancer cells from the lungs of Japanese patients to gefitinib was examined by the collagen gel-droplet embedded culture drug sensitivity test in vitro. In 30 specimens isolated from non-small-cell lung cancer patients, mutations were observed in eight tumour specimens (27%) and chemosensitivity to gefitinib was observed in seven specimens (23%). However, somatic mutations were not predominantly associated with chemosensitivity to gefitinib in vitro. Both mutation and chemosensitivity frequencies in this study were higher than those reported in studies from the United States, indicating a possible ethnic difference. Moreover, both frequencies were much higher in females than in males. Since a gender difference in chemosensitivity to gefitinib was observed in isolated cancer cells in vitro, this suggests that gefitinib works in part through the suppression of EGFR signalling, but that other factors, including sex-related factors, may participate in gefitinib action. [source] Anticancer effects of ZD6474, a VEGF receptor tyrosine kinase inhibitor, in gefitinib ("Iressa")-sensitive and resistant xenograft modelsCANCER SCIENCE, Issue 12 2004Fumiko Taguchi ZD6474 is a novel, orally available inhibitor of vascular endothelial growth factor (VEGF) receptor-2 (KDR) tyrosine kinase, with additional activity against epidermal growth factor receptor (EGFR) tyrosine kinase. ZD6474 has been shown to inhibit angiogenesis and tumor growth in a range of tumor models. Gefitinib ("Iressa") is an selective EGFR tyrosine kinase inhibitor (TKI) that blocks signal transduction pathways. We examined the antitumor activity of ZD6474 in the gefitinib-sensitive lung adenocarcinoma cell line, PC-9, and a gefitinib-resistant variant (PC-9/ZD). PC-9/ZD cells showed cross-resistance to ZD6474 in an in vitro dye formation assay. In addition, ZD6474 showed dose-dependent inhibition of EGFR phosphorylation in PC-9 cells, but inhibition was only partial in PC-9/ZD cells. ZD6474-mediated inhibition of tyrosine residue phosphorylation (Tyr992 and Tyr1045) on EGFR was greater in PC-9 cells than in PC-9/ZD cells. These findings suggest that the inhibition of EGFR phosphorylation by ZD6474 can contribute a significant, direct growth-inhibitory effect in tumor cell lines dependent on EGFR signaling for growth and/or survival. The effect of ZD6474 (12.5,50 mg/kg/day p.o. for 21 days) on the growth of PC-9 and PC-9/ZD tumor xenografts in athymic mice was also investigated. The greatest effect was seen in gefitinib-sensitive PC-9 tumors, where ZD6474 treatment (>12.5 mg/kg/day) resulted in tumor regression. Dose-dependent growth inhibition, but not tumor regression, was seen in ZD6474-treated PC-9/ZD tumors. These studies demonstrate that the additional EGFR TKI activity may contribute significantly to the anti-tumor efficacy of ZD6474, in particular in those tumors that are dependent on continued EGFR-signaling for proliferation or survival. In addition, these results provide a preclinical rationale for further investigation of ZD6474 as a potential treatment option for both EGFR-TKI-sensitive and EGFR-TKI-resistant tumors. [source] EGF receptor in relation to tumor development: molecular basis of responsiveness of cancer cells to EGFR-targeting tyrosine kinase inhibitorsFEBS JOURNAL, Issue 2 2010Kenji Takeuchi The function of the epidermal growth factor receptor (EGFR) is dysregulated in various types of malignancy as a result of gene amplification, mutations, or abnormally increased ligand production. Therefore, the tyrosine kinase activity of the EGFR is a promising therapeutic target. EGFR tyrosine kinase inhibitors, such as gefitinib (Iressa), show evident anticancer effects in patients with non-small cell lung cancer. The induction of apoptosis has been considered to be the major mechanism for these gefitinib-mediated anticancer effects. Lung cancer cells harboring mutant EGFRs become dependent on them for their survival and, consequently, undergo apoptosis following the inhibition of EGFR tyrosine kinase by gefitinib. Gefitinib has been shown to inhibit cell survival and growth signaling pathways such as the extracellular signal-regulated kinase 1/2 pathway and the Akt pathway, as a consequence of the inactivation of EGFR. However, the precise downstream signaling molecules of extracellular signal-regulated kinase 1/2 and Akt have not yet been elucidated. In this minireview we have highlighted the effect of tyrosine kinase inhibitors on members of the Bcl-2 family of proteins, which are downstream signaling molecules and serve as the determinants that control apoptosis. We also discuss tyrosine kinase inhibitor-induced apoptosis via c-Jun NH2 -terminal kinase and p38 mitogen-activated protein kinase. [source] Epidermal growth factor receptor lacking C-terminal autophosphorylation sites retains signal transduction and high sensitivity to epidermal growth factor receptor tyrosine kinase inhibitorCANCER SCIENCE, Issue 3 2009Mari Maegawa Constitutively active mutations of epidermal growth factor receptor (EGFR) (delE746_A750) activate downstream signals, such as ERK and Akt, through the phosphorylation of tyrosine residues in the C-terminal region of EGFR. These pathways are thought to be important for cellular sensitivity to EGFR tyrosine kinase inhibitors (TKI). To examine the correlation between phosphorylation of the tyrosine residues in the C-terminal region of EGFR and cellular sensitivity to EGFR TKI, we used wild-type (wt) EGFR, as well as the following constructs: delE746_A750 EGFR; delE746_A750 EGFR with substitution of seven tyrosine residues to phenylalanine in the C-terminal region; and delE746_A750 EGFR with a C-terminal truncation at amino acid 980. These constructs were transfected stably into HEK293 cells and designated HEK293/Wt, HEK293/D, HEK293/D7F, and HEK293/D-Tr, respectively. The HEK293/D cells were found to be 100-fold more sensitive to EGFR TKI (AG1478) than HEK293/Wt. Surprisingly, the HEK293/D7F and HEK293/D-Tr cells, transfected with EGFR lacking the C-terminal autophosphorylation sites, retained high sensitivity to EGFR TKI. In these three high-sensitivity cells, the ERK pathway was activated without ligand stimulation, which was inhibited by EGFR TKI. In addition, although EGFR in the HEK293/D7F and HEK293/D-Tr cells lacked significant tyrosine residues for EGFR signal transduction, phosphorylation of Src homology and collagen homology (Shc) was spontaneously activated in these cells. Our results indicate that tyrosine residues in the C-terminal region of EGFR are not required for cellular sensitivity to EGFR TKI, and that an as-yet-unknown signaling pathway of EGFR may exist that is independent of the C-terminal region of EGFR. (Cancer Sci 2009; 100: 552,557) [source] Mutations of the epidermal growth factor receptor gene and related genes as determinants of epidermal growth factor receptor tyrosine kinase inhibitors sensitivity in lung cancerCANCER SCIENCE, Issue 12 2007Tetsuya Mitsudomi Recent discovery of mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene in lung adenocarcinoma greatly stimulated biomarker research on predictive factors for EGFR tyrosine kinase inhibitors (TKI), such as gefitinib and erlotinib. Although patients with activating mutations of the EGFR generally respond to EGFR TKIs very well, it is natural to assume that there is no sole determinant, considering great complexity and redundancy of the EGFR pathway. Subsequently, roles of different types of EGFR mutations or mutations of genes that are members of the EGFR pathway such as KRAS and HER2 have been evaluated. In this review, we summarize the recent findings about how mutations of the EGFR and related genes affect sensitivity to EFGR-TKIs. We also discuss molecular mechanisms of acquired resistance to EGFR-TKIs that is almost inevitable in EGFR-TKI therapy. The door for genotype-based treatment of lung cancer is beginning to open, and through these efforts, it will be possible to slow the progression of lung cancer and eventually, to decrease mortality from lung cancer. (Cancer Sci 2007; 98: 1817,1824) [source] | |||||||||||||