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Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor (epidermal + growth_factor_receptor_tyrosine_kinase_inhibitor)
Selected AbstractsChemInform Abstract: Studies Leading to the Identification of ZD1839 (Iressa): An Orally Active, Selective Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Targeted to the Treatment of Cancer.CHEMINFORM, Issue 46 2001Keith H. Gibson Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] High incidence of disease recurrence in the brain and leptomeninges in patients with nonsmall cell lung carcinoma after response to gefitinibCANCER, Issue 11 2005Antonio M. P. Omuro M.D. Abstract BACKGROUND Gefitinib is an epidermal growth factor receptor tyrosine kinase inhibitor that induces an early and dramatic response in 10% of patients with advanced nonsmall cell lung carcinoma (NSCLC). Long- term outcome and patterns of disease recurrence after response have not been described. METHODS The authors evaluated 139 patients with NSCLC treated with gefitinib at Memorial Sloan-Kettering Cancer Center (New York, NY) between 1998 and 2002. They focused on patterns of disease recurrence, risk of brain metastases (BM) and leptomeningeal metastasis (LM), and long-term outcome after initial response to gefitinib. RESULTS Of the 139 patients treated with gefitinib, 21 (15%) achieved a partial response. The median age of the responders was 64 years (range, 38,87 years), the median Karnofsky performance score was 80 (range, 60,90), and 4 of the patients were men. All responders had adenocarcinoma. The central nervous system (CNS) was the initial site of disease recurrence in 7 (33%) patients (BM in 5 and LM in 2). In 9 (43%) patients, the initial site of disease recurrence was the lung and in 1 it was the liver and bone. Four (57%) of the patients with disease recurrence in the CNS had lung disease under control. BM also developed in 2 patients who had initial disease recurrence in the lungs. The actuarial 5-year incidence of CNS metastases was 60%. The median overall survival periods were 15 months and 23 months for patients with and without CNS metastases, respectively (P = 0.24). CONCLUSIONS The CNS was a frequent site of disease recurrence in patients with NSCLC after an initial response to gefitinib, regardless of disease control in the lungs. Patients should be carefully monitored for neurologic symptoms. Intrinsic resistance of metastatic clones, incomplete CNS penetrance of the drug, and longer survival are possible explanations for this high incidence. Cancer 2005. © 2005 American Cancer Society. [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] The effect of ZD1839 (IressaTM), an epidermal growth factor receptor tyrosine kinase inhibitor, in combination with cisplatin, on apoptosis in SCC-15 cellsCELL PROLIFERATION, Issue 2 2005A. Al-Hazzaa High expression of the epidermal growth factor receptor has been implicated in the development of squamous cell carcinomas of head and neck. ZD1839 (,Iressa') is an orally active, selective epidermal growth factor receptor tyrosine kinase inhibitor that blocks signal transduction pathways implicated in proliferation and survival of cancer cells, and other host-dependent processes promoting cancer growth. Here, growth arrest was observed with 3.64 µm ZD1839. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (sMTT) viability assay revealed a significant decrease (P < 0.001) in the percentage of surviving cells upon treatment with ZD1839 and cisplatin compared with cisplatin or ZD1839 on their own. Combined therapy of 3.64 µm ZD1839 for 24 h, prior to administration of 100 µm cisplatin, significantly (P < 0.001) and additively increased the cytotoxicity effect of cisplatin. p53-independent apoptosis was seen with cisplatin treatment, a novel finding. These data support the use of ZD1839 in anti-cancer therapy, and particularly in combination therapy. Cisplatin may induce p53-independent apoptosis. Over-expression of Bcl-2 in head and neck squamous cell carcinoma tumour cell lines is unlikely to be a general mechanism to protect these cells from apoptosis. [source] GM3 synthase gene is a novel biomarker for histological classification and drug sensitivity against epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancerCANCER SCIENCE, Issue 10 2007Mariko Noguchi Expression of gangliosides and alterations in their composition have been observed during cell proliferation and differentiation and in certain cell cycle phases, brain development and cancer malignancy. To investigate the characteristics of GM3 synthase, SAT-I mRNA and ganglioside GM3 expression levels in lung cancer, we examined the expression levels of SAT-I mRNA as well as GM3 in 40 tumor tissues surgically removed from non-small cell lung cancer patients. Adenocarcinoma tissues expressed SAT-I mRNA levels that were significantly higher than those of squamous and other carcinomas (P < 0.0001). Moreover, the SAT-I mRNA levels were high in the bronchioalveolar carcinoma subtype and low in the solid and mucin subtypes of adenocarcinomas (P = 0.049, 0.049 and 0.013, respectively). To clarify the relationship between SAT-I mRNA and epidermal growth factor receptor (EGFR)-tyrosine kinase (TK) inhibitor sensitivity, we carried out drug sensitivity tests for the EGFR-TK inhibitors gefitinib and AG1478 using eight adenocarcinoma cell lines expressing no EGFR mutations. The IC50 values for gefitinib and AG1478 decreased dramatically with increasing SAT-I mRNA levels (R2 = 0.81 and 0.59, respectively), representing a wide range of drug sensitivities among adenocarcinoma cell lines. To explore a possible mechanism of how GM3 could enhance the sensitivity to EGFR-TK inhibitors, the SAT-I gene was introduced stably into a GM3-negative clone of murine 3LL lung cancer cells to produce GM3-reconstituted clones. We found an increase in EGFR protein levels and gefitinib sensitivity in GM3-reconstituted cells, suggesting the involvement of GM3 in the turnover of EGFR protein. Therefore, it is highly expected that, by measuring the expression levels of SAT-I mRNA in lung biopsy samples from non-small cell lung cancer patients, enhanced pathological identification and individualized chemotherapeutic strategies can be established for the appropriate use of EGFR-TK inhibitors. (Cancer Sci 2007; 98: 1625,1632) [source] | ||||||||||