Publications by authors named "Masahiro Osawa"

Vandetanib (ZactimaTM) is a novel, orally available inhibitor of both vascular endothelial growth factor receptor-2 (VEGFR-2) and epidermal growth factor receptor (EGFR) tyrosine kinase. In the present study, a line of transgenic mice with a mouse Egfr gene mutation (delE748-A752) corresponding to a human EGFR mutation (delE746-A750) was established. The transgenic mice developed atypical adenomatous hyperplasia to adenocarcinoma of the lung at around 5 weeks of age and died of lung tumors at approximately 17 weeks of age.

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Background: Drug-induced interstitial lung disease (ILD) is one of the most serious adverse reactions associated with the molecularly targeted drugs. Panitumumab has been approved for advanced or recurrent colorectal cancer. Although there were no adverse reaction reports of ILD in panitumumab monotherapy, 4 cases in combination chemotherapy were reported prior to its approval in Japan in 2010.

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Tumors are presumed to contain a small population of cancer stem cells (CSCs) that initiate tumor growth and promote tumor spreading. Multidrug resistance in CSCs is thought to allow the tumor to evade conventional therapy. This study focused on expression of CD133 and CD87 because CD133 is a putative marker of CSCs in some cancers including lung, and CD87 is associated with a stem-cell-like property in small-cell lung cancer (SCLC).

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Background: The survival advantage achieved by existing anti-cancer agents as second-line therapy for relapsed non-small cell lung cancer (NSCLC) is modest and further improvement of treatment outcome is desired. Combination chemotherapy with irinotecan and amrubicin for advanced NSCLC has not been fully evaluated.

Methods: The primary endpoint of this phase II clinical trial was objective response.

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Twenty-five percent of all lung cancer cases are not attributable to smoking. Epidermal growth factor receptor (EGFR) mutations, which are involved in approximately 50% of nonsmoker lung cancer, are positively correlated with responsiveness to gefitinib, and inversely correlated with smoking history. Activating EGFR mutations play a critical role in the carcinogenesis of nonsmoking-related lung cancer.

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Vandetanib is a novel multitarget tyrosine kinase inhibitor (TKI) that inhibits vascular endothelial growth factor receptor-2 (VEGFR-2), with additional inhibition of epidermal growth factor receptor (EGFR) and rearranged during transfection receptor signaling, which has shown promising results in clinical trials for advanced non-small cell lung cancer. However, the mechanisms of acquired resistance to vandetanib remain unclear. Therefore, we established in vitro vandetanib-resistant PC-9/VanR cells from PC-9, a vandetanib-sensitive lung adenocarcinoma cell line, by chronic exposure to this agent.

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To investigate the role of an activating epidermal growth factor receptor (EGFR) mutation in lung cancer, we generated transgenic mice expressing the delE748-A752 mutant version of mouse EGFR driven by the SP-C promoter, which is equivalent to the delE746-A750 mutation found in lung cancer patients. Strikingly, the mice invariably developed multifocal lung adenocarcinomas of varying sizes at between 5 and 6 weeks of age, and they died from tumor progression approximately 2 months later if left untreated. Daily oral administration of the EGFR tyrosine kinase inhibitor (TKI) gefitinib (5 mg/kg/day) reduced the total and phosphorylation levels of EGFR to those in wild-type mouse lung tissue; in addition, it abrogated tumor growth within 1 week and prolonged survival to >30 weeks.

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A 67-year-old man with lung cancer developed an isolated metastasis to the thyroid gland. The patient had undergone a right upper lobectomy, followed by chemotherapy consisting of cisplatin and etoposide based on post-surgical diagnosis of small cell lung cancer. Four years later, he had an isolated metastasis to the thyroid gland.

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Irinotecan is one of the effective anticancer agents for small-cell lung cancer (SCLC) and 7-ethyl-10-hydroxy-campthothecin (SN-38) is an active metabolite of irinotecan. Gefitinib and imatinib are tyrosine kinase inhibitors which have clinical activities in several malignancies and they are also potent inhibitors of breast cancer resistance protein (BCRP) transporter, which confers the resistance of topoisomerase I inhibitors including SN-38 and topotecan. The cytotoxicity of SN-38, gefitinib and imatinib for the SN-38-resistant cells (SBC-3/SN-38) from human SCLC cells, SBC-3, was evaluated using AlamarBlue assay.

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