Isamu Okamoto

Kyushu University, Hukuoka, Fukuoka, Japan

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Publications (233)1346.82 Total impact

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    ABSTRACT: Background: Amphiregulin, a ligand of the epidermal growth factor receptor (EGFR), is associated with the efficacy of cetuximab, an antibody against EGFR, as treatment for colorectal cancer (CRC). In contrast, the HER3 ligand heregulin correlates with cetuximab resistance. In this study, we evaluated how the combined levels of circulating amphiregulin and heregulin affect clinical outcomes in patients who receive cetuximab as therapy against advanced CRC. Methods: Plasma levels of amphiregulin and heregulin were measured by enzyme-linked immunosorbent assay in 50 patients with CRC in a training cohort, and in 10 patients in a validation cohort. The combined expression was then assessed with clinical outcome after receiver operating characteristics analysis. Results: Overall response rate was 26%, and median progression-free survival was 110 days in the training cohort. Patients with high amphiregulin and low heregulin had significantly higher objective response rate at 58% and significantly longer progression-free survival of 216 days. This result was confirmed in the validation cohort. Conclusion: A subgroup of CRC patients with high amphiregulin and low heregulin respond to cetuximab therapy better than other patients.
    PLoS ONE 11/2015; 10(11):e0143132. DOI:10.1371/journal.pone.0143132 · 3.23 Impact Factor
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    ABSTRACT: Purpose: This open-label, phase I, dose-escalation part of a phase I/II study evaluated the safety, pharmacokinetics, and preliminary efficacy of nintedanib, a triple angiokinase inhibitor, combined with pemetrexed in Japanese patients with advanced non-small cell lung cancer (NSCLC) after first-line chemotherapy. Methods: A fixed dose of pemetrexed (500 mg/m(2) iv) was administered on Day 1 of each 21-day cycle followed by oral nintedanib twice daily (bid) on days 2-21, starting at 100 mg bid and escalating to 200 mg bid in 50-mg intervals, using a standard 3 + 3 design. After ≥4 cycles of combination therapy, patients could continue nintedanib monotherapy until disease progression or undue adverse events (AEs). Primary endpoints were maximum tolerated dose (MTD), defined as the highest dose at which the incidence of dose-limiting toxicities (DLTs) was <33.3 % during the first treatment course, and AEs (CTCAE v3.0). DLTs were primarily defined as grade ≥3 non-hematologic or grade 4 hematologic AEs. Results: Eighteen patients were included in the analysis. DLTs were experienced by 2/9 patients receiving 200 mg bid, 1/6 receiving 150 mg bid, and 0/3 receiving the lowest dose. The MTD of nintedanib plus pemetrexed was 200 mg bid. The most common drug-related AEs were elevated liver enzymes and gastrointestinal AEs. Two patients achieved partial response, and 10 had stable disease. Conclusions: Nintedanib plus pemetrexed had a manageable safety profile and showed promising signs of efficacy in previously treated Japanese patients with advanced NSCLC. As in Caucasian patients, the MTD of nintedanib was 200 mg bid. Clinical trial information NCT00979576.
    Cancer Chemotherapy and Pharmacology 11/2015; 76(6). DOI:10.1007/s00280-015-2896-3 · 2.77 Impact Factor
  • Isamu Okamoto · Masayuki Takeda · Kazuhiko Nakagawa ·

    Therapeutics and Clinical Risk Management 11/2015; DOI:10.2147/TCRM.S76646 · 1.47 Impact Factor
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    ABSTRACT: Afatinib is a second generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) characterized as an irreversible pan-human EGFR (HER) family inhibitor. Afatinib remains effective for a subpopulation of patients with non-small cell lung cancer (NSCLC) with acquired resistance to first generation EGFF-TKIs such as erlotinib. Heregulin activates HER3 in an autocrine fashion and causes erlotinib resistance in NSCLC. Here we examine whether afatinib is effective against heregulin-overexpressing NSCLCs harboring EGFR activating mutations. Afatinib but not erlotinib decreased EGFR mutant NSCLC PC9HRG cell proliferation in vitro and in mouse xenografts. Afatinib inhibited phosphorylation of the cell signaling pathway proteins HER3, EGFR, HER2, and HER4, likely by prevention of trans-phosphorylation as HER3 kinase activity is inadequate for auto-phosphorylation. Afatinib, unlike erlotinib, inhibited AKT activation, resulting in elevated apoptosis in PC9HRG cells. Clinically, a subpopulation of 33 patients with EGFR mutations and NSCLC who had received first generation EGFR-TKIs exhibited elevated plasma heregulin levels compared to healthy volunteers; one of these achieved a response with afatinib therapy despite having previously developed erlotinib resistance. Afatinib can overcome heregulin-mediated resistance to erlotinib in EGFR mutant NSCLC. Further studies are necessary to determine whether heregulin can predict afatinib efficacy after development offirst generation EGFR-TKI resistance.
    Oncotarget 09/2015; DOI:10.18632/oncotarget.5286 · 6.36 Impact Factor
  • Shinya Sakata · Eiji Iwama · Isamu Okamoto ·

    Gan to kagaku ryoho. Cancer & chemotherapy 09/2015; 42(8):935-9.
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    ABSTRACT: Alectinib, the second generation anaplastic lymphoma kinase (ALK) inhibitor, has significant potency in patients with ALK rearrangement positive non-small cell lung cancer (NSCLC), and its toxicity is generally well tolerable. We report a patient who developed severe acute interstitial lung disease after alectinib treatment. An 86-year-old woman with stage IV lung adenocarcinoma positive for rearrangement of ALK gene was treated with alectinib. On the 215th day after initiation of alectinib administration, she was admitted to our hospital with the symptom of progressive dyspnea. Computed tomography (CT) revealed diffuse ground glass opacities and consolidations in both lungs, and analysis of bronchoalveolar lavage fluid revealed pronounced lymphocytosis. There was no evidence of infection or other specific causes of her condition, and she was therefore diagnosed with interstitial lung disease induced by alectinib. Her CT findings and respiratory condition improved after steroid pulse therapy. As far as we are aware, this is the first reported case of alectinib-induced severe interstitial lung disease (ILD). We should be aware of the possibility of such a severe adverse event and should therefore carefully monitor patients treated with this drug.
    Investigational New Drugs 09/2015; 33(5). DOI:10.1007/s10637-015-0284-9 · 2.92 Impact Factor
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    ABSTRACT: As the development of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has become an issue of concern, identification of the mechanisms responsible has become an urgent priority. However, for research purposes, it is not easy to obtain tumor samples from patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC) that has relapsed after treatment with EGFR-TKIs. Here, using digital PCR assay as an alternative and noninvasive method, we examined plasma and tumor samples from patients with relapsed NSCLC to establish the inter-relationships existing among T790M mutation, activating EGFR mutations, HER2 amplification, and MET amplification. Paired samples of tumor and blood were obtained from a total of 18 patients with NSCLC after they had developed resistance to EGFR-TKI treatment, and the mechanisms of resistance were analyzed by digital PCR. Digital PCR analysis of T790M mutation in plasma had a sensitivity of 81.8% and specificity of 85.7%, the overall concordance between plasma and tissue samples being 83.3%. MET gene copy number gain in tumor DNA was observed by digital PCR in three patients, of whom one exhibited positivity for MET amplification by FISH, whereas no patient demonstrated MET and HER2 copy number gain in plasma DNA. Digital PCR analysis of plasma is feasible and accurate for detection of T790M mutation in NSCLC that becomes resistant to treatment with EGFR-TKIs.
    Oncotarget 08/2015; DOI:10.18632/oncotarget.5068 · 6.36 Impact Factor
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    ABSTRACT: In LUX-Lung 3, afatinib significantly improved progression-free survival (PFS) versus cisplatin/pemetrexed in EGFR mutation-positive lung adenocarcinoma patients and overall survival (OS) in Del19 patients. Preplanned analyses in Japanese patients from LUX-Lung 3 were performed. Patients were randomized 2:1 to afatinib or cisplatin/pemetrexed, stratified by mutation type (Del19/L858R/Other). Primary endpoint was PFS (independent review). Secondary endpoints included OS, objective response, and safety. Median PFS (data cut-off: February 2012) for afatinib versus cisplatin/pemetrexed was 13.8 versus 6.9 months (HR, 0.38; 95% CI, 0.20–0.70; P=0.0014) in all Japanese patients (N=83), with more pronounced improvements in those with common mutations (Del19/L858R; HR, 0.28; 95% CI, 0.15–0.52; P<0.0001) and Del19 mutations (HR, 0.16; 95% CI, 0.06–0.39; P<0.0001). PFS was also improved in L858R patients (HR, 0.50; 95% CI, 0.20–1.25; P=0.1309). Median OS (data cut-off: November 2013) with afatinib versus cisplatin/pemetrexed was 46.9 versus 35.8 months (HR, 0.75; 95% CI, 0.40–1.43; P=0.3791) in all Japanese patients, with greater benefit in patients with common mutations (HR, 0.57; 95% CI, 0.29–1.12; P=0.0966) and Del19 mutations (HR, 0.34; 95% CI, 0.13–0.87; P=0.0181); OS was not significantly different in L858R patients (HR, 1.13; 95% CI, 0.40–3.21; P=0.8212). Following study treatment discontinuation, most patients (93.5%) received subsequent anticancer therapy. The most common treatment-related adverse events were diarrhea, rash/acne, nail effects and stomatitis with afatinib and nausea, decreased appetite, neutropenia, and leukopenia with cisplatin/pemetrexed. Afatinib significantly improved PFS versus cisplatin/pemetrexed in Japanese EGFR mutation-positive lung adenocarcinoma patients and OS in Del19 but not L858R patients. (www clinicaltrials. gov; NCT00949650).This article is protected by copyright. All rights reserved.
    Cancer Science 06/2015; 106(9). DOI:10.1111/cas.12723 · 3.52 Impact Factor
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    ABSTRACT: This analysis compared the quality-adjusted survival and clinical outcomes of albumin-bound paclitaxel+carboplatin (nab-PC) vs solvent-based paclitaxel+carboplatin (sb-PC) as first-line therapy in advanced non-small-cell lung cancer (NSCLC) in older patients. Using age-based subgroup data from a randomised Phase-3 clinical trial, nab-PC and sb-PC were compared with respect to overall response rate (ORR), overall survival (OS), progression-free survival (PFS), quality of life (QoL), safety/toxicity, and quality-adjusted time without symptoms or toxicity (Q-TWiST) with ages ⩾60 and ⩾70 years as cut points. Among patients aged ⩾60 years (N=546), nab-PC (N=265) significantly increased ORR and prolonged OS, despite a non-significant improvement in PFS, vs sb-PC (N=281). Nab-PC improved QoL and was associated with less neuropathy, arthralgia, and myalgia but resulted in more anaemia and thrombocytopenia. Nab-PC yielded significant Q-TWiST benefits (11.1 vs 9.8 months; 95% CI of gain: 0.2-2.6), with a relative Q-TWiST gain of 10.8% (ranging from 6.4% to 15.1% in threshold analysis). In the ⩾70 years age group, nab-PC showed similar, but non-significant, ORR, PFS, and Q-TWiST benefits and significantly improved OS and QoL. Nab-PC as first-line therapy in older patients with advanced NSCLC increased ORR, OS, and QoL and resulted in quality-adjusted survival gains compared with standard sb-PC.British Journal of Cancer advance online publication, 2 June 2015; doi:10.1038/bjc.2015.181
    British Journal of Cancer 06/2015; 113(1). DOI:10.1038/bjc.2015.181 · 4.84 Impact Factor
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    ABSTRACT: Therapies targeted to the immune checkpoint mediated by PD-1 and PD-L1 show antitumor activity in a subset of patients with non-small cell lung cancer (NSCLC). We have now examined PD-L1 expression and its regulation in NSCLC positive for the EML4-ALK fusion gene. The expression of PD-L1 at the protein and mRNA levels in NSCLC cell lines was examined by flow cytometry and by reverse transcription and real-time PCR analysis, respectively. The expression of PD-L1 in 134 surgically resected NSCLC specimens was evaluated by immunohistochemical analysis. The PD-L1 expression level was higher in NSCLC cell lines positive for EML4-ALK than in those negative for the fusion gene. Forced expression of EML4-ALK in Ba/F3 cells markedly increased PD-L1 expression, whereas endogenous PD-L1 expression in EML4-ALK-positive NSCLC cells was attenuated by treatment with the specific ALK inhibitor alectinib or by RNA interference with ALK siRNAs. Furthermore, expression of PD-L1 was down-regulated by inhibitors of the MEK-ERK and PI3K-AKT signaling pathways in NSCLC cells positive for either EML4-ALK or activating mutations of the epidermal growth factor receptor (EGFR). Finally, the expression level of PD-L1 was positively associated with the presence of EML4-ALK in NSCLC specimens. Our findings that both EML4-ALK and mutant EGFR up-regulate PD-L1 by activating PI3K-AKT and MEK-ERK signaling pathways in NSCLC reveal a direct link between oncogenic drivers and PD-L1 expression. Copyright © 2015, American Association for Cancer Research.
    Clinical Cancer Research 05/2015; 21(17). DOI:10.1158/1078-0432.CCR-15-0016 · 8.72 Impact Factor
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    ABSTRACT: Human epidermal growth factor receptor (HER) 3 is aberrantly overexpressed and correlates with poor prognosis in non-small cell lung cancer (NSCLC). Patritumab is a monoclonal antibody against HER3 that has shown promising results in early-phase clinical trials, but an optimal target population for the drug has yet to be identified. In the present study, we examined whether heregulin, a HER3 ligand that is also overexpressed in a subset of NSCLC, can be used as a biomarker to predict the antitumorigenic efficacy of patritumab and whether the drug can overcome the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) resistance induced by heregulin. Patritumab sensitivity was associated with heregulin expression, which, when abolished, resulted in the loss of HER3 and AKT activation and growth arrest. Furthermore, heregulin overexpression induced EGFR TKI resistance in NSCLC cells harbouring an activating EGFR mutation, while HER3 and AKT activation was maintained in the presence of erlotinib in heregulin-overexpressing, EGFR-mutant NSCLC cells. Sustained HER3-AKT activation was blocked by combining erlotinib with either anti-HER2 or anti-HER3 antibody. Notably, heregulin was upregulated in tissue samples from an NSCLC patient who had an activating EGFR mutation but was resistant to the TKI gefitinib. These results indicate that patritumab can overcome heregulin-dependent EGFR inhibitor resistance in NSCLC in vitro and in vivo and suggest that it can be used in combination with EGFR TKIs to treat a subset of heregulin-overexpressing NSCLC patients.Oncogene advance online publication, 11 May 2015; doi:10.1038/onc.2015.142.
    Oncogene 05/2015; DOI:10.1038/onc.2015.142 · 8.46 Impact Factor
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    ABSTRACT: The mutation of T790M in EGFR is a major mechanism of resistance to treatment with EGFR-TKIs. Only qualitative detection (presence or absence) of T790M has been described to date, however. Digital PCR (dPCR) analysis has recently been applied to the quantitative detection of target molecules in cancer with high sensitivity. In the present study, 25 tumor samples (13 obtained before and 12 after EGFR-TKI treatment) from 18 NSCLC patients with activating EGFR mutations were evaluated for T790M with dPCR. The ratio of the number of T790M alleles to that of activating mutation alleles (T/A) was determined. dPCR detected T790M in all 25 samples. Although T790M was present in all pre-TKI samples from 13 patients, 10 of these patients had a low T/A ratio and manifested substantial tumor shrinkage during treatment with EGFR-TKIs. In six of seven patients for whom both pre- and post-TKI samples were available, the T/A ratio increased markedly during EGFR-TKI treatment. Highly sensitive dPCR thus detected T790M in all NSCLC patients harboring activating EGFR mutations whether or not they had received EGFR-TKI treatment. Not only highly sensitive but also quantitative detection of T790M is important for evaluation of the contribution of T790M to EGFR-TKI resistance.
    Oncotarget 05/2015; 6(24). DOI:10.18632/oncotarget.4058 · 6.36 Impact Factor
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    ABSTRACT: The standard diagnostic method for echinoderm microtubule-associated protein-like 4-anaplastic lymphoma receptor tyrosine kinase translocation is fluorescence in situ hybridization (FISH). Recently, immunohistochemistry (IHC) has been reported as a potential method in screening for anaplastic lymphoma kinase (ALK)-positive non-small-cell lung carcinomas (NSCLC), whereas several authors have reported a discordance between FISH and IHC results. We investigated the heterogeneity of ALK gene rearrangement in excision specimens by FISH and also examined whether the FISH score of ALK gene rearrangement corresponded in excision and biopsy samples from the same patient. Twenty ALK IHC-positive patients including six patients treated with crizotinib therapy were evaluated for the presence of ALK FISH. For evaluation of heterogeneity of ALK gene rearrangement in excision specimens, we defined six to 10 observation areas in each case, and the number of ALK FISH positive observation areas (≥15% rearrangement detected) was investigated. ALK FISH score in small biopsy samples was classified as positive (≥15% rearrangement detected), equivocal (5-14% rearrangement detected), or negative (<4% rearrangement detected). Of a total of 64 tumor observation areas from nine excision specimens, 50 areas were positive for ALK gene rearrangement (81.8%). In the comparison of excision and small biopsy samples, all excision specimens were ALK FISH-positive (100%; 6 of 6), whereas only three of the small biopsy samples in these patients were positive (50%; 3 of 6), two were equivocal (33%; 2 of 6), and one was negative (17%; 1 of 6). The two equivocal patients received crizotinib and showed a response. ALK gene rearrangement heterogeneity was observed in NSCLC specimens by FISH. Our findings suggested that IHC-positive/FISH-equivocal cases should not be considered true "false-negatives" when a small biopsy sample was used for ALK analysis.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 05/2015; 10(5):800-5. DOI:10.1097/JTO.0000000000000507 · 5.28 Impact Factor
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    ABSTRACT: Crizotinib was the first clinically available inhibitor of the tyrosine kinase ALK, and next-generation ALK inhibitors, such as alectinib, are now under development. Although crizotinib is generally well tolerated, severe esophageal injury has been reported as a rare but serious adverse event of crizotinib therapy. We now describe the successful treatment with alectinib of a patient who developed crizotinib-induced esophageal ulceration. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Lung cancer (Amsterdam, Netherlands) 03/2015; 88(3). DOI:10.1016/j.lungcan.2015.03.012 · 3.96 Impact Factor
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    ABSTRACT: The epidermal growth factor family (EGF) has been suggested to influence the sensitivity to anti-epidermal growth factor receptor therapy. We examined the correlation between circulating levels of the epidermal growth factors amphiregulin and transforming growth factor-α (TGF-α) and the MET ligand hepatocyte growth factor and sensitivity to the anti-epidermal growth factor receptor antibody in colorectal cancer (CRC) patients. Plasma levels of each ligand were measured by enzyme-linked immunosorbent assay in 51 patients with wild-type KRAS CRC. Patients with high hepatocyte growth factor (HGF) levels had a significantly lower disease control rate (DCR) and shorter median progression-free survival (PFS) and overall survival (OS) than those with low expression levels. Amphiregulin was correlated with objective response rate (ORR) but not with PFS or OS. Cetuximab response and survival were not associated with TGF-α. Circulating HGF may help identify CRC patients most likely to benefit from anti-epidermal growth factor receptor antibody therapy. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.
    Anticancer research 03/2015; 35(3):1683-9. · 1.83 Impact Factor
  • Masayuki Takeda · Isamu Okamoto · Kazuhiko Nakagawa ·
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    ABSTRACT: Objectives: Three epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) - afatinib, erlotinib, and gefitinib - are available for the treatment of patients with EGFR mutation-positive non-small cell lung cancer (NSCLC). Given the long-term exposure of such patients to EGFR-TKIs, the toxicological properties of these agents in these individuals may differ from those observed in unselected patients. We compared the frequencies of severe adverse events (AEs) among EGFR mutation-positive NSCLC patients treated with these three EGFR-TKIs. Materials and methods: We performed a pooled analysis of severe AEs according to the type of EGFR-TKI administered with the use of data extracted from prospective clinical trials that evaluated the clinical efficacy of gefitinib, erlotinib, or afatinib in NSCLC patients with EGFR mutations. Results: Twenty-one trials published between 2006 and 2014 and including 1468 patients were eligible for analysis. Patients in 13 trials (n=457) received gefitinib, those in 5 trials (n=513) received erlotinib, and those in 3 trials (n=498) received afatinib. Rash and diarrhea of grade ≥3 were significantly more frequent with afatinib therapy than with erlotinib or gefitinib therapy. The frequency of interstitial lung disease (ILD) of grade ≥3 was low (0.6-2.2%) with all three EGFR-TKIs and did not differ significantly among them. Gefitinib was associated with a significantly higher frequency of hepatotoxicity of grade ≥3 compared with erlotinib or afatinib. The overall frequency of AEs leading to treatment withdrawal was 6.1% (83 of 1354 evaluable patients), with such AEs occurring significantly more often with afatinib or gefitinib than with erlotinib. The most common withdrawal AEs were skin toxicity, ILD, and hepatotoxicity. Conclusion: Such information on AEs should facilitate selection of the most appropriate EGFR-TKI for EGFR mutation-positive NSCLC patients with regard to mitigation of the risk for certain types of toxicity.
    Lung Cancer 02/2015; 88(1). DOI:10.1016/j.lungcan.2015.01.026 · 3.96 Impact Factor
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    ABSTRACT: Objectives: Given our previously published study, α 1 nicotinic acetylcholine receptor (nAChR) plays an essential role in nicotine-induced cell signaling and nicotine-induced resistance to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) in non-small cell lung cancer (NSCLC) PC9 cells. The aim of this study was to investigate the potential mechanism between nAChR and EGFR for nicotine-induced resistance to EGFR-TKI erlotinib in the NSCLC xenograft model. Materials and methods: We identified the role of nicotine to EGFR/AKT/ERK pathways and to erlotinib-resistance in NSCLC PC9 and HCC827 cells by MTS assay and western blot. Then, we established the PC9 xenograft model with nicotine exposure and treated mice with erlotinib combined with vehicle or nicotine. Results: We confirmed the effects of nicotine on EGFR/AKT/ERK pathways and determined nicotine's potential in preventing from the effect of erlotinib on NSCLC cells. Then, we showed that nicotine exposures can promote tumor growth and induce resistance to erlotinib in the PC9 xenograft model. Our results also indicated that chronic oral administration of nicotine can cause more significant erlotinib-resistance compared with acute i.v. injection of nicotine through activating α 1 nAChR and EGFR pathways. Conclusions: These results suggest that nicotine contributes to the progression and erlotinib-resistance of the NSCLC xenograft model via the cooperation between nAChR and EGFR.
    Lung Cancer 01/2015; 88(1). DOI:10.1016/j.lungcan.2015.01.017 · 3.96 Impact Factor
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    ABSTRACT: Nearly half of all cases of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for non–small-cell lung cancer (NSCLC) are due to the T790M mutation in EGFR exon 20. The T790M mutation is a C → T transition mutation at a CpG dinucleotide. DNA methylation of cytosine (5-methylcytosine; 5-mC) in CpG dinucleotides is a common DNA modification; CpG dinucleotides are considered to be mutational hotspots that cause genetic diseases and cancers through spontaneous deamination of 5-mC, resulting in C → T transition mutations. This study aimed to examine the methylation level of cytosine of EGFR codon 790 and investigate whether DNA methylation was involved in acquiring the T790M mutation. We examined 18 NSCLC tumor tissues, 7 normal lymph node tissues and 4 NSCLC cell lines (PC9, HCC827, 11-18 and A549). 5-mC was checked by bisulfite sequencing and quantified by pyrosequencing. We found that all tissue samples and cell lines had 5-mC in EGFR codon 790. The 5-mC range was 58.4–90.8%. Our results imply that hypermethylation of the CpG dinucleotide in EGFR codon 790 leads to the C → T transition mutation, causing resistance to EGFR-TKI treatment.
    Cancer Genetics 01/2015; 208(5). DOI:10.1016/j.cancergen.2014.12.005 · 2.98 Impact Factor
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    ABSTRACT: Hepatocyte growth factor (HGF) expression is a poor prognostic factor in various types of cancer. Expression levels of HGF have been reported to be regulated by shorter poly(dA) sequences in the promoter region. In the present study, the poly(dA) mononucleotide tract in various types of human cancer cell lines was examined and compared with the HGF expression levels in those cells. Short deoxyadenosine repeat sequences were detected in five of the 55 cell lines used in the present study. The H69, IM95, CCK-81, Sui73 and H28 cells exhibited a truncated poly(dA) sequence in which the number of poly(dA) repeats was reduced by ≥5 bp. Two of the cell lines exhibited high HGF expression, determined by reverse transcription quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. The CCK-81, Sui73 and H28 cells with shorter poly(dA) sequences exhibited low HGF expression. The cause of the suppression of HGF expression in the CCK-81, Sui73 and H28 cells was clarified by two approaches, suppression by methylation and single nucleotide polymorphisms in the HGF gene. Exposure to 5-Aza-dC, an inhibitor of DNA methyltransferase 1, induced an increased expression of HGF in the CCK-81 cells, but not in the other cells. Single-nucleotide polymorphism (SNP) rs72525097 in intron 1 was detected in the Sui73 and H28 cells. Taken together, it was found that the defect of poly(dA) in the HGF promoter was present in various types of cancer, including lung, stomach, colorectal, pancreas and mesothelioma. The present study proposes the negative regulation mechanisms by methylation and SNP in intron 1 of HGF for HGF expression in cancer cells with short poly(dA).
    Oncology letters 01/2015; 9(1):405-410. DOI:10.3892/ol.2014.2702 · 1.55 Impact Factor
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    ABSTRACT: Amatuximab is a chimeric monoclonal antibody that targets mesothelin, which is expressed in virtually all mesotheliomas and pancreatic adenocarcinomas. The objective of this study was to determine the dose-limiting toxicity and the maximum tolerated dose. Patients with mesothelioma, pancreatic adenocarcinoma or other mesothelin-positive solid tumors were eligible for this study. Amatuximab was administered weekly as an intravenous infusion in 4-week cycles at progressively increasing doses ranging from 50 to 200 mg/m2. Seventeen patients received amatuximab. Two dose-limiting toxicities were observed: one at 50 mg/m2 and one at 200 mg/m2; the maximum tolerated dose of this study was determined to be 200 mg/m2. Of the 17 patients, 13 patients (76.5 %) experienced treatment-related adverse events. The most common adverse events were grade 1 fatigue (29.4 %) and pyrexia (23.5 %). The maximum serum concentration and area under the concentration curve values increased in an almost dose-proportional manner. Three patients had stable disease. Amatuximab was generally well tolerated at doses up to 200 mg/m2. The pharmacokinetic profile of amatuximab in the Japanese population was similar to that seen in the United States population (Clinical Identifier: NCT01018784).
    Investigational New Drugs 12/2014; 33(2). DOI:10.1007/s10637-014-0196-0 · 2.92 Impact Factor

Publication Stats

7k Citations
1,346.82 Total Impact Points


  • 2014-2015
    • Kyushu University
      • Graduate School of Medical Sciences
      Hukuoka, Fukuoka, Japan
    • Aichi Cancer Center
      Nagoya, Aichi, Japan
  • 2006-2015
    • Kinki University
      • Faculty of Medicine
      Ōsaka, Ōsaka, Japan
  • 2013
    • Chiba Cancer Center
      Tiba, Chiba, Japan
  • 1999-2006
    • Kumamoto University
      • • Graduate School of Medical Sciences
      • • Department of Tumor Genetics and Biology
      • • School of Medicine
      Kumamoto, Kumamoto, Japan
    • National Cancer Institute (USA)
      • Basic Research Laboratory
      Maryland, United States
  • 2004
    • National Institutes of Health
      • Basic Research Laboratory
      Bethesda, MD, United States
  • 2002-2003
    • Thomas Jefferson University
      • Department of Microbiology & Immunology
      Filadelfia, Pennsylvania, United States