Sachio Maehara

Tokyo Medical University, Tokyo, Tokyo-to, Japan

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Publications (18)46.28 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: PDT induces apoptosis, inflammatory reactions, immune reactions, and damage to the microvasculature around the tumors. The mechanisms responsible for the anticancer effects of Photofrin-PDT and NPe6-PDT differ somewhat. To select a photosensitizer for lung cancer treatment and to improve the efficacy of PDT, the mechanisms of action for PDT using Photofrin or NPe6 must be elucidated and the phenomena validated by analyzing molecular determinants from clinical samples. We examined the role of immunological reactions in the anti-tumor effects of PDT using cytokine-overexpressing cells and investigated whether the anti-apoptotic protein Bcl-2 may be a molecular target. Moreover, we investigated the association between ATP-binding cassette transporter proteins such as breast cancer-resistant protein (BCRP), which can pump out some types of photosensitizer, and the efficacy of PDT using clinical samples from 81 early lung cancer lesions treated with PDT between 1998 and 2006 at the Tokyo Medical University Hospital. Photofrin-PDT damaged Bcl-2 and rapidly induced apoptosis, but NPe6-PDT did not damage Bc-2 nor did it induce morphologically typical apoptosis. However, NPe6-PDT exerted a strong anti-tumor effect, regardless of the overexpression of Bcl-2. By analyzing the BCRP-overexpressing cells, Photofrin, but not NPe6, was found to be a substrate of BCRP. All 81 lung cancer lesions were BCRP-positive; as Photofrin was found to be a substrate of BCRP, the expression of BCRP significantly affected the efficacy of Photofrin-PDT. However, NPe6-PDT exerted a strong antitumor effect regardless of BCRP expression, and the complete response rate after NPe6-PDT was much higher than that after Photofrin-PDT. Our translational research suggests that NPe6-PDT may be superior to Photofrin-PDT for the treatment of lung caner, and individualized approaches to PDT based on the expression status of Bcl-2 and/or BCRP may improve the efficacy of PDT in patients with lung cancers.
    Lasers in Surgery and Medicine 09/2011; 43(7):591-9. · 2.46 Impact Factor
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    ABSTRACT: Most centrally located early lung cancers (CLELC) <1.0 cm in diameter do not invade beyond the bronchial cartilage, and photodynamic therapy (PDT) with Photofrin is currently recommended as a treatment option for such lesions. NPe6 is a second-generation photosensitizer, and because it has a longer absorption band (664 nm) than Photofrin (630 nm), we hypothesized that NPe6-PDT would exert a strong antitumor effect against cancer lesions >1.0 cm in diameter, which are assumed to involve extracartilaginous invasion and to be unsuitable for treatment with Photofrin-PDT. Between June 2004 and December 2008, 75 patients (91 lesions) with CLELC underwent NPe6-PDT after the extent of their tumors had been assessed by fluorescence bronchoscopy for photodynamic diagnosis and tumor depth had been assessed by optical coherence tomography. Seventy cancer lesions < or =1.0 cm in diameter and 21 lesions >1.0 cm in diameter were identified, and the complete response rate was 94.0% (66 of 70) and 90.4% (19 of 21), respectively. After the mass of large tumors and deeply invasive tumors had been reduced by electrocautery, NPe6-PDT was capable of destroying the residual cancer lesions. NPe6-PDT has a strong antitumor effect against CLELCs >1.0 cm in diameter that have invaded beyond the bronchial cartilage, thereby enabling the destruction of residual cancer lesions after mass reduction of large nodular- or polypoid-type lung cancers by electrocautery. The PDT guidelines for lung cancers should therefore be revised because use of NPe6-PDT will enable expansion of the clinical indications for PDT.
    Clinical Cancer Research 03/2010; 16(7):2198-204. · 7.84 Impact Factor
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    ABSTRACT: Patients with centrally located early lung cancer (CLELC) are often heavy smokers with a considerably high risk of multiple primary lung cancer (MPLC) lesions; treatment strategies for such patients must preserve the cardiopulmonary function. Between July 2004 and July 2008, patients with CLELC underwent photodynamic therapy (PDT) using NPe6, second-generation photosensitizer at Tokyo Medical University Hospital. Among these patients, we retrospectively analyzed MPLC, which was treated by surgery plus PDT or PDT alone and examined the effectiveness of PDT, and we propose a treatment strategy for patients with MPLC. A total of 64 patients with CLECL received NPe6-PDT, and MPLCs were found in 22 patients (34.4%) using sputum cytology and a bronchoscopical examination using autofluorescence bronchoscopy. Among these 22 patients, 10 patients underwent surgery for primary lung cancer and underwent NPe6-PDT for the treatment of secondary primary CLELC, one patient underwent PDT for CLELC as a primary lesion followed by an operation for peripheral-type lung cancer as a secondary primary lesion, and 11 patients underwent PDT alone for MPLC lesions (28 lesions) that were roentgenographically occult lung cancers. Among these 22 patients with MPLC including peripheral-type lung cancers, which were resected by surgery, all 39 CLELC lesions exhibited a complete response after PDT, and all patients were alive. For patients with lung cancer with a long-term history of smoking, careful follow-up examinations after surgical resection are needed considering the incidence of metachronous primary lung cancers. PDT can play an important role for the treatment strategy for MPLC.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 11/2009; 5(1):62-8. · 4.55 Impact Factor
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    ABSTRACT: The ATP-binding cassette (ABC) transporter protein, BCRP (breast cancer resistance protein)/ABCG2 pumps out some types of photosensitizers used in photodynamic therapy (PDT) and causes resistance to the antitumor effect of PDT. The purpose of this study was to investigate the association between the expression of BCRP and the efficacy of PDT using Photofrin, or the second-generation photosensitizer, NPe6, for centrally located early lung cancers. Using human epidermoid carcinoma cells, A431 cells and the BCRP-overexpressing A431/BCRP cells, we examined the effects of BCRP expression on the effect of PDT by cell viability assay in vitro, and investigated the expression of BCRP by immunohistochemical analysis in 81 tumor samples obtained from patients with centrally located early lung cancers. The A431/BCRP cells were more resistant to Photofrin-PDT than A431 cells in vitro, and Fumitremorgin C, a specific inhibitor of BCRP, reversed the resistance. However, there was no significant difference in the antitumor effect of NPe6-PDT between these cells. All of the 81 centrally located early lung cancer lesions were BCRP-positive (2+, 45 lesions; 1+, 30 lesions) and all the patients were male and heavy smokers (>30 pack-years). The expression of BCRP significantly affected the efficacy of Photofrin-PDT in cancer lesions > or =10mm in diameter (P=0.04). On the other hand, NPe6-PDT exhibited a strong antitumor effect, regardless of the expression status of BCRP. Photofrin may be a substrate of BCRP and be pumped out from the cells, therefore, BCRP may be a molecular determinant of the outcome of Photofrin-PDT.
    Lung cancer (Amsterdam, Netherlands) 05/2009; 67(2):198-204. · 3.14 Impact Factor
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    ABSTRACT: It is very important to elucidate the mechanism of action and identify the molecular determinant of photodynamic medicine, in order to increase the number of clinical applications of photodynamic therapy (PDT) and perform personalized medicine. We have previously reported that PDT using some photosensitizers, such as phthalocyanine 4 (Pc 4) damages the anti-apoptotic protein Bcl-2, and that Bcl-2 is a molecular PDT target using a mitochondrion-targeting photosensitizer. In this study, we examined the molecular targets of Photofrin-PDT and NPe6-PDT, which are approved for early stage lung cancers by the Japanese Ministry of Health Labor and Welfare, by evaluating the photodamage to Bcl-2 using Western blot analysis. Our results showed that Photofrin-PDT damaged Bcl-2, induced morphologically typical apoptosis, and demonstrated equal sensitivity between MCF-7c3 cells (human breast cancer cells expressing stably transfected procaspase-3) and Bcl-2 overexpressing cells, MCF-7c3-GFP-Bcl-2 cells, with a clonogenic assay. However, NPe6-PDT did not damage Bcl-2 and took longer to induce typical apoptosis compared with Photofrin-PDT. MCF-7c3-GFP-Bcl-2 cells were considerably more resistant to the lethal effects of NPe6-PDT than parental MCF-7c3 cells. In conclusion, Photofrin-PDT damages different molecular targets, and our data indicate that the extent of Bcl-2 photodamage can determine the sensitivity of cancer cells to apoptosis and to overall cell killing caused by PDT using Photofrin, but not the lysosomal targeting NPe6. The application of these findings to clinical PDT may depend on the levels of the Bcl-2 proteins in the tumor being treated, and the tailor-made medicine based on the Bcl-2 photodamage may overcome any resistance afforded by elevated amounts of Bcl-2.
    International Journal of Oncology 11/2008; 33(4):689-96. · 2.66 Impact Factor
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    ABSTRACT: We report a case of left main bronchial glomus tumor in a 39-year-old man who presented with a cough he had had for 1 month. A computed tomography (CT) scan revealed a polypoid tumor in the membranous portion of the left main bronchus. The tumor showed marked enhancement on the early phase of dynamic contrast-enhanced CT, and it was thought to be a hypervascular tumor. The tumor was carefully resected by a rigid bronchoscope, and the pathological and immunohistochemical findings yielded a diagnosis of glomus tumor. Marked enhancement of early phase dynamic contrast-enhanced CT may be useful for a diagnosis of bronchial glomus tumor.
    Lung Cancer 05/2008; 60(1):132-5. · 3.39 Impact Factor
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    ABSTRACT: NPe6 is a novel second-generation photosensitizer used for photodynamic therapy (PDT). PDT using NPe6 and diode laser (664 nm) induces cell death, inflammatory reactions, immunological responses and damage to the microvasculature. In this study, we evaluated the influence of the immunological responses and of enhanced angiogenesis on the anti-tumor effect of NPe6-PDT using cytokine-overexpressing Lewis lung carcinoma (LLC), LLC-IL-2 cells both in vitro and in vivo. We showed by DNA microarray analysis in vitro that IL-2 and GADD-45alpha (growth arrest and DNA damage 45 alpha) mRNA expressions were induced by 3 h after NPe6-PDT applied at a dose killing 90% of the cells (LD90). IL-2-overexpressing cells (LLC/IL-2 cells) were resistant to the loss of clonogenicity as compared to the parental LLC cells in vitro. Furthermore, in female C57BL/6 mice, NPe6-PDT produced a cure rate of 66.7% in LLC tumors, whereas the cure rate was only 16.6% in LLC/IL-2 tumors, and overexpression of IL-2 caused failure of NPe6-PDT, with tumor recurrence, in vivo. These results suggest that IL-2 expression may play an unfavorable role in attenuation of the antitumor effect of NPe6-PDT. It has been reported that the expression of vascular endothelial growth factor (VEGF), in particular, may cause tumor recurrence after PDT and exert unfavorable effect in relation to attenuate the anti-tumor activity of PDT. Results of immunohistochemical analysis of LLC/IL-2 tumors have revealed that the expressions of GADD-45alpha and VEGF are induced in these tumors after PDT, and in particular, 12 h after PDT, the expression levels were much higher as compared with those in the LLC tumors. The results of our studies using in vitro and in vivo models suggest that the cell death caused by PDT was inhibited by induction of GADD-45alpha expression and that tumor recurrence was promoted by the enhancement of VEGF expression mediated by IL-2 upregulation. Therefore, it is speculated that the use of an IL-2 inhibitor may improve the efficacy of NPe6-PDT.
    International Journal of Oncology 03/2008; 32(2):397-403. · 2.66 Impact Factor
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    ABSTRACT: We had previously developed the possibility of use of a photodynamic diagnosis (PDD) system using a tumor-selective photosensitizer and laser irradiation for the early detection and photodynamic therapy (PDT) for centrally located early lung cancers. Recently, we established the autofluorescence diagnosis system integrated into a videoendoscope (SAFE-3000) as a very useful technique for the early diagnosis of lung cancer. Twenty-nine patients (38 lesions) with centrally located early lung cancer received PDD and PDT using the second-generation photosensitizer, talaporfin sodium (NPe6). Just before the PDT, we defined the tumor margin accurately using the novel PDD system SAFE-3000 with NPe6 and a diode laser (408nm). Red fluorescence emitted from the tumor by excitation of the photosensitizer by the diode laser (408nm) from SAFE-3000 allowed accurate determination of the tumor margin just before the PDT. The complete remission (CR) rate following NPe6-PDT in the cases with early lung cancer was 92.1% (35/38 lesions). We also confirmed the loss of red fluorescence from the tumors immediately after the PDT using SAFE-3000. We confirmed that all the NPe6 in the tumor had been excited and photobleached by the laser irradiation (664nm) and that no additional laser irradiation was needed for curative treatment. This novel PDD system using SAFE-3000 and NPe6 improved the quality and efficacy of PDT and avoided misjudgement of the dose of the photosensitizer or laser irradiation in PDT. PDT using NPe6 will become a standard option of treatments for centrally located early lung cancer.
    Lung Cancer 01/2008; 58(3):317-23. · 3.39 Impact Factor
  • Nihon Kikan Shokudoka Gakkai Kaiho 01/2008; 59(2):139-139.
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    ABSTRACT: Development of acquired resistance to gefitinib after an initial good response is common. Recently, it was reported that this acquired resistance is related to a secondary mutation associated with a substitution of threonine by methionine at codon 790 (T790M) of the epidermal growth factor receptor (EGFR) gene. In this report, we present a "never smoking" woman with advanced lung cancer who showed acquired resistance to gefitinib, and analysis of autopsy samples revealed no evidence of EGFR mutations in either exons 18-21 or codon 790, and positive immunostaining for breast cancer resistance protein (BCRP). We describe, for the first time, a case in which expression of BCRP was associated with acquired resistance to gefitinib, independent of EGFR mutations.
    Lung Cancer 12/2007; 58(2):296-9. · 3.39 Impact Factor
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    ABSTRACT: ATX-s10-Na(II) is a novel second-generation photo-sensitizer for photodynamic therapy (PDT). PDT using ATX-s10 and diode laser (670 nm) induces an apoptotic response, inflammatory reaction, immune reaction and damage to the microvasculature. In particular, the vascular shut-down effect plays an important role in the anti-tumor activity of ATX-s10-PDT. It has been reported that PDT induces hypoxia and expression of the vascular endothelial growth factor (VEGF) via the hypoxia-inducible factor 1 (HIF1)-alpha pathway. We hypothesized that the expression of VEGF may cause tumor recurrence after PDT and exert unfavorable effect against the anti-tumor activity of ATX-s10-PDT. In this study, we showed by DNA microarray analysis in vitro that VEGF mRNA expression was induced 3 h after laser irradiation in ATX-s10-PDT. We compared the anti-tumor activity of ATX-s10-PDT against lung cancer cell lines SBC-3 and SBC-3/VEGF, the latter overexpressing VEGF; there was no significant difference in the sensitivity to the PDT between the two cell lines as assessed by clonogenic assay. Furthermore, no statistically significant difference in the anti-tumor effect of PDT, as measured by tumor cures, was found between SBC-3 and SBC-3/VEGF tumors in female Balb/c-nu/nu nude mice in vivo. In conclusion, ATX-s10-PDT may prevent tumor recurrence despite induction of VEGF and promotion of tumor angiogenesis, which are known to enhance tumor proliferation and survival.
    Oncology Reports 10/2007; 18(3):679-83. · 2.30 Impact Factor
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    ABSTRACT: Because malignant mesothelioma is commonly seen as a diffuse neoplasm, a localized tumor is an extremely rare form of presentation. Only 45 cases have been reported, and little is known about their behavior. We report a new case of localized malignant mesothelioma with the microscopic appearance of diffuse malignant mesothelioma, but without any evidence of diffuse spread. A 54-year-old man, a former smoker, with a brief history of asbestos exposure for 3 months, presented with a severe right chest pain and a swelling in the same area. Chest-computed tomography (CT) showed a 4.5 cm extra pleural tumor with a smooth surface, located in the right anterior chest wall, and destruction of the 5th rib. A CT-guided needle biopsy revealed malignant mesothelioma. Detailed examinations revealed a resectable solitary localized mass with no distant metastasis. The patient underwent operation, a tumorectomy, plus a combined resection of the chest wall and part of the right middle lobe. A complete en bloc resection was achieved. Pathology revealed localized malignant mesothelioma, biphasic type. Immunohistochemical findings confirmed the mesothelial feature. Localized malignant mesothelioma should be distinguished from diffuse malignant mesothelioma because of its different biological behavior, and in the former complete resection it is associated with a good prognosis.
    Annals of thoracic and cardiovascular surgery: official journal of the Association of Thoracic and Cardiovascular Surgeons of Asia 09/2007; 13(4):262-6. · 0.47 Impact Factor
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    ABSTRACT: An abstract is unavailable. This article is available as HTML full text and PDF.
    Journal of Thoracic Oncology 07/2007; 2(8):S489. · 4.47 Impact Factor
  • Journal of Thoracic Oncology - J THORAC ONCOL. 01/2007; 2.
  • Nippon Laser Igakkaishi 01/2007; 28(4):355-361.
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    ABSTRACT: ATX-s10 is a novel and second-generation photosensitizer for photodynamic therapy (PDT). In order to conduct clinical trials of ATX-s10-PDT and/or extend its clinical applications, it is very important to elucidate the mechanisms of the action of ATX-s10-PDT. We examined the apoptic response against ATX-s10-PDT using a Bcl-2 or Bcl-2 mutant overexpressing cells. Using fluorescent microscopy, ATX-s10 localized not only to mitochondria but also to lysosomes and possibly other intracellular organelles, but not to the plasma membrane or the nucleus. These results suggest that ATX-s10-PDT can damage mitochondria and lysosomes. By Western blot analysis, ATX-s10-PDT damaged Bcl-2, which localized preferentially at mitochondrial membranes, and caused Bcl-2 to cross-link immediately after laser irradiation. However, ATX-s10-PDT was not able to rapidly induce morphologically typical apoptosis (i.e. chromatin condensation and fragmentation) as PDT using mitochondria targeted photosensitizers, such as phthalocyanine 4 (Pc 4). Pharmacological inhibitions of lysosomal cytokine protease cathepsins, such as cathepsin B and D, protected MCF-7c3 cells (human breast cancer cells expressing stably transfected procaspase-3) from apoptosis caused by ATX-s10-PDT. Overexpression of wild-type Bcl-2 or Bcl-2Delta33-54 resulted in relative resistance of cells to ATX-s10-PDT, as assessed by the degree of morphological apoptosis or loss of clonogenicity. We conclude that lysosomal damage by ATX-s10-PDT can initiate apoptotic response and this apoptotic pathway can be regulated by photodamage to Bcl-2 via mitochondrial damage.
    International Journal of Oncology 09/2006; 29(2):349-55. · 2.66 Impact Factor
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    ABSTRACT: We have been engaged in basic and clinical research on photodynamic therapy (PDT) and photodynamic diagnosis (PDD) for more than 25 years. PDT for 264 centrally located early-stage lung cancer lesions yielded an initial complete response (CR) rate of 84.8%. PDT is now becoming a standard option for centrally located stage 0 (TisN0M0) and stage I (T1N0M0) lung cancer. It is an attractive option for elderly patients in poor physical condition. Recent results of interstitial PDT for peripheral-type lung cancers suggest that it may be a promising local curative treatment modality for lesions less than 1.0 cm in diameter. In this article, we introduce our recent clinical trials of PDT for lung cancers (both central and peripheral), and new techniques of PDD in sentinel node navigation biopsy for breast cancers. Moreover, we introduce basic research on cancers and infectious diseases in order to expand the clinical applications of PDT.
    Lasers in Surgery and Medicine 07/2006; 38(5):371-5. · 2.46 Impact Factor
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    ABSTRACT: Postoperative empyema and aspergillosis were diagnosed in a 66-year-old man. Since non-operative therapy was not effective, we performed surgery. On the 8th postoperative day, a covered Ultraflex expandable stent (Boston Scientific, Galway, Ireland) was implanted to make a one-way airway for blocking a major air leak from a bronchopleural fistula causing respiratory distress. His general condition improved gradually, and he was discharged 30 days after stenting. In conclusion, we used a covered Ultraflex expandable stent to make an airway to block an air leak. This may be a new application for this stent.
    Annals of thoracic and cardiovascular surgery: official journal of the Association of Thoracic and Cardiovascular Surgeons of Asia 03/2006; 12(1):50-2. · 0.47 Impact Factor