Hirotaka Sugiyama

Application of drug delivery system to boron neutron capture therapy for cancer

Background: Tumor cell destruction in boron neutron capture therapy (BNCT) is due to the nuclear reaction between 10B and thermal neutrons (10B + 1n → 7Li + 4He (α) + 2.31 MeV (93.7 %)/2.79 MeV (6.3 %)). The resulting lithium ions and αparticles are high linear energy transfer (LET) particles which give a high biological effect. Their short range in tissue (5 – 9 μm) restricts radiation damage to those cells in which boron atoms are located at the time of neutron irradiation. BNCT has been applied clinically for the treatment of malignant brain tumors, malignant melanoma, head and neck cancer and hepatoma. Sodium mercaptoundecahydro-dodecaborate (Na210B12H11SH: BSH) and borono-phenylalanine (10BPA) are currently being used in clinical treatments. These low molecule compounds are easily cleared from cancer cells and blood, so high accumulation and selective delivery of boron compounds into tumor tissues and cancer cells are most important to achieve effective BNCT and to avoid damage to adjacent healthy cells. Objective: In order to achieve the selective delivery of boron atoms to cancer cells, a drug delivery system (DDS) is an attractive intelligent technology for targeting and controlled release of drugs. Methods: We performed literature searches related to boron delivery systems in vitro and in vivo Results: We describe several DDS technologies for boron delivery to cancer tissues and cancer cells from the past to current status. We are convinced that it will be possible to use liposomes, monoclonal antibodies and WOW emulsions as boron delivery systems for BNCT clinically in accordance with the preparation of good commercial product (GCP) grade materials.

Improvement of sensitivity to platinum compound with siRNA knockdown of upregulated genes in platinum complex-resistant ovarian cancer cells in vitro.

It is known that some cancers show platinum complex resistance and that others show platinum complex sensitivity among ovarian cancers. Oxaliplatin (cis-[oxalato[trans-l-1, 2-diamino-cyclohexane] platinum[II]]; l-OHP), an active anti-cancer agent consisting of platinum, inhibits RNA synthesis and results in cytostatic effects. We investigated the difference between an oxaliplatin-resistant ovarian cancer cell line, KFR, and an oxaliplatin-sensitive ovarian cancer cell line, KF-1, using DNA microarray analysis. The oxaliplatin-resistant cell line, KFR, was established by using KF-1 cells derived from human serous cystadenocarcinoma of the ovary. Acquisition of platinum resistance in human ovarian cancer cells thus appeared to be related mainly to the expression of gamma-glutamylcysteine synthetase (gamma-GCS), topo II and metallothionein (hMT) genes, and partly to that of topo I and glutathione S-transferase--pi (GST-pi) genes, in addition to a decrease in platinum accumulation. KFR cells had 8.5- and 24.7-fold higher mRNA levels of gamma-glutamylcysteine synthetase (gamma-GCS), and topo II genes than KF-1 cells, while KFR had only a slight increase in the glutathione S-transferase--pi (GST-pi) mRNA level as compared with KF-1. In comparison of the gene expressions between KFR and KF-1 ovarian cancer cell lines, tubulin-specific chaperone E (TBCE) and CBP/p300-interacting transactivator (CITED2) were overexpressed in KFR compared to KF-1. These genes are overexpressed in MKN74, an oxaliplatin-resistant gastric cancer cell line, compared to MKN28, an oxaliplatin-sensitive gastric cancer cell line. TBCE is 13-fold increased in KFR cells compared to KF-1 cells. CBP/p300-interacting transactivator is increased 2-fold in KFR cells compared to KF-1 cells. The siRNA directed to the TBCE gene and CBP/p300-interacting transactivator gene enhanced the cytotoxicity of diplatin to the platinum-resistant ovarian cancer cell line KFR. These results show that the TBCE gene and CBP/p300 gene have potential as multidrug-resistant genes. It is necessary to check the effect of siRNA to influx or exflux. It has potential to enhance the effect of anti-cancer agents to resistant cancer cells, so we will proceed to develop an inhibitor of these TBCE and CBP/p300 proteins.

Feasibility evaluation of neutron capture therapy for hepatocellular carcinoma using selective enhancement of boron accumulation in tumour with intra-arterial administration of boron-entrapped water-in-oil-in-water emulsion.

INTRODUCTION Hepatocellular carcinoma (HCC) is one of the most difficult to cure with surgery, chemotherapy, or other combinational therapies. In the treatment of HCC, only 30% patients can be operated due to complication of liver cirrhosis or multiple intrahepatic tumours. Tumour cell destruction in boron neutron-capture therapy (BNCT) is due to the nuclear reaction between (10)B atoms and thermal neutrons, so it is necessary to accumulate a sufficient quantity of (10)B atoms in tumour cells for effective tumour cell destruction by BNCT. Water-in-oil-in-water (WOW) emulsion has been used as the carrier of anti-cancer agents on intra-arterial injections in clinical. In this study, we prepared (10)BSH entrapped WOW emulsion by double emulsifying technique using iodized poppy-seed oil (IPSO), (10)BSH and surfactant, for selective intra-arterial infusion to HCC, and performed simulations of the irradiation in order to calculate the dose delivered to the patients. MATERIALS AND METHODS WOW emulsion was administrated with intra-arterial injections via proper hepatic artery on VX-2 rabbit hepatic tumour models. We simulated the irradiation of epithermal neutron and calculated the dose delivered to the tissues with JAEA computational dosimetry system (JCDS) at JRR4 reactor of Japan Atomic Research Institute, using the CT scans of a HCC patient. RESULTS AND DISCUSSIONS The (10)B concentrations in VX-2 tumour obtained by delivery with WOW emulsion were superior to those by conventional IPSO mix emulsion. According to the rabbit model, the boron concentrations (ppm) in tumour, normal liver tissue, and blood are 61.7, 4.3, and 0.1, respectively. The results of the simulations show that normal liver biologically weighted dose is restricted to 4.9 Gy-Eq (CBE; liver tumour: 2.5, normal liver: 0.94); the maximum, minimum, and mean tumour weighted dose are 43.1, 7.3, and 21.8 Gy-Eq, respectively, in 40 min irradiation. In this study, we show that (10)B entrapped WOW emulsion could be applied to novel intra-arterial boron delivery carrier for BNCT, and we show the possibility to apply BNCT to HCC. We can irradiate tumours as selectively and safety as possible, reducing the effects on neighbouring healthy tissues.

Dosimetric evaluation of neutron capture therapy for local advanced breast cancer

Local recurrence breast cancer is one of the most difficult conditions to cure and there is a need for new therapy. If sufficient boron compound can be targeted to the tumor, boron neutron capture therapy (BNCT) can be applied to local recurrent breast cancer. In this study, we performed a preliminary dosimetry with a phantom model of the mammary gland at Kyoto University Research Reactor (KUR), and a feasibility dosimetry with JAERI Computational Dosimetry System (JCDS) at JRR4 reactor of Japan Atomic Research Institute. We performed preliminary dosimetry of a phantom model of the mammary gland with thermal neutron irradiation (OO-0011 mode) on LiF collimation at KUR. The thermal neutron flux was 5.16 E+08 cm(-2)s(-1) at the surface of phantom. The blood boron concentration is estimated to be 30 ppm; tumor boron concentration is also estimated to be 90 ppm according to tumor/blood ratio 3 and skin/blood ratio 1.2. Tumor RBE dose is estimated to be 47 Gy/h, and skin RBE dose is 12.4 Gy/h. In case of advanced breast cancer, we performed the feasibility estimation of 3D construction of tumor according to the MRI imaging of a patient with epithermal neutron mode at JRR4. The blood boron concentration (ppm) and tumor/normal tissue ratio are estimated to be 24 and 3.5, respectively. Skin RBE dose is restricted to 10 Gy/h, the maximum tumor RBE dose, minimum tumor RBE dose, and mean tumor RBE dose are 42.2, 11.3, and 28.9 Gy-Eq, respectively, in half hour irradiation. In this study, we showed the possibility to apply BNCT to local recurrent breast cancer. We can irradiate tumors selectively and as safely as possible, reducing the effects on neighboring healthy tissues.

Abstract 2676: Feasible evaluation of neutron capture therapy for local recurrenced breast cancer according to boron uptake in tumour with estimating by F-BPA positron emission tomograpy

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Local recurrenced breast cancer is one of the most difficult neoplasms to cure and there is a need for new combinated therapy. If sufficient boron compound can be targeted accurate to the tumour, Boron Neutron Capture Therapy (BNCT) can be applied to local recurrenced breast cancer. We are planning BNCT to patients of local recurrenced breast cancer. In this study, we performed a feasibility thermal neutron dosimetry with JCDS at JRR4 reactor of Japan Atomic Research Institute according to boron uptake in tumour with estimating by 18F-BPA positron emission tomograpy(PET). Recently, positron emission tomograpy is commonly used for primary detection and metastasis of cancers. In the fields of BNCT, 18F labeled borono-phenylalanine(BPA)-PET are also spread to applyed to evaluate the accumulation of boron atoms to tumours and the actibity of cancer cells. We experienced the 18F-BPA PET for the case of breast cancer patients who had metastased to right supraclaviclar lymph node. [Case] The 55 y.o. patient was performed modified radical mastectomy with lymph node dissection (Patey’ s method). After 3 years later, right cervical LN metastasis was occured, and the patients was administrated Capecitabine (2400mg/day for 21 days, and one week rest), or TS-1(tegafur, gimeracil, oteracil potassium, 100mg/ day), Herceptin(firstly 228mg, and then 114mg per week), or medroxyprogesterone(1200 mg/day). The high accumulating images of metastased to right supraclaviclar lymph node was acquired by 18F-BPA PET. The tumour / blood ratio was 2.26. There was no other active images in the body. In case of advanced breast cancer, we performed the feasibility estimation of 3D construction of tumour according to the PET-CT imaging of a patient with epithermal neutron mode at JRR4. The thermal neutron flux was 1.145×10E+09 cm-2s-1 at the surface of 3D body images in simulation according to the CT images. The blood boron concentration (ppm) and tumour/normal tissue ratio are estimated to 24, 2.26, respectively. Tumour RBE is estimated to 3.8 Gy/h, and skin RBE is 2.5 Gy/h. Skin RBE dose is ristricted to 10 Gy-Eq, the maximum tumour RBE dose, minimum tumour RBE dose, and mean tumour RBE dose are 38.5, 19.9, and 30.6 Gy-Eq, respectively, in 40 minutes irradiation. In this study, we showed the possibility to apply BNCT to local recurrenced advanced breast cancer with the themal neutron dosimetry for BNCT according to boron uptake in tumour with estimating by F-BPA PET. We can irradiate tumours selectively and safety as possible, reducing the effects on neighboring healthy tissues by using BNCT. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2676. doi:10.1158/1538-7445.AM2011-2676

Establishment of a natural suppressor cell line producing soluble suppressor factor other than transforming growth factor-beta.

Natural suppressor (NS) cell line (Clone 59) was established from the bone marrow of adult C3H/Hej mice in the presence of WEHI‐3 conditioned media. Clone 59 cells suppressed the generation of cytotoxic T lymphocytes from normal mouse spleen. This suppression was seen at a responder‐to‐suppressor cell ratio of 1000:1 and lacked antigen specificity or MHC restriction. Clone 59 cells expressed the ‘null’ surface phenotype (Thyl.2−, CD3−, Lyt‐2−, L3T4 −, surface Ig−, MAC–l−) by immunofluorescent staining. Clone 59 cells exhibited no cytolytic activity against NK cell‐sensitive YAC‐1 and natural cytotoxic L929 target cell lines. Non‐specific suppression, with a cell‐free supernatant from the Clone 59‐NS cells, also was observed. The supernatant did not inhibit [3H]‐thymidine uptake by CTLL‐2 cells which were proliferating in response to IL‐2. Anti‐transforming growth factor‐β (TGF‐β) monoclonal antibody had no effect on suppression, suggesting that the non‐specific suppression is mediated by some soluble factors other than TGF‐β. Clone 59 cells may be useful in identifying non‐specific suppressor cells in adult bone marrow and studying their functional role in the regulation of tolerance and self‐reactivity.

Selective boron delivery by intra-arterial injection of BSH-WOW emulsion in hepatic cancer model for neutron capture therapy

OBJECTIVE Boron neutron-capture therapy (BNCT) has been used to inhibit the growth of various types of cancers. In this study, we developed a 10BSH-entrapped water-in-oil-in-water (WOW) emulsion, evaluated it as a selective boron carrier for the possible application of BNCT in hepatocellular carcinoma treatment. METHODS We prepared the 10BSH-entrapped WOW emulsion using double emulsification technique and then evaluated the delivery efficacy by performing biodistribution experiment on VX-2 rabbit hepatic tumour model with comparison to iodized poppy-seed oil mix conventional emulsion. Neutron irradiation was carried out at Kyoto University Research Reactor with an average thermal neutron fluence of 5 × 1012 n cm-2. Morphological and pathological analyses were performed on Day 14 after neutron irradiation. RESULTS Biodistribution results have revealed that 10B atoms delivery with WOW emulsion was superior compared with those using iodized poppy-seed oil conventional emulsion. There was no dissemination in abdomen or lung metastasis observed after neutron irradiation in the groups treated with 10BSH-entrapped WOW emulsion, whereas many tumour nodules were recognized in the liver, abdominal cavity, peritoneum and bilateral lobes of the lung in the non-injected group. CONCLUSION Tumour growth suppression and cancer-cell-killing effect was observed from the morphological and pathological analyses of the 10BSH-entrapped WOW emulsion-injected group, indicating its feasibility to be applied as a novel intra-arterial boron carrier for BNCT. Advances in knowledge: The results of the current study have shown that entrapped 10BSH has the potential to increase the range of therapies available for hepatocellular carcinoma which is considered to be one of the most difficult tumours to cure.

Probabilistic Approach to Rationalization of Plants Maintenance.

Since there are a lot of equipments in large plants, their safety and reliability cannot be kept as high level as designed without maintenance activities. Then preventive maintenance is intensively executed in some large plants. However, it will be inefficient to perform the preventive maintenance blindly. To make maintenance activities effective, it is essential to identify the critical equipments influencing plant safety and/or reliability and carry out the maintenance by focusing attentions on these equipments. It needs quantitative analyses to identify the critical equipments based on the data of failure rates. However, complete data set of failure rates cannot necessarily be available for some plants such as nuclear power plants. In this study, we carry out the reliability analysis for generic LNG plant and calculate various quantitative risk importance measures for each equipment. We propose rather qualitative representations for some quantitative measures, considering the situation without complete data set and conclude that it is possible to rationalize maintenance procedure by using these rather qualitative measures, though the level of rationalization is of course limited.

Simulation of Magnetization of Bi2212 Single Crystal by the Fluxoid Dynamics Method

In this study the Fluxoid Dynamics (FD) method was developed to simulate the mesoscopic behavior of the fluxoids in a Bi2212 single crystal. This method is based on a combination of two concepts; the Molecular Dynamics (MD) and the Ginzburg-Landau (G-L) theory. The aim of this study is to predict the macroscopic electromagnetic phenomena by simulating the mesoscopic behavior of many fluxoids.