Suppression of Tumor Growth in a Rabbit Hepatic Cancer Model by Boron Neutron Capture Therapy With Liposomal Boron Delivery Systems.

BACKGROUND/AIM: Tumor cell destruction by boron neutron capture therapy (BNCT) is attributed to the nuclear reaction between 10B and thermal neutrons. The accumulation of 10B atoms in tumor cells without affecting adjacent healthy cells is crucial for effective BNCT. We previously reported that several types of liposomal boron delivery systems (BDS) delivered effective numbers of boron atoms to cancer tissues, and showed tumor-growth suppression after thermal neutron irradiation. In the present study, we examined the effects of BNCT after intra-arterial infusion of 10B-borono-dodecaborate (10BSH) by liposomal BDS in rabbit hepatic cancer models. MATERIALS AND METHODS: We prepared 10BSH-entrapped transferrin-conjugated polyethylene glycol liposomes constructed with distearoyl-boron lipid (TF-PEG-DSBL), and performed thermal neutron irradiation at the Kyoto University Institute for Integrated Radiation and Nuclear Science after intra-arterial infusion into rabbit VX-2 hepatic tumors. RESULTS: Concentrations of 10B in VX-2 tumors on delivery with TF-PEG-DSBL liposomes reached 25 ppm on day 3 after the injection. Tumor growth was suppressed by thermal neutron irradiation after intra-arterial injection of this 10BSH-containing liposomal BDS, without damage to normal cells. CONCLUSION: The present results demonstrate the applicability of 10B-containing TF-PEG-DSBL liposomes as a novel intra-arterial boron carrier in BNCT for cancer.

Tumor Growth Suppression With Novel Intra-arterial Chemotherapy Using Epirubicin-entrapped Water-in-oil-in-water Emulsion In Vivo.

BACKGROUND/AIM: A mixture of anticancer agents and iodized poppy seed oil (IPSO) has been widely used for intra-arterial chemotherapy of hepatocellular carcinoma. However, the anticancer agents can easily separate from IPSO, so the therapeutic potential is limited. We developed epirubicin-entrapped water-in-oil-in-water emulsion (WOW-Epi) using a double-membrane emulsification technique. MATERIALS AND METHODS: We delivered WOW-Epi through a hepatic arterial injection to VX2 hepatic tumor rabbit model (1.2 mg/kg). RESULTS: VX2 tumor growth was selectively suppressed in the WOW-Epi-treated group compared with the control treated groups. The accumulation of WOW in nearby cancer cells was confirmed via electron-microscopy. Endocytosis seemed to be the mechanism underlying the uptake of WOW. CONCLUSION: WOW-Epi led to tumour growth suppression in vivo. WOW does not cause toxicity to arterial vessels. WOW-Epi will be hopefully used for repeated intra-arterial chemotherapy to HCC patients in the near future.

Single-dose toxicity study by intra-arterial injection of 10BSH entrapped water-in-oil-in-water emulsion for boron neutron capture therapy to hepatocellular carcinoma.

We developed a mixing medical device by attaching Shirasu porous glass Millipore membrane to prepare water-in-oil-in-water (WOW) emulsion in a shorter time to be applied as 10B-entrapped WOW emulsion for hepatocellular carcinoma (HCC) treatment. Single-dose toxicity studies by intra-arterial injection of 10BSH-entrapped WOW were performed in rabbits and pig, and no side effects were observed. We hope to proceed to the preclinical and clinical studies for further evaluation of 10B compound as multidisciplinary treatments for HCC.

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.

Pilot clinical study of boron neutron capture therapy for recurrent hepatic cancer involving the intra-arterial injection of a (10)BSH-containing WOW emulsion.

A 63-year-old man with multiple HCC in his left liver lobe was enrolled as the first patient in a pilot study of boron neutron capture therapy (BNCT) involving the selective intra-arterial infusion of a (10)BSH-containing water-in-oil-in-water emulsion ((10)BSH-WOW). The size of the tumorous region remained stable during the 3 months after the BNCT. No adverse effects of the BNCT were observed. The present results show that (10)BSH-WOW can be used as novel intra-arterial boron carriers during BNCT for HCC.

Tumor growth suppression by adenovirus-mediated introduction of a cell-growth-suppressing gene tob in a pancreatic cancer model.

TOB (transducer of ErbB-2) is a tumor suppressor that interacts with protein-tyrosine kinase receptors, including ErbB-2. Introduction of the tob gene into NIH3T3 cells results in cell growth suppression. In this study, we evaluated the effect of tob expression in pancreatic cell lines (AsPC-1, BxPC-3, SOJ) and discuss the tumor-suppressing effects of adenoviral vector expressing tob cDNA. We first measured the levels of endogenous tob mRNA being expressed in all pancreatic cancer cell lines. Then, we examined the effect of adenoviral vector containing tob cDNA (Ad-tob vector) on cancer cell lines. The viral vector was expanded with transfection in 293 cells. The titer of the vector was 350x10(6) pfu/ml. These cancer cells were able to be transfected with MOI 20 without adenoviral toxicity. The transfection of Ad-tob vector results in growth suppression of SOJ and AsPC-1 cell lines. The magnitude of the expression of the Ad-tob gene in cancer is correlated to tumor suppressive activity. We prepared pancreatic cancer peritonitis models using a peritoneal injection of AsPC-1 cells. In this model, bloody ascites and multiple tumor nodules were seen at the mesentery after 16 days. AdCAtob (50x10(6) pfu/day) was administered from day 5 to day 9 after 4 days of peritoneal injection of 2x10(6) AsPC-1 cells. Tumor growth suppression occurred 10 days after peritoneal injection of AdCAtob compared with the control group. There were no tumor nodules in the abdomen and no bloody ascites. These results suggest that the peritoneal injection of AdCAtob has potential to suppress the formation of pancreatic cancer peritonitis, and can be applied for chemotherapy-resistant cancer peritonitis.

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.