BNCT for primary synovial sarcoma.

Synovial sarcoma is a rare tumor requiring new treatment methods. A 46-year-old woman with primary monophasic synovial sarcoma in the left thigh involving the sciatic nerve, declining surgery because of potential dysfunction of the affected limbs, received two courses of BNCT. The tumor thus reduced was completely resected with no subsequent recurrence. The patient is now able to walk unassisted, and no local recurrence has been observed, demonstrating the applicability of BNCT as adjuvant therapy for synovial sarcoma. Further study and analysis with more experience accumulation are needed to confirm the real impact of BNCT efficacy for its application to synovial sarcoma.

Usefulness of combination with both continuous administration of hypoxic cytotoxin and mild temperature hyperthermia in boron neutron capture therapy in terms of local tumor response and lung metastatic potential.

Purpose: To evaluate the usefulness of combined treatment with both continuous administration of a hypoxic cytotoxin, tirapazamine (TPZ) and mild temperature hyperthermia (MTH) in boron neutron capture therapy (BNCT) in terms of local tumor response and lung metastatic potential, referring to the response of intratumor quiescent (Q) cells.Materials and methods: B16-BL6 melanoma tumor-bearing C57BL/6 mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. The tumors received reactor thermal neutron beam irradiation following the administration of a 10B-carrier (L-para-boronophenylalanine-10B (BPA) or sodium mercaptoundecahydrododecaborate-10B (BSH)) after single intraperitoneal injection of an acute hypoxia-releasing agent (nicotinamide), MTH (40 °C for 60 min), and 24-h continuous subcutaneous infusion of TPZ or combined treatment with both TPZ and MTH. Immediately after irradiation, cells from some tumors were isolated and incubated with a cytokinesis blocker. The responses of the Q and total (=P + Q) tumor cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumor-bearing mice, 17 days after irradiation, macroscopic lung metastases were enumerated.Results: BPA-BNCT increased the sensitivity of the total tumor cell population more than BSH-BNCT. However, the sensitivity of Q cells treated with BPA was lower than that of BSH-treated Q cells. With or without a 10B-carrier, combination with continuously administered TPZ with or without MTH enhanced the sensitivity of the both total and Q cells, especially Q cells. Even without irradiation, nicotinamide treatment decreased the number of lung metastases. With irradiation, BPA-BNCT, especially in combination with combined treatment with both TPZ and MTH as well as nicotinamide treatment, showed the potential to reduce the number more than BSH-BNCT.Conclusion: BSH-BNCT combined with TPZ with or without MTH improved local tumor control, while BPA-BNCT in combination with both TPZ and MTH as well as nicotinamide is thought to reduce the number of lung metastases. It was elucidated that control of the chronic hypoxia-rich Q cell population in the primary solid tumor has the potential to impact the control of local tumors as a whole and that control of the acute hypoxia-rich total tumor cell population in the primary solid tumor has the potential to impact the control of lung metastases.

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.

Usefulness of combined treatment with continuous administration of tirapazamine and mild temperature hyperthermia in γ-ray irradiation in terms of local tumour response and lung metastatic potential.

PURPOSE: To evaluate the usefulness of combined treatment with continuous administration of a hypoxic cytotoxin, tirapazamine (TPZ), and mild temperature hyperthermia (MTH) in γ-ray irradiation in terms of local tumour response and lung metastatic potential, referring to the response of intratumour quiescent (Q) cells. MATERIALS AND METHODS: B16-BL6 melanoma tumour-bearing C57BL/6 mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. The tumour-bearing mice then received γ-ray irradiation after a single intraperitoneal injection or 24 h continuous subcutaneous infusion of TPZ, either with or without MTH. Immediately after the irradiation, cells from some tumours were isolated and incubated with a cytokinesis blocker. The responses of the Q and total (= P + Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumour-bearing mice, 17 days after irradiation, macroscopic lung metastases were enumerated. RESULTS: Continuous administration elevated the sensitivity of both the total and Q cells, especially the total cells. MTH raised the sensitivity of Q cells more remarkably in both single and continuous administrations, probably because of more exposure to TPZ in intermediately hypoxic areas derived mainly from chronic hypoxia through MTH. With or without irradiation, TPZ, especially administered continuously and combined with MTH, decreased the number of lung metastases. CONCLUSION: The combination of continuous long-term administration of TPZ and MTH in γ-ray irradiation was thought to be promising because of its potential to enhance local tumour response and repress lung metastatic potential.

Influence of manipulating hypoxia in solid tumors on the radiation dose-rate effect in vivo, with reference to that in the quiescent cell population.

PURPOSE: The aim of this study was to clarify the effect of manipulating intratumor hypoxia on radiosensitivity under reduced dose-rate (RDR) irradiation. MATERIALS AND METHODS: Tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. They received gamma-rays or accelerated carbon-ion beams at high dose-rate (HDR) or RDR with or without tumor clamping to induce hypoxia. Some mice without clamping received nicotinamide, an acute hypoxia-releasing agent or misonidazole, a hypoxic cell radio-sensitizer before irradiation. The responses of quiescent (Q) and total (= P + Q) cells were assessed by the micronucleus frequency using immunofluorescence staining for BrdU. RESULTS: The clearer decrease in radiosensitivity in Q than total cells after RDR gamma-ray irradiation was suppressed with carbon-ion beams, especially with a higher linear energy transfer value. Repressing the decrease in the radiosensitivity under RDR irradiation through keeping tumors hypoxic during irradiation and enhancing the decrease in the radiosensitivity by nicotinamide were clearer with gamma-rays and in total cells than with carbon-ion beams and in Q cells, respectively. Inhibiting the decrease in the radiosensitivity by misonidazole was clearer with gamma-rays and in Q cells than with carbon-ion beams and in total cells, respectively. CONCLUSION: Manipulating hypoxia during RDR as well as HDR irradiation influences tumor radiosensitivity, especially with gamma-rays.

Inhibition of repair of radiation-induced damage by mild temperature hyperthermia, referring to the effect on quiescent cell populations.

PURPOSE: We evaluated the usefulness of mild temperature hyperthermia (MTH) as an inhibitor of the repair of radiation-induced damage in terms of the responses of the total [= proliferating (P) + quiescent (Q)] and Q cell populations in solid tumors in vivo. MATERIALS AND METHODS: SCC VII tumor-bearing mice received a continuous administration of 5-bromo-2'-deoxyuridine (BrdU) to label all P cells. They then underwent high-dose-rate (HDR) gamma-ray irradiation immediately followed by MTH or administration of caffeine or wortmannin; alternatively, they underwent reduced-dose rate gamma-ray irradiation simultaneously with MTH or administration of caffeine or wortmannin. Nine hours after the start of irradiation, the tumor cells were isolated and incubated with a cytokinesis blocker, and the micronucleus (MN) frequency in cells without BrdU labeling (= Q cells) was determined using immunofluorescence staining for BrdU. The MN frequency in the total tumor cell population was determined using tumors that were not pretreated with BrdU. RESULTS: In both the total and Q-cell populations, especially the latter, MTH efficiently suppressed the reduction in sensitivity caused by leaving an interval between HDR irradiation and the assay and decreasing the irradiation dose rate, as well as the combination with wortmannin administration. CONCLUSION: From the viewpoint of solid tumor control as a whole, including intratumor Q-cell control, MTH is useful for suppressing the repair of both potentially lethal and sublethal damage.

The usefulness of mild temperature hyperthermia combined with a newly developed hypoxia-oriented 10B conjugate compound, TX-2100, for boron neutron capture therapy.

PURPOSE: To evaluate the usefulness of a new 10B-compound (TX-2100) as a 10B-carrier in boron neutron capture therapy (BNCT), compared with the simultaneous use of its component drugs, sodium borocapate-10B (BSH) and 3-amino-2-quinoxalinecarbonitrile 1,4-dioxide (TX-402). Further, the usefulness of mild temperature hyperthermia (MTH, 40 degrees Celsius, 30 min) combined with TX-2100 was also examined compared with MTH combined with the concurrent administration with its component drugs. MATERIALS AND METHODS: TX-2100 is a hybrid compound that has both a hypoxic cytotoxin unit (TX-402) and a thermal neutron-sensitizing unit (BSH). TX-2100 or both TX-402 plus BSH in combination with MTH or not was administered to SCC VII tumour-bearing mice intra-peritoneally. Then, the 10B concentrations in the tumours and normal tissues were measured by gamma-ray spectrometry. Meanwhile, SCC VII tumour-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumours, then treated with TX-2100, TX-402 plus BSH or BSH only, in the same manner as in the biodistribution experiments, either with or without MTH. Right after thermal neutron irradiation during which intra-tumour 10B concentrations remained at similar levels, the tumours were excised, minced and trypsinized. The tumour cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker) and the micronucleus (MN) frequency in cells without BrdU labelling (=quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in the total (P + Q) tumour cell population was determined from the tumours that were not pre-treated with BrdU. The clonogenic cell survival was also determined in mice given no BrdU. RESULTS: 10B biodistribution analyses in tumours, brain, skin, muscles, blood and liver indicated that the administration of TX-2100 plus MTH is most favourable for concentrating a sufficient amount of 10B in tumours and maintaining a high enough 10B concentration during irradiation. In addition, MTH had a stronger sensitizing effect when combined with TX-2100 than with the concurrent administration of its components TX-402 and BSH on both the total and Q cell populations in solid tumours. CONCLUSION: MTH was very effective in combination with the newly-developed TX-2100. The sensitizing effect in combination with MTH should be examined when new 10B-carriers are designed.

Effects of mild temperature hyperthermia and p53 status on the size of hypoxic fractions in solid tumors, with reference to the effect in intratumor quiescent cell populations.

PURPOSE: To determine the effects of mild temperature hyperthermia (MTH) and p53 status of tumor cells on the size of hypoxic fractions (HFs) in solid tumors, with reference to the effect on intratumor quiescent (Q) cell populations. METHODS AND MATERIALS: Human head-and-neck squamous cell carcinoma cells transfected with mutant TP53 (SAS/mp53) or with neo vector as a control (SAS/neo) were inoculated subcutaneously into left hind legs of Balb/cA nude mice. Mice bearing the tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously to label all proliferating (P) cells in the tumors. The mice then received nicotinamide injection or carbogen gas (95% O(2), 5% CO(2)) inhalation combined with or without MTH. Nicotinamide prevents intermittent blood flow that could induce perfusion-limited acute hypoxia. Chronically hypoxic cells in regions beyond the limitation of oxygen diffusion in tumors are oxygenated by increasing the oxygen transport capacity of circulating blood with carbogen gas inhalation. After each treatment, the mice received a series of test doses of gamma-rays while alive or after tumor clamping to obtain HFs in the tumors. Immediately after irradiation, the tumors were excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with a cytokinesis blocker (cytochalasin-B) to inhibit cytoplasmic division while allowing nuclear division. Tumor cells not labeled with BrdU were detected with immunofluorescence staining of BrdU for P cells, and the micronucleus frequency in cells without BrdU labeling [ = Q cells] was determined. The micronucleus frequency in total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. RESULTS: SAS/mp53 tumors showed larger values for the size of not only the HF but also the diffusion-limited chronically HF than SAS/neo tumors. Q cell populations included a larger HF, particularly the chronically HF, than total cell populations in both tumors, especially in SAS/neo tumors. MTH could efficiently oxygenate the chronically HF, irrespective of p53 status. CONCLUSION: MTH is a useful combined treatment with a radioenhancement effect on intratumor Q cells, irrespective of the p53 status of tumor cells. The p53 status has the potential to affect microenvironmental conditions within solid tumors.

Local hyperthermia combined with external irradiation for regional recurrent breast carcinoma.

BACKGROUND: The purpose of this study was to evaluate the therapeutic effects of hyperthermia in combination with radiotherapy for locoregional recurrence of breast cancer, and to assess the factors related to subsequent local tumor control. METHODS: Between March 1981 and February 2001, 85 lesions in 73 patients were treated with local hyperthermia combined with external irradiation. Of 75 evaluable lesions, 41 were previously irradiated. Mean radiation dose to the previously unirradiated area was 59.5 +/- 6.8 Gy (range, 40-70 Gy), while a total dose of 43.0 +/- 12.4 Gy (range, 12-74.4 Gy) was administered to previously irradiated tumors. Hyperthermia was administered once or twice per week. The average number of hyperthermia sessions was 4.5 (2-9). RESULTS: Complete responses (CRs) were achieved in 56% (23/41) of previously irradiated and 47% (16/34) of unirradiated tumors. There was no significant difference in the CR rate between the two groups. Compared with the response of bulky/nodular tumors, diffuse/multiple small nodular tumors showed a higher CR rate at 4 weeks after treatment. However, at 6 months after treatment, they showed a significantly lower local control rate. CONCLUSIONS: The present findings suggested a significant benefit of local hyperthermia combined with radiotherapy in the treatment of locally recurrent breast cancer, especially for previously irradiated recurrence, by reducing the total irradiation dose. Diffuse/multiple small nodular tumors respond earlier than bulky/large nodular tumors; however, they tend to recur within the treatment field. The purpose of this study was to evaluate the therapeutic effects of hyperthermia in combination with radiotherapy for locoregional recurrence of breast cancer, and to assess the factors related to subsequent local tumor control.

Usefulness of combined treatment with mild temperature hyperthermia and/or tirapazamine in the treatment of solid tumors: its independence of p53 status.

Human head and neck squamous cell carcinoma cells transfected with mutant TP53 (SAS/mp53) or with neo vector as a control (SAS/neo) were inoculated subcutaneously into both hind legs of Balb/cA nude mice. Mice bearing the tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously to label all proliferating (P) cells in the tumors. The mice then received tirapazamine (TPZ) with or without mild temperature hyperthermia (40 degrees C, 60 min) (MTH), gamma-ray irradiation with or without MTH and/or TPZ, cisplatin (CDDP) with or without MTH and/or TPZ, or paclitaxel (TXL) with or without MTH and/or TPZ. After each treatment, the tumors were excised, minced and trypsinized. The tumor cell suspensions thus obtained were incubated with a cytokinesis blocker (cytochalasin-B), and the micronucleus (MN) frequency in cells without BrdU labeling (i.e., quiescent (Q) cells) was determined by using immunofluorescence staining for BrdU. Meanwhile, 6 h after gamma-ray irradiation or 24 h after other cytotoxic treatments, tumor cell suspensions obtained in the same manner were used for determining the frequency of apoptosis in Q cells. The MN frequency and apoptosis frequency in total (P+Q) tumor cells were determined from the tumors that were not pretreated with BrdU. On the whole, gamma-ray irradiation and CDDP injection induced a higher frequency of apoptosis and lower frequency of MN in SAS/neo cells than SAS/mp53 cells. There were no apparent differences in the induced frequency of apoptosis and MN between SAS/neo and SAS/mp53 cells after TPZ or TXL treatment. MTH sensitized cells to TPZ-inducing cytotoxicity more markedly in SAS/mp53 and Q cells than in SAS/neo cells and total cells, respectively. In gamma-ray irradiation and CDDP treatment, the enhancement in combination with MTH and/or TPZ was more remarkable in SAS/mp53 cells and Q cells than in SAS/neo and total tumor cells, respectively. Also in the case of TXL treatment, the combination with MTH and/or TPZ induced a slightly greater enhancement effect in SAS/mp53 cells and Q cells. In view of the difficulty in controlling mutated p53 status tumors and intratumor Q cells, combination treatment with MTH and/or TPZ as a cooperative modality in cancer therapy is considered to have potential for controlling solid tumors as a whole.

Potential of alpha-amino alcohol p-boronophenylalaninol as a boron carrier in boron neutron capture therapy, regarding its enantiomers.

PURPOSE: We evaluated the potential of a newly developed (10)B-containing alpha-amino alcohol of p-boronophenylalanine-(10)B (BPA), p-boronophenylalaninol (BPAol), as a boron carrier in boron neutron capture therapy. METHODS: C57BL mice bearing EL4 tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously via implanted mini-osmotic pumps to label all proliferating (P) cells. After oral administration of L-BPA or D-BPA, or intraperitoneal injection of L-BPAol or D-BPAol, the tumors were irradiated with reactor thermal neutron beams. Some of the tumors were heated at 40 degrees C for 30 min (mild temperature hyperthermia (MTH)) right before neutron exposure, and/or tirapazamine (TPZ) was intraperitoneally injected 30 min before irradiation. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling [ =quiescent (Q) cells] was determined using immunofluorescence staining for BrdU. Meanwhile, 6 h after irradiation, tumor cell suspensions obtained in the same manner were used for determining the apoptosis frequency in Q cells. The apoptosis and MN frequency in total (P+Q) tumor cells were determined from the tumors that were not pretreated with BrdU. RESULTS: Without TPZ or MTH, L- and D-BPAol increased both frequencies markedly, especially for total cells. Although not significantly larger, L-BPA and D-BPAol increased both frequencies slightly more than D-BPA and L-BPAol, respectively. Combination with both MTH and TPZ markedly reduced the sensitivity difference between total and Q cells. CONCLUSION: Both L- and D-BPAol have potential as a (10)B-carrier in neutron capture therapy, especially when combined with both MTH and TPZ.