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S Kasai,
H Nagasawa,
M Yamashita,
M Masui,
H Kuwasaka,
T Oshodani,
Y Uto,
T Inomata,
S Oka,
S Inayama,
H Hori
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ABSTRACT: We designed, based on the molecular orbital (MO) calculation, synthesized, and evaluated the biological activities of the new antimetastatic hypoxic cell radiosensitizer, 2-nitroimidazole-acetamide, TX-1877, and its analogues. Each analogue has an electron-affinic imidazole group, an acetamide group and a certain hydrophilic group to control its biological effect, toxicity, and pharmacokinetics. In in vitro radiosensitization assay, most TX-1877 analogues, which have an electron affinity (EA) of more than 0.9 eV and partition coefficient (P) of more than 0.021, showed satisfactory enhancement ratios (ER > 1.60) at doses of I mM. On the other hand, imidazole analogues, such as TX-1908 (EA = 0.67 eV), TX-1910 (EA = -0.34 eV) and TX-1931 (EA = -0.37 eV), which have low electron affinities, had an ER of 1.31 or less. TX-1877 and KIN-806 effectively inhibited tumor regrowth when administered with irradiation in vivo at a dose of 0.4 mg/g. Tumor lung metastasis was inhibited by treatment with either TX-1877 or KIN-806 without irradiation at a dose of 0.4 mg/g. TX-1877 reduced markedly the mean number of metastatic lung nodules in comparison with KIN-806. Moreover, TX-1877 and KIN-806 enhanced macrophage and helper T lymphocyte infiltration for 3 weeks after drug treatment. TX-1877 shows a high EA value and has the C2 of HOMO localizing on N-methylamide and the C2 of LUMO localizing on 2-nitroimidazole group. The MO data might be useful for designing a bifunctional hypoxic cell radiosensitizer. TX-1877 and its analogues are potential antimetastatic hypoxic cell radiosensitizers, which would improve the efficiency of radiotherapy and quality of life in cancer treatment.
Bioorganic & Medicinal Chemistry 03/2001; 9(2):453-64. · 2.92 Impact Factor
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ABSTRACT: C3H/He mice bearing SCC VII tumours received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. The mice then received gamma-ray irradiation, or administration of tirapazamine (TPZ), cisplatin or bleomycin. At various time points after each treatment, tumour-bearing mice were irradiated with a series of test doses of gamma-rays, while alive or after being killed, to obtain hypoxic fractions (HFs) in the tumours. Immediately after gamma-ray test irradiation, the tumours were excised, minced and trypsinized. Tumour cell suspensions obtained were incubated with cytochalasin-B, a cytokinesis blocker, and the micronucleus (MN) frequency in cells without BrdU labelling (i.e. quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. MN frequency in the total (P + Q) tumour cells was determined from the tumours that were not pre-treated with BrdU. MN frequency of BrdU-unlabelled cells was then used to calculate the surviving fraction of the unlabelled cells from the regression line for the relationship between the MN frequency and the surviving fraction of total tumour cells. TPZ and cisplatin reduced the HF after treatment, especially in Q cells, and this tendency was particularly marked with TPZ. In contrast, bleomycin increased the HF after treatment. Both reoxygenation following gamma-ray irradiation or bleomycin treatment and a subsequent return to pre-treatment levels of HF following TPZ or cisplatin treatment (rehypoxiation) occurred more rapidly in total (P + Q) cells than in Q cells. Based on our previous report that total (P + Q) and Q cells within this tumour have large acutely and chronically HFs, respectively, we conclude that acute hypoxic cells play a major role in reoxygenation and rehypoxiation in SCC VII tumours.
British Journal of Radiology 10/2000; 73(873):978-86. · 1.31 Impact Factor
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ABSTRACT: Mice bearing solid tumors received 10 intraperitoneal administrations of 5-bromo-2'-deoxyuridine (BrdU) to label the proliferating (P) tumor cells. Then, as a priming treatment, tirapazamine (TPZ) was intraperitoneally administered. Further, 0 through 48 h later, the tumor-bearing mice received TPZ again at various doses. The tumor cells were isolated and incubated with a cytokinesis blocker. The micronucleus (MN) frequencies in cells with and without BrdU labeling, which were regarded as P and quiescent (Q) cells at the priming treatment, respectively, were determined using immunofluorescence staining for BrdU. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. In addition, P cell ratios in the tumors at the second treatment were determined using immunofluorescence staining for P cell nuclear antigen. In each cell fraction, the longer the interval between the two treatments, the higher was the sensitivity to TPZ, except 1 h after the priming treatment. More than 24 h later, total and P cells, especially P cells, showed significantly higher sensitivity to TPZ than in the case of a single TPZ treatment. The longer the period between the two TPZ treatments, the lower was the P cell ratio at the second treatment. These findings were thought to indicate that the use of TPZ in the treatment of solid tumors causes a shift from the P to the Q state in vivo.
Japanese journal of cancer research: Gann 08/2000; 91(7):731-6.
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S Masunaga,
K Ono,
Y Nishimura,
S Kanamori,
T Saga,
M Suzuki,
Y Kinashi,
M Takagaki, S Kasai,
H Nagasawa,
Y Uto,
H Hori
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ABSTRACT: To evaluate the efficacy of the use of tirapazamine (TPZ), especially combined with mild hyperthermia (40 degrees C, 60 min), in the treatment of solid tumors following an anti-angiogenic treatment with TNP-470. In addition, we assessed the effect of TPZ and/or mild hyperthermia (MHT) combined with conventional radiotherapy or chemotherapy on TNP-470 treated tumors.
C3H/He mice bearing SCC VII tumors subcutaneously received TNP-470 at two doses of 100 mg/kg after tumor cell inoculation. At the same time, the tumor-bearing mice received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. The mice then received TPZ administration combined with or without MHT, gamma-ray irradiation combined with or without TPZ and/or MHT, or cisplatin injection with or without TPZ and/or MHT. Another group of mice received a series of test doses of gamma-rays while alive or after being killed to obtain hypoxic fractions (HFs) in the tumors at various time points after the above-mentioned cytotoxic treatment point. After each treatment, the tumors were 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 (or quiescent [Q] cells) was determined using immunofluorescence staining for BrdU. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. For the measurement of the HFs, the MN frequency of BrdU-unlabeled cells was then used to calculate the surviving fraction of the unlabeled cells from the regression line for the relationship between the MN frequency and the surviving fraction of total tumor cells.
TPZ administration combined with TNP-470 treatment and MHT increased the MN frequency more markedly than treatment with TPZ alone, and this tendency was more remarkable in Q cells than total cells. In both total and Q cells, combined treatment with TPZ and MHT produced significant increases in MN frequencies whether gamma-rays were delivered to TNP-470 treated tumors or cisplatin was injected into the TNP-470 administered mice. Although not significantly, the HFs of total and Q cell populations within solid tumors increased after TNP-470 treatment.
Combined treatment with TPZ and MHT, whether other cytotoxic treatments such as gamma-ray irradiation or chemotherapy using cisplatin were combined or not, was useful for sensitizing tumor cells in vivo including Q cells even after TNP-470 treatment.
International Journal of Radiation OncologyBiologyPhysics 07/2000; 47(3):799-807. · 4.11 Impact Factor
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ABSTRACT: C3H / He mice bearing SCC VII tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. The mice then received one of six different DNA-damaging agents with or without mild temperature hyperthermia (40 degrees C, 30 min, MTH). These agents were adriamycin (ADM), mitomycin C (MMC), cyclophosphamide (CPA), bleomycin (BLM), cisplatin (CDDP), and tirapazamine (TPZ). After the drug treatment, the tumor-bearing mice were irradiated with a series of doses of gamma-rays. Immediately after irradiation, the tumors were 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. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that had not been pretreated with BrdU. MTH significantly increased the MN frequency of total cells in tumors irradiated with gamma-rays combined with CPA, BLM, CDDP or TPZ, and that of Q cells in tumors irradiated with gamma-rays combined with BLM or TPZ. The sensitivity difference in the MN frequency between total and Q tumor cells was significantly decreased by the combination with TPZ. TPZ combined with radiotherapy and TPZ combined with thermo-radiotherapy at mild temperatures appear to be promising modalities for sensitizing tumor cells in vivo, including Q tumor cells.
Japanese journal of cancer research: Gann 06/2000; 91(5):566-72.
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ABSTRACT: 2-Nitroimidazole acetamide TX-1877 and its derivatives (TX-1877 analogs) were designed, synthesized, and evaluated by their in vitro and in vivo radiosensitization, tumor growth control, suppression of lung metastasis, and immunopotentiation, as biological response modifier (BRM)-functional hypoxic cell radiosensitizers.
TX-1877 analogs were designed and synthesized in our laboratory. In vitro radiosensitizing ability was estimated using EMT6/KU cells under hypoxic conditions. In vivo radiosensitization, antimetastasis, and immunopotentiation were evaluated using female C3H/He mice bearing the SCCVII tumor. Days (15 or 10) after the inoculation of 10(5) SCCVII tumor cells into the hinder thigh, a drug (0.4 mg/g) was administered i.p. and local irradiation of 30 Gy was given at 30 min after its administration. Tumor growth was observed for 20 days and mice were euthanized to count the number of metastatic nodules on the surface of the lungs. Tumor tissues were extirpated and stained by the ABC method at 1, 2, and 3 weeks after treatment for immunological evaluation.
Novel types of bifunctional radiosensitizers, TX-1877 and its analogs possessing BRM-functions (i.e., antimetastatic and immunopotentiation effects) were developed. In vitro radiosensitizing abilities of TX-1877 and its analogs, with their partition coefficient values of more than 0.050, were comparable to misonidazole (MISO) at their doses of 1 mM. Tumor regrowth was suppressed evidently 20 days after the treatment in the irradiated group with TX-1877 (TX-1877 plus R) and with KIN-806 (KIN-806 plus R). The former group reduced markedly the mean number of metastatic lung nodules regardless of radiation therapy. TX-1877 and KIN-806 plus R induced helper T lymphocytes. The TX-1877, TX-1877 plus R, KIN-806, and KIN-806 plus R enhanced macrophage infiltration for 3 weeks after treatment.
TX-1877 is an excellent BRM-functional hypoxic cell radiosensitizer, expected to be useful for clinical use.
International Journal of Radiation OncologyBiologyPhysics 12/1998; 42(4):799-802. · 4.11 Impact Factor
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ABSTRACT: We designed, synthesized, and evaluated haloacetylcarbamoyl-2-nitroimidazoles, including chloro (KIN-1800, TX-1835, and TX-1836) and bromo derivatives (TX-1844, TX-1845, and TX-1846), as potential hypoxic cell radiosensitizers with antiangiogenic activities. To establish biological function owing to the haloacetylcarbamoyl group in the side-chain, we compared their in vitro radiosensitizing activities with those of their parent 2-nitroimidazoles without haloacetylcarbamoyl groups: misonidazole (MISO), TX-1831, and TX-1832, respectively. Both tert-butoxy substituted derivatives. TX-1835 and TX-1845, were more potent radiosensitizers than TX-1831. The p-tert-butylphenoxy-substituted derivatives, TX-1836 and TX-1846, and the methoxysubstituted derivatives, KIN-1800 and TX-1844, were stronger radiosensitizers than TX-1832 and MISO. We examined the anti-angiogenic activities of these 2-nitroimidazole derivatives containing haloacetylcarbamoyl group by the rat lung endothelial (RLE) cell proliferation assay and chick embryo chorioallantoic membrane (chick CAM) angiogenesis assay and showed that haloacetylcarbamoyl-2-nitroimidazoles were more potent angiogenic inhibitors than the corresponding desacetylcarbamoyl-2-nitroimidazoles. The in vivo chick CAM angiogenesis assay showed that the strong bromoacetylcarbamoyl-2-nitroimidazole radiosensitizers, such as TX-1845 and TX-1846, were the strongest angiogenic inhibitors among them. We concluded that the bromoacetylcarbamoyl-2-nitroimidazole radiosensitizers, such as TX-1845 and TX-1846, are promising as anti-angiogenic hypoxic cell radiosensitizers.
Bioorganic & Medicinal Chemistry 04/1997; 5(3):591-9. · 2.92 Impact Factor
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ABSTRACT: New N-thiadiazolylanilines were designed and synthesized to develop mitochondrial cytotoxins superior to SF 6847. The mitochondrial cytotoxin N-thiadiazolylanilines, TX-108 and TX-109, inhibited EMT6/KU mammary sarcoma cell growth at a low micromolar concentration. Their inhibitory activities were parallel to their mitochondrial cytotoxicity, such as uncoupling oxidative phosphorylation and inhibiting ATP synthesis. This report also supports the notion that the inhibition of tumor cell growth of inhibitor of protein tyrosine kinase AG17, which is identical to SF 6847, may be due to its mitochondrial cytotoxicity.
Bioorganic & Medicinal Chemistry 03/1996; 4(2):247-53. · 2.92 Impact Factor
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ABSTRACT: C3H/He and Balb/c mice bearing SCC VII or EMT6/KU tumours received continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days to label all proliferating (P) cells. The tumours were locally heated at 40 degrees C for 60 min and/or the tumour-bearing mice received intraperitoneal injection of nicotinamide, and then tirapazamine (TPZ) was injected intraperitoneally. Sixty minutes after TPZ injection, the tumours were excised, minced and trypsinized. The tumour cell suspensions 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. The MN frequency in total (P+Q) tumour cells was determined from the tumours that were not pretreated with BrdU. The cytotoxicity of TPZ was evaluated in terms of the frequency of induced micronuclei in binuclear tumour cells (= MN frequency). In both tumour systems, the MN frequencies of Q cells were greater than those of total tumour cell populations. Mild heat treatment elevated the MN frequency in total and Q cells in both tumour systems, but the effect was more marked in Q cells. In total cells, mild heat treatment increased the MN frequency in EMT6/KU tumour cells more markedly than in SCC VII tumour cells. In contrast, in both tumour systems, nicotinamide decreased the MN frequency in both cell populations, with a greater influence on the total cells. The combination of TPZ and mild heat treatment may be useful for sensitizing tumour cells in vivo, including Q cells.
International Journal of Hyperthermia 15(1):7-16. · 1.92 Impact Factor
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ABSTRACT: We examined the enhanced chemosensitivity of quiescent (Q) cells in solid tumors to cis-diamminedichloroplatinum (II) (cisplatin) by combined treatment with tirapazamine (TPZ) and mild heating. C3H/He and Balb/c mice bearing SCC VII and EMT6/KU tumors, respectively, received continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days using implanted mini-osmotic pumps to label all proliferating (P) cells. TPZ was administered intraperitoneally 2 h before cisplatin injection and/or tumors were locally heated at 40 degrees C for 60 min immediately after cisplatin injection. Sixty minutes after cisplatin injection, the tumors were excised, minced and trypsinized. The tumor cell suspensions were incubated with cytochalasin-B (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 total (P+Q) tumor cells was determined from the tumors that were not pretreated with BrdU. The sensitivity to cisplatin was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). Other groups of tumor-bearing C3H/He and Balb/c mice not given BrdU were injected with 195mPt-radiolabeled cisplatin. In both tumor systems, the MN frequency in Q cells was lower than that in the total cells. TPZ and mild heat treatment elevated the MN frequency in total and Q cells in both tumor systems, and to a higher extent in Q cells. The combination of TPZ and mild heat treatment increased the MN frequency more markedly than treatment with either TPZ or mild heating alone. In total tumor cells, TPZ and mild heat treatment increased the MN frequency in EMT6/KU tumor cells more markedly than in SCC VII tumor cells. 195mPt-labeled cisplatin uptake into total tumor cells was increased by mild heat treatment but not by TPZ. The cisplatin-sensitivity of Q cells was lower than that of total cells in both tumor systems. TPZ was thought to sensitize Q cells by killing the hypoxic cells without influencing tumor blood flow, and mild hyperthermia appeared to sensitize Q cells by distributing more cisplatin with an increase in blood flow in solid tumors.
Radiation Medicine 16(6):441-8.
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ABSTRACT: After continuous labeling of proliferating (P) cells with 5-bromo-2'-deoxyuridine (BrdU) for 5 days, SCC VII tumor-bearing mice received various kinds of DNA-damaging treatments: gamma-ray irradiation, tirapazamine (TPZ, hypoxia-specific cytotoxin) administration, or cisplatin injection. From 0.5 to 72 hr after treatment, tumors were excised, minced, and trypsinized. Single tumor cell suspensions were incubated for 48 hr with a cytokinesis-blocker, cytochalasin-B. Then, the micronucleus (MN) frequency for BrdU-unlabeled cells, quiescent (Q) cells at treatment, was determined using immunofluorescence staining for BrdU. The MN frequency for total (P+Q) cells was obtained from tumors that were not pretreated with BrdU labeling. The sensitivity to each DNA-damaging treatment was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). Treatment with gamma-rays or cisplatin resulted in a larger MN frequency in total cells than in Q cells. In contrast, TPZ treatment produced a smaller MN frequency in total cells than in Q cells. Regardless of the treatment used, Q cells showed greater repair capacities than total cells. However, TPZ caused much smaller repair capacity in both total and Q cells, compared with gamma-rays or cisplatin. Gamma-rays and cisplatin produced similar repair patterns. Differences in sensitivity between total and Q cells and repair patterns of the two cell populations were thought to depend on differences between the two cell populations in the toxicity of the DNA-damaging treatment and distribution pattern of the anticancer agent.
Radiation Medicine 17(4):259-64.
