RESUMEN
Clear cell sarcoma (CCS), a rare malignant tumor with a predilection for young adults, is of poor prognosis. Recently however, boron neutron capture therapy (BNCT) with the use of p-borono-L-phenylalanine (BPA) for malignant melanoma has provided good results. CCS also produces melanin; therefore, the uptake of BPA is the key to the application of BNCT to CCS. We describe, for the first time, the high accumulation of boron in CCS and the CCS tumor-bearing animal model generated for BNCT studies.
Asunto(s)
Compuestos de Boro/farmacocinética , Terapia por Captura de Neutrón de Boro , Fenilalanina/análogos & derivados , Sarcoma de Células Claras/metabolismo , Animales , Línea Celular Tumoral , Humanos , Técnicas In Vitro , Melanoma Experimental/metabolismo , Microscopía Electrónica , Fenilalanina/farmacocinéticaRESUMEN
Clear cell sarcoma (CCS) is a rare melanocytic malignant tumor with a poor prognosis. Our previous study demonstrated that in vitro cultured CCS cells have the ability to highly uptake l-BPA and thus boron neutron capture therapy could be a new option for CCS treatment. This paper proved that a remarkably high accumulation of (10)B (45-74 ppm) in tumor was obtained even in a CCS-bearing animal with a well-controlled biodistribution followed by intravenous administration of L-BPA-fructose complex (500 mg BPA/kg).
Asunto(s)
Compuestos de Boro/farmacocinética , Terapia por Captura de Neutrón de Boro , Fenilalanina/análogos & derivados , Sarcoma de Células Claras/radioterapia , Adolescente , Animales , Línea Celular Tumoral , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Fenilalanina/farmacocinética , Sarcoma de Células Claras/metabolismo , Distribución TisularRESUMEN
C57BL mice bearing EL4 tumors and 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. Three hours after oral administration of l-p-boronophenylalanine-(10)B (BPA), or 30 min after intraperitoneal injection of sodium borocaptate-(10)B (BSH) or l-p-boronophenylalaninol (BPA-ol), a newly developed (10)B-containing alpha-amino alcohol, the tumors were irradiated with thermal neutron beams. For the combination with mild temperature hyperthermia (MTH) and / or tirapazamine (TPZ), the tumors were heated at 40 degrees C for 30 min immediately before neutron exposure, and 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 MN and apoptosis frequency in total (P + Q) tumor cells were determined from tumors that were not pretreated with BrdU. Without TPZ or MTH, BPA-ol increased both frequencies most markedly, especially for total cells. However, as with BPA, the sensitivity difference between total and Q cells was much larger than with BSH. On combined treatment with both MTH and TPZ, this sensitivity difference was markedly reduced, similarly to when BPA was used. MTH increased the (10)B uptake of all (10)B-compounds into both tumor cells. BPA-ol has good potential as a (10)B-carrier in neutron capture therapy, especially when combined with both MTH and TPZ.
Asunto(s)
Boranos/farmacocinética , Terapia por Captura de Neutrón de Boro , Carcinoma de Células Escamosas/terapia , Linfoma/terapia , Fenilalanina/farmacocinética , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Boranos/administración & dosificación , Boranos/química , Boranos/efectos de la radiación , Bromodesoxiuridina/farmacología , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/patología , Terapia Combinada , Citocalasina B/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Técnica del Anticuerpo Fluorescente Indirecta , Miembro Posterior , Hipertermia Inducida , Inyecciones Intraperitoneales , Interfase , Linfoma/tratamiento farmacológico , Linfoma/patología , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Pruebas de Micronúcleos , Estructura Molecular , Neutrones , Fenilalanina/administración & dosificación , Fenilalanina/análogos & derivados , Fenilalanina/química , Fenilalanina/efectos de la radiación , Fármacos Sensibilizantes a Radiaciones/administración & dosificación , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Radiometría , Tirapazamina , Triazinas/administración & dosificación , Triazinas/uso terapéuticoRESUMEN
Takagaki, M., Ono, K., Masunaga, S-I., Kinashi, Y., Oda, Y., Miyatake, S-I., Hashimoto, N., Powell, W., Sood, A. and Spielvogel, B. F. Boronated Dipeptide Borotrimethylglycylphenylalanine as a Potential Boron Carrier in Boron Neutron Capture Therapy for Malignant Brain Tumors. Radiat. Res. 156, 118-122 (2001).A boronated dipeptide, borotrimethylglycylphenylalanine (BGPA), was synthesized as a possible boron carrier for boron neutron capture therapy (BNCT) for malignant brain tumors. In vitro, at equal concentrations of (10)B in the extracellular medium, BGPA had the same effect in BNCT as p-boronophenylalanine (BPA). Boron analysis was carried out using prompt gamma-ray spectrometry and track-etch autoradiography. The tumor:blood and tumor:normal brain (10)B concentration ratios were 8.9 +/- 2.1 and 3.0 +/- 1.2, respectively, in rats bearing intracranial C6 gliosarcomas using alpha-particle track autoradiography. The IC(50), i.e. the dose capable of inhibiting the growth of C6 gliosarcoma cells by 50% after 3 days of incubation, was 5.9 x 10(-3) M BGPA, which is similar to that of 6.4 x 10(-3) M for BPA. The amide bond of BGPA is free from enzymatic attack, since it is protected from hydrolysis by the presence of a boron atom at the alpha-carbon position of glycine. These results suggest promise for the use of this agent for BNCT of malignant brain tumors. Further preclinical studies of BGPA are warranted, since BGPA has advantages over both BPA and BSH.
Asunto(s)
Alanina/administración & dosificación , Compuestos de Boro/administración & dosificación , Terapia por Captura de Neutrón de Boro/métodos , Neoplasias Encefálicas/radioterapia , Fructosa/análogos & derivados , Gliosarcoma/radioterapia , Alanina/análogos & derivados , Animales , Autorradiografía , Compuestos de Boro/efectos de la radiación , Encéfalo/efectos de los fármacos , Encéfalo/patología , Encéfalo/efectos de la radiación , Neoplasias Encefálicas/química , Neoplasias Encefálicas/patología , División Celular/efectos de la radiación , Supervivencia Celular/efectos de la radiación , Modelos Animales de Enfermedad , Relación Dosis-Respuesta en la Radiación , Fructosa/administración & dosificación , Gliosarcoma/química , Gliosarcoma/patología , Concentración 50 Inhibidora , Masculino , Trasplante de Neoplasias , Neutrones , Ratas , Ratas Wistar , Células Tumorales CultivadasRESUMEN
Familial occurrence of nasal NK/T-cell lymphoma (NNKTCL) in pesticide users is presented. The proband (71 years old, male) and son (39 years old) were both diagnosed with NNKTCL within interval of 26 months. Laboratory data showed slight anemia, with no abnormal cells in peripheral blood. They and their wives were farmers and used large amounts of pesticides (fungicides and insecticides) in the hothouse. NNKTCL did not develop in the wives. Proband's father was diagnosed with malignant lymphoma of the neck and died of the disease. Genetic analyses of the peripheral blood leukocytes and tumor tissues did not show p53 and k-ras gene mutations and microsatellite instability. Metaphase cells from peripheral blood leukocytes bore specific marker chromosomes (father, 44XY,-14,-17,-18,-22,+2mar; son, 46XY,-17,+1mar). Environmental exposures to pesticides in conjunction with familial or genetic factors might increase the risk for NNKTCL.
Asunto(s)
Células Asesinas Naturales/patología , Linfoma de Células T/inducido químicamente , Neoplasias Nasales/inducido químicamente , Plaguicidas/efectos adversos , Adulto , Anciano , Aberraciones Cromosómicas , Análisis Citogenético , Exposición a Riesgos Ambientales/efectos adversos , Salud de la Familia , Predisposición Genética a la Enfermedad , Humanos , Linfoma de Células T/etiología , Linfoma de Células T/genética , Masculino , Neoplasias Nasales/etiología , Neoplasias Nasales/genética , LinajeRESUMEN
2,6,6-Trimethyl-2-azaspiro[4.4]nonane-1,3-dione (9), a spirosuccinimide moiety of asperparaline A (1), was synthesized by starting from 2,2-dimethylcyclopentanone (4) via trinitrile 6 in five steps in a moderate yield. This conversion establishes a model study for synthesis of the spirosuccinimide moiety of asperparaline A (1).
Asunto(s)
Alcaloides/química , Piperazinas , Compuestos de Espiro/síntesis química , Succinimidas/síntesis química , Modelos QuímicosRESUMEN
The kinetic behavior of chitinase A1 from Bacillus circulans WL-12 was investigated using the novel fluorogenic substrates, N-deacetylated 4-methylumbelliferyl chitobiosides [GlcN-GlcNAc-UMB (2), GlcNAc-GlcN-UMB (3), and (GlcN)(2)-UMB (4)], and the results were compared with those obtained using 4-methylumbelliferyl N, N'-diacetylchitobiose [(GlcNAc)(2)-UMB (1)] as the substrate. The chitinase did not release the UMB moiety from compound 4, but successfully released UMB from the other substrates. k(cat)/K(m) values determined from the releasing rate of the UMB moiety were: 145.3 for 1, 8.3 for 2, and 0.1 s(-1) M(-1) for 3. The lack of an N-acetyl group at subsite (-1) reduced the activity to a level 0.1% of that obtained with compound 1, while the absence of the N-acetyl group at subsite (-2) reduced the relative activity to 5.7%. These observations strongly support the theory that chitinase A1 catalysis occurs via a 'substrate-assisted' mechanism. Using these novel fluorogenic substrates, we were able to quantitatively evaluate the recognition specificity of subsite (-2) toward the N-acetyl group of the substrate sugar residue. The (-2) subsite of chitinase A1 was found to specifically recognize an N-acetylated sugar residue, but this specificity was not as strict as that found in subsite (-1).
Asunto(s)
Bacillus/enzimología , Quitinasas/metabolismo , Disacáridos/metabolismo , Acetilación , Disacáridos/química , Himecromona/análogos & derivados , Himecromona/química , Himecromona/metabolismo , Cinética , Especificidad por SustratoRESUMEN
R- and S-epimerization at the 3(1) position of bacteriochlorophyll (BChl) c and the formation of rod-like aggregates in chlorosomes of green sulfur bacteria were markedly affected in Chlorobium (Cb.) tepidum and Cb. limicola by cultivation under various light intensities (photon fluence rate). The stronger the light, the higher the ratio of the S-epimer to the R-epimer for each homolog of BChl c in the bacteria. S[P,E] BChl cF and S[I,E] BChl cF were found to be the major S-epimers in Cb. tepidum and Cb. limicola, respectively. R[P,E] BChl cF decreased markedly compared to R[E,E] BChl cF in Cb. tepidum, whereas no observable change in the ratio of R[P,E]/R[E,E] was detected for Cb. limicola. With increase in light intensity the Qy absorption maximum of the bacteria shifted to shorter wavelengths. In vitro spectroscopic studies of the aggregates showed a marked difference in the formation of aggregates from R- and S-epimers of BChl c; the S-epimers formed aggregates much more slowly than did the R-epimers. These results suggest that the ratio of the epimers of BChl c might significantly affect the aggregation of BChl in the chlorosome. We propose different roles for the R- and S-epimers in chlorosomes of Cb. limicola and Cb. tepidum.
Asunto(s)
Proteínas Bacterianas/metabolismo , Bacterioclorofilas , Chlorobi/efectos de la radiación , Proteínas Bacterianas/química , Relación Dosis-Respuesta en la Radiación , LuzRESUMEN
Partially and fully N-deacetylated 4-methylumberlliferyl chitobioside (1) derivatives, such as GlcN-GlcNAc-UMB (2), GlcNAc-GlcN-UMB (3), and (GlcN)2-UMB (4), were synthesized using chemo- and enzymatic procedure. Fluorescent aglycon was released from the chitobiosides 1, 2 and 3 by the action of chitinase. These UMB glycosides of heterochitobiose were versatile probes for the investigation of substrate binding chitinase from various sources.
Asunto(s)
Quitinasas/metabolismo , Disacáridos/síntesis química , Colorantes Fluorescentes/metabolismo , Bacillus/enzimología , Secuencia de Carbohidratos , Disacáridos/metabolismo , Especificidad por SustratoRESUMEN
Seven fungi, which are found to reduce ethyl 3-oxobutanoate in high yields, were tested for their reducing ability for ethyl 2-methyl 3-oxobutanoate. We obtained some interesting findings. In particular, Penicillium purpurogenum reduced ethyl 2-methyl 3-oxobutanoate to the corresponding alcohols with the diastereomer (anti/syn) ratio of 93/7 with the enantiomeric excess of anti-(2S,3S)- and syn-(2S,3R)- hydroxy esters of 90 and >99 ee%, respectively.
Asunto(s)
Butiratos/metabolismo , Hongos Mitospóricos/metabolismo , Aspergillus/metabolismo , Fusarium/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Espectroscopía de Resonancia Magnética , Penicillium/metabolismo , Trichoderma/metabolismoRESUMEN
4-Methylumbelliferyl beta-chitotrioside [(GlcN)(3)-UMB] was prepared from 4-methylumbelliferyl tri-N-acetyl-beta-chitotrioside [(GlcNAc)(3)-UMB] using chitin deacetylase from Colletotrichum lindemuthianum, and hydrolyzed by chitosanase from Streptomyces sp. N174. The enzymatic deacetylation of (GlcNAc)(3)-UMB was confirmed by (1)H-NMR spectroscopy and mass spectrometry. When the (GlcN)(3)-UMB obtained was incubated with chitosanase, the fluorescence intensity at 450 nm obtained by excitation at 360 nm was found to increase with proportion to the reaction time. The rate of increase in the fluorescence intensity was proportional to the enzyme concentration. This indicates that chitosanase hydrolyzes the glycosidic linkage between a GlcN residue and UMB moiety releasing the fluorescent UMB molecule. Since (GlcN)(3) itself cannot be hydrolyzed by the chitosanase, (GlcN)(3)-UMB is considered to be a useful low molecular weight substrate for the assay of chitosanase. The k(cat) and K(m) values obtained for the substrate (GlcN)(3)-UMB were determined to be 8.1 x 10(-5) s(-1) and 201 microM, respectively. From TLC analysis of the reaction products, the chitosanase was found to hydrolyze not only the linkages between a GlcN residue and UMB moiety, but also the linkages between GlcN residues. Nevertheless, the high sensitivity of the fluorescence detection of the UMB molecule would enable a more accurate determination of kinetic constants for chitosanases.
Asunto(s)
Glicósido Hidrolasas/metabolismo , Trisacáridos/metabolismo , Umbeliferonas/metabolismo , Amidohidrolasas/metabolismo , Secuencia de Carbohidratos , Catálisis , Hidrólisis , Cinética , Datos de Secuencia Molecular , Espectrometría de Fluorescencia , Streptomyces/enzimología , Trisacáridos/química , Umbeliferonas/químicaRESUMEN
Chlorella pyrenoidosa Chick reduced ethyl 2-methyl 3-oxobutanoate to the corresponding alcohols with the diastereomer (anti/syn) ratio of 53/47. The enantiomer excesses of anti-(2S, 3S)- and syn-(2S, 3R)-hydroxy esters were 89 and > 99ee% respectively. C. vulgaris and C. regularis afforded predominantly the syn-isomer, contrary to C. pyrenoidosa. The differences in the activity of reducing ethyl 2-methyl 3-oxobutanoate were observed among three strains of Chlorella. Addition of 2% metal salts slightly increased the chemical yield of the hydroxy ester.
Asunto(s)
Butiratos/química , Chlorella/química , Oxidación-Reducción , EstereoisomerismoRESUMEN
Both enantiomers of the C7-C12 segment (3 and 4) of antitumor antibiotics epothilones (1and 2) were synthesized from methyl (R)- and (S)-3-hydroxy-2-methylpropionate (5 and 6) in five steps in a fair yield.
RESUMEN
Circulation of a solution of 1 M D-fucose and 1 M D-glucose through a reaction system consisting of serial columns of immobilized recombinant beta-D-glucosidase of Bifidobacterium breve clb and activated charcoal gave two oligosaccharides. Structural analysis identified these oligosaccharides as D-fucosylglucose (6-O-beta-D-Fucopyranosyl-D-glucose) and gentiobiose (6-O-beta-D-Glucopyranosyl-D-glucose). The D-fucosylglucose obtained was well assimilated by many Bifidobacteria but not by the other intestinal bacteria tested.
Asunto(s)
Bifidobacterium/enzimología , Disacáridos/biosíntesis , Enzimas Inmovilizadas/metabolismo , beta-Glucosidasa/metabolismo , Animales , Bacterias/metabolismo , Bifidobacterium/metabolismo , Carbón Orgánico/química , Cromatografía en Capa Delgada , Disacáridos/química , Intestinos/microbiología , Espectroscopía de Resonancia Magnética , Espectrometría de Masa Bombardeada por Átomos VelocesRESUMEN
The efficient synthesis ofδ-hydroxy-ß,γ-dehydroα-amino acids (1) was achieved by the hybrid process, in which the Pd(II)-assisted rear-rangement ofß-acetoxyallylglycine ester (6) afforded the corresponding (E)-δ-acetoxyvinylglycine derivatives (7) in a moderate yield. The chemo- and stereo-selective hydrolysis of7 was accomplished by the use of microbial lipase (Amano PS) to afford the allylic alcohol (8), which was transformed into1 in two step sequence.
RESUMEN
The effects of sugar acids on the kinetics and the protein conformation of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) were examined to differentiate the ligand-binding modes of the catalytic sites. D-Glucarate, L-glucarate, and mucate inhibited the carboxylase activity of RuBisCO competitively with respect to ribulose 1,5-bisphosphate. Their inhibition constants were 2.5 to 8.5 mM. The sugar acids induced such a change of the protein conformation of activated RuBisCO as is detected with a hydrophobic fluorescence probe. However, the change was not concerned with hysteresis of the enzyme. The sugar acids bound to· the catalytic sites retarded the release of activator CO2 from the sites in the absence of CO2. These characteristics of the sugar acids were quite similar to those of 6-phosphogluconate, but not of fructose bisphosphate or 3-phosphoglycerate. It is proposed that sugar phosphates that bind to the catalytic sites of RuBisCO could be divided into two groups on the basis of the modes of the binding to the sites.
RESUMEN
A convenient synthetic method for the marine antibiotic (-)-malyngolide and its stereoisomers was accomplished from a chiral alpha-alkoxyketone (4), which was readily available as a chiron. Chiral quaternary carbon synthons (5a) and (5b) as the key intermediates were constructed by the chelation controlled addition of Grignard reagent to 4. The diastereomeric mixture of 5a and 5b was readily transformed into a separable mixture of lactones (7a) and (7b), each of which could be easily separated by silica-gel column chromatography. (-)-Malyngolide and its three stereoisomers were obtained in optically pure form without the need for optical resolution.