RESUMEN
Angiotensin converting enzyme 2 (ACE2), a newly discovered member of the renin-angiotensin system (RAS), is a potential therapeutic target for the control of cardiovascular disease owing to its key role in the formation of vasoprotective peptides from angiotensin II. The aim of the present study was to evaluate whether overexpression of ACE2 could protect the heart from angiotensin II-induced hypertrophy and fibrosis. Lentiviral vector encoding mouse ACE2 (lenti-mACE2) or GFP was injected intracardially in 5-day-old Sprague-Dawley rats. This resulted in expression of mACE2 in cardiac tissue for the duration of the study. Infusion of 200 ng kg-1 min-1 angiotensin II for 4 weeks resulted in an 80 mmHg increase in systolic blood pressure, a significant increase in the heart weight to body weight ratio (HW:BW), and marked myocardial fibrosis in control rats. Transduction with lenti-mACE2 resulted in significant attenuation of the increased HW:BW and myocardial fibrosis induced by angiotensin II infusion. These observations demonstrate that ACE2 overexpression results in protective effects on angiotensin II-induced cardiac hypertrophy and fibrosis.
Asunto(s)
Angiotensina II/farmacología , Carboxipeptidasas/administración & dosificación , Cardiomiopatía Hipertrófica/prevención & control , Fibrosis Endomiocárdica/prevención & control , Enzima Convertidora de Angiotensina 2 , Animales , Animales Recién Nacidos , Presión Sanguínea/efectos de los fármacos , Peso Corporal , Carboxipeptidasas/biosíntesis , Carboxipeptidasas/genética , Expresión Génica , Vectores Genéticos , Corazón/efectos de los fármacos , Lentivirus/genética , Ratones , Miocardio/enzimología , Miocardio/patología , Tamaño de los Órganos/efectos de los fármacos , Peptidil-Dipeptidasa A , Ratas , Ratas Sprague-Dawley , Transducción GenéticaRESUMEN
Hypodermal injection of Toughmac-E, a digestive mixture composed of nine digestive components, or Molsin induced perturbation of the wing color pattern in 0- to 2-day-old pupae of Papilio xuthus, but had no effect on prepupae or 3- to 4-day-old pupae. The effective component in Toughmac-E was identified as Molsin, an acid carboxypeptidase of Aspergillus saitoi which specifically liberates tyrosine and phenylalanine from the C-terminal residues of proteins. The pattern perturbation occurred in either side of the fore- and hindwings of both sexes. When this enzyme was administered, stronger melanization than in the normal wings was found in the whole wings of most butterflies, but in other butterflies, the yellow region was enlarged. These findings suggest that the pattern perturbation was caused by changes in the levels of melanin and papiliochromes in scales. Melanin is a black pigment and papiliochromes are yellow pigments; their common precursor is dopamine. The normal pattern is formed by a predetermined balance of melanin and papiliochromes, whereas the deposit of an excess amount of tyrosine and/or phenylalanine disturbs this balance and results in perturbation of the color pattern. Administration of L-dopa or dopamine had no effect on the wing pattern. When the activity of an endogenous acid carboxypeptidase similar to Molsin appears in the early pupa, the summed activities of the endogenous and exogenous acid carboxypeptidases must induce a pattern perturbation. The relations between the endogenous acid carboxypeptidase and its probable substrate, the reserve protein, and the physiological roles of these relations in the regulation, utilization and excretion of amino acids are discussed.
Asunto(s)
Mariposas Diurnas/fisiología , Carboxipeptidasas/farmacología , Color , Pigmentos Biológicos/metabolismo , Alas de Animales/fisiología , Animales , Mariposas Diurnas/efectos de los fármacos , Mariposas Diurnas/crecimiento & desarrollo , Carboxipeptidasas/administración & dosificación , Dopamina/farmacología , Femenino , Levodopa/farmacología , Masculino , Pupa/efectos de los fármacos , Pupa/metabolismo , Alas de Animales/efectos de los fármacos , Alas de Animales/crecimiento & desarrolloRESUMEN
OBJECTIVE: To determine the ultrasonographic appearance and detectability of edema induced by SC injection of mild silver protein suspension in the mammary gland attachments of dairy cows. DESIGN: Prospective study. ANIMALS: 6 lactating cows. PROCEDURE: In each cow, the number of quarters that received injections was randomly assigned. A mild silver protein susoension was injected SC into cranial and caudal mammary gland attachment sites. The number of injections and volume injected were determined on the basis of the appearance of the mammary gland and the desired subjective visual effect. Seventeen sites were chosen for injection and 7 sites did not receive injections. Ultrasonographic images were obtained 1 day prior and 6 days after injections were started. Cows received injections 1, 3, and 5 days after initial sonography. The sonographer was unaware of which sites received injections. RESULTS: Ultrasonography revealed alternating hypoechoic and hyperechoic bands at injection sites. Certain injections caused the intimal surface of the subcutaneous abdominal vein to develop a corrugated appearance. All injection sites were correctly identified ultrasonographically (100% sensitivity, 100% specificity) with a positive and negative predictive value of 1.0. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that mild silver protein suspension injected SC to enhance the appearance of the mammary glands of dairy cows can be readily detected by ultrasonography. Detection of injection sites should be made on the basis of the distribution and ultrasonographic appearance of edema.
Asunto(s)
Carboxipeptidasas/administración & dosificación , Enfermedades de los Bovinos/diagnóstico por imagen , Edema/veterinaria , Glándulas Mamarias Animales/diagnóstico por imagen , Glicoproteínas de Membrana/administración & dosificación , Proteínas , Ultrasonografía Mamaria/veterinaria , Animales , Carboxipeptidasas/efectos adversos , Bovinos , Enfermedades de los Bovinos/inducido químicamente , Edema/inducido químicamente , Edema/diagnóstico por imagen , Ética , Femenino , Inyecciones Subcutáneas/veterinaria , Glándulas Mamarias Animales/patología , Glicoproteínas de Membrana/efectos adversos , Valor Predictivo de las Pruebas , Estudios Prospectivos , Distribución Aleatoria , Sensibilidad y EspecificidadRESUMEN
Protective protein/cathepsin A (PPCA), a lysosomal carboxypeptidase, is deficient in the neurodegenerative lysosomal disorder galactosialidosis (GS). PPCA(-/-) mice display a disease course similar to that of severe human GS, resulting in nephropathy, ataxia, and premature death. Bone marrow transplantation (BMT) in mutant animals using transgenic BM overexpressing the corrective enzyme in either erythroid cells or monocytes/macrophages has proven effective for the improvement of the phenotype, and encouraged the use of genetically modified BM cells for ex vivo gene therapy of GS. Here, we established stable donor hematopoiesis in PPCA(-/-) mice that received hematopoietic progenitors transduced with a murine stem cell virus (MSCV)-based, bicistronic retroviral vector overexpressing PPCA and the green fluorescent protein (GFP) marker. We observed complete correction of the disease phenotype in the systemic organs up to 10 months after transplantation. PPCA(+) BM-derived cells were detected in all tissues, with the highest expression in liver, spleen, BM, thymus, and lung. In addition, a lysosomal immunostaining was seen in nonhematopoietic cells, indicating efficient uptake of the corrective protein by these cells and cross-correction. Expression in the brain occurred throughout the parenchyma but was mainly localized on perivascular areas. However, PPCA expression in the central nervous system was apparently sufficient to delay the onset of Purkinje cell degeneration and to correct the ataxia. The long-term expression and internalization of the PPCA by cells of systemic organs and the clear improvement of the neurologic phenotype support the use of this approach for the treatment of GS in humans. (Blood. 2002;99:3169-3178)
Asunto(s)
Células Madre Hematopoyéticas/metabolismo , Enfermedades por Almacenamiento Lisosomal/terapia , Mucolipidosis/terapia , Animales , Ataxia/etiología , Ataxia/terapia , Células de la Médula Ósea/citología , Carboxipeptidasas/administración & dosificación , Carboxipeptidasas/genética , Carboxipeptidasas/farmacocinética , Catepsina A , Enfermedades del Sistema Nervioso Central/etiología , Enfermedades del Sistema Nervioso Central/terapia , Terapia Genética/métodos , Proteínas Fluorescentes Verdes , Trasplante de Células Madre Hematopoyéticas , Enfermedades Renales/etiología , Enfermedades Renales/terapia , Proteínas Luminiscentes/genética , Ratones , Ratones Noqueados , Mucolipidosis/complicaciones , Mucolipidosis/patología , Neuraminidasa/deficiencia , Especificidad de Órganos , Distribución Tisular , Resultado del Tratamiento , beta-Galactosidasa/deficienciaRESUMEN
Over the last decade several attempts have been made to generate an active drug from an inactive precursor, by the action of an enzyme present predominantly at the tumour site. The aim was to develop a new, less cytotoxic strategy for the treatment of cancer, by exploiting properties distinguishing neoplastic and normal cells. In fact, monoclonal antibodies were used to carry enzymes at the tumour sites, in a two-step approach, known as Antibody Directed Enzyme Prodrug Therapy (ADEPT). We reviewed the experimental and clinical considerations of this strategy and we presented its problems and limitations. We concluded that ADEPT holds the potential of an effective and relatively non-toxic treatment of cancer and it is expected that the research which is in progress will make ADEPT an important element of the anticancer armament.
Asunto(s)
Anticuerpos Monoclonales/administración & dosificación , Enzimas/administración & dosificación , Neoplasias/terapia , Profármacos/administración & dosificación , Fosfatasa Alcalina/administración & dosificación , Animales , Carboxipeptidasas/administración & dosificación , Humanos , Nitrorreductasas/administración & dosificación , Profármacos/metabolismo , beta-Glucosidasa/administración & dosificaciónRESUMEN
BACKGROUND: A phase II trial was conducted to assess the efficacy of infusions of dendritic cells (DC) and two HLA-A2-specific PSMA peptides (PSM-P1 and -P2). This report describes thirty three subjects with hormone-refractory metastatic prostate cancer without prior vaccine therapy history who were evaluated and reported as a group. METHODS: All subjects received six infusions of DC pulsed with PSM-P1 and -P2 at six week intervals. Clinical monitoring was conducted pre-, during, and post- phase II study. Data collected include: complete blood count, bone and total alkaline phosphatase, prostate markers, physical examination, performance status, bone scan, ProstaScint scan, chest x-ray, as well as assays to monitor cellular immune responses. RESULTS: Six partial and two complete responders were identified in the phase II study based on NPCP criteria, plus 50% reduction of prostate-specific antigen (PSA), or resolution in previously measurable lesions on ProstaScint scan. CONCLUSIONS: Over 30% of study participants in this group showed a positive response at the conclusion of the trial. This study suggested that DC-based cancer vaccines may provide an alternative therapy for prostate cancer patients whose disease no longer responds to hormone therapy.
Asunto(s)
Antígenos de Superficie , Vacunas contra el Cáncer/uso terapéutico , Carboxipeptidasas/uso terapéutico , Antígeno HLA-A2/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Vacunas Sintéticas/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Antígenos de Neoplasias/administración & dosificación , Antígenos de Neoplasias/uso terapéutico , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/secundario , Vacunas contra el Cáncer/administración & dosificación , Carboxipeptidasas/administración & dosificación , Células Dendríticas , Glutamato Carboxipeptidasa II , Antígeno HLA-A2/administración & dosificación , Hormonas/uso terapéutico , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Cintigrafía , Resultado del Tratamiento , Vacunas Sintéticas/administración & dosificaciónRESUMEN
Recent in vitro studies have shown that fibrinolytic activity may be attenuated by a thrombin-activatable fibrinolysis inhibitor (TAFI), which is activated by thrombin, generated via the intrinsic pathway of coagulation in a factor XI-dependent way. Thus factor XI may play a role in the regulation of endogenous fibrinolysis. The aim of this study was to investigate the effect of in vivo inhibition of factor XI and TAFI in an experimental thrombosis model in rabbits. Incorporation of anti-factor XI antibodies in jugular vein thrombi resulted in an almost twofold increase in endogenous thrombolysis compared with a control antibody. A similar effect was observed when the anti-factor XI antibody was administered systemically. Inhibition of TAFI activity also resulted in a twofold increase in clot lysis whereas inhibition of both factor XI and TAFI activity had no additional effect. Thus, we provide the first in vivo evidence for enhanced thrombolysis through inhibition of clotting factor XI, demonstrating a novel role for the intrinsic pathway of coagulation. Furthermore we demonstrate that inhibition of TAFI had a similar effect on thrombolysis. We postulate that inhibition of factor XI activity enhances thrombolysis because of diminished indirect activation of TAFI.
Asunto(s)
Factor XI/fisiología , Fibrinólisis/fisiología , Venas Yugulares/fisiopatología , Trombosis/fisiopatología , Animales , Anticuerpos/administración & dosificación , Carboxipeptidasa B2 , Carboxipeptidasas/administración & dosificación , Carboxipeptidasas/fisiología , Pruebas de Neutralización , Proteínas de Plantas/administración & dosificación , Conejos , Solanum tuberosumRESUMEN
Antibody-directed enzyme prodrug therapy (ADEPT) has the potential of greatly enhancing antitumor selectivity of cancer therapy by synthesizing chemotherapeutic agents selectively at tumor sites. This therapy is based upon targeting a prodrug-activating enzyme to a tumor by attaching the enzyme to a tumor-selective antibody and dosing the enzyme-antibody conjugate systemically. After the enzyme-antibody conjugate is localized to the tumor, the prodrug is then also dosed systemically, and the previously targeted enzyme converts it to the active drug selectively at the tumor. Unfortunately, most enzymes capable of this specific, tumor site generation of drugs are foreign to the human body and as such are expected to raise an immune response when injected, which will limit their repeated administration. We reasoned that with the power of crystallography, molecular modeling and site-directed mutagenesis, this problem could be addressed through the development of a human enzyme that is capable of catalyzing a reaction that is otherwise not carried out in the human body. This would then allow use of prodrugs that are otherwise stable in vivo but that are substrates for a tumor-targeted mutant human enzyme. We report here the first test of this concept using the human enzyme carboxypeptidase A1 (hCPA1) and prodrugs of methotrexate (MTX). Based upon a computer model of the human enzyme built from the well known crystal structure of bovine carboxypeptidase A, we have designed and synthesized novel bulky phenylalanine- and tyrosine-based prodrugs of MTX that are metabolically stable in vivo and are not substrates for wild type human carboxypeptidases A. Two of these analogs are MTX-alpha-3-cyclobutylphenylalanine and MTX-alpha-3-cyclopentyltyrosine. Also based upon the computer model, we have designed and produced a mutant of human carboxypeptidase A1, changed at position 268 from the wild type threonine to a glycine (hCPA1-T268G). This novel enzyme is capable of using the in vivo stable prodrugs, which are not substrates for the wild type hCPA1, as efficiently as the wild type hCPA1 uses its best substrates (i.e. MTX-alpha-phenylalanine). Thus, the kcat/Km value for the wild type hCPA1 with MTX-alpha-phenylalanine is 0.44 microM-1 s-1, and kcat/Km values for hCPA1-T268G with MTX-alpha-3-cyclobutylphenylalanine and MTX-alpha-3-cyclopentyltyrosine are 1.8 and 0.16 microM-1 s-1, respectively. The cytotoxic efficiency of hCPA1-268G was tested in an in vitro ADEPT model. For this experiment, hCPA1-T268G was chemically conjugated to ING-1, an antibody that binds to the tumor antigen Ep-Cam, or to Campath-1H, an antibody that binds to the T and B cell antigen CDw52. These conjugates were then incubated with HT-29 human colon adenocarcinoma cells (which express Ep-Cam but not the Campath 1H antigen) followed by incubation of the cells with the in vivo stable prodrugs. The results showed that the targeted ING-1:hCPA1-T268G conjugate produced excellent activation of the MTX prodrugs to kill HT-29 cells as efficiently as MTX itself. By contrast, the enzyme-Campath 1H conjugate was without effect. These data strongly support the feasibility of ADEPT using a mutated human enzyme with a single amino acid change.
Asunto(s)
Anticuerpos , Antimetabolitos Antineoplásicos/administración & dosificación , Carboxipeptidasas/genética , Sistemas de Liberación de Medicamentos , Isoenzimas/genética , Metotrexato/análogos & derivados , Fenilalanina/análogos & derivados , Profármacos/administración & dosificación , Animales , Antimetabolitos Antineoplásicos/uso terapéutico , Sitios de Unión , Carboxipeptidasas/administración & dosificación , Carboxipeptidasas/uso terapéutico , Carboxipeptidasas A , Bovinos , Diseño de Fármacos , Estabilidad de Medicamentos , Células HT29 , Humanos , Hidrólisis , Isoenzimas/administración & dosificación , Isoenzimas/uso terapéutico , Cinética , Sustancias Macromoleculares , Metotrexato/administración & dosificación , Metotrexato/uso terapéutico , Modelos Moleculares , Mutagénesis , Páncreas/enzimología , Jugo Pancreático/química , Fenilalanina/administración & dosificación , Fenilalanina/uso terapéutico , Profármacos/uso terapéuticoRESUMEN
Monoclonal antibody 4E3 directed against a glycosylated surface protein on human ovarian teratocarcinoma cells (CRL-1572 cell line) was conjugated to bovine carboxypeptidase A (CPA) using a 3400 Da polyethylene glycol chain bearing an N-hydroxysuccinimide group at both ends. The conjugate preparation was purified by fast protein liquid chromatography on a Superose 12/30 HR column. The 4E3-CPA conjugate was recovered in the third fraction by SDS-PAGE analysis. The specific binding of the 4E3-CPA conjugate to CRL-1572 cells was confirmed by a FACS analysis and the enzymatic activity of the conjugate remained while tested with hippuryl-L-phenylalanine. In vitro cytotoxic assays on CRL-1572 cells showed that the prodrug methotrexate-phenylalanine (MTX-Phe) alone was non-toxic (ID50 > 1000 ng ml-1) but was selectively converted to MTX when the cells were pretreated with 50 micrograms ml-1 4E3-CPA conjugate, which enhanced considerably the pharmacological activity of the prodrug with an ID50 of 70 ng ml-1. The co-culture assays with CRL-1572 and MRC-5 cells (human normal lung diploid fibroblast cell lines) demonstrated the specificity of the 4E3-CPA conjugate for the CRL-1572 cells since no cytotoxicity was observed on the MRC-5 cells. When both cell lines were mixed in ratios ranging from 1:10,000 to 1:5 (CRL-1572:MRC-5), the significant increase in the ID25 was correlated with the proportion of tumoral cells present in the cell inoculum. These results suggest that MTX-Phe combined with 4E3-CPA conjugate is a promising model for a more selective and localised anti-cancer chemotherapy based on the ADEPT concept.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Antineoplásicos/uso terapéutico , Antimetabolitos Antineoplásicos/administración & dosificación , Carboxipeptidasas/administración & dosificación , Metotrexato/análogos & derivados , Neoplasias Ováricas/tratamiento farmacológico , Fenilalanina/análogos & derivados , Profármacos/administración & dosificación , Carboxipeptidasas A , Femenino , Humanos , Metotrexato/administración & dosificación , Fenilalanina/administración & dosificación , Células Tumorales CultivadasRESUMEN
The use of antibody-enzyme conjugates directed at tumor-associated antigens to achieve site-specific activation of prodrugs to potent cytotoxic species, termed "antibody-directed enzyme prodrug therapy" (ADEPT), has attracted considerable interest since the concept was first described in 1987. Prodrug forms of both clinically used anticancer agents and novel cytotoxic compounds have been developed to take advantage of potential prodrug-generating technology employing a variety of enzymes with widely differing substrate specificities. A particular advantage of the ADEPT approach is that it may allow the use of extremely potent agents such as nitrogen mustards and palytoxin, which are too toxic to be readily used in conventional chemotherapy. Preliminary studies using an antibody-enzyme conjugate constructed with a bacterial enzyme and a murine monoclonal antibody not only have established the value of the ADEPT technique, but also have highlighted the potential problem of immunogenicity of proteins of nonhuman origin. This problem has been tackled in the first instance by the use of immunosuppressive agents, but long-term solutions are being investigated in the development of second-generation ADEPT systems, including the development of human antibody-human enzyme fusion proteins and catalytic antibodies. Such improvements, coupled with further refinement of the prodrug-drug element of the system and the wide variety of antibody-enzyme-drug combinations available, should mean that ADEPT-based approaches will form an important element of the search for the anticancer drugs of the future.
Asunto(s)
Inmunoconjugados/uso terapéutico , Profármacos/administración & dosificación , Fosfatasa Alcalina/administración & dosificación , Amidohidrolasas/administración & dosificación , Aminopeptidasas/administración & dosificación , Carboxipeptidasas/administración & dosificación , Glicósido Hidrolasas/administración & dosificación , Humanos , Nitrorreductasas/administración & dosificación , Nucleósido Desaminasas/administración & dosificación , Proteínas Recombinantes de Fusión/administración & dosificación , beta-Lactamasas/administración & dosificaciónRESUMEN
Attempts to improve the selectivity of anti-cancer agents by conjugating them to antibodies directed at tumour associated antigens have demonstrated tumour localisation but only limited therapeutic success. We report here the advantage of a 2-stage approach in which the first component combines the selective delivery of antibody with a capability to generate a cytotoxic agent from a second subsequently administered component. A bacterial enzyme, carboxypeptidase G2 (CPG2) was conjugated with F(ab')2 fragment of a monoclonal antibody directed at beta subunit of human chorionic gonadotrophin (beta-hCG) and injected into nude mice bearing hCG producing CC3 xenografts of human choriocarcinoma. Time was allowed for the conjugate to localise at tumour sites and clear from blood before injecting para-N-bis (2-chloroethyl) aminobenzoylglutamic acid. Cleavage of the glutamic acid moiety from this molecule by CPG2 released a benzoic acid mustard. Growth of the tumour which is resistant to conventional chemotherapy was markedly depressed by a single course of treatment. This demonstrates for the first time the potential of an antibody directed enzyme to activate an alkylating agent and to eradicate an established human cancer xenograft.
Asunto(s)
Ácido 4-Aminobenzoico/administración & dosificación , Aminobenzoatos/administración & dosificación , Anticuerpos Monoclonales/administración & dosificación , Carboxipeptidasas/administración & dosificación , Glutamatos/administración & dosificación , Compuestos de Mostaza Nitrogenada/administración & dosificación , Profármacos , Animales , Antineoplásicos/administración & dosificación , Línea Celular , Coriocarcinoma/tratamiento farmacológico , Humanos , Ratones , Ratones Desnudos , Profármacos/administración & dosificación , para-AminobenzoatosRESUMEN
Carboxypeptidase G2, a zinc metalloenzyme isolated from Pseudomonas sp. strain RS-16, which catalyses the hydrolytic cleavage of reduced and non-reduced folates to pteroates and L-glutamate, has been linked to a monoclonal antibody (W14A) raised to human chorionic gonadotrophin. The coupling efficiency and retention of antibody and enzymatic activities are compared for three separate methods of preparing 1:1 conjugates. Preliminary in vitro studies on the cytotoxicity of the free enzyme and the conjugated enzyme towards JAR choriocarcinoma cells are reported. Despite the limitations of the in vitro model, it could be demonstrated that a significant proportion of 10(6) choriocarcinoma cells lost viability when exposed to either free or conjugated enzyme for 72 hours at concentrations of carboxypeptidase G2 of 1-3 units ml-1 of medium.
Asunto(s)
Carboxipeptidasas/uso terapéutico , Coriocarcinoma/tratamiento farmacológico , Gonadotropina Coriónica/inmunología , Neoplasias Uterinas/tratamiento farmacológico , Anticuerpos Monoclonales/inmunología , Carboxipeptidasas/administración & dosificación , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Inmunoterapia , Técnicas In Vitro , EmbarazoRESUMEN
Thirteen patients with primary and metastatic CNS tumors have been treated with methotrexate (MTX) using three different approaches: (a) high-dose MTX with leucovorin (LV) rescue; (b) high-dose MTX with carboxypeptidase (CPDG) rescue; and (c) intraventricular administration of low doses of MTX for extended periods (concentration X time [CXT]). Eleven patients had central nervous system (CNS) lymphoma (one primary, one patient had recurrent medulloblastoma, and another patient had metastatic breast carcinoma. All 13 patients received high-dose MTX-LV rescue, while 3 patients were subsequently given MTX-CPDG. One patient received MTX by all three modalities. In patients with CNS lymphomas, complete responses (45%) and partial responses (36%) produced CNS disease-free intervals ranging from 1 to 23+ months. Survival for the complete responders has thus far ranged from 2.5 to 35 months, while the partial responders survived from 3 to 5 months. Two patients failed to respond and survived 2.5 and 3 months. Responses were obtainable with high-dose MTX-CPDG in patients resistant to MTX-LV. One patient who became sensitized to CPDG subsequently responded to MTX by intraventricular CXT administration. Thus, MTX can be effectively administered to patients with CNS tumors by several different approaches.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Linfoma/tratamiento farmacológico , Metotrexato/administración & dosificación , Adolescente , Adulto , Anciano , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/secundario , Neoplasias de la Mama/tratamiento farmacológico , Carboxipeptidasas/administración & dosificación , Femenino , Humanos , Inyecciones Intraventriculares , Leucovorina/administración & dosificación , Linfoma/mortalidad , Linfoma/secundario , Masculino , Meduloblastoma/tratamiento farmacológico , Persona de Mediana Edad , Factores de TiempoRESUMEN
Carboxypeptidase G1 (CPDG1), an enzyme that degrades folates but not the nonclassical folate antagonists triazinate (TZT, Baker's antifol) and 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine (DDMP), enhanced the antineoplastic activity of these antifolates. In 6-day cell culture experiments with Walker 256 carcinosarcoma, CPDG1 at levels up to 0.54 unit/ml showed very little inhibitory effect on growth. In the presence of 10(-7) M DDMP, the grown of Walker 256 cells was similar to that of controls, but in combination with CPDG1 (0.1 unit/ml) 80% growth inhibition was observed. TZT at a concentration of 10(-8) M did not affect the growth of Walker 256 cells. The combination of 10(-8) M TZT with CPDG1 (0.1 unit/ml), however, strongly inhibited cell growth. In experiments with rats bearing Walker 256 carcinosarcoma, the administration of CPDG1 (800 units/kg/day) from Day 1 to Day 6 resulted in no significant increase in life span. Administration of TZT in doses up to 0.05 mg/kg on Day 1 or that of DDMP up to 15 mg/kg on Days 1, 3, and 5 had no antitumor effects as measured by survival of the animals. However, CPDG1 (800 units/kg/day) from Day 1 to Day 6 in combination with TZT (0.05 mg/kg on Day 1) or DDMP (15 mg/kg on Days 1, 3, and 5) resulted in increases of 50 and 30%, respectively, in the survival of the tumor-bearing animals. These results demonstrate that CPDG1 enhances the antitumor effects of TZT or DDMP.
Asunto(s)
Carboxipeptidasas/administración & dosificación , Carcinoma 256 de Walker/tratamiento farmacológico , Antagonistas del Ácido Fólico/administración & dosificación , Pirimetamina/análogos & derivados , Triazinas/administración & dosificación , Animales , Carboxipeptidasas/farmacología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Quimioterapia Combinada , Masculino , Pirimetamina/administración & dosificación , Ratas , Factores de TiempoAsunto(s)
Antineoplásicos/administración & dosificación , Neoplasias/tratamiento farmacológico , Animales , Carboxipeptidasas/administración & dosificación , Resistencia a Medicamentos , Quimioterapia Combinada , Fluorouracilo/administración & dosificación , Ácido Fólico/metabolismo , Antagonistas del Ácido Fólico/administración & dosificación , Humanos , Leucovorina/administración & dosificación , Metotrexato/administración & dosificación , Metotrexato/metabolismo , Neoplasias/metabolismo , Nucleótidos de Uracilo/administración & dosificaciónRESUMEN
A comparison between citrovorum factor (CF) and carboxypeptidase G1 (CPDG1) rescue with respect to cerebrospinal fluid (CSF)-methotrexate (MTX) disappearance was studied in a patient with recurrent medulloblastoma who had a ventriculoperitoneal shunt. CPDG1 rescue resulted in a prolonged CSF-MTX half-life of 16.5-23 hours in comparison with CF rescue where the CSF-MTX half-life was 6.5-7.2 hours. There was a positive clinical response measured by loss of bone pain, increased physical activity, and almost complete clearing of CSF blast cells. CPDG1 rescue after high-dose MTX may provide more intense and selective treatment for meningeal neoplasms.