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1.
J Mater Sci Mater Med ; 21(5): 1599-604, 2010 May.
Article in English | MEDLINE | ID: mdl-20177742

ABSTRACT

The present study investigates the development of controlled drug delivery devices by association of bisphosphonates (BPs) with calcium-deficient apatite (CDA) to obtain a prolonged drug delivery. In a first part, we studied the microencapsulation of methylene bisphosphonic acid, our model of BPs, in biodegradable PLGA by the double emulsion (w/o/w) solvent evaporation/extraction process. Secondly, we associated BPs, either in a free form or microencapsulated, with calcium phosphate biomaterials. The association of free BPs with CDA was performed by isostatic compression at 80 MPa and we tested the interest of adding a binder, HPMC, in the formulation to reinforce the association. In parallel, microparticles were associated with calcium-deficient apatite, either by simple mixture or by isostatic compression. To compare the different formulations, in vitro dissolution studies were performed. All the formulations tested appear to be efficient to produce BPs loaded biomaterials able to deliver the drug slowly and at a constant rate. The slowest release rate (2.7% in 14 days) was obtained with the blend of microencapsulated BPs with CDA.


Subject(s)
Diphosphonates/metabolism , Drug Delivery Systems , Apatites , Biocompatible Materials/chemistry , Calcium Phosphates/chemistry , Chemistry, Pharmaceutical , Dosage Forms , Drug Administration Routes , Drug Compounding , Lactic Acid , Physiological Phenomena , Polyglycolic Acid , Polylactic Acid-Polyglycolic Acid Copolymer
2.
J Biomed Mater Res B Appl Biomater ; 84(1): 1-6, 2008 Jan.
Article in English | MEDLINE | ID: mdl-17907206

ABSTRACT

Interconnection, one of the main structural features of macroporous calcium-phosphate ceramics, contributes to the biological and physicochemical properties of bone substitutes. As no satisfactory method exists for evaluating this feature, analysis was performed to determine the permeability, tortuosity, and equivalent diameter of interconnecting channels, that is the parameters that appear to be representative of the way pores are linked. The testing of two ceramics with similar porosity levels revealed important differences in all three interconnection parameters. One ceramic showed poor permeability, corresponding to a small equivalent diameter for interconnecting channels in conjunction with a high tortuosity factor, while the other displayed high permeability, a large diameter for interconnecting channels, and a low tortuosity factor. The methodology used, which can be applied to the quantification of interconnection in all calcium-phosphate ceramics, constitutes the first step in a complete study of the role of this feature in cellular colonization of the ceramic, matrix dissolution, and drug release from the calcium-phosphate matrix.


Subject(s)
Biocompatible Materials/chemistry , Calcium Phosphates/chemistry , Ceramics/chemistry , Algorithms , Biocompatible Materials/chemical synthesis , Calcium Phosphates/chemical synthesis , Ceramics/chemical synthesis , Diffusion , Iodides/chemistry , Mercury/chemistry , Models, Chemical , Permeability , Porosity , Spectrometry, Mass, Electrospray Ionization
3.
J Microencapsul ; 22(8): 841-52, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16423756

ABSTRACT

The present study investigates vancomycin microencapsulation in biodegradable PLAGA microparticles. To optimize encapsulation efficiency by the double emulsion (w/o/w) solvent evaporation/extraction process, two parameters were studied: surfactant (Span 80) rate and external aqueous phase saturation. In vitro dissolution studies, laser granulometry and scanning electron microscopy were performed to characterize the microparticles. The best results were obtained by stabilizing the first emulsion with 0.5% Span 80 and saturating the external phase with sodium chloride. Such parameters allowed a 95% drug encapsulation efficiency. This process yielded round microparticles with a mean diameter of approximately 170 microm and presenting a smooth surface without any pores. Moreover, this formulation induces a sustained drug release at a constant rate over a period of 10 days. Such materials could be associated with biphasic calcium phosphate granules to form an antibiotic-loaded injectable bone substitute offering a long-term activity in situ.


Subject(s)
Anti-Bacterial Agents , Microspheres , Polyglactin 910 , Vancomycin , Biocompatible Materials , Biodegradation, Environmental , Bone Transplantation , Delayed-Action Preparations , Drug Compounding/methods , Drug Stability , Humans , Microscopy, Electron, Scanning/methods , Particle Size , Sodium Chloride , Surface Properties
4.
Biomaterials ; 24(3): 443-9, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12423599

ABSTRACT

Vancomycin encapsulation in biodegradable poly(epsilon-caprolactone) microparticles (200 microm mean diameter) was most efficient with a simple emulsion technique that dispersed 122.5 mg/g of polymer. Scanning electron micrographs showed smooth or pitted particles. Dissolution studies were correlated with microparticle morphology, indicating higher release with pitted particles when vancomycin was encapsulated in a dissolved state. The cytocompatibility of these poly(epsilon-caprolactone) microparticles was demonstrated by a direct contact cytotoxic assay. This material can be considered as an efficient drug delivery system for bone implantation.


Subject(s)
Biocompatible Materials/pharmacology , Caproates/chemistry , Caproates/pharmacology , Drug Delivery Systems , Lactones/chemistry , Lactones/pharmacology , Vancomycin/pharmacology , Absorbable Implants , Animals , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/pharmacology , Bone Substitutes , Cell Line , Fibroblasts/metabolism , Kinetics , Mice , Microscopy, Electron, Scanning , Spectrophotometry , Time Factors , Vancomycin/administration & dosage
5.
Cancer Gene Ther ; 7(8): 1120-6, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10975672

ABSTRACT

Gene therapy using the herpes simplex virus thymidine kinase (HSV-TK) gene in combination with the drug ganciclovir (GCV) is a promising approach for the treatment of cancer-inducing gliomas, a tumor with a poor prognosis. In an attempt to limit the toxic effects on normal tissues, we constructed a recombinant adenoviral vector, Adgfa2TK, in which the HSV-TK gene is driven by the promoter for the gene encoding glial fibrillary acidic protein, an intermediate filament protein expressed primarily in astrocytes. Infection by Adgfa2TK of a glial cell line (C6) and a non-glial cell line (MDA-MB-231) revealed markedly increased expression of HSV-TK in glial cells as determined by Western blot. In comparison, high HSV-TK protein levels were produced in both cell lines after infection with a control virus, AdCMVTK, in which the constitutive cytomegalovirus viral promoter was used to direct HSV-TK expression. Infection of two glial cell lines (C6, U251) and two non-glial cell lines (HepG2, MDA-MB-231) with Adgfa2TK followed by GCV treatment revealed high toxicity in glial cell lines (50% growth inhibitory concentration: <2 microg/mL of GCV) with little or no toxicity (50% growth inhibitory concentration: >75 microg/mL) in the non-glial cell lines. In vivo, injection of Adgfa2TK into C6 tumors grown in nude mice followed by intraperitoneal GCV treatment significantly repressed tumor growth compared with the controls. Adgfa2TK may be useful for directing expression of the HSV-TK gene to gliomas.


Subject(s)
Adenoviridae/genetics , Astrocytes/pathology , Brain Neoplasms/pathology , Genetic Vectors , Glioma/pathology , Promoter Regions, Genetic , Animals , Antiviral Agents/pharmacology , Base Sequence , DNA Primers , Ganciclovir/pharmacology , Glial Fibrillary Acidic Protein/genetics , Humans , In Vitro Techniques , Mice , Mice, Nude , Rats , Recombination, Genetic , Tumor Cells, Cultured
6.
Clin Cancer Res ; 6(5): 2012-20, 2000 May.
Article in English | MEDLINE | ID: mdl-10815927

ABSTRACT

7-Ethyl-10[4-(1-piperidino)-1-piperidino] carbonyloxy-camptothecin (CPT-11), a DNA topoisomerase I inhibitor, undergoes several metabolic pathways to generate conjugated and unconjugated derivatives that could be excreted from the body. The objective of this study was to determine the oxidative metabolites of CPT-11 recovered in human urine samples and to identify cytochrome P450 (CYP) involved in their formation. In addition to the already known metabolites of CPT-11 [SN-38, SN-38-G, 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]carbonyloxycamptothecin (APC), and 7-ethyl-10-(4-amino-1-piperidino) carbonyloxycamptothecin (NPC)], we isolated three oxidized metabolites from the urine of two children and two adults given CPT-11. M1 and M2 (molecular weight, 602) were hydroxylated, respectively, on the CPT moiety and on the terminal piperidine ring of CPT-11. M3 had a molecular mass of 602, but its urine concentration in patients was too low to establish its chemical structure by liquid chromatography/mass spectrometry. In vitro incubations with cells expressing CYP2C8, CYP2C9, CYP1A1, CYP1A2, or CYP3A7 did not produce any detectable metabolites. Only CYP3A4 produced both APC and NPC, resulting from the oxidation of the piperidinylpiperidine side chain of CPT-11 along with metabolite M2. The metabolism of CPT-11 by CYP3A5 was markedly different because neither APC or NPC nor M2 was produced, whereas only one new metabolite, M4 (molecular weight, 558), was generated by de-ethylation of the CPT moiety. No previous study has reported the presence of the M4 metabolite. Production of APC, NPC, M2, and M4 was prevented by ketoconazole, a specific CYP3A inhibitor. The parameters of CPT-11 biotransformation into M2 and M4 were examined using cell lines expressing, respectively, with CYP3A4 and CYP3A5, indicating that CPT-11 is preferentially metabolized by CYP3A4. In conclusion, CYP3A plays a major role in the metabolism of CPT-11, with some differences of the metabolic profile exhibited by 3A4 and 3A5.


Subject(s)
Antineoplastic Agents, Phytogenic/metabolism , Camptothecin/analogs & derivatives , Cytochrome P-450 Enzyme System/metabolism , Mixed Function Oxygenases/metabolism , Neoplasms/drug therapy , Adolescent , Aged , Antineoplastic Agents, Phytogenic/therapeutic use , Camptothecin/metabolism , Camptothecin/therapeutic use , Camptothecin/urine , Cell Line , Child, Preschool , Chromatography, High Pressure Liquid , Chromatography, Liquid , Cytochrome P-450 CYP3A , Female , Humans , Irinotecan , Male , Mass Spectrometry , Microsomes, Liver/enzymology , Microsomes, Liver/metabolism , Neoplasms/metabolism , Topoisomerase I Inhibitors
7.
J Med Chem ; 43(8): 1604-10, 2000 Apr 20.
Article in English | MEDLINE | ID: mdl-10780917

ABSTRACT

Several glycosyl derivatives of squamocin (1) have been synthesized by glycosylation under Lewis acid catalysis with two different 1-O-acetyl sugars. Separation of these compounds has been achieved by HPLC and centrifugal partition chromatography (CPC). A detailed NMR, ESIMS, and LSIMS study allowed complete structural elucidations. The cytotoxic activity of the glycosyl derivatives was investigated and compared with that of squamocin and dihydrosquamocin against human epidermoid carcinoma cells (KB), African green monkey (Cercopithecus aethiops) kidney epithelial cells (VERO), and mouse lymphocytic leukemia cells (L1210). The antiproliferative effects of some derivatives were studied on cell cycles in mouse lymphocytic leukemia cells (L1210).


Subject(s)
Antineoplastic Agents/chemical synthesis , Furans/chemical synthesis , Lactones/chemical synthesis , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Cycle/drug effects , Chlorocebus aethiops , Drug Screening Assays, Antitumor , Furans/chemistry , Furans/pharmacology , Glycosylation , Humans , Lactones/chemistry , Lactones/pharmacology , Magnetic Resonance Spectroscopy , Mass Spectrometry , Mice , Tumor Cells, Cultured , Vero Cells
8.
J Natl Cancer Inst ; 92(8): 642-7, 2000 Apr 19.
Article in English | MEDLINE | ID: mdl-10772682

ABSTRACT

BACKGROUND: Cisplatin (cis-diamminedichloroplatinum) is one of the most active agents against a broad range of malignancies, including ovarian cancer. Cisplatin resistance appears to be associated with several molecular alterations, including overexpression of metallothionein, a metal-binding protein. In the present study, we attempted to take advantage of metallothionein overexpression to overcome cisplatin resistance. METHODS: Using a virus-free system (liposomes), we sought to express the suicide gene, thymidine kinase (TK), driven by the promoter of the human metallothionein IIa (hMTIIa) gene using the pMT-TK plasmid. We used cisplatin-resistant human ovarian carcinoma cells as a model. RESULTS: We first analyzed metallothionein expression using a ribonuclease protection assay. In comparison to parental cells, the cisplatin-resistant cells were found to have increased expression of metallothionein messenger RNA (mRNA). Metallothionein overexpression in these cells was not associated with an increased copy number of the hMTIIa gene or with different transfection efficiencies. Furthermore, we showed by reverse transcription-polymerase chain reaction analysis that transfection of the pMT-TK plasmid results in a 56-fold higher expression of thymidine kinase mRNA in cisplatin-resistant cells compared with parental cells, consistent with increased metallothionein promoter-mediated transactivation in the cisplatin-resistant cells. Transfection of resistant cells with pMT-TK or a control plasmid (pCD3-TK) resulted in a marked sensitization to ganciclovir, with a 50% cell growth-inhibitory concentration (IC(50)) of 20 microg/mL and 9 microg/mL, respectively. Transfections of the cisplatin-sensitive cells resulted in no sensitization to ganciclovir with pMT-TK (IC(50) 200 microg/mL) and a high sensitization with pCD3-TK (IC(50) = 6 microg/mL). CONCLUSION: These studies suggest that pMT-TK gene therapy may provide an alternative treatment for cisplatin-refractory ovarian tumors.


Subject(s)
Cisplatin/pharmacology , Genetic Therapy , Metallothionein/genetics , Ovarian Neoplasms/genetics , Promoter Regions, Genetic , Thymidine Kinase/genetics , Drug Resistance, Neoplasm , Female , Ganciclovir/pharmacology , Humans , Liposomes/administration & dosage , Prodrugs/metabolism , RNA, Messenger/analysis , Simplexvirus/enzymology , Thymidine Kinase/metabolism , Transcriptional Activation , Transfection , Tumor Cells, Cultured
9.
Eur J Med Chem ; 35(1): 137-46, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10733610

ABSTRACT

New nitrosoureido derivatives of di- or tri-deoxy-sugars have been synthesized. Very potent antitumour activity against L1210 leukaemia was exhibited by the compounds derived from methyl 3-amino-3, 4-dideoxy-beta- and alpha- and 4-amino-2,4-dideoxy-beta- and alpha-D-arabino-hexopyranosides, 24, 26, 28 and 29, respectively. In further evaluation against B16 melanocarcinoma bearing mice, only compounds 24 and 26 displayed significant activity. Owing to its lower acute toxicity, methyl 3-[3-(2-chloroethyl)-3-nitrosoureido]-3, 4-dideoxy-beta-D-arabino-hexopyranoside 24 appeared as the best candidate for preclinical studies.


Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/therapeutic use , Glucosides/chemical synthesis , Glucosides/therapeutic use , Nitrosourea Compounds/chemical synthesis , Nitrosourea Compounds/therapeutic use , Animals , Carmustine/therapeutic use , Leukemia L1210/drug therapy , Melanoma, Experimental/drug therapy , Mice , Mice, Inbred C57BL , Molecular Structure , Structure-Activity Relationship
10.
Drug Dev Ind Pharm ; 25(8): 897-904, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10434133

ABSTRACT

The purpose of this study was to develop an in vitro perfusion technique or "continuous-flow adhesion cell" model to predict the in vivo performances of different mucoadhesive drug delivery systems based on hydrogels. Two studies were performed, either using a rabbit small intestine or a polyethylene surface; the adhesion of four gels--two poly(acrylic acid)s (PAAs) (carbomer [CM] and polycarbophil [PC]), an ethyleneoxide-propyleneoxide block copolymer (Poloxamer 407 [PM]), and a polysaccharide (scleroglucane [SG])--were evaluated. In this respect, scleroglucane was used as a control. The adhesiveness of the different gels for both supports is in accordance with that described in the literature, that is, polycarbophil adhered more strongly than carbomer, which itself adhered more strongly than poloxamer. This study proved that the gels adhere more strongly to the polyethylene tube than to the rabbit small intestine, thus indicating that evidence for adhesion properties does not need any presence of mucus. Therefore, our in vitro model could be a good method, more precise and more simple than an ex vivo technique, to predict the bioadhesion of gelified devices.


Subject(s)
Drug Delivery Systems/instrumentation , Hydrogels/chemistry , Perfusion/instrumentation , Adhesiveness , Animals , Diffusion , Evaluation Studies as Topic , In Vitro Techniques , Intestine, Small/chemistry , Polyethylenes , Polymers , Rabbits
11.
Br J Cancer ; 79(5-6): 787-92, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10070870

ABSTRACT

High-dose busulphan-containing chemotherapy regimens have shown high response rates in children with relapsed or refractory neuroblastoma, Ewing's sarcoma and medulloblastoma. However, the anti-tumour activity of busulfan as a single agent remains to be defined, and this was evaluated in athymic mice bearing advanced stage subcutaneous paediatric solid tumour xenografts. Because busulphan is highly insoluble in water, the use of several vehicles for enteral and parenteral administration was first investigated in terms of pharmacokinetics and toxicity. The highest bioavailability was obtained with busulphan in DMSO administered i.p. When busulphan was suspended in carboxymethylcellulose and given orally or i.p., the bioavailability was poor. Then, in the therapeutic experiments, busulphan in DMSO was administered i.p. on days 0 and 4. At the maximum tolerated total dose (50 mg kg(-1)), busulphan induced a significant tumour growth delay, ranging from 12 to 34 days in the three neuroblastomas evaluated and in one out of three medulloblastomas. At a dose level above the maximum tolerated dose, busulphan induced complete and partial tumour regressions. Busulphan was inactive in a peripheral primitive neuroectodermal tumour (PNET) xenograft. When busulphan pharmacokinetics in mice and humans were considered, the estimated systemic exposure at the therapeutically active dose in mice (113 microg h ml(-1)) was close to the mean total systemic exposure in children receiving high-dose busulphan (102.4 microg h ml(-1)). In conclusion, busulphan displayed a significant anti-tumour activity in neuroblastoma and medulloblastoma xenografts at plasma drug concentrations which can be achieved clinically in children receiving high-dose busulphan-containing regimens.


Subject(s)
Brain Neoplasms/drug therapy , Busulfan/blood , Busulfan/therapeutic use , Medulloblastoma/drug therapy , Neuroblastoma/drug therapy , Neuroectodermal Tumors, Primitive/drug therapy , Administration, Oral , Animals , Biological Availability , Brain Neoplasms/blood , Busulfan/administration & dosage , Busulfan/pharmacokinetics , Carboxymethylcellulose Sodium , Dimethyl Sulfoxide , Female , Humans , Injections, Intraperitoneal , Medulloblastoma/blood , Mice , Mice, Nude , Neuroblastoma/blood , Neuroectodermal Tumors, Primitive/blood , Solubility , Transplantation, Heterologous , Tumor Cells, Cultured
12.
J Clin Pharmacol ; 39(1): 47-54, 1999 Jan.
Article in English | MEDLINE | ID: mdl-9987700

ABSTRACT

Trecovirsen, a 25-mer antisense phosphorothioate oligonucleotide targeted at the gag site of the HIV gene, was administered to HIV-positive volunteers as an i.v. infusion. Single doses ranged from 0.1 to 2.5 mg/kg in an ascending escalation in cohorts of 6 to 12 subjects. Plasma trecovirsen concentrations and pharmacokinetic parameters could be assessed at doses > or = 0.3 mg/kg. Peak plasma concentrations and AUC values increased disproportionately with increasing dose while elimination half-life increased and plasma clearance decreased, indicating a saturable process over this dose range. The only significant adverse event observed was an isolated, transitory increase in activated partial thromboplastin time at doses > or = 2.0 mg/kg that was related to plasma trecovirsen concentrations and is attributed to the polyanionic character of the molecule. Thus, trecovirsen administration was well tolerated in single i.v. doses up to 2.5 mg/kg.


Subject(s)
Anti-HIV Agents/pharmacokinetics , HIV Seropositivity/drug therapy , Oligodeoxyribonucleotides, Antisense/pharmacokinetics , Thionucleotides/pharmacokinetics , Adult , Anti-HIV Agents/adverse effects , Area Under Curve , Cross-Over Studies , Dose-Response Relationship, Drug , Female , Headache/chemically induced , Humans , Infusions, Intravenous , Male , Metabolic Clearance Rate , Middle Aged , Oligodeoxyribonucleotides, Antisense/adverse effects , Partial Thromboplastin Time , Thionucleotides/adverse effects
13.
Cancer Res ; 58(20): 4577-80, 1998 Oct 15.
Article in English | MEDLINE | ID: mdl-9788604

ABSTRACT

Gene therapy using the herpes simplex virus thymidine kinase gene (HSV-TK) is a promising new approach for the treatment of gliomas, a tumor type with a poor prognosis. To limit the toxic effects of this procedure, it is desirable to restrict expression of the HSV-TK gene to the target cells. This can be accomplished by use of the promoter of the glial fibrillary acidic protein gene, an intermediate filament protein expressed primarily in astrocytes. A plasmid containing the HSV-TK gene, driven by the human glial fibrillary acidic protein promoter gfa2, was lipofected into glioma cell lines and into an ovarian cancer cell line. Treatment with ganciclovir showed efficient killing of glioma cells, with no effect on the ovarian cells. Thus, the gfa2 promoter is a promising candidate for directing expression of toxic genes to gliomas.


Subject(s)
Astrocytes/metabolism , Genetic Therapy , Glioma/therapy , Simplexvirus/enzymology , Thymidine Kinase/genetics , Ganciclovir/pharmacology , Glial Fibrillary Acidic Protein/analysis , Glial Fibrillary Acidic Protein/genetics , Glioma/pathology , Humans , Promoter Regions, Genetic , Tumor Cells, Cultured
14.
Ann Biol Clin (Paris) ; 56(3): 321-7, 1998.
Article in French | MEDLINE | ID: mdl-9754264

ABSTRACT

Hypercholesterolemia increases the oxidation of low density lipoprotein (LDL) which subsequently leads to atherogenesis. The oxidized LDL are also known to increase in vitro macrophage synthesis of glutathione. The purpose of this study was to investigate the relationship between lipid parameters and the glutathione system (glutathione, glutathione S-transferase) in total blood and within leukocytes. The glutathione and glutathione S-transferase were evaluated by spectrophotometric methods in sixty-two healthy volunteers (32 women, 30 men, mean age 39.9 +/- 7.7). No correlation was found between the level of blood cholesterol and the values of the blood glutathione system. However, a positive correlation between the values of glutathione and glutathione S-transferase in leukocytes and the blood cholesterol level was only found in women (r = 0.55 and r = 0.50 respectively, p < 0.01). We also found in men a positive correlation between body mass index and glutathione S-transferase in total blood and within leukocytes (r = 0.38, p < 0.05, r = 0.5, p < 0.01 respectively). No correlation was found between age, smoking and the values of the glutathione system. Our results suggest that the glutathione system in leukocytes is related to blood cholesterol levels. The fact that this positive correlation was only observed in women points to a possible role of estrogens in the regulation of the glutathione system which merits to be further studied.


Subject(s)
Cholesterol/blood , Glutathione Transferase/blood , Glutathione/blood , Leukocytes/chemistry , Adult , Blood Glucose/analysis , Body Mass Index , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Female , Humans , Male , Middle Aged , Reference Values , Sex Characteristics , Triglycerides/blood
15.
Anticancer Res ; 18(3A): 1833-8, 1998.
Article in English | MEDLINE | ID: mdl-9673412

ABSTRACT

During inflammation and infection, overexpression of the tumor necrosis factor (TNF) is associated with changes in cytochromes P-450 levels in rat and human hepatocytes. The aim of this study was to investigate the effect of TNF on the expression of the glutathione-S-transferases (GSTs) in rat hepatocytes. TNF was added in vitro alone or simultaneously with phenobarbital (PB) into hepatocytes in primary culture or in vivo, before TNF, injected directly to rats. GST activity was assayed by spectrophotometry; protein GSTs alpha, mu and pi were evaluated by immunoblotting. When TNF was added alone to rat hepatocytes in vitro, total GST activity and GST alpha levels were not affected, while GST mu protein levels significantly decreased by 35%. GST pi protein was undetectable in hepatocytes whether treated or not with TNF. When PB was administered in vitro simultaneously to rat hepatocytes with TNF, the decrease observed for GST mu subunit was suppressed while total GST activity and GST alpha content were not affected. When hepatocytes were treated with TNF after PB given in vivo directly to the rat by i.p. injection, GST activity and GSTs subunits were induced by PB, while TNF did not exert any effect. These results indicate that TNF has an inhibitory effect on GST mu and PB abrogates this effect in primary cultured rat hepatocytes. Then, PB could prevent some TNF toxic effects.


Subject(s)
Glutathione Transferase/biosynthesis , Isoenzymes/biosynthesis , Liver/enzymology , Phenobarbital/pharmacology , Tumor Necrosis Factor-alpha/pharmacology , Animals , Cells, Cultured , Cytochrome P-450 Enzyme System/biosynthesis , Glutathione Transferase/antagonists & inhibitors , Humans , Injections, Intraperitoneal , Isoenzymes/antagonists & inhibitors , Kinetics , Macromolecular Substances , Male , Phenobarbital/administration & dosage , Rats , Rats, Sprague-Dawley , Tumor Necrosis Factor-alpha/antagonists & inhibitors
16.
Biochimie ; 80(3): 271-80, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9615866

ABSTRACT

Although the prognosis of childhood cancers has dramatically improved over the last three decades, new active drugs are needed. Camptothecins represent a very attractive new class of anticancer drugs to develop in paediatric oncology. The preclinical and clinical development of two of these DNA-topoisomerase I inhibitors, i.e. topotecan and irinotecan, is ongoing in paediatric malignancies. Here we review the currently available results of this evaluation. Topotecan proved to be active against several paediatric tumour xenografts. In paediatric phase I studies exploring several administration schedules, myelosuppression was dose-limiting. The preliminary results of topotecan evaluation in phase II study showed antitumour activity in neuroblastoma (response rate: 15% at relapse and 37% in newly diagnosed patients with disseminated disease) and in metastatic rhabdomyosarcoma (40% in untreated patients). Topotecan-containing drug combinations are currently investigated. Irinotecan displayed a broad spectrum of activity in paediatric solid tumour xenografts, including rhabdo-myosarcoma, neuroblastoma, peripheral primitive neuroectodermal tumour, medulloblastoma, ependymoma, malignant glioma and juvenile colon cancer. For several of these histology types, tumour-free survivors have been observed among animals bearing an advanced-stage tumour at time of treatment. The clinical evaluation of irinotecan in children is ongoing. Irinotecan undergoes a complex in vivo biotransformation involving several enzyme systems, such as carboxylesterase, UDPGT and cytochrome P450, in children as well as in adults. Preclinical studies of both drugs have shown that their activity was schedule-dependent. The optimal schedule of administration is an issue that needs to be addressed in children. In conclusion, the preliminary results of the paediatric evaluation of camptothecin derivatives show very encouraging results in childhood malignancies. The potential place of camptothecins in the treatment of paediatric malignant tumours is discussed.


Subject(s)
Camptothecin/analogs & derivatives , Neoplasms/drug therapy , Topotecan/therapeutic use , Animals , Camptothecin/therapeutic use , Child , Clinical Trials, Phase I as Topic , Clinical Trials, Phase II as Topic , Enzyme Inhibitors , Humans , Irinotecan , Topoisomerase I Inhibitors
17.
Anticancer Res ; 18(1A): 283-8, 1998.
Article in English | MEDLINE | ID: mdl-9568091

ABSTRACT

The purpose of this study was to find out whether the glutathione (GSH), in red blood cells could predict the response to neoadjuvant chemotherapy cisplatin/5-fluorouracil (CDDP/5-FU) in patients with head and neck squamous cell carcinoma (HNSCC). Three courses of induction chemotherapy with CDDP/5-FU were administered and followed by surgery and radiotherapy or radiotherapy alone, in 51 patients with HNSCC. GSH was measured by spectrophotometry in red blood cell before any treatment (Sample 1: S1), after each course of chemotherapy (S2, S3, S4). Our results showed that GSH was the same at diagnosis in patients with complete or partial response (OR) compared to those with stable or progressive disease (NR). With regard to evolution of the GSH during the 3 courses of CT a significant difference was found between courses (S2: 5.06 +/- 0.35 vs S4 = 3.61 +/- 0.4 mumol/g haemoglobin, p < 0.05). When we separated our patients into OR and NR, a significant difference was found over the 3 courses of chemotherapy for GSH content. Non responder patients showed decreased GSH content at the end of the treatment, (S2: 5 +/- 0.5 vs S4: 2.2 +/- 0.4 mumol/g haemoglobin, p < 0.05) while OR were stable. In conclusion, red blood cell GSH seems to have no early predictive value for chemoresponse to neoadjuvant chemotherapy CDDP/5-FU in HNSCC.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma, Squamous Cell/drug therapy , Cisplatin/administration & dosage , Fluorouracil/administration & dosage , Glutathione/blood , Head and Neck Neoplasms/drug therapy , Adult , Aged , Combined Modality Therapy , Drug Resistance, Neoplasm , Female , Hemoglobins/analysis , Humans , Male , Middle Aged
18.
Clin Cancer Res ; 4(2): 463-8, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9516937

ABSTRACT

Fotemustine is a chloroethylnitrosourea with antitumor activity in disseminated melanoma and adult primary brain tumors. Because new drugs are required for the treatment of medulloblastoma in children, we evaluated the preclinical antitumor activity of fotemustine in four s.c. medulloblastoma xenografts, in comparison with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Both drugs were administered as a single i.p. injection to nude mice bearing advanced-stage tumor. Fotemustine displayed significant antitumor activity in three of four medulloblastoma xenografts; two, IGRM34 and IGRM57, were highly sensitive, with 37 and 100% tumor-free survivors, respectively, more than 120 days after treatment at the highest nontoxic dose (50 mg/kg). Fotemustine was also highly active in a malignant glioma xenograft (IGRG88; five of six tumor-free survivors on day 177). Fotemustine proved to be significantly more active than BCNU in IGRM34 and the glioma xenograft IGRG88. The DNA repair protein O6-alkylguanine-DNA alkyltransferase (ATase) was detected in all tumor xenografts, ranging in activity from 6 to 892 fmol/mg protein. The high in vivo sensitivity to fotemustine and BCNU observed in three xenografts was clearly associated with a low ATase activity (> 20 fmol/mg), whereas the two poorly sensitive or refractory medulloblastoma xenografts showed high ATase activity (> 500 fmol/mg). Alkylpurine-DNA N-glycosylase activity was detected in all tumor xenografts but at levels ranging only from 513 to 1105 fmol/mg/h; no consistent relationship was found between alkylpurine-DNA N-glycosylase activity and the in vivo sensitivity to the two chloroethylnitrosoureas. The improved activity and tolerance of fotemustine in comparison with BCNU in pediatric medulloblastoma xenografts strongly support the clinical development of this agent in children with brain tumors, in which ATase should be examined as a potential prognostic indicator.


Subject(s)
Antineoplastic Agents/pharmacology , Brain Neoplasms/drug therapy , Brain Neoplasms/enzymology , Cerebellar Neoplasms/drug therapy , Cerebellar Neoplasms/enzymology , DNA Glycosylases , Glioma/drug therapy , Glioma/enzymology , Medulloblastoma/drug therapy , Medulloblastoma/enzymology , N-Glycosyl Hydrolases/metabolism , Nitrosourea Compounds/pharmacology , O(6)-Methylguanine-DNA Methyltransferase/metabolism , Organophosphorus Compounds/pharmacology , Animals , Antineoplastic Agents/toxicity , Antineoplastic Agents, Alkylating/pharmacology , Carmustine/pharmacology , DNA Repair , Drug Screening Assays, Antitumor , Female , Humans , Male , Mice , Middle Aged , Neoplasm Transplantation , Nitrosourea Compounds/toxicity , Organophosphorus Compounds/toxicity , Transplantation, Heterologous , Tumor Cells, Cultured
19.
Int J Cancer ; 73(1): 156-63, 1997 Sep 26.
Article in English | MEDLINE | ID: mdl-9334824

ABSTRACT

The anti-tumor activity of irinotecan (CPT-11), a DNA-topoisomerase 1 inhibitor, was evaluated in 5 advanced stage subcutaneous medulloblastoma xenografts in nude mice, using different schedules of administration. With a 5-day schedule, the highest i.v. dose tested (40 mg kg-1 day-1) induced complete regressions in all xenografts but 1, and delays in tumor growth always exceeded 30 days. Two xenografts, IGRM11 and IGRM33, were highly sensitive, and animals survived tumor-free beyond 120 days after treatment. CPT-11 clearly retained its anti-tumor activity at a lower dosage (27 mg kg-1 day-1). CPT-11 was significantly more active than cyclophosphamide, thiotepa and etoposide against the 3 xenografts evaluated. To study the schedule dependency of its anti-tumor activity, CPT-11 was given i.v. at the same total doses over the same period (33 days) using either a protracted or a sequential schedule in IGRM34-bearing mice. With a dose of 10 mg kg-1 day-1 given on days 0-4, days 7-11, days 21-25 and days 28-32 (total dose, 200 mg kg-1), 3 of 6 animals were tumor free on day 378. The same total dose given with a sequential schedule, i.e., 20 mg kg-1 day-1 on days 0-4 and days 28-32, failed to induce complete regression. The plasma pharmacokinetics of CPT-11 and SN-38 were studied in IGRM34-bearing animals after a single i.v. dose of 10 and 40 mg kg-1. The plasma clearance rate of CPT-11 was dose dependent. The ratio between the SN-38 and CPT-11 area under the curve in plasma was 0.4-0.65, i.e., significantly higher than that observed in humans at the maximum tolerated dose (0.01-0.05). Conversely, this ratio was 10-fold lower in tumor than in plasma. Clinical development of irinotecan is warranted in pediatric malignancies.


Subject(s)
Antineoplastic Agents, Phytogenic/therapeutic use , Camptothecin/analogs & derivatives , Enzyme Inhibitors/therapeutic use , Medulloblastoma/drug therapy , Topoisomerase I Inhibitors , Animals , Camptothecin/administration & dosage , Camptothecin/pharmacokinetics , Camptothecin/therapeutic use , Child , Dose-Response Relationship, Drug , Drug Administration Schedule , Female , Humans , Irinotecan , Male , Mice , Mice, Nude , Neoplasm Transplantation , Transplantation, Heterologous
20.
J Photochem Photobiol B ; 39(3): 249-57, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9253200

ABSTRACT

The pharmacokinetics of a water-soluble derivative obtained from meta-(tetrahydroxyphenyl)chlorin (m-THPC) was evaluated in in vitro and in vivo studies. Cytoplasm fluorescence was measured in two cell models (L1210 and HT29) using a flow cytometer and a confocal microspectrofluorometer. Cells were incubated with the compound at several doses (0-150 micrograms ml-1 for flow cytometry) and for several time periods (0-6 h for microspectrofluorometry). For in vivo studies, nude mice were grafted with human adenocarcinoma 15 days before intraperitoneal injection of polyethylene glycol-m-THPC (PEG-m-THPC). Fluorescence was recorded through an optical fibre spectrofluorometer using the 660 nm peak for detection. In in vitro studies, the fluorescence was found to be proportional to the dose. Maximum fluorescence was recorded in L1210 cells earlier and more intensely than in HT29 cells (3 h at 202 +/- 14 counts s-1 and 5 h at 43 +/- 2.15 counts s-1 respectively). Concerning in vivo studies, maximum tumour fluorescence was observed 24 h after injection (3568 +/- 178 counts s-1). Selectivity was expressed by the calculated tumour-to-skin and tumour-to-muscle ratios. The time taken to observe the maximum ratios (2.95 +/- 0.16 for tumour-to-skin and 6.61 +/- 0.3 for tumour-to-muscle) was almost the same as the time taken to observe the maximum fluorescence in the tumour. Studies are in progress to correlate these results with photodynamic effects.


Subject(s)
Antineoplastic Agents/pharmacokinetics , Mesoporphyrins/pharmacokinetics , Radiation-Sensitizing Agents/pharmacokinetics , Animals , Antineoplastic Agents/chemistry , Cytoplasm/metabolism , Flow Cytometry , Humans , In Vitro Techniques , Kinetics , Male , Mesoporphyrins/chemistry , Mice , Mice, Nude , Muscles/metabolism , Neoplasms, Experimental/metabolism , Polyethylene Glycols , Radiation-Sensitizing Agents/chemistry , Skin/metabolism , Spectrometry, Fluorescence
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