Preclinical development of non-viral gene therapy for patients with advanced pancreatic cancer.

Pancreatic cancer remains one of the greatest challenges in oncology for which therapeutic intervention is urgently needed. We previously demonstrated that the intra-tumoral gene transfer of somatostatin receptor 2, to combat tumor aggressiveness, or of deoxycytidine kinase and uridylate monophosphate kinase, to sensitize to gemcitabine chemotherapy, has anti-tumoral potential in experimental models of cancer. Here, we describe the development of the CYL-02 non-viral gene therapy product that comprises a DNA-plasmid encoding for the three aforementioned genes, which expression is targeted to tumor cells, and complexed with polyethyleneimine non-viral vector. We performed pre-clinical toxicology, bio-distribution, and therapeutic activity studies of CYL-02 in two rodent models of pancreatic cancer. We found that CYL-02 is safe, does not increase gemcitabine toxicity, is rapidly cleared from blood following intravenous administration, and sequestered in tumors following intra-tumoral injection. CYL-02 drives the expression of therapeutic genes in cancer cells and strongly sensitizes tumor cells to gemcitabine, both in vitro and in vivo, with significant inhibition of tumor cells dissemination. This study was instrumental for the later use of CYL-02 in patients with advanced pancreatic cancer, demonstrating that rigorous and thorough preclinical investigations are informative for the clinical transfer of gene therapies against this disease.

Radiolabeling of [18F]-fluoroethylnormemantine and initial in vivo evaluation of this innovative PET tracer for imaging the PCP sites of NMDA receptors.

INTRODUCTION: The N-methyl-D-aspartate receptor (NMDAr) is an ionotropic receptor that mediates excitatory transmission. NMDAr overexcitation is thought to be involved in neurological and neuropsychiatric disorders such as Alzheimer disease and schizophrenia. We synthesized [(18)F]-fluoroethylnormemantine ([(18)F]-FNM), a memantine derivative that binds to phencyclidine (PCP) sites within the NMDA channel pore. These sites are primarily accessible when the channel is in the active and open state. METHODS: Radiosynthesis was carried out using the Raytest® SynChrom R&D fluorination module. Affinity of this new compound was determined by competition assay. We ran a kinetic study in rats and computed a time-activity curve based on a volume-of-interest analysis, using CARIMAS® software. We performed an ex vivo autoradiography, exposing frozen rat brain sections to a phosphorscreen. Adjacent sections were used to detect NMDAr by immunohistochemistry with an anti-NR1 antibody. As a control of the specificity of our compound for NMDAr, we used a rat anesthetized with ketamine. Correlation analysis was performed with ImageJ software between signal of autoradiography and immunostaining. RESULTS: Fluorination yield was 10.5% (end of synthesis), with a mean activity of 3145 MBq and a specific activity above 355 GBq/µmol. Affinity assessment allowed us to determine [(19)F]-FNM IC50 at 6.1 10(-6)M. [(18)F]-FMN concentration gradually increased in the brain, stabilizing at 40 minutes post injection. The brain-to-blood ratio was 6, and 0.4% of the injected dose was found in the brain. Combined ex vivo autoradiography and immunohistochemical staining demonstrated colocalization of NMDAr and [(18)F]-FNM (r=0.622, p<0.0001). The highest intensity was found in the cortex and cerebellum, and the lowest in white matter. A low and homogeneous signal corresponding to unspecific binding was observed when PCP sites were blocked with ketamine. CONCLUSIONS: [(18)F]-FNM appears to be a promising tracer for imaging NMDAr activity for undertaking preclinical studies in perspective of clinical detection of neurological or neuropsychological disorders.

Fatal poisoning by vanadium.

We report here a fatal intoxication case involving ammonium vanadate. A 24-year-old woman was admitted to the Emergency Department for abdominal pain, nausea, vomiting, multiple daily diarrheas, hypoglycaemia (0.2g/L) and severe acute renal failure with glomerular filtration rate estimated at 21 ml/min. This patient had taken an undetermined amount of ammonium vanadate 12h after ingesting. She died next morning in the context of respiratory distress despite intensive care and oxygen therapy. The autopsy revealed widespread asphyxia syndrome and erosive gastritis. Determination of vanadium concentration in blood was carried out by means of mass spectrometer (ICP-MS) using rhodium ((103)Rh) as the internal standard. The vanadium concentration was 6.22 mg/L, corresponding to 6000 times higher than normal concentration in the general population. The latency and the brutality of clinical picture degradation seem to be in consideration of systemic poisoning by vanadium leading to inhibition of the cellular respiratory process.

Toxicological methods for tracing drug abuse: chromatographic, spectroscopic and biological characterisation of ecstasy derivatives.

Analysis often reveals variability in the composition of ecstasy pills from pure 3,4-methylenedioxymethamphetamine (MDMA) to mixtures of MDMA derivatives, amphetamine, and other unidentified substances. For a comprehensive toxicological analysis one needs to know all steps to MDMA synthesis which may originate impurities. The aim of this study was to synthesise and determine the chemical-physical and in vitro biological properties of a series of MDMA derivatives.3,4-methylendioxyphenyl-2-nitropropene (MDNP) was obtained by condensation of piperonal with an excess of nitroethane in the presence of ammonium acetate. MDNP was then reduced to methylenedioxyamphetamine (MDA) by LiAlH3. All compounds were analysed using HPLC and spectroscopic technique [Raman, nuclear magnetic resonance (NMR), or infrared (IR)] at all the steps of synthesis. In addition, we assessed the biological potentials of these compounds by measuring in vitro their (i) blood cell/whole blood partition coefficient, (ii) binding to plasmatic proteins (Fbp), and (iii) membrane adsorption. Chemical structure was determined with antibody fluorescence polarisation immunoassay (FPIA). This study showed the presence of solid impurities, particularly of a neurotoxic compound of Al3+ in the final products. FPIA identified the aminoethane group close to the substituted benzene ring, but did not detect the two major precursors of MDMA: MDNP and piperonal. Raman spectroscopy is an attractive alternative technique to characterise ecstasy pills and it can identify stereoisomeric forms such as cis-MDNP and trans-MDNP, which exhibit signals at 1650 cm-1 and 1300 cm-1, respectively.

Procalcitonin implication in renal cell apoptosis induced by acute pyelonephritis in children.

The aim of this biomedical trial was to clarify the physiological role of procalcitonin (PCT) in renal parenchyma apoptosis and fibrosis caused by acute childhood pyelonephritis. This prospective study enrolled 183 children. All children were treated with bi-therapy according to the French consensus on acute pyelonephritis treatment dated November 16, 1990: intra-vascular administration of ceftriaxone 50 mg/kg/day and netromicine 7 mg/kg/day during the first 48 hours, followed by specific antibiotherapy suited to antibiogram. On admission, PCT, C-reactive protein, and phospholipase A2 were quantified in serum. Scintigraphy monitoring with (99m)Tc-DMSA was performed on day 4 and 9 months later, in the presence of persistent abnormalities. On day 4, 78% presented renal parenchyma alterations and 30% renal fibrosis 9 months after admission. Paradoxically, PCT level was significantly lower in the presence of renal fibrosis due to cell apoptosis (4.19 vs 7.59 µgL(-1)). A significant increase in PCT indicated favorable progress (recovery 7.55 vs aggravation 3.34) and no difference between recovery and improvement. This result suggests the protective effect of PCT against apoptosis by nitric oxide down-regulation.

Methcathinone: a new postindustrial drug.

Methcathinone, a methyl derivative of cathinone, is an illicit drug also known as ephedrone. It is a stimulant found in the "khat" plant, Catha edulis, which can easily be synthesized from pseudoephedrine. Its intoxication is difficult to diagnose and cure properly for two reasons: (i) target consumers are usually "well-educated people" aware of the risks and precautionary measures and (ii) intoxication by cathinone derivatives of synthetic or natural (derived from the khat) origin induce misleading symptoms. As a result, documented reports of methcathinone intoxication that are based on reliable analyses are rare. This paper describes a case of reiterated coma due to an overdose of methcathinone dissolved in alcohol that was taken with bromazepam. A 29-year-old woman was admitted to an emergency department for a coma of toxic origin. Medical files showed that it was her second such episode to occur that month. Moreover, the family indicated signs of depression, incoherent behaviour and intake of "amphetamine-like" drugs. Clinical examination revealed a Glasgow coma score of 9, symmetrical reactive pupils with mydriasis and no convulsions. The patient presented with rapid respirations and her blood pressure was 93/53 mmHg. The ionogram and the blood gas analyses were normal, while the blood alcohol level was 0.167 g/dL. Urinalysis revealed the presence of benzodiazepines and a high concentration of amphetamines (methcathinone: 17.24 mg/L, ephedrine: 11.60 mg/L and methylephedrine: 11.10 mg/L). In addition, serum analysis revealed bromazepam (8.89 mg/L), methcathinone (0.50 mg/L) and methylephedrine (0.19 mg/L). This case showed that the consumption of bromazepam and alcohol altered the typical clinical symptoms of cathinone derivative intoxication, namely hypertension and convulsions. Methylephedrine, an impurity resulting from the alkylation of a primary amine, can be considered a chemical tag indicating fraudulent synthetic origin of the drug. This case describes a documented example of new addictive behaviour of "well-educated" people involving the intake of methcathinone, a postindustrial psychostimulant intentionally combined with an anticonvulsant benzodiazepine. However, this specific case suggests that in spite of a very high bromazepam concentration in presence of the potentiator alcohol, the vital respiratory function would be probably maintained, thanks to the association with methcathinone.

Toxicovigilance: new biochemical tool used in sulfonylurea herbicides toxicology studies.

In vitro toxic effects of sulfonylurea herbicides (thifensulfuron-methyl and metsulfuron-methyl) were evaluated according to a new protocol. Physiological conditions were reproduced in order to boost toxicovigilance. Sulfonylureas and their hydrolysis products were added to biological substrates such as urea, alanine, aspartic acid, alpha-ketoglutarate, oxaloacetate, pyruvate and then incubated with some specific enzymes. Addition of these sulfonylureas and their degradation products did not significantly change the enzymatic activity of the urease, aspartate-aminotransferase, glutamate dehydrogenase, malate dehydrogenase and lactate dehydrogenase. However, the acid hydrolysis products inhibited up to 95% of the activity of the alanine-aminotransferase at low concentrations (0.27 micromol L(-1)). Inhibition did not affect the mitochondrial aspartate-aminotransferase.