Phase-I/II radio-immunotherapy study with Iodine-131-labeled anti-CEA monoclonal antibody F6 F(ab')2 in patients with non-resectable liver metastases from colorectal cancer.

Experimental studies in nude mice with human colon-carcinoma grafts demonstrated the therapeutic efficiency of F(ab')2 fragments to carcinoembryonic antigen (CEA) labeled with a high dose of 131Iodine. A phase I/II study was designed to determine the maximum tolerated dose of 131I-labeled F(ab')2 fragments (131I-F(ab')2) from anti-CEA monoclonal antibody F6, its limiting organ toxicity and tumor uptake. Ten patients with non-resectable liver metastases from colorectal cancer (9 detected by CT scan and 1 by laparotomy) were treated with 131I-F(ab')2, doses ranging from 87 mCi to 300 mCi for the first 5 patients, with a constant 300-mCi dose for the last 5 patients. For all the patients, autologous bone marrow was harvested and stored before treatment. Circulating CEA ranged from 2 to 126 ng/ml. No severe adverse events were observed during or immediately following infusion of therapeutic doses. The 9 patients with radiologic evidence of liver metastases showed uptake of 131I-F(ab')2 in the metastases, as observed by single-photon-emission tomography. The only toxicity was hematologic, and no severe aplasia was observed when up to 250 mCi was infused. At the 300-mCi dose, 5 out of 6 patients presented grade-3 or -4 hematologic toxicity, with a nadir for neutrophils and thrombocytes ranging from 25 to 35 days after infusion. In these 5 cases, bone marrow was re-infused. No clinical complications were observed during aplasia. The tumor response could be evaluated in 9 out of 10 patients. One patient showed a partial response of one small liver metastasis (2 cm in diameter) and a stable evolution of the other metastases, 2 patients had stable disease, and 6 showed tumor progression at the time of evaluation (2 or 3 months after injection) by CT scan. This phase-I/II study demonstrated that a dose of 300 mCi of 131I-F(ab')2 from the anti-CEA Mab F6 is well tolerated with bone-marrow rescue, whereas a dose of 200 mCi can be infused without severe bone-marrow toxicity.

Increased flow of fatty acids toward beta-oxidation in developing seeds of Arabidopsis deficient in diacylglycerol acyltransferase activity or synthesizing medium-chain-length fatty acids.

Synthesis of polyhydroxyalkanoates (PHAs) from intermediates of fatty acid beta-oxidation was used as a tool to study fatty acid degradation in developing seeds of Arabidopsis. Transgenic plants expressing a peroxisomal PHA synthase under the control of a napin promoter accumulated PHA in developing seeds to a final level of 0. 06 mg g(-1) dry weight. In plants co-expressing a plastidial acyl-acyl carrier protein thioesterase from Cuphea lanceolata and a peroxisomal PHA synthase, approximately 18-fold more PHA accumulated in developing seeds. The proportion of 3-hydroxydecanoic acid monomer in the PHA was strongly increased, indicating a large flow of capric acid toward beta-oxidation. Furthermore, expression of the peroxisomal PHA synthase in an Arabidopsis mutant deficient in the enzyme diacylglycerol acyltransferase resulted in a 10-fold increase in PHA accumulation in developing seeds. These data indicate that plants can respond to the inadequate incorporation of fatty acids into triacylglycerides by recycling the fatty acids via beta-oxidation and that a considerable flow toward beta-oxidation can occur even in a plant tissue primarily devoted to the accumulation of storage lipids.

Molecular mechanisms for the transcriptional regulation of the Connexin36 gene expression in insulin-secreting cells

Résumé Régulation de l'expression de la Connexin36 dans les cellules sécrétrices d'insuline La communication intercellulaire est en partie assurée via des jonctions communicantes de type "gap". Dans la cellule ß pancréatique, plusieurs observations indiquent que le couplage assuré par des jonctions gap formées parla Connexine36 (Cx36) est impliqué dans le contrôle de la sécrétion de l'insuline. De plus, nous avons récemment démontré qu'un niveau précis d'expression de la Cx36 est nécessaire pour maintenir une bonne coordination de l'ensemble des cellules ß, et permettre ainsi une sécrétion synchrone et contrôlée d'insuline. Le développement du diabète et du syndrome métabolique est partiellement dû à une altération de la capacité des cellules ß à sécréter de l'insuline en réponse à une augmentation de la glycémie. Cette altération est en partie causée par l'augmentation prolongée des taux circulant de glucose, mais aussi de lipides, sous la forme d'acides gras libres, et de LDL (Low Density Lipoproteins), particules assurant le transport des acides gras et du cholestérol dans le sang. Nous avons étudié la régulation de l'expression de la Cx36 dans différentes conditions reflétant la physiopathologie du diabète de type 2 et du syndrome métabolique et démontré qu'une exposition prolongée à des concentrations élevées de glucose, de LDL, ainsi que de palmitate (acide gras saturé le plus abondant dans l'organisme), inhibent l'expression de la Cx36 dans les cellules ß. Cette inhibition implique l'activation de la PKA (Proteine Kinase A), qui stimule à son tour l'expression du facteur de transcription ICER-1 (Inductible cAMP Early Repressor-1). Ce puissant répresseur se fixe spécifiquement sur un motif CRE (cAMP Response Element), situé dans le promoteur du gène de la Cx36, inhibant ainsi son expression. Nous avons de plus démontré que des cytokines pro-inflammatoires, qui pourraient contribuer au développement du diabète, inhibent également l'expression de la Cx36. Cependant, les cytokines agissent indépendamment du répresseur ICER-1, mais selon un mécanisme requérant l'activation de l'AMPK (AMP dependant protein kinase). Sachant qu'un contrôle précis des niveaux d'expression de la Cx36 est un élément déterminant pour une sécrétion optimale de l'insuline, nos résultats suggèrent que la Cx36 pourrait être impliquée dans l'altération de la sécrétion de l'insuline contribuant à l'apparition du diabète de type 2. Summary A particular way by which cells communicate with each other is mediated by gap junctions, transmembrane structures providing a direct pathway for the diffusion of small molecules between adjacent cells. Gap junctional communication is required to maintain a proper functioning of insulin-secreting ß-cells. Moreover, the expression levels of connexin36 (Cx36), the sole gap junction protein expressed in ß-cells, are critical in maintaining glucose-stimulated insulin secretion. Chronic hyperglycemia and hyperlipidemia exert deleterious effects on insulin secretion and may contribute to the progressive ß-cell failure linked to the development of type 2 diabetes and metabolic syndrome. Since modulations of the Cx36 levels might impair ß-cell function, the general aim of this work was to elucidate wether elevated levels of glucose and lipids affect Cx36 expression. The first part of this work was dedicated to the study of the effect of high glucose concentrations on Cx36 expression. We demonstrated that glucose transcriptionally down-regulates the expression of Cx36 in insulin-secreting cells through activation of the protein kinase A (PKA), which in turn stimulates the expression of the inducible cAMP early repressor-1 (ICER-1). This repressor binds to a highly conserved cAMP response element (CRE) located in the Cx36 promoter, thereby inhibiting Cx36 expression. The second part of this thesis consisted in studying the effects of sustained exposure to free fatty acids (FFA) and human lipoproteins on Cx36 levels. The experiments revealed that the most abundant FFA, palmitate, as well as the atherogenic low density lipoproteins (LDL), also stimulate ICER-1 expression, resulting in Cx36 down-regulation. Finally, the third part of the work focused on the consequences of long-term exposure to proinflammatory cytokines on Cx36 content. Interleukin-1 ß (IL-1 ß) inhibits Cx36 expression and its effect is potentialized by tumor necrosis factor α (TNFα) and interferon γ (IFNγ). We further unveiled that the cytokines effect on Cx36 levels requires activation of the AMP dependent protein kinase (AMPK). Prolonged exposures to glucose, palmitate, LDL, and pro-inflammatory cytokines have all been proposed to contribute to the development of diabetes and metabolic syndrome. Since Cx36 expression levels are critical to maintain ß-cell function, Cx36 down-regulation by glucose, lipids, and cytokines might participate to the ß-cell failure associated with diabetes development.

Effects of four-week high-fructose diet on gene expression in skeletal muscle of healthy men.

AIMS: A high-fructose diet (HFrD) may play a role in the obesity and metabolic disorders epidemic. In rodents, HFrD leads to insulin resistance and ectopic lipid deposition. In healthy humans, a four-week HFrD alters lipid homoeostasis, but does not affect insulin sensitivity or intramyocellular lipids (IMCL). The aim of this study was to investigate whether fructose may induce early molecular changes in skeletal muscle prior to the development of whole-body insulin resistance. METHODS: Muscle biopsies were taken from five healthy men who had participated in a previous four-week HFrD study, during which insulin sensitivity (hyperinsulinaemic euglycaemic clamp), and intrahepatocellular lipids and IMCL were assessed before and after HFrD. The mRNA concentrations of 16 genes involved in lipid and carbohydrate metabolism were quantified before and after HFrD by real-time quantitative PCR. RESULTS: HFrD significantly (P<0.05) increased stearoyl-CoA desaturase-1 (SCD-1) (+50%). Glucose transporter-4 (GLUT-4) decreased by 27% and acetyl-CoA carboxylase-2 decreased by 48%. A trend toward decreased peroxisomal proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) was observed (-26%, P=0.06). All other genes showed no significant changes. CONCLUSION: HFrD led to alterations of SCD-1, GLUT-4 and PGC-1alpha, which may be early markers of insulin resistance.

Advances in tissue section preparation for MALDI imaging MS

Enriched by a decade of remarkable developments, matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) has witnessed a phenomenal expansion. Initially introduced for the mapping of peptides and intact proteins from mammalian tissue sections, MALDI IMS applications now extend to a wide range of molecules including peptides, lipids, metabolites and xenobiotics. Technology and methodology are quickly evolving to push the limits of the technique forward. Within a short period of time, numerous protocols and concepts have been developed and introduced in tissue section preparation, nonexhaustively including in situ tissue chemistries and solvent-free matrix depositions. Considering the past progress and current capabilities, this Review aims to cover the different aspects and challenges of tissue section preparation for MALDI IMS.

Central and peripheral metabolic changes induced by gamma-hydroxybutyrate.

STUDY OBJECTIVES: Gamma-hydroxybutyrate (GHB) was originally introduced as an anesthetic but was first abused by bodybuilders and then became a recreational or club drug.1 Sodium salt of GHB is currently used for the treatment of cataplexy in patients with narcolepsy. The mode of action and metabolism of GHB is not well understood. GHB stimulates growth hormone release in humans and induces weight loss in treated patients, suggesting an unexplored metabolic effect. In different experiments the effect of GHB administration on central (cerebral cortex) and peripheral (liver) biochemical processes involved in the metabolism of the drug, as well as the effects of the drug on metabolism, were evaluated in mice. DESIGN: C57BL/6J, gamma-aminobutyric acid B (GABAB) knockout and obese (ob/ob) mice were acutely or chronically treated with GHB at 300 mg/kg. MEASUREMENTS AND RESULTS: Respiratory ratio decreased under GHB treatment, independent of food intake, suggesting a shift in energy substrate from carbohydrates to lipids. GHB-treated C57BL/6J and GABAB null mice but not ob/ob mice gained less weight than matched controls. GHB dramatically increased the corticosterone level but did not affect growth hormone or prolactin. Metabolome profiling showed that an acute high dose of GHB did not increase the brain GABA level. In the brain and the liver, GHB was metabolized into succinic semialdehyde by hydroxyacid-oxoacid transhydrogenase. Chronic administration decreased glutamate, s-adenosylhomocysteine, and oxidized gluthathione, and increased omega-3 fatty acids. CONCLUSIONS: Our findings indicate large central and peripheral metabolic changes induced by GHB with important relevance to its therapeutic use.

Adjuvant radioimmunotherapy trial with iodine-131-labeled anti-carcinoembryonic antigen monoclonal antibody F6 F(ab')2 after resection of liver metastases from colorectal cancer.

PURPOSE: To evaluate the feasibility of radioimmunotherapy (RIT) with radiolabeled anti-carcinoembryonic antigen antibodies after complete resection of liver metastases (LM) from colorectal cancer. Patients and Methods: Twenty-two patients planned for surgery of one to four LM received a preoperative diagnostic dose of a 131I-F(ab')2-labeled anti-carcinoembryonic antigen monoclonal antibody F6 (8-10 mCi/5 mg). 131I-F(ab')2 uptake was analyzed using direct radioactivity counting, and tumor-to-normal liver ratios were recorded. Ten patients with tumor-to-normal liver ratios of >5 and three others were treated with a therapeutic injection [180-200 mCi 131I/50 mg F(ab')2] 30 to 64 days after surgery. RESULTS: Median 131I-F(ab')2 immunoreactivity in patient serum remained at 91% of initial values for up to 96 hours after injection. The main and dose-limiting-toxicity was hematologic, with 92% and 85% grades 3 to 4 neutropenia and thrombocytopenia, respectively. Complete spontaneous recovery occurred in all patients. No human anti-mouse antibody response was observed after the diagnosis dose; however, 10 of the 13 treated patients developed human anti-mouse antibody approximately 3 months later. Two treated patients presented extrahepatic metastases at the time of RIT (one bone and one abdominal node) and two relapsed within 3 months of RIT (one in the lung and the other in the liver). Two patients are still alive, and one of these is disease-free at 93 months after resection. At a median follow-up of 127 months, the median disease-free survival is 12 months and the median overall survival is 50 months. CONCLUSION: RIT is feasible in an adjuvant setting after complete resection of LM from colorectal cancer and should be considered for future trials, possibly in combination with chemotherapy, because of the generally poor prognosis of these patients.

Proline- and acidic amino acid-rich basic leucine zipper proteins modulate peroxisome proliferator-activated receptor alpha (PPAR alpha) activity.

In mammals, many aspects of metabolism are under circadian control. At least in part, this regulation is achieved by core-clock or clock-controlled transcription factors whose abundance and/or activity oscillate during the day. The clock-controlled proline- and acidic amino acid-rich domain basic leucine zipper proteins D-site-binding protein, thyrotroph embryonic factor, and hepatic leukemia factor have previously been shown to participate in the circadian control of xenobiotic detoxification in liver and other peripheral organs. Here we present genetic and biochemical evidence that the three proline- and acidic amino acid-rich basic leucine zipper proteins also play a key role in circadian lipid metabolism by influencing the rhythmic expression and activity of the nuclear receptor peroxisome proliferator-activated receptor α (PPARα). Our results suggest that, in liver, D-site-binding protein, hepatic leukemia factor, and thyrotroph embryonic factor contribute to the circadian transcription of genes specifying acyl-CoA thioesterases, leading to a cyclic release of fatty acids from thioesters. In turn, the fatty acids act as ligands for PPARα, and the activated PPARα receptor then stimulates the transcription of genes encoding proteins involved in the uptake and/or metabolism of lipids, cholesterol, and glucose metabolism.

Drainage of fluorescent liposomes from the vitreous to cervical lymph nodes via conjunctival lymphatics.

The use of liposomes as carriers for the delivery of biologically active molecules into the eye is of major interest. Indeed, encapsulation of biologically active molecules in liposomes may increase their bioavailability and may induce a sustained release, thus avoiding repeated intraocular injections and reducing side effects. We describe here the fate of rhodamine-conjugated liposomes (Rh-Lip) injected into the vitreous of normal Lewis rats. Twenty-four hours after intravitreal injection fluorescent liposomes were detected in the vitreous, the inner layer of the retina and to a lesser extent in the anterior segment of the eye. In addition, numerous Rh-Lip were also observed in the episclera and conjunctival stroma, in conjunctival lymphatic vessels and cervical lymph nodes (LN) draining the conjunctiva and the eye. In the LN, Rh-Lip were taken up by resident macrophages adjacent to CD4+ and CD8+ T cells. Thus, intravitreal injection of anti-inflammatory drugs loaded in liposomes could modulate the ocular immune microenvironment. In addition the passage of drugs into the cervical LN could alter the immune status of these LN and contribute to the regulation of intraocular inflammation. Our results suggest that this phenomenon should be taken into account to design new therapies based on intraocular drug administration.

Sensing of glucose in the brain.

The brain, and in particular the hypothalamus and brainstem, have been recognized for decades as important centers for the homeostatic control of feeding, energy expenditure, and glucose homeostasis. These structures contain neurons and neuronal circuits that may be directly or indirectly activated or inhibited by glucose, lipids, or amino acids. The detection by neurons of these nutrient cues may become deregulated, and possibly cause metabolic diseases such as obesity and diabetes. Thus, there is a major interest in identifying these neurons, how they respond to nutrients, the neuronal circuits they form, and the physiological function they control. Here I will review some aspects of glucose sensing by the brain. The brain is responsive to both hyperglycemia and hypoglycemia, and the glucose sensing cells involved are distributed in several anatomical sites that are connected to each other. These eventually control the activity of the sympathetic or parasympathetic nervous system, which regulates the function of peripheral organs such as liver, white and brown fat, muscle, and pancreatic islets alpha and beta cells. There is now evidence for an extreme diversity in the sensing mechanisms used, and these will be reviewed.

SCAP is required for timely and proper myelin membrane synthesis.

Myelination requires a massive increase in glial cell membrane synthesis. Here, we demonstrate that the acute phase of myelin lipid synthesis is regulated by sterol regulatory element-binding protein (SREBP) cleavage activation protein (SCAP), an activator of SREBPs. Deletion of SCAP in Schwann cells led to a loss of SREBP-mediated gene expression involving cholesterol and fatty acid synthesis. Schwann cell SCAP mutant mice show congenital hypomyelination and abnormal gait. Interestingly, aging SCAP mutant mice showed partial regain of function; they exhibited improved gait and produced small amounts of myelin indicating a slow SCAP-independent uptake of external lipids. Accordingly, extracellular lipoproteins partially rescued myelination by SCAP mutant Schwann cells. However, SCAP mutant myelin never reached normal thickness and had biophysical abnormalities concordant with abnormal lipid composition. These data demonstrate that SCAP-mediated regulation of glial lipogenesis is key to the proper synthesis of myelin membrane, and provide insight into abnormal Schwann cell function under conditions affecting lipid metabolism.

Comparison of copper-67- and iodine-125-labeled anti-CEA monoclonal antibody biodistribution in patients with colorectal tumors.

Copper-67 has comparable beta-particle emissions to that of 131I, but it displays more favorable gamma emission characteristics for application in radioimmunotherapy (RIT). This study investigates the potential of 67Cu-labeled monoclonal antibody (MAb) 35 for RIT of colorectal carcinoma. METHODS: Biokinetics of simultaneously injected 67Cu- and 125I-labeled MAb35 were studied in six patients scheduled for surgery of primary colorectal cancer. RESULTS: Whole-body clearance (T 1/2) of 67Cu, estimated from sequential anterior and posterior whole-body scans and corrected for decay of 67Cu, was 41 hr. Serum clearance of 67Cu was faster (27.41 hr) than that of 125I (38.33 hr). Mean tumor uptake of the 67Cu-labeled compound (0.0133% ID/g) exceeded that of 125I (0.0095% ID/g), and tumor-to-blood ratios were higher for 67Cu than for 125I, with averages of 6.07 and 2.41, respectively. The average 67Cu/125I ratio was 1.9 for tumor uptake, 0.7 for blood and 2.6 for tumor-to-blood ratios. Nonspecific liver uptake of 67Cu as calculated from whole-body scans was high in four patients, up to 25% of residual whole-body activity at 48 hr, but did not increase with time. We also observed some nonspecific bowel activity, as well as moderate to high uptake in benign polyps. CONCLUSION: Copper-67-labeled MAb35 is more favorable than its radioiodine-labeled counterpart for RIT of colorectal carcinoma due to higher tumor-to-blood ratios, but the problem of nonspecific liver and bowel uptake must first be overcome. The absolute accumulation of activity in tumor remains low, however, so the probability of cure with this compound alone is questionable. The use of 67Cu as one component of a multimodality adjuvant treatment seems to remain the most appropriate application for RIT.

Biochemical analysis of female mice urine with reference to endocrine function: a key tool for estrus detection.

Species-specific chemical signals released through urine, sweat, saliva and feces are involved in communication between animals. Urinary biochemical constituents along with pheromones may contribute to variation across reproductive cycles and facilitate to estrus detection. Hence, the present study was designed to analyze such biochemical profiles, such as proteins, carbohydrates, lipids, fatty acids, in response with steroid hormones such as estradiol and progesterone. The experimental groups were normal, prepubertal, ovariectomized, and ovariectomized with estrogentreated female mice. In normal mice, the protein and lipid concentrations in urine were significantly higher in proestrus and estrus phases and the quantity of fatty acids was also comparatively higher in estrus. Furthermore, certain fatty acids, namely tridecanoic, palmitic and oleic acids, were present during proestrus and estrus phases, but were exclusively absent in ovariectomized mice. However, the carbohydrate level was equally maintained throughout the four phases of estrous cycle. For successful communication, higher concentrations of protein and specific fatty acids in estrus are directly involved. The significant increase in estradiol at estrus and progesterone at metestrus seems to be of greater importance in the expression pattern of biochemical constituents and may play a notable role in estrous cycle regulation. Thus, we conclude that the variations observed in the concentration of the biochemical constituents depend on the phase of the reproductive cycle as well as hormonal status of animals. The appearance of protein and specific fatty acids during estrus phase raises the possibility to use these as a urinary indicators for estrus detection.

Interest of qualitative and quantitative profiling of endocannabinoids for evaluation of their implication in drug addiction process

Introduction: In the middle of the 90's, the discovery of endogenous ligands for cannabinoid receptors opened a new era in this research field. Amides and esters of arachidonic acid have been identified as these endogenous ligands. Arachidonoylethanolamide (anandamide or AEA) and 2-Arachidonoylglycerol (2-AG) seem to be the most important of these lipid messengers. In addition, virodhamine (VA), noladin ether (2-AGE), and N-arachidonoyl dopamine (NADA) have been shown to bind to CB receptors with varying affinities. During recent years, it has become more evident that the EC system is part of fundamental regulatory mechanisms in many physiological processes such as stress and anxiety responses, depression, anorexia and bulimia, schizophrenia disorders, neuroprotection, Parkinson disease, anti-proliferative effects on cancer cells, drug addiction, and atherosclerosis. Aims: This work presents the problematic of EC analysis and the input of Information Dependant Acquisition based on hybrid triple quadrupole linear ion trap (QqQLIT) system for the profiling of these lipid mediators. Methods: The method was developed on a LC Ultimate 3000 series (Dionex, Sunnyvale, CA, USA) coupled to a QTrap 4000 system (Applied biosystems, Concord, ON, Canada). The ECs were separated on an XTerra C18 MS column (50 × 3.0 mm i.d., 3.5 μm) with a 5 min gradient elution. For confirmatory analysis, an information-dependant acquisition experiment was performed with selected reaction monitoring (SRM) as survey scan and enhanced produced ion (EPI) as dependant scan. Results: The assay was found to be linear in the concentration range of 0.1-5 ng/mL for AEA, 0.3-5 ng/mL for VA, 2-AGE, and NADA and 1-20 ng/mL for 2-AG using 0.5 mL of plasma. Repeatability and intermediate precision were found less than 15% over the tested concentration ranges. Under non-pathophysiological conditions, only AEA and 2-AG were actually detected in plasma with concentration ranges going from 104 to 537 pg/mL and from 2160 to 3990 pg/mL respectively. We have particularly focused our scopes on the evaluation of EC level changes in biological matrices through drug addiction and atherosclerosis processes. We will present preliminary data obtained during pilot study after administration of cannabis on human patients. Conclusion: ECs have been shown to play a key role in regulation of many pathophysiological processes. Medical research in these different fields continues to growth in order to understand and to highlight the predominant role of EC in the CNS and peripheral tissues signalisation. The profiling of these lipids needs to develop rapid, highly sensitive and selective analytical methods.