Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting approximately 1% of the population older than 60 years. Classically, PD is considered to be a motor system disease and its diagnosis is based on the presence of a set of cardinal motor signs that are consequence of a pronounced death of dopaminergic neurons in the substantia nigra pars compacta (SNc). Nowadays there is considerable evidence showing that non-dopaminergic degeneration also occurs in other brain areas which seems to be responsible for the deficits in olfactory, emotional and memory functions that precede the classical motor symptoms in PD. Dopamine-replacement therapy has dominated the treatment of PD and although the currently approved antiparkinsonian agents offer effective relief of the motor deficits, they have not been found to alleviate the non-motor features as well as the underlying dopaminergic neuron degeneration and thus drug efficacy is gradually lost. Another major limitation of chronic dopaminergic therapy is the numerous adverse effects such as dyskinesias, psychosis and behavioral disturbance. The development of new therapies in PD depends on the existence of representative animal models to facilitate the evaluation of new pharmacological agents before they are applied in clinical trials. We have recently proposed a new experimental model of PD consisting of a single intranasal (i.n.) administration of the proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 1 mg/nostril) in rodents. Our findings demonstrated that rats and mice treated intranasally with MPTP suffer impairments in olfactory, cognitive, emotional and motor functions conceivably analogous to those observed during different stages of PD. Such infusion causes time-dependent loss of tyrosine hydroxylase in the olfactory bulb and SNc, resulting in significant dopamine depletion in different brain areas. We have also identified some pathogenic mechanisms possibly involved in the neurodegeneration induced by i.n. administration of MPTP including mitochondrial dysfunction, oxidative stress, activation of apoptotic cell death mechanisms and glutamatergic excitotoxicity. Therefore, the present review attempts to provide a comprehensive picture of the i.n. MPTP model and to highlight recent findings from our group showing its potential as a valuable rodent model for testing novel drugs that may provide alternative or adjunctive treatment for both motor and non-motor symptoms relief with a reduced side-effect profile as well as the discovery of compounds to modify the course of PD.
Pyrrolo[2,1-f][1,2,4]triazine template, a unique bridgehead nitrogen heterocycle, certainly deserves the title of "privileged scaffold" in the drug discovery field because of the versatility and potential to yield derivatives with a wide range of biological activities, such as anti-anaplastic lymphoma kinase (ALK), Janus kinase 2 (JAK2), VEGFR-2, EGFR and/or HER2, Met kinase, p38α mitogen-activated protein (MAP) kinase and insulin-like growth factor receptor (IGF-1R) kinase activities, etc. These different biological properties of pyrrolo[2,1-f][1,2,4]triazine derivatives have motivated new studies in searching for novel derivatives with improved activity and also other applications in pharmaceutical field. However, no systematic review is available in the literature on the pyrrolo[2,1-f][1,2,4]triazine derivatives concerning the design of potent drug-like compounds. Owing to the importance of this heterocyclic system, the present paper is an attempt to the pharmacological activities, structural modifications and the structure-activity relationship (SAR) reported for bridgehead nitrogen heterocycles in the current literature, making an effort to highlight the importance and therapeutic potentials of the pyrrolo[2,1-f][1,2,4]triazine scaffold and its bridgehead nitrogen bioisosters as heterocyclic privileged medicinal scaffolds.
Neutrophil elastase, a serine proteinase from the chymotrypsin family, has been the object of comprehensive experimental and theoretical studies to develop efficient human neutrophil elastase inhibitors. The serine protease has been linked to the pathology of a variety of inflammatory diseases, making it an attractive target for the development of anti-inflammatory compounds. In this work, we have built a common binding model of the 2-pyridin-3-yl-benzo[d][1,3]oxazin-4-one derivatives into the human neutrophil elastase binding site. This was accomplished through a comparative conformational analysis (using OMEGA, HYPERCHEM, and MOPAC software) of 2-pyridin-3-yl-benzo[d][1,3]oxazin-4-one inhibitors followed by rigid and flexible molecular docking (by the FRED and GLIDE programs) into the target protein. We conclude that OMEGA software generates the most representative conformers to model the protein-ligand interactions.
The homodimeric flavoenzyme glutathione reductase catalyzes NADPH-dependent glutathione disulfide reduction. This reaction is important for keeping the redox homeostasis in human cells and in the human pathogen Plasmodium falciparum. Different types of NADPH-dependent disulfide reductase inhibitors were designed in various chemical series to evaluate the impact of each inhibition mode on the propagation of the parasites. Against malaria parasites in cultures the most potent and specific effects were observed for redox-active agents acting as subversive substrates for both glutathione reductases of the Plasmodium-infected red blood cells. In their oxidized form, these redox-active compounds are reduced by NADPH-dependent flavoenzyme-catalyzed reactions in the cytosol of infected erythrocytes. In their reduced forms, these compounds can reduce molecular oxygen to reactive oxygen species, or reduce oxidants like methemoglobin, the major nutrient of the parasite, to indigestible hemoglobin. Furthermore, studies on a fluorinated suicide-substrate of the human glutathione reductase indicate that the glutathione reductase-catalyzed bioactivation of 3-benzylnaphthoquinones to the corresponding reduced 3-benzoyl metabolites is essential for the observed antimalarial activity. In conclusion, the antimalarial lead naphthoquinones are suggested to perturb the major redox equilibria of the targeted cells. These effects result in development arrest of the parasite and contribute to the removal of the parasitized erythrocytes by macrophages.
Multiple sclerosis (MS) is a progressive neurodegenerative disease affecting myelin and axons, which is perpetuated by autoreactive lymphocytes and other inflammatory cell types. Because of the multifactorial nature of this disease, therapies targeting a single process may not be sufficient to halt its progression. VIP and PACAP are two neuropeptides shown to regulate multiple aspects of innate and adaptive immunity, and can also act independently on neural cells to promote their survival and regeneration. Animal studies have proven the efficacy of these peptides for the treatment of several models of neural inflammatory disorders, including those which, like MS, have major Th1/Th17 components. In this review, the immunomodulatory actions of VIP and PACAP will be discussed, with particular emphasis on their potential significance in MS.
A variety of radiopharmaceuticals have been introduced for the internal therapy of malignant and inflammatory lesions in nuclear medicine. In order to destroy the diseased tissues radionuclides with high linear energy transfer (LET) such as beta, alpha, Auger or low energy conversion electron emitters are needed. The range of beta particles is in mm's so they are effective for large tumors. The range of alpha particles is short, only a few cell diameters. Thus, they are effective in treating circulating malignant cells and micrometastases. The range of Auger and conversion electrons is <0.1 micro m. They are very effective in cell killing when they are carried across cell membrane into the nucleus to damage DNA. Appropriate ions, molecules and particles are labelled with such radionuclides and used as radiopharmaceuticals in many different applications. For an effective dose to be delivered high target to non target ratios must be attained. Monoclonal antibodies to specific antigens expressed on tumor cells have been developed to increase the uptake by malignant tissues by specific accumulation. Radiolabelled peptides such as somatostatin, small molecules such as metaiodo-benzylguanidine (MIBG) and many different nano-and micro-particles have been investigated. The effectiveness of therapy can be increased by direct locoregional administration of the radiopharmaceutical. This way the radiation effects are confined locally and the normal tissues are spared from radiation effects. In this review article selection criteria and characteristics of radionuclides and carrier ions, molecules and particles for various therapeutic applications will be discussed, including mainly the recent developments.
It is well established that the metabolically active form of vitamin D, 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3) plays a key role in the establishment and maintenance of the calcium metabolism in the body. In addition to this classic effect of 1alpha,25(OH)2D3, substantial evidence has emerged demonstrating that 1alpha,25(OH)2D3 is able to regulate cell growth and differentiation in a number of different cell types, including cancer cells. However, the clinical usefulness of 1alpha,25(OH)2D3 is limited by its tendency to cause hypercalcaemia. Much effort has therefore been directed to identifying new vitamin D analogues with potent cell regulatory effects, but with weaker effects on the calcium metabolism than those of 1alpha,25(OH)2D3. One of these new synthetic analogues is Seocalcitol (EB 1089). Despite being 50-200 times more potent than 1alpha,25(OH)2D3 with respect to regulation of cell growth and differentiation in vitro as well as in vivo, EB 1089 displays a reduced calcaemic activity in vivo compared to that of 1alpha, 25(OH)2D3. These characteristics make EB 1089 a potentially useful compound for the treatment of cancer. Recent clinical evaluation of EB 1089 has focused mainly on establishing a maximum tolerated dose in cancer patients. Early results confirm that the low calcaemic activity observed in animals can be reproduced in the clinic. Furthermore, EB 1089 has been shown to induce regression of tumours, especially in hepatocellular carcinoma where complete remission has been obtained. In conclusion, the development of EB 1089 as an anti-cancer drug holds promise. However, its final evaluation must await the completion of ongoing controlled clinical trials.
A basic problem in the discovery and development of novel drugs to be used in the treatment of neurological and psychiatric disorders is the absence of relevant in vitro or in vivo animal models that can yield results which can be extrapolated to man. Drug research now benefits from the fast development of functional imaging techniques such as positron emission tomography (PET) which trace radiolabelled molecules directly in the human brain. PET uses molecules that are labelled with short-lived radionuclides and injected intravenously into experimental animals, human volunteers or patients. The most frequent approach is to study how an unlabelled drug inhibits specific binding of a well characterised selective PET radioligand. The alternative direct approach is to radiolabel a new potential drug and to trace its uptake, anatomical distribution and binding in brain. Furthermore, the effects of a novel drug on physiological-biochemical parameters, such as glucose metabolism or blood flow, can also be assessed. The demonstration of quantitative relationships between drug binding in vivo and drug effects in patients is used to validate targets for drug action, to correlate pharmacological and physiological effects, and to optimise clinical treatment.
The high level expression of somatostatin receptors (SSTR) on various tumor cells has provided the molecular basis for successful use of radiolabeled octreotide / lanreotide analogs as tumor tracers in nuclear medicine. Other (nontumoral) potential indications for SSTR scintigraphy are based on an increased lymphocyte binding at sites of inflammatory or immunologic diseases such as thyroid-associated ophthalmology. The vast majority of human tumors seem to over-express the one or the other of five distinct hSSTR subtype receptors. Whereas neuroendocrine tumors frequently overexpress hSSTR2, intestinal adenocarcinomas seem to overexpress more often hSSTR3 or hSSTR4, or both of these hSSTR. In contrast to In-DTPA-DPhe(1)-octreotide (OctreoScan(R)) which binds to hSSTR2 and 5 with high affinity (Kd 0.1-5 nM), to hSSTR3 with moderate affinity (K(d) 10-100 nM) and does not bind to hSSTR1 and hSSTR4, (111)In / (90)Y-DOTA-lanreotide was found to bind to hSSTR2, 3, 4, and 5 with high affinity, and to hSSTR1 with lower affinity (K(d) 200 nM). Based on its unique hSSTR binding profile, (111)In-DOTA-lanreotide was suggested to be a potential radioligand for tumor diagnosis, and (90)Y-DOTA-lanreotide suitable for receptor-mediated radionuclide therapy. As opposed to (111)In-DTPA-DPhe(1)-octreotide and (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide, discrepancies in the scintigraphic results were seen in about one third of (neuroendocrine) tumor patients concerning both the tumor uptake as well as detection of tumor lesions. On a molecular level, these discrepancies seem to be based on a "higherrdquuo; high-affinity binding of (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide to hSSTR2 (K(d) 0.1-1 nM). Other somatostatin analogs with divergent affinity to the five known hSSTR subtype receptors have also found their way into the clinics, such as (99m)Tc-depreotide (NeoSpect(R); NeoTect(R)). Most of the imaging results are reported for neuroendocrine tumors (octreotide analogs) or nonsmall cell lung cancer ((99m)Tc-depreotide), indicating high diagnostic cabability of this type of receptor tracers. Consequently to their use as receptor imaging agents, hSSTR recognizing radioligands have also been implemented for experimental receptor-targeted radionuclide therapy. Beneficial results were reported for high-dose treatment with (111)In-DTPA-DPhe(1)-octreotide, based on the emission of Auger electrons. The Phase IIa study "MAURITIUS" (Multicenter Analysis of a Universal Receptor Imaging and Treatment Initiative, a eUropean Study) showed in progressive cancer patients (therapy entry criteria) with a calculated tumor dose > 10 Gy / GBq (90)Y-DOTA-lanreotide, the proof-of-principle for treating tumor patients with peptide receptor imaging agents. In the "MAURITIUS" study, cummulative treatment doses up to 200 mCi (90)Y-DOTA-lanreotide were given as short-term infusion. Overall treatment results in 70 patients indicated stable tumor disease in 35% of patients and regressive tumor disease in 10% of tumor patients with different tumor entities expressing hSSTR. No acute or chronic severe hematological toxicity, change in renal or liver function parameters due to (90)Y-DOTA-lanreotide treatment, were reported. (90)Y-DOTA-DPhe(1)-Tyr(3)-octreotide may show a higher tumor uptake in neuroendocrine tumor lesions and may therefore be superior for treatment in patients with neuroendocrine tumors. However, there is only limited excess to long-term and survival data at present. Potential indications for (90Y-DOTA-lanreotide are radioiodine-negative thyroid cancer, hepatocellular cancer and lung cancer. Besides newer approaches and recent developments of 188)Re-labeled radioligands, no clinical results on the treatment response are yet available. In conclusion, several radioligands have been implemented on the basis of peptide receptor recognition throughout the last decade. A plentitude of preclinical data and clinical studies confirm their potential use in diagnosis as well as "proof-of-principle" for therapy of cancer patients. However, an optimal radiopeptide formulatioents. However, an optimal radiopeptide formulation does not yet exist for receptor-targeted radionuclide therapy. Ongoing developments may result in peptides more suitable for this kind of receptor-targeted radionuclide therapy.
Binge eating behavior has been noted in some eating disorders as well as in obesity. The goal of this paper is to review current, non-serotonergic pharmaceutical approaches to treat binge eating. Further, using information derived from preclinical models, we discuss candidate neurotransmitter systems for study as targets for the treatment of binge eating. Dopaminergic circuits have been implicated in both laboratory animal models and human studies of binge eating, though existing medications specifically targeting the dopaminergic system have been found to have adverse side effects. Opioidergic and gamma-aminobutyric acid (GABA) systems also appear to be highly involved in aspects of binge eating; further, opioid antagonists, such as naloxone and naltrexone, and GABA agonists, such as baclofen, have all been shown to be effective in treating alcohol dependence and may be equally efficacious in attenuating binge eating. Preclinical evidence, and some clinical evidence, suggests that cannabinoid antagonism may also be useful in the treatment of binge eating, although the specific effect of antagonists, on binge consumption remains unclear. Overall, each of these neurotransmitter systems provides a promising avenue for new pharmacotherapy development for binge eating, and preclinical and human studies provide a strong rationale for the development of highly-selective drugs that target this neurocircuitry.
The only bromine and iodine radioisotopes worth using in PET or SPECT in vivo investigations during the development of a new drug are 76Br and 123I. It is most of the time impossible to isotopically label a drug with 76Br or 123I since the occurrence of drugs having a bromine or an iodine atom within their chemical structure is quite limited. However, by using specific radiobrominated or radioiodinated probes, it is possible to study in vivo the potential interaction of a drug with biochemical processes such as blood flow, glucose consumption, protein synthesis or cell proliferation and neurotransmission. Radiobrominated and radioiodinated probes have been described mainly for assessing cell proliferation. For imaging various classes of specific binding sites involved in neuronal or hormonal transmission, a great number of radiohalogenated ligands have been proposed and validated. The two-steps strategy consists of performing an "in vivo assay" by using first of all, one of these specific radio-brominated/-iodinated ligands (or probes) for targeting specific binding sites (receptor, transporter, enzymes) and in a second step by assessing the interaction of the cold drug on the binding of these probes. This indirect observation of drug-receptor (transporter, enzyme) occupancy allows predicting response, optimum dose and optimum scheduling. The most important radiobrominated and radioiodinated ligands specific for dopaminergic, serotoninergic, cholinergic and gabaergic binding sites and their application in drug development processes are reviewed.
Arsenic trioxide (As2O3) has been demonstrated to suppress tumorigenesis in human glioma. However, the exact molecular mechanisms by which As2O3 exerts its tumor suppressor functions are elusive. Therefore, it is warranted to explore the underlying mechanism of As2O3-mediated anti-tumor activity in glioma.
To achieve our goal, we used multiple approaches including MTT assay, apoptosis, Real-time RT-PCR, Western blotting, invasion assay, and gene transfection.
We observed that A22O3 inhibited cell growth and induced apoptosis as well as suppressed migration and invasion in human glioma cells. Moreover, we found that As2O3 down-regulated miR-125b expression and subsequently up-regulated its target gene Bak1 expression. Furthermore, we identified that As2O3 exerts its anti-tumor activity partly through regulation of miR-125b.
Our present study suggests that As2O3 could be a potential therapeutic agent for treatment of human glioma.
The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) form a very effective barrier to the free diffusion of many polar solutes into the brain. Many metabolites that are polar have their brain entry facilitated by specific inwardly-directed transport mechanisms. In general the more lipid soluble a molecule or drug is, the more readily it will tend to partition into brain tissue. However, a very significant number of lipid soluble molecules, among them many useful therapeutic drugs have lower brain permeability than would be predicted from a determination of their lipid solubility. These molecules are substrates for the ABC efflux transporters which are present in the BBB and BCSB and the activity of these transporters very efficiently removes the drug from the CNS, thus limiting brain uptake. P-glycoprotein (Pgp) was the first of these ABC transporters to be described, followed by the multidrug resistance-associated proteins (MRP) and more recently breast cancer resistance protein (BCRP). All are expressed in the BBB and BCSFB and combine to reduce the brain penetration of many drugs. This phenomenon of "multidrug resistance" is a major hurdle when it comes to the delivery of therapeutics to the brain, not to mention the problem of cancer chemotherapy in general. Therefore, the development of strategies for bypassing the influence of these ABC transporters and for the design of effective drugs that are not substrates and the development of inhibitors for the ABC transporters becomes a high imperative for the pharmaceutical industry.
In recent years, VIP/PACAP/secretin family has special interest. Family members are vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP), secretin, glucagon, glucagon like peptide-1 (GLP(1)), GLP(2), gastric inhibitory peptide (GIP), growth hormone releasing hormone (GHRH or GRF), and peptide histidine methionine (PHM). Most of the family members present both in central nervous system (CNS) and in various peripheral tissues. The family members that are released into blood from periphery, especially gut, circulate the brain and they can cross the blood brain barrier. On the other hand, some of the members of this family that present in the brain, can cross from brain to blood and reach the peripheral targets. VIP, secretin, GLP(1), and PACAP 27 are transported into the brain by transmembrane diffusion, a non-saturable mechanism. However, uptake of PACAP 38 into the brain is saturable mechanism. While there is no report for the passage of GIP, GLP(2), and PHM, there is only one report that shows, glucagon and GHRH can cross the BBB. The passage of VIP/PACAP/secretin family members opens up new horizon for understanding of CNS effects of peripherally administrated peptides. There is much hope that those peptides may prove to be useful in the treatment of serious neurological diseases such as Alzheimer's disease, amyotropic lateral sclerosis, Parkinson's disease, AIDS related neuropathy, diabetic neuropathy, autism, stroke and nerve injury. Their benefits in various pathophysiologic conditions undoubtly motivate the development of a novel drug design for future therapeutics.
Recent progress in the development of inhibitors of human Type II s-PLA2 as potential anti-inflammatory agents is presented. While many companies have curtailed their efforts in the PLA2 area, Eli Lilly and Shionogi are continuing to advance LY-315920 (S-5920) as a potential treatment for sepsis and other diseases that have an inflammatory component. The Lilly developmental effort leading to LY-315920 is extensively reviewed, as well as the current status of other small molecular weight inhibitors of Type II s-PLA2 that have been reported to be in late-stage development
Here we have studied regulatory changes of μ-opioid receptors accompanying in vivo 14-methoxymetopon treatments of rats. Previously, this ligand has been shown to be an extremely potent, centrally acting μ-opioid specific analgesic with low physical dependence, tolerance, respiratory depression, constipation and other side effects. Our work shows that it is a highly potent full agonist of μ-opioid receptor coupled G-protein signaling in vitro, alike the well-known opioid agonist, etorphine. However, unlike etorphine, which desensitized and down-regulated the endogenous μ-opioid receptors, 14-methoxymetopon, given to rats intraperitoneally (i.p.) either acutely or chronically, did not change the binding or G-protein signaling of μ-opioid receptors in rat brain subcellular membranes. Thereby, these data provide further evidence that there is no direct relationship between the efficacy of the ligand in signaling and its ability to internalize or desensitize the receptor. Viewed collectively with published work, it is discussed that μ-opioid receptors display functional selectivity, also called 'biased agonism'. This concept implies that each ligand may induce unique, ligand-specific receptor conformation that can result in distinct agonist-directed trafficking and/or signal transduction pathways associated with the receptor. Ligand-specific signaling may open up new directions for designing potent analgesics that do not interact with unwanted signaling pathways, which mediate undesired side-effects, such as tolerance and dependence.
The well-known opioid agonists, oxycodone and oxymorphone, and the opioid antagonists, naloxone and naltrexone are commonly used clinical agents and research tools in the opioid field. They belong to the class of morphinan-6-ones, and produce their pharmacological effects by interacting with opioid receptors, i.e. mu (MOR), delta (DOR) and kappa (KOR). The search for potent agonists and antagonists has continuously engaged the interest of pharmaceutical research, aiming for the identification of safer therapeutic agents or discovery of opioids with novel therapeutic properties and with lesser unwanted side effects. The chemically highly versatile carbonyl group in position 6 of mophinan-6-ones permits functionalization and modification leading to numerous opioid ligands. We have focused on representative examples of various derivatives and interesting approaches for the development of structurally distinct molecules with substitution at C6 (e.g. 6-methylene, 6-hydroxy, 6-amido, bifunctional ligands), as preclinically and clinically valuable opioids. In this work, the development of 6-amino and 6-guanidino substituted 14-alkoxymorphinans, including the synthesis and pharmacological investigations is presented. The new approach represented by the introduction of amino and guanidino groups into position 6 of the morphinan skeleton of 14-O-methyloxymorphone, led to compounds with high efficacy, MOR affinity and selectivity, which act as potent antinociceptive agents. Altogether, as a consequence of target drug design and synthetic efforts in the field of morphinan-6-ones, we have achieved a better understanding of the function of the opioid system, and such efforts may open new avenues for further investigations.
Packaging small-molecule drugs into nanoparticles improves their bio-availability, bio-compatibility and safety profiles. Multifunctional particles carrying large drug payloads for targeted transport, immune evasion and favourable drug release kinetics at the target site, require a certain minimum size usually 30-300 nm diameter, so are nanoparticles. Targeting particles to a disease site can signal the presence of the disease site, block a function there, or deliver a drug to it. Targeted nanocarriers must navigate through blood-tissue barriers, varying in strength between organs and highest in the brain, to reach target cells. They must enter target cells to contact cytoplasmic targets; specific endocytotic and transcytotic transport mechanisms can be used as trojan horses to ferry nanoparticles across cellular barriers. Specific ligands to cell surface receptors, antibodies and antibody fragments, and aptamers can all access such transport mechanisms to ferry nanoparticles to their targets. The pharmacokinetics and pharmacodynamics of the targeted drug-bearing particle depend critically on particle size, chemistry, surface charge and other parameters. Particle types for targeting include liposomes, polymer and protein nanoparticles, dendrimers, carbon-based nanoparticles e.g. fullerenes, and others. Immunotargeting by use of monoclonal antibodies, chimeric antibodies and humanized antibodies has now reached the stage of clinical application. High-quality targeting groups are emerging: antibody engineering enables generation of human/like antibody (fragments) and facilitates the search for clinically relevant biomarkers; conjugation of nanocarriers to specific ligands and to aptamers enables specific targeting with improved clinical efficacy. Future developments depend on identification of clinically relevant targets and on raising targeting efficiency of the multifunctional nanocarriers.
We reviewed stable gastric pentadecapeptide BPC 157-NO-system-relation, its close participation in Moncada's (maintained vascular integrity, platelets control) homeostatic healing response of NO-system to injury. Namely, BPC 157 particular healing effect also affects all events after vascular integrity loss (dependent on circumstances, it reduces either thrombosis (abdominal aorta anastomosis) or bleeding/thrombocytopenia (amputation, heparin, warfarin, aspirin)) and in a series of different injurious models, acute and chronic, BPC 157 consistently advances healing after severe injuries in various tissues spontaneously unable to heal; stimulates egr-1 and naB2 genes; exhibits high safety (LD1 not achieved)). Hypothesis, that BPC 157 (since formed constitutively in the gastric mucosa, stable in human gastric juice, along with significance of NO-synthase and the basal formation of NO in stomach mucosa, greater than that seen in other tissues) exhibits a general, effective competing both with L-arginine analogues (i. e. , L-NAME) and L-arginine, and that this has some physiologic importance (NO-generation), later, practically supports its beneficial effects illustrating BPC 157 and NO-system mutual (with L-NAME/L-arginine; alone and together) relations in (i) gastric mucosa and mucosal protection, following alcohol lesions, in cytoprotection course, NO-generation, and blood pressure regulation; (ii) alcohol acute/chronic intoxication, and withdrawal; (iii) cardiovascular disturbances, chronic heart failure, pulmonary hypertension, and arrhythmias; (iv) disturbances after hypokalemia and hyperkalemia, and potassium-cell membrane dysfunction; and finally, in (v) complex healing failure, proved by the fistulas healing, colocutaneous and esophagocutaneous. However, how this advantage of modulating NO-system (i. e. , particular effect on eNOS gene), may be practically translated into an enhanced clinical performance remains to be determined.
Stable gastric pentadecapeptide BPC 157 is an anti-ulcer peptidergic agent, safe in inflammatory bowel disease clinical trials (GEPPPGKPADDAGLV, M.W. 1419, PL 14736) and wound healing, stable in human gastric juice and has no reported toxicity. We focused on BPC 157 as a therapy in peridontitis, esophagus, stomach, duodenum, intestine, liver and pancreas lesions. Particularly, it has a prominent effect on alcohol-lesions (i.e., acute, chronic) and NSAIDs-lesions (interestingly, BPC 157 both prevents and reverses adjuvant arthritis). In rat esophagitis and failed function of both lower esophageal sphincter (LES) and pyloric sphincters (PS), BPC 157 increased pressure in both sphincters till normal and reduced esophagitis. However, in healthy rats, it may decrease (PS) or increase (LES) the pressure in sphincters. It has strong angiogenic potential, it acts protectively on endothelium, prevents and reverses thrombus formation after abdominal aorta anastomosis, affects many central disturbances (i.e., dopamine and 5-HT system), the NO-system (either L-arginine and L-NAME effects), endothelin, acts as a free radical scavenger (counteracting CCl4-, paracetamol-, diclofenac-injuries) and exhibits neuroprotective properties. BPC 157 successfully heals the intestinal anastomosis, gastrocutaneous, duodenocutaneous and colocutaneous fistulas in rats, as well as interacting with the NO-system. Interestingly, the fistula closure was achieved even when the BPC 157 therapy was postponed for one month. In short-bowel syndrome escalating throughout 4 weeks, the constant weight gain above preoperative values started immediately with peroral and parental BPC 157 therapy and the villus height, crypth depth and muscle thickness (inner (circular) muscular layer) additionally increased. Thus, BPC 157 may improve gastrointestinal tract therapy.
This review focuses on the described effects of BPC 157 on blood vessels after different types of damage, and elucidates by investigating different aspects of vascular response to injury (endothelium damage, clotting, thrombosis, vasoconstriction, vasodilatation, vasculoneogenesis and edema formation) especially in connection to the healing processes. In this respect, BPC 157 was concluded to be the most potent angiomodulatory agent, acting through different vasoactive pathways and systems (e.g. NO, VEGF, FAK) and leading to optimization of the vascular response followed, as it has to be expected, by optimization of the healing process.
The significance of cytoprotection and adaptive cytoprotection and the peptides importance remained to be not completely determined. BPC 157 is an anti-ulcer peptidergic agent, proven in clinical trials to be both safe in inflammatory bowel disease (PL-10, PLD-116, PL 14736) and wound healing, and stable in human gastric juice, with no toxicity being reported. It has a prominent effect on alcohol- lesions (i.e., induced acutely and chronically) and non-steroidal anti-inflammatory drugs-lesions (while interestingly BPC 157 may both prevent and reverse adjuvant arthritis). To review the importance of BPC 157, this review focused on Robert's cytoprotection concept described in rat stomach, reviewing our evidence that may resolve whether the cytoprotection and adaptive cytoprotection is an uniform phenomenon or not; whether the phenomenon or phenomena are endogenous or not, depending on nature of the irritants (mild or strong); whether this may contribute to stomach mucosa defense either when threaten by various ulcerogens or afforded by various antiulcer agents; whether these phenomena are uniform in whole gastrointestinal tract or not; whether they are interrelated or not. Finally, the importance of the cytoprotection phenomena and cytoprotection activity for skin wound healing, and wound healing in general was challenged. Thereby, this review focused on BPC 157 role in cytoprotection and adaptative cytoprotection suggesting that it may be the essential endogenous mediator able to mediate both cytoprotective and adaptive cytoprotective response in stomach and the whole gastrointestinal tract with significant importance in wound healing as well.
Stable gastric pentadecapeptide BPC 157 is an anti-ulcer peptidergic agent, proven in clinical trials to be both safe in inflammatory bowel disease (PL-10, PLD-116, PL 14736) and wound healing, stable in human gastric juice, with no toxicity being reported. Recently, we claim that BPC 157 may be used as an antidote against NSAIDs. We focused on BPC 157 beneficial effects on stomach, duodenum, intestine, liver and brain injuries, adjuvant arthritis, pain, hyper/hypothermia, obstructive thrombus formation and thrombolysis, blood vessel function, counteraction of prolonged bleeding and thrombocytopenia after application of various anticoagulants and anti-platelet agents and wound healing improvement. The arguments for BPC 157 antidote activity (i.e., the role of BPC 157 in cytoprotection, being a novel mediator of Roberts cytoprotection and BPC 157 beneficial effects on NSAID mediated lesions in the gastrointestinal tract, liver and brain and finally, counteraction of aspirin-induced prolonged bleeding and thrombocytopenia) obviously have a counteracting effect on several established side-effects of NSAID use. The mentioned variety of the beneficial effects portrayed by BPC 157 may well be a foundation for establishing BPC 157 as a NSAID antidote since no other single agent has portrayed a similar array of effects. Unlike NSAIDs, a very high safety (no reported toxicity (LD1 could be not achieved)) profile is reported for BPC 157. Also, unlike the different dosage levels of aspirin, as a NSAID prototype, which differ by a factor of about ten, all these beneficial and counteracting effects of BPC 157 were obtained using the equipotent dosage (µg, ng/kg) in parenteral or peroral regimens.
Human laboratory studies have a rich history in the alcoholism field and several important determinants of alcohol use disorders have been successfully modeled under controlled laboratory conditions. Laboratory paradigms have been employed to identify biobehavioral risk markers for alcohol misuse and more recently, have been integrated with behavioral genetic, neuroimaging, and pharmacological approaches to further elucidate the neuropathophysiology of addiction and to screen for efficacious treatments. This review will address the rationale and application of human laboratory models to advance pharmacotherapy development for alcohol dependence. It is argued that when properly implemented, laboratory models may help scientists and clinicians understand mechanisms of pharmacotherapy response, which in turn may inform efforts to optimize the currently available and newly developed treatments for alcoholism. Limitations and future directions are discussed.
Schizophrenic patients exhibit debilitating impairments of intellectual function. Typical and atypical antipsychotic medications are largely ineffective at treating the cognitive deficits of schizophrenia (CDS), and efforts to discover compounds that treat these symptoms are ongoing. Considerable tobacco use in schizophrenic patients, genetic linkage, and receptor binding studies suggest the involvement of nicotinic acetylcholine receptors (nAChRs) in schizophrenia. Neuronal alpha4beta2 nAChRs are widely distributed in the mammalian brain, and are implicated in normal cognitive functioning in animal models. Ligands of various selectivity and potency have been used to study the role of the alpha4beta2 subtype in schizophrenia. For instance, studies in rodents show that alpha4beta2 agonists improve sensory gating, an information processing function that is deficient in schizophrenia. Pharmacological studies in animals also suggest that alpha4beta2 nAChRs are involved in other cognitive domains that are impaired in schizophrenia, including speed of processing, working memory, visual learning and memory, and social cognition. The non-selective nAChR agonist nicotine has been shown to improve CDS in several human clinical studies, and recent trials have been undertaken to evaluate the efficacy of more alpha4beta2 selective compounds. It remains to be determined whether alpha4beta2 agonists will provide greater efficacy than nicotine for CDS or reducing tobacco use in patients. Pre-clinical evidence to date suggests that agonists of the nicotinic alpha4beta2 subtype could be useful in improving cognitive function in schizophrenic patients.
Dengue viruses cause 50-100 million cases of acute febrile disease every year, including more than 500000 reported cases of the severe forms of the disease-dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Attempts to create conventional vaccines have been hampered by the lack of suitable experimental models, the need to provide protection against all four serotypes simultaneously and the possible involvement of virus-specific immune responses in severe disease. Live attenuated D2 16681-PDK53 vaccine was first developed from Mahidol University, Thailand. This vaccine induced both humoral and cell-mediated immunity and lack of reactogeneticity in humans. Infectious cDNA clones of the virulent D2 16681 virus and its attenuated D2 16681-PDK53 were constructed. The attenuated virus elicited neutralizing antibodies in mice and monkeys and developed viremia in monkeys. At molecular level, patterns of cytokines which are immunological mediators released from human mononuclear cells obtained from dengue naïve and immune donors infected with this attenuated virus compared with virulent virus were studied. In dengue naïve PBMC, the virulent and attenuated clones induced alternation in expression of 25 and 24 versus 13 and 18 genes out of 268 genes on day 1 and 3. In dengue immune PBMC, the virulent and attenuated clones induced alternation in expression of 33 and 38 versus 25 and 29 genes on days 1 and 3. Up-regulation of IL-1beta, IL-6, IL-8, IL-10, IFN-alpha, IFNgammaR, MIP-1alpha, MIP-1beta, MIP-2alpha, VEGF and down-regulation of IL-4, IL-4R, IL-RII, MIF, RANTES, IGF-1, GM-CSF-2 were shown. This review pointed out the infectious clones of the attenuated D2 16681-PDK53 was safe and induced both neutralizing antibodies in vivo and cytokine gene expression in vitro at molecular level. Furthermore, the phenotypic markers of ideal dengue vaccine could be included the alteration of cytokine gene expression and cytokine production in human mononuclear cells.
Colorectal cancer is one of the leading causes of cancer deaths in the Western world. More than 56,000 newly diagnosed colorectal cancer patients die each year in the United States. Available therapies are either not effective or have unwanted side effects. Epidemiological data suggest that dietary manipulations play an important role in the prevention of many human cancers. Curcumin the yellow pigment in turmeric has been widely used for centuries in the Asian countries without any toxic effects. Epidemiological data also suggest that curcumin may be responsible for the lower rate of colorectal cancer in these countries. Curcumin is a naturally occurring powerful anti-inflammatory medicine. The anticancer properties of curcumin have been shown in cultured cells and animal studies. Curcumin inhibits lipooxygenase activity and is a specific inhibitor of cyclooxygenase-2 expression. Curcumin inhibits the initiation of carcinogenesis by inhibiting the cytochrome P-450 enzyme activity and increasing the levels of glutathione-S-transferase. Curcumin inhibits the promotion/progression stages of carcinogenesis. The anti-tumor effect of curcumin has been attributed in part to the arrest of cancer cells in S, G2/M cell cycle phase and induction of apoptosis. Curcumin inhibits the growth of DNA mismatch repair defective colon cancer cells. Therefore, curcumin may have value as a safe chemotherapeutic agent for the treatment of tumors exhibiting DNA mismatch repair deficient and microsatellite instable phenotype. Curcumin should be considered as a safe, non-toxic and easy to use chemotherapeutic agent for colorectal cancers arise in the setting of chromosomal instability as well as microsatellite instability.
An emerging role of IL-17 in the inflammatory response associated with pathogenesis of neurodegeneration has been recently suggested. However, though diet represents a key factor in the modulation of inflammatory processes, evidence is not currently available on the nutritional regulation of IL-17 in humans. In a double blind, randomized, placebo controlled, crossover study, we investigated the effect of High Fat Meal (HFM) on IL-17 circulating levels in presence of a placebo (HFM-P) or with a Fruit Juice Drink (HFM-FJD) composed of pineapple, blackcurrant and plum in fourteen healthy overweight humans. Fasting in the morning subjects ingested a test meal providing 1344 Kcal. Ingestion of HFM-P induced an inflammatory response mediated by TNF-α (p < 0.001), IL-6 (p < 0.001) and IL-17 (p < 0.01). Plasma IL-17 concentration significantly increased at 1 h (+2.6 ± 1.1 pg/ml), remaining high at 4 h (+2.98 ± 1.2 pg/ml), 6 h (+2.38 ± 0.6 pg/ml) and 8 h (+2.8 ± 0.9 pg/ml) (ANOVA for time-course p=0.009). When the HFM was consumed in the presence of the FJD a marked inhibition of IL-17 response to the HFM was observed (ANOVA between treatment p=0.037). We provided, for the first time, evidence on the role of diet in modulating IL-17 production in healthy overweight subjects.
Restoring p53 activity by inhibiting the interaction between p53 and MDM2 represents an attractive approach for cancer therapy. To this end, a number of small-molecule p53-MDM2 binding inhibitors have been developed during the past several years. Nutlin-3 is a potent and selective small-molecule MDM2 antagonist that has shown considerable promise in pre-clinical studies. This review will highlight recent advances in the development of small-molecule MDM2 antagonists as potential cancer therapeutics, with special emphasis on Nutlin-3.
Brain cancer is a devastating disease. Despite extensive research, treatment of brain tumors has been largely ineffective and the diagnosis of brain cancer remains uniformly fatal. Failure of brain cancer treatment may be in part due to limitations in drug delivery, influenced by the ABC drug efflux transporters P-gp and BCRP at the blood-brain and blood-tumor barriers, in brain tumor cells, as well as in brain tumor stem-like cells. P-gp and BCRP limit various anti-cancer drugs from entering the brain and tumor tissues, thus rendering chemotherapy ineffective. To overcome this obstacle, two strategies - targeting transporter regulation and direct transporter inhibition - have been proposed. In this review, we focus on these strategies. We first introduce the latest findings on signaling pathways that could potentially be targeted to down-regulate P-gp and BCRP expression and/or transport activity. We then highlight in detail the new paradigm of P-gp and BCRP working as a "cooperative team of gatekeepers" at the blood-brain barrier, discuss its ramifications for brain cancer therapy, and summarize the latest findings on dual P-gp/BCRP inhibitors. Finally, we provide a brief summary with conclusions and outline the perspectives for future research endeavors in this field.
Prostate cancer (PCa) is now the most prevalent cancer in men in the U.S.A. and Europe. At present the major treatment options include surgical or medical castration. These strategies depend on the abolition of the production of testosterone by the testes. However, as these procedures do not affect adrenal androgen production, they are frequently combined with androgen receptor antagonist to block their action. Inhibition of the key enzyme which catalyzes the biosynthesis of androgens from pregnane precursors, 17alpha-hydroxylase/17,20-lyase (hereafter referred to as CYP17 ) could prevent androgen biosynthesis from both sources. Thus total blockade of androgen production by CYP17 inhibitors may provide effective treatment of prostate cancer patients. Indeed, this strategy is now an area of intense interest within research institutions and the pharmaceutical industry. This review highlights development in the design and evaluation of both steroidal and non-steroidal CYP17 inhibitors since 1965. Major emphasis is given to the potent CYP17 inhibitors and those which may show clinical promise. The review could function as a comprehensive working reference of research accomplishment in the field and what problems remain to be tackled in the future.
Insulin resistance and obesity are intimately related to a chronic low grade systemic inflammation. Interleukin-6 (IL-6) may influence the pathogenesis of obesity-related diseases. The aim of this study is to investigate the effect of body's fat mass on the relationships between -174G/C IL-6 promoter gene polymorphism, IL-6 circulating level and insulin resistance. A population of 150 Caucasian women was studied, subdivided according to their body composition in non-obese (NW), Normal Weight Obese (NWO) and preobese-obese (OB). The NWO subjects were found in an intermediate position between the NW and OB subjects in terms of body weight, fat mass percentage (FM%), abdominal FAT%, hs-CRP and plasma triglyceride level. Fasting plasma IL-6 concentration was positively correlated with the homeostasis model assessment for insulin resistance (HOMA-IR) in all subjects analyzed (P=0.0014). In NWO and OB women a significantly increased IL-6 mean value was observed compared with NW subjects. In G/G population, the IL-6 plasma level of NWO and OB was significantly higher with respect to NW. No significant differences of IL-6 concentrations were observed in the three groups carrying G/C genotype. NWO and OB women homozygous for the allele C have significantly lower value of IL-6 with respect to NW subjects. IL-6 concentration was positively correlated with FM% in G/G (R(2)=0.397, P<0.001) and was negatively correlated in C/C (R(2)=0.459, P=0.002). No significant correlation was observed in G/C genotype (R(2)=0.041, P=0.173). In conclusion our study confirms that, at least in Italian Caucasian females, the FM% is a major determinant of an increase in IL-6 production and insulin resistance. -174 G/C IL-6 promoter polymorphism represents a marker which could help to identify, time in advance, "vulnerable" individuals at risk of age and obesity related diseases.
Structure-based focusing constitutes a powerful approach to design libraries of compounds with a given biological profile. Computers with special software can be used to analyse the large amount of data usually available for the compounds. Pharmacophores can be used to identify new compounds that present a specific arrangement of features responsible for a certain type of activity. When available, information about the 3D structure of a biological target can also be included in the building of pharmacophore models. These pharmacophores can then be used as queries to search and/or focus large compound libraries. Multiple pharmacophores were generated from the 3D structure 17beta-hydroxystreoid dehydrogenase type1 complexed with different inhibitors. The validity of these pharmacophores was assessed against a test database containing known active and inactive 17beta-hydroxystreoid dehydrogenase type1 inhibitors. The most selective models were then used to search commercial databases for new structural lead molecules. This approach has allowed us to identify a few new compounds possessing structural features common to flavonoids, a structural class of compounds known to contain good inhibitors of 17beta-hydroxystreoid dehydrogenase type1 enzyme. A structure-based focusing approach is demonstrated to be a meaningful and powerful technique for identifying new lead candidates, which can be taken into the lead optimization process.
A large body of evidence on brain development and ageing has revealed that inflammatory processes profoundly affect brain functions during life span of mammalians, including humans. Activation of innate immune mechanisms leading to pro-inflammatory cytokine up-regulation is involved in devastating and disabling human brain illnesses, as Alzheimer's disease (AD), a progressive neurodegenerative disease that causes dementia in the elderly. Emerging data indicates that the cytokine Interleukin (IL)-18, one of the key mediator of inflammation and immune response, has relevance in the physiopathological processes of the brain, by ultimately influencing the integrity of neurons and putatively contributing to AD. In this review, the relationship between specific IL-18-mediated processes and AD neurodegeneration is summarized and clinical studies pointing to a role of the cytokine in the pathology are discussed. Altogether, the presented data indicate that a more complete knowledge of the molecular mechanisms underlying IL-18 implication in neuroinflammatory and neurodegenerative pathways could contribute toward the development of new therapeutic strategies for AD.
Due to its channel-like properties, the peripheral-type benzodiazepine receptor (PBR) has been renamed the translocator protein (TSPO). In eukaryotes, the TSPO is primarily located in the outer mitochondrial membrane. In prokaryotes, it is found in the cell membrane. A broad spectrum of functions has been attributed to the TSPO, including various host defense responses, developmental processes, and mitochondrial functions. In the present review, we focus on the role of TSPO in immunological responses, apoptosis, and steroidogenesis, to determine whether these functions may be governed by a common denominator including TSPO. At physiological concentrations (nM range), the TSPO specific ligands, PK 11195 and Ro5-4864, appear to be anti-apoptotic. Knockdown of TSPO by genetic manipulation, resulting a reduction by more than 50% in [(3)H]PK 11195 binding, was reported to show anti-apoptotic effects, suggesting a potential pro-apoptotic function of TSPO. However, a reduction of more than 70% of TSPO abundance was found to cause cell death, possibly due to impairment of other essential cell functions. The pro-apoptotic function of TSPO may involve the modulation of the channel formed by the mitochondrial voltage-dependent anion channel (VDAC) and the adenine nucleotide transporter (ANT) [i.e., the mitochondrial permeability transition pore (MPTP)]. The frequently reported pro-apoptotic effects of PK 11195 and Ro5-4864 may be due to sites with low-affinity binding for these specific TSPO ligands, and not directly related to VDAC and ANT. Also at concentrations in the nM range, PK 11195 and Ro5-4864 appear to stimulate steroidogenesis. For this function TSPO by itself appears to suffice i.e. no involvement of VDAC and ANT. TSPO appears to operate as a translocator/channel to transfer cholesterol into mitochondria where it is converted to pregnenolone, a precursor of further steroidogenesis. Apoptosis and steroids play important roles in various aspects of the host defense response. Thus, our review suggests that the involvement of TSPO and its ligands in such seemingly disparate biological functions as immunological responses, apoptosis, and steroidogenesis may have a common denominator in the multi-dimensional role of TSPO in the host-defense response to disease and injury.
A disintegrin and metalloproteinase 19 (ADAM19, or adamalysin 19) is a cell surface glycoprotein with a signal sequence, a prodomain, a metalloproteinase domain, a disintegrin domain, a cysteine-rich domain, a epidermal growth factor-like domain, a transmembrane domain, and a cytoplasmic domain. It is an endopeptidase that cleaves extracellular matrix proteins and sheds growth factors and cytokines such as neuregulins, heparin-binding epidermal growth factor, tumor necrosis factor (TNF)-alpha, and TNF-related activation-induced cytokine. The ADAM19 gene was cloned from human, monkey, and mouse. It is expressed in multiple organs and tissues including heart, lung, bones, brain, spleen, liver, skeletal muscle, kidney, and testes. ADAM19 plays essential roles in embryo implantation, cardiovascular morphogenesis, neurogenesis, and other developmental processes. It has constitutive alpha-secretase activity associated with processing Alzheimer's disease amyloid precursor protein (APP) to non-amyloidogenic fragments; thus, it is neuroprotective. Those observations indicate that inhibition of ADAM19 activity is undesirable during embryo development and morphogenesis, and during the development of Alzheimer's disease. On the contrary, in adults, ADAM19 is upregulated in human brain tumors such as astrocytoma and glioblastoma and is correlated with the invasiveness of glioma. It is also over-expressed by many human cancerous cell lines including cancers of the colon, ovary, lung, and brain. Abnormally high expression of ADAM19 is also linked to inflammation and fibrosis of the lung and kidney. Targeted inhibition of ADAM19 may be crucial for the treatment of certain types of tumors and inflammatory diseases.
Interleukin-19 (IL-19) is a member of the IL-10 family of cytokines. The last ten years from the finding of IL-19, investigations underline the role of IL-19 in the immunological diseases. It is known that expression of IL-19 is increased in the epidermis of patients with psoriasis, which is a Th1 dominant disease. Increased concentration of IL-19 has also been found in the serum of patients with asthma, which is a Th2 dominant disease. There is an increasing body of data demonstrating that IL-19 is associated with the pathogenesis of both Th1 and Th2 dominant diseases. Regarding the role of IL-19 on the innate immunity and inflammation, interestingly, in vitro studies have shown that lipopolysaccharide can stimulate human monocytes and macrophages to upregulate the expression of IL-19. IL- 19 is upregulated in macrophages after infection and lessens inflammation by suppressing the production of tumor necrosis factor-α , IL-6 and IL-12, but not by inducing IL-10. In addition, IL-19-deficient mice are susceptible to experimental colitis induced by dextran sodium sulfate, a disease which is characterized by excessive inflammatory responses of local macrophages and epithelial cells to intestinal microflora. In this review, we discuss our current understanding of the role of IL-19 in autoimmune and inflammatory diseases.
Growing interests have been focused on the development of hybrid-analogs with modifications of the A-ring and the side chain of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3]. An exocyclic methylene group at C-10, a hydroxy group at C-1 and a hydroxy group at C-3 play a crucial role in the expression of biological activities of 1alpha,25(OH)2D3. However, relationship between the functional groups and activities has not been fully understood. We have synthesized and evaluated biological activities of several singly dehydroxylated A-ring analogs of 19-nor-1alpha,25(OH)2D3 and 19-nor-22-oxa-1alpha,25(OH)2D3. All of them have an extremely low binding affinity for vitamin D receptor (VDR). Some of them lack the 1alpha-hydroxy group that is considered to be essential for VDR-mediated gene expression, have greater or equivalent potencies to 1alpha,25(OH)2D3 for inducing differentiation and cell cycle G0-G1 arrest of human promyelocytic leukemia cells as well as for the transactivation of target genes including a rat 25-hydroxyvitamin D3-24-hydroxylase gene promoter and a human osteocalcin gene promoter in transfected mammalian cells. The assessment of a ligand/VDR/Retinoid X receptor complex formation using a two-hybrid luciferase assay revealed that the liganded VDR has high potency to form a heterodimer, but this could not explain the high biological potency of the 19-nor analogs. Other reason(s) including an interaction with transcriptional cofactors should be considered to explain the mechanism of action of 19-nor analogs.
Tubulin protein is a major target of drug molecules, and consequently, tubulin inhibitors have attracted great attention as antimitotic antitumor agents for chemotherapeutic use. Hundreds of synthetic or semisynthetic tubulin inhibitors have been discovered and developed recently that are related to the natural products colchicine, vinblastine, and taxol. Representatives include allothiocolchicinoids, vinorelbine, and taxotere. This review will describe the recent progress being made in the development of novel antimitotic antitumor tubulin inhibitors. The emphasis has been placed on related research in the author's laboratory, including development of colchicine derivatives and other colchicine binding site drugs, such as flavonoids and quinolone derivatives. Syntheses and modifications of novel compounds, biological activity evaluation, and structural activity relationships will be discussed as well. Further research will undoubtedly lead to the discovery of additional tubulin inhibitors that have potential for use as anticancer drugs.
The 1950s saw the clinical introduction of the first two specifically antidepressant drugs: iproniazid, a monoamine-oxidase inhibitor that had been used in the treatment of tuberculosis, and imipramine, the first drug in the tricyclic antidepressant family. Iproniazid and imipramine made two fundamental contributions to the development of psychiatry: one of a social-health nature, consisting in an authentic change in the psychiatric care of depressive patients; and the other of a purely pharmacological nature, since these agents have constituted an indispensable research tool for neurobiology and psychopharmacology, permitting, among other things, the postulation of the first aetiopathogenic hypotheses of depressive disorders. The clinical introduction of fluoxetine, a selective serotonin reuptake inhibitor, in the late 1980s, once again revolutionized therapy for depression, opening the way for new families of antidepressants. The present work reviews, from a historical perspective, the entire process that led to the discovery of these drugs, as well as their contribution to the development of the neuroscientific disciplines. However, all of these antidepressants, like the rest of those currently available for clinical practice, share the same action mechanism, which involves the modulation of monoaminergic neurotransmission at a synaptic level, so that the future of antidepressant therapy would seem to revolve around the search for extraneuronal non-aminergic mechanisms or mechanisms that modulate the intraneuronal biochemical pathways.
CB 1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide] has been the subject of continued interest for over 30 years. As an anti-cancer agent, it represents one of the very few examples of a compound that shows real anti-tumor selectivity. Unfortunately, for the treatment of human disease, this anti-tumor selectivity was seen only in certain rat tumors. The basis for the anti-tumor selectivity of CB 1954 is that it is a prodrug that is enzymatically activated to generate a difunctional agent, which can form DNA-DNA interstrand crosslinks. The bioactivation of CB 1954 in rat cells involves the aerobic reduction of its 4-nitro group to a 4-hydroxylamine by the enzyme NQO1 (DT-diaphorase). The human form of NQO1 metabolizes CB 1954 much less efficiently than rat NQO1. Thus human tumors are insensitive to CB 1954. In view of the proven success of CB 1954 in the rat system, it would be highly desirable to re-create its anti-tumor activity in man. This has led to the development of CB 1954 analogs and other prodrugs activated by nitroreduction such, as those based on a self-immolative activation mechanism. A gene therapy-based approach for targeting cancer cells and making them sensitive to CB 1954 and related compounds has been developed. VDEPT (gene-directed enzyme prodrug therapy) has been used to express an E. coli nitroreductase in tumor cells and human tumor cells transduced to express this enzyme are very sensitive to prodrugs activated by nitroreduction. CB 1954 is in clinical trial for this application. Recently it has been shown that a latent nitroreductase is present in some human tumors. This is NQO2--an enzyme that requires for activity, the non-biogenic compound dihydronicotinamide riboside (NRH) as a cosubstrate. When active, NQO2 is 3000 times more effective than human DT-diaphorase in the reduction of CB 1954. NRH and reduced pyridinium derivatives that, like NRH, act as co-substrates for NQO2, produce a dramatic increase in the cytotoxicity of CB 1954 against human cell lines in vitro and its anti-tumor activity against certain human xenografts in vivo. NQO2 activity is substantially raised in tumor samples from colorectal and hepatoma patients (up to 14-fold). A phase I clinical trial of an NQO2 co-substrate with CB 1954 is scheduled.
IL-12 has demonstrated remarkable antitumor activity when used directly as a recombinant protein or when different viral or non-viral vectors transfer its genes. At enhancing tumor immunity, IL-12 acts as a bridge between innate and adaptive immune responses due to its ability to induce proliferation and activation of NK, NKT, and T cells. In addition, IL-12 inhibits tumor angiogenesis mainly through IFN gamma-dependent production of the chemokine IP10. As a result, IL-12 can eliminate several types of tumors developed in rodents. Pre-clinical experience forecasted a quick and successful clinical translation, but the encouraging results observed in animals were not reproduced in patients. Moreover, unacceptable toxicity resulting from IFN gamma overproduction was observed in 2 renal carcinoma patients included in a phase II clinical trial that consisted in systemic administration of rIL-12. As a consequence, development of IL-12 as an antitumor agent was temporarily halted while the high expectations raised among clinicians faded away. Gene transfer methods are designed to confine IL-12 production in the tumor environment preventing systemic toxicity. Tumor cells, dendritic cells, or autologous fibroblasts have been transfected with recombinant adenoviruses or retroviruses to secrete IL-12 locally, showing good efficacy and safety profiles. IL-12 combination with other immunotherapy approaches synergizes to achieve even better results. Encouraging pilot clinical results have been recently obtained from the first phase I trial studying adenovirus mediated in vivo gene transfer of IL-12 into lesions of advanced cancer patients. Further improvements will follow from: i) increases in the efficacy of gene transduction; ii) development of tumor specific promoters; iii) development of regulatable and long-term expression vectors and iv) combination with other immunological and non-immunological anticancer therapies.
Schizophrenia is a complex psychiatric disorder characterised by positive and negative symptoms, cognitive impairments, attentional problems, anxiety and depressive symptoms. The use of atypical antipsychotics has generally improved clinical outcome yet medical need remains in the treatment of this disease. The potential use of 5-HT(1A) receptor agonism is emerging as one potential area that could be exploited to improve clinical management of the disease. 5-HT(1A) receptor agonism will not reduce hyperprolactinaemia but does appear to enhance effects on positive, negative and cognitive symptoms and also treat attentional depressive and anxiety symptoms. However, these improvements are not at the expense extrapyramidal side effects and indeed may attenuate the effects of D(2) receptor antagonism. Agonism at the 5-HT(1A) receptor might therefore offer potential benefits to the pallet of existing strategies for the treatment of schizophrenia. We review existing data in support of this. However, further clinical data are needed to prove these hypotheses.
Clara cell 10-kDa protein (CC10)/ uteroglobin (UG) is a nonglycoprotein with a molecular mass of 16 kilodaltons, which is produced by mucosal epithelial cells in the lung (Clara cells), uterus and prostate. Like other low molecular weigh proteins it is catabolized in renal proximal tubules. Structurally it is a homodimer of subunits of 70 amino acids covalently bound in an antiparallel manner. It belongs to secretogobin (SCGB) family and is assigned as subgroup 1A1. The function of the protein so far elucidated is immunoregulatory and anti-inflammatory in innate immunity. The knockout mouse of UG gene resulted in aggravation of inflammation by allergic and hyperoxic stimuli. It also showed very similar pathological features with human IgA nephropathy. The value is changed in the lung fluid and serum of various inflammatory and allergic lung diseases. Several kinds of single nucleotide polymorphisms (SNPs) in human CC10/UG gene were recently discovered; Adenine allele accumulation in G38A SNP has possible association with asthma and IgA nephropathy, being paralleled with disease severity of IgA nephropathy. Its expression is enhanced by some transcriptional factors induced by cytokines such as interferon-gamma. For cancer cells, the protein functions as an antagonist of neoplastic phenotype. CC10/UG forms one of intra- and intercellular regulators involved in inflammation and malignant transformation in the respiratory and urogenital fields.
Diabetes is a prevalent disease which effects over 150 million people worldwide and there is a great medical need for new therapeutic agents to treat it. Inhibition of protein tyrosine phosphatase 1B (PTP1B) has emerged as a highly validated, attractive target for treatment of not only diabetes but also obesity. Discovery of small-molecule inhibitors has been pursued extensively in both academia and industry and a number of very potent and selective inhibitors have been identified. With X-ray crystallography, the binding interactions of several classes of inhibitors have been elucidated. This has resulted in significant progress in understanding important interactions between inhibitors and specific residues of PTP1B, which could help the design of future inhibitors. However, since the active site of PTP1B that most of these inhibitors bind to is highly hydrophilic, it remains a challenge to identify inhibitors with both excellent in vitro potency and drug-like physiochemical properties which would lead to good in vivo activities.
A large number of IL-1 protein sequences have become available recently from a range of vertebrate species and especially from bony fish. However, 3D structures are still only known for mammalian IL-1. In this review, we use a multiple sequence alignment of all published non-mammalian vertebrate IL-1beta proteins to locate the structurally important residues critical for maintaining the beta-trefoil fold and we investigate the degree to which functionally important residues involved in receptor binding are conserved across vertebrate species. We find that although there is a high level of variability of positions involved in receptor binding, the mode of binding and overall shape of the ligand-receptor complex is probably maintained. This implies that each species has evolved its own unique interleukin-1 signalling system through ligand-receptor co-evolution. Nonetheless, the IL-1beta processing mechanism in non-mammalian vertebrates remains unclear because, with the exception of three bony fish, all non-mammalian IL-1beta sequences discovered so far lack an ICE (Interleukin Converting Enzyme) cut site. The IL-1 system has become an important drug target because of its significance in inflammatory diseases. Research on peptides derived from IL-1beta has identified peptides that possess agonist activity in humans and in trout, and peptides with antagonist activity. The agonist peptides map to two distinct loop regions of IL-1beta that are known to interact with the flexible domain III of the corresponding receptor. Further analysis of the IL-1 system may prove useful in engineering IL-1 with improved features and in suggesting new avenues for therapeutic intervention.
Over the past decade, Lymphocyte Function-Associated Antigen-1 (LFA-1, alphaLbeta2, CD11a/CD18) has emerged as an attractive therapeutic target for the treatment of multiple inflammatory diseases. Its established role in the trafficking and activation of leukocytes coupled with the recent elucidation of the global conformational changes that govern its function continue to drive pharmaceutical interest in this target. This sustained interest has led to the implementation of numerous drug discovery strategies leading to the development of antibodies, peptidomimetics, and small molecules that block LFA-1 function. The most successful demonstration of clinical efficacy to date has been with Raptiva, a humanized anti-LFA-1 antibody. In clinical trials of patients with moderate to severe psoriasis, improvements in several disease specific parameters including the Psoriasis Area and Severity Index (PASI) were observed. This review article will provide an overview of LFA-1 biology and structural regulation, as well as strategies that have been adopted in pursuit of effective therapies. Recent findings with different classes of small molecule antagonists will be highlighted with an emphasis on how their different mechanisms of action on the inserted domain (I domain) of CD11a have impacted our understanding of LFA-1 function and illuminated other potential avenues for therapeutic intervention.
A series of 2-(hydrazinocarbonyl)-3-substituted-phenyl-1H-indole-5-sulfonamides possessing various 2-, 3- or 4- substituted phenyl groups with methyl-, halogeno- and methoxy- functionalities, as well as the perfluorophenyl moiety have been synthesized and evaluated as inhibitors of both α- and β-class carbonic anhydrases (CAs, EC 184.108.40.206). All human isoforms with medicinal chemistry applications were included in such studies, among which CA I, II, VA, VB, VII, IX and XII. Several low nanomolar, sometimes isoform-selective compounds were thus detected. Two β-CAs from the pathogenic bacterium Mycobacterium tuberculosis encoded by the genes Rv1284 Rv3588c were also highly inhibited (sometimes in the sub-nanomolar range) by some pyridinium derivatives incoprorating this scaffold, obtained from the corresponding 2-(hydrazinocarbonyl)-3-substituted-phenyl-1H-indole-5-sulfonamides by reaction with pyrylium salts. The fungal β-CAs from Candida albicans (Nce103) and Cryptococcus neoformans (Can2) were also investigated for their inhibition with this family of sulfonamides and some highly effective inhibitors detected. As the X-ray crystal structure of one such sulfonamide with the human isoform CA II is also know, the 3-substituted-phenyl-1H-indole-5-sulfonamides represent a totally new class of inhibitors obtained by structure-based drug design, which show efficiency in inhibiting both α- and β-CAs from several species.
Insulin-like growth factor 1 receptor (IGF-1R) is important in cancer pathogenesis and progression. While its signaling pathway is an interesting therapeutic target, recent clinical trials have exhibited limited effects; however, significant crosstalks between IGF-1R and other signaling pathways have garnered increasing attention. These complex networks include interactions between IGF-1R and receptor tyrosine kinases (RTKs), including insulin receptor (IR), epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), mesenchymal-epithelial transition factor (MET), platelet-derived growth factor receptor (PDGFR), and fibroblast growth factor receptor (FGFR). Furthermore, IGF-1R also is related to steroid hormones, including estrogen receptors alpha and beta (ERα and ERβ), androgen receptor (AR), and progesterone receptor (PR). Cumulatively, actions of crosstalk between IGF-1R, and RTKs/steroid hormones promote tumorigenesis, as demonstrated by the effectiveness of recently proposed therapeutic strategies. These therapeutic strategies, primarily pertaining to crosstalk-cotargeting, exhibited notable advantages in overcoming resistance to conventional chemotherapy and conventional endocrine therapy. Furthermore, these techniques offer benefits beyond the limited effects of single-agent targeting previously reported. Thus, the role of crosstalk between IGF-1R and RTKs/steroid hormones, including strategies to block these pathways in combination with recent development in this field, were reviewed and the potential future cancer therapeutics suggested by this rationale were considered.
The insulin-like growth factors (IGF) and their receptors play pivotal roles in cellular signaling transduction and thus regulate cell growth, differentiation, apoptosis, transformation and other important physiological progresses. The insulin-like growth factor 1 receptor (IGF-1R) mainly engages in the Ras/mitogen-activated protein kinase (MAPK) pathway and the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway, and also forms cross-talk with the epidermal growth factor receptor (EGFR) pathway. Currently, it draws more attention since its overexpression has been demonstrated in various human cancers, such as colorectal cancer, breast cancer, prostate cancer and lung tumors, thus the strategy targeting the IGF-1R would be promising in treatment of these cancers. There are already dozens of agents developed for the inhibition of IGF-1R, which are categorized into monoclonal antibodies, small molecule inhibitors and so on. While in this review, small molecule inhibitors would be the focus for detailed discussion. Herein, we updated previously reported research papers and reviews in this field and summarized developments of small molecule inhibitors up to 2011. Finally, we proposed the application of network pharmacology methods to reconsider the clinical use of inhibitors with concomitant IR inhibition or other kinases inhibition, hoping that more optimal combinations would be obtained for cancer therapy.