Author: BioactiveCompoundLibrary

With the growing tools of small molecules, the modulation of these networks of interactions represents a promising therapeutic strategy. Protein-protein interaction inhibitors are certainly the next generation of highly innovative drugs that will reach the market in the next decade. As a consequence of this enthusiasm, the exponential increase of published biomedical literature on PPIs and their inhibition has prompted the development of internet services and databases that help scientists to manage the available information. There is now a growing number of structural databases dedicated to proteinprotein interactions. A large variety of these PPIs databases depict protein-protein interactions at a structural level, but they focus only on this particular interface without taking into account the potential inhibitors related to one of the two partners. In a recent survey, Higuerueolo et al. analyzed the atomic interactions and profile of small molecules disrupting PPIs in the TIMBAL database, focusing on small molecules properties and comparing these results to drug-like databases. Several other studies have also focused on subsets of small molecules that disrupt PPIs. However, none of them have focused on both the protein-protein structural information available and the known inhibitors within the interface. We describe here a chemical space, 2P2IDB, which is a handcurated database dedicated to the structure of Protein-Protein complexes with known inhibitors thereby offering complementary information to these previous analyses. We have analyzed the protein/protein and protein/inhibitor interfaces in terms of geometrical parameters, atom and residue properties, buried accessible surface area and other biophysical parameters, such as the protein-protein dissociation constant of a complex. The interfaces found in 2P2IDB were then compared to those of representative datasets of heterodimeric complexes from Bahadur and Zacharias or from the ProtorP parameters of a globular protein, or a short peptide. Complexes in 2P2IDB present globally the same shape than standard heterodimeric complexes, but their accessible surface areas are significantly smaller. More strikingly, no major conformational changes are observed between the different states of the proteins. The interfaces are also more hydrophobic than general PPIs�� interfaces, with less charged residues and more non-polar atoms. Moreover, fifty percent of the complexes in the 2P2IDB dataset possess more hydrogen bonds than typical protein-protein complexes. A set of key descriptors were identified to distinguish between PPIs with known inhibitors and representative transient complexes in the protein databank. Transient protein-protein complexes are defined as protomers that, in vivo, can exist either on their own or in complex and also undergo an exchange between the free and complexed form. A new classification based on these parameters is proposed with potential aims for the future to identify potential new druggable PPI targets. As our goal was to define structural parameters that guide the development of PPI disruptors, we only considered those protein families for which a high resolution three dimensional structure was available for both the protein/protein and the protein/ inhibitor complexes. SCH772984 942183-80-4 Homodimers and covalently bound inhibitors were not taken into account due to their different behavior. When available, the best resolution structure of the LY2835219 in vivo unbound form of the proteins or a close homologue was included. The dataset was built through data mining from the literature and by exhaustive search of the Protein Data Bank.

STAT5A1*6 has two amino acid substitutions and it is constitutively phosphorylated, localized in the cell nucleus and transcriptionally active in the absence of IL-3. In the BaFiso system presented here, the protective potential of myr-Akt is slightly greater than that provided by STAT5A1*6, which may be explained by the greater expression of myr-Akt. The design of the screen relies on the lack of relevant crosstalk between the pathways engineered to support IL-3 independent survival. Previous work has shown that the induced expression of bcl-xL and pim-1 promotes the IL-3-independent survival of Ba/F3 cells upon activation of STAT5. In contrast, studies in multiple cell lines suggest that Akt phosphorylates and inactivates proapoptotic proteins such as GSK-3b, Foxo3a and Bad in response to IL-3. We confirmed that the activation of Stat5 signaling in BCS cells did not increase Akt activity either in the presence or absence of IL-3. Another common source of interference to be SP600125 JNK inhibitor mitigated in multiplexed screening procedures is the bleed-through of fluorescence from one BIBW2992 EGFR/HER2 inhibitor channel to the other. BaFiso allows simultaneous viewing of three different fluorescent signals and sharp separation of the emission signals from the cyan and yellow protein is achieved using a special filter set. We implemented BaFiso as an automated live-cell assay using a multidrop dispenser, a robotic workstation and a robotic cell imaging platform. We assessed the properties of this HTS co-culture assay using a panel of test compounds of known activity. The cytotoxicity of the test compounds was monitored by quantifying the DRAQ5 labelled cells and all compounds tested except LiCl and Minerval reduced the viability of Ba/F3 cells. The fact that only two compounds known to selectively interfere with Akt signaling, Akt inhibitor X and UCN-01, reduced the number of yellow tagged BYA cells demonstrates the specificity of the BaFiso system. The Akt inhibitor X is a N-substituted phenoxazine that inhibits the activity of Akt even in the absence of its pleckstrin homology domain and it has been suggested that it may bind in the ATP binding site. In contrast, UCN-01 has been reported to inhibit several kinases including PDK1, a key regulator of Akt activity. Interestingly, staurosporine that differs from UCN-01 only by the absence of a hydroxy group on the lactam ring failed to change the ratio of the BaFiso cell lines. A specificity analysis against a kinase panel revealed different patterns of inhibition for UCN-01 with respect to staurosporine. It remains to be determined if these differences in specificity could account for the different behaviour observed for these two compounds in the BaFiso assay. The BaFiso screening design presented here offers some major advantages over traditional in vitro biochemical assays or more classical cellular assays. Co-culture and simultaneous testing of the paired isogenic cell lines in this assay provides an internal control and eliminates errors resulting from separate assessments. BaFiso is an image based high throughput assay that enables compound that produce artefacts and cytotoxicity to be identified on a single cell basis. Live cell imaging of the BaFiso cell lines permits the repeated monitoring of the same cells over the timecourse of an experiment, leading to a more accurate assessment that minimizes the variability in cell numbers between wells. Finally, the dual fluorescence co-culture system used in BaFiso is adaptable to any gene or pathway that can support IL-3 independent survival of Ba/F3 cells. Friedreich ataxia is an inherited recessive disorder characterized by progressive neurological disability and heart disease. Onset is usually in childhood, but it may vary from infancy to adulthood. Atrophy of sensory and cerebellar pathways causes ataxia, dysarthria, fixation instability, deep sensory loss and loss of tendon reflexes.

Relevant to neuronal activity, AMPKmediated changes in long-term potentiation are mTOR-dependent. Differences in acute seizure test profiles between three different treatments that affect AMPK activity support the hypothesis that downstream effects of neuronal mTOR inhibition likely depend on additional factors specific to each intervention. Rapamycin is known to bind FKBP12 to specifically inhibit mTORC1activity. Evidence that rapamycin acts similarly in vivo is shown by the ability of rapamycin and its derivatives to decrease recurrent seizures in animals and patients where TORC1 activity is abnormally high. Thus, it generally is LY294002 154447-36-6 assumed that rapamycin exerts its antiseizure actions by decreasing TORC1 activity. Protection in drug-induced chronic seizure models raises the possibility that mTOR inhibitors reverse a seizureinduced increase in the mTOR pathway. Specifically, after kainic acid-induced status epilepticus, increases in mTOR activity are noted 1-6 h after seizure onset, then decrease to baseline values, only to increase again 3 days after onset. Both of these increases are reversed by administration of rapamycin. However, the connection between mTOR activity and excessive neuronal activity during seizures is not clear. mTOR activity is required in dendrites for arbor and spine morphogenesis in some studies, raising the possibility that these changes in neuronal morphology may impact seizures and/or epilepsy. Rapamycin also inhibits mossy fiber sprouting in a Fingolimod number of models of status epilepticus. However, the importance of inhibiting mossy fiber sprouting is unclear because rapamycin can prevent mossy fiber sprouting without protecting against seizures after pilocarpine-induced status epilepticus. Electrophysiologically, mTOR is necessary for long-term potentiation and long-term depression.The effect of rapamycin on synaptic transmission may be mediated via decreased neuronal excitability and/or neurotransmitter release. Whether these morphological and physiological effects are the specific mechanism of seizure protection is unclear. In summary, decreased rapamycin-related neuronal excitability in some paradigms may be the result of mTOR inhibition but these studies do not rule out the possibility of an “off-target” effect, particularly given the broad effects of mTOR activity on protein synthesis, lipid metabolism, and autophagy. The limited seizure protection after a 3 d rapamycin exposure in the seizure-na? ��ve mice studied here may be due to unintended deleterious effects of prolonged mTOR suppression, in contrast to physiological mTOR suppressors where mTOR activity eventually rebounds. Another potential explanation is that the 3 d rapamycin regimen used here may suppress activity of the other mTOR protein complex, TORC2, with a subsequent deleterious effect on Akt activity. Consistent with only transient protection in the MES-T test, there may be an optimal degree of timing or extent of mTOR suppression that confers seizure protection in preclinical tests, though it is conceivably difficult to pharmacologically achieve such a balance. Finally, rapamycin is unlikely to have global antiseizure benefits, as it fails to protect in a model of infantile spasms induced by betamethasone and NMDA, even when administered before and after spasms started. Pretreatment or sustained exposure to rapamycin appears to be necessary to prevent seizures in preclinical models, as outlined previously. A requirement for prolonged rapamycin treatment is consistent with our finding that a 3-day treatment with rapamycin is more effective than a short 6 h treatment prior to kainic acid-induced seizures.

On the basis of their selectivity for PKCs and CAMKs, we chose to primarily focus on the 4-azaindole series of inhibitors, since they clearly displayed greater selectivity for PKD1 than the quinolinylmethylenethiazolinone derivative. 4-Azaindoles have previously been developed and characterized as inhibitors of p38a/b by Trejo et al.. Compounds 140 and 139 have been designed to reduce the oxidation at the 4-pyridyl nitrogen, a predominant site of metabolic oxidation. As a result of this modification, in vivo efficacy has been demonstrated for compounds 140 and 139 in an acute rat model of LPS-stimulated TNFa synthesis, providing favorable pharmacokinetic parameters for compound 140. Based on the desirable drug-like physical properties and promising PK/PD values, compound 140, and most likely 139, were deemed potent and selective orally available p38 inhibitors. These findings provide strong support for further development of the 140 and 139 series of analogs as drug/lead structures towards potent and selective PKD1 inhibitors, or dual PKD1/p38 inhibitors, with in vivo activity. Although a kinase profile reveals a few additional targets of 4-azaindoles, compound 140 in general displayed excellent selectivity as compared to the non-substituted 4,7-azaindoles, indicating there remains a distinct possibility to achieve greater selectivity Pazopanib through further medicinal chemistry modifications. On the other hand, although it is desirable to obtain sole selectivity for a single kinase, multitargeted protein kinase inhibitors tailored towards a small subset of kinases with distinct biological functions could be more attrY-27632 ROCK inhibitor active therapeutically; and, in fact, this strategy has proven to be an effective treatment in oncology. In this regard, PKD inhibitors with dual action on p38a might be equally attractive therapeutically, since both kinases have been implicated in inflammatory responses and cancer development. To further explore the mechanism of actions of these active PKD1 compounds, molecular modeling technologies were utilized to investigate putative binding modes. The threedimensional structure of PKD1 was built based on high-resolution crystal structures of homologues, and the catalytic domain, which consists of two lobes and an intervening linker, was well modeled. Subsequently, docking simulations were carried out, in which all ligands were docked into the putative ATP binding pocket of the kinase domain, and the resulting docking scores were relatively high. The interactions between the active lead compound 139 and the PKD1 kinase domain were further illustrated in detail. The modeling results are congruent with our experimental findings, demonstrating that these compounds are PKD1 inhibitors binding to the ATP site of kinase domain. The computational analyses provide additional insights into the possible molecular interactions and important binding residues of PKD1 and will prove useful in our future pharmacophore refinements. Influenza is one of the most common infectious diseases, affecting millions of people around the world every year. Occasionally, it causes a catastrophic pandemic such as the “Spanish flu” in 1918, which killed 30-50 million people worldwide. The most effective means of protection against influenza is vaccination; however, its effectiveness has been limited because etiological influenza A and B viruses constantly undergo antigenetic change. Moreover, the time needed to prepare a vaccine against a newly isolated influenza virus is more than half a year. This makes an emergency vaccine preparation against a pandemic influenza virus, such as the 2009 pandemic, difficult. However, as a vaccine alternative, several anti-influenza drugs have been developed.

Recently, selective inhibitors for CDK4 have gained substantial interest. For example the orally active small molecule PD0332991, which induces G1 arrest in primary myeloma cells, prevents tumor growth by specific inhibition of CDK4/6 and is now in Phase 2 clinical trials. The natural compound fascaplysin, originally isolated from the sponge Fascaplysinopsis Bergquist, is a kinase inhibitor with enticing selectivity for CDK4 relative to the close homolog CDK2, and also shows approximately eightfold selectivity over CDK6. Approximating the dissociation constant KD with IC50 and using the relation DG0 =2RTlnKD, the difference in the free energy of binding between the CDK4/fascaplysin and CDK2/fascaplysin complexes can be calculated to 4.2 kcal/mol. Considering the close structural similarity of the active sites of CDK2, CDK4 and CDK6, and the relatively small size and rigid structure of fascaplysin, the observed selectivity is remarkable. Chemically, fascaplysin is a planar, aromatic compound with no freely rotatable single bonds. It comprises five condensed rings, the central ring includes a positively charged imminium nitrogen. An indol-NH and a carbonyl can act as H-bond donor and H-bond acceptor, respectively. The H-bond donor and H-bond acceptor in fascaplysin are oriented in parallel spaced at,2.6 A ?, a feature shared with other kinase inhibitors. The fascaplysin framework has been used to synthesise a series of selective CDK4 inhibitors, though in most cases selectivity was partially lost in the redesign process. So what are the features that could explain the remarkable selectivity of fascaplysin? There is a considerable amount of structural information on CDKs available to help addressing this question. More than 100 CDK2 structures in complex with small molecules are deposited in the protein databank. However, compared to CDK2, structural information on CDK6 and CDK4 with inhibitors bound is scarce, in fact the first CDK4 structures have only been published recently. In this work, we have studied this example of charge-determined protein-ligand interactions using a variety of methods from the molecular modelling and drug design fields. The binding of inhibitors to protein receptors with high affinity and specificity is central to structure-based drug design applications. The quest for the calculation of binding affinities remains one of the main goals of modern computational biophysical methods. The most accurate methods for calculating binding free energies are based on molecular dynamics simulations which predict the physical properties of the protein-ligand complexes based on atomistic structural models. The energetic consequences of small structural Staurosporine 62996-74-1 changes in inhibitor complexes have been successfully studied using thermodynamic integration. An added benefit of TI calculations, as compared to empirical ligand Sorafenib Raf inhibitor docking algorithms is that the former include accurate estimates of binding entropy as well as enthalpy, based on rigorous statistical thermodynamics. In this work, we specifically address the contribution of the positive charge of fascaplysin to selectivity by applying thermodynamic integration calculations. In silico, fascaplysin can be modified easily by the iso-electronic substitution of the positively charged nitrogen to a charge neutral carbon atom, resulting in a compound, which for clarity and simplicity we refer to as carbofascaplysin. By calculating the energetic effect of this substitution for the protein-inhibitor complexes of both CDK2 and CDK4, we can quantify the impact of the positive charge of fascaplysin on its specificities towards CDK2 and CDK4.