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papers about Peptide

   Apr 23

Fig compares the uptake of

Fig. 7 compares the uptake of 177Lu-DOTA-(RGD)2 in various organ/tissue of C57/BL6 mice bearing melanoma tumors at 30 min (A) and 24 h (B) p.i. in the absence/presence of excess (RGD)2. Clearly, co-injection of excess (RGD)2 almost completely blocked the tumor uptake of 177Lu-DOTA-(RGD)2 (0.39 ± 0.14 %ID/g with RGD2 vs. 3.80 ± 0.55 %ID/g without RGD2 at 30 min p.i.). The uptake of the radiotracer in normal Cyt387 research was also significantly blocked by co-injection of excess (RGD)2. For example, the uptake of 177Lu-DOTA-(RGD)2 in heart, liver, lungs, and spleen was 1.29 ± 0.31, 4.76 ± 0.94, 5.58 ± 0.17 and 3.94 ± 1.21 %ID/g, respectively, without (RGD)2, while its uptake in the same organs was only 0.18 ± 0.09, 0.66 ± 0.08, 0.40 ± 0.08 and 0.67 ± 0.20 %ID/g, respectively, in the presence of excess (RGD)2. Similar trend was observed at 24 h p.i. The blockage of radiotracer uptake observed suggests that the tumor localization of the radiotracer is indeed receptor-mediated. The partial blockage of radiotracer uptake in the heart, lungs, liver and spleen is also due the saturation of integrin αvβ3 receptors present in those organs. Moreover, similar pattern observed in the blockage study carried out at 30 min and 24 h p.i. indirectly shows that the radiolabeled conjugate is stable in vitro and probably not internalized in a significant amount.


   Apr 23

These gaps in knowledge have

These gaps in knowledge have created the need to develop tools to better understand the behavior of these drugs. PET imaging, using carbon-11 radiolabeled analogues of these acids enables a noninvasive means for measuring their peripheral organ and PF562271 penetration, pharmacokinetics and biodistribution. Such studies may provide insight into the involvement of epigenetic processes and other mechanisms in their therapeutic actions and side effects. In this article, we describe the radiosynthesis and PET imaging studies of [11C]BA [35], [11C]PBA and [11C]VPA. Each acid was radiolabeled with carbon-11 by reaction of the respective Grignard reagent with 11CO2 and then purified by semi-preparative HPLC. Lipophilicity (Log D at pH = 7.4) and plasma protein binding (PPB) were determined following published protocols. PET imaging studies were performed using adult female baboons to obtain the distribution and kinetics of these drugs and their labeled metabolites in the brain and in peripheral organs.


   Apr 23

Evaluation of C FMZ F AH and F

Evaluation of [11C]FMZ, [18F]AH114726 and [18F]GEH120348 in monkey MLN 8237 showed time-dependent regional brain distributions for all radioligands that correlated with the known distribution of GABAA/benzodiazepine receptors in the monkey brain, with the highest specific binding in the cortex and the lowest in the pons. Of the two new radioligands, [18F]AH114726 exhibited brain uptake and tissue time-radioactivity curves that were most similar to those obtained with [11C]FMZ (Fig. 4). Compared to [18F]AH114726 or [11C]FMZ, [18F]GEH120348 showed higher initial brain uptake but very different pharmacokinetics, with continued accumulation of radioactivity into the cortical regions of high GABA/benzodiazepine receptor concentrations and very little clearance from the regions of low receptor densities (striatum, cerebellum) (Fig. 4). It can be reasoned that the higher initial brain uptake of [18F]GEH120348 is due to increased lipophilicity (log D7.4 values: FMZ, 1.12; AH114726, 0.69; GEH120348, 1.62) [13]. The slower clearance of [18F]GEH120348 might be attributed to the higher binding affinity when compared with [18F]AH114726 (Ki values: FMZ, 1.3 nM; AH114726, 5.5 nM; GEH120348, 0.76 nM), or due to a combination of differences in affinity and lipophilicity. The pharmacokinetics of [18F]GE120348 in the monkey brain are remarkably similar to the results reported for [123I]iomazenil [17], the 7-iodo analog of flumazenil with a similar high affinity (KD = 0.5 nM, [18] and higher lipophilicity. An additional point of note is the regional differences we observed in the cortical uptake of [18F]AH114726 and [18F]GEH120348 when compared to [11C]FMZ, although there is no obvious explanation for such differences at this time.


   Apr 23

Consistent with our hypothesis the present study indicated

Consistent with our hypothesis, the present study indicated that Cu-64-WT4340 PET imaging of mRNA expression, non-invasively, could provide a more useful therapy monitoring tool than the currently available modalities. None of the current modalities can image oncogene mRNA SB203580 ic86 directly or monitor the effectiveness of therapy. Therefore, the present findings might help to improve the accuracy of monitoring therapeutic activity, demonstrate better evidence for non-responsive therapy, and guide substitution with an alternative regimen.
Acknowledgments
This work was supported by NIH1R44CA136306. MTTI licensed IP from E. Wickstrom/M.L. Thakur. Some of these data were presented at the Annual Meeting of SNMMI in 2012, Miami, Florida, USA.
Keywords
Orexin; PET radiotracers; Imaging; Hypocretin; Carbon-11
1. Introduction
Orexin A and orexin B (hypocretins), first discovered in 1998 [1], are neuropeptides essential for a number of hypothalamic functions. Two receptor subtypes, termed orexin-1 (OX1) and orexin-2 (OX2), have since been identified [2]. The oreixns play an important role in regulation of the sleep-wake cycle, modulating feeding behavior, and energy homeostasis [3]. Distribution studies in rat brain using in situ hybridization and immunohistochemistry (IHC) have shown that OX1 receptors are most abundantly expressed in the locus coeruleus while OX2 receptors are expressed in regions controlling arousal, such as tuberomammillary nucleus, which is an important site for the regulation of sleep and wakefulness [4].


   Apr 22

With a potent and developable

With a potent and developable series of IKK2 inhibitors in hand, we turned our attention to optimizing both the whole blood potency and the overall physicochemical properties in order to improve oral exposure. In particular, it was envisioned that incorporation of a nitrogen STA9090 into the C-2 aryl ring would lower the log P and potentially improve both cellular potency and pharmacokinetic parameters. The ‘2-position’ of the aryl ring (4) was chosen for two reasons. First, it was anticipated that a nitrogen atom at the ‘2-position’, as exemplified in compound 4, would potentially serve as a hydrogen bond acceptor for the azaindole N–H, resulting in a degree of conformational constraint that may provide a preferred orientation favoring optimal positioning of the appended meta substituent (4 vs 16). Second, it was expected that positioning the nitrogen atom at the ‘2-position’ would decrease its propensity for CYP450 inhibition, frequently observed with pyridines. In this Letter, we outline the SAR of a potent series of C-2 pyridyl substituted ‘azaindoles’ leading to the identification of compound 4m. and The synthetic pathways utilized in the preparation of C-2 pyridyl substituted ‘azaindole’ analogues reported in Figure 2 and Table 1 are outlined in Scheme 1, Scheme 2, Scheme 3, Scheme 4, Scheme 5 and Scheme 6.4 The key steps in the preparation of the tricyclic core involved a Sonogashira coupling5 between an appropriately substituted pyridyl-acetylene (e.g., 8, 15, 23) and our previously described intermediate 93f to provide bi-aryl acetylenes (e.g., 10) in yields ranging from 55% to 95%. The ring closing step to generate the tricyclic core relied on a 5-endo-dig cyclization facilitated by tert-butoxide 6 in dimethylacetamide at 85–90 °C to provide the tricyclic core derivatives (e.g., 11) in yields ranging from 55% to 90%. As depicted in Scheme 1 and Scheme 3, amide analogues 4a and 4d–s were prepared via coupling of either pyridylmethyl amine 12 or 17 with a variety of carboxylic acids in yields ranging from 51% to 99%. Scheme 6 outlines an efficient, alternative route for the preparation of lead 4m. The enantiomerically pure analogues 4b and 4c were attained from the chiral HPLC separation of 20. Amide 22a was prepared as described in Scheme 1 starting with 2-N-acetylamino-6-ethynylpyridine. 7 Amine based analogues 22b–d were prepared by the reaction of intermediate 21 with the appropriate primary or secondary amine in the presence of DBU at 175 °C to provide 22b–d in yields ranging from 30–50% ( Scheme 5).


   Apr 22

Figure Profile of JNJ Figure optionsDownload full size imageDownload as

Figure 5.
Profile of JNJ 40279486.
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In vivo, JNJ 40279486 significantly reduced the number of inflammatory eosinophils found in lung lavage 24 h after the last of four antigen challenges when dosed orally 20 min before each antigen challenge (Fig. 6). For methods see Ref. 19.
Figure 6.
JNJ 40279486 inhibits eosinophils in the lung lavage in a mouse antigen PLX4032 model. JNJ 28307474 used as a comparator.19 Animals were dosed P.O. BID 20 min prior to each antigen challenge ?P < 0.05.
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In summary, starting with a high affinity tricyclic pyrimidine lead series devoid of physiochemical acceptable properties, the introduction of a 2-amino group maintained the affinity while improving human microsomal stability. Subsequently diamine tolerance was increased which delivered compounds which were stable in rat and human, but were poorly soluble and had undesirable signals in hERG assays. The substitution of PLX4032 an aryl ring with a pyridyl ring delivered JNJ 40279486 as a potent and selective H4 receptor antagonist with desirable pharmaceutical properties that demonstrated acceptable pharmacokinetic profile and efficacy in a mouse model of inflammation.


   Apr 22

Table Results of analgesic effect

Table 2.
Results of analgesic effect of selected pyrazoline derivatives against acetic Nafamostat induced writhing method and % inhibition of COX-2 at 10 μM
EntryTest compoundNo. of writhings% Inhibition% Inhibition of COX-2a
19aR = H, Rl = CH322.2 ± 1.3523.71 ± 1.454
20aR = H, Rl = CF324.5 ± 2.3415.80 ± 1.986
25bR = SO2NH218.6 ± 1.6530.08 ± 1.287
26bR = SO2NH222.2 ± 2.6523.71 ± 2.3511
ControlControl29.1 ± 1.21—0
STDDiclofenac6.8 ± 0.5176.63 ± 0.8899b
aData are indicated as percentage of inhibition at 10 μM mean of two tests.bDiclofenac was assayed at 20 μM for COX-2.Full-size table
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The % inhibition of COX-2 in human whole blood16 for the compounds 19a, 20a, 25b, 26b ranged from 4% to 11% at 10 μM concentration. The selected compounds showed insignificant COX-2 inhibition activity, these compounds might be acting by some different mechanism of action in vivo. The results are summarized in Table 2
The four selected compounds were further evaluated for their ulcerogenic potential in rats.17 Gross observation of the isolated rat stomachs showed a normal stomach texture for all of the tested compounds with no observable hyperemia indicating a superior GI safety profile (no ulceration) in the population of the test animals at an oral dose of 300 mg/kg, when administered twice at 2 h interval in fasted rats. It was found that the diclofenac sodium; the reference standard anti-inflammatory drug; was found to cause ulceration under the same experimental conditions.


   Apr 22

The binding of with G

The binding of 7 with G-quadruplexes was first determined using UV thermal denaturation analysis. The unmodified telomeric DNA fragment 10 (Fig. 1) was used. A representative plot of the folded fraction of G-quadruplex DNA versus temperature in the absence and presence of 7 is shown in Figure 2. The melting temperature of G-quadruplex 10 (1 μM) measured at 295 nm increased 5.2 °C in the presence of 7 at 2 μM, suggesting that VX-770 7 did bind and stabilize 10. The binding constant between the two was determined from UV titration experiments (Fig. 2). When adding 10 into a solution of 7, we observed significant changes in the spectra of 7. The maximum absorbance peak at 475 nm decreased dramatically and became a shoulder peak in the complex spectra. Two new major absorbance peaks at 500 and 550 nm were observed. The peak at 550 nm clearly resulted from the shoulder peak in the spectrum of 7. Based on the UV titration spectra, the binding curve (Fig. 2) and its corresponding Scatchard plot was plotted using the GraphPad prism software. A dissociation constant (0.86 ± 0.62 μM) was extrapolated, suggesting a moderately strong binding of 7 with 10. The presence of diamino side chain in 7 could enhance the thermal stability of G-quadruplex DNA because side chains play a significant role in binding to G-quadruplex DNA.23


   Apr 22

In contrast to the tetrahydropyran SAR and

In R406 to the tetrahydropyran SAR (14 and 15) where the 4-position of the cyclohexyl ring was favourable for the introduction of a polar oxygen atom, the opposite was evident for the introduction of the lipophilic CF2 group. The 5-difluoro analogue 18 was approximately 30-fold more potent than the corresponding 4-difluoro analogue 17 in which the lipophilic CF2 group occupies a hydrophilic region of the protein close to a water molecule (data given for cis-racemic mixtures). Although 18 was highly potent in the SYK biochemical assay, almost three orders of magnitude in potency were lost in the whole blood assay. The poor whole blood activity of 18 was not readily explainable by lipophilicity, plasma protein binding or pKa (measured pKa of 7.9). hERG SAR was sensitive to substitution in the phenyl ring of the aniline moiety. 4-Substitution consistently decreased hERG activity compared to 3-substitution (2-substitution was deleterious for SYK activity). The 4-methyl analogues 19 and 20 were almost 10-fold weaker than the corresponding 3-isomers 12 and 14 in the hERG binding assay, but with comparable activity in the whole blood assay. Introduction of a methoxy substituent at the 4-position decreased hERG activity further; analogue 21 had excellent whole blood activity (pIC50 6.7) coupled with minimal inhibition of hERG (pIC50 <4.3).


   Apr 21

aMeasured by displacement of H histamine binding using

aMeasured by displacement of [3H]histamine binding using membranes of HEK293 ZM447439 transiently expressing the human H4R. pKi’s are calculated from at least three independent measurements as the mean ± SEM.bDetermined using membranes of SK-N-MC cells transiently expressing the human H4R. pKi’s are calculated from at least three independent measurements as the mean ± SEM.cpKi: Measured by displacement of [3H]granisetron binding using membranes of HEK293 cells expressing the human 5-HT3AR. pKi’s are calculated from at least two independent measurements as the mean ± SEM.Full-size table
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Figure 2.
Chemical similarity (ECFP-4 Tc) between dual and selective hits of H4R and 5-HT3AR and the endogenous ligands of H4R (histamine) and 5-HT3AR (serotonin).
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The higher complexity of the dual H4R and 5-HT3AR fragments is further illustrated by the analysis of the physical-chemical distributions of fragment hits (Fig. 3). Whereas most properties are similar when comparing the selective and the dual activity fragments (see Table S1, S2 and Figure S1 for details21), the number of rings and the heavy atom count (and associated molecular weight) are higher for the dual activity hits compared to for H4R and 5-HT3AR selective fragments (Fig. 3 and Table S2).