Background: NAMPT catalyzes the rate-limiting reaction in converting nicotinamide to NAD ϩ in cancers.
The fibroblast growth factor receptors (FGFR) are tyrosine kinases that are present in many types of endothelial and tumor cells and play an important role in tumor cell growth, survival, and migration as well as in maintaining tumor angiogenesis. Overexpression of FGFRs or aberrant regulation of their activities has been implicated in many forms of human malignancies. Therefore, targeting FGFRs represents an attractive strategy for development of cancer treatment options by simultaneously inhibiting tumor cell growth, survival, and migration as well as tumor angiogenesis. Here, we describe a potent, selective, small-molecule FGFR inhibitor, (R)-(E)-2-(4-(2-(5-(1-(3,5-Dichloropyridin-4-yl)ethoxy)-1H-indazol-3yl)vinyl)-1H-pyrazol-1-yl)ethanol, designated as LY2874455. This molecule is active against all 4 FGFRs, with a similar potency in biochemical assays. It exhibits a potent activity against FGF/FGFR-mediated signaling in several cancer cell lines and shows an excellent broad spectrum of antitumor activity in several tumor xenograft models representing the major FGF/FGFR relevant tumor histologies including lung, gastric, and bladder cancers and multiple myeloma, and with a well-defined pharmacokinetic/pharmacodynamic relationship. LY2874455 also exhibits a 6-to 9-fold in vitro and in vivo selectivity on inhibition of FGF-over VEGF-mediated target signaling in mice. Furthermore, LY2874455 did not show VEGF receptor 2-mediated toxicities such as hypertension at efficacious doses. Currently, this molecule is being evaluated for its potential use in the clinic.
Bacterial infections are mostly due to bacteria in their biofilm mode-ofgrowth, making them recalcitrant to antibiotic penetration. In addition, the number of bacterial strains intrinsically resistant to available antibiotics is alarmingly growing. This study reports that micellar nanocarriers with a poly(ethylene glycol) shell fully penetrate staphylococcal biofilms due to their biological invisibility. However, when the shell is complemented with poly(β-amino ester), these mixed-shell micelles become positively charged in the low pH environment of a biofilm, allowing not only their penetration but also their accumulation in biofilms without being washed out, as do single-shell micelles lacking the pH-adaptive feature. Accordingly, bacterial killing of multidrug resistant staphylococcal biofilms exposed to proto porphyrin IX-loaded mixed-shell micelles and after light-activation is superior compared with single-shell micelles. Subcutaneous infections in mice, induced with vancomycin-resistant, bioluminescent staphylococci can be eradicated by daily injection of photoactivatable protoporphyrin IX-loaded, mixed-shell micelles in the bloodstream and light-activation at the infected site. Micelles, which are not degraded by bacterial enzymes in the biofilm, are degraded in the liver and spleen and cleared from the body through the kidneys. Thus, adaptive micellar nanocarriers loaded with lightactivatable antimicrobials constitute a much-needed alternative to current antibiotic therapies.
An enantioselective intramolecular allylic C-H oxidation to generate optically active chromans has been accomplished under the cooperative catalysis of a palladium complex of chiral phosphoramidite ligand and 2-fluorobenzoic acid. Mechanistic studies suggest that this reaction commences with a Pd-catalyzed allylic C-H activation event and then undergoes asymmetric allylic alkoxylation. The synthetic significance of the method has been embodied by concisely building up a key chiral intermediate to access (+)-diversonol.
We report a mouse cDNA that encodes a 317-amino acid short-chain dehydrogenase which recognizes as substrates 9-cis-retinol, 11-cis-retinol, 5␣-androstan-3␣,17-diol, and 5␣-androstan-3␣-ol-17-one. This cis-retinol/androgen dehydrogenase (CRAD) shares closest amino acid similarity with mouse retinol dehydrogenase isozymes types 1 and 2 (86 and 91%, respectively). Recombinant CRAD uses NAD ؉ as its preferred cofactor and exhibits cooperative kinetics for cis-retinoids, but Michaelis-Menten kinetics for 3␣-hydroxysterols. Unlike recombinant retinol dehydrogenase isozymes, recombinant CRAD was inhibited by 4-methylpyrazole, was not stimulated by ethanol, and did not require phosphatidylcholine for optimal activity. CRAD mRNA was expressed intensely in kidney and liver, in contrast to retinol dehydrogenase isozymes, which show strong mRNA expression only in liver. CRAD mRNA expression was widespread (relative abundance): kidney (100) > liver (92) > small intestine (9) ؍ heart (9) > retinal pigment epithelium and sclera (4.5) > brain (2) > retina and vitreous (1.6) > spleen (0.7) > testis (0.6) > lung (0.4). CRAD may catalyze the first step in an enzymatic pathway from 9-cis-retinol to generate the retinoid X receptor ligand 9-cis-retinoic acid and/or may regenerate dihydrotestosterone from its catabolite 5␣-androstan-3␣,17-diol. These data also illustrate the multifunctional nature of short-chain dehydrogenases and provide a potential mechanism for androgen-retinoid interactions.The retinol (vitamin A) metabolite all-trans-retinoic acid modulates the transcription of multiple genes in diverse cells during embryogenesis and post-natally by activating three retinoic acid receptors, RAR␣, 1 RAR, and RAR␥ (1-3). An isomer of all-trans-retinoic acid, 9-cis-retinoic acid also binds with these three receptors with K d values in vitro similar to those of all-trans-retinoic acid. 9-cis-Retinoic acid, but not all-transretinoic acid, activates three other members of the steroid hormone/thyroid hormone/vitamin D/retinoid receptor superfamily, the RXRs ␣, , and ␥ (4 -6). RARs and RXRs function as heterodimers. RXRs also serve as partners for other members of the superfamily, such as thyroid hormone, vitamin D, and peroxisome proliferator-activated receptors, and can modulate gene expression as homodimers (2, 3). This multiplicity of receptors, receptor partners, and ligands suggests a mechanism for the pleiotropic effects of retinoids, but much depends on the loci of all-trans-retinoic acid and 9-cis-retinoic acid biosynthesis. Even though 9-cis-retinoic acid occurs in vivo, and has been identified as an endogenous ligand of RXR, its concentrations are lower than all-trans-retinoic acid, and it has been found only in a few tissues to date, compared with the ubiquitous distribution of all-trans-retinoic acid (7,8). Rapid conversion in vivo into the receptor inactive isomer 9,13-di-cis-RA most likely limits 9-cis-retinoic acid concentrations and effects (9, 10).All-trans-retinoic acid undergoes isomerization in cultured cells...
The first enantioselective α-allylation of aldehydes with terminal alkenes has been realized by combining asymmetric counteranion catalysis and palladium-catalyzed allylic C-H activation. This method can tolerate a wide scope of α-branched aromatic aldehydes and terminal alkenes, thus affording allylation products in high yields and with good to excellent levels of enantioselectivity. Importantly, the findings suggest a new strategy for the future creation of enantioselective C-H/C-H coupling reactions.
Retinoic acid, a hormone biosynthesized from retinol, controls numerous biological systems by regulating eukaryotic gene expression from conception through death. This work reports the cloning and expression of a liver cDNA encoding a microsomal retinol dehydrogenase (RoDH), which catalyzes the primary and rate-limiting step in retinoic acid synthesis. The predicted amino acid sequence and biochemical data obtained from the recombinant enzyme verify it as a short-chain alcohol dehydrogenase. Like microsomal RoDH, the recombinant enzyme recognized as substrate retinol bound to cellular retinol-binding protein, had higher activity with NADP rather than NAD, was stimulated by ethanol or phosphatidylcholine, was not inhibited by 4-methylpyrazole, was inhibited by phenylarsine oxide and carbenoxolone and localized to microsomes. RoDH recognized the physiological form of retinol, holocellular retinol-binding protein, with a Km of 0.9 microM, a value lower than the approximately 5 microM concentration of holocellular retinol binding protein in liver. Northern and Western blot analyses revealed RoDH expression only in rat liver, despite enzymatic activity in liver, brain, kidney, lung, and testes. These data suggest that tissue-specific isozyme(s) of short chain alcohol dehydrogenases catalyze the first step in retinoic acid biogenesis and further strengthen the evidence that the "cassette" of retinol bound to cellular retinol-binding protein serves as a physiological substrate.
A retinol dehydrogenase, RoDH(1), which recognizes holo-cellular retinol-binding protein (CRBP) as substrate, has been cloned, expressed, and identified as a short-chain dehydrogenase/reductase (Chai, X., Boerman, M. H. E. M., Zhai, Y., and Napoli, J. L. (1995) J. Biol. Chem. 270, 3900-3904). This work reports the cloning and expression of a cDNA encoding a RoDH isozyme, RoDH(II). The predicted amino acid sequence verifies RoDH(II) as a short-chain dehydrogenase/reductase, 82% identical with RoDH(I). RoDH(II) recognized the physiological form of retinol as substrate, CRBP, with a Km of 2 mM. Similar to microsomal RoDH and RoDH(I), RoDH(II) had higher activity with NADP rather than NAD, was stimulated by ethanol and phosphatidyl choline, was not inhibited by the medium-chain alcohol dehydrogenase inhibitor 4-methylpyrazole, but was inhibited by phenylarsine oxide and the short-chain dehydrogenase/reductase inhibitor carbenoxolone. Northern blot analysis detected RoDH(I) and RoDH(II) mRNA only in rat liver, but RNase protection assays revealed RoDH(I) and RoHD(II) mRNA in kidney, lung, testis, and brain. These data indicate that short-chain dehydrogenases/reductase isozymes expressed tissue-distinctively catalyze the first step of retinoic acid biogenesis from the physiologically most abundant substrate, CRBP.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.