ABSTRACT
We report the design, synthesis, and biological evaluation of some potent small-molecule neuropilin-1 (NRP1) antagonists. NRP1 is implicated in the immune response to tumors, particularly in Treg cell fragility, required for PD1 checkpoint blockade. The design of these compounds was based on a previously identified compound EG00229. The design of these molecules was informed and supported by X-ray crystal structures. Compound 1 (EG01377) was identified as having properties suitable for further investigation. Compound 1 was then tested in several in vitro assays and was shown to have antiangiogenic, antimigratory, and antitumor effects. Remarkably, 1 was shown to be selective for NRP1 over the closely related protein NRP2. In purified Nrp1+, FoxP3+, and CD25+ populations of Tregs from mice, 1 was able to block a glioma-conditioned medium-induced increase in TGFß production. This comprehensive characterization of a small-molecule NRP1 antagonist provides the basis for future in vivo studies.
Subject(s)
Immunomodulation/drug effects , Neuropilin-1/antagonists & inhibitors , Small Molecule Libraries/pharmacology , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/metabolism , Transforming Growth Factor beta/biosynthesis , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/pharmacology , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Drug Design , Humans , Mice , Models, Molecular , Molecular Conformation , Pentanoic Acids/chemistry , Pentanoic Acids/pharmacology , Small Molecule Libraries/chemistry , T-Lymphocytes, Regulatory/immunology , Vascular Endothelial Growth Factor A/pharmacologyABSTRACT
Succinate dehydrogenase (SDH) and fumarate hydratase (FH) are components of the tricarboxylic acid (TCA) cycle and tumor suppressors. Loss of SDH or FH induces pseudohypoxia, a major tumor-supporting event, which is the activation of hypoxia-inducible factor (HIF) under normoxia. In SDH- or FH-deficient cells, HIF activation is due to HIF1alpha stabilization by succinate or fumarate, respectively, either of which, when in excess, inhibits HIFalpha prolyl hydroxylase (PHD). To reactivate PHD, we focused on its substrate, alpha-ketoglutarate. We designed and synthesized cell-permeating alpha-ketoglutarate derivatives, which build up rapidly and preferentially in cells with a dysfunctional TCA cycle. This study shows that succinate- or fumarate-mediated inhibition of PHD is competitive and is reversed by pharmacologically elevating intracellular alpha-ketoglutarate. Introduction of alpha-ketoglutarate derivatives restores normal PHD activity and HIF1alpha levels to SDH-suppressed cells, indicating new therapy possibilities for the cancers associated with TCA cycle dysfunction.
Subject(s)
Cell Hypoxia/drug effects , Cell Membrane Permeability , Ketoglutaric Acids/chemistry , Ketoglutaric Acids/pharmacology , Succinate Dehydrogenase/deficiency , Succinate Dehydrogenase/metabolism , Cell Line , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Ketoglutaric Acids/metabolism , Molecular Structure , Proteasome Endopeptidase Complex/metabolism , Protein Binding , Succinate Dehydrogenase/genetics , Ubiquitin/metabolismABSTRACT
[reaction: see text] Reaction of homoallylic alcohols with aldehydes in the presence of TFA gives, after hydrolysis of the ester, 4-hydroxy-2,3,6-trisubstituted tetrahydropyrans with the creation of three new stereocenters in a single-pot process. By varying the aldehyde component, a variety of functionalized side chains are installed at C-2. The utility of this approach is extended to the enantioselective synthesis of tetrahydropyrans with >99% ee.
ABSTRACT
The first syntheses of two natural products, catechols 1 and 2, isolated from Plectranthus sylvestris (labiatae), are reported. Oxygen-18 labeling studies support the proposed intermediacy of a stabilized benzylic cation in the acid-promoted cyclization of an aldehyde and benzylic homoallylic alcohol possessing an electron-rich aromatic ring. In contrast, with an electron-deficient aromatic ring the pathway via a benzylic cation is only minor. [reaction: see text]
Subject(s)
Biological Factors/chemical synthesis , Catechols/chemical synthesis , Cyclization , Anti-Inflammatory Agents/chemical synthesis , Antioxidants/chemical synthesis , Lamiaceae/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , StereoisomerismABSTRACT
[reaction: see text] Evidence is presented here for the mechanism of the Prins cyclization of benzylic homoallylic alcohols, which shows that the outcome of the reaction is dependent upon the substituents on the aromatic ring. The presence of an electron-rich aromatic ring favors an oxonia-Cope rearrangement yielding a symmetrical tetrahydropyran as the major product formed via a side-chain exchange process. In contrast, with electron-deficient aromatic rings the expected 2,4,6-trisubstituted tetrahydropyran is formed.
