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As a continuation of previous efforts in mapping functional hot spots on the bile acid scaffold, we here demonstrate that the introduction of a hydroxy group at the C11β position affords high selectivity for FXR. In particular, the synthesis and FXR/TGR5 activity of novel bile acids bearing different hydroxylation patterns at the C ring are reported and discussed from a structure-activity standpoint. The results obtained led us to discover the first bile acid derivative endowed with high potency and selectivity at the FXR receptor, 3α,7α,11β-trihydroxy-6α-ethyl-5β-cholan-24-oic acid (TC-100, 7) which also shows a remarkable physicochemical and pharmacological profile. Compound 7 combines the excellent physicochemical properties of hydrophilic bile acids such as ursodeoxycholic acid, with the distinct ability to specifically bind and regulate FXR activity in vivo, thus providing a bona fide novel therapeutic agent to treat enterohepatic disorders such as cholestasis, NASH, and inflammatory bowel disease. [ABSTRACT FROM AUTHOR]

The nuclear receptor ss DAF-12 has been recognized as the key molecular player regulating the life cycle of the nematode parasite Strongyloides stercoralis . ss DAF-12 ligands permit the receptor to function as an on/off switch modulating infection, making it vulnerable to therapeutic intervention. In this study, we report the design and synthesis of a set of novel dafachronic acid derivatives, which were used to outline the first structure-activity relationship targeting the ss DAF-12 receptor and to unveil hidden properties shared by the molecular shape of steroidal ligands that are relevant to the receptor binding and modulation. Moreover, biological results led to the discovery of sulfonamide 3 as a submicromolar ss DAF-12 agonist endowed with a high receptor selectivity, no toxicity, and improved properties, as well as to the identification of unprecedented ss DAF-12 antagonists that can be exploited in the search for novel chemical tools and alternative therapeutic approaches for treating parasitism such as Strongyloidiasis.

Tankyrases (TNKSs) have recently gained great consideration as potential targets in Wnt/β-catenin pathway-dependent solid tumors. Previously, we reported the 2-mercaptoquinazolin-4-one MC2050 as a micromolar PARP1 inhibitor. Here we show how the resolution of the X-ray structure of PARP1 in complex with MC2050, combined with the computational investigation of the structural differences between TNKSs and PARP1/2 active sites, provided the rationale for a structure-based drug design campaign that with a limited synthetic effort led to the discovery of the bis-quinazolinone 5 as a picomolar and selective TNKS2 inhibitor, endowed with antiproliferative effects in a colorectal cancer cell line (DLD-1) where the Wnt pathway is constitutively activated., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

The discovery of lead compounds relies on the iterative generation of structure-activity relationship data resulting from the synthesis and biological evaluation of hit analogues. Using traditional approaches, a significant time delay may occur from compound design to results, leading to slow and expensive hit-to-lead explorations. Herein, we have exploited the use of chemical toolboxes to expedite lead discovery and optimization. In particular, the integration of flow synthesizers, automation, process analytical technologies, and computational chemistry has provided a prototype system enabling the multicomponent flow synthesis, in-line analysis, and characterization of chiral tetracyclic quinolines as a novel class of PXR agonists. Within 29 compounds, a novel template 19b (3a S ,11 R ,11a S ) was identified with an EC 50 of 1.2 μM (efficacy 119%) at the PXR receptor., Competing Interests: The authors declare no competing financial interest.