J. Scott Sawyer

Development of TGF-|[beta]| signalling inhibitors for cancer therapy

The transforming growth factor-β (TGF-β) superfamily of ligands has a pivotal role in the regulation of a wide variety of physiological processes from development to pathogenesis. Since the discovery of the prototypic member, TGF-β, almost 20 years ago, there have been tremendous advances in our understanding of the complex biology of this superfamily. Deregulation of TGF-β has been implicated in the pathogenesis of a variety of diseases, including cancer and fibrosis. Here we present the rationale for evaluating TGF-β signalling inhibitors as cancer therapeutics, the structures of small-molecule inhibitors that are in development and the targeted drug discovery model that is being applied to their development.

Selective desilylation of tert-butyldimethylsilyl ethers of phenols using potassium fluoride-alumina and ultrasound

The use of potassium fluoride on basic alumina in acetonitrile with ultrasound for the selecting deprotection of tert-butyldimethylsilyl ethers of phenols is described. The method, which features a non-aqueous work-up, readily cleaves tert-butyldimethylsilyl ethers of phenols at room temperature, whereas tert-butyldimethylsilyl ethers of benzyl alcohols or 2-(trimethylsilyl)ethoxymethyl ethers of phenols are stable.

A novel and selective method for the N-arylation of indoles mediated by KFAl2O3☆

Abstract Indole was reacted with aryl electrophiles in the presence of 37% KF Al 2 O 3 and catalytic 18-crown-6 in DMSO at 120 °C to give selectively 1-arylindoles in fair to excellent yield. Electrophiles containing electronically unfavorable substitution patterns or leaving groups, such as 3-chlorobenzonitrile, coupled effectively under the reaction conditions.

Blockade of human neutrophil activation by 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]propoxy]phenoxy]benzoic acid (LY293111), a novel leukotriene B4 receptor antagonist

Leukotriene B4 (LTB4), a naturally occurring pro-inflammatory product of arachidonic acid metabolism, has been associated with human inflammatory disease. This study compares the abilities of two LTB4 receptor antagonists, 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]- propoxy]phenoxy]benzoic acid (LY293111) and 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]- 3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid (SC-41930), to displace LTB4 binding and their functional blockade of human neutrophil activation. LY293111 inhibited the binding of [3H]LTB4 with a Ki of 25 nM; SC-41930 displayed a similar potency (Ki = 17 nM). In contrast, LY293111 prevented LTB4-induced calcium mobilization with an IC50 = 20 nM, or 40 times more effectively than SC-41930 (IC50 = 808 nM). LY293111 was 300 times more potent than SC-41930 in blocking LTB4-induced CD11b up-regulation on isolated neutrophils. LY293111 also arrested LTB4-induced up-regulation of CD11b on neutrophils in whole human blood. LY293111 was not effective in blocking human neutrophil activation responses induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP), platelet-activating factor (PAF), human recombinant endothelial interleukin-8 (IL-8) or human recombinant complement component 5a (C5a).

Optimization of a Dihydropyrrolopyrazole Series of Transforming Growth Factor-β Type I Receptor Kinase Domain Inhibitors: Discovery of an Orally Bioavailable Transforming Growth Factor-β Receptor Type I Inhibitor as Antitumor Agent

In our continuing effort to expand the SAR of the quinoline domain of dihydropyrrolopyrazole series, we have discovered compound 15d, which demonstrated the antitumor efficacy with oral bioavailability. This effort also demonstrated that the PK/PD in vivo target inhibition paradigm is an effective approach to assess potential for antitumor efficacy. The dihydropyrrolopyrazole inhibitor 15d (LY2109761) is representative of a novel series of antitumor agents.

QUINOLINE-SUBSTITUTED DIHYDROINDOLES AS CYSLT1 (LTD4 RECEPTOR) ANTAGONISTS

Abstract A series of quinoline-substituted dihydroindoles has been synthesized and evaluated as antagonists of the cysLT 1 receptor. This series, exemplified by 2 (LY302905; pKi = 8.3 for inhibition of binding of 3 H-LTD 4 to guinea pig lung membranes), represents reduced analogues of the corresponding indoles that were previously shown to be potent, orally active cysLT 1 receptor antagonists. These dihydroindole compounds generally displayed increased in vitro and in vivo (oral) activity.

Structural analogues of LY292728, a highly potent xanthone dicarboxylic acid leukotriene B4 receptor antagonist: spatial positioning of the secondary acid group

Abstract We report the preparation and pharmacologic activity of three spatial analogues of LY292728, a highly potent xanthone dicarboxylic LTB4 receptor antagonist. Molecular modeling of these compounds has helped to further elucidate the nature of the secondary acid binding site of the LTB4 receptor.

Preclinical assessment of galunisertib (LY2157299 monohydrate), a first-in-class transforming growth factor-β receptor type I inhibitor

Transforming growth factor-β (TGFβ) is an important driver of tumor growth via intrinsic and extrinsic mechanisms, and is therefore an attractive target for developing cancer therapeutics. Using preclinical models, we characterized the anti-tumor activity of a small molecule inhibitor of TGFβ receptor I (TGFβRI), galunisertib (LY2157299 monohydrate). Galunisertib demonstrated potent and selective inhibition of TGFβRI with corresponding inhibition of downstream signaling via inhibition of SMAD phosphorylation (pSMAD). Galunisertib also inhibited TGFβ-induced pSMAD in vivo, which enabled a pharmacokinetic/pharmacodynamic profile in Calu6 and EMT6-LM2 tumors. Galunisertib demonstrated anti-tumor activity including inhibition of tumor cell migration and mesenchymal phenotype, reversal of TGFβ-mediated immune-suppression, and tumor growth delay. A concentration-effect relationship was established with a dosing schedule to achieve the optimal level of target modulation. Finally, a rat model demonstrated a correlation between galunisertib-dependent inhibition of pSMAD in tumor tissues and in PBMCs, supporting the use of PBMCs for assessing pharmacodynamic effects. Galunisertib has been tested in several clinical studies with evidence of anti-tumor activity observed in subsets of patients. Here, we demonstrate that galunisertib inhibits a number of TGFβ-dependent functions leading to anti-tumor activity. The enhanced understanding of galunisertib provides rationale for further informed clinical development of TGFβ pathway inhibitors.