Preclinical characterization of CPL304110 as a potent and selective inhibitor of fibroblast growth factor receptors 1, 2, and 3 for gastric, bladder, and squamous cell lung cancer.

Fibroblast Growth Factor Receptors (FGFRs) are a family of receptor tyrosine kinases expressed on a plethora of cell membranes. They play crucial roles in both embryonic development and adult tissue functions. There is an increasing amount of evidence that FGFR-mediated oncogenesis is mainly related to gene amplification, activating mutations, or translocation in tumors of various histological types. Dysregulation of FGFRs has been implicated in a wide variety of neoplasms, such as bladder, gastric, and lung cancers. Given their functional significance, FGFRs emerge as promising targets for cancer therapy. Here, we introduce CPL304100, an innovative and highly potent FGFR1-3 kinase inhibitor demonstrating excellent in vitro biological activity. Comprehensive analyses encompassed kinase assays, cell line evaluations, PK/PD studies surface plasmon resonance studies, molecular docking, and in vivo testing in mouse xenografts. CPL304110 exhibited a distinctive binding profile to FGFR1/2/3 kinase domains, accompanied by a good safety profile and favorable ADMET parameters. Selective inhibition of tumor cell lines featuring active FGFR signaling was observed, distinguishing it from cell lines lacking FGFR aberrations (FGFR1, 2, and 3). CPL304110 demonstrated efficacy in both FGFR-dependent cell lines and patient-derived tumor xenograft (PDTX) in vivo models. Comparative analyses with FDA-approved FGFR inhibitors, erdafitinib and pemigatinib, revealed certain advantages of CPL304110 in both in vitro and in vivo assessments. Encouraging preclinical results led the way for the initiation of a Phase I clinical trial (01FGFR2018; NCT04149691) to further evaluate CPL304110 as a novel anticancer therapy.

Discovery and optimization of novel pyrazole-benzimidazole CPL304110, as a potent and selective inhibitor of fibroblast growth factor receptors FGFR (1-3).

The FGFR family is characterized by four receptors (FGFR 1-4), binding to 18 ligands called fibroblast growth factors (FGFs). Aberrant activation of FGFs and their FGFRs has been implicated in a broad spectrum of human tumors. We employed the scaffolds hybridization approach, scaffold-hopping concept to synthesize a series of novel pyrazole-benzimidazole derivatives 56 (a-x). Compound 56q (CPL304110) was identified as a selective and potent pan-FGFR inhibitor for FGFR1, -2, -3 with IC50s of 0.75 nM, 0.50 nM, 3.05 nM respectively, whereas IC50 of 87.90 nM for FGFR4. Due to its favorable pharmacokinetic profile, low toxicity and potent anti-tumor activity in vivo, compound 56q is currently under evaluation in phase I clinical trial for the treatment of bladder, gastric and squamous cell lung cancers (01FGFR2018; NCT04149691).

Identification of small-molecule enhancers of arginine methylation catalyzed by coactivator-associated arginine methyltransferase 1.

Arginine methylation is a common post-translational modification that is crucial in modulating gene expression at multiple critical levels. The arginine methyltransferases (PRMTs) are envisaged as promising druggable targets, but their role in physiological and pathological pathways is far from being clear due to the limited number of modulators reported to date. In this effort, enzyme activators can be invaluable tools useful as gain-of-function reagents to interrogate the biological roles in cells and in vivo of PRMTs. Yet the identification of such molecules is rarely pursued. Herein we describe a series of aryl ureido acetamido indole carboxylates (dubbed "uracandolates"), able to increase the methylation of histone (H3) or nonhistone (polyadenylate-binding protein 1, PABP1) substrates induced by coactivator-associated arginine methyltransferase 1 (CARM1), both in in vitro and cellular settings. To the best of our knowledge, this is the first report of compounds acting as CARM1 activators.

Design of pentapeptidic BACE1 inhibitors with carboxylic acid bioisosteres at P1' and P4 positions.

We previously reported potent BACE1 inhibitors KMI-420 and KMI-570 possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. Acidic moieties at the P(1)(') and P(4) positions of KMI inhibitors are thought to be unfavorable in terms of membrane permeability across the blood-brain barrier. Herein, we replaced acidic moieties at the P(4) position with hydrogen bond accepting groups and acidic moieties at the P(1)(') position with less acidic and similar molecular-size moieties (carboxylic acid or tetrazole bioisosteres). These inhibitors exhibited improved BACE1 inhibitory activities and a thorough quantitative structure-activity relationship study was performed.

Significance of interactions of BACE1-Arg235 with its ligands and design of BACE1 inhibitors with P2 pyridine scaffold.

Recently, we reported potent substrate-based pentapeptidic BACE1 inhibitors possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. Because these inhibitors contained some natural amino acids, we would need to improve their enzymatic stability in vivo and permeability across the blood-brain barrier, so that they become practically useful. Subsequently, non-peptidic and small-sized BACE1 inhibitors possessing a heterocyclic scaffold, 2,6-pyridenedicarboxylic, chelidamic or chelidonic moiety, at the P(2) position were reported. These inhibitors were designed based on the conformer of docked inhibitor in BACE1. In this study, we discuss the role and significance of interactions between Arg235 of BACE1 and its inhibitor in BACE1 inhibitory mechanism. Moreover, we designed more potent small-sized BACE1 inhibitors with a 2,6-pyridinedicarboxylic scaffold at the P(2) position, that were optimized for the interactions with Arg235 of BACE1.

BACE1 inhibitors: optimization by replacing the P1' residue with non-acidic moiety.

Recently, we reported potent BACE1 inhibitors KMI-429, -684, and -574 possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. These inhibitors showed potent inhibitory activities in enzymatic and cell assays, especially, KMI-429 was confirmed to significantly inhibit Abeta production in vivo. However, acidic moieties at the P(4) and P(1)' positions of KMI-compounds were thought to be unfavorable for membrane permeability across the blood-brain barrier. Herein, we replaced acidic moieties at the P(4) position with other hydrogen bond acceptor groups, and these inhibitors exhibited improved BACE1 inhibitory activities in cultured cells. In this study, we replaced the acidic moieties at the P(1)' position with non-acidic and low molecular sized moieties.

Novel non-peptidic and small-sized BACE1 inhibitors.

Recently, we reported substrate-based beta-secretase (BACE1) inhibitors with a hydroxymethylcarbonyl (HMC) isostere as a substrate transition-state mimic. These inhibitors showed potent BACE1 inhibitory activities (approximately 1.2 nM IC(50)). In order to improve in vivo enzymatic stability and permeability across the blood-brain barrier, these penta-peptidic inhibitors would need to be further optimized. On the other hand, non-peptidic inhibitors possessing isophthalic residue at the P(2) position were reported from other research groups. We selected isophthalic-type aromatic residues at the P(2) position and an HMC isostere at the P(1) position as lead compounds. On the basis of the design approach focused on the conformer of docked inhibitor in BACE1, we found novel non-peptidic and small-sized BACE1 inhibitors possessing a 2,6-pyridinedicarboxylic, chelidamic or chelidonic residue at the P(2) position.

Views on amyloid hypothesis and secretase inhibitors for treating Alzheimer's disease: progress and problems.

Alzheimer's disease is a form of sporadic, age-related dementia. According to the "amyloid hypothesis", the processing of beta-amyloid precursor protein (APP) leads to the formation of senile plaque aggregates which subsequently congest normal neurological functions. Currently, prophylaxis is testimonial, while treatment relies mainly on symptomatic relief. This review emphasizes the importance of disrupting the pathological processing of APP via alpha-secretase activators, beta- and gamma-secretase inhibitors, and compounds that bind APP. The style of writing should appeal to those with strong interests in medicinal chemistry with an equal balance of medicine and chemistry.

beta-Secretase inhibitors: modification at the P4 position and improvement of inhibitory activity in cultured cells.

Recently, we reported potent and small-sized beta-secretase (BACE1) inhibitors KMI-570 and KMI-684 in which we replaced carboxylic acid groups at the P(1)(') position of KMI-420 and KMI-429, respectively, with tetrazole derivatives as carboxylic acid bioisosteres. These modifications improved significantly BACE1 inhibitory activity and chemical stability. In this study, the acidic tetrazole ring of the P(4) position of KMI-420 and KMI-570, respectively, was replaced with various hydrogen bond acceptor groups. We found BACE1 inhibitor KMI-574 that exhibited potent inhibitory activity in cultured cells as well as in vitro enzymatic assay.

Glutathione-like tripeptides as inhibitors of glutathionylspermidine synthetase. Part 2: substitution of the glycine part.

Glutathionylspermidine synthetase (GspS) is an essential enzyme in the biosynthesis of trypanothione and is an attractive target for the design of selective anti-parasitic drugs. We synthesised a series of analogues of glutathione (L-gamma-Glu-L-Leu-X) where the glycine moiety has been substituted for other amino acids. These peptides were evaluated as substrates and inhibitors of GspS. Compounds with basic side chains such as diaminopropionic acid were found to be good inhibitors (K(i): 7.2 microM). Substitution of the glycine part abolished the GspS substrate properties of the tripeptide.

Glutathione-like tripeptides as inhibitors of glutathionylspermidine synthetase. Part 1: Substitution of the glycine carboxylic acid group.

Glutathionylspermidine synthetase/amidase (GspS) is an essential enzyme in the biosynthesis and turnover of trypanothione and represents an attractive target for the design of selective anti-parasitic drugs. We synthesised a series of analogues of glutathione (L-gamma-Glu-L-Leu-Gly-X) where the glycine carboxylic acid group (X) has been substituted for other acidic groups such as tetrazole, hydroxamic acid, acylsulphonamide and boronic acid. The boronic acid appears the most promising lead compound (IC(50) of 17.2 microM).