Naoyuki Kanzaki

T140 analogs as CXCR4 antagonists identified as anti‐metastatic agents in the treatment of breast cancer

A chemokine receptor, CXCR4, and its endogenous ligand, stromal cell‐derived factor‐1 (SDF‐1), have been recognized to be involved in the metastasis of several types of cancers. T140 analogs are peptidic CXCR4 antagonists composed of 14 amino acid residues that were previously developed as anti‐HIV agents having inhibitory activity against HIV‐entry through its co‐receptor, CXCR4. Herein, we report that these compounds effectively inhibited SDF‐1‐induced migration of human breast cancer cells (MDA‐MB‐231), human leukemia T cells (Sup‐T1) and human umbilical vein endothelial cells at concentrations of 10–100 nM in vitro. Furthermore, slow release administration by subcutaneous injection using an Alzet osmotic pump of a potent and bio‐stable T140 analog, 4F‐benzoyl‐TN14003, gave a partial, but statistically significant (P≤0.05 (t‐test)) reduction in pulmonary metastasis of MDA‐MB‐231 in SCID mice, even though no attempt was made to inhibit other important targets such as CCR7. These results suggest that T140 analogs have potential use for cancer therapy, and that small molecular CXCR4 antagonists could potentially replace neutralizing antibodies as anti‐metastatic agents for breast cancer.

TAK-652 inhibits CCR5-mediated human immunodeficiency virus type 1 infection in vitro and has favorable pharmacokinetics in humans.

ABSTRACT The first small-molecule CCR5 antagonist, TAK-779, could not be developed as an anti-human immunodeficiency virus type (anti-HIV-1) agent because of its poor oral bioavailability. TAK-652 is an orally bioavailable TAK-779 derivative with potent anti-HIV-1 activity. TAK-652 inhibited the binding of RANTES (regulated on activation, normal T-cell expressed and secreted), macrophage inflammatory protein 1α (MIP-1α), and MIP-1β to CCR5-expressing cells at nanomolar concentrations. TAK-652 could also suppress the binding of monocyte chemotactic protein 1 (MCP-1) to CCR2b-expressing cells. However, its inhibitory effect on ligand binding to other chemokine receptors was limited. TAK-652 was active against CCR5-using (R5) HIV-1 but totally inactive against CXCR4-using (X4) HIV-1. The compound was active against R5 HIV-1 clinical isolates containing reverse transcriptase and protease inhibitor-resistant mutations, with a mean 50% effective concentration (EC50) and EC90 of 0.061 and 0.25 nM, respectively. In addition, recombinant R5 viruses carrying different subtype (A to G) envelope proteins were equally susceptible to TAK-652. A single oral administration of TAK-652 up to 100 mg was safe and well tolerated in humans. The compound displayed favorable pharmacokinetics, and its plasma concentration was 7.2 ng/ml (9.1 nM) even 24 h after the administration of 25 mg. Thus, TAK-652 is a promising candidate as a novel entry inhibitor of HIV-1.

Optimization of (2,3-dihydro-1-benzofuran-3-yl)acetic acids: discovery of a non-free fatty acid-like, highly bioavailable G protein-coupled receptor 40/free fatty acid receptor 1 agonist as a glucose-dependent insulinotropic agent.

G protein-coupled receptor 40 (GPR40)/free fatty acid receptor 1 (FFA1) is a free fatty acid (FFA) receptor that mediates FFA-amplified glucose-stimulated insulin secretion in pancreatic β-cells. We previously identified (2,3-dihydro-1-benzofuran-3-yl)acetic acid derivative 2 as a candidate, but it had relatively high lipophilicity. Adding a polar functional group on 2 yielded several compounds with lower lipophilicity and little effect on caspase-3/7 activity at 30 μM (a marker of toxicity in human HepG2 hepatocytes). Three optimized compounds showed promising pharmacokinetic profiles with good in vivo effects. Of these, compound 16 had the lowest lipophilicity. Metabolic analysis of 16 showed a long-acting PK profile due to high resistance to β-oxidation. Oral administration of 16 significantly reduced plasma glucose excursion and increased insulin secretion during an OGTT in type 2 diabetic rats. Compound 16 (TAK-875) is being evaluated in human clinical trials for the treatment of type 2 diabetes.

Analysis of Binding Sites for the New Small-Molecule CCR5 Antagonist TAK-220 on Human CCR5

ABSTRACT G protein-coupled receptor CCR5 is the main coreceptor for macrophage-tropic human immunodeficiency virus type 1 (HIV-1), and various small-molecule CCR5 antagonists are being developed to treat HIV-1 infection. It has been reported that such CCR5 antagonists, including TAK-779, bind to a putative binding pocket formed by transmembrane domains (TMs) 1, 2, 3 and 7 of CCR5, indicating the importance of the conformational changes of the TMs during virus entry. In this report, using a single-round infection assay with human CCR5 and its substitution mutants, we demonstrated that a new CCR5 antagonist, TAK-220, shares the putative interacting amino acid residues Asn252 and Leu255 in TM6 with TAK-779 but also requires the distinct residues Gly163 and Ile198 in TMs 4 and 5, respectively, for its inhibitory effect. We suggested that, together with molecular models of the interactions between the drugs and CCR5, the inhibitory activity of TAK-220 could involve direct interactions with amino acid residues in TMs 4, 5, and 6 in addition to those in the previously postulated binding pocket. The possible interaction of drugs with additional regions of the CCR5 molecule would help to develop a new small-molecule CCR5 antagonist.

Highly Potent Inhibition of Human Immunodeficiency Virus Type 1 Replication by TAK-220, an Orally Bioavailable Small-Molecule CCR5 Antagonist

ABSTRACT TAK-220 is a member of a novel class of chemokine receptor antagonists and is highly specific to CCR5, as determined by receptor binding and calcium mobilization assays. The compound selectively inhibited coreceptor-mediated entry of human immunodeficiency virus type 1 (HIV-1) into host cells and HIV-1 infection mediated by CCR5. TAK-220 inhibited the replication of six CCR5-using (R5) HIV-1 clinical isolates in peripheral blood mononuclear cells (PBMCs) with a mean 90% effective concentration of 13 nM. The anti-HIV-1 activity of TAK-220 was not affected by addition of high concentrations of human serum. It equally inhibited R5 HIV-1 replication in PBMCs obtained from eight different donors, irrespective of the levels of viral production. Furthermore, the anti-HIV-1 activity of TAK-220 was found to be subtype independent. TAK-220 did not induce CCR5 internalization but blocked the binding of two monoclonal antibodies that recognize the second extracellular loop of CCR5 in CCR5-expressing cells. These results suggest that TAK-220 selectively inhibits R5 HIV-1 replication by interfering with coreceptor-mediated entry of the virus into host cells. At a dose of 5 mg/kg of body weight, TAK-220 showed oral bioavailabilities of 9.5 and 28.9% in rats and monkeys, respectively. Thus, TAK-220 is a promising candidate for the treatment of HIV-1 infection.

Inhibitory Effects of Small-Molecule CCR5 Antagonists on Human Immunodeficiency Virus Type 1 Envelope-Mediated Membrane Fusion and Viral Replication

ABSTRACT We established a human immunodeficiency virus type 1 (HIV-1) envelope (Env)-mediated membrane fusion assay and examined the small-molecule CCR5 antagonist TAK-779 and its derivatives for their inhibitory effects on HIV-1 Env-mediated membrane fusion and viral replication. The membrane fusion assay is based on HIV-1 long terminal repeat-directed β-d-galactosidase reporter gene expression in CD4- and CCR5-expressed HeLa (MAGI-CCR5) cells after cocultivation with effector 293T cells expressing HIV-1 Env. Inhibition of HIV-1 replication was also determined in MAGI-CCR5 cells infected with the corresponding cell-free HIV-1. TAK-779 effectively suppressed R5 HIV-1 (strain JR-FL) Env-mediated membrane fusion as well as viral replication. Its 50% inhibitory concentrations (IC50s) for membrane fusion and viral replication were 0.87 ± 0.11 and 1.4 ± 0.1 nM, respectively. These values corresponded well to the IC50 for 125I-RANTES (regulated on activation, T cell expressed, and secreted) binding to CCR5 (1.4 nM). The inhibitory effects of 18 TAK-779 derivatives on membrane fusion differed from one compound to another. However, there was a close correlation among their inhibitory effects on membrane fusion, viral replication, and RANTES binding. The correlation coefficient between their IC50s for membrane fusion and viral replication was 0.881. Furthermore, since this assay depends on Env expressed in the effector cells, it is also applicable to the evaluation of CXCR4 antagonists. These results indicate that the HIV-1 Env-mediated membrane fusion assay is a useful tool for the evaluation of entry inhibitors.

Thieno[2,3-d]pyrimidine-2-carboxamides bearing a carboxybenzene group at 5-position: Highly potent, selective, and orally available MMP-13 inhibitors interacting with the S1 binding site

On the basis of X-ray co-crystal structures of matrix metalloproteinase-13 (MMP-13) in complex with its inhibitors, our structure-based drug design (SBDD) strategy was directed to achieving high affinity through optimal protein-ligand interaction with the unique S1″ hydrophobic specificity pocket. This report details the optimization of lead compound 44 to highly potent and selective MMP-13 inhibitors based on fused pyrimidine scaffolds represented by the thienopyrimidin-4-one 26c. Furthermore, we have examined the release of collagen fragments from bovine nasal cartilage in response to a combination of IL-1 and oncostatin M.

Discovery of the First Potent and Orally Available Agonist of the Orphan G-Protein-Coupled Receptor 52

G-protein-coupled receptor 52 (GPR52) is an orphan Gs-coupled G-protein-coupled receptor. GPR52 inhibits dopamine D2 receptor signaling and activates dopamine D1/N-methyl-d-aspartate receptors via intracellular cAMP accumulation, and therefore, GPR52 agonists may have potential as a novel class of antipsychotics. A series of GPR52 agonists with a bicyclic core was designed to fix the conformation of the phenethyl ether moiety of compounds 2a and 2b. 3-[2-(3-Chloro-5-fluorobenzyl)-1-benzothiophen-7-yl]-N-(2-methoxyethyl)benzamide 7m showed potent activity (pEC50 = 7.53 ± 0.08) and good pharmacokinetic properties. Compound 7m significantly suppressed methamphetamine-induced hyperactivity in mice after oral administration of 3 mg/kg without disturbance of motor function.

Design, synthesis, and biological evaluation of 4-phenylpyrrole derivatives as novel androgen receptor antagonists

A series of 4-phenylpyrrole derivatives D were designed, synthesized, and evaluated for their potential as novel orally available androgen receptor antagonists therapeutically effective against castration-resistant prostate cancers. 4-Phenylpyrrole compound 1 exhibited androgen receptor (AR) antagonistic activity against T877A and W741C mutant-type ARs as well as wild-type AR. An arylmethyl group incorporated into compound 1 contributed to enhancement of antagonistic activity. Compound 4n, 1-{[6-chloro-5-(hydroxymethyl)pyridin-3-yl]methyl}-4-(4-cyanophenyl)-2,5-dimethyl-1H-pyrrole-3-carbonitrile exhibited inhibitory effects on tumor cell growth against the bicalutamide-resistant LNCaP-cxD2 cell line as well as the androgen receptor-dependent JDCaP cell line in a mouse xenograft model. These results demonstrate that this series of pyrrole compounds are novel androgen receptor antagonists with efficacy against prostate cancer cells, including castration-resistant prostate cancers such as bicalutamide-resistant prostate cancer.

Discovery of pyrrolo[2,3-d]pyrimidin-4-ones as corticotropin-releasing factor 1 receptor antagonists with a carbonyl-based hydrogen bonding acceptor

A new class of pyrrolo[2,3-d]pyrimidin-4-one corticotropin-releasing factor 1 (CRF(1)) receptor antagonists has been designed and synthesized. In general, reported CRF(1) receptor antagonists possess a sp(2)-nitrogen atom as hydrogen bonding acceptor (HBA) on their core scaffolds. We proposed to use a carbonyl group of pyrrolo[2,3-d]pyrimidin-4-one derivatives as a replacement for the sp(2)-nitrogen atom as HBA in classical CRF(1) receptor antagonists. As a result, several pyrrolo[2,3-d]pyrimidin-4-one derivatives showed CRF(1) receptor binding affinity with IC(50) values in the submicromolar range. Ex vivo (125)I-sauvagine binding studies showed that 2-(dipropylamino)-3,7-dimethyl-5-(2,4,6-trimethylphenyl)-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one (16b) (30 mg/kg, p.o.) was able to penetrate into the brain and inhibit radioligand binding to CRF(1) receptors (frontal cortex, olfactory bulb, and pituitary) in mice. We identified pyrrolo[2,3-d]pyrimidin-4-one derivatives as the first CRF(1) antagonists with a carbonyl-based HBA.