Novel Small Molecule Tyrosine Kinase 2 Pseudokinase Ligands Block Cytokine-Induced TYK2-Mediated Signaling Pathways.

A member of the Janus kinase (JAK) family, Tyrosine Kinase 2 (TYK2), is crucial in mediating various cytokine-signaling pathways such as interleukin-23 (IL23), interleukin-12 (IL12) and type I Interferons (IFN) which contribute to autoimmune disorders (e.g., psoriasis, lupus, and inflammatory bowel disease). Thus, TYK2 represents an attractive target to develop small-molecule therapeutics for the treatment of cytokine-driven inflammatory diseases. Selective inhibition of TYK2 over other JAK isoforms is critical to achieve a favorable therapeutic index in the development of TYK2 inhibitors. However, designing small molecule inhibitors to target the adenosine triphosphate (ATP) binding site of TYK2 kinase has been challenging due to the substantial structural homology of the JAK family catalytic domains. Here, we employed an approach to target the JAK homology 2 (JH2) pseudokinase regulatory domain of the TYK2 protein. We developed a series of small-molecule TYK2 pseudokinase ligands, which suppress the TYK2 catalytic activity through allosteric regulation. The TYK2 pseudokinase-binding small molecules in this study simultaneously achieve high affinity-binding for the TYK2 JH2 domain while also affording significantly reduced affinity for the TYK2 JAK homology 1 (JH1) kinase domain. These TYK2 JH2 selective molecules, although possessing little effect on suppressing the catalytic activity of the isolated TYK2 JH1 catalytic domain in the kinase assays, can still significantly block the TYK2-mediated receptor-stimulated pathways by binding to the TYK2 JH2 domain and allosterically regulating the TYK2 JH1 kinase. These compounds are potent towards human T-cell lines and primary immune cells as well as in human whole-blood specimens. Moreover, TYK2 JH2-binding ligands exhibit remarkable selectivity of TYK2 over JAK isoforms not only biochemically but also in a panel of receptor-stimulated JAK1/JAK2/JAK3-driven cellular functional assays. In addition, the TYK2 JH2-targeting ligands also demonstrate high selectivity in a multi-kinase screening panel. The data in the current study underscores that the TYK2 JH2 pseudokinase is a promising therapeutic target for achieving a high degree of biological selectivity. Meanwhile, targeting the JH2 domain represents an appealing strategy for the development of clinically well-tolerated TYK2 inhibitors that would have superior efficacy and a favorable safety profile compared to the existing Janus kinase inhibitors against autoimmune diseases.

SHR1032, a novel STING agonist, stimulates anti-tumor immunity and directly induces AML apoptosis.

Stimulator of interferon genes (STING) activation induces type I interferons and pro-inflammatory cytokines which stimulate tumor antigen cross presentation and the adaptive immune responses against tumor. The first-generation of STING agonists, cyclic di-nucleotide (CDN), mimicked the endogenous STING ligand cyclic guanosine monophosphate adenosine monophosphate, and displayed limited clinical efficacy. Here we report the discovery of SHR1032, a novel small molecule non-CDN STING agonist. Compared to the clinical CDN STING agonist ADU-S100, SHR1032 has much higher activity in human cells with different STING haplotypes and robustly induces interferon ß (IFNß) production. When dosed intratumorally, SHR1032 induced strong anti-tumor effects in the MC38 murine syngeneic tumor model. Pharmacodynamic studies showed induction of IFNß, tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) in the tumors and, to a lower extent, in the plasma. More importantly, we found SHR1032 directly causes cell death in acute myeloid leukemia (AML) cells. In conclusion, our findings demonstrate that in addition to their established ability to boost anti-tumor immune responses, STING agonists can directly eradicate AML cells, and SHR1032 may present a new and promising therapeutic agent for cancer patients.

Automatic Detection Method of Dairy Cow Feeding Behaviour Based on YOLO Improved Model and Edge Computing.

The feeding behaviour of cows is an essential sign of their health in dairy farming. For the impression of cow health status, precise and quick assessment of cow feeding behaviour is critical. This research presents a method for monitoring dairy cow feeding behaviour utilizing edge computing and deep learning algorithms based on the characteristics of dairy cow feeding behaviour. Images of cow feeding behaviour were captured and processed in real time using an edge computing device. A DenseResNet-You Only Look Once (DRN-YOLO) deep learning method was presented to address the difficulties of existing cow feeding behaviour detection algorithms' low accuracy and sensitivity to the open farm environment. The deep learning and feature extraction enhancement of the model was improved by replacing the CSPDarknet backbone network with the self-designed DRNet backbone network based on the YOLOv4 algorithm using multiple feature scales and the Spatial Pyramid Pooling (SPP) structure to enrich the scale semantic feature interactions, finally achieving the recognition of cow feeding behaviour in the farm feeding environment. The experimental results showed that DRN-YOLO improved the accuracy, recall, and mAP by 1.70%, 1.82%, and 0.97%, respectively, compared to YOLOv4. The research results can effectively solve the problems of low recognition accuracy and insufficient feature extraction in the analysis of dairy cow feeding behaviour by traditional methods in complex breeding environments, and at the same time provide an important reference for the realization of intelligent animal husbandry and precision breeding.

Discovery of 2-(Ortho-Substituted Benzyl)-Indole Derivatives as Potent and Orally Bioavailable RORγ Agonists with Antitumor Activity.

RORγ is a dual-functional drug target, which involves not only induction of inflammation but also promotion of cancer immunity. The development of agonists of RORγ promoting Th17 cell differentiation could provide a novel mechanism of action (MOA) as an immune-activating anticancer agent. Herein, we describe new 2-(ortho-substituted benzyl)-indole derivatives as RORγ agonists by scaffold hopping based on clinical RORγ antagonist VTP-43742. Interestingly, subtle structural differences of the compounds led to the opposite biological MOA. After rational optimization for structure-activity relationship and pharmacokinetic profile, we identified a potent RORγ agonist compound 17 that was able to induce the production of IL-17 and IFNγ in tumor tissues and elicit antitumor efficacy in MC38 syngeneic mouse colorectal tumor model. This is the first comprehensive work to demonstrate the in vivo antitumor efficacy of an RORγ agonist.

A Novel CD73 Inhibitor SHR170008 Suppresses Adenosine in Tumor and Enhances Anti-Tumor Activity with PD-1 Blockade in a Mouse Model of Breast Cancer.

INTRODUCTION: CD73 and adenosine support growth-promoting neovascularization, metastasis, and survival in cells, and promote anti-PD-1 mAb therapy-induced immune escape. Consequently, developing a CD73 inhibitor as monotherapy and a potential beneficial combination partner with immune-checkpoint inhibitors needs investigation. METHODS: CD73 inhibitors were evaluated in vitro with soluble and membrane-bound CD73 enzymes, as well as its PD biomarker responses in human peripheral blood mononuclear cells (PBMC) by flow cytometry and ELISA. The binding modes of the molecules were analyzed via molecular modeling. The anti-tumor activity and synergistic effect of SHR170008 in combination with anti-PD-1 mAb were evaluated in a syngeneic mouse breast cancer model. RESULTS: SHR170008 was discovered during the initial structural modifications on the link between the ribose and the α-phosphate of AMPCP, which significantly improved the stability of the compound confirmed by the metabolite identification study. Further modifications on the adenine base of AMPCP improved the potency due to forming stronger interactions with CD73 protein. It exhibited potent inhibitory activities on soluble and endogenous membrane-bound CD73 enzymes, and induced IFNγ production, reversed AMP-suppressed CD25+ and CD8+/CD25+ expression, and enhanced granzyme B production on CD8+ T cells in human PBMC. SHR170008 showed dose-dependent anti-tumor efficacy with suppression of adenosine in the tumors in EMT6 mouse breast tumor model. The increase of adenosine in tumor tissue by anti-PD-1 mAb alone was suppressed by SHR170008 in the combination groups. Simultaneous inhibition of CD73 and PD-1 neutralization synergistically enhanced antitumor immunity and biomarkers in response, and exposures of SHR170008 were correlated with the efficacy readouts. CONCLUSION: Our findings suggest that CD73 may serve as an immune checkpoint by generating adenosine, which suppresses the antitumor activity of anti-PD-1 mAb, and inhibition of CD73 may be a potential beneficial combination partner with immune-checkpoint inhibitors to improve their therapeutic outcomes in general.

Discovery of a novel RORγ antagonist with skin-restricted exposure for topical treatment of mild to moderate psoriasis.

Clinical success of IL-17/IL-23 pathway biologics for the treatment of moderate to severe psoriasis suggests that targeting RORγt, a master regulator for the proliferation and function of Th17 cells, could be an effective alternative. However, oral RORγ antagonists (VTP43742, TAK828) with high systemic exposure showed toxicity in phase I/II clinical trials and terminated development. To alleviate the potential safety concerns, identifying compounds with skin-restricted exposure amenable for topical use is of great interest. Systematic structure activity relationship study and multi-parameter optimization led to the discovery of a novel RORγ antagonist (SHR168442) with desired properties for a topical drug. It suppressed the transcription of IL-17 gene, leading to reduction of IL-17 cytokine secretion. It showed high exposure in skin, but low in plasma. Topical application of SHR168442 in Vaseline exhibited excellent efficacy in the imiquimod-induced and IL-23-induced psoriasis-like skin inflammation mouse models and correlated with the reduction of Th17 pathway cytokines, IL-6, TNFα and IL-17A. This work demonstrated restricted skin exposure of RORγ antagonist may provide a new topical treatment option as targeted therapeutics for mild to moderate psoriasis patients and may be suitable for the treatment of any other inflammatory disorders that are accessible locally.

EBI-907, a novel BRAF(V600E) inhibitor, has potent oral anti-tumor activity and a broad kinase selectivity profile.

The oncogenic mutation of BRAF(V600E) has been found in approximately 8% of all human cancers, including more than 60% of melanoma and 10% of colorectal cancers. The clinical proof of concept in treating BRAF(V600E)-driving melanoma patients with the BRAF inhibitors has been well established. We have sought to identify and develop novel BRAF(V600E) inhibitors with more favorable profiles. Our chemistry effort has led to the discovery of EBI-907 as a novel BRAF(V600E) inhibitor with potent anti-tumor activity in vitro and in vivo. In a LanthaScreen BRAF(V600E) kinase assay, EBI-907 showed an IC50 of 4.8 nM, which is >10 -fold more potent than Vemurafenib (IC50 = 58.5 nM). In addition, EBI-907 showed a broader kinase selectivity profile, with potent activity against a number of important oncogenic kinases including FGFR1-3, RET, c-Kit, and PDGFRb. Concomitant with such properties, EBI-907 exhibits potent and selective cytotoxicity against a broader range of BRAF(V600E)-dependent cell lines including certain colorectal cancer cell lines with innate resistance to Vemurafenib. In BRAF(V600E)-dependent human Colo-205 and A375 tumor xenograft mouse models, EBI-907 caused a marked tumor regression in a dose-dependent manner, with superior efficacy to Vemurafenib. Our results also showed that combination with EGFR or MEK inhibitor enhanced the potency of EBI-907 in cell lines with innate or acquired resistance to BRAF inhibition alone. Our findings present EBI-907 as a potent and promising BRAF inhibitor, which might be useful in broader indications.

Discovery of EBI-907: A highly potent and orally active B-Raf(V600E) inhibitor for the treatment of melanoma and associated cancers.

A novel series of pyrazolo[3,4-c]isoquinoline derivatives was discovered as B-Raf(V600E) inhibitors through scaffold hopping based on a literature lead PLX4720. Further SAR exploration and optimization led to the discovery of potent B-Raf(V600E) inhibitors with good oral bioavailability in rats and dogs. One of the compounds EBI-907 (13g) demonstrated excellent in vivo efficacy in B-Raf(V600E) dependent Colo-205 tumor xenograft models in mouse and is under preclinical studies for the treatment of melanoma and B-Raf(V600E) associated cancers.

New pyrazolyl and thienyl aminohydantoins as potent BACE1 inhibitors: exploring the S2' region.

The proteolytic enzyme ß-secretase (BACE1) plays a central role in the synthesis of the pathogenic ß-amyloid in Alzheimer's disease. SAR studies of the S2' region of the BACE1 ligand binding pocket with pyrazolyl and thienyl P2' side chains are reported. These analogs exhibit low nanomolar potency for BACE1, and demonstrate >50- to 100-fold selectivity for the structurally related aspartyl proteases BACE2 and cathepsin D. Small groups attached at the nitrogen of the P2' pyrazolyl moiety, together with the P3 pyrimidine nucleus projecting into the S3 region of the binding pocket, are critical components to ligand's potency and selectivity. P2' thiophene side chain analogs are highly potent BACE1 inhibitors with excellent selectivity against cathepsin D, but only modest selectivity against BACE2. The cell-based activity of these new analogs tracked well with their increased molecular binding with EC(50) values of 0.07-0.2 µM in the ELISA assay for the most potent analogs.

5-Piperazinyl-3-sulfonylindazoles as potent and selective 5-hydroxytryptamine-6 antagonists.

As part of our efforts to develop agents for CNS diseases, we have been focused on the 5-HT(6) receptor in order to identify potent and selective ligands for cognitive enhancement. Herein we report the identification of a novel series of 5-piperazinyl-3-sulfonylindazoles as potent and selective 5-HT(6) antagonists. The synthesis, SAR, and pharmacokinetic and pharmacological activities of some of the compounds including 3-(naphthalen-1-ylsulfonyl)-5-(piperazin-1-yl)-1H-indazole (WAY-255315 or SAM-315) will be described.

Potent dihydroquinolinone dopamine D2 partial agonist/serotonin reuptake inhibitors for the treatment of schizophrenia.

A dihydroquinolinone moiety was found to be a potent serotonin reuptake inhibitor pharmacophore when combined with certain amines. This fragment was coupled with selected D(2) ligands to prepare a series of dual acting compounds with attractive in vitro profiles as dopamine D(2) partial agonists and serotonin reuptake inhibitors. Structure-activity studies revealed that the linker plays a key role in contributing to D(2) affinity, function, and SRI activity.

4-(2-Aminoethoxy)-N-(phenylsulfonyl)indoles as novel 5-HT6 receptor ligands.

The preparation of a novel class of 4-(2-aminoethoxy)-N-(phenylsulfonyl)indoles which exhibit high affinity towards the 5-HT6 receptor is reported here. Among these compounds, 4-(2-methylaminoethoxy)-N-(phenylsulfonyl)indole 5g showed superior affinity (Ki = 1 nM) towards the 5-HT6 receptor as well as excellent selectivity (> 2000-fold) against the closely related subtype 5-HT7 receptor.