Discovery of tetrahydroquinolines and benzomorpholines as novel potent RORγt agonists

Discovery of Biaryl Amide Derivatives as Potent, Selective, and Orally Bioavailable RORγt Agonists for Cancer Immunotherapy

The master transcription factor receptor retinoic acid receptor-related orphan receptor γt (RORγt) regulates the differentiation of T-helper 17 (Th17) cells and the production of interleukin-17 (IL-17). Activation of RORγt+ T cells in the tumor microenvironment promotes immune infiltration to more effectively inhibit tumor growth. Therefore, RORγt agonists provide a reachable approach to cancer immunotherapy. Herein, a series of biaryl amide derivatives as novel RORγt agonists were designed, synthesized, and evaluated. Starting from the reported RORγt inverse agonist GSK805 (1), "functionality switching" and structure-based drug optimization led to the discovery of a promising RORγt agonist lead compound 14, which displayed potent and selective RORγt agonist activity and significantly improved metabolic stability. With excellent in vivo pharmacokinetic profiles, compound 14 demonstrated robust efficacy in preclinical tumor models of mouse B16F10 melanoma and LLC lung adenocarcinoma. Taken together, current studies indicate that 14 deserves further investigation as a potential lead RORγt agonist for cancer immunotherapy.

Discovery of novel triazine derivatives as potent retinoic acid receptor-related orphan receptor γt (RORγt) inverse agonists

Retinoic Acid Receptor-Related Orphan Receptor γt (RORγt) has been exploited as a promising target for the new small molecule therapeutics to treat inflammatory and autoimmune diseases via modulating the interleukin-17 (IL-17) production by T helper 17 (Th17) cells. Herein, we reported a series of triazine-based derivatives as novel RORγt inverse agonists. By screening of our in-house compound library, the hit compound 1 was identified with weak RORγt inhibitory activity. Subsequently, we engineered detailed structural modifications to explore the structure-activity relationships (SARs) of triazines derivatives, which led to discovery of a number of potent RORγt inverse agonists with IC₅₀ values in the range of 7 nM-50 nM in RORγt dual FRET assay. Among them, compound 14g displayed potent RORγt inverse agonistic activity with an IC₅₀ value of 22.9 nM in dual FRET assay. In a cell-based reporter gene assay, compound 14g showed an IC₅₀ value of 0.428 μM and maximum inhibition rate of 108.9%. Compound 14g also exhibited good metabolic stability and a decent pharmacokinetic profile with a low clearance (CL = 0.229 L/h/kg) and a reasonable oral exposure (AUC_0-Last = 5058 ng/mL*h). Most importantly, 14g alleviated the severity of imiquimod-induced psoriasis in mice. Taken together, triazine-based derivatives represent a new chemical class of RORγt inverse agonists as potential therapeutic agents against autoimmune diseases.

Modes of action insights from the crystallographic structures of retinoic acid receptor-related orphan receptor-γt (RORγt)

RORγt plays an important role in mediating IL-17 production and some tumor cells. It has four functional domains, of which the ligand-binding domain (LBD) is responsible for binding agonists to recruit co-activators or inverse agonists to prevent co-activator recruiting the agonists. Thus, potent ligands targeting the LBD of this protein could provide novel treatments for cancer and autoimmune diseases. In this perspective, we summarized and discussed various modes of action (MOA) of RORγt-ligand binding structures. The ligands can bind with RORγt at either orthosteric site or the allosteric site, and the binding modes at these two sites are different for agonists and inverse agonist. At the orthosteric site, the binding of agonist is to stabilize the H479-Y502-F506 triplet interaction network of RORγt. The binding of inverse agonist features as these four apparent ways: (1) blocking the entrance of the agonist pocket in RORγt; (2) directly breaking the H479-Y502 pair interactions; (3) destabilizing the triplet H479-Y502-F506 interaction network through perturbing the conformation of the side chain in M358 at the bottom of the binding pocket; (4) and destabilizing the triplet H479-Y502-F506 through changing the conformation of the side chain of residue W317 side chain. At the allosteric site of RORγt, the binding of inverse agonist was found recently to inhibit the activation of protein by interacting directly with H12, which results in unfolding of helix 11' and orientation of H12 to directly block cofactor peptide binding. This overview of recent advances in the RORγt structures is expected to provide a guidance of designing more potent drugs to treat RORγt-related diseases.

RORγt agonist enhances anti-PD-1 therapy by promoting monocyte-derived dendritic cells through CXCL10 in cancers

Background

The overall response rate to checkpoint blockade remains unsatisfactory, partially due to the immune-suppressive tumor microenvironment. A retinoic acid-related orphan receptor γt (RORγt) agonist (LYC-55716) is currently used in clinical trials combined with anti-PD-1, but how the Th17 cell transcription factor RORγt enhances antitumor immunity of PD-1 in the tumor microenvironment remains elusive.

Methods

The expression of mRNA was analyzed using qPCR assays. Flow cytometry was used to sort and profile cells. Cell migration was analyzed using Transwell assays. Biacore was used to determine the binding affinity to the RORγt protein. The RORγt GAL4 cell-based reporter gene assay was used to measure activity in the RORγt driven luciferase reporter gene expression.

Results

We designed a potent and selective small-molecule RORγt agonist (8-074) that shows robust antitumor efficacy in syngeneic tumor models and improves the efficacy of anti‑PD‑1 in a murine lung cancer model. RORγt agonist treatment increased intratumoral CD8+ T cells, which were correlated with CXCL10 and monocyte-derived dendritic cells (MoDCs). In addition, the RORγt agonist promoted Type 17 T cell migration by upregulating CCL20 and CCR6 expression, and Type 17 T cell tumor infiltration. CCL20 induces MoDCs migration, and CXCL10 derived from MoDCs promotes CD8+ T cell migration.

Conclusion

Our results revealed that the RORγt agonist improved the efficacy of anti-PD-1. The RORγt agonist increased the migration of MoDCs, which increased the local levels of CXCL10, thus promoting CD8+ T cell tumor infiltration. Our findings provide the mechanistic insights implicating the RORγt agonist in immunotherapy and offer a strategy for targeting the RORγt agonist to improve PD-1 antibody efficacy in cancers.

RORγt agonist synergizes with CTLA-4 antibody to inhibit tumor growth through inhibition of Treg cells via TGF-β signaling in cancer

To date, the overall response rate to checkpoint blockade remains unsatisfactory, partially due to the limited understanding of the tumor immune microenvironment. The retinoic acid-related orphan receptor γt (RORγt) is the key transcription factor of T helper cell 17 (Th17) cells and plays an essential role in tumor immunity. In this study, we used JG-1, a potent and selective small-molecule RORγt agonist to evaluate the therapeutic potential and mechanism of action of targeting RORγt in tumor immunity. JG-1 promotes Th17 cells differentiation and inhibition of regulatory T (Treg) cells differentiation. JG-1 demonstrates robust tumor growth inhibition in multiple syngeneic models and shows a synergic effect with the Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) antibody. In tumors, JG-1 not only promotes Th17 cells differentiation and increases C-C Motif Chemokine Receptor 6 (CCR6)- Chemokine (C-C motif) ligand 20 (CCL20) expression, but also inhibits both the expression of transforming growth factor-β1 (TGF-β1) and the differentiation and infiltration of Treg cells. In summary, JG-1 is a lead compound showing a potent activity in vitro and robust tumor growth inhibition in vivo with synergetic effects with anti-CTLA-4.

Metal-free regioselective C5-cyanoalkylation of the 8-aminoquinolineamides/sulfonamides via oxidative cross-dehydrogenative coupling with alkylnitriles

A practical, versatile and Metal-free regioselective C5-cyanoalkylation of the 8-aminoquinolineamides/sulfonamides with acetonitrile has been described.