ABSTRACT
While the discovery of immune checkpoint inhibitors has led to robust, durable responses in a range of cancers, many patients do not respond to currently available therapeutics. Therefore, an urgent need exists to identify alternative mechanisms to augment the immune-mediated clearance of tumors. Hematopoetic progenitor kinase 1 (HPK1) is a serine-threonine kinase that acts as a negative regulator of T-cell receptor (TCR) signaling, to dampen the immune response. Herein we describe the structure-based discovery of isofuranones as inhibitors of HPK1. Optimization of the chemotype led to improvements in potency, selectivity, plasma protein binding, and metabolic stability, culminating in the identification of compound 24. Oral administration of 24, in combination with an anti-PD1 antibody, demonstrated robust enhancement of anti-PD1 efficacy in a syngeneic tumor model of colorectal cancer.
ABSTRACT
BACKGROUND: Hematopoietic progenitor kinase 1 (HPK1 or MAP4K1) has been demonstrated as a negative intracellular immune checkpoint in mediating antitumor immunity in studies with HPK1 knockout and kinase dead mice. Pharmacological inhibition of HPK1 is desirable to investigate the role of HPK1 in human immune cells with therapeutic implications. However, a significant challenge remains to identify a small molecule inhibitor of HPK1 with sufficient potency, selectivity, and other drug-like properties suitable for proof-of-concept studies. In this report, we identified a novel, potent, and selective HPK1 small molecule kinase inhibitor, compound K (CompK). A series of studies were conducted to investigate the mechanism of action of CompK, aiming to understand its potential application in cancer immunotherapy. METHODS: Human primary T cells and dendritic cells (DCs) were investigated with CompK treatment under conditions relevant to tumor microenvironment (TME). Syngeneic tumor models were used to assess the in vivo pharmacology of CompK followed by human tumor interrogation ex vivo. RESULTS: CompK treatment demonstrated markedly enhanced human T-cell immune responses under immunosuppressive conditions relevant to the TME and an increased avidity of the T-cell receptor (TCR) to recognize viral and tumor-associated antigens (TAAs) in significant synergy with anti-PD1. Animal model studies, including 1956 sarcoma and MC38 syngeneic models, revealed improved immune responses and superb antitumor efficacy in combination of CompK with anti-PD-1. An elevated immune response induced by CompK was observed with fresh tumor samples from multiple patients with colorectal carcinoma, suggesting a mechanistic translation from mouse model to human disease. CONCLUSION: CompK treatment significantly improved human T-cell functions, with enhanced TCR avidity to recognize TAAs and tumor cytolytic activity by CD8+ T cells. Additional benefits include DC maturation and priming facilitation in tumor draining lymph node. CompK represents a novel pharmacological agent to address cancer treatment resistance.
Subject(s)
Antineoplastic Agents/administration & dosage , Bone Neoplasms/drug therapy , Ginsenosides/administration & dosage , Protein Serine-Threonine Kinases/antagonists & inhibitors , Sarcoma/drug therapy , Animals , Antineoplastic Agents/pharmacology , Bone Neoplasms/immunology , Bone Neoplasms/metabolism , Cell Line , Cell Proliferation/drug effects , Cell Survival/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Ginsenosides/pharmacology , Humans , Mice , Receptors, Antigen, T-Cell/metabolism , Sarcoma/immunology , Sarcoma/metabolism , Treatment Outcome , Tumor Microenvironment/drug effects , Xenograft Model Antitumor AssaysABSTRACT
Modulating GPR88 activity is suggested to have therapeutic utility in the treatment of CNS disorders, such as schizophrenia. This Letter will describe the discovery and SAR development of a class of potent GPR88 agonists.
Subject(s)
Amides/pharmacology , Amines/pharmacology , Central Nervous System Diseases/drug therapy , Drug Discovery , Receptors, G-Protein-Coupled/agonists , Amides/chemical synthesis , Amides/chemistry , Amines/chemical synthesis , Amines/chemistry , Dose-Response Relationship, Drug , Humans , Molecular Structure , Structure-Activity RelationshipABSTRACT
Small molecule modulators of GPR88 activity (agonists, antagonists, or modulators) are of interest as potential agents for the treatment of a variety of psychiatric disorders including schizophrenia. A series of phenylglycinol and phenylamine analogs have been prepared and evaluated for their GPR88 agonist activity and pharmacokinetic (PK) properties.
Subject(s)
Amines/pharmacology , Drug Design , Ethanolamines/pharmacology , Receptors, G-Protein-Coupled/agonists , Amines/chemical synthesis , Amines/chemistry , Dose-Response Relationship, Drug , Ethanolamines/chemical synthesis , Ethanolamines/chemistry , HEK293 Cells , Humans , Molecular Structure , Structure-Activity RelationshipABSTRACT
The conjugated entriyne natural product, (S)-(E)-15,16-dihydrominquartynoic acid (1), is synthesized in five linear steps and 30% overall yield from the known aldehyde 11. The key step is a one-pot in situ desilylation/Cadiot-Chodkiewicz coupling reaction affording the entriyne unit. The bromoalkyne 6 with an omega-carboxylic acid group was found to undergo a copper-catalyzed cross-coupling reaction producing the desired diyne intermediate 10, while the corresponding omega-ester bromoalkyne 14 failed to couple with triethylsilylacetylene under a variety of conditions.
Subject(s)
Alkynes/chemical synthesis , Antineoplastic Agents/chemical synthesis , Fatty Acids, Unsaturated/chemical synthesis , Molecular Structure , PolyynesABSTRACT
The conjugated tetraacetylenic natural product (S)-18-hydroxyminquartynoic acid (2) is synthesized in five linear steps and 17.7% overall yield from commercially available 1,2,5,6-O-diisopropylidene mannitol. The key step is a one-pot three-component Cadiot-Chodkiewicz reaction affording the tetrayne unit. The oxygen-substituted bromoalkyne 10 was found to react at a much faster rate than the non-oxygen-substituted bromoalkyne 6 in the key step. The undesired symmetric cross-coupling by 10 generates a symmetric tetrayne intermediate, which undergoes a nucleophilic addition by 1 equiv of ethylamine. This side reaction is suppressed by controlling the order and rate of addition of each component and by reducing the amount of ethylamine.