Long-Acting Tumor-Activated Prodrug of a TGFßR Inhibitor.

Inhibition of TGFß signaling in concert with a checkpoint blockade has been shown to provide improved and durable antitumor immune response in mouse models. However, on-target adverse cardiovascular effects have limited the clinical use of TGFß receptor (TGFßR) inhibitors in cancer therapy. To restrict the activity of TGFßR inhibitors to tumor tissues and thereby widen the therapeutic index, a series of tumor-activated prodrugs of a selective small molecule TGFßR1 inhibitor 1 were prepared by appending 1 to a serine protease substrate and a half-life extension fatty acid carbon chain. The prodrugs were shown to be selectively metabolized in tumor tissues relative to the heart and blood and demonstrated a prolonged favorable increase in the tumor-to-heart ratio of the active drug in tissue distribution studies. Once-weekly administration of the most tissue-selective compound 10 provided anti-tumor efficacy comparable to the parent compound and reduced systemic exposure of the active drug.

Inhibition of Casein Kinase 2 Disrupts Differentiation of Myeloid Cells in Cancer and Enhances the Efficacy of Immunotherapy in Mice.

The role of myeloid cells as regulators of tumor progression that significantly impact the efficacy of cancer immunotherapies makes them an attractive target for inhibition. Here we explore the effect of a novel, potent, and selective inhibitor of serine/threonine protein kinase casein kinase 2 (CK2) on modulating myeloid cells in the tumor microenvironment. Although inhibition of CK2 caused only a modest effect on dendritic cells in tumor-bearing mice, it substantially reduced the amount of polymorphonuclear myeloid-derived suppressor cells and tumor-associated macrophages. This effect was not caused by the induction of apoptosis, but rather by a block of differentiation. Our results implicated downregulation of CCAAT-enhancer binding protein-α in this effect. Although CK2 inhibition did not directly affect tumor cells, it dramatically enhanced the antitumor activity of immune checkpoint receptor blockade using anti-CTLA-4 antibody. These results suggest a potential role of CK2 inhibitors in combination therapies against cancer.Significance: These findings demonstrate the modulatory effects of casein kinase 2 inhibitors on myeloid cell differentiation in the tumor microenvironment, which subsequently synergize with the antitumor effects of checkpoint inhibitor CTLA4. Cancer Res; 78(19); 5644-55. ©2018 AACR.

Structure-Based Design of Selective Janus Kinase 2 Imidazo[4,5-d]pyrrolo[2,3-b]pyridine Inhibitors.

Early hit to lead work on a pyrrolopyridine chemotype provided access to compounds with biochemical and cellular potency against Janus kinase 2 (JAK2). Structure-based drug design along the extended hinge region of JAK2 led to the identification of an important H-bond interaction with the side chain of Tyr 931, which improved JAK family selectivity. The 4,5-dimethyl thiazole analogue 18 demonstrated high levels of JAK family selectivity and was identified as a promising lead for the program.

Discovery of a Highly Selective JAK2 Inhibitor, BMS-911543, for the Treatment of Myeloproliferative Neoplasms.

JAK2 kinase inhibitors are a promising new class of agents for the treatment of myeloproliferative neoplasms and have potential for the treatment of other diseases possessing a deregulated JAK2-STAT pathway. X-ray structure and ADME guided refinement of C-4 heterocycles to address metabolic liability present in dialkylthiazole 1 led to the discovery of a clinical candidate, BMS-911543 (11), with excellent kinome selectivity, in vivo PD activity, and safety profile.

9H-Carbazole-1-carboxamides as potent and selective JAK2 inhibitors.

The discovery, synthesis, and characterization of 9H-carbazole-1-carboxamides as potent and selective ATP-competitive inhibitors of Janus kinase 2 (JAK2) are discussed. Optimization for JAK family selectivity led to compounds 14 and 21, with greater than 45-fold selectivity for JAK2 over all other members of the JAK kinase family.

Structural basis for CARM1 inhibition by indole and pyrazole inhibitors.

CARM1 (co-activator-associated arginine methyltransferase 1) is a PRMT (protein arginine N-methyltransferase) family member that catalyses the transfer of methyl groups from SAM (S-adenosylmethionine) to the side chain of specific arginine residues of substrate proteins. This post-translational modification of proteins regulates a variety of transcriptional events and other cellular processes. Moreover, CARM1 is a potential oncological target due to its multiple roles in transcription activation by nuclear hormone receptors and other transcription factors such as p53. Here, we present crystal structures of the CARM1 catalytic domain in complex with cofactors [SAH (S-adenosyl-L-homocysteine) or SNF (sinefungin)] and indole or pyazole inhibitors. Analysis of the structures reveals that the inhibitors bind in the arginine-binding cavity and the surrounding pocket that exists at the interface between the N- and C-terminal domains. In addition, we show using ITC (isothermal titration calorimetry) that the inhibitors bind to the CARM1 catalytic domain only in the presence of the cofactor SAH. Furthermore, sequence differences for select residues that interact with the inhibitors may be responsible for the CARM1 selectivity against PRMT1 and PRMT3. Together, the structural and biophysical information should aid in the design of both potent and specific inhibitors of CARM1.

Pyrrolo[1,2-f]triazines as JAK2 inhibitors: achieving potency and selectivity for JAK2 over JAK3.

SAR studies of pyrrolo[1,2-f]triazines as JAK2 inhibitors is presented. Achieving JAK2 inhibition selectively over JAK3 is discussed.

Benzo[d]imidazole inhibitors of Coactivator Associated Arginine Methyltransferase 1 (CARM1)--Hit to Lead studies.

Hit to Lead optimization and SAR development led to the identification of the potent and selective benzo[d]imidazole inhibitor (17b) of Co-activator Associated Arginine Methyltransferase (CARM1).

Optimization of pyrazole inhibitors of Coactivator Associated Arginine Methyltransferase 1 (CARM1).

Design, synthesis, and SAR development led to the identification of the potent, novel, and selective pyrazole based inhibitor (7f) of Coactivator Associated Arginine Methyltransferase (CARM1).

Pyrazole inhibitors of coactivator associated arginine methyltransferase 1 (CARM1).

This study reports the identification and Hits to Leads optimization of inhibitors of coactivator associated arginine methyltransferase (CARM1). Compound 7b is a potent, selective inhibitor of CARM1.

Core exploration in optimization of chemokine receptor CCR4 antagonists.

The design, synthesis, and SAR studies of 'core' variations led to identification of novel, selective, and potent small molecule antagonist (22) of the CC chemokine receptor-4 (CCR4) with improved in vitro activity and liability profile. Compound 22 was efficacious in a murine allergic inflammation model (ED50 approximately 10 mg/kg).

Antagonists of CCR4 as immunomodulatory agents.

The chemokine receptor CCR4 is broadly expressed on cells of the immune system. It is known to play a central role in T cell migration to the thymus, and T cell maturation and education. In addition, CCR4 is known to modulate T cell migration to several sites of inflammation in the body, including the skin, and lungs. It is best known as a drug target for airway inflammation and atopic dermatitis, but cells expressing CCR4 are found in many inflammatory diseases. CCR4 small molecule antagonists have not yet reached the clinic, but at least one has been validated in an in vivo model. Here we review the current status of structurally novel CCR4 receptor antagonists.

Optimization of CCR4 antagonists: side-chain exploration.

The design, synthesis, and activity of novel and selective small molecule antagonists of the CC chemokine receptor-4 (CCR4) are presented. Compound 8c was efficacious in a murine allergic inflammation model (ED(50) 30 mg/kg).

Identification of chemokine receptor CCR4 antagonist.

The present study reports the identification and hits to leads optimization of chemokine receptor CCR4 antagonists. Compound 12 is a high affinity, non-cytotoxic antagonist of CCR4 that blocks the functional activity mediated by the receptor.

Identification of a potent and rapidly reversible inhibitor of the 20S-proteasome.

Synthesis and in vitro characterization of novel, lactam boronic acid based, selective, and rapidly reversible inhibitor 14 of the 20S-proteasome is presented.

Diaminopyrimidine and diaminopyridine 5-HT7 ligands.

The present studies have identified a series of diaminopyrimidines and diaminopyridines as novel 5-HT(7) receptor ligands. Three regiosiomeric classes of pyrimidines and four regioisomeric classes of pyridines were synthesized and analyzed for binding to the 5-HT(7) receptor. The 5-HT(7) binding affinities of different regioisomers show clearly the structure-activity relationship with position of ring nitrogens.