Search

Introduction: The serine/threonine kinase 17B (STK17B) is involved in setting the threshold for T cell activation and its absence sensitizes T cells to suboptimal stimuli. Consequently, STK17B represents an attractive potential target for cancer immunotherapy., Methods: To assess the potential of STK17B as an immuno-oncology target, we developed potent and selective tool compounds from starting points in Blueprint Medicines Corporation's proprietary kinase inhibitor library. To characterize these molecules, enzyme and cellular assays for STK17A and STK17B were established to drive chemistry optimization. Mass spectrometry-based phosphoproteomics profiling with tool inhibitors led to the identification of Ser19 on myosin light chain 2 as STK17B substrate, which is then developed into a flow cytometry-based pharmacodynamic readout of STK17B inhibition both in vitro and in vivo ., Results: In a mouse T cell activation assay, STK17B inhibitors demonstrated the ability to enhance interleukin-2 (IL-2) production. Similarly, treatment with STK17B inhibitors resulted in stronger cytokine secretion in human T cells activated using a T cell bispecific antibody. Subsequent chemistry optimization led to the identification of a highly selective and orally bioavailable tool compound, BLU7482. In vivo , STK17B inhibition led to dose-dependent modulation of myosin light chain 2 phosphorylation and enhanced priming of naïve T cells, as determined by upregulation of CD69, IL-2 and interferon-γ secretion. In line with increased T cell activation, treatment with STK17B inhibitor enhanced antitumor activity of anti-PD-L1 antibody in the MCA205 model., Conclusions: In summary, we successfully identified and optimized STK17B kinase inhibitors which led to increased T cell responses in vitro and in vivo . This allowed us to evaluate the potential of STK17B inhibition as an approach for cancer immunotherapy., Competing Interests: Authors FS, JEC, RC, CDS, JG, JLK, CK, KM, RM, EP, YT, TT, RW, RW, and MD were employed by the company Blueprint Medicines Corporation at the time of the study. FS, JG, RC, JK, CK, KM, EP, YT, RM, TT, and RW hold stocks and shares in Blueprint Medicines Corporation. Authors FR, JE, HF, LG, PJ, AM, UH, ST, MT, and JRB were employed by the company F. Hoffmann-La Roche Ltd. at the time of the study. FR and JRB hold stocks in F. Hoffmann-La Roche Ltd. JEC is currently affiliated with Reverie Labs, Cambridge, MA, USA. CDS is currently affiliated with Curie.Bio, Boston, MA, USA. NP is currently affiliated with ROME therapeutics, Boston, MA, USA. ST is currently affiliated with Altos Labs, Los Altos, CA, USA. RW is currently an independent consultant. MD is currently affiliated with Atavistik Bio, Cambridge, MA, USA. The authors declare that this research received funding from Blueprint Medicines Corporation and F. Hoffmann-La Roche Ltd. The sponsor was involved in the study design, collection, analysis, and interpretation of data, as well as data checking of information provided in the manuscript., (Copyright © 2024 Scheuplein, Renner, Campbell, Campbell, De Savi, Eckmann, Fischer, Ge, Green, Jakob, Kim, Kinkema, McGinn, Medina, Müller, Perez, Perola, Timsit, Traore, Hopfer, Tyanova, Tzouros, Wang, Woessner, Dorsch and Bischoff.)

A series of GPR119 agonists based on a 2,6-diazatricyclo[3.3.1.1∼3,7∼]decane ring system is described. Also provided is a detailed account of the development of a multigram scale synthesis of the diazatricyclic ring system, which was achieved using a Hofmann-Löffler-Freytag reaction as the key step. The basis for the use of this complex framework lies in an attempt to constrain one end of the molecule in the "agonist conformation" as was previously described for 3-oxa-7-aza-bicyclo[3.3.1]nonanes. Optimization of carbamate analogues of the diazatricylic compounds led to the identification of 32i as a potent agonist of the GPR119 receptor with low unbound human liver microsomal clearance. The use of an agonist response weighted ligand lipophilic efficiency (LLE) termed AgLLE is discussed along with the issues of applying efficiency measures to agonist programs. Ultimately, solubility limited absorption and poor exposure reduced further interest in these molecules.