Biology subjects

Sheffler, D. J.

Publications and source records attributed to Sheffler, D. J..

3 recordsLinked to original sources

bioRxiv2026

A phytocannabinoid-sensitive phosphorylation switch converts endocannabinoids into alternative lipid GPCR activators

Abstract: Endocannabinoids (eCBs) like anandamide and 2-arachidonoylglycerol are endogenous lipid ligands for CB1 and CB2 G protein-coupled receptors (GPCRs). Here, we show that phosphorylation of biologically important anandamide generates naturally occurring anandamide phosphate (AEAp), which switches GPCR ligand specificity to lysophosphatidic acid (LPA) receptors (LPARs) and the primate-specific bile acid sensory receptor MRGPRX4. The kinase responsible for anandamide phosphorylation was identified asdiacylglycerol kinase (DGK) theta (DGKq or DGKQ) using activity-guided brain fractionation, inhibitor profiling, recombinant reconstitution, and DGK isozyme screening. DGKQ showed noncanonical biphasic lipid kinetics and was inhibited by phytocannabinoids, most notably tetrahydrocannabinolic acid. Thus, eCBs are not only cannabinoid receptor ligands but also enzymatically adaptable lipid signals activating LPARs and MRGPRX4, thus linking metabolism of the distinct lipid LPA with Cannabis pharmacology.

biochemistry↗

bioRxiv2025

ULK1/2 Inhibitors that Degrade ATG13 Effectively Target KRAS-Mutant Cancers

KRAS mutations drive tumorigenesis in multiple cancer types, including lung and pancreatic cancer. Autophagy is a cell survival pathway that supports tumor growth under metabolic stress and has been proposed to be a potential therapeutic avenue specifically in KRAS mutant cancers. The Unc-51-like ATG-activating kinases 1 and 2 (ULK) initiate the earliest regulated steps of autophagy and are the only protein kinases in the canonical autophagy pathway, thus making them attractive therapeutic targets for KRAS mutant tumors. We show here that genetic depletion of ULK1 or ATG13, core components of the ULK1 complex, in KRAS mutant lung and pancreatic cancer cell lines results in growth inhibition. Previously, we developed small molecule ULK1 inhibitors that not only inhibit ULK kinase activity but also induced the degradation of other core members of the ULK complex including ATG101 and ATG13. Therefore, we developed a high-throughput screening (HTS) assay in which ATG13 was HiBiT-tagged in KRAS mutant lung cancer cells to evaluate ULK inhibitors for ATG13 degradation. Using this approach, we discovered a lead ULK inhibitor, SBP-1750, that potently inhibited ULK activity, promoted robust ATG13 degradation, impaired ATG, and induced KRAS mutant cancer cell death. Studies in a KRAS-mutant orthotopic syngeneic pancreatic cancer model show that oral treatment with SBP-1750 significantly reduced tumor growth. Pharmacokinetic analysis of SBP-1750 indicates favorable drug exposure and pharmacodynamic analysis confirms ATG13 degradation in vivo, mirroring in vitro results. Finally, immunohistochemical staining of orthotopic pancreatic tumors reveals a significant increase in CD4 and CD8 T cell infiltration upon treatment, suggesting that SBP-1750 enhances anti-tumor immunity. These findings support further development of SBP-1750 as a novel ATG-targeting cancer therapy.

cancer biology↗

bioRxiv2025

Synthesis and Characterization of ULK1/2 Kinase Inhibitors that Inhibit Autophagy and Upregulate Expression of Major Histocompatibility Complex I for the Treatment of Non-Small Cell Lung Cancer

Autophagy inhibition represents a promising therapeutic approach for the management of various cancers including non-small cell lung cancer (NSCLC). We previously reported SBP-7455, a dual inhibitor of unc-51-like kinase 1 (ULK1) and its homologue ULK2, and described its effects on triple-negative breast cancer (TNBC) cells. Herein we report the design, synthesis, and characterization of SBP-5147 and SBP-7501, two new dual ULK1/2 inhibitors that are cytotoxic against NSCLC cells, inhibit autophagic flux in A549 cells, and present greater oral exposure than SBP-7455 at a lower dose. In addition, SBP-5147 effectively modulates autophagy and increases the expression of major histocompatibility complex (MHC) class I in NSCLC cells, which may support the rationale for ULK1/2 inhibition as a strategy to overcome resistance to immunotherapy. Together these data support the use of ULK inhibitors as part of a cancer treatment strategy, both as a single agent as well as in combination with current therapies.

cancer biology↗