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Identification and characterization of an atypical Gαs-biased β 2AR agonist that fails to evoke airway smooth muscle cell tachyphylaxis. Proc Natl Acad Sci U S A 2021; 118:2026668118. [PMID: 34857633 PMCID: PMC8670521 DOI: 10.1073/pnas.2026668118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 12/23/2022] Open
Abstract
We sought β2AR agonists for treating obstructive lung diseases such as asthma, in which this receptor relaxes airway smooth muscle (ASM) cells and opens airways. Agonists favoring Gs coupling (leads to airway relaxation) compared with activating β-arrestin (limits effectiveness due to receptor desensitization) were pursued in a 40-million-compound screening library. Of several agonists identified, one was apparently biased away from β-arrestin. Agonist–receptor–G protein modeling revealed different receptor interactions compared with other agonists. The favorable effects of the apparent biasing with this agonist were demonstrated in a physiologic system (ASM relaxation). These studies point to a different structural class of β-agonists that might be used to treat obstructive lung diseases without the adverse effects associated with tachyphylaxis. G protein–coupled receptors display multifunctional signaling, offering the potential for agonist structures to promote conformational selectivity for biased outputs. For β2-adrenergic receptors (β2AR), unbiased agonists stabilize conformation(s) that evoke coupling to Gαs (cyclic adenosine monophosphate [cAMP] production/human airway smooth muscle [HASM] cell relaxation) and β-arrestin engagement, the latter acting to quench Gαs signaling, contributing to receptor desensitization/tachyphylaxis. We screened a 40-million-compound scaffold ranking library, revealing unanticipated agonists with dihydroimidazolyl-butyl-cyclic urea scaffolds. The S-stereoisomer of compound C1 shows no detectable β-arrestin engagement/signaling by four methods. However, C1-S retained Gαs signaling—a divergence of the outputs favorable for treating asthma. Functional studies with two models confirmed the biasing: β2AR-mediated cAMP signaling underwent desensitization to the unbiased agonist albuterol but not to C1-S, and desensitization of HASM cell relaxation was observed with albuterol but not with C1-S. These HASM results indicate biologically pertinent biasing of C1-S, in the context of the relevant physiologic response, in the human cell type of interest. Thus, C1-S was apparently strongly biased away from β-arrestin, in contrast to albuterol and C5-S. C1-S structural modeling and simulations revealed binding differences compared with unbiased epinephrine at transmembrane (TM) segments 3,5,6,7 and ECL2. C1-S (R2 = cyclohexane) was repositioned in the pocket such that it lost a TM6 interaction and gained a TM7 interaction compared with the analogous unbiased C5-S (R2 = benzene group), which appears to contribute to C1-S biasing away from β-arrestin. Thus, an agnostic large chemical-space library identified agonists with receptor interactions that resulted in relevant signal splitting of β2AR actions favorable for treating obstructive lung disease.
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Yan Y, Zhang Y, Li M, Zhang Y, Zhang X, Zhang X, Xu Y, Wei W, Wang J, Xu X, Song Q, Zhao C. C644-0303, a small-molecule inhibitor of the Wnt/β-catenin pathway, suppresses colorectal cancer growth. Cancer Sci 2021; 112:4722-4735. [PMID: 34431598 PMCID: PMC8586673 DOI: 10.1111/cas.15118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/15/2022] Open
Abstract
The Wnt/β‐catenin signaling pathway plays an important role in tissue homeostasis, and its malignant activation is closely related to the occurrence and development of many cancers, especially colorectal cancer with adenomatous polyposis coli (APC) and CTNNB1 mutations. By applying a TCF/lymphoid‐enhancing factor (LEF) luciferase reporter system, the high‐throughput screening of 18 840 small‐molecule compounds was performed. A novel scaffold compound, C644‐0303, was identified as a Wnt/β‐catenin signaling inhibitor and exhibited antitumor efficacy. It inhibited both constitutive and ligand activated Wnt signals and its downstream gene expression. Functional studies showed that C644‐0303 causes cell cycle arrest, induces apoptosis, and inhibits cancer cell migration. Moreover, transcription factor array indicated that C644‐0303 could suppress various tumor‐promoting transcription factor activities in addition to Wnt/β‐catenin. Finally, C644‐0303 suppressed tumor spheroidization in a 3‐dimensional cell culture model and inhibited xenograft tumor growth in mice. In conclusion, we report a novel structural small molecular inhibitor targeting the Wnt/β‐catenin signaling pathway that has therapeutic potential for colorectal cancer treatment.
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Affiliation(s)
- Yu Yan
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Yidan Zhang
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Mengyuan Li
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Yazhuo Zhang
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Xinxin Zhang
- Innovation Platform of Marine Drug Screening & Evaluation, Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiaonan Zhang
- Innovation Platform of Marine Drug Screening & Evaluation, Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yuting Xu
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Wei Wei
- School of Life Science, Lanzhou University, Lanzhou, China
| | - Jie Wang
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Xiaohan Xu
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Qiaoling Song
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Innovation Platform of Marine Drug Screening & Evaluation, Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Chenyang Zhao
- School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Innovation Platform of Marine Drug Screening & Evaluation, Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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Kellici TF, Pilka ES, Bodkin MJ. Small-molecule modulators of serine protease inhibitor proteins (serpins). Drug Discov Today 2020; 26:442-454. [PMID: 33259801 DOI: 10.1016/j.drudis.2020.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/11/2020] [Accepted: 11/10/2020] [Indexed: 02/06/2023]
Abstract
Serine protease inhibitors (serpins) are a large family of proteins that regulate and control crucial physiological processes, such as inflammation, coagulation, thrombosis and thrombolysis, and immune responses. The extraordinary impact that these proteins have on numerous crucial pathways makes them an attractive target for drug discovery. In this review, we discuss recent advances in research on small-molecule modulators of serpins, examine their mode of action, analyse the structural data from crystallised protein-ligand complexes, and highlight the potential obstacles and possible therapeutic perspectives. The application of in silico methods for rational drug discovery is also summarised. In addition, we stress the need for continued research in this field.
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