Discovery of a broad spectrum antiproliferative agent with selectivity for DDR1 kinase: cell line-based assay, kinase panel, molecular docking, and toxicity studies

Identification of Ureidocoumarin-Based Selective Discoidin Domain Receptor 1 (DDR1) Inhibitors via Drug Repurposing Approach, Biological Evaluation, and In Silico Studies

Discoidin domain receptor 1 (DDR1) kinase has emerged as a promising target for cancer therapy, and selective DDR1 inhibitors have shown promise as effective therapeutic candidates. Herein, we have identified the first coumarin-based selective DDR1 inhibitors via repurposing of a recent series of carbonic anhydrase inhibitors. Among these, ureidocoumarins 3a, 3i, and 3q showed the best DDR1 inhibitory activities. The m-trifluoromethoxy phenyl member 3q potently inhibited DDR1 with an IC50 of 191 nM, while it showed less inhibitory activity against DDR2 (IC50 = 5080 nM). 3q also exhibited favorable selectivity in a screening platform with 23 common off-target kinases, including BCR-ABL. In the cellular context, 3q showed moderate antiproliferative effects, while 3i, with the third rank in DDR1 inhibition, exerted the best anticancer activity with sub-micromolar GI50 values over certain DDR1-dependent cell lines. Molecular docking and MD simulations disclosed the putative binding mode of this coumarin chemotype and provided insights for further optimization of this scaffold. The present findings collectively supported the potential improvement of ureidocoumarins 3i and 3q for cancer treatment.

Research progress of DDR1 inhibitors in the treatment of multiple human diseases

Discoidin domain receptor 1 (DDR1) is a collagen-activated receptor tyrosine kinase (RTK) and plays pivotal roles in regulating cellular functions such as proliferation, differentiation, invasion, migration, and matrix remodeling. DDR1 is involved in the occurrence and progression of many human diseases, including cancer, fibrosis, and inflammation. Therefore, DDR1 represents a highly promising therapeutic target. Although no selective small-molecule inhibitors have reached clinical trials to date, many molecules have shown therapeutic effects in preclinical studies. For example, BK40143 has demonstrated significant promise in the therapy of neurodegenerative diseases. In this context, our perspective aims to provide an in-depth exploration of DDR1, encompassing its structure characteristics, biological functions, and disease relevance. Furthermore, we emphasize the importance of understanding the structure-activity relationship of DDR1 inhibitors and highlight the unique advantages of dual-target or multitarget inhibitors. We anticipate offering valuable insights into the development of more efficacious DDR1-targeted drugs.

Discovery of novel (E)-1-methyl-9-(3-methylbenzylidene)-6,7,8,9-tetrahydropyrazolo[3,4-d]pyrido[1,2-a]pyrimidin-4(1H)-one as DDR2 kinase inhibitor: Synthesis, molecular docking, and anticancer properties

We report the synthesis, molecular docking and anticancer properties of the novel compound (E)-1-methyl-9-(3-methylbenzylidene)-6,7,8,9-tetrahydropyrazolo[3,4-d]pyrido[1,2-a]pyrimidin-4(1H)-one (PP562). PP562 was screened against sixteen human cancer cell lines and exhibited excellent antiproliferative activity with IC₅₀ values ranging from 0.016 to 5.667 μM. Experiments were carried out using the target PP562 at a single dose of 1.0 μM against a kinase panel comprising 100 different enzymes. A plausible binding mechanism for PP562 inhibition of DDR2 was determined using molecular dynamic analysis. The effect of PP562 on cell proliferation was also examined in cancer cell models with both high and low expression of the DDR2 gene; PP562 inhibition of high-expressing cells was more prominent than that for low expressing cells. PP562 also exhibits excellent anticancer potency toward the HGC-27 gastric cancer cell line. In addition, PP562 inhibits colony formation, cell migration, and adhesion, induces cell cycle arrest at the G2/M phase, and affects ROS generation and cell apoptosis. After DDR2 gene knockdown, the antitumor effects of PP562 on tumor cells were significantly impaired. These results suggested that PP562 might exert its inhibitory effect on HCG-27 proliferation through the DDR2 target.

Discoidin domain receptor 1 may be involved in biological barrier homeostasis

WHAT IS KNOWN AND OBJECTIVE

Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase involved in the pathological processes of several diseases, such as keloid formation, renal fibrosis, atherosclerosis, tumours, and inflammatory processes. The biological barrier is the first line of defence against pathogens, and its disruption is closely related to diseases. In this review, we attempt to elucidate the relationship between DDR1 and the biological barrier, explore the potential biological value of DDR1, and review the current research status and clinical potential of DDR1-selective inhibitors.

METHODS

We conducted an extensive literature search on PubMed to collect studies on the relevance of DDR1 to biological barriers and DDR1-selective inhibitors. With these studies, we explored the relationship between DDR1 and biological barriers and briefly reviewed representative DDR1-selective inhibitors that have been reported in recent years.

RESULTS AND DISCUSSION

First, the review of the potential mechanisms by which DDR1 regulates biological barriers, including the epithelial, vascular, glomerular filtration, blood-labyrinth, and blood-brain barriers. In the body, DDR1 dysfunction and aberrant expression may be involved in the homeostasis of the biological barrier. Secondly, the review of DDR1 inhibitors reported in recent years shows that DDR1-targeted inhibition is an attractive and promising pharmacological intervention.

WHAT IS NEW AND CONCLUSIONS

This review shows that DDR1 is involved in various physiological and pathological processes and in the regulation of biological barrier homeostasis. However, studies on DDR1 and biological barriers are still scarce, and further studies are needed to elucidate their specific mechanisms. The development of targeted inhibitors provides a new direction and idea to study the mechanism of DDR1.

Identification of novel discoidin domain receptor 1 (DDR1) inhibitors using E-pharmacophore modeling, structure-based virtual screening, molecular dynamics simulation and MM-GBSA approaches

Dysregulation of the discoidin domain receptor (DDR1), a collagen-activated receptor tyrosine kinase, has been linked to several human cancer diseases including non-small cell lung carcinoma (NSCLC), ovarian cancer, glioblastoma, and breast cancer, in addition to several inflammatory and neurological conditions. Although there are some selective DDR1 inhibitors that have been discovered during the last two decades, a combination of elevated cytotoxicity, kinome selectivity and/or poor DMPK profile has prevented more in-depth studies from being performed. As such, no DDR1 inhibitor has reached clinical investigation to date, forming an urgent need to develop specific DDR1 inhibitor(s) using various drug discovery means. However, the recent discovery of VU6015929, a potent and selective DDR1 kinase inhibitor, with enhanced physiochemical and DMPK properties in addition to its clean kinome profile marked a milestone in the development of DDR1 inhibitors. Herein, VU6015929 was used to construct a 3D e-pharmacophore model which was validated via calculating the difference of score between the active compounds and decoys. The validated e-pharmacophore model was then utilized to screen 20 million drug-like compounds obtained from the freely accessible Zinc database. The generated hits were ranked using high throughput virtual screening technique (HTVS), and the top 8 small molecules were subjected to a molecular docking study and MM-GBSA calculations. Protein-ligand complexes of compounds 1, 2, 3 and the standard compound (VU6015929) were performed for 100 ns and compared with the DDR1 unbound protein state and the DDR1 bound to a co-crystallized ligand. The molecular docking, MD and MM-GBSA outputs revealed compounds 1-3 as potential DDR1 inhibitors, with compound 2 displaying superior binding affinity, comparable binding stability and average binding free energy for the ligand-enzyme complex compared to VU6015929.

Inhibitors of Discoidin Domain Receptor (DDR) Kinases for Cancer and Inflammation

The discoidin domain receptor tyrosine kinases DDR1 and DDR2 are distinguished from other kinase enzymes by their extracellular domains, which interact with collagen rather than with peptidic growth factors, before initiating signaling via tyrosine phosphorylation. They share significant sequence and structural homology with both the c-Kit and Bcr-Abl kinases, and so many inhibitors of those kinases are also effective. Nevertheless, there has been an extensive research effort to develop potent and specific DDR inhibitors. A key interaction for many of these compounds is H-bonding to Met-704 in a hydrophobic pocket of the DDR enzyme. The most widespread use of DDR inhibitors has been for cancer therapy, but they have also shown effectiveness in animal models of inflammatory conditions such as Alzheimer's and Parkinson's diseases, and in chronic renal failure and glomerulonephritis.

Scaffold Repurposing of In-House Small Molecule Candidates Leads to Discovery of First-in-Class CDK-1/HER-2 Dual Inhibitors: In Vitro and In Silico Screening

Recently, multitargeted drugs are considered a potential approach in treating cancer. In this study, twelve in-house indole-based derivatives were preliminary evaluated for their inhibitory activities over VEGFR-2, CDK-1/cyclin B and HER-2. Compound 15l showed the most inhibitory activities among the tested derivatives over CDK-1/cyclin B and HER-2. Compound 15l was tested for its selectivity in a small kinase panel. It showed dual selectivity for CDK-1/cyclin B and HER-2. Moreover, in vitro cytotoxicity assay was assessed for the selected series against nine NCI cell lines. Compound 15l showed the most potent inhibitory activities among the tested compounds. A deep in silico molecular docking study was conducted for compound 15l to identify the possible binding modes into CDK-1/cyclin B and HER-2. The docking results revealed that compound 15l displayed interesting binding modes with the key amino acids in the binding sites of both kinases. In vitro and in silico studies demonstrate the indole-based derivative 15l as a selective dual CDK-1 and HER-2 inhibitor. This emphasizes a new challenge in drug development strategies and signals a significant milestone for further structural and molecular optimization of these indole-based derivatives in order to achieve a drug-like property.

Development of New Meridianin/Leucettine-Derived Hybrid Small Molecules as Nanomolar Multi-Kinase Inhibitors with Antitumor Activity

Although the sea ecosystem offers a broad range of bioactivities including anticancer, none of the FDA-approved antiproliferative protein kinase inhibitors are derived from a marine source. In a step to develop new marine-inspired potent kinase inhibitors with antiproliferative activities, a new series of hybrid small molecules (5a–5g) was designed and synthesized based on chemical moieties derived from two marine natural products (Meridianin E and Leucettamine B). Over a panel of 14 cancer-related kinases, a single dose of 10 µM of the parent hybrid 5a possessing the benzo[d][1,3]dioxole moiety of Leucettamine B was able to inhibit the activity of FMS, LCK, LYN, and DAPK1 kinases with 82.5 ± 0.6, 81.4 ± 0.6, 75.2 ± 0.0, and 55 ± 1.1%, respectively. Further optimization revealed the most potent multiple kinase inhibitor of this new series (5g) with IC₅₀ values of 110, 87.7, and 169 nM against FMS, LCK, and LYN kinases, respectively. Compared to imatinib (FDA-approved multiple kinase inhibitor), compound 5g was found to be ~ 9- and 2-fold more potent than imatinib over both FMS and LCK kinases, respectively. In silico docking simulation models of the synthesized compounds within the active site of FMS, LCK, LYN, and DAPK1 kinases offered reasonable explanations of the elicited biological activities. In an in vitro anticancer assay using a library of 60 cancer cell lines that include blood, lung, colon, CNS, skin, ovarian, renal, prostate, and breast cancers, it was found that compound 5g was able to suppress 60 and 70% of tumor growth in leukemia SR and renal RXF 393 cell lines, respectively. Moreover, an ADME study indicated a suitable profile of compound 5g concerning cell permeability and blood-brain barrier (BBB) impermeability, avoiding possible CNS side effects. Accordingly, compound 5g is reported as a potential lead towards novel antiproliferative marine-derived kinase modulators.

New horizons in drug discovery of lymphocyte-specific protein tyrosine kinase (Lck) inhibitors: a decade review (2011-2021) focussing on structure-activity relationship (SAR) and docking insights

Lymphocyte-specific protein tyrosine kinase (Lck), a non-receptor Src family kinase, has a vital role in various cellular processes such as cell cycle control, cell adhesion, motility, proliferation, and differentiation. Lck is reported as a key factor regulating the functions of T-cell including the initiation of TCR signalling, T-cell development, in addition to T-cell homeostasis. Alteration in expression and activity of Lck results in numerous disorders such as cancer, asthma, diabetes, rheumatoid arthritis, atherosclerosis, and neuronal diseases. Accordingly, Lck has emerged as a novel target against different diseases. Herein, we amass the research efforts in literature and pharmaceutical patents during the last decade to develop new Lck inhibitors. Additionally, structure-activity relationship studies (SAR) and docking models of these new inhibitors within the active site of Lck were demonstrated offering deep insights into their different binding modes in a step towards the identification of more potent, selective, and safe Lck inhibitors.

The Journey of DDR1 and DDR2 Kinase Inhibitors as Rising Stars in the Fight Against Cancer

Discoidin domain receptor (DDR) is a collagen-activated receptor tyrosine kinase that plays critical roles in regulating essential cellular processes such as morphogenesis, differentiation, proliferation, adhesion, migration, invasion, and matrix remodeling. As a result, DDR dysregulation has been attributed to a variety of human cancer disorders, for instance, non-small-cell lung carcinoma (NSCLC), ovarian cancer, glioblastoma, and breast cancer, in addition to some inflammatory and neurodegenerative disorders. Since the target identification in the early 1990s to date, a lot of efforts have been devoted to the development of DDR inhibitors. From a medicinal chemistry perspective, we attempted to reveal the progress in the development of the most promising DDR1 and DDR2 small molecule inhibitors covering their design approaches, structure-activity relationship (SAR), biological activity, and selectivity.

Effects of a Novel Thiadiazole Derivative with High Anticancer Activity on Cancer Cell Immunogenic Markers: Mismatch Repair System, PD-L1 Expression, and Tumor Mutation Burden

Microsatellite instability (MSI), tumor mutation burden (TMB), and programmed cell death ligand-1 (PD-L1) are particularly known as immunotherapy predictive biomarkers. MSI and TMB are closely related to DNA mismatch repair (MMR) pathway functionality, while the PD-L1 checkpoint mediates cancer cell evasion from immune surveillance via the PD-L1/PD-1 axis. Among all the novel triazolo[3,4-b]thiadiazole derivatives, the compound KA39 emerged as the most potent anticancer agent. In the present study, potential alterations in MSI, TMB, and/or PD-L1 expression upon cell treatment with KA39 are explored. We tested three MMR-deficient (DLD-1, LS174T, and DU-145) and two MMR-proficient (HT-29 and PC-3) human cancer cell lines. Our findings support KA39-induced PD-L1 overexpression in all cancer cell lines, although the most outstanding increase was observed in MMR-proficient HT-29 cells. MSI analysis showed that KA39 affects the MMR system, impairing its recognition or repair activity, particularly in MMR-deficient DLD-1 and DU-145 cells, enhancing oligonucleotide production. There were no remarkable alterations in the TMB between untreated and treated cells, indicating that KA39 does not belong to mutagenic agents. Taking together the significant in vitro anticancer activity with PD-L1 upregulation and MSI increase, KA39 should be investigated further for its implication in chemo-immunotherapy of cancer.

The Mitochondrial mitoNEET Ligand NL-1 Is Protective in a Murine Model of Transient Cerebral Ischemic Stroke

PURPOSE

Therapeutic strategies to treat ischemic stroke are limited due to the heterogeneity of cerebral ischemic injury and the mechanisms that contribute to the cell death. Since oxidative stress is one of the primary mechanisms that cause brain injury post-stroke, we hypothesized that therapeutic targets that modulate mitochondrial function could protect against reperfusion-injury after cerebral ischemia, with the focus here on a mitochondrial protein, mitoNEET, that modulates cellular bioenergetics.

METHOD

In this study, we evaluated the pharmacology of the mitoNEET ligand NL-1 in an in vivo therapeutic role for NL-1 in a C57Bl/6 murine model of ischemic stroke.

RESULTS

NL-1 decreased hydrogen peroxide production with an IC50 of 5.95 μM in neuronal cells (N2A). The in vivo activity of NL-1 was evaluated in a murine 1 h transient middle cerebral artery occlusion (t-MCAO) model of ischemic stroke. We found that mice treated with NL-1 (10 mg/kg, i.p.) at time of reperfusion and allowed to recover for 24 h showed a 43% reduction in infarct volume and 68% reduction in edema compared to sham-injured mice. Additionally, we found that when NL-1 was administered 15 min post-t-MCAO, the ischemia volume was reduced by 41%, and stroke-associated edema by 63%.

CONCLUSION

As support of our hypothesis, as expected, NL-1 failed to reduce stroke infarct in a permanent photothrombotic occlusion model of stroke. This report demonstrates the potential therapeutic benefits of using mitoNEET ligands like NL-1 as novel mitoceuticals for treating reperfusion-injury with cerebral stroke.

The Yin and Yang of Discoidin Domain Receptors (DDRs): Implications in Tumor Growth and Metastasis Development

Simple Summary

The tumor microenvironment plays an important role in tumor development and metastasis. Collagens are major components of the extracellular matrix and can influence tumor development and metastasis by activating discoidin domain receptors (DDRs). This work shows the different roles of DDRs in various cancers and highlights the complexity of anti-DDR therapies in cancer treatment.

Abstract

The tumor microenvironment is a complex structure composed of the extracellular matrix (ECM) and nontumoral cells (notably cancer-associated fibroblasts (CAFs) and immune cells). Collagens are the main components of the ECM and they are extensively remodeled during tumor progression. Some collagens are ligands for the discoidin domain receptor tyrosine kinases, DDR1 and DDR2. DDRs are involved in different stages of tumor development and metastasis formation. In this review, we present the different roles of DDRs in these processes and discuss controversial findings. We conclude by describing emerging DDR inhibitory strategies, which could be used as new alternatives for the treatment of patients.

Anticancer Activity of Triazolo-Thiadiazole Derivatives and Inhibition of AKT1 and AKT2 Activation

The fusion of 1,2,4-triazole and 1,3,4-thiadiazole rings results in a class of heterocycles compounds with an extensive range of pharmacological properties. A series of 1,2,4-triazolo[3,4-b]-1,2,4-thiadiazoles was synthesized and tested for its enzyme inhibition potential and anticancer activity. The results show that 1,2,4-triazolo[3,4-b]-1,2,4-thiadiazoles display potent anticancer properties in vitro against a panel of cancer cells and in vivo efficacy in HT-29 human colon tumor xenograft in CB17 severe combined immunodeficient (SCID) mice. Preliminary mechanistic studies revealed that KA25 and KA39 exhibit time- and concentration-dependent inhibition of Akt Ser-473 phosphorylation. Molecular modeling experiments indicated that 1,2,4-triazolo[3,4-b]-1,2,4-thiadiazoles bind well to the ATP binding site in Akt1 and Akt2. The low acute toxicity combined with in vitro and in vivo anticancer activity render triazolo[3,4-b]thiadiazoles KA25, KA26, and KA39 promising cancer therapeutic agents.

Discoidin domain receptors orchestrate cancer progression: A focus on cancer therapies

Discoidin domain receptors (DDR), including DDR1 and DDR2, are special types of the transmembrane receptor tyrosine kinase superfamily. DDR are activated by binding to the triple-helical collagen and, in turn, DDR can activate signal transduction pathways that regulate cell-collagen interactions involved in multiple physiological and pathological processes such as cell proliferation, migration, apoptosis, and cytokine secretion. Recently, DDR have been found to contribute to various diseases, including cancer. In addition, aberrant expressions of DDR have been reported in various human cancers, which indicates that DDR1 and DDR2 could be new targets for cancer treatment. Considerable effort has been made to design DDR inhibitors and several molecules have shown therapeutic effects in pre-clinical models. In this article, we review the recent literature on the role of DDR in cancer progression, the development status of DDR inhibitors, and the clinical potential of targeting DDR in cancer therapies.

Structure Activity Relationship of Key Heterocyclic Anti-Angiogenic Leads of Promising Potential in the Fight against Cancer

Pathological angiogenesis is a hallmark of cancer; accordingly, a number of anticancer FDA-approved drugs act by inhibiting angiogenesis via different mechanisms. However, the development process of the most potent anti-angiogenics has met various hurdles including redundancy, multiplicity, and development of compensatory mechanisms by which blood vessels are remodeled. Moreover, identification of broad-spectrum anti-angiogenesis targets is proved to be required to enhance the efficacy of the anti-angiogenesis drugs. In this perspective, a proper understanding of the structure activity relationship (SAR) of the recent anti-angiogenics is required. Various anti-angiogenic classes have been developed over the years; among them, the heterocyclic organic compounds come to the fore as the most promising, with several drugs approved by the FDA. In this review, we discuss the structure–activity relationship of some promising potent heterocyclic anti-angiogenic leads. For each lead, a molecular modelling was also carried out in order to correlate its SAR and specificity to the active site. Furthermore, an in silico pharmacokinetics study for some representative leads was presented. Summarizing, new insights for further improvement for each lead have been reviewed.

3,6-Disubstituted 1,2,4-Triazolo[3,4-b]Thiadiazoles with Anticancer Activity Targeting Topoisomerase II Alpha

BACKGROUND

Topoisomerase IIα (topIIα) maintains the topology of DNA in order to ensure the proper functioning of numerous DNA processes. Inhibition of topIIα leads to the killing of cancer cells thus constituting such inhibitors as useful tools in cancer therapeutics. Triazolo[3,4-b]thiadiazole derivatives are known for their wide range of pharmacological activities while previous studies have documented their in vitro anticancer activity. The purpose of the current study was to investigate if these chemical compounds can act as topIIα inhibitors in cell-free and cell-based systems.

MATERIALS AND METHODS

The MTT assay was performed in DLD-1, HT-29, and LoVo cancer cells so as to evaluate the antiproliferative activity of KA25, KA26, and KA39 triazolo[3,4-b]thiadiazole derivatives. The KA39 compound was tested as a potential topIIα inhibitor using the plasmid-based topoisomerase II drug screening kit. The inhibitory effect of the three derivatives on topIIα phosphorylation was studied in HT-29 and LoVo cancer cells according to Human Phospho-TOP2A/Topoisomerase II Alpha Cell-Based Phosphorylation ELISA Kit. Moreover, flow cytometry was utilized in order to explore apoptotic induction and cell cycle growth arrest, upon treatment with KA39, in DLD-1 and HT-29 cells, respectively. In silico studies were also carried out for further investigation.

RESULTS

All three triazolo[3,4-b]thiadiazole derivatives showed an in vitro antiproliferative effect with the KA39 compound being the most potent one. Our results indicated that KA39 induced both early and late apoptosis as well as cell cycle growth arrest in S phase. In addition, the compound blocked the relaxation of supercoiled DNA while it also inhibited topIIα phosphorylation (upon treatment; P<0.001).

CONCLUSION

Among the three triazolo[3,4-b]thiadiazole derivatives, KA39 was shown to be the most potent anticancer agent and catalytic inhibitor of topIIα phosphorylation as well.

Discoidin domain receptors: A promising target in melanoma

The discoidin domain receptor 1 (DDR1) is a member of the receptor tyrosine kinase family that signals in response to collagen and that has been implicated in cancer progression. In the present study, we investigated the expression and role of DDR1 in human melanoma progression. Immunohistochemical staining of human melanoma specimens (n = 52) shows high DDR1 expression in melanoma lesions that correlates with poor prognosis. DDR1 expression was associated with the clinical characteristics of Clark level and ulceration and with BRAF mutations. Downregulation of DDR1 by small interfering RNA (siRNA) in vitro inhibited melanoma cells malignant properties, migration, invasion, and survival in several human melanoma cell lines. A DDR tyrosine kinase inhibitor (DDR1-IN-1) significantly inhibited melanoma cell proliferation in vitro, and ex vivo and in tumor xenografts, underlining the promising potential of DDR1 inhibition in melanoma.

Multitasking discoidin domain receptors are involved in several and specific hallmarks of cancer

Discoidin domain receptors, DDR1 and DDR2, are two members of collagen receptor family that belong to tyrosine kinase receptor subgroup. Unlike other matrix receptor-like integrins, these collagen receptors have not been extensively studied. However, more and more studies are focusing on their involvement in cancer. These two receptors are present in several subcellular localizations such as intercellular junction or along type I collagen fibers. Consequently, they are involved in multiple cellular functions, for instance, cell cohesion, proliferation, adhesion, migration and invasion. Furthermore, various signaling pathways are associated with these multiple functions. In this review, we highlight and characterize hallmarks of cancer in which DDRs play crucial roles. We discuss recent data from studies that demonstrate the involvement of DDRs in tumor proliferation, cancer mutations, drug resistance, inflammation, neo-angiogenesis and metastasis. DDRs could be potential targets in cancer and we conclude this review by discussing the different ways to inhibits them.

Tetrahydroisoquinoline-7-carboxamide Derivatives as New Selective Discoidin Domain Receptor 1 (DDR1) Inhibitors

Acute lung injury (ALI) is a deadly symptom for serious lung inflammation. Discoidin Domain Receptor 1 (DDR1) is a new potential target for anti-inflammatory drug discovery. A new selective tetrahydroisoquinoline-7-carboxamide based DDR1 inhibitor 7ae was discovered to tightly bind the DDR1 protein and potently inhibit its kinase function with a K_d value of 2.2 nM and an IC₅₀ value of 6.6 nM, respectively. The compound dose-dependently inhibited lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) release in mouse primary peritoneal macrophages (MPMs). In addition, 7ae also exhibited promising in vivo anti-inflammatory effects in a LPS-induced mouse ALI model. To the best of our knowledge, this is the first "proof of concept" investigation on the potential application of a small molecule DDR1 inhibitor to treat ALI.

Structure-Based Design of Tetrahydroisoquinoline-7-carboxamides as Selective Discoidin Domain Receptor 1 (DDR1) Inhibitors

The structure-based design of 1, 2, 3, 4-tetrahydroisoquinoline derivatives as selective DDR1 inhibitors is reported. One of the representative compounds, 6j, binds to DDR1 with a K_d value of 4.7 nM and suppresses its kinase activity with an IC₅₀ value of 9.4 nM, but it is significantly less potent for a panel of 400 nonmutated kinases. 6j also demonstrated reasonable pharmacokinetic properties and a promising oral therapeutic effect in a bleomycin-induced mouse pulmonary fibrosis model.