Synthesis and activity of new aryl- and heteroaryl-substituted 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole inhibitors of the transforming growth factor-beta type I receptor kinase domain

Transforming growth factor-β micro-environment mediated immune cell functions in cervical cancer

Propensity to develop cervical cancer (CC) in human papilloma virus (HPV) infected individual could potentially involve the impaired immune functioning. Several stages of HPV surveillance by immune cells in tumor micro-environment (TME) is regulated mainly by transforming growth factor-beta (TGF-β) and is crucial for the establishment of CC. The role of TGF-β in the initiation and progression of CC is very complex and involve different suppressor of mothers against decapentaplegic homolog (SMAD) dependent and SMAD independent signaling mechanism(s). This review summarizes the handling of HPV by immune cells such as T lymphocytes, B lymphocytes, natural killer cells (NK), dendritic cells (DC), monocytes, macrophages, myeloid derived suppressor cells (MDSC) and their regulation by TGF-β. The hijack mechanisms adapted by HPV to evade this surveillance process is discussed. Biomarkers indicating the stages of CC and immune checkpoints that can be targeted for improved outcome are included for immune-based theragnostics. This review also addresses the direct actions of TGF-β on CC cells and tumor/immune cell interactions. Therapies focused on targeting TGF-β using small molecule inhibitors, monoclonal antibodies and TGF-β chimeric antigen receptor (CAR)T cells are collated to understand the current strategies related to TGF-β in the management of CC.

Discovery of a urea-based hit compound as a novel inhibitor of transforming growth factor-β type 1 receptor: in silico and in vitro studies

Transforming growth factor β type 1 receptor (TGFβR1), a crucial serine-threonine kinase, is central to the TGFβ/Smad signaling pathway, governing cellular processes like growth, differentiation, apoptosis, and immune response. This pathway is closely linked to the epithelial-mesenchymal transition (EMT) process, which plays an important role in the metastasis of hepatocellular carcinoma (HCC). To date, only limited inhibitors targeting TGFβR1 have entered clinical trials, yet they encounter challenges, notably high toxicity, in clinical applications. Herein, an efficient virtual screening pipeline was developed. Eighty compounds were screened from a pool of over 17 million molecules based on docking scores and binding free energy. Four compounds were manually selected with the assistance of enhanced sampling method BPMD (binding pose metadynamics). The binding stability of these four compounds complexed with TGFβR1 was subsequently studied through long-timescale conventional molecular dynamics simulations. The three most promising compounds were subjected to in vitro bioactivity assays. Cpd272 demonstrated moderate inhibitory activity against TGFβR1, with an IC50 value of 1.57 ± 0.33 μM. Moreover, it exhibited cytotoxic effects on human hepatocellular carcinoma cell line Bel-7402. By shedding light on the binding mode of the receptor-ligand complexes, Cpd272 was identified as a hit compound featuring a novel urea-based scaffold capable of effectively inhibiting TGFβR1.

Advances in the discovery of activin receptor-like kinase 5 (ALK5) inhibitors

Activin receptor‑like kinase-5 (ALK5) is an outstanding member of the transforming growth factor-β (TGF-β) family. (TGF-β) signaling pathway integrates pleiotropic proteins that regulate various cellular processes such as growth, proliferation, and differentiation. Dysregulation within the signaling pathway can cause variety of diseases, such as fibrosis, cardiovascular disease, and especially cancer, rendering ALK5 a potential drug target. Hence, various small molecules have been designed and synthesized as potent ALK5 inhibitors. In this review, we shed light on the current ATP-competitive inhibitors of ALK5 through diverse heterocyclic based scaffolds that are in clinical or pre-clinical phases of development. Moreover, we focused on the binding interactions of the compounds to the ATP binding site and the structure-activity relationship (SAR) of each scaffold, revealing new scopes for designing novel candidates with enhanced selectivity and metabolic profiles.

Design, synthesis and evaluation of a pyrazolo[3,4-d]pyrimidine derivative as a novel and potent TGFβ1R1 inhibitor

The transforming growth factor β1 (TGFβ1)/SMAD signaling pathway regulates many vital physiological processes. The development of potent inhibitors targeting activin receptor-like kinase 5 (ALK5) would provide potential treatment reagents for various diseases. A significant number of ALK5 inhibitors have been discovered, and they are currently undergoing clinical evaluation at various stages. However, the clinical demands were far from being met. In this study, we utilized an alternative conformation-similarity-based virtual screening (CSVS) combined with a fragment-based drug designing (FBDD) strategy to efficiently discover a potent and active hit with a novel chemical scaffold. After structural optimization in the principle of group replacement, compound 57 was identified as the most promising ALK5 inhibitor. Compound 57 demonstrated significant inhibitory effects against the TGF-β1/SMAD signaling pathway. It could markedly attenuate the production of extracellular matrix (ECM) and deposition of collagen. Also, the lead compound showed adequate pharmacokinetic (PK) properties and good in vivo tolerance. Moreover, treatment with compound 57 in two different xerograph models showed significant inhibitory effects on the growth of pancreatic cancer cells. These results suggested that lead compound 57 refers as a promising ALK5 inhibitor both in vitro and in vivo, which merits further validation.

1,3-Disubstituted-1,2,4-triazin-6-ones with potent activity against androgen receptor-dependent prostate cancer cells

Synthesis and biological evaluation of a small, focused library of 1,3-disubstituted-1,2,4-triazin-6-ones for in vitro inhibitory activity against androgen-receptor-dependent (22Rv1) and androgen-receptor independent (PC3) castration-resistant prostate cancer (CRPC) cells led to highly active compounds with in vitro IC50 values against 22Rv1 cells of <200 nM, and with apparent selectivity for this cell type over PC3 cells. From metabolic/PK evaluations of these compounds, a 3-benzyl-1-(2,4-dichlorobenzyl) derivative had superior properties and showed considerably stronger activity, by nearly an order of magnitude, against AR-dependent LNCaP and C4-2B cells compared to AR-independent DU145 cells. This lead compound decreased AR expression in a dose and time dependent manner and displayed promising therapeutic effects in a 22Rv1 CRPC xenograft mouse model. Computational target prediction and subsequent docking studies suggested three potential known prostate cancer targets: p38a MAPK, TGF-β1, and HGFR/c-Met, with the latter case of c-Met appearing stronger, owing to close structural similarity of the lead compound to known pyridazin-3-one derivatives with potent c-Met inhibitory activity. RNA-seq analysis showed dramatic reduction of AR signalling pathway and/or target genes by the lead compound, subsequently confirmed by quantitative PCR analysis. The lead compound was highly inhibitory against HGF, the c-Met ligand, which fitted well with the computational target prediction and docking studies. These results suggest that this compound could be a promising starting point for the development of an effective therapy for the treatment of CRPC.

Ethyl ferulate suppresses post-myocardial infarction myocardial fibrosis by inhibiting transforming growth factor receptor 1

BACKGROUND

With an increasing number of myocardial infarction (MI) patients, myocardial fibrosis is becoming a widespread health concern. It's becoming more and more urgent to conduct additional research and investigations into efficient treatments. Ethyl ferulate (EF) is a naturally occurring substance with cardioprotective properties. However, the extent of its impact and the underlying mechanism of its treatment for myocardial fibrosis after MI remain unknown.

PURPOSE

The goal of this study was to look into how EF affected the signaling of the TGF-receptor 1 (TGFBR1) in myocardial fibrosis after MI.

METHODS

Echocardiography, hematoxylin-eosin (HE) and Masson trichrome staining were employed to assess the impact of EF on heart structure and function in MI-affected mice in vivo. Cell proliferation assay (MTS), 5-Ethynyl-2'-deoxyuridine (EdU), and western blot techniques were employed to examine the influence of EF on native cardiac fibroblast (CFs) proliferation and collagen deposition. Molecular simulation and surface plasmon resonance imaging (SPRi) were utilized to explore TGFBR1 and EF interaction. Cardiac-specific Tgfbr1 knockout mice (Tgfbr1ΔMCK) were utilized to testify to the impact of EF.

RESULTS

In vivo experiments revealed that EF alleviated myocardial fibrosis, improved cardiac dysfunction after MI and downregulated the TGFBR1 signaling in a dose-dependent manner. Moreover, in vitro experiments revealed that EF significantly inhibited CFs proliferation, collagen deposition and TGFBR1 signaling followed by TGF-β1 stimulation. More specifically, molecular simulation, molecular dynamics, and SPRi collectively showed that EF directly targeted TGFBR1. Lastly, knocking down of Tgfbr1 partially reversed the inhibitory activity of EF on myocardial fibrosis in MI mice.

CONCLUSION

EF attenuated myocardial fibrosis post-MI by directly suppressing TGFBR1 and its downstream signaling pathway.

Pharmacophore mapping approach to find anti-cancer phytochemicals with metformin-like activities against transforming growth factor (TGF)-beta receptor I kinase: An in silico study

The most frequently prescribed first-line treatment for type II diabetes mellitus is metformin. Recent reports asserted that this diabetes medication can also shield users from cancer. Metformin induces cell cycle arrest in cancer cells. However, the exact mechanism by which this occurs in the cancer system is yet to be elucidated. Here, we investigated the impact of metformin on cell cycle arrest in cancer cells utilizing transforming growth factor (TGF)-beta pathway. TGF-ß pathway has significant effect on cell progression and growth. In order to gain an insight on the underlying molecular mechanism of metformin's effect on TGF beta receptor 1 kinase, molecular docking was performed. Metformin was predicted to interact with transforming growth factor (TGF)-beta receptor I kinase based on molecular docking and molecular dynamics simulations. Furthermore, pharmacophore was generated for metformin-TGF-ßR1 complex to hunt for novel compounds having similar pharmacophore as metformin with enhanced anti-cancer potentials. Virtual screening with 29,000 natural compounds from NPASS database was conducted separately for the generated pharmacophores in Ligandscout® software. Pharmacophore mapping showed 60 lead compounds for metformin-TGF-ßR1 complex. Molecular docking, molecular dynamics simulation for 100 ns and ADMET analysis were performed on these compounds. Compounds with CID 72473, 10316977 and 45140078 showed promising binding affinities and formed stable complexes during dynamics simulation with aforementioned protein and thus have potentiality to be developed into anti-cancer medicaments.

Synthesis and biological evaluation of N-(3-fluorobenzyl)-4-(1-(methyl-d3)-1H-indazol-5-yl)-5-(6-methylpyridin-2-yl)-1H-imidazol-2-amine as a novel, potent ALK5 receptor inhibitor

Specific inhibition of ALK5 provides a novel method for controlling the development of cancers and fibrotic diseases. In this work, a novel series of N-(3-fluorobenzyl)-4-(1-(methyl-d₃)-1H-indazol-5-yl)-5-(6-methylpyridin-2-yl)-1H-imidazol-2-amine (11), a potential clinical candidate, was synthesized by strategic incorporation of deuterium at potential metabolic soft spots and identified as ALK5 inhibitors. This compound has a low potential for CYP-mediated drug-drug interactions as a CYP450 inhibitor (IC₅₀ = >10 μM) and showed potent inhibitory effects in cellular assay (IC₅₀ = 3.5 ± 0.4 nM). The pharmacokinetic evaluation of 11 in mice demonstrated moderate clearance (29.0 mL/min/kg) and also revealed high oral bioavailability in mice (F = 67.6%).

Heterocycles in Breast Cancer Treatment: The Use of Pyrazole Derivatives

Among the aromatic heterocycle rings, pyrazole -a five-membered ring with two adjacent nitrogen atoms in its structure has been postulated as a potent candidate in the pharmacological context. This moiety is an interesting therapeutic target covering a broad spectrum of biological activities due to its presence in many natural substances. Hence, the potential of the pyrazole derivatives as antitumor agents has been explored in many investigations, showing promising results in some cases. In this sense, breast cancer, which is already the leading cause of cancer mortality in women in some countries, has been the topic selected for this review, which covers a range of different research from the earliest studies published in 2003 to the most recent ones in 2021.

Conventional and microwave-assisted synthesis, anticancer evaluation, 99mTc-coupling and In-vivo study of some novel pyrazolone derivatives

New pyrazolone derivatives were successfully synthesized by both microwave-assisted and conventional techniques. Compound 3 (3-(3-Methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)-3-oxopropanehydrazide) displayed remarkable anti-cancer activity (IC₅₀ obtained at 8.71 and 10.63 µM for HCT-116 and MCF-7, respectively. Moreover, biodistribution study using radiolabeling approach revealed a remarked uptake of [^99mTc]Tc-compound 3 complex into tumour induced in mice. The biodistribution showed high accumulation in tumour tissues with T/NT of 6.92 after 60 min post injection. As a result of these promising data, the newly synthesized compounds especially compound 3 affords a potential radio-carrier that could be used as a tumour marker and can be used for cancer therapy after further preclinical studies.

The phytochemical plumbagin reciprocally modulates osteoblasts and osteoclasts

Bone metabolism is essential for maintaining bone mineral density and bone strength through a balance between bone formation and bone resorption. Bone formation is associated with osteoblast activity whereas bone resorption is linked to osteoclast differentiation. Osteoblast progenitors give rise to the formation of mature osteoblasts whereas monocytes are the precursors for multi-nucleated osteoclasts. Chronic inflammation, auto-inflammation, hormonal changes or adiposity have the potential to disturb the balance between bone formation and bone loss. Several plant-derived components are described to modulate bone metabolism and alleviate osteoporosis by enhancing bone formation and inhibiting bone resorption. The plant-derived naphthoquinone plumbagin is a bioactive compound that can be isolated from the roots of the Plumbago genus. It has been used as traditional medicine for treating infectious diseases, rheumatoid arthritis and dermatological diseases. Reportedly, plumbagin exerts its biological activities primarily through induction of reactive oxygen species and triggers osteoblast-mediated bone formation. It is plausible that plumbagin's reciprocal actions - inhibiting or inducing death in osteoclasts but promoting survival or growth of osteoblasts - are a function of the synergy with bone-metabolizing hormones calcitonin, Parathormone and vitamin D. Herein, we develop a framework for plausible molecular modus operandi of plumbagin in bone metabolism.

Discovery of 4-aminoquinolines as highly selective TGFβR1 inhibitors with an attenuated MAP4K4 profile for potential applications in immuno-oncology

The tumor microenvironment contains high concentrations of TGFβ, a crucial immunosuppressive cytokine. TGFβ stimulates immune escape by promoting peripheral immune tolerance to avoid tumoricidal attack. Small-molecule inhibitors of TGFβR1 are a prospective method for next-generation immunotherapies. In the present study, we identified selective 4-aminoquinoline-based inhibitors of TGFβR1 through structural and rational-based design strategies. This led to the identification of compound 4i, which was found to be selective for TGFβR1 with the exception of MAP4K4 in the kinase profiling assay. The compound was then further optimized to remove MAP4K4 activity, since MAP4K4 is vital for proper T-cell function and its inhibition could exacerbate tumor immunosuppression. Optimization efforts led to compound 4s that inhibited TGFβR1 at an IC₅₀ of 0.79 ± 0.19 nM with 2000-fold selectivity against MAP4K4. Compound 4s represents a highly selective TGFβR1 inhibitor that has potential applications in immuno-oncology.

TGF-β-induced fibrosis: A review on the underlying mechanism and potential therapeutic strategies

Transforming growth factor-beta (TGF-β) plays multiple homeostatic roles in the regulation of inflammation, proliferation, differentiation and would healing of various tissues. Many studies have demonstrated that TGF-β stimulates activation and proliferation of fibroblasts, which result in extracellular matrix deposition. Its increased expression can result in many fibrotic diseases, and the level of expression is often correlated with disease severity. On this basis, inhibition of TGF-β and its activity has great therapeutic potential for the treatment of various fibrotic diseases such as pulmonary fibrosis, renal fibrosis, systemic sclerosis and etc. By understanding the molecular mechanism of TGF-β signaling and activity, researchers were able to develop different strategies in order to modulate the activity of TGF-β. Antisense oligonucleotide was developed to target the mRNA of TGF-β to inhibit its expression. There are also neutralizing monoclonal antibodies that can target the TGF-β ligands or αvβ6 integrin to prevent binding to receptor or activation of latent TGF-β respectively. Soluble TGF-β receptors act as ligand traps that competitively bind to the TGF-β ligands. Many small molecule inhibitors have been developed to inhibit the TGF-β receptor at its cytoplasmic domain and also intracellular signaling molecules. Peptide aptamer technology has been used to target downstream TGF-β signaling. Here, we summarize the underlying mechanism of TGF-β-induced fibrosis and also review various strategies of inhibiting TGF-β in both preclinical and clinical studies.

Cordifolioside: potent inhibitor against Mpro of SARS-CoV-2 and immunomodulatory through human TGF-β and TNF-α

Therapeutic options for SARS-CoV-2 are limited merely to the symptoms or repurposed drugs and non-specific interventions to promote the human immune system. In the present study, chromatographic and in silico approaches were implemented to identify bioactive compounds which might play pivotal role as inhibitor for SARS-CoV-2 and human immunomodulator (TGF-β and TNF-α). Tinospora cordifolia (Willd.) Miers was evaluated for phenolic composition and explored for bioactive compounds by high-performance thin layer chromatography (HPTLC). Furthermore, the bioactive compounds such as cordifolioside, berberine, and magnoflorine were appraised as human immunomodulatory and potent inhibitor against Main Protease (M^pro) of SARS-CoV-2 through multiple docking strategies. Cordifolioside formed six stable H-bonds with His41, Ser144, Cys145, His163, His164, and Glu166 of M^pro of SARS-CoV-2, which displayed a significant role in the viral replication/transcription during infection acting towards the common conserved binding cleft among all strains of coronavirus. Overall, the study emphasized that the proposed cordifolioside might use for future investigations, which hold as a promising scaffold for developing anti-COVID-19 drug and reduce human cytokine storm.

Synthesis, Molecular Docking and Preliminary Antileukemic Activity of 4-Methoxybenzyl Derivatives Bearing Imidazo[2,1-b][1,3,4]thiadiazole

In this study, we synthesized 22 compounds in a series with various substitution on imidazo[2,1-b][1,3,4]thiadiazole. The potential cytotoxic activity of these compounds investigated in leukemia cell lines by Differential Nuclear Staining (DNS). Our results identified two compounds, 2-(4-methoxybenzyl)-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl thiocyanate and 6-(4-chlorophenyl)-2-(4-methoxybenzyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde, exhibited the most cytotoxic effect against murine leukemia cells (L1210), human T-lymphocyte cells (CEM) and human cervix carcinoma cells (HeLa) with IC50 values ranging between 0.79 and 1.6 μM. The results indicate that 2-(4-methoxybenzyl)-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl thiocyanate is inducing phosphatidylserine externalization and caspase-3 activation which are both a hallmark of apoptosis. Docking studies showed that 2-(4-methoxybenzyl)-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl thiocyanate binds within the active sites of transforming growth factor beta (TGF-β) type I receptor kinase domain by strong hydrogen binding and hydrophobic interactions.

TGFβ-Directed Therapeutics: 2020

The transforming growth factor-beta (TGFβ) pathway is essential during embryo development and in maintaining normal homeostasis. During malignancy, the TGFβ pathway is co-opted by the tumor to increase fibrotic stroma, to promote epithelial to mesenchymal transition increasing metastasis and producing an immune-suppressed microenvironment which protects the tumor from recognition by the immune system. Compelling preclinical data demonstrate the therapeutic potential of blocking TGFβ function in cancer. However, the TGFβ pathway cannot be described as a driver of malignant disease. Two small molecule kinase inhibitors which block the serine-threonine kinase activity of TGFβRI on TGFβRII, a pan-TGFβ neutralizing antibody, a TGFβ trap, a TGFβ antisense agent, an antibody which stabilizes the latent complex of TGFβ and a fusion protein which neutralizes TGFβ and binds PD-L1 are in clinical development. The challenge is how to most effectively incorporate blocking TGFβ activity alone and in combination with other therapeutics to improve treatment outcome.

Docking-based virtual screening of TβR1 inhibitors: evaluation of pose prediction and scoring functions

To improve the reliability of virtual screening for transforming growth factor-beta type 1 receptor (TβR1) inhibitors, 2 docking methods and 11 scoring functions in Discovery Studio software were evaluated and validated in this study. LibDock and CDOCKER protocols were performed on a test set of 24 TβR1 protein-ligand complexes. Based on the root-mean-square deviation (RMSD) values (in Å) between the docking poses and co-crystal conformations, the CDOCKER protocol can be efficiently applied to obtain more accurate dockings in medium-size virtual screening experiments of TβR1, with a successful docking rate of 95%. A dataset including 281 known active and 8677 inactive ligands was used to determine the best scoring function. The receiver operating characteristic (ROC) curves were used to compare the performance of scoring functions in attributing best scores to active than inactive ligands. The results show that Ludi 1, PMF, Ludi 2, Ludi 3, PMF04, PLP1, PLP2, LigScore2, Jain and LigScore1 are better scoring functions than the random distribution model, with AUC of 0.864, 0.856, 0.842, 0.812, 0.776, 0.774, 0.769, 0.762, 0.697 and 0.660, respectively. Based on the pairwise comparison of ROC curves, Ludi 1 and PMF were chosen as the best scoring functions for virtual screening of TβR1 inhibitors. Further enrichment factors (EF) analysis also supports PMF and Ludi 1 as the top two scoring functions.

An Overview of Privileged Scaffold: Quinolines and Isoquinolines in Medicinal Chemistry as Anticancer Agents

Cancer is one of the most difficult diseases and causes of death for many decades. Many pieces of research are continuously going on to get a solution for cancer. Quinoline and isoquinoline derivatives have shown their possibilities to work as an antitumor agent in anticancer treatment. The members of this privileged scaffold quinoline and isoquinoline have shown their controlling impacts on cancer treatment through various modes. In particular, this review suggests the current scenario of quinoline and isoquinoline derivatives as antitumor agents and refine the path of these derivatives to find and develop new drugs against an evil known as cancer.

Synthesis and biological evaluation of 4-(pyridin-4-oxy)-3-(3,3-difluorocyclobutyl)-pyrazole derivatives as novel potent transforming growth factor-β type 1 receptor inhibitors

Inhibition of transforming growth factor β (TGF-β) type 1 receptor (ALK5) provides a feasible approach for the treatment of fibrotic diseases and malignant tumors. In this study, we designed and synthesized a new series of 4-(pyridin-4-oxy)-3-(3,3-difluorocyclobutyl)-pyrazole derivatives, and evaluated biologically as TGF-β type 1 receptor inhibitors. The most potent compound 15r inhibited the ALK5 enzyme and NIH3T3 cell viability with IC₅₀ values of 44 and 42.5 nM, respectively. Compound 15r also displayed better oral plasma exposure and excellent bioavailability than LY-3200882, and in vivo inhibited 65.7% of the tumor growth in a CT26 xenograft mouse model.

Small Molecular Immune Modulators as Anticancer Agents

After decades of intense effort, immune checkpoint inhibitors have been conclusively demonstrated to be effective in cancer treatments and thus are revolutionizing the concepts in the treatment of cancers. Immuno-oncology has arrived and will play a key role in cancer treatment in the foreseeable future. However, efforts to find novel methods to improve the immune response to cancer have not ceased. Small-molecule approaches offer inherent advantages over biologic immunotherapies since they can cross cell membranes, penetrate into tumor tissue and tumor microenvironment more easily, and are amenable to be finely controlled than biological agents, which may help reduce immune-related adverse events seen with biologic therapies and provide more flexibility for the combination use with other therapies and superior clinical benefit. On the one hand, small-molecule therapies can modulate the immune response to cancer by restoring the antitumor immunity, promoting more effective cytotoxic lymphocyte responses, and regulating tumor microenvironment, either directly or epigenetically. On the other hand, the combination of different mechanisms of small molecules with antibodies and other biologics demonstrated admirable synergistic effect in clinical settings for cancer treatment and may expand antibodies' usefulness for broader clinical applications. This chapter provides an overview of small-molecule immunotherapeutic approaches either as monotherapy or in combination for the treatment of cancer.

Synthesis, biological evaluation and molecular modelling of 2,4-disubstituted-5-(6-alkylpyridin-2-yl)-1H-imidazoles as ALK5 inhibitors

A series of 2,4-disubstituted-5-(6-alkylpyridin-2-yl)-1H-imidazoles, 7a–c, 11a–h, and 16a–h has been synthesised and evaluated for their ALK5 inhibitory activity in an enzyme assay and in a cell-based luciferase reporter assay. Incorporation of a quinoxalin-6-yl moiety and a methylene linker at the 4- and 2-position of the imidazole ring, respectively, and a m-CONH₂ substituent in the phenyl ring generated a highly potent and selective ALK5 inhibitor 11e. Docking model of ALK5 in complex with 11e showed that it fitted well in the ATP-binding pocket with favourable interactions.

Cascade and multicomponent synthesis of structurally diverse 2-(pyrazol-3-yl)pyridines and polysubstituted pyrazoles

The cascade reaction between N-tosylhydrazones and 2-alkynylpyridines leads to 2-(pyrazol-3-yl)pyridines, important structural motifs in ligands for transition metals and bioactive molecules. When the reaction is conducted with 2,6-diethynylpyridine, the important 2,6-bis(pyrazolyl)pyridines are obtained, featuring the arrangement of tridentate and also pentadentate ligands. A novel three-component version of the reaction has been designed, which involves the use of α-bromo-N-tosylhydrazones, alkynylpyridines and NH-azoles. The generality of the multicomponent reaction is further illustrated by the preparation of different polysubstituted pyrazoles by employing an array of terminal alkynes. In these multicomponent reactions, complex molecules featuring three different heterocycles are assembled in a single step from commercial materials, enabling the fast generation of molecular diversity.

Development of small molecule inhibitors targeting TGF-β ligand and receptor: Structures, mechanism, preclinical studies and clinical usage

Transforming growth factor-β (TGF-β) is a member of a superfamily of pleiotropic proteins that regulate multiple cellular processes such as growth, development and differentiation. Following binding to type I and II TGF-β serine/threonine kinase receptors, TGF-β activates downstream signaling cascades involving both SMAD-dependent and -independent pathways. Aberrant TGF-β signaling is associated with a variety of diseases, such as fibrosis, cardiovascular disease and cancer. Hence, the TGF-β signaling pathway is recognized as a potential drug target. Various organic molecules have been designed and developed as TGF-β signaling pathway inhibitors and they function by either down-regulating the expression of TGF-β or by inhibiting the kinase activities of the TGF-β receptors. In this review, we discuss the current status of research regarding organic molecules as TGF-β inhibitors, focusing on the biological functions and the binding poses of compounds that are in the market or in the clinical or pre-clinical phases of development.

Structure-Based Virtual Screening, Molecular Dynamics and Binding Free Energy Calculations of Hit Candidates as ALK-5 Inhibitors

Activin-like kinase 5 (ALK-5) is involved in the physiopathology of several conditions, such as pancreatic carcinoma, cervical cancer and liver hepatoma. Cellular events that are landmarks of tumorigenesis, such as loss of cell polarity and acquisition of motile properties and mesenchymal phenotype, are associated to deregulated ALK-5 signaling. ALK-5 inhibitors, such as SB505154, GW6604, SD208, and LY2157299, have recently been reported to inhibit ALK-5 autophosphorylation and induce the transcription of matrix genes. Due to their ability to impair cell migration, invasion and metastasis, ALK-5 inhibitors have been explored as worthwhile hits as anticancer agents. This work reports the development of a structure-based virtual screening (SBVS) protocol aimed to prospect promising hits for further studies as novel ALK-5 inhibitors. From a lead-like subset of purchasable compounds, five molecules were identified as putative ALK-5 inhibitors. In addition, molecular dynamics and binding free energy calculations combined with pharmacokinetics and toxicity profiling demonstrated the suitability of these compounds to be further investigated as novel ALK-5 inhibitors.

Recent Advances in Understanding Mechanisms of TGF Beta Signaling and Its Role in Glioma Pathogenesis

Transforming growth factor beta (TGF-β) signaling is involved in the regulation of proliferation, differentiation and survival/or apoptosis of many cells, including glioma cells. TGF-β acts via specific receptors activating multiple intracellular pathways resulting in phosphorylation of receptor-regulated Smad2/3 proteins that associate with the common mediator, Smad4. Such complex translocates to the nucleus, binds to DNA and regulates transcription of many genes. Furthermore, TGF-β-activated kinase-1 (TAK1) is a component of TGF-β signaling and activates mitogen-activated protein kinase (MAPK) cascades. Negative regulation of TGF-β/Smad signaling may occur through the inhibitory Smad6/7. While genetic alterations in genes related to TGF-β signaling are relatively rare in gliomas, the altered expression of those genes is a frequent event. The increased expression of TGF-β1-3 correlates with a degree of malignancy of human gliomas. TGF-β may contribute to tumor pathogenesis in many ways: by direct support of tumor growth, by maintaining self-renewal of glioma initiating stem cells and inhibiting anti-tumor immunity. Glioma initiating cells are dedifferentiated cells that retain many stem cell-like properties, play a role in tumor initiation and contribute to its recurrence. TGF-β1,2 stimulate expression of the vascular endothelial growth factor as well as the plasminogen activator inhibitor and some metalloproteinases that are involved in vascular remodeling, angiogenesis and degradation of the extracellular matrix. Inhibitors of TGF-β signaling reduce viability and invasion of gliomas in animal models and show a great promise as novel, potential anti-tumor therapeutics.

A Perspective on the Development of TGF-β Inhibitors for Cancer Treatment

Transforming growth factor (TGF)-β is a secreted multifunctional cytokine that signals via plasma membrane TGF-β type I and type II receptors and intercellular SMAD transcriptional effectors. Aberrant inter- and intracellular TGF-β signaling can contribute to cancer progression. In normal cells and early stages of cancer, TGF-β can stimulate epithelial growth arrest and elicit a tumor suppressor function. However, in late stages of cancer, when the cytostatic effects of TGF-β in cancer cells are blocked, TGF-β signaling can act as tumor promoter by its ability to stimulate epithelial-to-mesenchymal transition of cancer cells, by stimulating angiogenesis, and by promoting evasion of immune responses. In this review, we will discuss the rationale and challenges of targeting TGF-β signaling in cancer and summarize the clinical status of TGF-β signaling inhibitors that interfere with TGFβ bioavailability, TGF-βreceptor interaction, or TGF-β receptor kinase function. Moreover, we will discuss targeting of TGF-β signaling modulators and downstream effectors as well as alternative approaches by using promising technologies that may lead to entirely new classes of drugs.

A Perspective on the Development of TGF-β Inhibitors for Cancer Treatment

Transforming growth factor (TGF)-β is a secreted multifunctional cytokine that signals via plasma membrane TGF-β type I and type II receptors and intercellular SMAD transcriptional effectors. Aberrant inter- and intracellular TGF-β signaling can contribute to cancer progression. In normal cells and early stages of cancer, TGF-β can stimulate epithelial growth arrest and elicit a tumor suppressor function. However, in late stages of cancer, when the cytostatic effects of TGF-β in cancer cells are blocked, TGF-β signaling can act as tumor promoter by its ability to stimulate epithelial-to-mesenchymal transition of cancer cells, by stimulating angiogenesis, and by promoting evasion of immune responses. In this review, we will discuss the rationale and challenges of targeting TGF-β signaling in cancer and summarize the clinical status of TGF-β signaling inhibitors that interfere with TGF−β bioavailability, TGF-β/receptor interaction, or TGF-β receptor kinase function. Moreover, we will discuss targeting of TGF-β signaling modulators and downstream effectors as well as alternative approaches by using promising technologies that may lead to entirely new classes of drugs.

Structural biology of the TGFβ family

The transforming growth factor beta (TGFβ) signaling pathway orchestrates a wide breadth of biological processes, ranging from bone development to reproduction. Given this, there has been a surge of interest from the drug development industry to modulate the pathway – at several points. This review discusses and provides additional context for several layers of the TGFβ signaling pathway from a structural biology viewpoint. The combination of structural techniques coupled with biophysical studies has provided a foundational knowledge of the molecular mechanisms governing this high impact, ubiquitous pathway, underlying many of the current therapeutic pursuits. This work seeks to consolidate TGFβ-related structural knowledge and educate other researchers of the apparent gaps that still prove elusive. We aim to highlight the importance of these structures and provide the contextual information to understand the contribution to the field, with the hope of advancing the discussion and exploration of the TGFβ signaling pathway.

Impact statement

The transforming growth factor beta (TGFβ) signaling pathway is a multifacetted and highly regulated pathway, forming the underpinnings of a large range of biological processes. Here, we review and consolidate the key steps in TGFβ signaling using literature rooted in structural and biophysical techniques, with a focus on molecular mechanisms and gaps in knowledge. From extracellular regulation to ligand–receptor interactions and intracellular activation cascades, we hope to provide an introductory base for understanding the TGFβ pathway as a whole.

Novel transforming growth factor beta receptor I kinase inhibitor galunisertib (LY2157299) in advanced hepatocellular carcinoma

BACKGROUND AND AIMS

We assessed the activity of galunisertib, a small molecule inhibitor of the transforming growth factor beta (TGF-β1) receptor I, in second-line patients with hepatocellular carcinoma (HCC) in two cohorts of baseline serum alpha fetoprotein (AFP).

METHODS

Patients with advanced HCC who progressed on or were ineligible to receive sorafenib, Child-Pugh A/B7 and ECOG PS ≤1 were enrolled into Part A (AFP ≥ 1.5× ULN) or Part B (AFP < 1.5× ULN). Patients were treated with 80 or 150 mg galunisertib BID for 14 days per 28-day cycle. Endpoints were time-to-progression (TTP) and changes in circulating AFP and TGF-β1 levels, as well as safety, pharmacokinetics, progression-free survival and overall survival (OS).

RESULTS

Patients (n = 149) were enrolled with median age 65 years. Median TTP was 2.7 months (95% CI: 1.5-2.9) in Part A (n = 109) and 4.2 months (95% CI: 1.7-5.5) in Part B (n = 40). Median OS was 7.3 months (95% CI: 4.9-10.5) in Part A and 16.8 months (95% CI: 10.5-24.4) in Part B. OS was longer in AFP responders (>20% decrease from baseline, Part A) compared to non-responders (21.5 months vs 6.8 months). OS was longer in TGF-β1 responders (>20% decrease from baseline, all patients) compared to non-responders. The most common Grade 3/4 treatment-related adverse events were neutropenia (n = 4) and fatigue, anaemia, increased bilirubin, hypoalbuminemia and embolism (each, n = 2).

CONCLUSIONS

Galunisertib treatment had a manageable safety profile in patients with HCC. Lower baseline AFP and a response in AFP or TGF-β1 levels (vs no response) correlated with longer survival.

TRIAL REGISTRATION NUMBER

NCT01246986 at ClinicalTrials.gov.

Development of novel therapeutics for glaucoma filtration surgery based on transforming growth factor-β receptor 1 inhibition

QSAR modeling with computer-aided drug design was used for the in silico development of novel therapeutics for glaucoma filtration surgery.

Luteolin Inhibits Vascular Smooth Muscle Cell Proliferation and Migration by Inhibiting TGFBR1 Signaling

Vascular smooth muscle cell (VSMC) proliferation and migration play a critical role in the development of arterial remodeling during various vascular diseases including atherosclerosis, hypertension, and related diseases. Luteolin is a food-derived flavonoid that exerts protective effects on cardiovascular diseases. Here, we investigated whether transforming growth factor-β receptor 1 (TGFBR1) signaling underlies the inhibitory effects of luteolin on VSMC proliferation and migration. We found that luteolin reduced the proliferation and migration of VSMCs, specifically A7r5 and HASMC cells, in a dose-dependent manner, based on MTS and EdU, and Transwell and wound healing assays, respectively. We also demonstrated that it inhibited the expression of proliferation-related proteins including PCNA and Cyclin D1, as well as the migration-related proteins MMP2 and MMP9, in a dose-dependent manner by western blotting. In addition, luteolin dose-dependently inhibited the phosphorylation of TGFBR1, Smad2, and Smad3. Notably, adenovirus-mediated overexpression of TGFBR1 enhanced TGFBR1, Smad2, and Smad3 activation in VSMCs and partially blocked the inhibitory effect of luteolin on TGFBR1, Smad2, and Smad3. Moreover, overexpression of TGFBR1 rescued the inhibitory effects of luteolin on the proliferation and migration of VSMCs. Additionally, molecular docking showed that this compound could dock onto an agonist binding site of TGFBR1, and that the binding energy between luteolin and TGFBR1 was -10.194 kcal/mol. Simulations of molecular dynamics showed that TGFBR1-luteolin binding was stable. Collectively, these data demonstrated that luteolin might inhibit VSMC proliferation and migration by suppressing TGFBR1 signaling.

Activation of renal profibrotic TGFβ controlled signaling cascades by calcineurin and mTOR inhibitors

The calcineurin inhibitors (CNI) cyclosporine A (CsA) and tacrolimus represent potent immunosuppressive agents frequently used for solid organ transplantation and treatment of autoimmune disorders. Despite of their immense therapeutic benefits, residual fibrosis mainly in the kidney represents a common side effect of long-term therapy with CNI. Regardless of the immunosuppressive action, an increasing body of evidence implicates that a drug-induced increase in TGFβ and subsequent activation of TGFβ-initiated signaling pathways is closely associated with the development and progression of CNI-induced nephropathy. Mechanistically, an increase in reactive oxygen species (ROS) generation due to drug-induced changes in the intracellular redox homeostasis functions as an important trigger of the profibrotic signaling cascades activated under therapy with CNI. Although, inhibitors of the mechanistic target of rapamycin (mTOR) kinase have firmly been established as alternative compounds with a lower nephrotoxic potential, an activation of fibrogenic signaling cascades has been reported for these drugs as well. This review will comprehensively summarize recent advances in the understanding of profibrotic signaling events modulated by these widely used compounds with a specific focus put on mechanisms occurring independent of their respective immunosuppressive action. Herein, the impact of redox modulation, the activation of canonical TGFβ and non-Smad pathways and modulation of autophagy by both classes of immunosuppressive drugs will be highlighted and discussed in a broader perspective. The comprehensive knowledge of profibrotic signaling events specifically accompanying the immunomodulatory activity of these widely used drugs is needed for a reliable benefit-risk assessment under therapeutic regimens.

Interactions between the circadian clock and TGF-β signaling pathway in zebrafish

Background

TGF-β signaling is a cellular pathway that functions in most cells and has been shown to play a role in multiple processes, such as the immune response, cell differentiation and proliferation. Recent evidence suggests a possible interaction between TGF-β signaling and the molecular circadian oscillator. The current study aims to characterize this interaction in the zebrafish at the molecular and behavioral levels, taking advantage of the early development of a functional circadian clock and the availability of light-entrainable clock-containing cell lines.

Results

Smad3a, a TGF-β signaling-related gene, exhibited a circadian expression pattern throughout the brain of zebrafish larvae. Both pharmacological inhibition and indirect activation of TGF-β signaling in zebrafish Pac-2 cells caused a concentration dependent disruption of rhythmic promoter activity of the core clock gene Per1b. Inhibition of TGF-β signaling in intact zebrafish larvae caused a phase delay in the rhythmic expression of Per1b mRNA. TGF-β inhibition also reversibly disrupted, phase delayed and increased the period of circadian rhythms of locomotor activity in zebrafish larvae.

Conclusions

The current research provides evidence for an interaction between the TGF-β signaling pathway and the circadian clock system at the molecular and behavioral levels, and points to the importance of TGF-β signaling for normal circadian clock function. Future examination of this interaction should contribute to a better understanding of its underlying mechanisms and its influence on a variety of cellular processes including the cell cycle, with possible implications for cancer development and progression.

Structure, molecular dynamics simulation, and docking studies of Dictyostelium discoideum and human STRAPs

The Serine Threonine kinase Receptor Associated Protein (STRAP) is a WD40 containing protein that provides a platform for protein interactions during cell proliferation and development. Overexpression and misregulation of STRAP contributes to various carcinomas that are now recognized as therapeutic targets especially for colorectal and lung cancers. The present study was undertaken to find an effective drug against this molecule using a simple system like Dictyostelium discoideum; which shares close homology to humans. Using techniques like structural modeling, molecular dynamics (MD) simulation and molecular docking, we found similar structure and dynamic behaviors in both, except for the presence of dissimilar numbers of β-sheets and loop segments. We identified a novel and potential drug targeted to STRAP. The results obtained allow us to use Dictyostelium as a model system for further in vivo studies. Finally, the results of protein-protein interactions using molecular docking and essential dynamics studies show STRAP to participate in TGF-β signaling in humans. Further, we show some structural units that govern the interaction of TGFβ-RI with STRAP and Smad7 proteins in TGF-β signaling pathway. In conclusion, we propose that D. discoideum can be used for enhancing our knowledge about STRAP protein.

Synthesis of Dihydrooxepino[3,2-c]Pyrazoles via Claisen Rearrangement and Ring-Closing Metathesis from 4-Allyloxy-1H-pyrazoles

Synthesis of novel pyrazole-fused heterocycles, i.e., dihydro-1H- or 2H-oxepino[3,2-c]pyrazoles (6 or 7) from 4-allyloxy-1H-pyrazoles (1) via combination of Claisen rearrangement and ring-closing metathesis (RCM) has been achieved. A suitable catalyst for the RCM of 5-allyl-4-allyloxy-1H-pyrazoles (4) was proved to be the Grubbs second generation catalyst (Grubbs2nd) to give the predicted RCM product at room temperature in three hours. The same reactions of the regioisomer, 3-allyl-4-allyloxy-1H-pyrazoles (5), also proceeded to give the corresponding RCM products. On the other hand, microwave aided RCM at 140 °C on both of 4 and 5 afforded mixtures of isomeric products with double bond rearrangement from normal RCM products in spite of remarkable reduction of the reaction time to 10 min.

A novel highly potent trivalent TGF-β receptor trap inhibits early-stage tumorigenesis and tumor cell invasion in murine Pten-deficient prostate glands

The effects of transforming growth factor beta (TGF-β) signaling on prostate tumorigenesis has been shown to be strongly dependent on the stage of development, with TGF-β functioning as a tumor suppressor in early stages of disease and as a promoter in later stages. To study in further detail the paradoxical tumor-suppressive and tumor-promoting roles of the TGF-β pathway, we investigated the effect of systemic treatment with a TGF-β inhibitor on early stages of prostate tumorigenesis. To ensure effective inhibition, we developed and employed a novel trivalent TGF-β receptor trap, RER, comprised of domains derived from the TGF-β type II and type III receptors. This trap was shown to completely block TβRII binding, to antagonize TGF-β1 and TGF-β3 signaling in cultured epithelial cells at low picomolar concentrations, and it showed equal or better anti-TGF-β activities than a pan TGF-β neutralizing antibody and a TGF-β receptor I kinase inhibitor in various prostate cancer cell lines. Systemic administration of RER inhibited prostate tumor cell proliferation as indicated by reduced Ki67 positive cells and invasion potential of tumor cells in high grade prostatic intraepithelial neoplasia (PIN) lesions in the prostate glands of Pten conditional null mice. These results provide evidence that TGF-β acts as a promoter rather than a suppressor in the relatively early stages of this spontaneous prostate tumorigenesis model. Thus, inhibition of TGF-β signaling in early stages of prostate cancer may be a novel therapeutic strategy to inhibit the progression as well as the metastatic potential in patients with prostate cancer.

Molecular docking analysis of curcumin analogues against kinase domain of ALK5

During metastasis, cancer cells transcend from primary site to normal cells area upon attaining epithelial to mesenchymal transition (EMT) causing malignant cancer disease. Increased expression of TGF-β and its receptor ALK5 is an important hallmark of malignant cancer. In the present study, efficacy of curcumin and its analogues as inhibitors of ALK5 (TGFβR-I) receptor was evaluated using in silico approaches. A total of 142 curcumin analogues and curcumin were retrieved from peer reviewed literature and constructed a combinatorial library. Further their drug-likeness was assessed using Molinspiration, cheminformatics and preADMET online servers. The interaction of 142 curcumin analogues and curcumin with ALK5 receptor was studied using Autodock Vina. This study revealed six curcumin analogues as promising ALK5 inhibitors with significant binding energy and H-bonding interaction.

Galunisertib (LY2157299), a transforming growth factor-β receptor I kinase inhibitor, attenuates acute pancreatitis in rats

Galunisertib (LY2157299), a selective ATP-mimetic inhibitor of TGF-β receptor I (TGF-βRI), is the only known TGF-β pathway inhibitor. In the present study, we investigated the effect of galunisertib on taurocholate (TAC)-induced acute pancreatitis (AP) in rats, and the role of TGF-β and NF-κB signaling pathways. AP was induced by infusion of TAC into the pancreatic duct of Sprague-Dawley male rats (n=30). The rats (220±50 g) were administered galunisertib intragastrically [75 mg·kg^-1·day^-1 for 2 days (0 and 24 h)]. Serum IL-1β, IL-6, TNF-α, amylase (AMY), lipase (LIP), and myeloperoxidase (MPO) levels were measured by ELISA. NF-κB activity was detected by electrophoretic mobility shift assay (EMSA); NF-κBp65 and TGF-β1 proteins, as well as TGF-βRI and p-Smad2/3 proteins, were detected by western blot assay. Cell apoptosis was detected by TUNEL assay. H&E staining was used to evaluate the histopathological alterations of the pancreas. Galunisertib treatment attenuated the severity of AP and decreased the pancreatic histological score. In addition, number of apoptotic cells were significantly increased in the galunisertib-treated group (16.38±2.26) than in the AP group (8.14±1.27) and sham-operated group (1.82±0.73; P<0.05 and P<0.01, respectively). Galunisertib decreased the expression levels of TGF-βRI and p-Smad2/3 and inhibited NF-κB activation and p65 translocation compared with the sham-operated group. Furthermore, serum IL-1β, IL-6, TNF-α, AMY and LIP levels and tissue MPO activity were significantly decreased in the galunisertib-treated group. Our data demonstrate that galunisertib attenuates the severity of TAC-induced experimental AP in rats by inducing apoptosis in the pancreas, inhibiting the activation of TGF-β signals and NF-κB as well as the secretion of pro-inflammatory cytokines.

ALK5 kinase inhibitory activity and synthesis of 2,3,4-substituted 5,5-dimethyl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazoles

A series of 2,3,4-substituted 5,5-dimethyl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazoles (DPPs) was synthesized and evaluated for their ALK5 inhibition activity. The most potent compounds displayed submicromolar IC₅₀ values for ALK5. Preliminary profiling of one of the most active compounds in a panel of 50 protein kinases revealed its selectivity for ALK5. In cells, the compounds caused dose-dependent dephosphorylation of SMAD2, a well-established substrate of ALK5. In addition, the compounds blocked translocation of SMAD2/3 to nuclei of cells stimulated with TGFβ and the protein remained predominantly in cytoplasm, further confirming their molecular target. Therefore, novel DPP derivatives proved to be active as ALK5 inhibitors.

Loss of TRIM33 causes resistance to BET bromodomain inhibitors through MYC- and TGF-β-dependent mechanisms

Bromodomain and extraterminal domain protein inhibitors (BETi) hold great promise as a novel class of cancer therapeutics. Because acquired resistance typically limits durable responses to targeted therapies, it is important to understand mechanisms by which tumor cells adapt to BETi. Here, through pooled shRNA screening of colorectal cancer cells, we identified tripartite motif-containing protein 33 (TRIM33) as a factor promoting sensitivity to BETi. We demonstrate that loss of TRIM33 reprograms cancer cells to a more resistant state through at least two mechanisms. TRIM33 silencing attenuates down-regulation of MYC in response to BETi. Moreover, loss of TRIM33 enhances TGF-β receptor expression and signaling, and blocking TGF-β receptor activity potentiates the antiproliferative effect of BETi. These results describe a mechanism for BETi resistance and suggest that combining inhibition of TGF-β signaling with BET bromodomain inhibition may offer new therapeutic benefits.

Design, synthesis and optimization of novel Alk5 (activin-like kinase 5) inhibitors

Using SBDD, a series of 4-amino-7-azaindoles were discovered as a novel class of Alk5 inhibitors that are potent in both Alk5 enzymatic and cellular assays. Subsequently a ring cyclization strategy was utilized to improve ADME properties leading to the discovery of a series of 1H-imidazo[4,5-c]pyridin-2(3H)-one drug like Alk5 inhibitors.

Crystal structures of apo and inhibitor-bound TGFβR2 kinase domain: insights into TGFβR isoform selectivity

The cytokine TGF-β modulates a number of cellular activities and plays a critical role in development, hemostasis and physiology, as well as in diseases including cancer and fibrosis. TGF-β signals through two transmembrane serine/threonine kinase receptors: TGFβR1 and TGFβR2. Multiple structures of the TGFβR1 kinase domain are known, but the structure of TGFβR2 remains unreported. Wild-type TGFβR2 kinase domain was refractory to crystallization, leading to the design of two mutated constructs: firstly, a TGFβR1 chimeric protein with seven ATP-site residues mutated to their counterparts in TGFβR2, and secondly, a reduction of surface entropy through mutation of six charged residues on the surface of the TGFβR2 kinase domain to alanines. These yielded apo and inhibitor-bound crystals that diffracted to high resolution (<2 Å). Comparison of these structures with those of TGFβR1 reveal shared ligand contacts as well as differences in the ATP-binding sites, suggesting strategies for the design of pan and selective TGFβR inhibitors.

A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides

A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.

Regulatory T-cell depletion in the gut caused by integrin β7 deficiency exacerbates DSS colitis by evoking aberrant innate immunity

Integrin α4β7 controls lymphocyte trafficking into the gut and has essential roles in inflammatory bowel disease (IBD). The α4β7-blocking antibody vedolizumab is approved for IBD treatment; however, high dose of vedolizumab aggravates colitis in a small percentage of patients. Herein, we show that integrin β7 deficiency results in colonic regulatory T (Treg) cell depletion and exacerbates dextran sulfate sodium (DSS) colitis by evoking aberrant innate immunity. In DSS-treated β7-deficient mice, the loss of colonic Treg cells induces excessive macrophage infiltration in the colon via upregulation of colonic epithelial intercellular adhesion molecule 1 and increases proinflammatory cytokine expression, thereby exacerbating DSS-induced colitis. Moreover, reconstitution of the colonic Treg cell population in β7-deficient mice suppresses aberrant innate immune response in the colon and attenuates DSS colitis. Thus, integrin α4β7 is essential for suppression of DSS colitis as it regulates the colonic Treg cell population and innate immunity.