Multiple Signal Transduction Pathways Research Articles

Final results of a first-in-human phase I dose escalation trial of daily oral zelenirstat, a n-myristoyltransferase inhibitor, in patients with advanced solid tumors and relapsed/refractory B-cell lymphomas.

3082 Background: Myristoylation, the N-terminal modification of proteins with the fatty acid myristate, regulates multiple membrane-bound signal transduction pathways important in cancer cell biology, including Src and Src family of protein tyrosine kinases. This modification is catalyzed by two N-myristoyltransferases (NMT), NMT1 and NMT2. Zelenirstat is a first-in-class oral small molecule NMT inhibitor with strong affinity for both NMT1 and NMT2 proteins. Transcriptomic analysis of zelenirstat treated cell lines identified a myristoylation inhibition sensitivity signature in cancer cells most likely to respond to NMT inhibitor therapy; high sensitivity scores were seen in a range of solid cancers and diffuse large B-cell lymphoma. Based on tumor regression and safety in preclinical models, we hypothesized zelenirstat would be safe to administer and show anticancer activity. Methods: Patients (pts) with advanced solid tumors and relapsed/refractory (R/R) B-cell lymphomas were enrolled in a multicenter, open label, phase I dose escalation trial of oral daily zelenirstat, administered in 28-day cycles until disease progression or unacceptable toxicity (NCT04836195). The primary endpoints were to evaluate dose-limiting toxicities (DLT) to establish a maximum tolerated dose (MTD). Secondary endpoints were to characterize the pharmacokinetic parameters of zelenirstat and assess anticancer activity. Results: Twenty-nine pts (17 females; 12 males; median age 65 years; median prior systemic treatments 4; 25 advanced solid tumor; 4 R/R B-cell lymphoma) were enrolled and 24 pts were DLT-evaluable. Dose cohorts ranged from 20 mg once daily (OD) to 280 mg OD without DLT until the 280 mg cohort where three DLTs were observed: Gr 3 diarrhea, Gr 3 diverticulitis, and Gr 3 dehydration. MTD and recommended phase 2 dose was established at 210 mg OD. Common adverse events were Gr ≤ 2 nausea, vomiting, diarrhea, and fatigue. Plasma concentrations peaked between 1 and 4 hours across the cohorts with terminal half-lives ranging from 6.7 to 12 hours. Steady state was achieved by Day 8 to 15, and in the higher dose cohorts, trough concentrations exceeded the levels predicted to be therapeutic. Stable disease as best response was seen in 8 (28%) heavily pre-treated pts (3 colorectal, 2 ovarian, 1 pancreatic, 1 appendiceal, and 1 bladder). Progression-free survival, overall survival, and weighted health status were significantly better in pts receiving 210 mg OD compared to those receiving lower doses. Conclusions: Zelenirstat is well-tolerated, reaches plasma concentrations highly active in preclinical models, and shows preliminary signs of encouraging anticancer activity. NMT inhibition represents a new target for ongoing research efforts and further clinical development of zelenirstat is warranted. Clinical trial information: NCT04836195 .

Framework for exploring the sensory repertoire of the human gut microbiota.

Bacteria sense changes in their environment and transduce signals to adjust their cellular functions accordingly. For this purpose, bacteria employ various sensors feeding into multiple signal transduction pathways. Signal recognition by bacterial sensors is studied mainly in a few model organisms, but advances in genome sequencing and analysis offer new ways of exploring the sensory repertoire of many understudied organisms. The human gut is a natural target of this line of study: it is a nutrient-rich and dynamic environment and is home to thousands of bacterial species whose activities impact human health. Many gut commensals are also poorly studied compared to model organisms and are mainly known through their genome sequences. To begin exploring the signals human gut commensals sense and respond to, we have designed a framework that enables the identification of sensory domains, prediction of signals that they recognize, and experimental verification of these predictions. We validate this framework's functionality by systematically identifying amino acid sensors in selected bacterial genomes and metagenomes, characterizing their amino acid binding properties, and demonstrating their signal transduction potential.IMPORTANCESignal transduction is a central process governing how bacteria sense and respond to their environment. The human gut is a complex environment with many living organisms and fluctuating streams of nutrients. One gut inhabitant, Escherichia coli, is a model organism for studying signal transduction. However, E. coli is not representative of most gut microbes, and signaling pathways in the thousands of other organisms comprising the human gut microbiota remain poorly understood. This work provides a foundation for how to explore signals recognized by these organisms.

P22 A single-cell map of the epigenomic landscape in keratinocytes exposed to the cytokine milieu of atopic dermatitis

Abstract Introduction and aims In atopic dermatitis (AD), induction of inflammatory responses regulated by cytokines such as of thymic stromal lymphopoietin exacerbate the disrupted integrity of the skin barrier. Cytokines, such as interleukin (IL)-4, IL-13 and IL-22, present in the skin milieu, bind to their corresponding receptors on the cell surface of keratinocytes, activating multiple signal transduction pathways that lead to changes in the gene expression profile of keratinocytes, in part, by modulating chromatin structure. Understanding the intricate interplay between cytokine-mediated signalling pathways in keratinocytes and the resulting epigenetic changes is essential for elucidating the pathogenesis of AD. In this study, we utilized high-throughput technology to examine the effects of cytokines on modulation of the epigenetic landscape at the keratinocyte single-cell level, and subsequent effects on the gene expression. Methods We utilized the reconstructed human epidermis model, an in vitro three-dimensional human epidermis model consisting of a polycarbonate membrane and keratinocytes mimicking the structure of native human epidermis. Following exposure to AD cytokine(s), the model gene expression and chromatin accessibility of target cells were analysed using single-cell multiomics approaches. Results Our preliminary data show that IL-4, IL-13 and IL-22 reduce the expression levels of the barrier-related gene filaggrin in keratinocytes. Conclusions Unlike genetic changes, epigenetic alterations are dynamic and can be restored to their normal state, which has major implications for the development of therapeutics for various diseases. This study will provide valuable insights into the epigenetic mechanisms underlying AD and present potential targets for epigenetic-related therapeutic interventions. These interventions can be used in combination with available compounds to reduce the recurrence of AD and improve the treatment efficiency.

Matricellular proteins: Potential biomarkers in head and neck cancer

AbstractThe extracellular matrix (ECM) is a complex network of diverse multidomain macromolecules, including collagen, proteoglycans, and fibronectin, that significantly contribute to the mechanical properties of tissues. Matricellular proteins (MCPs), as a family of non‐structural proteins, play a crucial role in regulating various ECM functions. They exert their biological effects by interacting with matrix proteins, cell surface receptors, cytokines, and proteases. These interactions govern essential cellular processes such as differentiation, proliferation, adhesion, migration as well as multiple signal transduction pathways. Consequently, MCPs are pivotal in maintaining tissue homeostasis while orchestrating intricate molecular mechanisms within the ECM framework. The expression level of MCPs in adult steady‐state tissues is significantly low; however, under pathological conditions such as inflammation and cancer, there is a substantial increase in their expression. In recent years, an increasing number of studies have focused on elucidating the role and significance of MCPs in the development and progression of head and neck cancer (HNC). During HNC progression, there is a remarkable upregulation in MCP expression. Through their distinctive structure and function, they actively promote tumor growth, invasion, epithelial‐mesenchymal transition, and lymphatic metastasis of HNC cells. Moreover, by binding to integrins and modulating various signaling pathways, they effectively execute their biological functions. Furthermore, MCPs also hold potential as prognostic indicators. Although the star proteins of various MCPs have been extensively investigated, there remains a plethora of MCP family members that necessitate further scrutiny. This article comprehensively examines the functionalities of each MCP and highlights the research advancements in the context of HNC, with an aim to identify novel biomarkers for HNC and propose promising avenues for future investigations.

Molecular Cloning, Characterization, and Expression of a Receptor for Activated Protein Kinase C1 (RACK1) Gene in Exopalaemon carinicauda Zoea Larvae under Aroclor 1254 Stress.

The receptor for activated protein kinase C1 (RACK1) belongs to the typical WD repeat family, which is extremely conservative and important in multiple signal transduction pathways related to growth and development that coordinate the intracellular role of various life activities. As a novel protein with versatile functions, it was found in a variety of organisms. In a previous study, we identified the RACK1 sequence of white shrimp from transcriptome data. In this study, we employed specialized bioinformatics software to conduct an in-depth analysis of EcRACK1 and compare its amino acid sequence homology with other crustaceans. Furthermore, we investigated the expression patterns of RACK1 at different developmental stages and tissues, as well as at various time points after exposure to Aroclor 1245, aiming to elucidate its function and potential response towards Aroclor 1245 exposure. The length of EcRACK1 is 957 nucleotides, which encodes 318 amino acids. Moreover, there were seven typical WD repeats in EcRACK1, which have more than a 96% sequence identity with the RACK1 proteins of Penaeus. The results of tissue expression and spatiotemporal expression showed that it was significantly increased in the II and IV stages, but had a significant tissue specificity in the hepatopancreas, spermary, and muscle tissues of E. carinicauda, adult stage. Compared to the control, EcRACK1 was significantly induced in E. carinicauda zoea larvae exposed to Aroclor 1254 for 6, 10, 20, and 30 d (p < 0.05). These results suggested that EcRACK1 may play an important role in the larval development and environmental defense of E. carinicauda.

Deciphering Early-Stage Molecular Mechanisms of Negative Pressure Wound Therapy in a Murine Model.

Negative Pressure Wound Therapy (NPWT) is a commonly employed clinical strategy for wound healing, yet its early-stage mechanisms remain poorly understood. To address this knowledge gap and overcome the limitations of human trials, we establish an NPWT C57BL/6JNarl mouse model to investigate the molecular mechanisms involved in NPWT. In this study, we investigate the intricate molecular mechanisms through which NPWT expedites wound healing. Our focus is on NPWT's modulation of inflammatory immune responses and the concurrent orchestration of multiple signal transduction pathways, resulting in shortened coagulation time and reduced inflammation. Notably, we observe a significant rise in dickkopf-related protein 1 (DKK-1) concentration during NPWT, promoting the differentiation of Hair Follicle Stem Cells (HFSCs) into epidermal cells, expediting wound closure. Under negative pressure, macrophages express and release DKK-1 cytokines, crucial for stimulating HFSC differentiation, as validated in animal experiments and in vitro studies. Our findings illuminate the inflammatory dynamics under NPWT, revealing potential signal transduction pathways. The proposed framework, involving early hemostasis, balanced inflammation, and macrophage-mediated DKK-1 induction, provides a novel perspective on enhancing wound healing during NPWT. Furthermore, these insights lay the groundwork for future pharmacological advancements in managing extensive wounds, opening avenues for targeted therapeutic interventions in wound care.

Understanding the Role of Galectin-1 in Heart Failure: A Comprehensive Narrative Review.

Heart failure (HF) is the fastest-growing cardiovascular condition worldwide. The immune system may play a role in the development of HF since this condition is associated with elevated pro-inflammatory cytokine levels. HF is a life-threatening disease, and there is an increasing demand for diagnostic biomarkers, prognostic factors, and therapeutic agents that can help treat it. Galectin-1 (Gal-1) is the prototype galectin of the lectin family. Multiple signal transduction pathways are regulated by Ras proteins, which act as a molecular switch in cells. Gal-1 regulates T and B cell activation, differentiation, and survival. Gal-1 has been linked to inflammation. Activated T cells produce Gal-1 through an autocrine apoptotic mechanism involving MEK1/ERK and p38 MAPK. In the cardiovascular system, atherosclerosis is facilitated by Gal-1. Heart disease, myocardial infarction, hypertension, and stroke can be caused by atherosclerotic plaque. HF and heart hypertrophy are caused by decreased cardiac L-type Ca2+ channel activity. Deregulation of Gal-1 and CaV1.2 in pathological cardiac hypertrophy suggests a possible target for anti-hypertrophic therapy. Rat hypertrophic cardiomyocytes express Gal-1 and CaV1.2 channels simultaneously. It has been reported that diastolic dysfunction (DD) is associated with elevated Gal-1 levels. The high Gal-1 level in subjects led to the lowest cumulative survival as a composite endpoint. Incidences of HF, DD, and serum Gal-1 levels correlated significantly. The ejection fraction was negatively correlated with Gal-1 and CRP concentrations. Based on two different approaches in mice and humans, Gal-1 was identified as a potential mediator of HF.

A First-in-Human, Open-Label, Phase I Dose Escalation Trial of Daily Oral Nmt Inhibitor Zelenirstat in Patients with Relapsed/Refractory B-Cell Lymphomas and Advanced Solid Tumors

Background Myristoylation, the N-terminal modification of proteins with the fatty acid myristate, regulates multiple membrane-bound signal transduction pathways driving cancer cell biology. This modification is catalyzed by two N-myristoyltransferases (NMT), NMT1 and NMT2. Aberrant NMT expression has been identified in cancer cells and inhibition of myristoylation represents a novel anticancer treatment strategy. Zelenirstat (PCLX-001) is an oral, highly bioavailable, small molecule NMT inhibitor with strong affinity for both NMT1 and NMT2 proteins (IC 50 of 5nM and 8nM, respectively). In vitro hematologic cancer cell lines were exquisitely sensitive to zelenirstat. Zelenirstat regressed subcutaneous tumors in xenograft models derived from lymphoma cell lines, as well as in a refractory DLBCL patient (pt) derived xenograft model. Zelenirstat also demonstrated anticancer activity in multiple solid tumor xenograft models. Based on pre-clinical data, we conducted a phase I dose escalation trial to determine safety, tolerability, maximum tolerated dose (MTD), and pharmacokinetics (PK) of zelenirstat. Methods Pts with relapsed/refractory (R/R) B-cell lymphomas and advanced solid tumors were enrolled in a multicenter, open label, standard phase I dose escalation trial of once daily (OD) oral zelenirstat, administered in 28-day cycles until progressive disease or unacceptable toxicity. Seven dose levels were studied: 20 mg, 40 mg, 70 mg, 100 mg, 140 mg, 210 mg, and 280 mg. Dose limiting toxicity (DLT), attributable to zelenirstat during cycle 1, was defined as: grade (Gr) 4 thrombocytopenia, Gr 3 thrombocytopenia with bleeding, Gr 4 neutropenia ≥ 7 days, febrile neutropenia, clinically significant &amp;gt; Gr 3 non-hematologic toxicity, or any significant toxicity warranting a hold of zelenirstat. Plasma PK were obtained on C1D1, C1D15, and trough concentrations C1D2, C1D16 and prior to each subsequent cycle. Response assessments occurred every 2 cycles to determine best overall response. Results Between Sept 2021 and Jul 2023, 21 DLT-evaluable pts [4 R/R B-cell lymphoma (3 DLBCL, 1 FL grade 3b); 17 advanced solid tumor (7 colorectal, 2 pancreas, 2 ovarian, 1 each of sarcoma, NSCLC, pleural mesothelioma, melanoma, CUP, bladder)] received zelenirstat at doses ranging from 20 mg OD to 280 mg OD. Dose escalation occurred without DLT until the 280 mg cohort where two DLTs were reported: a bladder carcinoma pt who developed nausea, vomiting, and drug-induced fever necessitating a hold of zelenirstat and a colorectal cancer (CRC) pt who had Gr 3 dehydration from nausea, vomiting, diarrhea, and oral mucositis. The maximal administered dose was 280 mg OD and the presumptive MTD was 210 mg OD. Drug compliance was high, and of 3 pts within the 210 mg cohort, none required dose reduction. Common treatment-emergent all-grade adverse events (AEs) at doses up to the 210 mg cohort were gastrointestinal and reported in 29% of pts. These were primarily diarrhea, nausea, or vomiting. Gr 2 thrombocytopenia occurred in 17% of patients. No other AEs were seen at a frequency of &amp;gt; 5%. There were no AEs of neuropathy, alopecia, or QT interval prolongation. Noncompartmental PK analyses demonstrated rapid oral absorption, a terminal half-life of approximately 10 hrs, rapid achievement of steady state, and no induction of metabolism. Zelenirstat trough plasma concentrations at 100 mg, 140 mg, and 210 mg doses markedly exceeded the EC 90 required to inhibit cultured cancer cells. Stable disease as best response was seen in five patients (pancreas at 40 mg; CRC at 140 mg; and two ovarian and one CRC at 210 mg). At the 210 mg dose, one of the ovarian cancer pts had a corresponding reduction of CA-125 (20%) while the CRC pt had a reduction in CEA (50%). Conclusions Zelenirstat is safe and well tolerated up to the 210 mg OD dose, which we have established as the presumptive MTD. Additional pts, including a phase IIA study in pts with R/R B-cell NHL, are accruing at this dose for further safety and activity exploration. The absence of severe toxicities, attainment of plasma concentrations highly active in preclinical models, and early evidence of antitumor activity support the ongoing development of zelenirstat for pts with R/R B-cell lymphomas and advanced solid tumors.

Flavones provide resistance to DUX4-induced toxicity via an mTor-independent mechanism

Facioscapulohumeral muscular dystrophy (FSHD) is among the most common of the muscular dystrophies, affecting nearly 1 in 8000 individuals, and is a cause of profound disability. Genetically, FSHD is linked to the contraction and/or epigenetic de-repression of the D4Z4 repeat array on chromosome 4, thereby allowing expression of the DUX4 gene in skeletal muscle. If the DUX4 transcript incorporates a stabilizing polyadenylation site the myotoxic DUX4 protein will be synthesized, resulting in muscle wasting. The mechanism of toxicity remains unclear, as many DUX4-induced cytopathologies have been described, however cell death does primarily occur through caspase 3/7-dependent apoptosis. To date, most FSHD therapeutic development has focused on molecular methods targeting DUX4 expression or the DUX4 transcript, while therapies targeting processes downstream of DUX4 activity have received less attention. Several studies have demonstrated that inhibition of multiple signal transduction pathways can ameliorate DUX4-induced toxicity, and thus compounds targeting these pathways have the potential to be developed into FSHD therapeutics. To this end, we have screened a group of small molecules curated based on their reported activity in relevant pathways and/or structural relationships with known toxicity-modulating molecules. We have identified a panel of five compounds that function downstream of DUX4 activity to inhibit DUX4-induced toxicity. Unexpectedly, this effect was mediated through an mTor-independent mechanism that preserved expression of ULK1 and correlated with an increase in a marker of active cellular autophagy. This identifies these flavones as compounds of interest for therapeutic development, and potentially identifies the autophagy pathway as a target for therapeutics.

Enhanced Ca2+ binding to EF-hands through phosphorylation of conserved serine residues activates MpRBOHB and chitin-triggered ROS production.

NADPH oxidases/RBOHs catalyze apoplastic ROS production and act as key signaling nodes, integrating multiple signal transduction pathways regulating plant development and stress responses. Although RBOHs have been suggested to be activated by Ca2+ binding and phosphorylation by various protein kinases, a mechanism linking Ca2+ binding and phosphorylation in the activity regulation remained elusive. Chitin-triggered ROS production required cytosolic Ca2+ elevation and Ca2+ binding to MpRBOHB in a liverwort Marchantia polymorpha. Heterologous expression analysis of truncated variants revealed that a segment of the N-terminal cytosolic region highly conserved among land plant RBOHs encompassing the two EF-hand motifs is essential for the activation of MpRBOHB. Within the conserved regulatory domain, we have identified two Ser residues whose phosphorylation is critical for the activation in planta. Isothermal titration calorimetry analyses revealed that phosphorylation of the two Ser residues increased the Ca2+ binding affinity of MpRBOHB, while Ca2+ binding is indispensable for the activation, even if the two Ser residues are phosphorylated. Our findings shed light on a mechanism through which phosphorylation potentiates the Ca2+ -dependent activation of MpRBOHB, emphasizing the pivotal role of Ca2+ binding in mediating the Ca2+ and phosphorylation-driven activation of MpRBOHB, which is likely to represent a fundamental mechanism conserved among land plant RBOHs.

The implication of viability and pathogenicity by truncated lipopolysaccharide in Yersinia enterocolitica.

The fast envelope stress responses play a key role in the transmission and pathogenesis of Yersinia enterocolitica, one of the most common foodborne pathogens. Our previous study showed that deletion of the waaF gene, essential for the biosynthesis of lipopolysaccharide (LPS) core polysaccharides, led to the formation of a truncated LPS structure and induced cell envelope stress. This envelope stress may disturb the intracellular signal transduction, thereby affecting the physiological functions of Y. enterocolitica. In this study, truncated LPS caused by waaF deletion was used as a model of envelope stress in Y. enterocolitica. We investigated the mechanisms of envelope stress responses and the cellular functions affected by truncated LPS. Transcriptome analysis and phenotypic validation showed that LPS truncation reduced flagellar assembly, bacterial chemotaxis, and inositol phosphate metabolism, presenting lower pathogenicity and viability both in vivo and in vitro environments. Further 4D label-free phosphorylation analysis confirmed that truncated LPS perturbed multiple intracellular signal transduction pathways. Specifically, a comprehensive discussion was conducted on the mechanisms by which chemotactic signal transduction and Rcs system contribute to the inhibition of chemotaxis. Finally, the pathogenicity of Y. enterocolitica with truncated LPS was evaluated in vitro using IPEC-J2 cells as models, and it was found that truncated LPS exhibited reduced adhesion, invasion, and toxicity of Y. enterocolitica to IPEC-J2 cells. Our research provides an understanding of LPS in the regulation of Y. enterocolitica viability and pathogenicity and, thus, opening new avenues to develop novel food safety strategies or drugs to prevent and control Y. enterocolitica infections. KEY POINTS: • Truncated LPS reduces flagellar assembly, chemotaxis, and inositol phosphate metabolism in Y. enterocolitica. • Truncated LPS reduces adhesion, invasion, and toxicity of Y. enterocolitica to IPEC-J2 cells. • Truncated LPS regulates intracellular signal transduction of Y. enterocolitica.

Conformational and functional regulation of the chicken tumor virus number 10 (CT10) regulator of kinase II (CrkII) adaptor protein by cyclophilin A

The Src homology 2 (SH2) and SH3 domain-containing chicken tumor virus number 10 (CT10) regulator of kinase (Crk) adaptor proteins include three cellular members that serve as integral constituents of multiple receptor-linked signal transduction pathways. CrkI and CrkII are products of alternative RNA-splicing which is transcribed from a single gene, while Crk-like (CrkL), which is highly homologous to CrkII, is encoded by a different gene. Thanks to their modular structure, the Crk adaptor proteins can simultaneously interact with activated receptors and a wide range of effector molecules, and orchestrate the assembly of complexes containing enzymes and substrates at the receptor site. They are involved in the regulation of a large number of cellular processes which control cell growth, differentiation, transformation, and apoptosis. Cell activation-dependent tyrosine phosphorylation of CrkII and CrkL serves as a major posttranslational modification mechanism that introduces conformational changes in the proteins by promoting an intramolecular interaction between the phosphotyrosine and the self SH2 domain. The resulting conformational change induces downregulation of CrkII- and CrkL-dependent biological processes. A second type of posttranslational modification mechanism regulates the structure and function of the CrkII adaptor protein by immunophilin-mediated protein isomerization. Two of the most abundant immunophilins in T lymphocytes which function as peptidyl-prolyl cis-trans isomerases (PPIases), namely cyclophilin A (CypA) and FK506-binding proteins (FKBPs), can associate with CrkII and catalyze its reciprocal cis-trans isomerization. This mechanism is of special importance for the regulation of T lymphocyte functions and for T cell-mediated immune responses, since immunophilin inhibitors, such as cyclosporin A (CsA) and FK506, function as immunosuppressive drugs that can prevent allotransplanted graft rejection. The present manuscript focuses on selected functions of Crk adaptor proteins, predominantly in T lymphocytes, and reviews in more detail the current knowledge on the immunophilin-dependent regulation of the structure and function of the CrkII adaptor protein.

Extracellular vesicle microRNA-mediated transcriptional regulation may contribute to dementia with Lewy bodies molecular pathology.

Dementia with Lewy bodies (DLB) is the second most common dementia. Advancing our limited understanding of its molecular pathogenesis is essential for identifying novel biomarkers and therapeutic targets for DLB. DLB is an α-synucleinopathy, and small extracellular vesicles (SEV) from people with DLB can transmit α-synuclein oligomerisation between cells. Post-mortem DLB brains and serum SEV from those with DLB share common miRNA signatures, and their functional implications are uncertain. Hence, we aimed to investigate potential targets of DLB-associated SEV miRNA and to analyse their functional implications. We identified potential targets of six previously reported differentially expressed miRNA genes in serum SEV of people with DLB (MIR26A1, MIR320C2, MIR320D2, MIR548BA, MIR556, and MIR4722) using miRBase and miRDB databases. We analysed functional implications of these targets using EnrichR gene set enrichment analysis and analysed their protein interactions using Reactome pathway analysis. These SEV miRNA may regulate 4278 genes that were significantly enriched among the genes involved in neuronal development, cell-to-cell communication, vesicle-mediated transport, apoptosis, regulation of cell cycle, post-translational protein modifications, and autophagy lysosomal pathway, after Benjamini-Hochberg false discovery rate correction at 5%. The miRNA target genes and their protein interactions were significantly associated with several neuropsychiatric disorders and with multiple signal transduction, transcriptional regulation, and cytokine signalling pathways. Our findings provide in-silico evidence that potential targets of DLB-associated SEV miRNAs may contribute to Lewy pathology by transcriptional regulation. Experimental validation of these dysfunctional pathways is warranted and could lead to novel therapeutic avenues for DLB.

Regulation, targets and functions of CSK.

The Src family kinases (SFK) plays an important role in multiple signal transduction pathways. Aberrant activation of SFKs leads to diseases such as cancer, blood disorders, and bone pathologies. By phosphorylating and inactivating SFKs, the C-terminal Src kinase (CSK) serves as the key negative regulator of SFKs. Similar to Src, CSK is composed of SH3, SH2, and a catalytic kinase domain. However, while the Src kinase domain is intrinsically active, the CSK kinase domain is intrinsically inactive. Multiple lines of evidence indicate that CSK is involved in various physiological processes including DNA repair, permeability of intestinal epithelial cells (IECs), synaptic activity, astrocyte-to-neuron communication, erythropoiesis, platelet homeostasis, mast cell activation, immune and inflammation responses. As a result, dysregulation of CSK may lead to many diseases with different underlying molecular mechanisms. Furthermore, recent findings suggest that in addition to the well-established CSK-SFK axis, novel CSK-related targets and modes of CSK regulation also exist. This review focuses on the recent progress in this field for an up-to-date understanding of CSK.

ATM phosphorylates the FATC domain of DNA-PKcs at threonine 4102 to promote non-homologous end joining.

Ataxia-telangiectasia mutated (ATM) drives the DNA damage response via modulation of multiple signal transduction and DNA repair pathways. Previously, ATM activity was implicated in promoting the non-homologous end joining (NHEJ) pathway to repair a subset of DNA double-stranded breaks (DSBs), but how ATM performs this function is still unclear. In this study, we identified that ATM phosphorylates the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a core NHEJ factor, at its extreme C-terminus at threonine 4102 (T4102) in response to DSBs. Ablating phosphorylation at T4102 attenuates DNA-PKcs kinase activity and this destabilizes the interaction between DNA-PKcs and the Ku-DNA complex, resulting in decreased assembly and stabilization of the NHEJ machinery at DSBs. Phosphorylation at T4102 promotes NHEJ, radioresistance, and increases genomic stability following DSB induction. Collectively, these findings establish a key role for ATM in NHEJ-dependent repair of DSBs through positive regulation of DNA-PKcs.

Investigation of the potential pharmacological mechanism of action of Danhong injection against chronic heart failure using a network pharmacol ogy based approach

Purpose: To investigate the mechanism of action of Danhong Injection (DHI) in chronic heart failure (CHF).&#x0D; Methods: Network pharmacology was employed to identify the bioactive compounds and targets of DHI in CHF. Bioinformatics analysis was used to examine the potential biological functions and pathways of the candidate targets, while molecular docking was conducted to evaluate the binding affinity of the ligand-protein complex.&#x0D; Results: Based on data mining from public databases, 65 bioactive ingredients and 246 potential targets of DHI were identified, along with 786 CHF-related genes. There were 48 common targets between DHI targets and CHF-related genes, and a protein-protein interaction (PPI) network of common targets containing 42 nodes and 204 edges was constructed. The 48 common targets were considered as effector proteins exerting anti-CHF effects, and they were shown to be involved in multiple signal-transduction pathways and disease-related pathways by bioinformatics analysis. Most of these targets had protein-binding capability and were located in plasma membrane as well as extracellular regions. The biological process of these proteins was primarily associated with gene regulation, response to hypoxia, and heart development. Binding capability between these active ingredients and proteins was further validated by molecular docking simulation.&#x0D; Conclusion: This study has shed new light on the pharmacological mechanism of action of DHI’s effects on CHF, thus offering fresh leads for additional research into DHI's potential to cure CHF.

A first-in-human, open-label, phase I trial of daily oral PCLX-001, an NMT inhibitor, in patients with relapsed/refractory B-cell lymphomas and advanced solid tumors.

e15094 Background: Myristoylation, the N-terminal modification of proteins with the fatty acid myristate, regulates multiple membrane-bound signal transduction pathways driving cancer cell biology. This modification is catalyzed by two N-myristoyltransferases (NMT), NMT1 and NMT2. Aberrant NMT expression has been identified in cancer cells and inhibition of myristoylation represents a novel anticancer treatment strategy. PCLX-001 is an oral, highly bioavailable, small molecule NMT inhibitor with strong affinity for both NMT1 and NMT2 proteins (IC50 of 5nM and 8nM, respectively). In vitro, hematologic cancer cell lines were exquisitely sensitive to PCLX-001. PCLX-001 regressed subcutaneous tumors in xenograft models derived from lymphoma cell lines, as well as in a refractory DLBCL patient derived xenograft model. PCLX-001 also demonstrated anticancer activity in multiple solid tumor xenograft models. Based on pre-clinical data, we hypothesized that PCLX-001 would be safe, tolerable, and active as a novel oral cancer therapeutic. Methods: Patients with relapsed/refractory B-cell lymphomas and advanced solid tumors are being enrolled in a multicenter, open label, standard phase I dose escalation design to determine feasibility, maximum tolerated dose (MTD), and pharmacokinetics of PCLX-001 monotherapy. Seven dose levels are being studied: 20 mg, 40 mg, 70 mg, 100 mg, 140 mg, 200 mg, and 280 mg. Dose limiting toxicity (DLT) is defined as: grade (Gr) 4 platelets, Gr 3 platelets with bleeding, Gr 4 ANC ≥ 7 days, febrile neutropenia, or clinically significant &gt; Gr 3 non-hematologic toxicity. Results: Eighteen evaluable patients (3 relapsed B-cell lymphoma; 15 advanced solid tumor) have been accrued through dose level six (200 mg cohort) without DLT. No attributable Gr 3 or 4 toxicities have been identified. Noncompartmental pharmacokinetic (PK) analyses demonstrate rapid oral absorption, a terminal half-life of approximately 10 hours, rapid achievement of steady state, and no induction of metabolism. PCLX-001 trough plasma concentrations at higher dose cohorts exceed the EC90 required to inhibit cultured cancer cells. Conclusions: PCLX-001 is safe and well tolerated up to the 200 mg daily dose. Our results support the ongoing development of PCLX-001 as an oral daily therapy for the treatment of patients with cancer. Updated study results will be presented, summarizing the safety, MTD, and PK outcomes in PCLX-001 treated patients. Preliminary clinical activity will be determined in 20 patient dose expansion cohorts of relapsed/refractory B-cell lymphomas, and selected advanced solid tumors following the identification of PCLX-001 MTD. Clinical trial information: NCT04836195 .

Expression characteristics and their functional role of IGFBP gene family in pan-cancer

BackgroundInsulin-like growth factor binding proteins (IGFBPs) are critical regulators of the biological activities of insulin-like growth factors. The IGFBP family plays diverse roles in different types of cancer, which we still lack comprehensive and pleiotropic understandings so far.MethodsMulti-source and multi-dimensional data, extracted from The Cancer Genome Atlas (TCGA), Oncomine, Cancer Cell Line Encyclopedia (CCLE), and the Human Protein Atlas (HPA) was used for bioinformatics analysis by R language. Immunohistochemistry and qRT-PCR were performed to validate the results of the database analysis results. Bibliometrics and literature review were used for summarizing the research progress of IGFBPs in the field of tumor.ResultsThe members of IGFBP gene family are differentially expressed in various cancer types. IGFBPs expression can affect prognosis of different cancers. The expression of IGFBPs expression is associated with multiple signal transduction pathways. The expression of IGFBPs is significantly correlated with tumor mutational burden, microsatellite instability, tumor stemness and tumor immune microenvironment. The qRT-PCR experiments verified the lower expression of IGFBP2 and IGFBP6 in gastric cancer and the lower expression of IGFBP6 in colorectal cancer. Immunohistochemistry validated a marked downregulation of IGFBP2 protein in gastric cancer tissues. The keywords co-occurrence analysis of IGFBP related publications in cancer showed relative research have been more concentrating on the potential of IGFBPs as tumor diagnostic and prognostic markers and developing cancer therapies.ConclusionsThese findings provide frontier trend of IGFBPs related research and new clues for identifying novel therapeutic targets for various cancers.

TRAF7 negatively regulates the RLR signaling pathway by facilitating the K48-linked ubiquitination of TBK1

TANK-binding kinase 1 (TBK1) is a nodal protein involved in multiple signal transduction pathways. In RNA virus-mediated innate immunity, TBK1 is recruited to the prion-like platform formed by MAVS and subsequently activates the transcription factors IRF3/7 and NF-κB to produce type I interferon (IFN) and proinflammatory cytokines for the signaling cascade. In this study, TRAF7 was identified as a negative regulator of innate immune signaling. TRAF7 interacts with TBK1 and promotes K48-linked polyubiquitination and degradation of TBK1 through its RING domain, impairing the activation of IRF3 and the production of IFN-β. In addition, we found that the conserved cysteine residues at position 131 of TRAF7 are necessary for its function toward TBK1. Knockout of TRAF7 could facilitate the activation of IRF3 and increase the transcript levels of downstream antiviral genes. These data suggest that TRAF7 negatively regulates innate antiviral immunity by promoting the K48-linked ubiquitination of TBK1.

Abstract 1855: Targeting DGKA for immuno-oncology therapy: ISM4312A, a novel DGKA inhibitor with robust anti-tumor activity

Abstract Diacylglycerol kinases (DGKs), a family of isozymes that phosphorylate the membrane lipid, diacylglycerol (DAG), to phosphatidic acid (PA), are important players in signal transduction cascades. DAG and PA act as vital second messengers that regulate multiple cellular signal transduction pathways including PKC and MAPK. DGKα (DGKA), one of the ten human DGK isoforms, has been reported to play a role in mediating numerous aspects of cancer progression including survival, migration, and invasion of cancer cells. Emerging data indicate that DGKA mediates T-cell dysfunction during anti-PD-1 therapy, playing a role in the development of resistance to PD-1 blockade. This suggests that DGKA inhibition offers a promising strategy to improve the efficacy of immunotherapy in the treatment of cancer. Although serotonin (5-HT) antagonists ritanserin, R59022 and R59949 have been previously repurposed as DGKA inhibitors, their potency and selectivity profiles are largely unsatisfactory. Therefore, there is a significant unmet clinical need to develop potent and selective DGKA inhibitors. Here, we used our proprietary PandaOmics platform to explore targets that can overcome the resistance to anti-PD1 therapy. In order to do so, we created a project that included bulk RNAseq data from 4 datasets alongside with 2 single-cell RNAseq datasets. Based on the calculation results, DGKA inhibitors may overcome anti-PD-1 resistance and expand the responder patient population in cancer immunotherapy. We then designed and evaluated a series of compounds in biochemical and cellular assays, and report that ISM4312A is a novel DGKA inhibitor with excellent potency (IC50 of 120 pM) and high selectivity (&amp;gt;25000 fold) for DGKA versus 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT2B. Further, ISM4312A showed high selectivity against 468 other kinases. In the cellular T-cell activation assay, ISM4312A induced IL-2 production in a dose-dependent manner and enhanced T-cell activity at concentrations as low as 20 nM. In the MC38 in vivo syngeneic model, ISM4312A at 3 mg/kg BID showed robust anti-tumor activities with (Tumor Growth Inhibition, TGI, 93.4%, 37.5% mice achieved CR) or without (TGI, 25.2%) anti-PD-1 therapy. Data from this combination study indicate synergistic activity as compared with the single anti-PD-1 treatment (TGI, 50.8% at 5 mg/kg BID, no mice achieved CR). ISM4312A also exhibited favorable ADME, excellent oral bioavailability, and tolerance. Together, the data support the ongoing clinical development of ISM4312A as a potential first-in-class DGKA inhibitor in cancer immunotherapy. Citation Format: Deheng Sun, Hongfu Lu, Huaxing Yu, Feng Wang, Mike Korzinkin, Xin Cai, Xiao Ding, Sujata Rao, Feng Ren, Alex Zhavoronkov. Targeting DGKA for immuno-oncology therapy: ISM4312A, a novel DGKA inhibitor with robust anti-tumor activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1855.