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Interleukin‐1 receptor–associated kinase 4 (IRAK4), a key component of the Myddosome complex, mediates signaling through toll‐like and interleukin‐1 receptors. KT‐474, a heterobifunctional IRAK4 degrader, was evaluated in a randomized, double‐blind, placebo‐controlled Phase 1 trial (NCT04772885) in single (25, 75, 150, 300, 600, 1000, and 1600 mg) and multiple (25, 50, 100, and 200 mg once daily [QD] for 14 days; or 200 mg twice weekly) ascending doses in healthy subjects. The pharmacokinetics of KT‐474 and its diastereomers, the pharmacodynamics of KT‐474, and the effect of food on KT‐474 pharmacokinetics and the pharmacokinetic–pharmacodynamic analysis are presented as additional analyses to supplement the Ackerman et al. publication. KT‐474 showed delayed absorption and prolonged elimination. Plasma exposure increased less than dose‐proportionally, with single‐dose exposure plateauing after the 1000 mg dose. Steady state was achieved after 7 days of daily dosing and resulted in a 3‐ to 4‐fold accumulation in exposure. A significant food effect was observed at the 600 mg dose, with exposure increasing up to 2.57‐fold when KT‐474 was administered with a high‐fat meal. Urinary excretion of KT‐474 was < 1%. KT‐474 demonstrated robust IRAK4 degradation in blood, with mean reductions of up to 98% observed at the 50–200 mg QD doses, as well as inhibition of ex vivo induction of a broad array of cytokines and chemokines by stimulants lipopolysaccharides and R848. Analysis of the relationship between plasma KT‐474 concentration and IRAK4 reduction in blood indicated that plasma concentrations of 4.1–5.3 ng/mL would yield 80% IRAK4 reductions.

Multiple p38 MAP kinase inhibitors have been developed for the treatment of inflammatory diseases such as rheumatoid arthritis, but their effectiveness has been limited due to toxicity and tachyphylaxis, leading to a lack of clinical benefit. Efforts have been made to circumvent this limitation by targeting individual substrates downstream of p38, including MK2 and MK5. This approach has failed to yield clinical benefit despite preclinical evidence of a therapeutic effect. We hypothesized that there is redundancy in the MAPK activating kinase family that would necessitate blocking multiple kinases to sufficiently impact inflammatory processes. We used heterobifunctional protein degraders that either specifically degraded MK2 selectively or degraded MK2/3/5 simultaneously to test the hypothesis, in addition to genetic approaches to enable knockdown. In human PBMCs, elimination of MK2/3/5 with heterobifunctional degraders resulted in full reduction of TLR4 or TLR7/8 induced TNFα, whereas MK2-specific degradation only attenuated TNFα biosynthesis. In contrast, both specific MK2 degradation and broad MK2/3/5 degradation inhibited TGF-β-induced collagen production in human fibroblasts. This observation was consistent with genetic deletions of MK2, MK3 and MK5 (singly and in combination) whereby single deletion of MK2, MK3 or MK5 attenuated lipopolysaccharide (LPS) induced TNFα production and had no effect on R848-induced TNFα production. Double deletion of MK2 and MK3 or MK2 and MK5 or MK2/3/5 triple deletion had a significantly greater effect on TNFα production regardless of stimulus. The combined data suggest cooperativity between MK2 and either MK3 or MK5 for efficient, cell context-dependent modulation of inflammatory responses.

Recent studies suggest that lysophosphatidic acid (LPA) and its G protein-coupled receptors (GPCRs) LPA1, LPA2, or LPA3may play a role in the development of several types of cancers, including colorectal cancer. However, the specific receptor subtype(s) and their signal-transduction pathways responsible for LPA-induced cancer cell proliferation have not been fully elucidated. We show by specific RNA interference (RNAi) that LPA2and LPA3but not LPA1are targets for LPA-induced proliferation of HCT116 and LS174T colon cancer cells. We determined that LPA-induced colon cancer cell proliferation requires the β-catenin signaling pathway, because knockdown of β-catenin by RNAi abolished LPA-induced proliferation of HCT116 cells. Moreover, LPA activates the main signaling events in the β-catenin pathway: phosphorylation of glycogen synthase kinase 3β (GSK3β), nuclear translocation of β-catenin, transcriptional activation of T cell factor (Tcf)/lymphoidenhancer factor (Lef), and expression of target genes. Inhibition of conventional protein kinase C (cPKC) blocked the effects, suggesting its involvement in LPA-induced activation of the β-catenin pathway. Thus, LPA2and LPA3signal the proliferation of colon cancer cells through cPKC-mediated activation of the β-catenin pathway. These results link LPA and its GPCRs to cancer through a major oncogenic signaling pathway.

TASK3 gene (Kcnk9) is amplified and overexpressed in several types of human carcinomas. In this report, we demonstrate that a point mutation (G95E) within the consensus K+filter of TASK3 not only abolished TASK3 potassium channel activity but also abrogated its oncogenic functions, including proliferation in low serum, resistance to apoptosis, and promotion of tumor growth. Furthermore, we provide evidence that TASK3G95Eis a dominant-negative mutation, because coexpression of the wild-type and the mutant TASK3 resulted in inhibition of K+current of wild-type TASK3 and its tumorigenicity in nude mice. These results establish a direct link between the potassium channel activity of TASK3 and its oncogenic functions and imply that blockers for this potassium channel may have therapeutic potential for the treatment of cancers.

Metastasis of primary tumors leads to a very poor prognosis for patients suffering from cancer. Although it is well established that not every tumor will eventually metastasize, it is less clear whether primary tumors acquire genetic alterations in a stochastic process at a late stage, which make them invasive, or whether genetic alterations acquired early in the process of tumor development drive primary tumor growth and determine whether this tumor is going to be metastatic. To address this issue, we tested genes identified in a large-scale comparative genomic hybridization analysis of primary tumor for their ability to confer metastatic properties on a cancer cell. We identified amplification of the ACK1 gene in primary tumors, which correlates with poor prognosis. We further show that overexpression of Ack1 in cancer cell lines can increase the invasive phenotype of these cells both in vitro and in vivo and leads to increased mortality in a mouse model of metastasis. Biochemical studies show that Ack1 is involved in extracellular matrix-induced integrin signaling, ultimately activating signaling processes like the activation of the small GTPase Rac. Taken together, this study supports a theory from Bernards and Weinberg [Bernards, R. & Weinberg, R. A. (2002) Nature 418, 823], which postulates that the tendency to metastasize is largely predetermined.

Toll-like receptor–driven and interleukin-1 (IL-1) receptor–driven inflammation mediated by IL-1 receptor–associated kinase 4 (IRAK4) is involved in the pathophysiology of hidradenitis suppurativa (HS) and atopic dermatitis (AD). KT-474 (SAR444656), an IRAK4 degrader, was studied in a randomized, double-blind, placebo-controlled phase 1 trial where the primary objective was safety and tolerability. Secondary objectives included pharmacokinetics, pharmacodynamics and clinical activity in patients with moderate to severe HS and in patients with moderate to severe AD. KT-474 was administered as a single dose and then daily for 14 d in 105 healthy volunteers (HVs), followed by dosing for 28 d in an open-label cohort of 21 patients. Degradation of IRAK4 was observed in HV blood, with mean reductions after a single dose of ≥93% at 600–1,600 mg and after 14 daily doses of ≥95% at 50–200 mg. In patients, similar IRAK4 degradation was achieved in blood, and IRAK4 was normalized in skin lesions where it was overexpressed relative to HVs. Reduction of disease-relevant inflammatory biomarkers was demonstrated in the blood and skin of patients with HS and patients with AD and was associated with improvement in skin lesions and symptoms. There were no drug-related infections. These results, from what, to our knowledge, is the first published clinical trial using a heterobifunctional degrader, provide initial proof of concept for KT-474 in HS and AD to be further confirmed in larger trials. ClinicalTrials.gov identifier: NCT04772885 . The heterobifunctional degrader KT-474 shows target engagement and is safe to use in healthy volunteers and in patients with hidradenitis suppurativa and patients with atopic dermatitis, and it exhibits preliminary efficacy in the improvement of skin lesions and symptoms in patients.

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by localized areas of demyelination 1 . Although the etiology and pathogenesis of MS remain largely unknown, it is generally assumed that immune responses to myelin antigens contribute to the disease process 1,2 . The exact sequence of events, as well as the molecular mediators that lead to myelin destruction, is yet to be defined 2,3 . As a potent mediator of inflammation, the cytopathic cytokine, tumor necrosis factor (TNF) has been considered to be a strong candidate in the pathogenesis of MS and its animal model, experimental autoimmune encephalomyelitis (EAE) 3–5 . However, its role in immune-mediated demyelination remains to be elucidated. To determine the contribution of TNF to the pathogenesis of the MS-like disease provoked by the myelin oligodendrocyte glycoprotein (MOG) 6 , we have tested mice with an homologous disruption of the gene encoding TNF (ref. 7). Here we report that upon immunization with MOG, mice lacking TNF develop severe neurological impairment with high mortality and extensive inflammation and demyelination. We show further that inactivation of the TNF gene converts MOG-resistant mice to a state of high susceptibility. Furthermore, treatment with TNF dramatically reduces disease severity in both TNF −/− mice and in other TNF +/+ mice highly susceptible to the MOG-induced disease. These findings indicate that TNF is not essential for the induction and expression of inflammatory and demyelinating lesions, and that it may limit the extent and duration of severe CNS pathology.

Abstract Preclinical human inflammatory bowel disease (IBD) mechanisms is one of 5 focus areas of the Challenges in IBD Research 2024 document, which also includes environmental triggers, novel technologies, precision medicine, and pragmatic clinical research. Herein, we provide a comprehensive overview of current gaps in inflammatory bowel diseases research that relate to preclinical research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in IBD interception, remission, and restoration. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders and represents a valuable resource for patient-centric research prioritization. This preclinical human IBD mechanisms section identifies major research gaps whose investigation will elucidate pathways and mechanisms that can be targeted to address unmet medical needs in IBD. Research gaps were identified in the following areas: genetics, risk alleles, and epigenetics; the microbiome; cell states and interactions; barrier function; IBD complications (specifically fibrosis and stricturing); and extraintestinal manifestations. To address these gaps, we share specific opportunities for investigation for basic and translational scientists and identify priority actions. Lay Summary To address the unmet medical needs of patients with inflammatory bowel diseases (IBD) and move toward cures, preclinical human-relevant research must center on mechanistic questions pertinent to patients with IBD in the 3 areas of disease interception, remission, and restoration.

T cells of tumor-bearing mice or cancer patients exhibit an immune dysfunction, enabling the tumor to escape immune surveillance. The experiments are based on EL4 thymoma cells that were transfected with costimulatory ligands B7-1, B7-2, or both at the same time. We used oligonucleotide-based DNA chip microarrays to characterize the genomic expression profile of peripheral T cells according to their anti-tumor immune response in vivo. These murine T cells were also characterized by ELISA, FACS analysis, and co-stimulatory assays. Using commonly established methods, such as FACS analysis or the analysis of the cytokine profile by ELISA, it was not possible to determine functional differences in the in vivo activity of T lymphocytes against tumor cells. EL4 tumor cells induced multiple anti-tumor immune responses in vivo depending on their B7 expression. We successfully used microarray analysis to identify genes that were differentially expressed in the dysfunctional T cells, which were unable to reject tumors in vivo. Although Th1 and Th2 cytokine expression was not affected, we observed differential expression of genes involved in the regulation of an innate immune response. Our results provide evidence that the anti-tumor response can be identified by the \"gene profile\" of T cells. Genomic scale analysis offers the opportunity to identify subtle changes in gene expression in T cells reflecting a distinct biological behavior in vivo.

Recent studies suggest that lysophosphatidic acid (LPA) and its G protein-coupled receptors (GPCRs) LPA(1), LPA(2), or LPA(3) may play a role in the development of several types of cancers, including colorectal cancer. However, the specific receptor subtype(s) and their signal-transduction pathways responsible for LPA-induced cancer cell proliferation have not been fully elucidated. We show by specific RNA interference (RNAi) that LPA(2) and LPA(3) but not LPA(1) are targets for LPA-induced proliferation of HCT116 and LS174T colon cancer cells. We determined that LPA-induced colon cancer cell proliferation requires the beta-catenin signaling pathway, because knockdown of beta-catenin by RNAi abolished LPA-induced proliferation of HCT116 cells. Moreover, LPA activates the main signaling events in the beta-catenin pathway: phosphorylation of glycogen synthase kinase 3beta (GSK3beta), nuclear translocation of beta-catenin, transcriptional activation of T cell factor (Tcf)/lymphoid-enhancer factor (Lef), and expression of target genes. Inhibition of conventional protein kinase C (cPKC) blocked the effects, suggesting its involvement in LPA-induced activation of the beta-catenin pathway. Thus, LPA(2) and LPA(3) signal the proliferation of colon cancer cells through cPKC-mediated activation of the beta-catenin pathway. These results link LPA and its GPCRs to cancer through a major oncogenic signaling pathway.