Search

Background and Purpose: Bifunctional small molecule degraders, which link the target protein with E3 ubiquitin ligase, could lead to the efficient degradation of the target protein. BGB‐16673 is a Bruton's tyrosine kinase (BTK) degrader. A translational PK/PD modelling approach was used to predict the human BTK degradation of BGB‐16673 from preclinical in vitro and in vivo data. Experimental Approach: A simplified mechanistic PK/PD model was used to establish the correlation between the in vitro and in vivo BTK degradation by BGB‐16673 in a mouse model. Human and mouse species differences were compared using the parameters generated from in vitro human or mouse blood, and human or mouse serum spiked TMD‐8 cells. Human PD was then predicted using the simplified mechanistic PK/PD model. Key Results: BGB‐16673 showed potent BTK degradation in mouse whole blood, human whole blood, and TMD‐8 tumour cells in vitro. Furthermore, BGB‐16673 showed BTK degradation in a murine TMD‐8 xenograft model in vivo. The PK/PD model predicted human PD and the observed BTK degradation in clinical studies both showed robust BTK degradation in blood and tumour at clinical dose range. Conclusion and Implications: The presented simplified mechanistic model with reduced number of model parameters is practically easier to be applied to research projects compared with the full mechanistic model. It can be used as a tool to better understand the PK/PD behaviour for targeted protein degraders and increase the confidence when moving to the clinical stage. [ABSTRACT FROM AUTHOR]

In the era of precision medicine with increasing amounts of sequenced cancer and non-cancer genomes of different ancestries, we here enumerate the resulting polygenic disease entities. Based on the cell number status, we first identified six fundamental types of polygenic illnesses, five of which are non-cancerous. Like complex, non-tumor disorders, neoplasms normally carry alterations in multiple genes, including in 'Drivers' and 'Passengers'. However, tumors also lack certain genetic alterations/epigenetic changes, recently named 'Goners', which are toxic for the neoplasm and potentially constitute therapeutic targets. Drivers are considered essential for malignant transformation, whereas environmental influences vary considerably among both types of polygenic diseases. For each form, hyper-rare disorders, defined as affecting <1/108 individuals, likely represent the largest number of disease entities. Loss of redundant tumor-suppressor genes exemplifies such a profoundly rare mutational event. For non-tumor, polygenic diseases, pathway-centered taxonomies seem preferable. This classification is not readily feasible in cancer, but the inclusion of Drivers and possibly also of epigenetic changes to the existing nomenclature might serve as initial steps in this direction. Based on the detailed genetic alterations, the number of polygenic diseases is essentially countless, but different forms of nosologies may be used to restrict the number. [ABSTRACT FROM AUTHOR]

Summary: Covalent Bruton's tyrosine kinase‐inhibitors (cBTK‐i) are highly active in MYD88‐mutated (MYD88Mut) Waldenstrom's macroglobulinaemia and suppress nuclear factor kappa‐light‐chain‐enhancer of activated B cells and extracellular signal‐regulated kinases‐1/2 (ERK1/2)‐related signalling. BTKCys481 mutations are associated with cBTK‐i acquired resistance and are accompanied by reactivation of ERK1/2 that promotes inflammatory cytokine secretion and paracrine‐mediated resistance of BTK wild‐type (BTKWT) tumour cells. Pirtobrutinib is a non‐covalent BTK‐inhibitor that binds at non‐BTKCys481 sites. We show that pirtobrutinib blocked p‐ERK1/2, ERK1/2‐driven inflammatory cytokines, and overcame paracrine‐mediated resistance in MYD88Mut lymphoma cells expressing mutated BTKCys481. Our results provide important mechanistic insights for the activity of pirtobrutinib in MYD88Mut lymphomas carrying BTKCys481 mutations. [ABSTRACT FROM AUTHOR]

Background: Bruton's tyrosine kinase (BTK) is an intracellular signaling enzyme that regulates B-lymphocyte and myeloid cell functions. Due to its involvement in both innate and adaptive immune compartments, BTK inhibitors have emerged as a therapeutic option in autoimmune disorders such as multiple sclerosis (MS). Brain-penetrant, small-molecule BTK inhibitors may also address compartmentalized neuroinflammation, which is proposed to underlie MS disease progression. BTK is expressed by microglia, which are the resident innate immune cells of the brain; however, the precise roles of microglial BTK and impact of BTK inhibitors on microglial functions are still being elucidated. Research on the effects of BTK inhibitors has been limited to rodent disease models. This is the first study reporting effects in human microglia. Methods: Here we characterize the pharmacological and functional properties of fenebrutinib, a potent, highly selective, noncovalent, reversible, brain-penetrant BTK inhibitor, in human microglia and complex human brain cell systems, including brain organoids. Results: We find that fenebrutinib blocks the deleterious effects of microglial Fc gamma receptor (FcγR) activation, including cytokine and chemokine release, microglial clustering and neurite damage in diverse human brain cell systems. Gene expression analyses identified pathways linked to inflammation, matrix metalloproteinase production and cholesterol metabolism that were modulated by fenebrutinib treatment. In contrast, fenebrutinib had no significant impact on human microglial pathways linked to Toll-like receptor 4 (TLR4) and NACHT, LRR and PYD domains-containing protein 3 (NLRP3) signaling or myelin phagocytosis. Conclusions: Our study enhances the understanding of BTK functions in human microglial signaling that are relevant to MS pathogenesis and suggests that fenebrutinib could attenuate detrimental microglial activity associated with FcγR activation in people with MS. [ABSTRACT FROM AUTHOR]

The TEC (tyrosine kinase expressed in hepatocellular carcinoma) family kinases, an important class of protein kinases, play key roles in cell signaling and immune regulation. In this review, the association between the pathogenesis of alopecia areata and the structure and regulatory mechanisms of TEC family kinases in normal physiological processes, is explored. Furthermore, the potential clinical applications of TEC kinases and their inhibitors are highlighted by summarizing current insights into their mechanisms of action, clinical applications, and recent advancements in TEC kinase inhibitor research. [ABSTRACT FROM AUTHOR]

Abstract Background Bruton’s tyrosine kinase (BTK) is an intracellular signaling enzyme that regulates B-lymphocyte and myeloid cell functions. Due to its involvement in both innate and adaptive immune compartments, BTK inhibitors have emerged as a therapeutic option in autoimmune disorders such as multiple sclerosis (MS). Brain-penetrant, small-molecule BTK inhibitors may also address compartmentalized neuroinflammation, which is proposed to underlie MS disease progression. BTK is expressed by microglia, which are the resident innate immune cells of the brain; however, the precise roles of microglial BTK and impact of BTK inhibitors on microglial functions are still being elucidated. Research on the effects of BTK inhibitors has been limited to rodent disease models. This is the first study reporting effects in human microglia. Methods Here we characterize the pharmacological and functional properties of fenebrutinib, a potent, highly selective, noncovalent, reversible, brain-penetrant BTK inhibitor, in human microglia and complex human brain cell systems, including brain organoids. Results We find that fenebrutinib blocks the deleterious effects of microglial Fc gamma receptor (FcγR) activation, including cytokine and chemokine release, microglial clustering and neurite damage in diverse human brain cell systems. Gene expression analyses identified pathways linked to inflammation, matrix metalloproteinase production and cholesterol metabolism that were modulated by fenebrutinib treatment. In contrast, fenebrutinib had no significant impact on human microglial pathways linked to Toll-like receptor 4 (TLR4) and NACHT, LRR and PYD domains-containing protein 3 (NLRP3) signaling or myelin phagocytosis. Conclusions Our study enhances the understanding of BTK functions in human microglial signaling that are relevant to MS pathogenesis and suggests that fenebrutinib could attenuate detrimental microglial activity associated with FcγR activation in people with MS.

Purpose of Review: Tyrosine kinase inhibitors (TKIs) are a major backbone of cancer treatments across a range of malignancies. Observed adverse effects of these targeted therapies include a multitude of clinically relevant cardiotoxicities distinct from those of traditional cytotoxic chemotherapies. Over the past decade, TKI cardiotoxicities have gained growing recognition in the field of cardio-oncology. Here, we aim to review clinically relevant cardiotoxicities of TKIs and incorporate relevant preclinical mechanistic data. Recent Findings: Each TKI class and generation within each class have been associated with a unique cardiotoxicity profile. Broadly, documented cardiotoxicities include arrythmia (atrial and ventricular), heart failure, and vascular complications (thrombosis, endothelial dysfunction, hypertension, and atherosclerosis). Recent and progressing basic investigations have begun to unveil mechanistic underpinnings of these toxicities, such as identifying off-target perturbations of specific signaling pathways, but much more work is needed. Summary: Here, we provide a review of the most clinically relevant cardiovascular toxicities to raise awareness when caring for patients on these drugs. TKIs exemplify the complexity in systemic manipulation of fundamental molecular pathways effects. Translational research in cardio-oncology is of paramount importance which can offer not only a way to better monitor (and prevent) known toxicities, but to more broadly understand and define novel molecular pathways relevant to cardiovascular disease. [ABSTRACT FROM AUTHOR]

Abstract Bruton’s tyrosine kinase (BTK), a nonreceptor tyrosine kinase, plays a remarkable role in the transmission and amplification of extracellular signals to intracellular signaling pathways. Various types of cells use the BTK pathway to communicate, including hematopoietic cells particularly B cells and T cells. The BTK pathway plays a role in controlling the proliferation, survival, and functions of B cells as well as other myeloid cells. First, second, and third-generation BTK inhibitors are currently being evaluated for the treatment of immune-mediated diseases in addition to B cell malignancies. In this article, the available evidence on the action mechanisms of BTK inhibitors is reviewed. Then, the most recent data obtained from preclinical studies and ongoing clinical trials for the treatment of autoimmune diseases, such as pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, systemic lupus erythematosus, Sjögren’s disease, rheumatoid arthritis, systemic sclerosis, multiple sclerosis, myasthenia gravis, and inflammatory diseases such as psoriasis, chronic spontaneous urticaria, atopic dermatitis, and asthma are discussed. In addition, adverse effects and complications associated with BTK inhibitors as well as factors predisposing patients to BTK inhibitors complications are discussed.

Abstract Parkinson’s disease (PD) and inflammatory bowel disease (IBD) are chronic diseases affecting the central nervous system and gastrointestinal tract, respectively. Recent research suggests a bidirectional relationship between neurodegeneration in PD and intestinal inflammation in IBD. PD patients may experience gastrointestinal dysfunction over a decade before motor symptom onset, and IBD may increase the risk of developing PD. Despite the “gut-brain axis” concept, the underlying pathophysiological mechanisms of this potential association remain unclear. This study aimed to investigate the biological mechanisms of differentially expressed genes in PD and IBD using bioinformatics tools, providing novel insights into the co-diagnosis and treatment of these diseases. We constructed a gene marker for disease diagnosis and identified five important genes (BTK, NCF2, CRH, FCGR3A and SERPINA3). Through nomogram and decision tree analyses, we found that both the IBD and PD required only the expression levels of BTK and NCF2 for accurate discrimination. Additionally, small molecule drugs RO-90-7501 and MST-312 may be useful for the treatment of both IBD and PD. These findings offer new perspectives on the co-diagnosis and treatment of PD and IBD, and suggest that targeting BTK may be a promising therapeutic strategy for both diseases.

In this review we summarize the current evidence describing the management of patients with relapsed/refractory MCL and outline the various novel therapeutics that have been developed over the past two decades. We also describe how overall response rates, complete response rates, duration of responses, and life expectancy have dramatically increased with the introduction of novel therapies, particularly covalent Bruton Tyrosine Kinase inhibitors (BTKi) and chimeric antigen receptor T-cell (CAR-T) therapy. The most recent emerging options for patients with progressive disease following BTKi or CAR-T, including non-covalent BTKi, antibody-drug conjugates, Bcl-2 inhibitors, and bispecific antibodies, may further improve response rates and outcomes. Future directions should focus on identifying the best sequencing and/or combinations of the increasingly available treatment options while prioritizing strategies with curative potential. [ABSTRACT FROM AUTHOR]

Primary central nervous system lymphoma (PCNSL) is a rare and highly aggressive lymphoma entirely localized in the central nervous system or vitreoretinal space. PCNSL generally initially responds to methotrexate-containing chemotherapy regimens, but progressive or relapsing disease is common, and the prognosis is poor for relapsed or refractory (R/R) patients. PCNSL is often characterized by activation of nuclear factor kappa B (NF-κB) due to mutations in the B-cell receptor (BCR) or toll-like receptor (TLR) pathways, as well as immune evasion. Targeted treatments that inhibit key PCNSL mechanisms and pathways are being evaluated; inhibition of Bruton's tyrosine kinase (BTK) downstream of BCR activation has demonstrated promising results in treating R/R disease. This review will summarize the evidence and potential for targeted therapeutic agents to improve treatment outcomes in PCNSL. This includes immunotherapeutic and immunomodulatory approaches and inhibitors of the key pathways driving PCNSL, such as aberrant BCR and TLR signaling. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shenyang Pharmaceutical University is the property of Shenyang Pharmaceutical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Parkinson's disease (PD) and inflammatory bowel disease (IBD) are chronic diseases affecting the central nervous system and gastrointestinal tract, respectively. Recent research suggests a bidirectional relationship between neurodegeneration in PD and intestinal inflammation in IBD. PD patients may experience gastrointestinal dysfunction over a decade before motor symptom onset, and IBD may increase the risk of developing PD. Despite the "gut-brain axis" concept, the underlying pathophysiological mechanisms of this potential association remain unclear. This study aimed to investigate the biological mechanisms of differentially expressed genes in PD and IBD using bioinformatics tools, providing novel insights into the co-diagnosis and treatment of these diseases. We constructed a gene marker for disease diagnosis and identified five important genes (BTK, NCF2, CRH, FCGR3A and SERPINA3). Through nomogram and decision tree analyses, we found that both the IBD and PD required only the expression levels of BTK and NCF2 for accurate discrimination. Additionally, small molecule drugs RO-90-7501 and MST-312 may be useful for the treatment of both IBD and PD. These findings offer new perspectives on the co-diagnosis and treatment of PD and IBD, and suggest that targeting BTK may be a promising therapeutic strategy for both diseases. [ABSTRACT FROM AUTHOR]

Bruton's tyrosine kinase (BTK), a non-receptor tyrosine kinase crucial for B cell development and function, acts downstream of the B cell receptor (BCR) in the BCR pathway. Other kinases involved downstream of the BCR besides BTK such as Syk, Lyn, PI3K, and Mitogen-activated protein (MAP) kinases also play roles in relaying signals from the BCR to provide pro-survival, activation, and proliferation cues. BTK signaling is implicated in various B-cell lymphomas such as mantle cell lymphoma, Waldenström Macroglobulinemia, follicular lymphoma, and diffuse large B cell lymphoma, leading to the development of transformative treatments like ibrutinib, the first-in-class covalent BTK inhibitor, and pirtobrutinib, the first-in-class noncovalent BTK inhibitor. However, kinase-deficient mutations C481F, C481Y, C481R, and L528W in the BTK gene confer resistance to both covalent and non-covalent BTK inhibitors, facilitating B cell survival and lymphomagenesis despite kinase inactivation. Further studies have revealed BTK's non-catalytic scaffolding function, mediating the assembly and activation of proteins including Toll-like receptor 9 (TLR9), vascular cell adhesion protein 1 (VCAM-1), hematopoietic cell kinase (HCK), and integrin-linked kinase (ILK). This non-enzymatic role promotes cell survival and proliferation independently of kinase activity. Understanding BTK's dual roles unveils opportunities for therapeutics targeting its scaffolding function, promising advancements in disrupting lymphomagenesis and refining B cell lymphoma treatments. [ABSTRACT FROM AUTHOR]

Bruton's tyrosine kinase (BTK) inhibitors have revolutionized the treatment of B‐cell malignancies. They target BTK, a key effector in the B‐cell receptor (BCR) signaling pathway, crucial for B‐cell survival and proliferation. The first‐in‐class irreversible BTK inhibitor, ibrutinib, was approved for various B‐cell malignancies but has limitations due to off‐target effects. Second‐generation inhibitors, such as acalabrutinib and zanubrutinib, offer improved selectivity and reduced side effects. However, resistance to BTK inhibitors, driven by BTK mutations, remains a challenge. Combinatorial therapies with PI3K inhibitors, immune checkpoint inhibitors, BH3 mimetics, and anti‐CD20 antibodies show promise in overcoming resistance. Noncovalent BTK inhibitors and proteolysis‐targeting chimeras (PROTACs) are emerging strategies with potential to combat resistance. Overall, advancements in BTK‐targeted therapies provide hope for improved outcomes in patients with B‐cell malignancies and a promising avenue to address drug resistance. Further research is needed to optimize combination therapies and identify optimal treatment regimens. [ABSTRACT FROM AUTHOR]

BP001 is a promising small molecule compound that has been specifically designed to target and degrade Bruton's tyrosine kinases (BTK), which is known to play a crucial role in lymphoma development. Macrophages are important immune cells in inflammation regulation and immune response. In this study, we aimed to investigate the effect of BP001 on RAW264.7 macrophage activation stimulated by a high glucose environment. Our findings revealed that treatment with BP001 significantly inhibited the production of nitric oxide (NO), reactive oxygen species (ROS), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) in RAW264.7 macrophages exposed to high glucose conditions. Furthermore, we observed that BP001 treatment also down-regulated the expression of BTK in these activated macrophages. To elucidate the underlying mechanism behind these observations, we investigated the phosphorylation level of NF-κB. Our results demonstrated that BP001 treatment led to decreased phosphorylation levels of NF-κB, thereby inhibiting the level of inflammation. In addition, we also found that BP001 could restore RAW264.7 macrophages from the pro-inflammatory state to the normal phenotype and reduce the occurrence of inflammation. The regulatory function of BP001 in autoimmunity is mediated through the degradation of BTK protein, thereby attenuating macrophage activation. Additionally, BTK plays a pivotal role in transcriptional regulation by inducing NF-κB activity. Consequently, it is not difficult to understand that BP001 effectively inhibits inflammation. In conclusion, the present study provides evidence that BP001, a BTK degrader, can serve as a novel immunomodulator of inflammation induced by high glucose, making it an attractive candidate for further investigation. [ABSTRACT FROM AUTHOR]

Evobrutinib is a second‐generation, highly selective, irreversible Bruton's tyrosine kinase (BTK) inhibitor that has shown efficacy in the autoimmune diseases arthritis and multiple sclerosis. Its development as a positron emission tomography (PET) radiotracer has potential for in vivo imaging of BTK in various disease models including several cancers, severe acute respiratory syndrome‐coronavirus‐2 (SARS‐CoV‐2), and lipopolysaccharide (LPS)‐induced lung damage. Herein, we report the automated radiosynthesis of [11C]evobrutinib using a base‐aided palladium‐NiXantphos‐mediated 11C‐carbonylation reaction. [11C]Evobrutinib was reliably formulated in radiochemical yields of 5.5 ± 1.5% and a molar activity of 34.5 ± 17.3 GBq/μmol (n = 12) with 99% radiochemical purity. Ex vivo autoradiography studies showed high specific binding of [11C]evobrutinib in HT‐29 colorectal cancer mouse xenograft tissues (51.1 ± 7.1%). However, in vivo PET/computed tomography (CT) imaging with [11C]evobrutinib showed minimal visualization of HT‐29 colorectal cancer xenografts and only a slight increase in radioactivity accumulation in the associated time‐activity curves. In preliminary PET/CT studies, [11C]evobrutinib failed to visualize either SARS‐CoV‐2 pseudovirus infection or LPS‐induced injury in mouse models. In conclusion, [11C]evobrutinib was successfully synthesized by 11C‐carbonylation and based on our preliminary studies does not appear to be a promising BTK‐targeted PET radiotracer in the rodent disease models studied herein. [ABSTRACT FROM AUTHOR]

Background: Bones undergo a constant remodeling, a process involving osteoclast‐mediated bone resorption and osteoblast‐mediated bone formation, crucial for maintaining healthy bone mass. We previously observed that miR‐185 depletion may promote bone formation by regulating Bgn expression and the BMP/Smad signaling pathway. However, the effects of miR‐185‐5p on the osteoclasts and bone remodeling have not been elucidated, warranting further exploration. Methods: Tartrate‐resistant acid phosphatase staining was utilized to assess the differentiation ability of bone marrow mononuclear macrophages (BMMs) from mmu‐miR‐185 gene knockout (KO) mice and wild‐type (WT) mice. A reverse transcriptase‐quantitative PCR was conducted to compare differences in miR‐185‐5p and osteoclast marker molecules, including Trap, Dcstamp, Ctsk and Nfatc1, between the KO group and WT group BMMs. Western blot analysis was employed to observe the expression of osteoclast marker molecules. A cell‐counting kit‐8 was used to analyze cell proliferation ability. Transwell experiments were conducted to detect cell migration. Dual‐luciferase reporter assays were employed to confirm whether Btk is a downstream target gene of miR‐185‐5p. Results: miR‐185 depletion promoted osteoclast differentiation in bone marrow‐derived monocytes/macrophages. Overexpression of miR‐185‐5p in RAW264.7 cells inhibited differentiation and migration of osteoclasts. Furthermore, Btk was identified as a downstream target gene of miR‐185‐5p, suggesting that miR‐185‐5p may inhibit osteoclast differentiation and migration by targeting Btk. Conclusions: miR‐185 regulates osteoclasts differentiation, with overexpression of miR‐185‐5p inhibiting osteoclast differentiation and migration in vitro. Additionally, miR‐185‐5p may modulate osteoclastic differentiation and migration by regulating Btk expression. [ABSTRACT FROM AUTHOR]

Ibrutinib, a tyrosine kinase inhibitor with a broad spectrum of action, has been successfully explored to treat hematological and solid cancers. Herein, we investigated the anti-cancer effect of Ibrutinib on melanoma cell lines. Cytotoxicity was evaluated using the MTT assay. Apoptosis, mitochondrial membrane potential, reactive oxygen species (ROS) production, cell proliferation, and cell cycle stages were determined by flow cytometry. LDH release and Caspase 3/7 activity were determined by colorimetric and luminescent assays, respectively. Cell migration was evaluated by wound scratch assay. Gene expression was determined by real-time PCR. Gene Ontology (GO) enrichment analysis of melanoma clinical samples was performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID). MTT assays showed that Ibrutinib is toxic for MeWo, SK-MEL-28, and WM164 cells. The annexin V/PI staining, Caspase 3/7 activity, and LDH release in MeWo cells revealed that apoptosis is the primary mechanism of death caused by Ibrutinib. Corroborating such observation, we identified that Ibrutinib treatment impairs the mitochondrial membrane potential of such cells and significantly increases the transcriptional levels of the pro-apoptotic factors ATM, HRK, BAX, BAK, CASP3, and CASP8. Furthermore, Ibrutinib showed antimetastatic potential by inhibiting the migration of MeWo cells. Finally, we performed a functional enrichment analysis and identified that the differential expression of Ibrutinib-target molecules is associated with enrichment of apoptosis and necrosis pathways in melanoma samples. Taken together, our results clearly suggest that Ibrutinib can be successfully explored as an effective therapeutic approach for melanomas. [ABSTRACT FROM AUTHOR]

Simple Summary: Chronic Lymphocytic Leukemia (CLL) is one of the most frequent leukemia in the west countries for adult patients. It's typically a slow-growing disease and the majority of patients do not need immediate treatment at diagnosis. Advanced stages or symptomatic disease require therapy. The treatment landscape of CLL has changed considerably in the last decades with the introduction of new targeted agents leading to improved outcome for patients with CLL compared to standard chemo-immunotherapy, especially for those with high-risk features, as del17p13, TP53 mutations and unmutated immunoglobulin heavy chain (IGHV) genes. In this narrative review, we comprehensively summarized and discussed all the new approaches currently investigated in completed and on-going clinical trials, both with single new agents and in combination strategies to pursuing not only a disease control but the eradication of the leukemic clone. In the last few years, several agents targeting molecules that sustain the survival and the proliferation of chronic lymphocytic leukemia (CLL) cells have become clinically available. Most of these drugs target surface proteins, such as CD19 or CD20, via monoclonal or bispecific monoclonal antibodies (BsAbs), CAR T cells, intracellular proteins like BTK by using covalent or non-covalent inhibitors or BCL2 with first or second generation BH3-mimetics. Since the management of CLL is evolving quickly, in this review we highlighted the most important innovative treatments including novel double and triple combination therapies, CAR T cells and BsAbs for CLL. Recently, a large number of studies on novel combinations and newer strategic options for CLL therapy have been published or presented at international conferences, which were summarized and linked together. Although the management of treatment with a single continuous agent is easier, the emergence of protein mutations, long-term toxicities and costs are important concerns that favor the use of a fixed duration therapy. In the future, a measurable residual disease (MRD)-guided treatment cessation and MRD-based re-initiation of targeted therapy seems to be a more feasible approach, allowing identification of the patients who might benefit from continuous therapy or who might need a consolidation with BsAbs or CAR T cells to clear the neoplastic clone. [ABSTRACT FROM AUTHOR]

Environmental microorganisms have a complex, dynamic relationship with flora and fauna, with consequences for the host organism that range from immunogenic to immunoprotective. The pathogenic chytrid fungus, Batrachochytrium dendrobatidis (Bd), can infect the skin of amphibians and may lead to the deadly disease, Chytridiomycosis. Some skin-associated microorganisms of amphibians have the potential to prevent or mitigate Bd infection by producing anti-fungal metabolites. Yet, the majority of environmentally derived bacteria that may inhabit amphibian skin have not been investigated for their interaction with Bd. The soil-dwelling bacteria, Bacillus thuringiensis (Bt), is a ubiquitous species that is widely applied as a natural insecticide and produces anti-fungal metabolites as a byproduct of metabolism. With the increased use of Bt-based insecticides and the potential benefit of antifungal properties, we investigated the effects of Bt against Bd. This study investigates (1) the impact of Bt volatile metabolites on the growth of Bd and (2) the impact of autoclaved Bt products on the growth of Bd in vitro. Our findings showed growth inhibition of Bd (p < 0.001) by Bt volatile organic compounds (VOC) when cultured in split petri plates, relative to the control. Yet, in a liquid culture of Bd, autoclaved secondary metabolites from Bt demonstrated a significant increase in Bd growth (p < 2.2e-16). Together these results suggest that Bt may produce metabolites that beneficially inhibit Bd in some conditions while negatively enhancing the growth of the Bd in others.

Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasia that lacks effective targeted chemotherapies. Clinically, JMML manifests as monocytic leukocytosis, splenomegaly with consequential thrombocytopenia. Most commonly, patients have gain-of-function (GOF) oncogenic mutations in PTPN11 (SHP2), leading to Erk and Akt hyperactivation. Mechanism(s) involved in co-regulation of Erk and Akt in the context of GOF SHP2 are poorly understood. Here, we show that Bruton's tyrosine kinase (BTK) is hyperphosphorylated in GOF Shp2-bearing cells and utilizes B cell adaptor for PI3K to cooperate with p110δ, the catalytic subunit of PI3K. Dual inhibition of BTK and p110δ reduces the activation of both Erk and Akt. In vivo, individual targeting of BTK or p110δ in a mouse model of human JMML equally reduces monocytosis and splenomegaly; however, the combined treatment results in a more robust inhibition and uniquely rescues anemia and thrombocytopenia. RNA-seq analysis of drug-treated mice showed a profound reduction in the expression of genes associated with leukemic cell migration and inflammation, leading to correction in the infiltration of leukemic cells in the lung, liver, and spleen. Remarkably, in a patient derived xenograft model of JMML, leukemia-initiating stem and progenitor cells were potently inhibited in response to the dual drug treatment.

B cell antigen receptor (BCR) signaling is a key driver of growth and survival in both normal and malignant B cells. Several lines of evidence support an important pathogenic role of the BCR in chronic lymphocytic leukemia (CLL). The significant improvement of CLL patients' survival with the use of various BCR pathway targeting inhibitors, supports a crucial involvement of BCR signaling in the pathogenesis of CLL. Although the treatment landscape of CLL has significantly evolved in recent years, no agent has clearly demonstrated efficacy in patients with treatment-refractory CLL in the long run. To identify new drug targets and mechanisms of drug action in neoplastic B cells, a detailed understanding of the molecular mechanisms of leukemic transformation as well as CLL cell survival is required. In the last decades, studies of genetically modified CLL mouse models in line with CLL patient studies provided a variety of exciting data about BCR and BCR-associated kinases in their role in CLL pathogenesis as well as disease progression. BCR surface expression was identified as a particularly important factor regulating CLL cell survival. Also, BCR-associated kinases were shown to provide a crosstalk of the CLL cells with their tumor microenvironment, which highlights the significance of the cells' milieu in the assessment of disease progression and treatment. In this review, we summarize the major findings of recent CLL mouse as well as patient studies in regard to the BCR signalosome and discuss its relevance in the clinics. [ABSTRACT FROM AUTHOR]

Marginal zone lymphoma are a heterogeneous group of indolent B-cell malignancies where the B-cell receptor (BCR) signaling pathway plays a central role in the proliferation and survival of malignant cells. Targeting the BCR and its downstream kinases such as Bruton tyrosine kinase (BTK) is critical for the control and the inhibition of the cells survival. First-line treatments relie upon standard approaches with monoclonal antibodies alone or in association with chemotherapy. Second-line treatments have evolved these late years with the outbreak of oral BTK inhibitors. Ibrutinib is the first-in class small-molecule with proven and sustained efficacy. Second-generation and highly effective BTK inhibitors like Zanubrutinib or Acalabrutinib are changing the MZL therapeutic landscape with more deeply and prolonged responses as well as a more favorable toxicity profile. [ABSTRACT FROM AUTHOR]

Ritlecitinib is a small molecule in clinical development that covalently and irreversibly inhibits Janus kinase 3 (JAK3) and the TEC family of kinases (BTK, BMX, ITK, TXK, and TEC). This phase 1, open‐label, parallel‐group study assessed target occupancy and functional effects of ritlecitinib on JAK3 and TEC family kinases in healthy participants aged 18‐60 years who received 50 or 200 mg single doses of ritlecitinib on day 1. Blood samples to assess ritlecitinib pharmacokinetics, target occupancy, and pharmacodynamics were collected over 48 hours. Target occupancy was assessed using mass spectroscopy. Functional inhibition of JAK3‐dependent signaling was measured by the inhibition of the phosphorylation of its downstream target signal transducer and activator of transcription 5 (pSTAT5), following activation by interleukin 15 (IL‐15). The functional inhibition of Bruton's tyrosine kinase (BTK)‐dependent signaling was measured by the reduction in the upregulation of cluster of differentiation 69 (CD69), an early marker of B‐cell activation, following treatment with anti‐immunoglobulin D. Eight participants received one 50 mg ritlecitinib dose and 8 participants received one 200 mg dose. Ritlecitinib plasma exposure increased in an approximately dose‐proportional manner from 50 to 200 mg. The maximal median JAK3 target occupancy was 72% for 50 mg and 64% for 200 mg. Ritlecitinib 50 mg had >94% maximal target occupancy of all TEC kinases, except BMX (87%), and 200 mg had >97% for all TEC kinases. For BTK and TEC, ritlecitinib maintained high target occupancy throughout a period of 48 hours. Ritlecitinib reduced pSTAT5 levels following IL‐15‐ and BTK‐dependent signaling in a dose‐dependent manner. These target occupancy and functional assays demonstrate the dual inhibition of the JAK3‐ and BTK‐dependent pathways by ritlecitinib. Further studies are needed to understand the contribution to clinical effects of inhibiting these pathways. [ABSTRACT FROM AUTHOR]

B-cell receptor (BCR) is a B cell hallmark surface complex regulating multiple cellular processes in normal as well as malignant B cells. Igα (CD79a)/Igβ (CD79b) are essential components of BCR that are indispensable for its functionality, signal initiation, and signal transduction. CD79a/CD79b-mediated BCR signaling is required for the survival of normal as well as malignant B cells via a wide signaling network. Recent studies identified the great complexity of this signaling network and revealed the emerging role of CD79a/CD79b in signal integration. In this review, we have focused on functional features of CD79a/CD79b, summarized signaling consequences of CD79a/CD79b post-translational modifications, and highlighted specifics of CD79a/CD79b interactions within BCR and related signaling cascades. We have reviewed the complex role of CD79a/CD79b in multiple aspects of normal B cell biology and how is the normal BCR signaling affected by lymphoid neoplasms associated CD79A/CD79B mutations. We have also summarized important unresolved questions and highlighted issues that remain to be explored for better understanding of CD79a/CD79b-mediated signal transduction and the eventual identification of additional therapeutically targetable BCR signaling vulnerabilities. [ABSTRACT FROM AUTHOR]

Background: B-cell receptor (BCR) signaling is crucial for normal B-cell development and adaptive immunity. In chronic lymphocytic leukemia (CLL), the malignant B cells display many features of normal mature B lymphocytes, including the expression of functional B-cell receptors (BCRs). Cross talk between CLL cells and the microenvironment in secondary lymphatic organs results in BCR signaling and BCR-driven proliferation of the CLL cells. This critical pathomechanism can be targeted by blocking BCR-related kinases (BTK, PI3K, spleen tyrosine kinase) using small-molecule inhibitors. Among these targets, Bruton tyrosine kinase (BTK) inhibitors have the highest therapeutic efficacy; they effectively block leukemia cell proliferation and generally induce durable remissions in CLL patients, even in patients with high-risk disease. By disrupting tissue homing receptor (i.e., chemokine receptor and adhesion molecule) signaling, these kinase inhibitors also mobilize CLL cells from the lymphatic tissues into the peripheral blood (PB), causing a transient redistribution lymphocytosis, thereby depriving CLL cells from nurturing factors within the tissue niches. Summary: The clinical success of the BTK inhibitors in CLL underscores the central importance of the BCR in CLL pathogenesis. Here, we review CLL pathogenesis with a focus on the role of the BCR and other microenvironment cues. Key Messages: (i) CLL cells rely on signals from their microenvironment for proliferation and survival. (ii) These signals are mediated by the BCR as well as chemokine and integrin receptors and their respective ligands. (iii) Targeting the CLL/microenvironment interaction with small-molecule inhibitors provides a highly effective treatment strategy, even in high-risk patients. [ABSTRACT FROM AUTHOR]

Abstract Background Bruton’s tyrosine kinase (Btk) is an enzyme expressed in leukocytes other than T lymphocytes and plasma cells and involved in B-cell receptor- and Fcγ receptor (FcγR)-mediated signal transduction. Btk inhibitors potentially suppress autoantibody production due to the expected inhibitory ability of B lymphocyte differentiation into antibody-producing plasma cells and reduce FcγR-mediated neutrophil activation, including the release of neutrophil extracellular traps (NETs). Microscopic polyangiitis (MPA) is a systemic small-vessel vasculitis characterized by the pathogenic autoantibody, antineutrophil cytoplasmic antibody (ANCA) that reacts with myeloperoxidase (MPO). MPO and MPO-ANCA immune complex (IC)-induced FcγR-mediated NETs are critically involved in MPA pathogenesis. This study aimed to demonstrate the therapeutic efficacy of the Btk inhibitor tirabrutinib on MPA. Methods Various doses of tirabrutinib or vehicle were orally administered to Sprague–Dawley rats daily. Four weeks later, the number of peripheral B lymphocytes was counted, and Btk phosphorylation in B lymphocytes was evaluated by flow cytometry. Human peripheral blood neutrophils were stimulated by MPO and anti-MPO antibody ICs (MPO and anti-MPO-ICs), and Btk and its downstream Vav phosphorylation were assessed by western blotting. The effects of tirabrutinib on MPO and anti-MPO-IC-induced NET formation were examined in vitro. Wistar Kyoto rats were immunized with human MPO to induce experimental MPA and given drug-free or tirabrutinib-containing feed (0.0037% or 0.012%) from day 0 or 28. All rats were euthanized on day 42 for serological and histological evaluation. Results Tirabrutinib inhibited Btk phosphorylation without decreasing B lymphocytes in vivo. Neutrophil Btk and Vav were phosphorylated when stimulated with MPO and anti-MPO-ICs. Tirabrutinib suppressed MPO and anti-MPO-IC-induced NET formation in vitro and ameliorated experimental MPA in a dose-dependent manner in vivo. Although MPO-ANCA production was not affected, NET-forming neutrophils in the blood were significantly reduced by tirabrutinib. Conclusions The Btk inhibitor tirabrutinib suppressed MPO and anti-MPO-IC-induced NET formation in vitro and ameliorated experimental MPA by reducing NET-forming neutrophils but not decreasing MPO-ANCA titer in vivo. This study suggests that Btk is a possible therapeutic target in MPA.

Brutons tyrosine kinase (BTK) is a critical downstream signaling element from the B-cell receptor (BCR) that has been effectively inhibited in B-cell cancers by irreversible, covalent inhibitors including ibrutinib and acalabrutinib. All FDA-approved covalent BTK inhibitors rely on binding to the cysteine 481 (C481) amino acid within the active site of BTK, thus rendering it inert. While covalent BTK inhibitors have been very successful in multiple B-cell malignancies, improving both overall survival and progression-free survival relative to chemoimmunotherapy in phase 3 trials, they can be limited by intolerance and disease progression. Pirtobrutinib is a novel, highly selective, and non-covalent BTK inhibitor that binds independently of C481, and in a recent, first-in-human phase 1/2 clinical trial was shown to be extremely well tolerated and lead to remissions in relapsed/refractory patients with multiple B-cell malignancies. Here, we review the pharmacologic rationale for pursuing non-covalent BTK inhibitors, the clinical need for such inhibitors, existing safety, and resistance mechanism data for pirtobrutinib, and the forthcoming clinical trials that seek to define the clinical utility of pirtobrutinib, which has the potential to fulfill multiple areas of unmet clinical need for patients with B-cell malignancies.

Abstract Background Bruton’s tyrosine kinase (BTK) is a key signaling node in B cell receptor (BCR) and Fc receptor (FcR) signaling. BTK inhibitors (BTKi) are an emerging oral treatment option for patients suffering from multiple sclerosis (MS). Remibrutinib (LOU064) is a potent, highly selective covalent BTKi with a promising preclinical and clinical profile for MS and other autoimmune or autoallergic indications. Methods The efficacy and mechanism of action of remibrutinib was assessed in two different experimental autoimmune encephalomyelitis (EAE) mouse models for MS. The impact of remibrutinib on B cell-driven EAE pathology was determined after immunization with human myelin oligodendrocyte glycoprotein (HuMOG). The efficacy on myeloid cell and microglia driven neuroinflammation was determined in the RatMOG EAE. In addition, we assessed the relationship of efficacy to BTK occupancy in tissue, ex vivo T cell response, as well as single cell RNA-sequencing (scRNA-seq) in brain and spinal cord tissue. Results Remibrutinib inhibited B cell-dependent HuMOG EAE in dose-dependent manner and strongly reduced neurological symptoms. At the efficacious oral dose of 30 mg/kg, remibrutinib showed strong BTK occupancy in the peripheral immune organs and in the brain of EAE mice. Ex vivo MOG-specific T cell recall response was reduced, but not polyclonal T cell response, indicating absence of non-specific T cell inhibition. Remibrutinib also inhibited RatMOG EAE, suggesting that myeloid cell and microglia inhibition contribute to its efficacy in EAE. Remibrutinib did not reduce B cells, total Ig levels nor MOG-specific antibody response. In brain and spinal cord tissue a clear anti-inflammatory effect in microglia was detected by scRNA-seq. Finally, remibrutinib showed potent inhibition of in vitro immune complex-driven inflammatory response in human microglia. Conclusion Remibrutinib inhibited EAE models by a two-pronged mechanism based on inhibition of pathogenic B cell autoreactivity, as well as direct anti-inflammatory effects in microglia. Remibrutinib showed efficacy in both models in absence of direct B cell depletion, broad T cell inhibition or reduction of total Ig levels. These findings support the view that remibrutinib may represent a novel treatment option for patients with MS.

Mast cells are activated through a variety of different receptors to release preformed granules and mediators synthesized de novo. However, the physiology and function of mast cells are not fully understood. Traditional studies of mast cell activation in humans have utilized cultures of tissue-derived mast cells including CD34+ progenitor cells or well-characterized commercially available cell lines. One limitation of these methods is that mast cells are no longer in a natural state. Therefore, their applicability to human skin disorders may be limited. Human skin explant models have been utilized to investigate the short-term effects of cell mediators, drugs, and irritants on skin while avoiding the ethical concerns surrounding in vivo stimulation studies with non-approved agents. Nonetheless, few studies have utilized intact human tissue to study mast cell degranulation. This “Methods” paper describes the development and application of an intact skin explant model to study human mast cell activation. In this manuscript, we share our protocol for setting up ex vivo human skin explants and describe the results of stimulation experiments and techniques to minimize trauma-induced histamine release. Skin explants were generated using de-identified, full-thickness, non-diseased skin specimens from plastic and reconstructive surgeries. Results were reproducible and demonstrated FcɛRI- and MRGPRX2-induced mediator release which was inhibited with the use of a BTK inhibitor and QWF, respectively. Thus, this explant model provides a quick and accessible method of assessing human skin mast cell activation and inhibition.

Full-length Bruton’s tyrosine kinase (BTK) has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3–SH2–kinase core. Precisely how the BTK N-terminal domains (the Pleckstrin homology/Tec homology [PHTH] domain and proline-rich regions [PRR] contain linker) contribute to BTK regulation remains unclear. We have produced crystals of full-length BTK for the first time but despite efforts to stabilize the autoinhibited state, the diffraction data still reveal only the SH3–SH2–kinase core with no electron density visible for the PHTH–PRR segment. Cryo-electron microscopy (cryoEM) data of full-length BTK, on the other hand, provide the first view of the PHTH domain within full-length BTK. CryoEM reconstructions support conformational heterogeneity in the PHTH–PRR region wherein the globular PHTH domain adopts a range of states arrayed around the autoinhibited SH3–SH2–kinase core. On the way to activation, disassembly of the SH3–SH2–kinase core opens a new autoinhibitory site on the kinase domain for PHTH domain binding that is ultimately released upon interaction of PHTH with phosphatidylinositol (3,4,5)-trisphosphate. Membrane-induced dimerization activates BTK and we present here a crystal structure of an activation loop swapped BTK kinase domain dimer that likely represents the conformational state leading to trans-autophosphorylation. Together, these data provide the first structural elucidation of full-length BTK and allow a deeper understanding of allosteric control over the BTK kinase domain during distinct stages of activation.

Bruton tyrosine kinase (BTK) is an essential enzyme in the signaling pathway of the B-cell receptor (BCR) and is vital for the growth and activation of B-cells. Dysfunction of BTK has been linked to different types of B-cell cancers, autoimmune conditions, and inflammatory ailments. Therefore, focusing on BTK has become a hopeful approach in the field of therapeutics. Small-molecule inhibitors of BTK have been developed to selectively inhibit its activity and disrupt B-cell signaling pathways. These inhibitors bind to the active site of BTK and prevent its phosphorylation, leading to the inhibition of downstream signaling cascades. Regulatory authorities have granted approval to treat B-cell malignancies, such as chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), with multiple small-molecule BTK inhibitors. This review offers a comprehensive analysis of the synthesis and clinical application of conventional small-molecule BTK inhibitors at various clinical stages, as well as presents promising prospects for the advancement of new small-molecule BTK inhibitors. [ABSTRACT FROM AUTHOR]

In the microenvironment, cell interactions are established between different cell types to regulate their migration, survival and activation. β-Catenin is a multifunctional protein that stabilizes cell–cell interactions and regulates cell survival through its transcriptional activity. We used chronic lymphocytic leukemia (CLL) cells as a cellular model to study the role of β-catenin in regulating the adhesion of tumor cells to their microenvironment, which is necessary for tumor cell survival and accumulation. When co-cultured with a stromal cell line (HS-5), a fraction of the CLL cells adhere to stromal cells in a dynamic fashion regulated by the different levels of β-catenin expression. In non-adherent cells, β-catenin is stabilized in the cytosol and translocates into the nucleus, increasing the expression of cyclin D1. In adherent cells, the level of cytosolic β-catenin is low but membrane β-catenin helps to stabilize the adhesion of CLL to stromal cells. Indeed, the overexpression of β-catenin enhances the interaction of CLL with HS-5 cells, suggesting that this protein behaves as a regulator of cell adhesion to the stromal component and of the transcriptional regulation of cell survival. Inhibitors that block the stabilization of β-catenin alter this equilibrium and effectively disrupt the support that CLL cells receive from the cross-talk with the stroma. [ABSTRACT FROM AUTHOR]

Copyright of Istanbul Commerce University Journal of Social Sciences / İstanbul Ticaret Üniversitesi Sosyal Bilimler Dergisi is the property of Istanbul Commerce University Journal of Social Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Myeloid-derived suppressor cells (MDSC) have been linked to loss of immune effector cell function through a variety of mechanisms such as the generation of reactive oxygen and nitrogen species and the production of inhibitory cytokines. Our group has shown that signaling through Bruton's tyrosine kinase (BTK) is important for MDSC function. Ibrutinib is an orally administered targeted agent that inhibits BTK activation and is currently used for the treatment of B cell malignancies. Using a syngeneic murine model of melanoma, the effect of BTK inhibition with ibrutinib on the therapeutic response to systemic PD-L1 blockade was studied. BTK was expressed by murine MDSC and their activation was inhibited by ibrutinib. Ibrutinib was not directly cytotoxic to cancer cells in vitro, but it inhibited BTK activation in MDSC and reduced expression of inducible nitric oxide synthase (NOS2) and production of nitric oxide. Ibrutinib treatments decreased the levels of circulating MDSC in vivo and increased the therapeutic efficacy of anti-PD-L1 antibody treatment. Gene expression profiling showed that ibrutinib decreased Cybb (NOX2) signaling, and increased IL-17 signaling (upregulating downstream targets Mmp9, Ptgs2, and S100a8). These results suggest that further exploration of MDSC inhibition could enhance the immunotherapy of advanced melanoma. Précis Inhibition of Bruton's tyrosine kinase, a key enzyme in myeloid cellular function, improves therapeutic response to an anti-PD-L1 antibody in an otherwise fairly resistant murine melanoma model. [ABSTRACT FROM AUTHOR]

The drug development process suffers from low success rates and requires expensive and time-consuming procedures. The traditional one drug–one target paradigm is often inadequate to treat multifactorial diseases. Multitarget drugs may potentially address problems such as adverse reactions to drugs. With the aim to discover a multitarget potential inhibitor for B-cell lymphoma treatment, herein, we developed a general pipeline combining machine learning, the interpretable model SHapley Additive exPlanation (SHAP), and molecular dynamics simulations to predict active compounds and fragments. Bruton's tyrosine kinase (BTK) and Janus kinase 3 (JAK3) are popular synergistic targets for B-cell lymphoma. We used this pipeline approach to identify prospective potential dual inhibitors from a natural product database and screened three candidate inhibitors with acceptable drug absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. Ultimately, the compound CNP0266747 with specialized binding conformations that exhibited potential binding free energy against BTK and JAK3 was selected as the optimum choice. Furthermore, we also identified key residues and fingerprint features of this dual-target inhibitor of BTK and JAK3. [ABSTRACT FROM AUTHOR]

Ibrutinib, a tyrosine kinase inhibitor with a broad spectrum of action, has been successfully explored to treat hematological and solid cancers. Herein, we investigated the anti-cancer effect of Ibrutinib on melanoma cell lines. Cytotoxicity was evaluated using the MTT assay. Apoptosis, mitochondrial membrane potential, reactive oxygen species (ROS) production, cell proliferation, and cell cycle stages were determined by flow cytometry. LDH release and Caspase 3/7 activity were determined by colorimetric and luminescent assays, respectively. Cell migration was evaluated by wound scratch assay. Gene expression was determined by real-time PCR. Gene Ontology (GO) enrichment analysis of melanoma clinical samples was performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID). MTT assays showed that Ibrutinib is toxic for MeWo, SK-MEL-28, and WM164 cells. The annexin V/PI staining, Caspase 3/7 activity, and LDH release in MeWo cells revealed that apoptosis is the primary mechanism of death caused by Ibrutinib. Corroborating such observation, we identified that Ibrutinib treatment impairs the mitochondrial membrane potential of such cells and significantly increases the transcriptional levels of the pro-apoptotic factors ATM, HRK, BAX, BAK, CASP3, and CASP8. Furthermore, Ibrutinib showed antimetastatic potential by inhibiting the migration of MeWo cells. Finally, we performed a functional enrichment analysis and identified that the differential expression of Ibrutinib-target molecules is associated with enrichment of apoptosis and necrosis pathways in melanoma samples. Taken together, our results clearly suggest that Ibrutinib can be successfully explored as an effective therapeutic approach for melanomas.

C-X-C chemokine receptor type 4 (CXCR4) is critical for homeostasis of the adaptive and innate immune system in some CNS diseases. Bruton's tyrosine kinase (BTK) is an essential kinase that regulates inflammation in immune cells through multiple signaling pathways. This study aims to explore the effect of CXCR4 and BTK on neuroinflammation in the pathogenesis of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Our results showed that the expression of CXCR4 and p-BTK increased significantly at 24 h after SAH in vivo and in vitro. Ibrutinib improved neurological impairment, BBB disruption, cerebral edema, lipid peroxidation, neuroinflammation and neuronal death at 24 h after SAH. Inhibition of BTK phosphorylation promoted the in vitro transition of hemin-treated proinflammatory microglia to the anti-inflammatory state, inhibited the p-P65 expression and microglial pyroptosis. NLRP3 deficiency can significantly reduce pyroptosis in SAH mice. Moreover, CXCR4 inhibition can suppress NLRP3-mediated pyroptosis, NF-κB activation and NOX2 expression in vitro, and ibrutinib can abolish CXCR4-aggravated BBB damage and pyroptosis in EBI after SAH. The levels of CXCR4 in CSF of SAH patients is significantly increased, and it is positively correlated with GSDMD and IL-1β levels, and have a moderate diagnostic value for outcome at 6-month follow-up. Our findings revealed the effect of CXCR4 and P-BTK on NLRP3-mediated pyroptosis and lipid peroxidation after SAH in vivo and in vitro, and the potential diagnostic role of CXCR4 in CSF of SAH patients. Inhibition of CXCR4-BTK axis can significantly attenuate NLRP3-mediated pyroptosis and lipid peroxidation by regulating NF-κB activation in EBI after SAH.

Enhancer of zeste homolog 2 (EZH2) and Bruton's tyrosine kinase (BTK) are both key factors involved in the development and progression of hematological malignancies. Clinical studies have demonstrated the potential of various EZH2 inhibitors, which target the methyltransferase activity of EZH2, for the treatment of lymphomas. However, despite their ability to effectively reduce the H3K27me3 levels, these inhibitors have shown limited efficacy in blocking the proliferation of lymphoma cells. To overcome this challenge, we employed a hydrophobic tagging approach utilizing MS1943, a selective EZH2 degrader. In this study, we investigated the inhibitory effects of two drugs, the FDA-approved EZH2 inhibitor Tazemetostat, currently undergoing clinical trials, and the novel drug MS1943, on Burkitt's lymphoma. Furthermore, we assessed the potential synergistic effect of combining these drugs with the BTK inhibitor Ibrutinib. In this study, we evaluated the effects of combination therapy with MS1943 and Ibrutinib on the proliferation of three Burkitt's lymphoma cell lines, namely RPMI1788, Ramos, and Daudi cells. Our results demonstrated that the combination of MS1943 and Ibrutinib significantly suppressed cell proliferation to a greater extent compared to the combination of Tazemetostat and Ibrutinib. Additionally, we investigated the underlying mechanisms of action and found that the combination therapy of MS1943 and Ibrutinib led to the upregulation of miR29B-mediated p53- upregulated modulator of apoptosis PUMA, BAX, cleaved PARP, and cleaved caspase-3 in Burkitt's lymphoma cells. These findings highlight the potential of this innovative therapeutic strategy as an alternative to traditional EZH2 inhibitors, offering promising prospects for improving treatment outcomes in Burkitt's lymphoma. [ABSTRACT FROM AUTHOR]

Constitutively active kinases play a crucial role in carcinogenesis, and their inhibition is a common target for molecular tumor therapy. We recently discovered the expression of two oncogenic isoforms of Bruton's Tyrosine Kinase (BTK) in head and neck squamous cell carcinoma (HNSCC), Btk-p80 and BTK-p65. However, the precise role of BTK in HNSCC remains unclear. Analyses of a tissue microarray containing benign and malignant as well as inflammatory tissue samples of the head and neck region revealed the preferential expression of BTK-p80 in malignant tissue, whereas BTK-p65 expression was confirmed in over 80% of analyzed metastatic head and neck tumor cases. Therefore, processes associated with metastasis, like cancer stem cell (CSC) enrichment and the epithelial–mesenchymal transition (EMT), which in turn depend on an appropriate cytokine milieu, were analyzed. Treatment of HNSCC-derived cell lines cultured under 3D conditions with the BTK inhibitor AVL-292 caused reduced sphere formation, which was accompanied by reduced numbers of ALDH1A1+ CSCs as well as biological changes associated with the EMT. Moreover, we observed reduced NF-κB expression as well as altered NF-κB dependent pro-tumorigenic and EMT-associated cytokine release of IL-6, IFNγ, and TNFα when BTK activity was dampened. Therefore, an autocrine regulation of the oncogenic BTK-dependent process in HNSCC can be suggested, with BTK inhibition expected to be an effective treatment option for HNSCC. [ABSTRACT FROM AUTHOR]

Background: Bruton's tyrosine kinase (BTK) is a key signaling node in B cell receptor (BCR) and Fc receptor (FcR) signaling. BTK inhibitors (BTKi) are an emerging oral treatment option for patients suffering from multiple sclerosis (MS). Remibrutinib (LOU064) is a potent, highly selective covalent BTKi with a promising preclinical and clinical profile for MS and other autoimmune or autoallergic indications. Methods: The efficacy and mechanism of action of remibrutinib was assessed in two different experimental autoimmune encephalomyelitis (EAE) mouse models for MS. The impact of remibrutinib on B cell-driven EAE pathology was determined after immunization with human myelin oligodendrocyte glycoprotein (HuMOG). The efficacy on myeloid cell and microglia driven neuroinflammation was determined in the RatMOG EAE. In addition, we assessed the relationship of efficacy to BTK occupancy in tissue, ex vivo T cell response, as well as single cell RNA-sequencing (scRNA-seq) in brain and spinal cord tissue. Results: Remibrutinib inhibited B cell-dependent HuMOG EAE in dose-dependent manner and strongly reduced neurological symptoms. At the efficacious oral dose of 30 mg/kg, remibrutinib showed strong BTK occupancy in the peripheral immune organs and in the brain of EAE mice. Ex vivo MOG-specific T cell recall response was reduced, but not polyclonal T cell response, indicating absence of non-specific T cell inhibition. Remibrutinib also inhibited RatMOG EAE, suggesting that myeloid cell and microglia inhibition contribute to its efficacy in EAE. Remibrutinib did not reduce B cells, total Ig levels nor MOG-specific antibody response. In brain and spinal cord tissue a clear anti-inflammatory effect in microglia was detected by scRNA-seq. Finally, remibrutinib showed potent inhibition of in vitro immune complex-driven inflammatory response in human microglia. Conclusion: Remibrutinib inhibited EAE models by a two-pronged mechanism based on inhibition of pathogenic B cell autoreactivity, as well as direct anti-inflammatory effects in microglia. Remibrutinib showed efficacy in both models in absence of direct B cell depletion, broad T cell inhibition or reduction of total Ig levels. These findings support the view that remibrutinib may represent a novel treatment option for patients with MS. [ABSTRACT FROM AUTHOR]

Zanubrutinib is a second‐generation Bruton tyrosine kinase inhibitor that is primarily metabolized by CYP3A enzymes. Previous drug–drug interaction (DDI) studies have demonstrated that co‐administration of zanubrutinib with rifampin, a strong CYP3A inducer, reduces zanubrutinib plasma concentrations, potentially impacting activity. The impact of the co‐administration of zanubrutinib with less potent CYP3A inducers is unclear. This phase 1, open‐label, fixed‐sequence DDI study evaluated the pharmacokinetics, safety, and tolerability of zanubrutinib when co‐administered with steady‐state rifabutin, a known CYP3A inducer less potent than rifampin, in 13 healthy male volunteers (NCT04470908). Co‐administration of zanubrutinib with rifabutin resulted in a less than 2‐fold reduction of zanubrutinib exposures. Overall, zanubrutinib was well tolerated. The results of this study provide useful information for the evaluation of the DDI between rifabutin and zanubrutinib. In conjunction with safety and efficacy data from other clinical studies, these results will be taken into consideration to determine the appropriate dose recommendation of zanubrutinib when co‐administered with CYP3A inducers. [ABSTRACT FROM AUTHOR]

Tingyu Cao,1 Zengguang Wang,2 Xiaodong Zhu1 1Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China; 2Department of Neurosurgery, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, People’s Republic of ChinaCorrespondence: Xiaodong Zhu, Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China, Tel +86 13312142939, Email zxd3516@tmu.edu.cn Zengguang Wang, Department of Neurosurgery, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China, Email wangzengguang@tmu.edu.cnAbstract: Bruton’s tyrosine kinase (BTK) is a central signaling node in B cells. BTK inhibition has witnessed great success in the treatment of B-cell malignancies. Additionally, in the immune system, BTK is also a prominent component linking a wide variety of immune-related pathways. Therefore, more and more studies attempting to dissect the role of BTK in autoimmune and inflammation progression have emerged in recent years. In particular, BTK expression was also found to be elevated within the central nervous system (CNS) during neuroinflammation. BTK inhibitors are capable of crossing the blood–brain barrier rapidly to modulate B cell functions, attenuate microglial activities and affect NLRP3 inflammasome pathways within the CNS to improve the outcome of diseases. Thus, BTK inhibition appears to be a promising approach to modulate dysregulated inflammation in the CNS and alleviate destruction caused by excessive inflammatory responses. This review will summarize the immunomodulatory mechanisms in which BTK is involved in the development of neurological diseases and discuss the therapeutic potential of BTK inhibition for the treatment of neuroinflammatory pathology.Keywords: BTK, BTK inhibition, BTK inhibitors, neuroinflammation

Abstract Bruton’s tyrosine kinase (BTK) is an essential component of multiple signaling pathways that regulate B cell and myeloid cell proliferation, survival, and functions, making it a promising therapeutic target for various B cell malignancies and inflammatory diseases. Five small molecule inhibitors have shown remarkable efficacy and have been approved to treat different types of hematological cancers, including ibrutinib, acalabrutinib, zanubrutinib, tirabrutinib, and orelabrutinib. The first-in-class agent, ibrutinib, has created a new era of chemotherapy-free treatment of B cell malignancies. Ibrutinib is so popular and became the fourth top-selling cancer drug worldwide in 2021. To reduce the off-target effects and overcome the acquired resistance of ibrutinib, significant efforts have been made in developing highly selective second- and third-generation BTK inhibitors and various combination approaches. Over the past few years, BTK inhibitors have also been repurposed for the treatment of inflammatory diseases. Promising data have been obtained from preclinical and early-phase clinical studies. In this review, we summarized current progress in applying BTK inhibitors in the treatment of hematological malignancies and inflammatory disorders, highlighting available results from clinical studies.

Alveolar type II (ATII) pneumocytes as defenders of the alveolus are critical to repairing lung injury. We investigated the ATII reparative response in coronavirus disease 2019 (COVID-19) pneumonia, because the initial proliferation of ATII cells in this reparative process should provide large numbers of target cells to amplify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus production and cytopathological effects to compromise lung repair. We show that both infected and uninfected ATII cells succumb to tumor necrosis factor-α (TNF)-induced necroptosis, Bruton tyrosine kinase (BTK)-induced pyroptosis, and a new PANoptotic hybrid form of inflammatory cell death mediated by a PANoptosomal latticework that generates distinctive COVID-19 pathologies in contiguous ATII cells. Identifying TNF and BTK as the initiators of programmed cell death and SARS-CoV-2 cytopathic effects provides a rationale for early antiviral treatment combined with inhibitors of TNF and BTK to preserve ATII cell populations, reduce programmed cell death and associated hyperinflammation, and restore functioning alveoli in COVID-19 pneumonia. [ABSTRACT FROM AUTHOR]

Ibrutinib is an oral inhibitor of Bruton tyrosine kinase that is approved by the United States Food and Drug Administration for several lymphoproliferative disorders and chronic graft-versus-host disease. To characterize cutaneous eruptions arising from ibrutinib and highlight overlap with epidermal growth factor receptor (EGFR) inhibitor–induced dermatologic adverse events. Single-center retrospective cohort of patients referred to the Skin Toxicities Program for treatment of cutaneous eruptions while taking ibrutinib. Among 19 patients, cutaneous eruptions manifested as facial-predominant papulopustular eruptions, petechiae, or ecchymoses, photosensitivity, panniculitis, xerosis, and clinical staphylococcal overgrowth. Most patients were able to continue ibrutinib therapy with focused treatment of their cutaneous toxicities. This study represents cases at a single tertiary care center and is limited to patients referred for toxicity. With the exception of petechiae, the cutaneous toxicities of ibrutinib overlap with those associated with selective EGFR inhibitors. We observed that these reactions can be successfully managed using approaches for EGFR inhibitor–induced cutaneous adverse events. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of two bacterial preparations: Spinosad and Bacillus thuringiensis kurstaki (Btk), which were applied at low concentrations (20 µg/l and 23 mg/l, respectively) on L4 larvae of the Culex pipiens. This application was used to assess their effects on mortality of the larvae, reproduction and cuticular hydrocarbons in adults resulting from this treatment. The results showed that both bacteria caused a death rate higher than 80 %, and the sub-lethal doses, despite being less toxic to mosquitoes, caused disturbances in the fecundity and fertility of the adults emerging from treated larvae. The use of sublethal doses of Spinosad induced a quantitative increase in cuticular hydrocarbons at a rate of 36 % to 42 % in treated males and females, respectively. Furthermore, the sublethal dose of Btk causes a reduction in the cuticular hydrocarbons by 59–64 % in both sexes. The results also show that there are no significant differences in the amounts of cuticular hydrocarbons in treated males and females. The results show that the two bacteria are promising as bio-insecticides against C. pipiens and could be good alternatives to chemical pesticides. [ABSTRACT FROM AUTHOR]