[Current status and challenges of AML treatment with FLT3 inhibitors].

FLT3 mutation is one of the most frequent genetic mutations in AML, identified in approximately 30% of patients, and FLT3-ITD mutation is considered a poor prognostic factor. Based on these molecular and clinical backgrounds, FLT3 mutations are considered promising therapeutic targets in AML, and intensive development of targeted therapeutics has been ongoing for more than two decades. Recently, combination of FLT3 inhibitors with intensive chemotherapy for untreated AML patients with FLT3 mutations and FLT3 inhibitor monotherapy for relapsed/refractory patients have been approved. In Japan, the combination of quizartinib and intensive chemotherapy for untreated FLT3-ITD-positive AML was approved in 2023. Clinical use of FLT3 inhibitors shows strong promise for improving the clinical outcomes of these AML patients with an extremely poor prognosis. Meanwhile, various resistance mechanisms to FLT3 inhibitors have been identified, including the emergence of resistance-associated mutations, and attenuated inhibitory effects of FLT3 inhibitors involving the bone marrow microenvironment surrounding AML cells. Thus, future efforts should aim to optimize combination therapy based on the characteristics of each FLT3 inhibitor, develop biomarkers that could inform treatment selection, and to better understand these resistance mechanisms and develop methods for overcoming them.

Selective Tyrosine Kinase 2 (TYK2) Inhibition in Plaque Psoriasis.

Members of the Janus kinase (JAK) superfamily, comprising tyrosine kinase 2 (TYK2) and JAK1, JAK2, and JAK3, mediate signaling by cytokines (eg, interleukin [IL]-23) involved in psoriasis pathogenesis. Binding of IL-23 to its receptor activates TYK2 and JAK2, which trigger signal transducer and activator of transcription (STAT) translocation to the nucleus to regulate target gene transcription, including genes of proinflammatory mediators such as IL-17. Physiologically, TYK2 solely mediates immune function, whereas JAK1,2,3 mediate broad systemic and immune functions. Inhibition of individual JAK family members is being evaluated in many dermatologic indications, including psoriasis. Selective TYK2 inhibition is therefore expected to be associated with few adverse effects in patients with psoriasis. People with genetic mutations leading to loss of function of TYK2 are protected from the development of psoriasis without an increased risk of infections or malignancies. In contrast, treatments with JAK1,2,3 inhibitors are associated with various systemic effects. We review the unique allosteric mechanism of action of the selective TYK2 inhibitor, deucravacitinib, which binds to the TYK2 regulatory (pseudokinase) domain, and the mechanisms of action of JAK1,2,3 inhibitors, which bind to the adenosine 5'-triphosphate-binding active (catalytic) site in the kinase domains of JAK1,2,3. Deucravacitinib, which is approved for the treatment of moderate to severe plaque psoriasis in adults in the United States and several other countries, represents a novel, targeted systemic treatment approach with a favorable safety profile. J Drugs Dermatol. 2024;23(8):645-652.  doi:10.36849/JDD.8293.

Impact of protein and small molecule interactions on kinase conformations.

Protein kinases act as central molecular switches in the control of cellular functions. Alterations in the regulation and function of protein kinases may provoke diseases including cancer. In this study we investigate the conformational states of such disease-associated kinases using the high sensitivity of the kinase conformation (KinCon) reporter system. We first track BRAF kinase activity conformational changes upon melanoma drug binding. Second, we also use the KinCon reporter technology to examine the impact of regulatory protein interactions on LKB1 kinase tumor suppressor functions. Third, we explore the conformational dynamics of RIP kinases in response to TNF pathway activation and small molecule interactions. Finally, we show that CDK4/6 interactions with regulatory proteins alter conformations which remain unaffected in the presence of clinically applied inhibitors. Apart from its predictive value, the KinCon technology helps to identify cellular factors that impact drug efficacies. The understanding of the structural dynamics of full-length protein kinases when interacting with small molecule inhibitors or regulatory proteins is crucial for designing more effective therapeutic strategies.

Pulsatillic acid as a potential inhibitor of protein kinase C-alpha in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a global health concern with a significant impact on morbidity and mortality. Small molecule inhibitors targeting genetic mutations like EGFR and ALK have shown promise in NSCLC treatment. This study focuses on Protein Kinase C-alpha (PKCα), implicated in NSCLC pathogenesis. Overexpression of PKCα correlates with advanced disease stages. Preclinical studies suggest its inhibition can suppress NSCLC cell growth. The research employs molecular docking to identify Pulsatillic acid (PA) as a potential PKCα inhibitor. ADMET predictions support PA's candidacy and PASS analysis and Swiss Target Prediction reveal its biological properties. Fluorescence-based binding assays demonstrate PA's inhibitory potency on PKCα, aligning with molecular docking findings. Cytotoxicity assays show PA's minimal impact on HEK-293 cell viability, with an IC50 of 21.03 µM in A549 cells. mRNA expression analysis in A549 cells indicates PA's potential inhibitory effect on PKCα. In conclusion, this study highlights that PA may emerge as a promising therapeutic candidate for NSCLC, emphasizing the need for further research, validation, and exploration of its translational potential. The study contributes valuable insights into NSCLC treatment strategies, emphasizing the significance of targeting PKCα.

Protein Kinase A Inhibitor Attenuates the Antinociceptive Effect of NMDA-Receptor Channel Antagonists in the Capsaicin Test in Mice.

Acute nociceptive pain in mice caused by subcutaneous (intraplantar) injection of TRPV1 ion channel agonist capsaicin (1.6 µg/mouse) and the effects of protein kinase A inhibitor H-89 (0.05 mg/mouse, intraplantar injection) and NMDA receptor channel antagonists MK-801 (7.5 and 15 µg/mouse, topical application) and hemantane (0.5 mg/mouse, topical application) on the pain were assessed. MK-801 and hemantane were found to reduce the duration of the pain response. H-89 did not significantly affect the pain in animals, but preliminary administration of this drug abolished the antinociceptive effect of MK-801 (7.5 µg/mouse) and weakens the effect of hemantane (0.5 mg/mouse).

Efficacy of BRAF/MEK-inhibitor therapy for epithelioid glioblastoma with a novel BRAFV600 mutation.

Epithelioid glioblastoma (eGB), a very aggressive and rare brain tumour, is associated with a dismal median overall survival. Effective therapies for patients with eGB, particularly with leptomeningeal dissemination, are still lacking. Here, we describe a case of a 25-year-old male diagnosed with an intramedullary cervical tumour with subsequent leptomeningeal disease. Histopathology identified a highly necrotising, epithelioid-type tumour with high cell density, most compatible with the diagnosis of an eGB. DNA analysis revealed an unprecedented B-Raf protooncogene, serine/threonine kinase (BRAF) gene variant in exon 15 (ENST00000288602.6, c.1799_1810delinsATG, p.(V600_W604delinsDG)), triggering activation of the mitogen-activated protein kinase (MAPK) pathway. Consequently, we initiated MAPK inhibitor (MAPKi) therapy, utilizing a combination of BRAF and mitogen-activated protein kinase kinase (MEK) inhibitors. Liquid chromatography-tandem mass spectrometry analysis confirmed the drugs' presence in the patient's cerebrospinal fluid, indicating their capacity to cross the blood-brain barrier. Remarkably, the patient responded very well to therapy and transitioned from a near-comatose state to significantly improved health, sustained for over three months. This study highlights that MAPKi, particularly targeted towards novel BRAFV600 mutations, might offer promising advancements in eGB treatment strategies.

Therapeutic advances of targeting receptor tyrosine kinases in cancer.

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

Targeting PI3K family with small-molecule inhibitors in cancer therapy: current clinical status and future directions.

The Phosphatidylinositol-3-kinase (PI3K) family is well-known to comprise three classes of intracellular enzymes. Class I PI3Ks primarily function in signaling by responding to cell surface receptor stimulation, while class II and III are more involved in membrane transport. Under normal physiological conditions, the PI3K signaling network orchestrates cell growth, division, migration and survival. Aberrant activation of the PI3K signaling pathway disrupts cellular activity and metabolism, often marking the onset of cancer. Currently, the Food and Drug Administration (FDA) has approved the clinical use of five class I PI3K inhibitors. These small-molecule inhibitors, which exhibit varying selectivity for different class I PI3K family members, are primarily used in the treatment of breast cancer and hematologic malignancies. Therefore, the development of novel class I PI3K inhibitors has been a prominent research focus in the field of oncology, aiming to enhance potential therapeutic selectivity and effectiveness. In this review, we summarize the specific structures of PI3Ks and their functional roles in cancer progression. Additionally, we critically evaluate small molecule inhibitors that target class I PI3K, with a particular focus on their clinical applications in cancer treatment. Moreover, we aim to analyze therapeutic approaches for different types of cancers marked by aberrant PI3K activation and to identify potential molecular targets amenable to intervention with small-molecule inhibitors. Ultimately, we propose future directions for the development of therapeutic strategies that optimize cancer treatment outcomes by modulating the PI3K family.

CaMK II in Cardiovascular Diseases, Especially CaMK II-δ: Friends or Enemies.

Cardiovascular diseases (CVDs) tend to affect the young population and are associated with a significant economic burden and psychological distress to the society and families. The physiological and pathological processes underlying CVDs are complex. Ca2+/calmodulin-dependent kinase II (CaMK II), a protein kinase, has multiple biological functions. It participates in multiple pathological processes and plays a central role in the development of CVDs. Based on this, this paper analyzes the structural characteristics and distribution of CaMK II, the mechanism of action of CaMK II, and the relationship between CaMK II and CVDs, including ion channels, ischemia-reperfusion injury, arrhythmias, myocardial hypertrophy, cardiotoxicity, hypertension, and dilated cardiomyopathy. Given the different regulatory mechanisms of different isoforms of CaMK II, the clinical use of specific targeted inhibitors or novel compounds should be evaluated in future research to provide new directions.

[Advances in basic and clinical research of flumatinib].

Chronic myelogenous leukemia (CML) is a hematological malignancy originating from the pluripotent hematopoietic stem cells. Imatinib is the first generation of small molecule tyrosine kinase inhibitors (TKI) that revolutionized the treatment of CML. Flumatinib, as a novel oral TKI that independently developed in China, which can be used as a preferred treatment for CML. Basic researches suggested that the inhibitory effect of flumatinib on CML cell lines is stronger than imatinib. Flumatinib demonstrated that it has better efficacy than imatinib on CML in clinical trials and in real world studies. Flumatinib also showed a higher potency against CML with specific mutations, Ph(+) acute lymphoblastic leukemia and some solid tumors. The adverse events are manageable and tolerable.

Asciminib: the next-generation bullet for first-line treatment of chronic myeloid leukemia.

The standard of care for chronic myeloid leukemia (CML) involves tyrosine kinase inhibitors (TKIs), which suppress tyrosine kinase activity of BCR::ABL1. Hochhaus et al. reported that asciminib, a BCR::ABL1 inhibitor specifically targeting the ABL myristoyl pocket, showed superior efficacy and favorable safety compared with TKIs in the phase 3 ASC4FIRST trial in patients with newly diagnosed chronic-phase CML.1.

Changes in Red Cell Morphology and Haematological Laboratory Parameters Associated With Alectinib.

BACKGROUND: Alectinib is a second-generation anaplastic lymphoma kinase (ALK) inhibitor indicated for ALK-mutated non-small-cell lung cancer. Recently, the association between alectinib and red cell morphological abnormalities has been reported in a few case series. This retrospective observational study aims to determine the frequency of occurrence of acanthocytosis in patients taking alectinib and to evaluate the red cell indices, biochemical markers of haemolysis and eosin-5-maleimide (EMA) binding assay results in patients receiving alectinib. METHODS: Patients who were on alectinib and had a complete blood count test performed in Queen Elizabeth Hospital Haematology Laboratory between 1 May 2021 and 31 August 2021 were included in the study. Haematological investigations that had been performed before and after the commencement of alectinib were reviewed. RESULTS: Fifty patients receiving alectinib were evaluated in this analysis. One hundred per cent of patients showed 3+ acanthocytes on the peripheral blood smears. Compared with the test results before starting alectinib, the post-alectinib blood tests showed a significantly lower haemoglobin concentration, red blood cell count and haematocrit; and a significantly higher mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration and red cell distribution width. All the tested patients showed a marked reduction in EMA mean channel fluorescence compared with normal control. CONCLUSION: Our cohort revealed that alectinib caused significant acanthocytosis in all patients. Alectinib was also associated with changes in red cell indices and biochemical markers of haemolysis, compatible with a spherocytic and anisopoikilocytic morphology with haemolysis. Patients on alectinib had reduced EMA binding.

In vivo Bruton's tyrosine kinase inhibition attenuates alcohol-associated liver disease by regulating CD84-mediated granulopoiesis.

Severe alcohol-associated hepatitis (AH) is a life-threatening form of alcohol-associated liver disease. Liver neutrophil infiltration is a hallmark of AH, yet the effects of alcohol on neutrophil functions remain elusive. Identifying therapeutic targets to reduce neutrophil-mediated liver damage is essential. Bruton's tyrosine kinase (BTK) plays an important role in neutrophil development and function; however, the role of BTK in AH is unknown. Using RNA sequencing of circulating neutrophils, we found an increase in Btk expression (P = 0.05) and phosphorylated BTK (pBTK) in patients with AH compared with healthy controls. In vitro, physiologically relevant doses of alcohol resulted in a rapid, TLR4-mediated induction of pBTK in neutrophils. In a preclinical model of AH, administration of a small-molecule BTK inhibitor (evobrutinib) or myeloid-specific Btk knockout decreased proinflammatory cytokines and attenuated neutrophil-mediated liver damage. We found that pBTK was essential for alcohol-induced bone marrow granulopoiesis and liver neutrophil infiltration. In vivo, BTK inhibition or myeloid-specific Btk knockout reduced granulopoiesis, circulating neutrophils, liver neutrophil infiltration, and liver damage in a mouse model of AH. Mechanistically, using liquid chromatography-tandem mass spectrometry, we identified CD84 as a kinase target of BTK, which is involved in granulopoiesis. In vitro, CD84 promoted alcohol-induced interleukin-1ß and tumor necrosis factor-α in primary human neutrophils, which was inhibited by CD84-blocking antibody treatment. Our findings define the role of BTK and CD84 in regulating neutrophil inflammation and granulopoiesis, with potential therapeutic implications in AH.

Branched-chain amino acid transaminase 1 confers EGFR-TKI resistance through epigenetic glycolytic activation.

Third-generation EGFR tyrosine kinase inhibitors (TKIs), exemplified by osimertinib, have demonstrated promising clinical efficacy in the treatment of non-small cell lung cancer (NSCLC). Our previous work has identified ASK120067 as a novel third-generation EGFR TKI with remarkable antitumor effects that has undergone New Drug Application (NDA) submission in China. Despite substantial progress, acquired resistance to EGFR-TKIs remains a significant challenge, impeding the long-term effectiveness of therapeutic approaches. In this study, we conducted a comprehensive investigation utilizing high-throughput proteomics analysis on established TKI-resistant tumor models, and found a notable upregulation of branched-chain amino acid transaminase 1 (BCAT1) expression in both osimertinib- and ASK120067-resistant tumors compared with the parental TKI-sensitive NSCLC tumors. Genetic depletion or pharmacological inhibition of BCAT1 impaired the growth of resistant cells and partially re-sensitized tumor cells to EGFR TKIs. Mechanistically, upregulated BCAT1 in resistant cells reprogrammed branched-chain amino acid (BCAA) metabolism and promoted alpha ketoglutarate (α-KG)-dependent demethylation of lysine 27 on histone H3 (H3K27) and subsequent transcriptional derepression of glycolysis-related genes, thereby enhancing glycolysis and promoting tumor progression. Moreover, we identified WQQ-345 as a novel BCAT1 inhibitor exhibiting antitumor activity both in vitro and in vivo against TKI-resistant lung cancer with high BCAT1 expression. In summary, our study highlighted the crucial role of BCAT1 in mediating resistance to third-generation EGFR-TKIs through epigenetic activation of glycolysis in NSCLC, thereby supporting BCAT1 as a promising therapeutic target for the treatment of TKI-resistant NSCLC.

Aptamer-Based Enforced Phosphatase-Recruiting Chimeras Inhibit Receptor Tyrosine Kinase Signal Transduction.

Aberrant phosphorylation of receptor tyrosine kinases (RTKs) is usually involved in tumor initiation, progression, and metastasis. However, developing specific and efficient molecular tools to regulate RTK phosphorylation remains a considerable challenge. In this study, we reported novel aptamer-based chimeras to inhibit the phosphorylation of RTKs, such as c-Met and EGFR, by enforced recruitment of a protein tyrosine phosphatase receptor type F (PTPRF). Our studies revealed that aptamer-based chimeras displayed a generic and potent inhibitory effect on RTK phosphorylation induced by growth factor or auto-dimerization in different cell lines and modulated cell biological behaviors by recruiting PTPRF. Furthermore, based on angstrom accuracy of the DNA duplex, the maximum catalytic radius of PTPRF was determined as ∼25.84 nm, providing a basis for the development of phosphatase-recruiting strategies. Taken together, our study provides a generic methodology not only for selectively mediating RTK phosphorylation and cellular biological processes but also for developing novel therapeutic drugs.

Design and synthesis of novel Thiazolo[5,4-b]pyridine derivatives as potent and selective EGFR-TK inhibitors targeting resistance Mutations in non-small cell lung cancer.

A novel series of substituted thiazolo[5,4-b]pyridine analogues were rationally designed and synthesized via a multi-step synthetic pathway, including Suzuki cross-coupling reaction. The anticancer activity of all forty-five synthesized derivatives was evaluated against HCC827, H1975, and A549 cancer cell lines utilizing the standard MTT assay. A significant number of the thiazolo[5,4-b]pyridine derivatives exhibited potent anticancer activity. Notably, compounds 10b, 10c, 10h, 10i, and 10k emerged as the most promising anticancer agents. The lead compound, N-(3-(6-(2-aminopyrimidin-5-yl)thiazolo[5,4-b]pyridin-2-yl)-2-methylphenyl)-2,5-difluorobenzenesulfonamide (10k), displayed remarkable potency with IC50 values of 0.010 µM, 0.08 µM, and 0.82 µM against the HCC827, NCI-H1975 and A-549 cancer cell lines, respectively, which were comparable to the clinically approved drug Osimertinib. Importantly, the potent derivatives 10b, 10c, 10h, 10i, and 10k exhibited selective cytotoxicity towards cancer cells and showing no toxicity against the normal BEAS-2B cell line at concentrations exceeding 35 µM. Mechanistic studies revealed that the active compound 10k acts as an EGFR-TK autophosphorylation inhibitor in HCC827 cells. Furthermore, apoptosis assays demonstrated that compound 10k induced substantial early apoptosis (31.9 %) and late apoptosis (8.8 %) in cancer cells, in contrast to the control condition exhibiting only 2.0 % early and 1.6 % late apoptosis. Molecular docking simulations of the synthesized compounds revealed that they formed essential hinge interactions and established hydrogen bonding with Cys797, indicating potential target engagement. These findings highlight the potential of the synthesized thiazolo [(Woodburn, 1999; Zigrossi et al., 2022) 5,45,4-b]pyridine derivatives as promising anticancer agents, warranting further investigation for the development of novel targeted therapies against non-small cell lung cancer.

PD-L1 induces autophagy and primary resistance to EGFR-TKIs in EGFR-mutant lung adenocarcinoma via the MAPK signaling pathway.

Resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is a significant cause of treatment failure and cancer recurrence in non-small cell lung cancer (NSCLC). Approximately 30% of patients with EGFR-activating mutations exhibit primary resistance to EGFR-TKIs. However, the potential mechanisms of primary resistance to EGFR-TKIs remain poorly understood. Recent studies have shown that increased expression of programmed death ligand-1 (PD-L1) is associated with EGFR-TKIs resistance. Therefore, the present study aimed to investigate the mechanism of PD-L1 in primary resistance to EGFR-TKIs in EGFR-mutant lung adenocarcinoma (LUAD) cells. We found that PD-L1 was associated with poor prognosis in patients with EGFR-mutant LUAD, while the combination of EGFR-TKIs with chemotherapy could improve its therapeutic efficacy. In vitro and in vivo experiments revealed that PD-L1 promoted the proliferation and autophagy and inhibited the apoptosis of LUAD cells. Mechanistic studies demonstrated that upregulation of PD-L1 was critical in inducing autophagy through the mitogen-activated protein kinase (MAPK) signaling pathway, which was beneficial for tumor progression and the development of gefitinib resistance. Furthermore, we found that gefitinib combined with pemetrexed could synergistically enhance antitumor efficacy in PD-L1-overexpression LUAD cells. Overall, our study demonstrated that PD-L1 contributed to primary resistance to EGFR-TKIs in EGFR-mutant LUAD cells, which may be mediated by inducing autophagy via the MAPK signaling pathway. These findings not only help improve the prognosis of patients with EGFR-mutant LUAD but also provide a reference for the research of other cancer types.

Bruton's tyrosine kinase inhibition ameliorated neuroinflammation during chronic white matter ischemia.

Chronic cerebral hypoperfusion (CCH), a disease afflicting numerous individuals worldwide, is a primary cause of cognitive deficits, the pathogenesis of which remains poorly understood. Bruton's tyrosine kinase inhibition (BTKi) is considered a promising strategy to regulate inflammatory responses within the brain, a crucial process that is assumed to drive ischemic demyelination progression. However, the potential role of BTKi in CCH has not been investigated so far. In the present study, we elucidated potential therapeutic roles of BTK in both in vitro hypoxia and in vivo ischemic demyelination model. We found that cerebral hypoperfusion induced white matter injury, cognitive impairments, microglial BTK activation, along with a series of microglia responses associated with inflammation, oxidative stress, mitochondrial dysfunction, and ferroptosis. Tolebrutinib treatment suppressed both the activation of microglia and microglial BTK expression. Meanwhile, microglia-related inflammation and ferroptosis processes were attenuated evidently, contributing to lower levels of disease severity. Taken together, BTKi ameliorated white matter injury and cognitive impairments induced by CCH, possibly via skewing microglia polarization towards anti-inflammatory and homeostatic phenotypes, as well as decreasing microglial oxidative stress damage and ferroptosis, which exhibits promising therapeutic potential in chronic cerebral hypoperfusion-induced demyelination.