Amplification of the MYCN proto-oncogene serves as a key marker of aggressive disease and poor treatment outcomes in certain pediatric tumors originating from the nervous system, including neuroblastoma and medulloblastoma. However, the complex nature of the challenging MYCN protein underscores the urgent need for additional targets and therapies to tackle neuroblastoma and medulloblastoma. In this study, with a primary focus on neuroblastoma and the aim of also benefiting children with medulloblastoma, we identified FLIX5, a small compound that exhibits broad cytotoxicity against both neuroblastoma and medulloblastoma cells, primarily by triggering apoptosis. Furthermore, FLIX5 enhances the cholesterol dependency of neuroblastoma cells under conditions where mitochondrial function is impaired. FLIX5 as well shows a synergistic effect when combined with vincristine, a conventional anticancer drug, against neuroblastoma cells and organoids. Through proteome integral solubility alteration, computational molecular docking predictions, and cellular thermal shift assays for target identification and validation, FLIX5 reveals EPLIN (Epithelial Protein Lost In Neoplasm) as a previously unexplored drug target. EPLIN is involved in several cellular processes, including cholesterol uptake and mitochondrial function. The discovery of FLIX5 targeting EPLIN presents new opportunities for treating malignant pediatric tumors, with the potential to target chemoresistant dormant cancer cells and broaden its therapeutic applications to other tumor types.

Treatment of B-cell malignancies with the PI3K inhibitor (PI3Ki) idelalisib often results in high toxicity and resistance, with limited treatment alternatives for relapsed/refractory patients since idelalisib is recommended as a later or last line therapy. To investigate resistance mechanisms and identify alternative treatments, we studied functional phenotypes of idelalisib-resistant B-cell malignancy models. The idelalisib-resistant KARPAS1718 model remained sensitive to Bcl-2 inhibitors (Bcl-2i), whereas the resistant VL51 model showed reduced sensitivity compared to parental cells. Sensitivity correlated with phosphorylation and expression of the Bcl-2 family members Bcl-2 and Bim. Target addiction scoring revealed high dependence on the proteasome, and proteasome inhibitors (PI) were effective across models and in primary chronic lymphocytic leukemia (CLL) cells, independently of their PI3Ki- or Bcl-2i-sensitivities. PI treatment consistently upregulated Bim and Mcl-1, while Bcl-2 increased in KARPAS1718 and CLL cells. Bcl-2i plus PI combinations led to an additive effect in these models. A multi-refractory CLL patient in the IMPRESS-Norway trial (NCT04817956) treated with Bcl-2i plus PI showed initial clinical improvement but relapsed within four months. Treatment induced Bim and Mcl-1 upregulation and reduced cytotoxic CD8⁺ T-cell and CD56^dim NK-cell populations. Our findings suggest that PIs may overcome resistance to targeted therapies, and warrant further studies to optimize clinical responses.

The ubiquitin‒proteasome system (UPS), an intracellular protein degradation pathway, plays an important role in regulating tumorigenesis and development. Ubiquitination factor E4B (UBE4B/UFD2) has been shown to be associated with the development of several cancers. The aim of this study was to reveal the functional significance of UBE4B in gastric cancer (GC) development and its important mechanism. Bioinformatics analysis, immunohistochemistry (IHC), western blotting, and real-time PCR were performed to detect UBE4B expression in human GC samples and GC cell lines and a mouse xenograft tumour model was established. Our investigation revealed that UBE4B is highly expressed in GC and promotes the proliferation, migration and invasion of GC cells. The quantitative Tandem Mass Tag (TMT) analysis revealed that FAT oncogenic homologue 4 (FAT4) is a downstream gene of UBE4B. Western blot experiments and transmission electron microscopy (TEM) results for biological samples revealed that UBE4B inhibits autophagy in GC cells and directly binds to and degrades FAT4 through ubiquitination. These results suggest that UBE4B can inhibit autophagy and promote GC progression by mediating FAT4 ubiquitination and degradation, and our findings provide a new potential therapeutic target for GC management.

Stabilization of hypoxia-inducible factor 1 alpha (HIF1α), which plays a pivotal role in regulating cellular responses to insufficient oxygen, is implicated in cancer progression, particularly epithelial-mesenchymal transition and metastatic dissemination. Despite its crucial role in tumorigenesis, the precise mechanisms governing HIF1α stabilization under varying tumor microenvironmental conditions are not fully understood. In this study, we show that stabilization of HIF1α in metastasizing melanoma under mild hypoxia is regulated primarily by mitochondrial reactive oxygen species (ROS) rather than by reduced oxygen levels. Activated HIF1α suppresses the expression of cyclophilin D (CypD), a regulator of the mitochondrial permeability transition pore (mPTP), as a reciprocal regulatory mechanism to sustain HIF1 signaling via upregulation of microRNAs miR-23a and miR-27a. Reduced expression of CypD leads to mPTP closure, resulting in elevated mitochondrial calcium accumulation and enhanced oxidative phosphorylation, which in turn increases mitochondrial ROS levels. The ROS then inhibits a prolyl hydroxylase, establishing a pseudohypoxic state that stabilizes HIF1α even in the presence of oxygen. This HIF1-reinforced and mitochondria-driven pseudohypoxic induction is essential for maintaining HIF1 signaling under conditions of mild hypoxia or transient increases in oxygen levels during melanoma metastasis. Overexpression of CypD reversed the pseudohypoxic state and potently inhibited melanoma metastasis. Thus, mitochondria-driven pseudohypoxic induction is critical for sustaining HIF1 signaling in metastasizing cancer cells and can be exploited to develop anti-metastatic therapies.

The JAK2V617F mutation is associated with increased cardiovascular risk, including ischaemic stroke. This study investigates the prevalence of additional mutations in ischaemic cerebrovascular patients with and without JAK2V617F to better understand the mechanisms contributing to thrombotic risk. We examined 63 patients with the JAK2V617F mutation and 126 matched controls from a cohort of 591 ischaemic cerebrovascular patients. Somatic mutations were assessed using targeted next-generation sequencing (NGS). Serum thromboinflammatory markers were evaluated in a subset of patients. Additional somatic mutations were more common in JAK2V617F-positive patients than in controls (47.6% vs. 30.2%, p = 0.028). Patients with JAK2V617F had a higher prevalence of other mutations with variant allele frequencies (VAFs) above 10% (23.8% vs. 7.9%, p = 0.005), a pattern that persisted in cases with JAK2V617F <1% (p = 0.019). In JAK2V617F-positive patients, additional somatic mutations were associated with higher monocyte levels, even when excluding myeloproliferative neoplasms patients (p = 0.011). Patients with other clonal haematopoiesis of indeterminate potential mutations exhibited higher vascular cell adhesion molecule 1 (p = 0.027), soluble urokinase plasminogen activator receptor (p = 0.010) and IL-10 (p = 0.045), as well as higher neutrophil to lymphocyte ratio (p = 0.002). Ischaemic cerebrovascular patients with the JAK2V617F mutation more frequently harbour other somatic mutations and at higher VAF. This may reflect a more advanced clonal profile with relevance for vascular risk in JAK2V617F-positive individuals.

Conventional treatments, including chemotherapy, immunotherapy, targeted therapy and radiotherapy, are effective clinical strategies for non-small cell lung cancer (NSCLC) patients, which can significantly improve life quality and prolong survival time. However, the application of drugs in NSCLC patients inevitably leads to therapeutic resistance. In recent years, many studies have shown that histone methyltransferases (HMTs), including both protein arginine methyltransferases (PRMTs) and lysine methyltransferases (KMTs), play pivotal roles in tumor initiation, progression, and treatment resistance. This review synthesizes current insights into histone methylation dynamics driving therapeutic resistance, with a focus on key HMTs and their mechanisms. Additionally, we discuss the molecular mechanisms underlying histone methylation-mediated therapeutic resistance and potential therapeutic strategies targeting histone methylation for overcoming therapeutic resistance in NSCLC.

Chimeric antigen receptor (CAR)-T cell therapy has proven to be a revolutionizing immunotherapeutic strategy for treating relapsed or refractory lymphoma, achieving remarkable clinical responses. However, there remain some challenges including treatment resistance and early relapse in a minor proportion of patients. The lymphoma tumor microenvironment (TME) is a heterogeneous and dynamic milieu composed of lymphoma cells, immune cells, stromal components, cytokines, and extracellular matrix proteins. CAR-T cell infusion alters the composition of TME and thus impact the endogenous immune response. Additionally, various components of the TME affect the persistence, activity and cytotoxicity of CAR-T cells, which is a key endogenous factor that impeding the efficacy of CAR-T cell therapy in lymphoma. Herein, we review the role of lymphoma TME on CAR-T cells, and discuss strategies targeting TME components to overcome resistance and improve the effectiveness of CAR-T cells.

Chimeric antigen receptor T (CAR-T) cell therapy, a type of precision immunotherapy, has shown promising outcomes in treating certain types of cancers, although limited by the antigen escape, suppression on the tumor microenvironment (TME), and CAR-T cell depletion. Molecularly targeted drugs can enhance the anti-cancer efficacy by targeting key signal transductions against cancers, providing a clue for optimizing the CAR-T cell therapy. Moreover, molecularly targeted drugs synergistically assist CAR-T cells to transform the TME, boost anti-cancer activities and inhibit immune escape. Their combination has rushed into the spotlight of research on individualized treatments for multiple myeloma (MM). In the present review, we described frequently used molecularly targeted drugs in the combination of CAR-T cell therapy against MM.

Chimeric antigen receptor-natural-killer (CAR-NK)-cells are a promising cancer cell therapy. Several features of CAR-NK-cells are suggesting an advantage over CAR-T-cells such as less complex manufacturing, "off-the-shelf" use and lower risks of cytokine release (CRS) and immune effector cell-associated neurotoxicity syndromes (ICANS). CAR-NK-cells derived from several sources are associated with promising pre-clinical and clinical results in haematological cancers. We comprehensively discuss the current landscape of CAR-NK-cell therapy in haematological cancers emphasizing recent progress and future directions. Additionally, we explore the biological mechanisms, engineering and sources of CAR-NK-cells. CAR-NK-cell therapy offers a safe, accessible and efficient option for haematological cancers.

Chimeric antigen receptor T cell (CAR-T) therapy targeting B-cell maturation antigen (BCMA) has emerged as a novel and effective modality for the treatment of relapsed or refractory multiple myeloma (RRMM), achieving remarkable therapeutic outcomes. However, relapse remains a major problem impeding the long-term efficacy of this therapy, with antigen-negative relapse being a particularly challenging issue. The mechanisms underlying BCMA antigen-negative relapse encompass a spectrum of phenomena, including diminished or lost tumor antigen expression, BCMA shedding, impaired antigen presentation, trogocytosis, antigen mutations, and alternative splicing. To overcome the problem of antigen-negative relapse in BCMA CAR-T therapy, a variety of strategies are being explored. These include dual/multi-specific CAR-T cell therapy, combination therapies with antibody-drug conjugates (ADCs) or bispecific T-cell engagers (BiTEs), integration with hematopoietic stem cell transplantation (HSCT), identification of novel targets, and the development of innovative cell therapies such as CAR-NK and CAR-M (CAR-Macrophage). Additionally, the optimization of CAR-T cells through gene editing technologies to enhance their durability and anti-tumor activity is a burgeoning area of research. In future, targeted BCMA CAR-T therapy is poised to place greater emphasis on individualization and precision medicine, combining multiple therapeutic approaches to reduce the incidence of relapse, thereby improving treatment efficacy and longevity.