Search Results (472)

The BCL2 family of proteins plays a pivotal role in regulating apoptosis and cellular homeostasis, making them critical therapeutic targets in cancer and other diseases characterized by pathological cell survival. BH3 mimetics, small molecules that selectively inhibit anti-apoptotic BCL2 family members, have achieved significant clinical success, particularly in hematologic malignancies. However, several challenges remain, including resistance mechanisms, toxicity (such as MCL1 inhibitor-associated cardiotoxicity), and the intricate balance between apoptotic and non-apoptotic functions. This review provides a comprehensive overview of BCL2 family biology, the development and clinical application and outcomes of BH3 mimetics, and the emerging resistance mechanism known as double-bolt locking. We also examine strategies to overcome resistance, including combination therapies and immunomodulatory approaches. Beyond oncology, we highlight the expanding therapeutic potential of BH3 mimetics in autoimmune, fibrotic, and infectious diseases, as well as regenerative and anti-aging medicine. Finally, we discuss predictive biomarkers and tissue-specific responses that inform precision therapy. Together, these insights underscore the promise of BH3 mimetics and the need for continued multidisciplinary research to optimize their clinical impact. Full article

The persistent residual tumor cells that survive after chemotherapy are a major cause of treatment failure, but their survival mechanisms remain largely elusive. These cancer cells are typically characterized by a quiescent state with suppressed activity of MYC and MTOR. We observed that the MYC-suppressed persistent triple-negative breast cancer (TNBC) cells are metabolically flexible and can upregulate mitochondrial oxidative phosphorylation (OXPHOS) genes and respiratory function (“OXPHOS-high” cell state) in response to DNA-damaging anthracyclines such as doxorubicin, but not to taxanes. The elevated biomass and respiratory function of mitochondria in OXPHOS-high persistent cancer cells were associated with mitochondrial elongation and remodeling, suggestive of increased mitochondrial fusion. A genome-wide CRISPR editing screen in doxorubicin-persistent OXPHOS-high TNBC cells revealed the BCL-XL gene as the top survival dependency in these quiescent tumor cells, but not in their untreated proliferating counterparts. Quiescent OXPHOS-high TNBC cells were highly sensitive to BCL-XL inhibitors, but not to inhibitors of BCL2 and MCL1. Interestingly, inhibition of BCL-XL in doxorubicin-persistent OXPHOS-high TNBC cells rapidly abrogated mitochondrial elongation and respiratory function, followed by caspase 3/7 activation and cell death. The platelet-sparing proteolysis-targeted chimera (PROTAC) BCL-XL degrader DT2216 enhanced the efficacy of doxorubicin against TNBC xenografts in vivo without induction of thrombocytopenia that is often observed with the first-generation BCL-XL inhibitors, supporting the development of this combinatorial treatment strategy for eliminating dormant tumor cells that persist after treatment with anthracycline-based chemotherapy. Full article

Anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-xL, and Mcl-1), are often overexpressed in cancer, which aids tumor growth and treatment resistance. As a result, these proteins are excellent candidates for novel anticancer drugs. Within this study a virtual library of betuline derivatives was built and screened for possible Bcl-2, Bcl-XL, and Mcl-1 inhibitors. For every target, molecular docking simulations were performed using two different engines (AutoDock Vina and Glide). The ligands that most frequently appeared among the top candidates were shortlisted after comparing the top-20 hits from both docking scoring functions. To assess binding stability, five of these promising compounds were chosen and run through 100 ns molecular dynamics (MD) simulations in complex with every target protein. Key persistent intermolecular contacts were identified from MD contact frequency histograms, and stability was evaluated using root-mean-square deviation (RMSD) profiles of protein–ligand complexes following equilibration. Additionally, Prime MM-GBSA binding energies (ΔG_bind) for the 15 docked complexes were computed, and ligand efficiency was reported. Two substances, BOxNaf1 and BT3, stood out among the screened derivatives as the most stable binders to all three Bcl-2 family targets according to the dual docking and MD analysis approach. When the MM-GBSA and RMSF/rGyr data are considered alongside docking and MD stability, BOxNaf1 and BOxPhCl1 emerge as the most compelling dual/multi-target candidates, whereas BT3, though MD stable, shows weaker MM-GBSA energetics and is retained as a lower-priority backup chemotype. Full article

Myeloproliferative neoplasms (MPNs) encompass three principal subtypes: polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These hematologic malignancies originate from clonal hematopoietic stem cells (HSCs) and exhibit pathological overproduction of myeloid lineage cells. Recent advances in molecular diagnostics, particularly the precise detection of core driver mutations (JAK2 V617F, CALR, and MPL) and non-driver mutations (ASXL1, TET2, SRSF2), has refined diagnostic precision and risk stratification. A variety of prognostic models for MPNs provide guidance for treatment. Treatment methods mainly include bloodletting therapy, low-dose aspirin anticoagulant therapy, cytoreductive therapy, and allogeneic hematopoietic stem cell transplantation (HSCT). JAK inhibitors (such as ruxolitinib) remain the basic therapeutic drugs. However, emerging strategies targeting epigenetic dysregulation and the interaction in the immune microenvironment (such as interferon-α) show promise in reducing drug resistance. New methods, including combination therapy (combination of JAK inhibitors and BCL-XL inhibitors) and mutation-independent immunotherapy, are under investigation. This review summarizes the latest advancements in the diagnosis and treatment of MPNs, highlighting the importance of molecular mechanisms in guiding therapeutic approaches and the potential for precision medicine in the future. Full article

Since its discovery, the BTK inhibitor ibrutinib has redefined the standard treatments for hematological cancers, such as chronic lymphocytic leukemia (CLL). However, concerns exist regarding its secondary effects in humans and its occasional lack of efficacy in certain malignancies. Therefore, combined therapies with ibrutinib have emerged as promising new approaches. In this study, we aimed to explore its therapeutic potential through different approaches. For this purpose, we combined this drug with the BH3 mimetics ABT-199 and ABT-737, which inhibit anti-apoptotic members of the Bcl-2 family, and with the PDK1 inhibitor dichloroacetate (DCA), respectively. As cell models, we used ex vivo samples from patients and also selected the in vitro CLL cell line Mec-1, generating two sub-lines overexpressing Bcl-XL and Mcl-1, a common feature in this cancer. Results demonstrated a synergistic effect for both approaches, in all tumor cells tested, for both cytostatic and cytotoxic effects. Mechanistically, the expression of Bcl-2-family proteins was explored, exhibiting increases in pro-apoptotic, but also in anti-apoptotic, proteins upon ibrutinib treatment and a relative increase in the amount of the pro-apoptotic protein PUMA after treatment with DCA. Our data provides new insights into combined therapies with ibrutinib for CLL, which further expands our knowledge and the potential of this drug for cancer treatment. Full article

Microbial exopolysaccharides from extreme environments are increasingly becoming valuable candidates for drug development. In this study, four fractions named XL-1, XMRS-1, XL-1-D, and XMRS-1-D were isolated and purified from the hadal bacterium Psychrobacter pulmonis by column chromatography. The structural features of these fractions were characterized by molecular weight, monosaccharide composition, Fourier transform infrared (FTIR) spectrum, amino acid analysis and NMR. The results showed that XL-1 and XMRS-1 were mainly composed of mannose, glucose, and glucosamine, while XL-1-D and XMRS-1-D were mainly composed of mannose. In vitro bioactivity assays demonstrated that all four fractions significantly enhanced RAW264.7 macrophage proliferation and phagocytosis, stimulated nitric oxide (NO) and reactive oxygen species (ROS) production, and induced the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and the expression of inducible nitric oxide synthase (iNOS) mRNA. Moreover, plate cloning tests, cell scratch tests, and apoptosis assays, along with RT-qPCR analysis, demonstrated that the four fractions significantly inhibited A549 cells’ proliferation. Specifically, XMRS-1 and XMRS-1-D upregulated Bax, Caspase-3, Caspase-8, and Caspase-9, while downregulating Bcl-2, suggesting transcriptional activation of apoptosis-related pathways. These results offered a reference for the further development and utilization of this hadal bacterium in the future. Full article

We previously developed SA-conf, a method designed to quantify backbone structural variability in protein targets. This approach is based on the HMM-SA structural alphabet, which enables efficient and rapid comparison of local backbone conformations across multiple structures of a given target. In this study, SA-conf (version for python2.7) was applied to a dataset of 130 crystallographic chains of Bcl-xL, a protein involved in promoting cell survival. SA-conf quantified and mapped backbone structural variability, revealing the protein’s capacity for conformational rearrangement. Our results showed that while most mutations had minimal impact on backbone conformation, some were associated with long-range structural effects. By jointly analyzing residue flexibility and backbone rearrangements across apo and holo structures, SA-conf identified key regions where the backbone undergoes structural adjustments upon ligand binding. Notably, the $\alpha 2$–$\alpha 3$ region was shown to be a hotspot of structural plasticity, exhibiting ligand-specific conformational signatures. Furthermore, SA-conf enabled the construction of a structural map of the binding site, distinguishing a conserved anchoring core from flexible peripheral regions that contribute to ligand specificity. Overall, this study highlights SA-conf’s capacity to detect conformational changes in protein backbones upon ligand binding and to uncover structural determinants of selective ligand recognition. Full article

Background/Objectives: Adult-type diffuse gliomas, including astrocytoma and glioblastoma multiforme (GBM), are brain tumors with a very poor prognosis. While current treatment options for glioma patients are not providing satisfactory outcomes, research indicates that natural compounds could serve as alternative treatments. However, their low bioavailability requires nanotechnology solutions, such as liposomes. Methods: In this study, we propose the co-encapsulation of acteoside (ACT) with other natural compounds, cannabidiol (CBD) or naringenin (NG), in a cationic liposomal nanoformulation consisting of DOTAP and POPC lipids, which were prepared using the dry lipid film method. The liposomes were characterized by their physicochemical properties, including particle size, zeta potential, and polydispersity index (PDI), with additional analyses performed using ¹H Nuclear Magnetic Resonance (NMR). Furthermore, biological experiments were performed with U-87 MG astrocytoma and U-138 MG GBM cell lines and non-cancerous MRC-5 lung fibroblasts using the MTT assay and evaluating the expression of Bax and Bcl-xL to evaluate their potential as anticancer agents. Conclusions: The IC₅₀ values for the nanoformulations in U-138 MG cells at 48 h were 6 µM for ACT + CBD and 5 µM for ACT + NG. ACT and CBD or NG demonstrated a potential synergistic effect against GBM in a liposomal formulation. Notably, treatment with ACT + CBD (5 µM) and ACT + NG (5 µM) liposomal formulations significantly upregulated Bax protein level in U-138 cells at both 24 and 48 h. In parallel, ACT + CBD (5 µM) also modulated Bcl-xL protein level in both U-138 MG and U-87 MG cell lines at the same time points. The obtained nanoformulations were homogeneous and stable for 21 days, evidenced by a narrow particle size distribution, a low polydispersity index (PDI) < 0.3, and a positive zeta potential. Full article

Neuroinflammation, driven by activated microglia, contributes to the progression of neurodegenerative diseases. Extracellular vesicles mediate intercellular communication and influence immune responses. Chrysin, a natural flavone found in fruits and propolis, has demonstrated anti-inflammatory effects. This study explored the immunomodulatory potential of chrysin-loaded EVs (EVs-Chry) derived from BV2 microglial cells. BV2 cells were treated with chrysin for 24 h to assess cytotoxicity and proliferation. EVs were isolated from treated and untreated cells, characterized by nanoparticle tracking analysis, and applied to naïve BV2 cells prior to LPS stimulation. Effects on cell morphology, migration, cytokine expression (IL-1β, IL-6), inflammasome activity (caspase-1), and apoptosis-related protein Bcl-xL were investigated. Our results show that EVs-Chry significantly reduced LPS-induced cell proliferation, restored resting microglial morphology, and reduced migratory capacity. Furthermore, co-treatment with EVs-Chry and LPS reduced pro-inflammatory cytokines such as IL-1β, IL-6, and caspase-1 expression while enhancing anti-apoptotic Bcl-xL levels, indicating a shift toward an anti-inflammatory, neuroprotective micro-glial phenotype. Together, our results demonstrated that EVs-Chry have neuroprotective effects on LPS-induced microglial activation and modulate microglial responses to inflammatory stimuli, attenuating pro-inflammatory signaling and promoting cellular homeostasis. These findings support the therapeutic potential of EVs-Chry in the context of neuroinflammatory and neurodegenerative disorders. Full article

Cellular senescence is a state of the durable cell cycle arrest of dysfunctional cells, which has been associated with the promotion of tumor cell reprogramming into a stem cell state. We previously reported that the mixed lineage kinase (MLK) inhibitor CEP-1347 promotes the differentiation of glioma stem cells (GSCs)—key contributors to glioblastoma recurrence and therapy resistance—into non-stem tumor cells. However, we also noted that CEP-1347–treated GSCs exhibited a morphological change suggestive of senescence. Therefore, we herein investigated whether CEP-1347 induces senescence in GSCs and, consequently, if senescent GSCs may be eliminated using senolytics. Cell death induced by CEP-1347 in combination with senolytic agents or with the knockdown of anti-apoptotic BCL2 family genes, as well as the effects of CEP-1347 on the expression of senescence markers and anti-apoptotic Bcl-2 family proteins, were examined. The results obtained showed that CEP-1347 induced senescence in GSCs accompanied by the increased expression of Bcl-xL. Among the panel of senolytic agents tested, navitoclax, a BH3 mimetic, efficiently induced cell death in GSCs when combined with CEP-1347 at concentrations clinically achievable in the brain. The knockdown of Bcl-xL resulted in more pronounced GSC death in combination with CEP-1347 than that of Bcl-2. These results suggest that combining CEP-1347 with the targeting of Bcl-xL, the expression of which increases with CEP-1347-induced senescence, is a rational approach to ensure the elimination of GSCs, thereby improving the outcomes of glioblastoma treatment. Full article

Cancers, particularly those resistant to treatment, stand as one of the most significant challenges in medicine. Frequently, available therapies need to be improved, underscoring the necessity for innovative treatment modalities. Over the years, there has been a resurgence of interest in natural plant substances, which have been traditionally overlooked as anticancer agents. A prime example of this is natural antioxidants, such as acteoside (ACT) and orientin (ORI), which offer novel approaches to cancer treatment, emphasizing liver cancer compared to other cancer types. They reduce oxidative stress by activating the Nrf2/ARE pathway and exhibit anticancer activity, e.g., decreasing Bcl-2 and Bcl-XL expression and increasing Bax levels. This review explores the individual effects of ACT and ORI and their synergistic interactions with sorafenib, temozolomide, 5-fluorouracil (for ACT), celecoxib, and curcumin (for ORI), highlighting their enhanced anticancer efficacy. In addition, ACT and ORI successfully integrate into various drug delivery systems (DDSs), including metal-containing carriers such as nanoparticles (NPs), nanoshells (NSs), quantum dots (QDs), and liposomes as representative examples of lipid-based drug delivery systems (LBDDSs). Advanced methods, including nanotechnology, offer potential solutions to low bioavailability, paving the way for the use of these substances in anticancer therapy. Full article

Current systemic therapies for advanced colorectal cancer (CRC) have limited efficacy, so more effective strategies for the treatment and prevention of CRC are needed. The majority of colorectal cancers are initiated by mutations in Wnt signalling pathway genes, including mutations in the APC gene, which result in a truncated APC protein and lead to excess signalling from β-catenin and the formation of pre-cancerous adenomas. The aim of this study was to determine if targeting the Wnt pathway in combination with pro-apoptotic mimetics altered the proliferative capacity or viability of human colorectal adenoma cells. Patient-derived colorectal adenoma organoid cultures were established from colon adenoma tissue collected by colonoscopy and recapitulated the histopathology of primary colorectal adenoma tissue. The growth of colorectal adenoma organoids is inhibited by the Wnt-signalling antagonist pyrvinium pamoate (PP) and a pro-apoptotic inhibitor of BCL-XL but not BCL-2 (venetoclax) or MCL-1 inhibitors. At low concentrations, the PP and the BCL-XL inhibitor combination demonstrated potent synergy and induced apoptosis in APC-defective patient-derived adenoma organoids, even in the presence of oncogenic KRAS or BRAF mutations, providing a new strategy for colon cancer prevention. Full article

Ovarian cancer cells overexpress HDAC6, and selective HDAC6 inhibitors have been considered potential new drugs for ovarian cancer either alone or in combination with other anticancer agents. We screened 46 potential novel HDAC6 inhibitors in ES-2 ovarian cancer cells and showed that compound 25253 demonstrated the most potent anti-proliferative activity and effective synergy with paclitaxel, which was also validated in TOV21G ovarian cancer cells. The combination of 25253 and paclitaxel significantly induced subG1 and apoptotic cells, revealed by PI staining assay and Annexin V-FITC/PI double staining assay, respectively. Western blot analysis showed downregulation of Bcl-2 and Bcl-XL, and upregulation of Bax and Bak, indicating that apoptosis was mediated through the intrinsic pathway. The combination increased γ-H2AX and p-p53 protein levels, suggesting the induction of DNA damage. Furthermore, HDAC6 was downregulated and acetylated α-tubulin was profoundly increased. Compound 25253 enhanced the inhibitory effect of paclitaxel on cell migration and invasion, possibly due to the extensive accumulation of acetylated α-tubulin, which affected microtubule dynamics. Taken together, the combination of 25253 and paclitaxel synergistically inhibited the growth, migration, and invasion of ovarian cancer cells and induced apoptosis, providing supporting evidence that the combination of HDAC6 inhibitors and paclitaxel may be a promising treatment strategy for ovarian cancer. Full article