Search Results (102)

Cancer metastasis, the spread of tumour cells from the primary site to distant organs, is responsible for over 90% of cancer deaths, yet effective treatments remain elusive due to incomplete understanding of the molecular drivers involved. Podocalyxin (PODXL), a protein overexpressed in many aggressive cancers, links the cell membrane to the internal skeleton through its interaction with Ezrin, an actin cytoskeleton cross-linker. Despite its therapeutic relevance, the PODXL–Ezrin interface remains structurally uncharacterised and pharmacologically intractable. Here, we employed an integrated computational approach combining protein–protein docking, molecular dynamics (MD) simulations, and virtual screening to investigate the structural basis of the PODXL–Ezrin interaction. Using AlphaFold-predicted structures, we modelled PODXL and Ezrin complexes, revealing that PODXL’s cytoplasmic domain stabilises upon Ezrin binding, with Arg495 mediating temporally distinct electrostatic interactions essential for initial complex assembly. Particularly, we characterised the R495W missense mutation in PODXL’s Ezrin-binding domain, demonstrating that substitution of arginine with bulky, hydrophobic tryptophan may allosterically destabilise Ezrin’s dormant conformation. This mutation slightly increases the intramolecular distance between the F3 subdomain and C-terminal domain from 2.59 Å to 3.40 Å, thus leading to potential partial unmasking of the Thr567 phosphorylation site that could plausibly prime Ezrin for activation. Molecular dynamics simulations in the WT state with a total simulation time of 100 ns revealed enhanced structural rigidity and reduced radius of gyration fluctuations in the mutant complex, consistent with a potential “locked,” activation-prone state that amplifies oncogenic signalling. Through virtual screening, we identified NSC305787 as a selective destabiliser of the R495W mutant complex by disrupting key Trp495–pre-C-terminal loop Ezrin interactions and causing steric hindrance to PIP2 recruitment. Our findings identified mutation-dependent changes in drug binding that can guide the development and repurposing of compounds for targeting PODXL-related cancers and improve patient outcomes in PODXL-altered malignancies. Full article

Susac Syndrome (SuS) is a rare autoimmune neurovascular disorder characterized by sudden visual loss, hearing disturbances, and encephalopathy. Pathology affects the small vessels of the brain, retina, and inner ear. Diagnosing SuS is challenging due to its rarity, complexity, and nonspecific symptoms. This single-case study presents a proteomic analysis of tear fluid from a patient with SuS, revealing upregulated proteins involved in immune dysregulation, cytoskeletal remodeling, and cellular repair. The activation of inflammatory proteins (e.g., S100), cytoskeletal and motility-related proteins (e.g., ezrin, radixin), and membrane transport proteins (e.g., aquaporin-5, chloride intracellular channel protein), together with activation of MAPK and NF-κB signaling pathways, highlights immune dysregulation and neurovascular damage in SuS. Hyperactivation of MAPK and NF-κB pathways leads to chronic neuroinflammation and decreased expression of neutrophil defensin 1, indicating a shift from a protective to a chronic inflammatory response. These findings from the personalized proteomic pattern of SuS support the potential of tear fluid proteomics for diagnosing SuS and offer valuable insights into its underlying molecular mechanisms. Full article

Background: The aim of this study was to determine Ezrin and MMP-2 immunohistochemical expressions in the gingival tissue of patients with or without diabetes and to determine the role of the molecular pattern involvement in the evolution of periodontal disease. Material and Methods: In this histological study, we investigated 53 subjects with periodontal disease (test group—27 patients with type 2 DM; control—26 patients without diabetes). Samples from both groups were subjected to the immunohistochemistry (IHC) technique to evaluate the immunoreactivity (IR) intensity of Ezrin and MMP-2. Results: Among diabetic patients with periodontitis, 55.4% of patients exhibited intensely positive expression (+++) of Ezrin, and 44.6% of patients showed moderate expression (++) of Ezrin. All patients with diabetes and periodontitis showed intensely positive expression for MMP-2. In contrast, the control group showed negative expressions of Ezrin and MMP-2 (-) in 100% of cases. Significant statistical differences were found between Ezrin and MMP-2 expression in gingival samples of diabetic patients and non-diabetic patients with periodontal disease (p < 0.05). Conclusions: Ezrin and MMP-2 are significantly overexpressed in patients with diabetes and stage 2–3 periodontitis compared with non-diabetic patients with periodontal disease. Ezrin showed an exclusive pattern of moderate to strong positive staining in the diabetes–periodontitis group and complete absence in controls. MMP-2 displayed a broader range of staining intensities, with a predominance of strong positivity in all locations. Ezrin may represent a more consistent discriminative marker, whereas MMP-2 reflects a wider spectrum of tissue activation related to inflammation and tissue remodeling. Full article

Genetic truncation or mutation of the gene encoding band 4.1, ezrin, radixin, and moesin (FERM) domain protein containing 4A (FRMD4A) is associated with brain developmental diseases, including microcephaly with global developmental delay. It has also been identified as a risk factor for Alzheimer’s disease. By analogy with other FERM domain-containing proteins, FRMD4A is believed to regulate cell morphogenesis and/or cell polarization in central nervous system (CNS) cells; however, it remains unclear whether and how dysfunction of FRMD4A and/or its closely homologous protein FRMD4B causes abnormal morphogenesis in neuronal cells. Here, we describe for the first time the roles of FRMD4A and FRMD4B in process elongation in neuronal cells. Knockdown of Frmd4a or Frmd4b using specific RNA-targeting clustered regularly interspaced short palindromic repeat (CRISPR) and Cas13-fitted gRNAs led to decreased process elongation in primary cortical neurons. Similar decreases in neuronal marker expression were observed in the N1E-115 cell line, a model of neuronal differentiation. Furthermore, hesperetin, an aglycone of the citrus flavonoid hesperidin known to promote neuroprotective signaling, recovered the decreased process elongation induced by the knockdown of Frmd4a or Frm4b. Hesperetin also stimulated phosphorylation of mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPKs/ERKs), which could help promote neuronal processes. These results suggest that FRMD4A and FRMD4B regulate process elongation through a possible signaling pathway linked to the sustained phosphorylation of MAPKs/ERKs. Crucially, this study reveals that, at the molecular and cellular levels, hesperetin can restore normal phenotypes when FRMD4A protein or FRMD4B protein is impaired. Full article

Background: Over the last years, the phenomenon of entosis, a form of cell-in-cell structure, has been highlighted in various tumors, including poorly treatable breast or pancreatic cancers. Nevertheless, not only the biological properties, but also the molecular drivers of entosis remain unclear. Here, we evaluated SRC tyrosine kinase, a key proto-oncogene, and podoplanin (PDPN), a membrane glycoprotein, as potential regulators of entotic cell formation. Methods: In the study, two entosis-competent cell lines, BxPC-3 and MFC-7, originating from pancreatic and breast cancers, respectively, were used. SRC or PDPN genes were silenced using dedicated siRNA and the frequency of entotic structure formation was assessed using fluorescent staining and confocal imaging. Results: It was found that BxPC-3 cells deficient in PDPN are more prone to form entotic structures and that over 90% of all entotic figures formed by mixed PDPN⁺ and PDPN^- BxPC-3 cells involved PDPN-silenced cells. The SRC data supports this observation, as the suppressed entotic formation ability presented by SRC-deficient cells was linked with increased expression of PDPN. Even though the observed effects were mainly limited to BxPC-3 cells, as PDPN expression in MCF-7 cells is restricted, overall, the obtained data suggest a strong anti-entotic function of PDPN. Additionally, the performed Western blotting indicated the activation of ezrin-radixin-moesin (ERM) proteins in PDPN-deficient cells. Conclusions: Taken together, these data suggest that the negatively controlled PDPN-ERM axis may act as a molecular factor controlling the development of entotic structures and cells with naturally low PDPN expression may be more liable to form entoses. Full article

Blood units are routinely collected from adult donors and stored as packed red blood cells (PRBC). The quality of PRBC, including their deformability, decreases during storage. Since PRBC transfusion has been reported to promote circulatory issues in premature neonates (PNs), they typically receive freshly stored units. To test the hypothesis that freshly stored PRBCs can provide red blood cells (RBCs) with appropriate deformability for PN recipients, we compared the deformability of PRBCs transfused to PNs with that of cord blood RBCs (CRBCs), which are known to have deformability equivalent to that of newborn RBCs (PN-RBC). We found that, on average, CRBC deformability was higher than that of PRBCs. However, both showed significant variability with overlapping ranges. A highly significant correlation was observed between cell deformability and the combined levels of specific membrane proteins (ezrin, stomatin, flotillins) and membrane-bound hemoglobin (Pearson coefficient > 0.70, p < 0.02). This study indicates that the storage duration is inadequate for selecting PRBCs for PN recipients. PRBCs with deformability similar to that of PN-RBCs could enable safer and more effective transfusions for PN patients. Measuring membrane proteins alongside membrane-bound hemoglobin can serve as a useful method for selecting appropriate PRBC units for transfusion to PNs. Full article

The application of high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) in the analysis of peptide therapeutics demonstrates its capacity to achieve high sensitivity and selectivity, which are essential qualities for the expanding peptide therapeutic industry. Given the challenges posed by hydrophilic peptides in reversed-phase chromatography, we investigated the necessity of a derivatization procedure to improve chromatographic separation and quasimolecular ion fragmentation during MS/MS detection. We investigated how eight different derivatizing agents react with a hydrophilic lysine- and arginine-containing human ezrin peptide-1 (HEP-1) to identify the most suitable one. The results showed that the reaction of HEP-1 with propionic anhydride proceeds most rapidly and completely, providing a high and reproducible yield of the product, which has sufficient retention on the RP column. The 4-propionylated derivative of HEP-1, compared to the other derivatives considered, demonstrates the most pronounced MS/MS fragmentation. The retention time of 2.42 min allows the separation of the substance from the interfering components of the blood plasma matrix and provides a limit of quantification of 5.00 ng/mL, which allows the use of this derivatizing agent for subsequent applications in pharmacokinetic studies, and this approach can improve the analytical parameters of similar peptides in other HPLC-MS/MS studies. Full article

Prostate cancer (PCa) pathogenesis relies on intercellular communication, which can involve tunnelling nanotubes (TNTs) and extracellular vesicles (EVs). TNTs and EVs have been reported to transfer critical cargo involved in cellular functions and signalling, prompting us to investigate the extent of organelle and protein transfer in PCa cells and the potential involvement of the androgen receptor. Using live cell imaging microscopy, we observed extensive formation of TNTs and EVs operating between PCa, non-malignant, and immune cells. PCa cells were capable of transferring lysosomes, mitochondria, lipids, and endoplasmic reticulum, as well as syndecan-1, sortilin, Glut1, and Glut4. In mechanistic studies, androgen-sensitive PCa cells exhibited changes in cell morphology when stimulated by R1881 treatment. Overexpression assays of a newly designed androgen receptor (AR) plasmid revealed its novel localization in PCa cellular vesicles, which were also transferred to neighbouring cells. Selected molecular machinery, thought to be involved in intercellular communication, was investigated by knockdown studies and Western blotting/immunofluorescence/scanning electron microscopy (SEM). PCa TNTs and EVs transported proteins and organelles, which may contain specialist signalling, programming, and energy requirements that support cancer growth and progression. This makes these important intercellular communication systems ideal potential targets for therapeutic intervention. Full article

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer-related death worldwide, with no precise method for early detection. Circulating tumor cells (CTCs) expressing the dynamic polarity of the cytoskeletal membrane protein, ezrin, have been proposed to play a crucial role in tumor progression and metastasis. This study investigated the diagnostic and prognostic potential of polarized circulating tumor cells (p-CTCs) in HCC patients. CTCs were isolated from the peripheral blood of 20 HCC patients and 18 patients with nonmalignant liver disease (NMLD) via an OncoQuick^® kit and immunostained with Ezrin-Alexa Fluor 488^®, CD146-PE, and CD45-APC. A fluorescence microscopy was then performed for analysis. The HCC group exhibited significantly higher levels of p-CTCs, with median values of 0.56 p-CTCs/mL, compared to 0.02 p-CTCs/mL (p = 0.03) in the NMLD group. CTCs were detected in 95% of the HCC patients, with a sensitivity of 95% and specificity of 89%. p-CTCs were present in 75% of the HCC patients, with a sensitivity of 75% and a specificity of 94%. Higher p-CTC counts were associated with the significantly longer overall survival in HCC patients (p = 0.05). These findings suggest that p-CTCs could serve as valuable diagnostic and prognostic markers for HCC. The incorporation of p-CTCs into diagnostic strategies could enhance therapeutic decision-making and improve patient outcomes. Full article

Background: The literature reports that ezrin (EZR) is important as a linker between microfilaments and cellular environments. Moreover, it affects cancer cell migration, but the exact mechanism is not fully understood. In this study, we aimed to investigate the role of EZR in the migration of two different types of cervical cancer cells—from primary lesion (SiHa) and lymph node metastases (HT-3). In addition, we showed for the first time that a reduced EZR protein level affects the cellular response to the routinely used treatment with cisplatin. Methods: The most important stage of the study consisted of conducting a series of tests enabling the assessment of the migration potential of cervical cancer cells without altered EZR expression and with silenced protein expression. Results: Reducing the EZR level resulted in a decrease in the invasive and migration potential of SiHa and HT-3 cells’ inhibition of colony formation, a decrease in adhesive properties, and a strong reorganization of F-actin with a dominance of cells with a mitotic catastrophe phenotype. A lower level of protein significantly reduces the motor skills of SiHa and HT-3 cervical cancer cells. Conclusions: This significantly affects the assessment of EZR as a potential factor that can limit the development of metastases in targeted cancer therapy of cervical cancer. Full article

Background: Radixin is an ERM family protein that includes radixin, moesin, and ezrin. The importance of ERM family proteins has been attracting more attention, and studies on the roles of ERM in biological function and the pathogenesis of some diseases are accumulating. In particular, we have found that radixin is the most dramatically changed ERM protein in elevated glucose-treated Schwann cells. Method: We systemically review the literature on ERM, radixin in focus, and update the roles of radixin in regulating cell morphology, interaction, and cell signaling pathways. The potential of radixin as a therapeutic target in neurodegenerative diseases and cancer was also discussed. Results: Radixin research has focused on its cell functions, activation, and pathogenic roles in some diseases. Radixin and other ERM proteins maintain cell shape, growth, and motility. In the nervous system, radixin has been shown to prevent neurodegeneration and axonal growth. The activation of radixin is through phosphorylation of its conserved threonine residues. Radixin functions in cell signaling pathways by binding to membrane proteins and relaying the cell signals into the cells. Deficiency of radixin has been involved in the pathogenic process of diseases in the central nervous system and diabetic peripheral nerve injury. Moreover, radixin also plays a role in cell growth and drug resistance in multiple cancers. The trials of therapeutic potential through radixin modulation have been accumulating. However, the exact mechanisms underlying the roles of radixin are far from clarification. Conclusions: Radixin plays various roles in cells and is involved in developing neurodegenerative diseases and many types of cancers. Therefore, radixin may be considered a potential target for developing therapeutic strategies for its related diseases. Further elucidation of the function and the cell signaling pathways that are linked to radixin may open the avenue to finding novel therapeutic strategies for diseases in the nervous system and other body systems. Full article

The microtubule-disrupting agent 2-methoxyestradiol (2-ME) displays anti-tumor and anti-angiogenic properties, but its clinical development is halted due to poor pharmacokinetics. We therefore designed two 2-ME analogs in silico—an ESE-15-one and an ESE-16 one—with improved pharmacological properties. We investigated the effects of these compounds on the cytoskeleton in vitro, and their anti-angiogenic and anti-metastatic properties in ovo. Time-lapse fluorescent microscopy revealed that sub-lethal doses of the compounds disrupted microtubule dynamics. Phalloidin fluorescent staining of treated cervical (HeLa), metastatic breast (MDA-MB-231) cancer, and human umbilical vein endothelial cells (HUVECs) displayed thickened, stabilized actin stress fibers after 2 h, which rearranged into a peripheral radial pattern by 24 h. Cofilin phosphorylation and phosphorylated ezrin/radixin/moesin complexes appeared to regulate this actin response. These signaling pathways overlap with anti-angiogenic, extra-cellular communication and adhesion pathways. Sub-lethal concentrations of the compounds retarded both cellular migration and invasion. Anti-angiogenic and extra-cellular matrix signaling was evident with TIMP2 and P-VEGF receptor-2 upregulation. ESE-15-one and ESE-16 exhibited anti-tumor and anti-metastatic properties in vivo, using the chick chorioallantoic membrane assay. In conclusion, the sulfamoylated 2-ME analogs displayed promising anti-tumor, anti-metastatic, and anti-angiogenic properties. Future studies will assess the compounds for myeloproliferative effects, as seen in clinical applications of other drugs in this class. Full article

With the rapid progress in deciphering the pathogenesis of Alzheimer’s disease (AD), it has been widely accepted that the accumulation of misfolded amyloid β (Aβ) in the brain could cause the neurodegeneration in AD. Although much evidence demonstrates the neurotoxicity of Aβ, the role of Aβ in the nervous system are complex. However, more comprehensive studies are needed to understand the physiological effect of Aβ₄₀ monomers in depth. To explore the physiological mechanism of Aβ, we employed mass spectrometry to investigate the altered proteomic events induced by a lower submicromolar concentration of Aβ. Human neuroblastoma SH-SY5Y cells were exposed to five different concentrations of Aβ_1-40 monomers and collected at four time points. The proteomic analysis revealed the time–course behavior of proteins involved in biological processes, such as RNA splicing, nuclear transport and protein localization. Further biological studies indicated that Aβ₄₀ monomers may activate PI3K/AKT signaling to regulate p-Tau, Ezrin and MAP2. These three proteins are associated with dendritic morphogenesis, neuronal polarity, synaptogenesis, axon establishment and axon elongation. Moreover, Aβ₄₀ monomers may regulate their physiological forms by inhibiting the expression of BACE1 and APP via activation of the ERK1/2 pathway. A comprehensive exploration of pathological and physiological mechanisms of Aβ is beneficial for exploring novel treatment. Full article

The Ezrin/Radixin/Moesin (ERM) family of proteins act as cross-linkers between the plasma membrane and the actin cytoskeleton. This mechanism plays an essential role in processes related to membrane remodeling and organization, such as cell polarization, morphogenesis and adhesion, as well as in membrane protein trafficking and signaling pathways. For several human aquaporin (AQP) isoforms, an interaction between the ezrin band Four-point-one, Ezrin, Radixin, Moesin (FERM)-domain and the AQP C-terminus has been demonstrated, and this is believed to be important for AQP localization in the plasma membrane. Here, we investigate the structural basis for the interaction between ezrin and two human AQPs: AQP2 and AQP5. Using microscale thermophoresis, we show that full-length AQP2 and AQP5 as well as peptides corresponding to their C-termini interact with the ezrin FERM-domain with affinities in the low micromolar range. Modelling of the AQP2 and AQP5 FERM complexes using ColabFold reveals a common mode of binding in which the proximal and distal parts of the AQP C-termini bind simultaneously to distinct binding sites of FERM. While the interaction at each site closely resembles other FERM-complexes, the concurrent interaction with both sites has only been observed in the complex between moesin and its C-terminus which causes auto-inhibition. The proposed interaction between AQP2/AQP5 and FERM thus represents a novel binding mode for extrinsic ERM-interacting partners. Full article

The activation of members of the Epidermal Growth Factor Receptor (EGFR) family (including ErbB) triggers pathways that have significant effects on cellular processes and have profound consequences both in physiological and pathological conditions. Within the nervous system, the neuregulin (NRG)/ErbB3 signaling plays a crucial role in promoting the formation and maturation of excitatory synapses. Noteworthy is ErbB3, which is actively involved in the process of cerebellar lamination and myelination. All members of the ErbB-family, in particular ErbB3, have been observed within the nuclei of various cell types, including both full-length receptors and alternative variants. One of these variants was detected in Schwann cells and in glioblastoma primary cells where it showed a neuregulin-dependent expression. It binds to promoters’ chromatin associated with genes, like ezrin, involved in the formation of Ranvier’s node. Its nucleolar localization suggests that it may play a role in ribosome biogenesis and in cell proliferation. The regulation of ErbB3 expression is a complex and dynamic process that can be influenced by different factors, including miRNAs. This mechanism appears to play a significant role in glioblastoma and is often associated with a poor prognosis. Altogether, the targeting of ErbB3 has emerged as an active area of research in glioblastoma treatment. These findings highlight the underappreciated role of ErbB3 as a significant receptor that can potentially play a pivotal role in diverse pathologies, implying the existence of a shared and intricate mechanism that warrants further investigation. Full article