Glioblastoma Migration Research Articles

The LINC00957/miR-17-5p axis regulates the cell cycle and migration in glioblastoma via the cuproptosis-related gene nephronectin.

Glioblastoma (GBM) is characterized by poor prognosis and a high malignancy. The competing endogenous RNA (ceRNA) network formed by long non-coding RNA (lncRNA) and microRNA (miRNA) can regulate the incidence of GBM. Therapeutic strategies targeting cuproptosis-related genes (CRGs) have helped reduce drug resistance in patients. However, the regulatory mechanism underlying the ceRNA network related to cuproptosis in GBM remains unclear. Therefore, we aim to explore the ceRNA regulatory axis associated with cuproposis in GBM and provide a new protocol for therapy. The ceRNA network related to CRG was constructed by bioinformatics. Dual-luciferase reporter assay and other experiments were used to prove the conclusion. We found that the LINC00957/miR-17-5p axis drove nephronectin (NPNT) expression to promote the malignant progression of GBM. First, by measuring the copper ion concentration and reactive oxygen species (ROS) levels, we found that inhibiting NPNT could promote cuproptosis. Meanwhile, the results of enrichment analysis and phenotypic experiments demonstrated that the LINC00957/miR-17-5p/NPNT axis can regulate the cell cycle and migration in GBM. In terms of mechanistic evidence, findings from reporter gene experiments suggested that LINC00957 acted as a ceRNA to regulate the expression of NPNT via miR-17-5p. In addition, findings from rescue experiments confirmed that the regulation of malignant GBM progression by LINC00957 depended on NPNT to an extent. Our findings indicate that the ceRNA regulatory network is related to cuproptosis in GBM and provide novel potential targets for the diagnosis and treatment of GBM.

A covalent creatine kinase inhibitor ablates glioblastoma migration and sensitizes tumors to oxidative stress

Glioblastoma is a Grade 4 primary brain tumor defined by therapy resistance, diffuse infiltration, and near-uniform lethality. The underlying mechanisms are unknown, and no treatment has been curative. Using a recently developed creatine kinase inhibitor (CKi), we explored the role of this inhibitor on GBM biology in vitro. While CKi minimally impacted GBM cell proliferation and viability, it significantly affected migration. In established GBM cell lines and patient-derived xenografts, CKi ablated both the migration and invasion of GBM cells. CKi also hindered radiation-induced migration. RNA-seq revealed a decrease in invasion-related genes, with an unexpected increase in glutathione metabolism and ferroptosis protection genes post-CKi treatment. The effects of CKi could be reversed by the addition of cell-permeable glutathione. Carbon-13 metabolite tracing indicated heightened glutathione biosynthesis post-CKi treatment. Combinatorial CKi blockade and glutathione inhibition or ferroptosis activation abrogated cell survival. Our data demonstrated that CKi perturbs promigratory and anti-ferroptotic roles in GBM, identifying the creatine kinase axis as a druggable target for GBM treatment.

PLXDC1 serves as a potential prognostic marker and involves in malignant progression and macrophage polarization in colon cancer.

The malignant behavior and immune escape ability of cancer cells lead to therapeutic failure and poor prognosis for patients with various cancers, including colon cancer. Plexin domain containing 1 (PLXDC1) was initially identified to exert key roles in tumor by regulating angiogenesis and has recently proved to be involved in cell proliferation and migration of glioblastoma and gastric cancer cells. However, its roles in colon cancer remain unclear. In this study, the online bioinformatics databases confirmed high expression of PLXDC1 in colon cancer specimens, which was associated with cancer stages and nodal metastasis. Similarly, the increased expression of PLXDC1 was also validated in our collected samples and colon cancer cells. Moreover, patients with high expression of PLXDC1 had shorter survival, indicating that PLXDC1 might be a potential prognostic predictor for colon cancer patients. Notably, targeting PLXDC1 inhibited cancer cell viability and invasion, and enhanced cell apoptosis. Intriguingly, Tumor Immune Estimation Resource database confirmed that PLXDC1 expression was related to various tumor-infiltrating immune cells in colon adenocarcinoma including macrophages, and its expression was also correlated with M2-like macrophage markers. In vitro, colon cancer cells with PLXDC1 downregulation had a reduced ability to recruit and polarize macrophage towards M2 phenotype by decreasing the percentage of CD206+ cells and M2-like markers (CD206, CD163, arginase1, and interleukin 10 [IL-10]). Moreover, PLXDC1 knockdown attenuated M2 macrophage-mediated promotion in cancer cell viability and invasion. Mechanically, inhibition of PLXDC1 suppressed activation of the IL-6/Signal transducer and activator of transcription 3 (STAT3) signaling. Reactivating the above pathway by transfection with IL-6 plasmids reversed the suppressive effects of PLXDC1 knockdown on cancer cell malignant behaviors, macrophage recruitment and M2-like polarization. Thus, PLXDC1 downregulation may inhibit the malignancy of colon cancer cells and their ability to recruit and polarize macrophages towards M2 phenotype by blocking the IL-6/STAT3 pathway. Together, targeting PLXDC1 may attenuate the progression of colon cancer by direct roles in cancer cells and indirect roles in macrophage polarization, representing a promising therapeutic target for colon cancer patients.

Deep intravital brain tumor imaging enabled by tailored three-photon microscopy and analysis

Intravital 2P-microscopy enables the longitudinal study of brain tumor biology in superficial mouse cortex layers. Intravital microscopy of the white matter, an important route of glioblastoma invasion and recurrence, has not been feasible, due to low signal-to-noise ratios and insufficient spatiotemporal resolution. Here, we present an intravital microscopy and artificial intelligence-based analysis workflow (Deep3P) that enables longitudinal deep imaging of glioblastoma up to a depth of 1.2 mm. We find that perivascular invasion is the preferred invasion route into the corpus callosum and uncover two vascular mechanisms of glioblastoma migration in the white matter. Furthermore, we observe morphological changes after white matter infiltration, a potential basis of an imaging biomarker during early glioblastoma colonization. Taken together, Deep3P allows for a non-invasive intravital investigation of brain tumor biology and its tumor microenvironment at subcortical depths explored, opening up opportunities for studying the neuroscience of brain tumors and other model systems.

Dexmedetomidine inhibits the migration, invasion, and glycolysis of glioblastoma cells by lactylation of c-myc

ABSTRACT Background Glioblastoma (GBM) is a brain tumor with poor prognosis. Dexmedetomidine (Dex) regulates the biological behaviors of tumor cells to accelerate or decelerate cancer progression. Objective We investigated the effects of Dex on the migration, invasion, and glycolysis in GBM. Methods The concentration of Dex was determined using the cell counting kit-8 assay. The impacts of Dex on biological behaviors of GBM cells were assessed using Transwell assay, XF96 extracellular flux analysis, and western blot. The expression of c-Myc was examined using reverse transcription-quantitative polymerase chain reaction. The lactylation or stability of c-Myc was measured by western blot after immunoprecipitation or cycloheximide treatment. Results We found that Dex (200 nM) inhibited GBM cell viability, migration, invasion, and glycolysis. C-Myc was highly expressed in GBM cells and was decreased by Dex treatment. Moreover, Dex suppressed lactylated c-Myc levels via suppressing glycolysis, thereby reducing the protein stability of c-Myc. Sodium lactate treatment abrogated the effects of Dex on the biological behaviors of GBM cells. Conclusion Dex suppressed the migration, invasion, and glycolysis of GBM cells via inhibiting lactylation of c-Myc and suppressing the c-Myc stability, suggesting that Dex may be a novel therapeutic drug for GBM treatment.

Inference on an interacting diffusion system with application to in vitro glioblastoma migration (publication template).

Glioblastoma multiforme is a highly aggressive form of brain cancer, with a median survival time for diagnosed patients of 15 months. Treatment of this cancer is typically a combination of radiation, chemotherapy and surgical removal of the tumour. However, the highly invasive and diffuse nature of glioblastoma makes surgical intrusions difficult, and the diffusive properties of glioblastoma are poorly understood. In this paper, we introduce a stochastic interacting particle system as a model of in vitro glioblastoma migration, along with a maximum likelihood-algorithm designed for inference using microscopy imaging data. The inference method is evaluated on in silico simulation of cancer cell migration, and then applied to a real data set. We find that the inference method performs with a high degree of accuracy on the in silico data, and achieve promising results given the in vitro data set.

PRMT6 facilitates EZH2 protein stability by inhibiting TRAF6-mediated ubiquitination degradation to promote glioblastoma cell invasion and migration

Invasion and migration are the key hallmarks of cancer, and aggressive growth is a major factor contributing to treatment failure and poor prognosis in glioblastoma. Protein arginine methyltransferase 6 (PRMT6), as an epigenetic regulator, has been confirmed to promote the malignant proliferation of glioblastoma cells in previous studies. However, the effects of PRMT6 on glioblastoma cell invasion and migration and its underlying mechanisms remain elusive. Here, we report that PRMT6 functions as a driver element for tumor cell invasion and migration in glioblastoma. Bioinformatics analysis and glioma sample detection results demonstrated that PRMT6 is highly expressed in mesenchymal subtype or invasive gliomas, and is significantly negatively correlated with their prognosis. Inhibition of PRMT6 (using PRMT6 shRNA or inhibitor EPZ020411) reduces glioblastoma cell invasion and migration in vitro, whereas overexpression of PRMT6 produces opposite effects. Then, we identified that PRMT6 maintains the protein stability of EZH2 by inhibiting the degradation of EZH2 protein, thereby mediating the invasion and migration of glioblastoma cells. Further mechanistic investigations found that PRMT6 inhibits the transcription of TRAF6 by activating the histone methylation mark (H3R2me2a), and reducing the interaction between TRAF6 and EZH2 to enhance the protein stability of EZH2 in glioblastoma cells. Xenograft tumor assay and HE staining results showed that the expression of PRMT6 could promote the invasion of glioblastoma cells in vivo, the immunohistochemical staining results of mouse brain tissue tumor sections also confirmed the regulatory relationship between PRMT6, TRAF6, and EZH2. Our findings illustrate that PRMT6 suppresses TRAF6 transcription via H3R2me2a to enhance the protein stability of EZH2 to facilitate glioblastoma cell invasion and migration. Blocking the PRMT6-TRAF6-EZH2 axis is a promising strategy for inhibiting glioblastoma cell invasion and migration.

Reducing Brain Edema Using Berotralstat, an Inhibitor of Bradykinin, Repurposed as Treatment Adjunct in Glioblastoma

Glioblastomas synthesize, bear receptors for, and respond to bradykinin, triggering migration and proliferation. Since centrifugal migration into uninvolved surrounding brain tissue occurs early in the course of glioblastoma, this attribute defeats local treatment attempts and is the primary reason current treatments almost always fail. Stopping bradykinin-triggered migration would be a step closer to control of this disease. The recent approval and marketing of an oral plasma kallikrein inhibitor, berotralstat (Orladeyo™), and pending FDA approval of a similar drug, sebetralstat, now offers a potential method for reducing local bradykinin production at sites of bradykinin-mediated glioblastoma migration. Both drugs are approved for treating hereditary angioedema. They are ideal for repurposing as a treatment adjunct in glioblastoma. Furthermore, it has been established that peritumoral edema, a common problem during the clinical course of glioblastoma, is generated in large part by locally produced bradykinin via kallikrein action. Both brain edema and the consequent use of corticosteroids both shorten survival in glioblastoma. Therefore, by (i) migration inhibition, (ii) growth inhibition, (iii) edema reduction, and (iv) the potential for less use of corticosteroids, berotralstat may be of service in treatment of glioblastoma, slowing disease progression. This paper recounts the details and past research on bradykinin in glioblastoma and the rationale of treating it with berotralstat.

Pharmacological Modulation of the Cytosolic Oscillator Affects Glioblastoma Cell Biology

The circadian system is a conserved time-keeping machinery that regulates a wide range of processes such as sleep/wake, feeding/fasting, and activity/rest cycles to coordinate behavior and physiology. Circadian disruption can be a contributing factor in the development of metabolic diseases, inflammatory disorders, and higher risk of cancer. Glioblastoma (GBM) is a highly aggressive grade 4 brain tumor that is resistant to conventional therapies and has a poor prognosis after diagnosis, with a median survival of only 12–15 months. GBM cells kept in culture were shown to contain a functional circadian oscillator. In seeking more efficient therapies with lower side effects, we evaluated the pharmacological modulation of the circadian clock by targeting the cytosolic kinases glycogen synthase kinase-3 (GSK-3) and casein kinase 1 ε/δ (CK1ε/δ) with specific inhibitors (CHIR99021 and PF670462, respectively), the cryptochrome protein stabilizer (KL001), or circadian disruption after Per2 knockdown expression in GBM-derived cells. CHIR99021-treated cells had a significant effect on cell viability, clock protein expression, migration, and cell cycle distribution. Moreover, cultures exhibited higher levels of reactive oxygen species and alterations in lipid droplet content after GSK-3 inhibition compared to control cells. The combined treatment of CHIR99021 with temozolomide was found to improve the effect on cell viability compared to temozolomide therapy alone. Per2 disruption affected both GBM migration and cell cycle progression. Overall, our results suggest that pharmacological modulation or molecular clock disruption severely affects GBM cell biology.

S100A9, as a potential predictor of prognosis and immunotherapy response for GBM, promotes the malignant progression of GBM cells and migration of M2 macrophages.

In the past decades, the therapeutic effect of glioblastoma (GBM) has not been significantly improved. Generous evidence indicates that S100A9 has a wide range of functions in tumors, but its exploration in GBM is less. The purpose of this study is to conduct a comprehensive bioinformatics analysis and cytological experiment on S100A9 in GBM. The expression data and clinical data of GBM samples were downloaded from the public database, and comprehensive bioinformatics analysis was performed on S100A9 in GBM using R software. Wound healing assay and transwell assay were used to detect the migration activity of cells, and colony formation assay, EdU staining, and CCK-8 assay were used to detect the proliferation activity of cells. The effect of S100A9 on the migration activity of M2 macrophages was verified by the cell co-culture method. The protein expression was detected by western blotting and immunohistochemical staining. S100A9 is an independent prognostic factor in GBM patients and is related to poor prognosis. It can be used as an effective tool to predict the response of GBM patients to immune checkpoint inhibitors (ICIs). In addition, S100A9 can promote the malignant progression of GBM and the migration of M2 macrophages. On the whole, our study highlights the potential value of S100A9 in predicting prognosis and immunotherapeutic response in GBM patients. More importantly, S100A9 may promote the malignant progress of GBM by involving in some carcinogenic pathways and remodeling the tumor microenvironment (TME).

METTL1-modulated LSM14A facilitates proliferation and migration in glioblastoma via the stabilization of DDX5

Glioblastoma (GBM) is characterized by aggressive growth, invasiveness, and poor prognosis. Elucidating the molecular mechanisms underlying GBM is crucial. This study explores the role of Sm-like protein 14 homolog A (LSM14A) in GBM. Bioinformatics and clinical tissue samples analysis demonstrated that overexpression of LSM14A in GBM correlates with poorer prognosis. CCK8, EdU, colony formation, and transwell assays revealed that LSM14A promotes proliferation, migration, and invasion in GBM invitro. Invivo mouse xenograft models confirmed the results of the invitro experiments. The mechanism of LSM14A modulating GBM cell proliferation was investigated using mass spectrometry, co-immunoprecipitation (coIP), protein half-life, and methylated RNA immunoprecipitation (MeRIP) analyses. The findings indicate that during the G1/S phase, LSM14A stabilizes DDX5 in the cytoplasm, regulating CDK4 and P21 levels. Furthermore, METTL1 modulates LSM14A expression via mRNA m7G methylation. Altogether, our work highlights the METTL1-LSM14A-DDX5 pathway as a potential therapeutic target in GBM.

SRSF9 promotes cell proliferation and migration of glioblastoma through enhancing CDK1 expression

BackgroundGlioblastoma (GBM) is a highly aggressive and prevalent brain tumor that poses significant challenges in treatment. SRSF9, an RNA-binding protein, is essential for cellular processes and implicated in cancer progression. Yet, its function and mechanism in GBM need clarification.MethodsBioinformatics analysis was performed to explore differential expression of SRSF9 in GBM and its prognostic relevance to glioma patients. SRSF9 and CDK1 expression in GBM cell lines and patients’ tissues were quantified by RT-qPCR, Western blot or immunofluorescence assay. The role of SRSF9 in GBM cell proliferation and migration was assessed by MTT, Transwell and colony formation assays. Additionally, transcriptional regulation of CDK1 by SRSF9 was investigated using ChIP-PCR and dual-luciferase assays.ResultsThe elevated SRSF9 expression correlates to GBM stages and poor survival of glioma patients. Through gain-of-function and loss-of-function strategies, SRSF9 was demonstrated to promote proliferation and migration of GBM cells. Bioinformatics analysis showed that SRSF9 has an impact on cell growth pathways including cell cycle checkpoints and E2F targets. Mechanistically, SRSF9 appears to bind to the promoter of CDK1 gene and increase its transcription level, thus promoting GBM cell proliferation.ConclusionsThese findings uncover the cellular function of SRSF9 in GBM and highlight its therapeutic potential for GBM.

Cysteamine Suppresses Cancer Cell Invasion and Migration in Glioblastoma through Inhibition of Matrix Metalloproteinase Activity.

Glioblastoma (GBM) cells are highly invasive, infiltrating the surrounding normal brain tissue, thereby limiting the efficacy of surgical resection and focal radiotherapy. Cysteamine, a small aminothiol molecule that is orally bioavailable and approved for cystinosis, has potential as a cancer treatment by inhibiting tumor cell invasion and metastasis. Here we demonstrate that these potential therapeutic effects of cysteamine are likely due to the inhibition of matrix metalloproteinases (MMPs) in GBM. In vitro assays confirmed that micromolar concentrations of cysteamine were not cytotoxic, enabling the interrogation of the cellular effects without confounding tumor cell loss. Cysteamine's inhibition of MMP activity, especially the targeting of MMP2, MMP9, and MMP14, was observed at micromolar concentrations, suggesting the mechanism of action in suppressing invasion and cell migration is by inhibition of these MMPs. These findings suggest that achievable micromolar concentrations of cysteamine effectively inhibit cancer cell invasion and migration in GBM, supporting the potential for use as an adjunct cancer treatment.

The mitochondria-related gene risk mode revealed p66Shc as a prognostic mitochondria-related gene of glioblastoma.

Numerous studies have highlighted the pivotal role of mitochondria-related genes (MRGs) in the initiation and progression of glioblastoma (GBM). However, the specific contributions of MRGs coding proteins to GBM pathology remain incompletely elucidated. The identification of prognostic MRGs in GBM holds promise for the development of personalized targeted therapies and the enhancement of patient prognosis. We combined differential expression with univariate Cox regression analysis to screen prognosis-associated MRGs in GBM. Based on the nine MRGs, the hazard ratio model was conducted using a multivariate Cox regression algorithm. SHC-related survival, pathway, and immune analyses in GBM cohorts were obtained from the Biomarker Exploration of the Solid Tumor database. The proliferation and migration of U87 cells were measured by CCK-8 and transwell assay. Apoptosis in U87 cells was evaluated using flow cytometry. Confocal microscopy was employed to measure mitochondrial reactive oxygen species (ROS) levels and morphology. The expression levels of SHC1 and other relevant proteins were examined via western blotting. We screened 15 prognosis-associated MRGs and constructed a 9 MRGs-based model. Validation of the model's risk score confirmed its efficacy in predicting the prognosis of patients with GBM. Furthermore, analysis revealed that SHC1, a constituent MRG of the prognostic model, was upregulated and implicated in the progression, migration, and immune infiltration of GBM. In vitro experiments elucidated that p66Shc, the longest isoform of SHC1, modulates mitochondrial ROS production and morphology, consequently promoting the proliferation and migration of U87 cells. The 9 MRGs-based prognostic model could predict the prognosis of GBM. SHC1 was upregulated and correlated with the prognosis of patients by involvement in immune infiltration. Furthermore, in vitro experiments demonstrated that p66Shc promotes U87 cell proliferation and migration by mediating mitochondrial ROS production. Thus, p66Shc may serve as a promising biomarker and therapeutic target for GBM.

The cellular localization and oncogenic or tumor suppressive effects of angiomiotin-like protein 2 in tumor and normal cells.

Angiomiotin (AMOT) family comprises three members: AMOT, AMOT-like protein 1 (AMOTL1), and AMOT-like protein 2 (AMOTL2). AMOTL2 is widely expressed in endothelial cells, epithelial cells, and various cancer cells. Specifically, AMOTL2 predominantly localizes in the cytoplasm and nucleus in human normal cells, whereas associates with cell-cell junctions and actin cytoskeleton in non-human cells, and locates at cell junctions or within the recycling endosomes in cancer cells. AMOTL2 is implicated in regulation of tube formation, cell polarity, and shape, although the specific impact on tumorigenesis remains to be conclusively determined. It has been shown that AMOTL2 enhances tumor growth and metastasis in pancreatic, breast, and colon cancer, however inhibits cell proliferation and migration in lung, hepatocellular cancer, and glioblastoma. In addition to its role in cell shape and cytoskeletal dynamics through co-localization with F-actin, AMOTL2 modulates the transcription of Yes-associated protein (YAP) by binding to it, thereby affecting its phosphorylation and cellular sequestration. Furthermore, the stability and cellular localization of AMOTL2, influenced by its phosphorylation and ubiquitination mediated by specific proteins, affects its cellular function. Additionally, we observe that AMOTL2 is predominantly downregulated in some tumors, but significantly elevated in colorectal adenocarcinoma (COAD). Moreover, overall analysis, GSEA and ROC curve analysis indicate that AMOTL2 exerts as an oncogenic protein in COAD by modulating Wnt pathway, participating in synthesis of collagen formation, and interacting with extracellular matrix receptor. In addition, AMOTL2 potentially regulates the distribution of immune cells infiltration in COAD. In summary, AMOTL2 probably functions as an oncogene in COAD. Consequently, further in-depth mechanistic research is required to elucidate the precise roles of AMOTL2 in various cancers.

Small protein blockers of human IL-6 receptor alpha inhibit proliferation and migration of cancer cells

BackgroundInterleukin-6 (IL-6) is a multifunctional cytokine that controls the immune response, and its role has been described in the development of autoimmune diseases. Signaling via its cognate IL-6 receptor (IL-6R) complex is critical in tumor progression and, therefore, IL-6R represents an important therapeutic target.MethodsAn albumin-binding domain-derived highly complex combinatorial library was used to select IL-6R alpha (IL-6Rα)-targeted small protein binders using ribosome display. Large-scale screening of bacterial lysates of individual clones was performed using ELISA, and their IL-6Rα blocking potential was verified by competition ELISA. The binding of proteins to cells was monitored by flow cytometry and confocal microscopy on HEK293T-transfected cells, and inhibition of signaling function was examined using HEK-Blue IL-6 reporter cells. Protein binding kinetics to living cells was measured by LigandTracer, cell proliferation and toxicity by iCELLigence and Incucyte, cell migration by the scratch wound healing assay, and prediction of binding poses using molecular modeling by docking.ResultsWe demonstrated a collection of protein variants called NEF ligands, selected from an albumin-binding domain scaffold-derived combinatorial library, and showed their binding specificity to human IL-6Rα and antagonistic effect in HEK-Blue IL-6 reporter cells. The three most promising NEF108, NEF163, and NEF172 variants inhibited cell proliferation of malignant melanoma (G361 and A2058) and pancreatic (PaTu and MiaPaCa) cancer cells, and suppressed migration of malignant melanoma (A2058), pancreatic carcinoma (PaTu), and glioblastoma (GAMG) cells in vitro. The NEF binders also recognized maturation-induced IL-6Rα expression and interfered with IL-6-induced differentiation in primary human B cells.ConclusionWe report on the generation of small protein blockers of human IL-6Rα using directed evolution. NEF proteins represent a promising class of non-toxic anti-tumor agents with migrastatic potential.

PRMT6-mediated transcriptional activation of ythdf2 promotes glioblastoma migration, invasion, and emt via the wnt–β-catenin pathway

BackgroundProtein arginine methyltransferase 6 (PRMT6) plays a crucial role in various pathophysiological processes and diseases. Glioblastoma (GBM; WHO Grade 4 glioma) is the most common and lethal primary brain tumor in adults, with a prognosis that is extremely poor, despite being less common than other systemic malignancies. Our current research finds PRMT6 upregulated in GBM, enhancing tumor malignancy. Yet, the specifics of PRMT6’s regulatory processes and potential molecular mechanisms in GBM remain largely unexplored.MethodsPRMT6’s expression and prognostic significance in GBM were assessed using glioma public databases, immunohistochemistry (IHC), and immunoblotting. Scratch and Transwell assays examined GBM cell migration and invasion. Immunoblotting evaluated the expression of epithelial-mesenchymal transition (EMT) and Wnt-β-catenin pathway-related proteins. Dual-luciferase reporter assays and ChIP-qPCR assessed the regulatory relationship between PRMT6 and YTHDF2. An in situ tumor model in nude mice evaluated in vivo conditions.ResultsBioinformatics analysis indicates high expression of PRMT6 and YTHDF2 in GBM, correlating with poor prognosis. Functional experiments show PRMT6 and YTHDF2 promote GBM migration, invasion, and EMT. Mechanistic experiments reveal PRMT6 and CDK9 co-regulate YTHDF2 expression. YTHDF2 binds and promotes the degradation of negative regulators APC and GSK3β mRNA of the Wnt-β-catenin pathway, activating it and consequently enhancing GBM malignancy.ConclusionsOur results demonstrate the PRMT6-YTHDF2-Wnt-β-Catenin axis promotes GBM migration, invasion, and EMT in vitro and in vivo, potentially serving as a therapeutic target for GBM.

Abstract 2650: IGFBP2 assists EGFRvIII-positive glioblastoma to evade immune elimination

Abstract In recent years, immunotherapy has achieved significant success in the treatment of a variety of cancer types, including melanoma, non-small cell lung cancer, and colorectal cancer. However, in stark contrast, patients with glioblastoma (GBM) show remarkably poor responses to immunotherapy, failing to derive any therapeutic benefit. Thus, an understanding of the immunosuppressive microenvironment of GBM, which is considered an immunotherapy-cold tumor, is of paramount importance. One common and distinctive genetic mutation found in gliomas is that of EGFRvIII, which is linked with enhanced cell proliferation, invasion, migration, and angiogenesis in GBM. Intriguingly, we found that this mutation induced a significantly more severe immunosuppressive microenvironment compared with wild-type EGFR. To unravel the mechanisms underlying EGFRvIII mutation-induced immunosuppression in GBM, we posited that the mutant variant secretes an array of immunosuppression-related proteins into the glioma microenvironment. To investigate this, we conducted proteomic analysis of conditioned media from EGFRvIII mutant cell lines and discovered significant changes in the expression of insulin-like growth factor-binding protein-2 (IGFBP2), a well-documented oncogenic protein. Although IGFBP2 is known to be upregulated in various tumor types and is associated with malignant behaviors such as proliferation and invasion in gliomas, its role in glioma immunology remains largely unexplored. In line with our earlier bioinformatic analyses, our study revealed significant enrichment of IGFBP2 in pathways related to immunosuppression in GBM. Thus, in the present investigation, we analyzed the mechanisms by which IGFBP2 induces an immunosuppressive microenvironment. Using co-culture models, we found that IGFBP2-overexpressing glioma cells as well as glioma cells treated with exogenous IGFBP2 recruited immune cells through binding to integrin αvβ5. Furthermore, we demonstrated that IGFBP2 promoted the secretion of the classical macrophage polarization factor IL-10 by phosphorylation of STAT3. These findings indicate the significant influence of IGFBP2 in steering glioma-associated macrophages toward a pro-tumor M2-like phenotype. We also observed that IGFBP2 upregulated the expression of PD-L1 on tumor cell surfaces. These results were verified in animal experiments. Intriguingly, our preliminary data indicated that exogenous IGFBP2 translocated to the cell nucleus within hours, and immunoprecipitation assays confirmed its interaction with STAT3 in vitro. These findings collectively underscore the pivotal role of IGFBP2 in the creation of the immunosuppressive microenvironment induced by EGFRvIII mutation. Consequently, targeting IGFBP2 holds great promise for advancing immunotherapeutic approaches in EGFRvIII-mutant glioblastomas, offering an exciting avenue for potential treatments of GBM. Citation Format: Jikang Fan, Xisen Wang, Tao Li, Xuejun Yang, Wei Zhang. IGFBP2 assists EGFRvIII-positive glioblastoma to evade immune elimination [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2650.

Sanggenon C inhibits glioblastoma cell migration and invasion by promoting ubiquitination of β-catenin

Glioblastoma is a malignant and highly invasive tumor, which requires new approaches to search for chemotherapeutic agents. Sanggenon C (SC) mainly exists in the root bark of white mulberry. Although its anti-tumor effects have been reported in some cancers, the mechanism remains unclear. In this study, we used microscopic observation, transwell assay, and immunofluorescence assay to verify the effect of Sanggenon C on the migration and invasion of glioblastoma cells. We then carried out the gene set enrichment analysis (GESA), real-time qPCR assay and ubiquitination assay to delineate the molecule mechanism by which Sanggenon C affects the migration and invasion ability of glioblastoma. With the addition of Sanggenon C, glioblastoma cells were rounded up, with the migration and invasion ability weakened as verified by transwell assay and immunofluorescence assay. The results of GESA suggested that SC might regulate the expression of genes associated with migration and invasion and affect the activity of Wnt/β-catenin signaling pathway. Western blotting revealed that Sanggenon C promoted the ubiquitination of β-catenin to reduce the levels of β-catenin and its downstream proteins. This was further supported by the results of real-time qPCR analysis of target genes of β-catenin. Taken together, SC inhibits glioblastoma cell migration and invasion by enhancing β-catenin ubiquitination. Our work suggests a new direction for the treatment of glioblastoma.

Plectin plays a role in the migration and volume regulation of astrocytes: a potential biomarker of glioblastoma

BackgroundThe expression of aquaporin 4 (AQP4) and intermediate filament (IF) proteins is altered in malignant glioblastoma (GBM), yet the expression of the major IF-based cytolinker, plectin (PLEC), and its contribution to GBM migration and invasiveness, are unknown. Here, we assessed the contribution of plectin in affecting the distribution of plasmalemmal AQP4 aggregates, migratory properties, and regulation of cell volume in astrocytes.MethodsIn human GBM, the expression of glial fibrillary acidic protein (GFAP), AQP4 and PLEC transcripts was analyzed using publicly available datasets, and the colocalization of PLEC with AQP4 and with GFAP was determined by immunohistochemistry. We performed experiments on wild-type and plectin-deficient primary and immortalized mouse astrocytes, human astrocytes and permanent cell lines (U-251 MG and T98G) derived from a human malignant GBM. The expression of plectin isoforms in mouse astrocytes was assessed by quantitative real-time PCR. Transfection, immunolabeling and confocal microscopy were used to assess plectin-induced alterations in the distribution of the cytoskeleton, the influence of plectin and its isoforms on the abundance and size of plasmalemmal AQP4 aggregates, and the presence of plectin at the plasma membrane. The release of plectin from cells was measured by ELISA. The migration and dynamics of cell volume regulation of immortalized astrocytes were assessed by the wound-healing assay and calcein labeling, respectively.ResultsA positive correlation was found between plectin and AQP4 at the level of gene expression and protein localization in tumorous brain samples. Deficiency of plectin led to a decrease in the abundance and size of plasmalemmal AQP4 aggregates and altered distribution and bundling of the cytoskeleton. Astrocytes predominantly expressed P1c, P1e, and P1g plectin isoforms. The predominant plectin isoform associated with plasmalemmal AQP4 aggregates was P1c, which also affected the mobility of astrocytes most prominently. In the absence of plectin, the collective migration of astrocytes was impaired and the dynamics of cytoplasmic volume changes in peripheral cell regions decreased. Plectin’s abundance on the plasma membrane surface and its release from cells were increased in the GBM cell lines.ConclusionsPlectin affects cellular properties that contribute to the pathology of GBM. The observed increase in both cell surface and released plectin levels represents a potential biomarker and therapeutic target in the diagnostics and treatment of GBMs.