The vacuolar proton translocating ATPase (V-ATPase) is a transmembrane multi-protein complex fundamental in maintaining a normal intracellular pH. In the tumoral contest, its role is crucial since the metabolism is mainly based on anaerobic glycolytic reactions. Moreover, the neoplastic cells use the V-ATPase to extrude chemotherapy drugs to the extra-cellular compartment, as a drug-resistance mechanism. In glioblastoma (GBM), the most malignant and incurable primary brain tumor, the expression of this pump is upregulated, making it a new possible therapeutic target. In this work, the bafilomycin A1 induced-inhibition of V-ATPase in patients-derived glioma stem cell (GSC) lines was evaluated together with temozolomide, the first-line line therapy against GBM. In contrast with previous published data, the proposed treatment did not overcome the resistance to the standard therapy. In addition, our data showed that nanomolar dosages of bafilomycin A1 lead to the blockage of the autophagy process and cellular necrosis, making the drug unusable in models that are more complex. Nevertheless, the increased expression of V-ATPase following bafilomycin A1 suggests a critical role of the proton pump in GBM stem component, encouraging the search for novel strategies to limit its activity in order to get around the resistance to the conventional therapy.

Glioblastoma is a central nervous system cancer type with a poor prognosis. One of its main features is the constant change of metabolism phenotype to support its development and progression. Mitochondria play a critical role in cellular metabolism. Acetylation on lysine residues of mitochondrial enzymes is a mechanism for regulating protein function. This modification negatively affects the mitochondrial proteome function and is counteracted by the enzyme sirtuin 3 (SIRT3). To better understand how SIRT3 regulates mitochondrial metabolism, we inhibited SIRT3 and examined by high-resolution mass spectrometry analysis the proteome and acetylome of two glioblastoma cell lines with different metabolic preferences. Our results indicate that protein synthesis machinery is regulated by lysine acetylation and plays a role in the metabolic phenotype. We also identified new SIRT3 targets not previously associated with specific functions, highlighting their potential as future targets for further study. This study shed light on the role of SIRT3 in mitochondria and its implication for cellular metabolism. We have generated knowledge at the proteome and acetylome levels on the dynamics between two glioblastoma cell lines with opposing metabolic phenotypes. Our results might guide in searching for biomarkers at both proteome and acetylome levels in glioblastoma.

Disrupted lipid metabolism is a characteristic of gliomas. This study utilizes an ultrastructural approach to characterize the prevalence and distribution of lipids within gliomas. This study made use of tissue from IDH1 wild type (IDH1-wt) glioblastoma (n=18) and IDH1 mutant (IDH1-mt) astrocytoma (n=12) tumors. We uncover a prevalent and intriguing surplus of lipids. The bulk of the lipids manifested as sizable cytoplasmic inclusions and extracellular deposits in the tumor microenvironment (TME); in some tumors the lipids were stored in the classical mem-braneless spheroidal lipid droplets (LDs). Frequently, lipids accumulated inside mitochondria, suggesting possible dysfunction of the beta-oxidation pathway. Additionally, the tumor vascula-ture are shown to have lipid deposits in their lumen and vessel walls; this lipid could have shifted in from the tumor microenvironment or have been produced by the vessel-invading tumor cells. Overproduction of lipids by the tumor is suspected to be due to a combination of two processes: i) dysfunctional oxidative phosphorylation in mitochondria that causes metabolic backup and ac-cumulation of acetyl-CoA, as well as ii) the overproduction of pyruvate due to the tumor cell reli-ance on overactive glycolysis. Tumor cells use lipids for structural components but cannot use them for energy if their oxidative phosphorylation is dysfunctional, which seems to be the case in the tumor cells we examined. This lipid-rich environment, however, offers tumor cells certain advantages: protection from the immune system, non-lipophilic drugs, and oxidative stress. Our research highlights the significant presence of lipid overproduction in both IDH1-wild type glio-blastoma and IDH1-mutant astrocytoma tumors, leading to diverse lipid accumulations in var-ious cellular compartments and structures. This lipid excess stems from disrupted beta-oxidation and dysfunctional oxidative phosphorylation pathways. The implications of this lipid-driven environment include structural support for the tumor cells and protection against immune re-sponses, non-lipophilic drugs, and free radicals.

Background: Although autophagy is a pro-survival process of tumor cells, in particular conditions and when differently regulated by specific signals it can stimulate cell death. We previously demonstrated that the selective stimulation of the M2 muscarinic receptor subtype (M2 mAChR) negatively controls cell proliferation and survival and causes oxidative stress and cytotoxic and genotoxic effects in both GBM cell lines and GBM stem cells (GSCs). In this work, we have evaluated whether autophagy was induced as a downstream mechanism of the observed cytotoxic processes induced by M2 mAChR activation by the orthosteric agonist APE or the dualsteric agonist N-8-Iper. Methods: To assess the activation of autophagy, we analyzed the expression of LC3B by Western blot analysis and in LC3B-EGFP transfected cell lines. Apoptosis was assessed by Caspases 3 and 9 protein expression. Results: Our data indicate that activation of M2 mAChR by N-8-Iper promotes autophagy in both U251 and GB7 cells lines as suggested by the LC3B-II expression level and analysis of the transfected cells by fluorescence microscopy. Autophagy induction by M2 mAChRs is regulated by the decreased activity of the PI3K/AKT/mTORC1 pathway and upregulated by the pAMPK expression. Downstream autophagy activation, the increase of apoptosis was also observed in both cell lines after treatment with the two M2 agonists. Conclusions: N-8-Iper treatment causes autophagy via pAMPK upregulation, followed by apoptosis in both investigated cell lines. In contrast, the absence of autophagy in APE-treated GSC cells seems to indicate that cell death could be triggered by mechanisms alternative to those observed for N-8-Iper.

MRI is the gold standard for treatment response assessment in glioblastoma. However, there is no consensus regarding the optimal interval for MRI follow-up during standard treatment. Moreover, reliable assessment of treatment response is hindered by the occurrence of pseudoprogression. It is unknown if a radiological follow-up strategy with 2-3 months intervals actually benefits patients and how it influences clinical decision making about continuation or discontinuation of treatment. This study assessed the consequences of scheduled follow-up scans (post-chemoradiotherapy [post-CCRT], after 3 cycles of adjuvant chemotherapy [TMZ3/6], after completion of treatment [TMZ6/6]) and unscheduled scans on treatment decisions during standard concomitant and adjuvant treatment in glioblastoma patients. Additionally, we evaluated how often follow-up scans resulted in diagnostic uncertainty (tumor progression versus pseudoprogression), and whether perfusion MRI improved clinical decision making. Scheduled follow-up scans during standard treatment in glioblastoma patients rarely resulted in early termination of treatment (2.3% post-CCRT, 3.2% TMZ3/6, and 7.8% TMZ6/6), but introduced diagnostic uncertainty in 27.7% of cases. Unscheduled scans resulted in more major treatment consequences (30%; p<0.001). Perfusion MRI caused less diagnostic uncertainty (p=0.021) but did not influence treatment consequences (p=0.871). This study does not support the current pragmatic follow-up strategy and suggests a more tailored follow-up approach.

Post-operative chemotherapy is still required for the treatment of glioblastoma (GBM), and nanocarrier-based drug delivery has been identified as one of the most effective methods. However, the blood-brain barrier (BBB) and non-specific delivery to non-tumor tissues can significantly limit drug accumulation in tumor tissues and cause damage to nearby normal tissues. This study describes a targeted cancer therapy approach that uses AS1411 aptamer-conjugated nanospheres, 100-300 nm in size, loaded with doxorubicin (Dox) to selectively identify tumor cells overexpressing nucleolin (NCL) proteins. The study demonstrates that the active target model, which employs aptamer-mediated drug delivery, is more effective than nonspecific enhanced permeability and maintenance (EPR)-mediated delivery and passive drug delivery in improving drug penetration and maintenance in tumor cells. Additionally, the study shows the potential for anticancer effects through 3D spheroidal and in vivo GBM xenograft models. The DNA-protein hybrid nanospheres utilized in this study offer numerous benefits, such as efficient synthesis, structural stability, high drug loading, dye labelling, biocompatibility, and biodegradability. When combined with nanospheres, the 1411 aptamer has been shown to be an effective drug delivery carrier for precisely targeting tumors. This combination has the potential to produce anti-tumor effects in active targeted therapy of GBM.

We previously developed a highly sensitive and specific anti-PDPN mAb, LpMab-23 (mouse IgG1, kappa). In this study, we produced a humanized IgG1 version (humLpMab-23) and its defucosylated form (humLpMab-23-f) of an anti‑PDPN mAb to potentiate the ADCC activity. The humLpMab-23 could recognize PDPN‑overexpressed Chinese hamster ovary (CHO)-K1 (CHO/PDPN) and PDPN-positive PC-10 and LN319 cells by flow cytometry. Furthermore, we found that humLpMab-23-f exerted ADCC and complement-dependent cytotoxicity against CHO/PDPN, PC-10 and LN319 cells in vitro and exhibited potent antitumor activities in the xenograft models. These results indicated that humLpMab-23-f could be useful for an antibody treatment regimen for PDPN-positive human cancers.

Glioblastoma is a highly malignant brain tumor consisting of heterogeneous cellular population. The transformed metabolism of glioblastoma cells supports their growth and division on the background of their milieu. One might hypothesize that the transformed metabolism of a primary glioblastoma could be well adapted to limitations in the variety and number of substrates imported into the brain parenchyma and present it their microenvironment. Additionally, the phenotypic heterogeneity of cancer cells could promote the variations among their metabolic capabilities regarding the utilization of available substrates and release of metabolic intermediates. With the aim to identify the putative metabolic footprint of different types of glioblastoma cells, we exploited the possibility for separation of polar and ionic molecules present in culture media or cell lysates by hydrophilic interaction liquid chromatography (HILIC). The mass spectrometry (MS) was then used to identify and quantify the eluted compounds. The introduced method allows the detection and quantification of more than 150 polar and ionic metabolites in single run, those may be present either in culture media or cell lysates and provide data for polaromic studies within metabolomics. The method was applied to analyze the culture media and cell lysates derived from two types of glioblastoma cells, T98G and U118. The analysis revealed that even the both types of glioblastoma cells share several common metabolic aspects, they also exhibit differences in their metabolic capability. This finding agrees with the hypothesis about metabolic heterogeneity of glioblastoma cells. Furthermore, the combination of both analytical methods, HILIC-MS, provides a valuable tool for metabolomic studies based on the simultaneous identification and quantification of a wide range of polar and ionic metabolites - polaromics.

Antler is the fastest growing tissue. Because is based on proto-oncogenes, to avoid the risk of cancer, antlers evolved strong anticancer mechanisms, and thus its extract (DVA) is effective also against the few human tumours studied so far. We assessed whether DVA is a general anticancer compound testing direct effects in cells of different tumours: glioblastoma (GBM), colorectal and breast cancer, and leukaemia. DVA reduced viability of tumour but not healthy cells. Mobility decreased at least at the longest test (72 h). Intraperitoneal/oral 200 mg DVA/kg administration in GBM xenograft mice for 28 d reduced tumour weight 66.3% and 61.4% respectively, and also spleen weight. In addition, tumours treated with DVA showed symptoms of liquefactive necrosis. Serum cytokines showed DVA up-regulated factors related with tumour fighting and down-regulated those related with inducing immune tolerance to the tumour. DVA shows general anticancer effects in the lines tested and, in GBM mice, also strong indirect effects apparently mediated by the immune system.

We have previously shown that the transmembrane protein ODZ1 promotes cytoskeletal remodelling of glioblastoma (GBM) cells and invasion of the surrounding parenchyma through activation of a RhoA-ROCK pathway. We also described that GBM cells can control the expression of ODZ1 through transcriptional mechanisms triggered by binding of IL-6 to its receptor and a hypoxic environment. Epidermal growth factor (EGF) plays a key role in the invasive capacity of GBM. However, the molecular mechanisms that enable tumor cells to acquire the morphological changes to migrate out from the tumor core have not been fully characterized. Here we show that EGF is able to induce the expression of ODZ1 in primary GBM cells. We analysed the levels of EGF receptor (EGFR) in 20 GBM primary cell lines and found expression in 19 of them by flow cytometry. We selected two cell lines that do or do not express EGFR and found that EGFR-expressing cells responded to EGF ligand by increasing ODZ1 at the mRNA and protein level. Moreover, blockade of EGF-EGFR binding by Cetuximab, inhibition of the p38 MAPK pathway or siRNA-mediated knockdown of MAPK11 (p38 MAPK) reduced the induction of ODZ1 in response to EGF. Overall, we show that EGF may activate an EGFR-mediated signalling pathway through p38 MAPK, to upregulate the invasion factor ODZ1, which may initiate morphological changes for tumor cells to invade the surrounding parenchyma. These data identify a new candidate of the EGF-EGFR pathway for novel therapeutic approaches.

In our study, we investigated the prognostic significance of hematological markers—NLR (Neutrophil-to-Lymphocyte Ratio), PLR (Platelet-to-Lymphocyte Ratio), and RDW-CV (Red Blood Cell Distribution Width - Coefficient of Variation)—in 117 glioblastoma patients. Data collected from January 2016 to December 2018 included demographics, clinical scores, and treatment regimens. Unlike previous research, which often examined these markers solely before surgery, our unique approach analyzed them at multiple stages: preoperative, postoperative, and before adjuvant therapies. We correlated these markers with overall survival (OS) and progression-free survival (PFS) using statistical tools, including ANOVA, Cox regression, and Kaplan-Meier survival analyses, employing SPSS version 29.0. Our findings revealed notable variations in NLR, PLR, and RDW-CV across different treatment stages. NLR and PLR decreased after surgery, with some stabilization post-STUPP phase (NLR: p=0.007, η2p=0.06; PLR: p=0.001, η2p=0.23), while RDW-CV increased post-surgery and during subsequent treatments (RDW-CV: p < 0.001, η2p=0.67). Importantly, we observed significant differences between the preoperative phase and other treatment phases. Additionally, higher NLR and RDW-CV at the second-line treatment and disease progression were associated with an increased risk of death (NLR at 2nd line: HR=1.03, p=0.029; RDW-CV at progression: HR=1.14, p=0.004). We proposed specific marker cutoffs that demonstrated significant associations with survival outcomes when applied to Kaplan-Meier survival curves (NLR at 2nd line < 5: p<0.017; RDW-CV at progression < 15: p=0.007). Elevated NLR and RDW-CV at later treatment stages correlated with poorer OS and PFS. No significant preoperative differences were detected. These biomarkers may serve as non-invasive tools for glioblastoma management.

Abstract: Abnormal growth of oligodendrocyte precursor cells (OPCs) importantly contributes to the progression of glioblastoma tumors. Hence, molecules that block OPC growth may be of therapeutic importance in treating gliomas. 2-methoxyestradiol (2ME), an endogenous tubulin interacting metabolite of estradiol is effective against multiple proliferative disorders. Based on its anti-carcinogenic and anti-angiogenic actions it is undergoing phase II clinical trials. We hy-pothesize that 2ME may prevent glioma growth by targeting OPC growth. Here we tested this hypothesis by assessing the impact of 2ME on growth of OPC cell line “Oli-neu” and dissected the underlying mechanism(s). Treatment with 2ME inhibited OPC growth in a concentra-tion-dependent manner and accompanied with significant upregulation in expression of p21 and p27, negative cell cycle regulators. Moreover, treatment with 2ME altered OPC morphology from multi-arm processes to rounded cells. At concentrations of 1uM and greater 2ME induced apoptosis with increased expression of caspase 3, PARP and caspase-7 fragments, externalized phosphatidylserine staining / apopercentage and increased mitochondrial activity. Flow-cytometry and microscopic analysis demonstrated that 2ME triggers endoreduplication in a concentration-dependent fashion. Importantly, 2ME induced cyclin E, JNK1/2 and p53 expres-sion as well as OPC cell fusion, key mechanisms driving endoreduplication or whole-genome duplication. Importantly, inhibition of p53 with pfithrin-α rescued 2ME-induced endoreduplica-tion. The pro-apoptotic and endoreduplication actions of 2ME were accompanied with upregula-tion of survivin, cyclin A, Cyclin B, Cyclin D2, ppRB. Taken together our findings provide evi-dence that 2ME not only inhibits OPC growth and triggers apoptosis, but also activates OPCs in a survival - fight or flight mode leading to endoreduplication. This inherent survival character-istic of OPCs may, in part be responsible for drug resistance in gliomas as observed for many tubulin interacting drugs. Importantly, the fate of OPCs after 2ME treatment may depend on cell-cycle status of the individual cells. Combining tubulin-interfering molecules with drugs, such as pfithrin-α, that inhibit endoreduplication may help inhibit OPC/glioma growth and lim-it drug resistance.

Glioblastoma multiforme (GBM) is one of the deadliest human cancers with very lim-ited treatment options available. The malignant behavior of GBM is manifest in a tu-mor which is highly invasive, resistant to standard cytotoxic chemotherapy and is strongly immunosuppressive. Immune checkpoint inhibitors have recently been in-troduced in the clinic and have yielded promising results in certain cancers. GBM however is largely refractory to these treatments. The immune checkpoint CD47 has recently gained attention as potential target for intervention as it conveys a “don’t eat me” signal to tumor associated macrophages via the inhibitory SIRP alpha protein. In preclinical models, administration of anti-CD47 monoclonal antibodies have shown impressive results with GBM and other tumor models. Several well characterized on-cogenic pathways have recently been shown to regulate CD47 expression in GBM cells and Glioma Stem cells (GSCs) include EGFR, beta catenin and LRIG2. Other macro-phage pathways involved in regulating phagocytosis including TREM2 and glycan binding proteins are discussed as well. Finally, Chimeric Antigen Receptor Macro-phages (CAR)-M could be leveraged for greatly enhancing phagocytosis of GBM and repolarization of the microenvironment in general. Here we comprehensively review the mechanisms that regulate about macrophage phagocytosis of GBM cells.