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| 2. |
- Caja, Laia, et al.
(author)
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The protein kinase LKB1 promotes self-renewal and blocks invasiveness in glioblastoma
- 2022
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In: Journal of Cellular Physiology. - : John Wiley & Sons. - 0021-9541 .- 1097-4652. ; 237:1, s. 743-762
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Journal article (peer-reviewed)abstract
- The role of liver kinase B1 (LKB1) in glioblastoma (GBM) development remains poorly understood. LKB1 may regulate GBM cell metabolism and has been suggested to promote glioma invasiveness. After analyzing LKB1 expression in GBM patient mRNA databases and in tumor tissue via multiparametric immunohistochemistry, we observed that LKB1 was localized and enriched in GBM tumor cells that co-expressed SOX2 and NESTIN stemness markers. Thus, LKB1-specific immunohistochemistry can potentially reveal subpopulations of stem-like cells, advancing GBM patient molecular pathology. We further analyzed the functions of LKB1 in patient-derived GBM cultures under defined serum-free conditions. Silencing of endogenous LKB1 impaired 3D-gliomasphere frequency and promoted GBM cell invasion in vitro and in the zebrafish collagenous tail after extravasation of circulating GBM cells. Moreover, loss of LKB1 function revealed mitochondrial dysfunction resulting in decreased ATP levels. Treatment with the clinically used drug metformin impaired 3D-gliomasphere formation and enhanced cytotoxicity induced by temozolomide, the primary chemotherapeutic drug against GBM. The IC50 of temozolomide in the GBM cultures was significantly decreased in the presence of metformin. This combinatorial effect was further enhanced after LKB1 silencing, which at least partially, was due to increased apoptosis. The expression of genes involved in the maintenance of tumor stemness, such as growth factors and their receptors, including members of the platelet-derived growth factor (PDGF) family, was suppressed after LKB1 silencing. The defect in gliomasphere growth caused by LKB1 silencing was bypassed after supplementing the cells with exogenous PFDGF-BB. Our data support the parallel roles of LKB1 in maintaining mitochondrial homeostasis, 3D-gliomasphere survival, and hindering migration in GBM. Thus, the natural loss of, or pharmacological interference with LKB1 function, may be associated with benefits in patient survival but could result in tumor spread.
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| 3. |
- Chisari, Andrea, et al.
(author)
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Glucose and Amino Acid Metabolic Dependencies Linked to Stemness and Metastasis in Different Aggressive Cancer Types
- 2021
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In: Frontiers in Pharmacology. - : Frontiers Media S.A.. - 1663-9812. ; 12
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Research review (peer-reviewed)abstract
- Malignant cells are commonly characterised by being capable of invading tissue, growing self-sufficiently and uncontrollably, being insensitive to apoptosis induction and controlling their environment, for example inducing angiogenesis. Amongst them, a subpopulation of cancer cells, called cancer stem cells (CSCs) shows sustained replicative potential, tumor-initiating properties and chemoresistance. These characteristics make CSCs responsible for therapy resistance, tumor relapse and growth in distant organs, causing metastatic dissemination. For these reasons, eliminating CSCs is necessary in order to achieve long-term survival of cancer patients. New insights in cancer metabolism have revealed that cellular metabolism in tumors is highly heterogeneous and that CSCs show specific metabolic traits supporting their unique functionality. Indeed, CSCs adapt differently to the deprivation of specific nutrients that represent potentially targetable vulnerabilities. This review focuses on three of the most aggressive tumor types: pancreatic ductal adenocarcinoma (PDAC), hepatocellular carcinoma (HCC) and glioblastoma (GBM). The aim is to prove whether CSCs from different tumour types share common metabolic requirements and responses to nutrient starvation, by outlining the diverse roles of glucose and amino acids within tumour cells and in the tumour microenvironment, as well as the consequences of their deprivation. Beyond their role in biosynthesis, they serve as energy sources and help maintain redox balance. In addition, glucose and amino acid derivatives contribute to immune responses linked to tumourigenesis and metastasis. Furthermore, potential metabolic liabilities are identified and discussed as targets for therapeutic intervention.
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| 4. |
- Dadras, Mahsa Shahidi, et al.
(author)
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The polarity protein Par3 coordinates positively self-renewal and negatively invasiveness in glioblastoma
- 2021
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In: Cell Death and Disease. - : Springer Nature. - 2041-4889. ; 12:10
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Journal article (peer-reviewed)abstract
- Glioblastoma (GBM) is a brain malignancy characterized by invasiveness to the surrounding brain tissue and by stem-like cells, which propagate the tumor and may also regulate invasiveness. During brain development, polarity proteins, such as Par3, regulate asymmetric cell division of neuro-glial progenitors and neurite motility. We, therefore, studied the role of the Par3 protein (encoded by PARD3) in GBM. GBM patient transcriptomic data and patient-derived culture analysis indicated diverse levels of expression of PARD3 across and independent from subtypes. Multiplex immunolocalization in GBM tumors identified Par3 protein enrichment in SOX2-, CD133-, and NESTIN-positive (stem-like) cells. Analysis of GBM cultures of the three subtypes (proneural, classical, mesenchymal), revealed decreased gliomasphere forming capacity and enhanced invasiveness upon silencing Par3. GBM cultures with suppressed Par3 showed low expression of stemness (SOX2 and NESTIN) but higher expression of differentiation (GFAP) genes. Moreover, Par3 silencing reduced the expression of a set of genes encoding mitochondrial enzymes that generate ATP. Accordingly, silencing Par3 reduced ATP production and concomitantly increased reactive oxygen species. The latter was required for the enhanced migration observed upon silencing of Par3 as anti-oxidants blocked the enhanced migration. These findings support the notion that Par3 exerts homeostatic redox control, which could limit the tumor cell-derived pool of oxygen radicals, and thereby the tumorigenicity of GBM.
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| 5. |
- Garcia-Gomez, Pedro, et al.
(author)
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NOX4 regulates TGF beta-induced proliferation and self-renewal in glioblastoma stem cells
- 2022
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In: Molecular Oncology. - : John Wiley & Sons. - 1574-7891 .- 1878-0261. ; 16:9, s. 1891-1912
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Journal article (peer-reviewed)abstract
- Y Glioblastoma (GBM) is the most aggressive and common glioma subtype, with a median survival of 15 months after diagnosis. Current treatments have limited therapeutic efficacy; thus, more effective approaches are needed. The glioblastoma tumoural mass is characterised by a small cellular subpopulation - glioblastoma stem cells (GSCs) - that has been held responsible for glioblastoma initiation, cell invasion, proliferation, relapse and resistance to chemo- and radiotherapy. Targeted therapies against GSCs are crucial, as is understanding the molecular mechanisms that govern the GSCs. Transforming growth factor beta (TGF beta) signalling and reactive oxygen species (ROS) production are known to govern and regulate cancer stem cell biology. Among the differentially expressed genes regulated by TGF beta in a transcriptomic analysis of two different patient-derived GSCs, we found NADPH oxidase 4 (NOX4) as one of the top upregulated genes. Interestingly, when patient tissues were analysed, NOX4 expression was found to be higher in GSCs versus differentiated cells. A functional analysis of the role of NOX4 downstream of TGF beta in several patient-derived GSCs showed that TGF beta does indeed induce NOX4 expression and increases ROS production in a NOX4-dependent manner. NOX4 downstream of TGF beta regulates GSC proliferation, and NOX4 expression is necessary for TGF beta-induced expression of stem cell markers and of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), which in turn controls the cell's antioxidant and metabolic responses. Interestingly, overexpression of NOX4 recapitulates the effects induced by TGF beta in GSCs: enhanced proliferation, stemness and NRF2 expression. In conclusion, this work functionally establishes NOX4 as a key mediator of GSC biology.
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| 6. |
- Gélabert, Caroline, et al.
(author)
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The long non-coding RNA LINC00707 interacts with Smad proteins to regulate TGFβ signaling and cancer cell invasion
- 2023
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In: Cell Communication and Signaling. - : BioMed Central (BMC). - 1478-811X.
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Journal article (peer-reviewed)abstract
- Background: Long non-coding RNAs (lncRNAs) regulate cellular processes by interacting with RNAs or proteins. Transforming growth factor β (TGFβ) signaling via Smad proteins regulates gene networks that control diverse biological processes, including cancer cell migration. LncRNAs have emerged as TGFβ targets, yet, their mechanism of action and biological role in cancer remains poorly understood.Methods: Whole-genome transcriptomics identified lncRNA genes regulated by TGFβ. Protein kinase inhibitors and RNA-silencing, in combination with cDNA cloning, provided loss- and gain-of-function analyses. Cancer cell-based assays coupled to RNA-immunoprecipitation and protein screening sought mechanistic evidence. Functional validation of TGFβ-regulated lncRNAs was based on new transcriptomics and by combining RNAscope with immunohistochemical analysis in tumor tissue.Results: Transcriptomics of TGFβ signaling responses revealed down-regulation of the predominantly cytoplasmic long intergenic non-protein coding RNA 707 (LINC00707). Expression of LINC00707 required Smad and mitogen-activated protein kinase inputs. By limiting the binding of Krüppel-like factor 6 to the LINC00707 promoter, TGFβ led to LINC00707 repression. Functionally, LINC00707 suppressed cancer cell invasion, as well as key fibrogenic and pro-mesenchymal responses to TGFβ, as also attested by RNA-sequencing analysis. LINC00707 also suppressed Smad-dependent signaling. Mechanistically, LINC00707 interacted with and retained Smad proteins in the cytoplasm. Upon TGFβ stimulation, LINC00707 elimination allowed Smad accumulation in the nucleus. In vivo, LINC00707 expression was negatively correlated with Smad2 activation in tumor tissues.Conclusions: TGFβ signaling decreases LINC00707 expression, which facilitates Smad-dependent signaling, favoring cancer cell invasion.
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| 7. |
- Golan, Irene, et al.
(author)
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The TGF-β Family in Glioblastoma
- 2024
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In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 25:2
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Research review (peer-reviewed)abstract
- Members of the transforming growth factor beta (TGF-beta) family have been implicated in the biology of several cancers. In this review, we focus on the role of TGF beta and bone morphogenetic protein (BMP) signaling in glioblastoma. Glioblastoma (GBM) is the most common malignant brain tumor in adults; it presents at a median age of 64 years, but can occur at any age, including childhood. Unfortunately, there is no cure, and even patients undergoing current treatments (surgical resection, radiotherapy, and chemotherapy) have a median survival of 15 months. There is a great need to identify new therapeutic targets to improve the treatment of GBM patients. TGF-beta s signaling promotes tumorigenesis in glioblastoma, while BMPs suppress tumorigenic potential by inducing tumor cell differentiation. In this review, we discuss the actions of TGF-beta s and BMPs on cancer cells as well as in the tumor microenvironment, and their use in potential therapeutic intervention.
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| 8. |
- Martin-Rubio, Paula, et al.
(author)
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Metabolic determinants of stemness in medulloblastoma
- 2022
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In: World Journal of Stem Cells. - : BAISHIDENG PUBLISHING GROUP INC. - 1948-0210. ; 14:8, s. 587-598
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Research review (peer-reviewed)abstract
- Medulloblastomas (MBs) are the most prevalent brain tumours in children. They are classified as grade IV, the highest in malignancy, with about 30% metastatic tumours at the time of diagnosis. Cancer stem cells (CSCs) are a small subset of tumour cells that can initiate and support tumour growth. In MB, CSCs contribute to tumour initiation, metastasis, and therapy resistance. Metabolic differences among the different MB groups have started to emerge. Sonic hedgehog tumours show enriched lipid and nucleic acid metabolism pathways, whereas Group 3 MBs upregulate glycolysis, gluconeogenesis, glutamine anabolism, and glut athione-mediated anti-oxidant pathways. Such differences impact the clinical behaviour of MB tumours and can be exploited therapeutically. In this review, we summarise the existing knowledge about metabolic rewiring in MB, with a particular focus on MB-CSCs. Finally, we highlight some of the emerging metabolism-based therapeutic strategies for MB.
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| 9. |
- Mendes Rodrigues Junior, Dorival, et al.
(author)
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Aporphine and isoquinoline derivatives block glioblastoma cell stemness and enhance temozolomide cytotoxicity
- 2022
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1, s. 21113-
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Journal article (peer-reviewed)abstract
- Glioblastoma (GBM) is the most aggressive and common primary malignant brain tumor with limited available therapeutic approaches. Despite improvements in therapeutic options for GBM patients, efforts to develop new successful strategies remain as major unmet medical needs. Based on the cytotoxic properties of aporphine compounds, we evaluated the biological effect of 12 compounds obtained through total synthesis of ( ±)-apomorphine hydrochloride (APO) against GBM cells. The compounds 2,2,2-trifluoro-1-(1-methylene-3,4-dihydroisoquinolin-2(1H)-yl)ethenone (A5) and ( ±)-1-(10,11-dimethoxy-6a,7-dihydro-4H-dibenzo[de,g]quinolin-6(5H)-yl)ethenone (C1) reduced the viability of GBM cells, with 50% inhibitory concentration ranging from 18 to 48 μM in patient-derived GBM cultures. Our data show that APO, A5 or C1 modulate the expression of DNA damage and apoptotic markers, impair 3D-gliomasphere growth and reduce the expression of stemness markers. Potential activity and protein targets of A5, C1 or APO were predicted in silico based on PASS and SEA software. Dopamine receptors (DRD1 and 5), CYP2B6, CYP2C9 and ABCB1, whose transcripts were differentially expressed in the GBM cells, were among the potential A5 or C1 target proteins. Docking analyses (HQSAR and 3D-QSAR) were performed to characterize possible interactions of ABCB1 and CYP2C9 with the compounds. Notably, A5 or C1 treatment, but not temozolomide (TMZ), reduced significantly the levels of extracellular ATP, suggesting ABCB1 negative regulation, which was correlated with stronger cytotoxicity induced by the combination of TMZ with A5 or C1 on GBM cells. Hence, our data reveal a potential therapeutic application of A5 and C1 as cytotoxic agents against GBM cells and predicted molecular networks that can be further exploited to characterize the pharmacological effects of these isoquinoline-containing substances.
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| 10. |
- Papoutsoglou, Panagiotis, et al.
(author)
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The noncoding MIR100HG RNA enhances the autocrine function of transforming growth factor beta signaling
- 2021
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In: Oncogene. - : Springer Nature. - 0950-9232 .- 1476-5594. ; 40:21, s. 3748-3765
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Journal article (peer-reviewed)abstract
- Activation of the transforming growth factor beta (TGF beta) pathway modulates the expression of genes involved in cell growth arrest, motility, and embryogenesis. An expression screen for long noncoding RNAs indicated that TGF beta induced mir-100-let-7a-2-mir-125b-1 cluster host gene (MIR100HG) expression in diverse cancer types, thus confirming an earlier demonstration of TGF beta-mediated transcriptional induction of MIR100HG in pancreatic adenocarcinoma. MIR100HG depletion attenuated TGF beta signaling, expression of TGF beta-target genes, and TGF beta-mediated cell cycle arrest. Moreover, MIR100HG silencing inhibited both normal and cancer cell motility and enhanced the cytotoxicity of cytostatic drugs. MIR100HG overexpression had an inverse impact on TGF beta signaling responses. Screening for downstream effectors of MIR100HG identified the ligand TGF beta 1. MIR100HG and TGFB1 mRNA formed ribonucleoprotein complexes with the RNA-binding protein HuR, promoting TGF beta 1 cytokine secretion. In addition, TGF beta regulated let-7a-2-3p, miR-125b-5p, and miR-125b-1-3p expression, all encoded by MIR100HG intron-3. Certain intron-3 miRNAs may be involved in TGF beta/SMAD-mediated responses (let-7a-2-3p) and others (miR-100, miR-125b) in resistance to cytotoxic drugs mediated by MIR100HG. In support of a model whereby TGF beta induces MIR100HG, which then enhances TGF beta 1 secretion, analysis of human carcinomas showed that MIR100HG expression correlated with expression of TGFB1 and its downstream extracellular target TGFBI. Thus, MIR100HG controls the magnitude of TGF beta signaling via TGF beta 1 autoinduction and secretion in carcinomas.
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