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1.
Cell Death Dis ; 15(5): 306, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38693105

RESUMO

Colorectal cancers (CRCs) are highly heterogeneous and show a hierarchical organization, with cancer stem cells (CSCs) responsible for tumor development, maintenance, and drug resistance. Our previous studies showed the importance of thyroid hormone-dependent signaling on intestinal tumor development and progression through action on stem cells. These results have a translational value, given that the thyroid hormone nuclear receptor TRα1 is upregulated in human CRCs, including in the molecular subtypes associated with CSC features. We used an established spheroid model generated from the human colon adenocarcinoma cell line Caco2 to study the effects of T3 and TRα1 on spheroid formation, growth, and response to conventional chemotherapies. Our results show that T3 treatment and/or increased TRα1 expression in spheroids impaired the response to FOLFIRI and conferred a survival advantage. This was achieved by stimulating drug detoxification pathways and increasing ALDH1A1-expressing cells, including CSCs, within spheroids. These results suggest that clinical evaluation of the thyroid axis and assessing TRα1 levels in CRCs could help to select optimal therapeutic regimens for patients with CRC. Proposed mechanism of action of T3/TRα1 in colon cancer spheroids. In the control condition, TRα1 participates in maintaining homeostatic cell conditions. The presence of T3 in the culture medium activates TRα1 action on target genes, including the drug efflux pumps ABCG2 and ABCB1. In the case of chemotherapy FOLFIRI, the increased expression of ABC transcripts and proteins induced by T3 treatment is responsible for the augmented efflux of 5-FU and Irinotecan from the cancer cells. Taken together, these mechanisms contribute to the decreased efficacy of the chemotherapy and allow cells to escape the treatment. Created with BioRender.com .


Assuntos
Camptotecina/análogos & derivados , Neoplasias do Colo , Fluoruracila , Células-Tronco Neoplásicas , Esferoides Celulares , Receptores alfa dos Hormônios Tireóideos , Tri-Iodotironina , Humanos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Receptores alfa dos Hormônios Tireóideos/metabolismo , Receptores alfa dos Hormônios Tireóideos/genética , Células CACO-2 , Neoplasias do Colo/metabolismo , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/patologia , Neoplasias do Colo/genética , Esferoides Celulares/efeitos dos fármacos , Esferoides Celulares/metabolismo , Esferoides Celulares/patologia , Tri-Iodotironina/farmacologia , Leucovorina/farmacologia , Leucovorina/uso terapêutico , Camptotecina/farmacologia , Camptotecina/uso terapêutico , Fenótipo , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Família Aldeído Desidrogenase 1/metabolismo , Família Aldeído Desidrogenase 1/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Retinal Desidrogenase/metabolismo , Retinal Desidrogenase/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética
2.
bioRxiv ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38585848

RESUMO

RNA binding proteins (RBPs) containing intrinsically disordered regions (IDRs) are present in diverse molecular complexes where they function as dynamic regulators. Their characteristics promote liquid-liquid phase separation (LLPS) and the formation of membraneless organelles such as stress granules and nucleoli. IDR-RBPs are particularly relevant in the nervous system and their dysfunction is associated with neurodegenerative diseases and brain tumor development. SERBP1 is a unique member of this group, being mostly disordered and lacking canonical RNA-binding domains. Using a proteomics approach followed by functional analysis, we defined SERBP1's interactome. We uncovered novel SERBP1 roles in splicing, cell division, and ribosomal biogenesis and showed its participation in pathological stress granules and Tau aggregates in Alzheimer's disease brains. SERBP1 preferentially interacts with other G-quadruplex (G4) binders, implicated in different stages of gene expression, suggesting that G4 binding is a critical component of SERBP1 function in different settings. Similarly, we identified important associations between SERBP1 and PARP1/polyADP-ribosylation (PARylation). SERBP1 interacts with PARP1 and its associated factors and influences PARylation. Moreover, protein complexes in which SERBP1 participates contain mostly PARylated proteins and PAR binders. Based on these results, we propose a feedback regulatory model in which SERBP1 influences PARP1 function and PARylation, while PARylation modulates SERBP1 functions and participation in regulatory complexes.

4.
RNA Biol ; 20(1): 311-322, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-37294214

RESUMO

The exon junction complex (EJC) plays key roles throughout the lifespan of RNA and is particularly relevant in the nervous system. We investigated the roles of two EJC members, the paralogs MAGOH and MAGOHB, with respect to brain tumour development. High MAGOH/MAGOHB expression was observed in 14 tumour types; glioblastoma (GBM) showed the greatest difference compared to normal tissue. Increased MAGOH/MAGOHB expression was associated with poor prognosis in glioma patients, while knockdown of MAGOH/MAGOHB affected different cancer phenotypes. Reduced MAGOH/MAGOHB expression in GBM cells caused alterations in the splicing profile, including re-splicing and skipping of multiple exons. The binding profiles of EJC proteins indicated that exons affected by MAGOH/MAGOHB knockdown accumulated fewer complexes on average, providing a possible explanation for their sensitivity to MAGOH/MAGOHB knockdown. Transcripts (genes) showing alterations in the splicing profile are mainly implicated in cell division, cell cycle, splicing, and translation. We propose that high MAGOH/MAGOHB levels are required to safeguard the splicing of genes in high demand in scenarios requiring increased cell proliferation (brain development and GBM growth), ensuring efficient cell division, cell cycle regulation, and gene expression (splicing and translation). Since differentiated neuronal cells do not require increased MAGOH/MAGOHB expression, targeting these paralogs is a potential option for treating GBM.


Assuntos
Genes cdc , Glioblastoma , Humanos , Splicing de RNA , Divisão Celular , Núcleo Celular/metabolismo , Glioblastoma/metabolismo , Proteínas Nucleares/metabolismo
5.
Neuro Oncol ; 25(3): 459-470, 2023 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35862252

RESUMO

BACKGROUND: The loss of neurogenic tumor suppressor microRNAs miR-124, miR-128, and miR-137 is associated with glioblastoma's undifferentiated state. Most of their impact comes via the repression of a network of oncogenic transcription factors. We conducted a high-throughput functional siRNA screen in glioblastoma cells and identify E74 like ETS transcription factor 4 (ELF4) as the leading contributor to oncogenic phenotypes. METHODS: In vitro and in vivo assays were used to assess ELF4 impact on cancer phenotypes. We characterized ELF4's mechanism of action via genomic and lipidomic analyses. A MAPK reporter assay verified ELF4's impact on MAPK signaling, and qRT-PCR and western blotting were used to corroborate ELF4 regulatory role on most relevant target genes. RESULTS: ELF4 knockdown resulted in significant proliferation delay and apoptosis in GBM cells and long-term growth delay and morphological changes in glioma stem cells (GSCs). Transcriptomic analyses revealed that ELF4 controls two interlinked pathways: 1) Receptor tyrosine kinase signaling and 2) Lipid dynamics. ELF4 modulation directly affected receptor tyrosine kinase (RTK) signaling, as mitogen-activated protein kinase (MAPK) activity was dependent upon ELF4 levels. Furthermore, shotgun lipidomics revealed that ELF4 depletion disrupted several phospholipid classes, highlighting ELF4's importance in lipid homeostasis. CONCLUSIONS: We found that ELF4 is critical for the GBM cell identity by controlling genes of two dependent pathways: RTK signaling (SRC, PTK2B, and TNK2) and lipid dynamics (LRP1, APOE, ABCA7, PLA2G6, and PITPNM2). Our data suggest that targeting these two pathways simultaneously may be therapeutically beneficial to GBM patients.


Assuntos
Neoplasias Encefálicas , Glioblastoma , MicroRNAs , Humanos , Fatores de Transcrição/genética , Glioblastoma/patologia , MicroRNAs/genética , Receptores Proteína Tirosina Quinases/genética , Regulação Neoplásica da Expressão Gênica , Lipídeos , Proliferação de Células , Linhagem Celular Tumoral , Neoplasias Encefálicas/patologia , Proteínas de Ligação a DNA/genética , Proteínas Tirosina Quinases/metabolismo
6.
Front Mol Biosci ; 8: 744707, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34631798

RESUMO

RNA binding proteins (RBPs) are essential for critical biological processes such as translation regulation and mRNA processing, and misfunctions of these proteins are associated with diseases such as cancer and neurodegeneration. SERBP1 (SERPINE1 mRNA Binding Protein 1) is an RBP that comprises two RG/RGG repeat regions yet lacks other recognizable RNA-binding motifs. It is involved in mRNA maturation, and translational regulation. It was initially identified as a hyaluronic acid binding protein, but recent studies have identified central roles for SERBP1 in brain function and development, especially neurogenesis and synaptogenesis. SERBP1 regulates One-carbon metabolism and epigenetic modification of histones, and increased SERBP1 expression in cancers such as leukemia, ovarian, prostate, liver and glioblastoma is correlated with poor patient outcomes. Despite these important regulatory roles for SERBP1, little is known about its structural and dynamic properties, nor about the molecular mechanisms governing its interaction with mRNA. Here, we define SERBP1 as an intrinsically disordered protein, containing highly conserved elements that were shown to be functionally important. The RNA binding activity of SERBP1 was explored using solution NMR and other biophysical techniques. The outcome of these experiments revealed that SERBP1 preferentially samples compact conformations including a central, stable α-helix and show that SERBP1 recognizes G-rich RNA sequences at the C-terminus involving the RGG box and neighboring residues. Despite the role in RNA recognition, the RGG boxes do not seem to stabilize the central helix and the central helix does not participate in RNA binding. Further, SERBP1 undergoes liquid-liquid phase separation, mediated by salt and RNA, and both RGG boxes are necessary for the efficient formation of condensed phases. Together, these results provide a foundation for understanding the molecular mechanisms of SERBP1 functions in physiological and pathological processes.

7.
Acta Neuropathol Commun ; 9(1): 101, 2021 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-34059134

RESUMO

Glioblastoma (GBM) displays marked cellular and metabolic heterogeneity that varies among cellular microenvironments within a tumor. Metabolic targeting has long been advocated as a therapy against many tumors including GBM, but how lipid metabolism is altered to suit different microenvironmental conditions and whether cancer stem cells (CSCs) have altered lipid metabolism are outstanding questions in the field. We interrogated gene expression in separate microenvironments of GBM organoid models that mimic the transition between nutrient-rich and nutrient-poor pseudopalisading/perinecrotic tumor zones using spatial-capture RNA-sequencing. We revealed a striking difference in lipid processing gene expression and total lipid content between diverse cell populations from the same patient, with lipid enrichment in hypoxic organoid cores and also in perinecrotic and pseudopalisading regions of primary patient tumors. This was accompanied by regionally restricted upregulation of hypoxia-inducible lipid droplet-associated (HILPDA) gene expression in organoid cores and pseudopalisading regions of clinical GBM specimens, but not lower-grade brain tumors. CSCs have low lipid droplet accumulation compared to non-CSCs in organoid models and xenograft tumors, and prospectively sorted lipid-low GBM cells are functionally enriched for stem cell activity. Targeted lipidomic analysis of multiple patient-derived models revealed a significant shift in lipid metabolism between GBM CSCs and non-CSCs, suggesting that lipid levels may not be simply a product of the microenvironment but also may be a reflection of cellular state. CSCs had decreased levels of major classes of neutral lipids compared to non-CSCs, but had significantly increased polyunsaturated fatty acid production due to high fatty acid desaturase (FADS1/2) expression which was essential to maintain CSC viability and self-renewal. Our data demonstrate spatially and hierarchically distinct lipid metabolism phenotypes occur clinically in the majority of patients, can be recapitulated in laboratory models, and may represent therapeutic targets for GBM.


Assuntos
Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Metabolismo dos Lipídeos/fisiologia , Células-Tronco Neoplásicas/metabolismo , Organoides/metabolismo , Microambiente Tumoral/fisiologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Células-Tronco Neoplásicas/patologia , Organoides/patologia , Células Tumorais Cultivadas
8.
Cancers (Basel) ; 13(7)2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33804958

RESUMO

RNA-binding proteins (RBPs) function as master regulators of gene expression. Alterations in their levels are often observed in tumors with numerous oncogenic RBPs identified in recent years. Musashi1 (Msi1) is an RBP and stem cell gene that controls the balance between self-renewal and differentiation. High Msi1 levels have been observed in multiple tumors including glioblastoma and are often associated with poor patient outcomes and tumor growth. A comprehensive genomic analysis identified a network of cell cycle/division and DNA replication genes and established these processes as Msi1's core regulatory functions in glioblastoma. Msi1 controls this gene network via two mechanisms: direct interaction and indirect regulation mediated by the transcription factors E2F2 and E2F8. Moreover, glioblastoma lines with Msi1 knockout (KO) displayed increased sensitivity to cell cycle and DNA replication inhibitors. Our results suggest that a drug combination strategy (Msi1 + cell cycle/DNA replication inhibitors) could be a viable route to treat glioblastoma.

9.
Development ; 148(8)2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33757992

RESUMO

The thyroid hormone T3 and its nuclear receptor TRα1 control gut development and homeostasis through the modulation of intestinal crypt cell proliferation. Despite increasing data, in-depth analysis on their specific action on intestinal stem cells is lacking. By using ex vivo 3D organoid cultures and molecular approaches, we observed early responses to T3 involving the T3-metabolizing enzyme Dio1 and the transporter Mct10, accompanied by a complex response of stem cell- and progenitor-enriched genes. Interestingly, specific TRα1 loss-of-function (inducible or constitutive) was responsible for low ex vivo organoid development and impaired stem cell activity. T3 treatment of animals in vivo not only confirmed the positive action of this hormone on crypt cell proliferation but also demonstrated its key action in modulating the number of stem cells, the expression of their specific markers and the commitment of progenitors into lineage-specific differentiation. In conclusion, T3 treatment or TRα1 modulation has a rapid and strong effect on intestinal stem cells, broadening our perspectives in the study of T3/TRα1-dependent signaling in these cells.


Assuntos
Proliferação de Células , Intestinos , Transdução de Sinais , Células-Tronco/metabolismo , Receptores alfa dos Hormônios Tireóideos/metabolismo , Tri-Iodotironina/metabolismo , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Animais , Feminino , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Células-Tronco/citologia , Receptores alfa dos Hormônios Tireóideos/genética , Tri-Iodotironina/genética
10.
Cancer Res ; 81(10): 2730-2744, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33741693

RESUMO

Intestinal crypts are composed of heterogeneous and highly plastic cell populations. Lgr5high-stem cells (SC) are responsible for homeostatic renewal, but other cells can revert to an SC-like phenotype to maintain epithelial integrity. Despite their distinct roles in orchestrating homeostasis, both populations have been designated as the putative "cell-of-origin" of colorectal cancer. However, their respective involvement in the emergence of drug-resistant cancer SCs (CSC), responsible for tumor relapse and associated with poor outcome of colorectal cancer, remains elusive. In this context, the intestinal SC/progenitor-marker Musashi1 (MSI1) is interesting as it plays important functions in intestinal homeostasis and is frequently overexpressed in human colorectal cancer. Therefore, our aims were: (i) to study the impact of chemotherapy on Lgr5-expressing and MSI1-expressing cell populations, (ii) to explore the effect of increased MSI1 levels in response to treatment, and (iii) to evaluate the relevance in human colorectal cancer. Engineered mouse models treated with the therapeutic agent 5-fluorouracil showed that upon increased MSI1 levels, Lgr5high SCs remain sensitive while Lgr5low progenitors reprogram to a drug-resistant phenotype. This resulted in the expansion of an MSI1-expressing cell subpopulation with improved resistance to DNA damage and increased detoxification, typical properties of dormant-CSCs that can reactivate after chemotherapy. Analysis in patients with colorectal cancer revealed a correlation between MSI1 levels and tumor grading, CSC phenotype, and chemoresistance. Altogether, these results shed new light on the biology and plasticity of normal crypt and cancer cell populations and also open new perspectives to target MSI1 to improve chemotherapy outcome. SIGNIFICANCE: This study unveils paradoxical roles for MSI1, underlining its importance in facilitating intestinal regeneration upon injury but also unraveling its new function in drug-resistant colorectal cancer stem cells.


Assuntos
Neoplasias Colorretais/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Fluoruracila/farmacologia , Mucosa Intestinal/efeitos dos fármacos , Células-Tronco Neoplásicas/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Proteínas de Ligação a RNA/metabolismo , Receptores Acoplados a Proteínas G/fisiologia , Animais , Antimetabólitos Antineoplásicos/farmacologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Modelos Animais de Doenças , Feminino , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Proteínas do Tecido Nervoso/genética , Fenótipo , Proteínas de Ligação a RNA/genética
11.
Cancers (Basel) ; 13(2)2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33466745

RESUMO

Tumor suppressor microRNAs (miRNAs) have been explored as agents to target cancer stem cells. Most strategies use a single miRNA mimic and present many disadvantages, such as the amount of reagent required and the diluted effect on target genes. miRNAs work in a cooperative fashion to regulate distinct biological processes and pathways. Therefore, we propose that miRNA combinations could provide more efficient ways to target cancer stem cells. We have previously shown that miR-124, miR-128, and miR-137 function synergistically to regulate neurogenesis. We used a combination of these three miRNAs to treat glioma stem cells and showed that this treatment was much more effective than single miRNAs in disrupting cell proliferation and survival and promoting differentiation and response to radiation. Transcriptomic analyses indicated that transcription regulation, angiogenesis, metabolism, and neuronal differentiation are among the main biological processes affected by transfection of this miRNA combination. In conclusion, we demonstrated the value of using combinations of neurogenic miRNAs to disrupt cancer phenotypes and glioma stem cell growth. The synergistic effect of these three miRNA amplified the repression of oncogenic factors and the effect on cancer relevant pathways. Future therapeutic approaches would benefit from utilizing miRNA combinations, especially when targeting cancer-initiating cell populations.

12.
Cells ; 11(1)2021 12 25.
Artigo em Inglês | MEDLINE | ID: mdl-35011618

RESUMO

Medulloblastoma is the most common malignant brain tumor in children. Treatment with surgery, irradiation, and chemotherapy has improved survival in recent years, but patients are frequently left with devastating neurocognitive and other sequelae. Patients in molecular subgroups 3 and 4 still experience a high mortality rate. To identify new pathways contributing to medulloblastoma development and create new routes for therapy, we have been studying oncogenic RNA-binding proteins. We defined Musashi1 (Msi1) as one of the main drivers of medulloblastoma development. The high expression of Msi1 is prevalent in Group 4 and correlates with poor prognosis while its knockdown disrupted cancer-relevant phenotypes. Genomic analyses (RNA-seq and RIP-seq) indicated that cell cycle and division are the main biological categories regulated by Msi1 in Group 4 medulloblastoma. The most prominent Msi1 targets include CDK2, CDK6, CCND1, CDKN2A, and CCNA1. The inhibition of Msi1 with luteolin affected the growth of CHLA-01 and CHLA-01R Group 4 medulloblastoma cells and a synergistic effect was observed when luteolin and the mitosis inhibitor, vincristine, were combined. These findings indicate that a combined therapeutic strategy (Msi1 + cell cycle/division inhibitors) could work as an alternative to treat Group 4 medulloblastoma.


Assuntos
Ciclo Celular/genética , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Regulação Neoplásica da Expressão Gênica , Meduloblastoma/genética , Meduloblastoma/patologia , Proteínas do Tecido Nervoso/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Redes Reguladoras de Genes/efeitos dos fármacos , Humanos , Luteolina/farmacologia , Morfogênese/efeitos dos fármacos , Morfogênese/genética , Fenótipo , Prognóstico , Vincristina/farmacologia , Quinases da Família src/metabolismo
13.
Cancers (Basel) ; 12(12)2020 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-33291443

RESUMO

The stem cell marker Musashi1 (MSI1) is highly expressed during neurogenesis and in glioblastoma (GBM). MSI1 promotes self-renewal and impairs differentiation in cancer and non-malignant progenitor cells. However, a comprehensive understanding of its role in promoting GBM-driving networks remains to be deciphered. We demonstrate that MSI1 is highly expressed in GBM recurrences, an oncologist's major defiance. For the first time, we provide evidence that MSI1 promotes the expression of stem cell markers like CD44, co-expressed with MSI1 within recurrence-promoting cells at the migrating front of primary GBM samples. With GBM cell models of pediatric and adult origin, including isolated primary tumorspheres, we show that MSI1 promotes stem cell-like characteristics. Importantly, it impairs CD44 downregulation in a 3'UTR- and miRNA-dependent manner by controlling mRNA turnover. This regulation is disturbed by the previously reported MSI1 inhibitor luteolin, providing further evidence for a therapeutic target potential of MSI1 in GBM treatment.

14.
Sci Rep ; 10(1): 13399, 2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753612

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

15.
Genome Biol ; 21(1): 195, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32762776

RESUMO

BACKGROUND: RNA-binding proteins (RBPs) function as master regulators of gene expression. Alterations in RBP expression and function are often observed in cancer and influence critical pathways implicated in tumor initiation and growth. Identification and characterization of oncogenic RBPs and their regulatory networks provide new opportunities for targeted therapy. RESULTS: We identify the RNA-binding protein SERBP1 as a novel regulator of glioblastoma (GBM) development. High SERBP1 expression is prevalent in GBMs and correlates with poor patient survival and poor response to chemo- and radiotherapy. SERBP1 knockdown causes delay in tumor growth and impacts cancer-relevant phenotypes in GBM and glioma stem cell lines. RNAcompete identifies a GC-rich region as SERBP1-binding motif; subsequent genomic and functional analyses establish SERBP1 regulation role in metabolic routes preferentially used by cancer cells. An important consequence of these functions is SERBP1 impact on methionine production. SERBP1 knockdown decreases methionine levels causing a subsequent reduction in histone methylation as shown for H3K27me3 and upregulation of genes associated with neurogenesis, neuronal differentiation, and function. Further analysis demonstrates that several of these genes are downregulated in GBM, potentially through epigenetic silencing as indicated by the presence of H3K27me3 sites. CONCLUSIONS: SERBP1 is the first example of an RNA-binding protein functioning as a central regulator of cancer metabolism and indirect modulator of epigenetic regulation in GBM. By bridging these two processes, SERBP1 enhances glioma stem cell phenotypes and contributes to GBM poorly differentiated state.


Assuntos
Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Neoplasias Encefálicas/etiologia , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/terapia , Epigênese Genética , Feminino , Glioblastoma/etiologia , Glioblastoma/mortalidade , Glioblastoma/terapia , Humanos , Masculino , Camundongos , Neurogênese , Fenótipo , Prognóstico , Estados Unidos/epidemiologia
16.
Sci Rep ; 10(1): 8979, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488114

RESUMO

High-dose radiation is the main component of glioblastoma therapy. Unfortunately, radio-resistance is a common problem and a major contributor to tumor relapse. Understanding the molecular mechanisms driving response to radiation is critical for identifying regulatory routes that could be targeted to improve treatment response. We conducted an integrated analysis in the U251 and U343 glioblastoma cell lines to map early alterations in the expression of genes at three levels: transcription, splicing, and translation in response to ionizing radiation. Changes at the transcriptional level were the most prevalent response. Downregulated genes are strongly associated with cell cycle and DNA replication and linked to a coordinated module of expression. Alterations in this group are likely driven by decreased expression of the transcription factor FOXM1 and members of the E2F family. Genes involved in RNA regulatory mechanisms were affected at the mRNA, splicing, and translation levels, highlighting their importance in radiation-response. We identified a number of oncogenic factors, with an increased expression upon radiation exposure, including BCL6, RRM2B, IDO1, FTH1, APIP, and LRIG2 and lncRNAs NEAT1 and FTX. Several of these targets have been previously implicated in radio-resistance. Therefore, antagonizing their effects post-radiation could increase therapeutic efficacy. Our integrated analysis provides a comprehensive view of early response to radiation in glioblastoma. We identify new biological processes involved in altered expression of various oncogenic factors and suggest new target options to increase radiation sensitivity and prevent relapse.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/radioterapia , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Glioblastoma/genética , Glioblastoma/radioterapia , Splicing de RNA/genética , Transcrição Gênica/genética , Neoplasias Encefálicas/patologia , Ciclo Celular/genética , Linhagem Celular Tumoral , Replicação do DNA/genética , Proteína Forkhead Box M1/genética , Proteína Forkhead Box M1/metabolismo , Expressão Gênica , Glioblastoma/patologia , Humanos , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Biossíntese de Proteínas/genética , Tolerância a Radiação , Radiação Ionizante , Dosagem Radioterapêutica
17.
NPJ Genom Med ; 5: 2, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31969990

RESUMO

Therapy resistance and recurrence in high-grade gliomas are driven by their populations of glioma stem cells (GSCs). Thus, detailed molecular characterization of GSCs is needed to develop more effective therapies. We conducted a study to identify differences in the splicing profile and expression of long non-coding RNAs in proneural and mesenchymal GSC cell lines. Genes related to cell cycle, DNA repair, cilium assembly, and splicing showed the most differences between GSC subgroups. We also identified genes distinctly associated with survival among patients of mesenchymal or proneural subgroups. We determined that multiple long non-coding RNAs with increased expression in mesenchymal GSCs are associated with poor survival of glioblastoma patients. In summary, our study established critical differences between proneural and mesenchymal GSCs in splicing profiles and expression of long non-coding RNA. These splicing isoforms and lncRNA signatures may contribute to the uniqueness of GSC subgroups, thus contributing to cancer phenotypes and explaining differences in therapeutic responses.

18.
Cell Stem Cell ; 26(2): 187-204.e10, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-31956038

RESUMO

Zika virus (ZIKV) causes microcephaly by killing neural precursor cells (NPCs) and other brain cells. ZIKV also displays therapeutic oncolytic activity against glioblastoma (GBM) stem cells (GSCs). Here we demonstrate that ZIKV preferentially infected and killed GSCs and stem-like cells in medulloblastoma and ependymoma in a SOX2-dependent manner. Targeting SOX2 severely attenuated ZIKV infection, in contrast to AXL. As mechanisms of SOX2-mediated ZIKV infection, we identified inverse expression of antiviral interferon response genes (ISGs) and positive correlation with integrin αv (ITGAV). ZIKV infection was disrupted by genetic targeting of ITGAV or its binding partner ITGB5 and by an antibody specific for integrin αvß5. ZIKV selectively eliminated GSCs from species-matched human mature cerebral organoids and GBM surgical specimens, which was reversed by integrin αvß5 inhibition. Collectively, our studies identify integrin αvß5 as a functional cancer stem cell marker essential for GBM maintenance and ZIKV infection, providing potential brain tumor therapy.


Assuntos
Glioblastoma , Células-Tronco Neurais , Infecção por Zika virus , Zika virus , Humanos , Receptores de Vitronectina , Fatores de Transcrição SOXB1/genética
19.
Mol Cancer Res ; 18(1): 68-78, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31624087

RESUMO

13-Cis-retinoic acid (RA) is typically used in postremission maintenance therapy in patients with neuroblastoma. However, side effects and recurrence are often observed. We investigated the use of miRNAs as a strategy to replace RA as promoters of differentiation. miR-124 was identified as the top candidate in a functional screen. Genomic target analysis indicated that repression of a network of transcription factors (TF) could be mediating most of miR-124's effect in driving differentiation. To advance miR-124 mimic use in therapy and better define its mechanism of action, a high-throughput siRNA morphologic screen focusing on its TF targets was conducted and ELF4 was identified as a leading candidate for miR-124 repression. By altering its expression levels, we showed that ELF4 maintains neuroblastoma in an undifferentiated state and promotes proliferation. Moreover, ELF4 transgenic expression was able to counteract the neurogenic effect of miR-124 in neuroblastoma cells. With RNA sequencing, we established the main role of ELF4 to be regulation of cell-cycle progression, specifically through the DREAM complex. Interestingly, several cell-cycle genes activated by ELF4 are repressed by miR-124, suggesting that they might form a TF-miRNA regulatory loop. Finally, we showed that high ELF4 expression is often observed in neuroblastomas and is associated with poor survival. IMPLICATIONS: miR-124 induces neuroblastoma differentiation partially through the downregulation of TF ELF4, which drives neuroblastoma proliferation and its undifferentiated phenotype.


Assuntos
Proteínas de Ligação a DNA/metabolismo , MicroRNAs/metabolismo , Neuroblastoma/metabolismo , Fatores de Transcrição/metabolismo , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Células HEK293 , Células HeLa , Humanos , MicroRNAs/genética , Neuroblastoma/genética , Neuroblastoma/patologia , Taxa de Sobrevida , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Transfecção
20.
Adv Exp Med Biol ; 1157: 29-39, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31342436

RESUMO

Post-transcriptional regulation of gene expression is fundamental for all forms of life, as it critically contributes to the composition and quantity of a cell's proteome. These processes encompass splicing, polyadenylation, mRNA decay, mRNA editing and modification and translation and are modulated by a variety of RNA-binding proteins (RBPs). Alterations affecting RBP expression and activity contribute to the development of different types of cancer. In this chapter, we discuss current research shedding light on the role of different RBPs in gliomas. These studies place RBPs as modulators of critical signaling pathways, establish their relevance as prognostic markers and open doors for new therapeutic strategies.


Assuntos
Glioma , Proteínas de Ligação a RNA , Glioma/fisiopatologia , Humanos , Poliadenilação , Splicing de RNA , Estabilidade de RNA , Proteínas de Ligação a RNA/metabolismo
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