RESUMO
Post-transcriptional mechanisms are fundamental safeguards of progenitor cell identity and are often dysregulated in cancer. Here, we identified regulators of P-bodies as crucial vulnerabilities in acute myeloid leukaemia (AML) through genome-wide CRISPR screens in normal and malignant haematopoietic progenitors. We found that leukaemia cells harbour aberrantly elevated numbers of P-bodies and show that P-body assembly is crucial for initiation and maintenance of AML. Notably, P-body loss had little effect upon homoeostatic haematopoiesis but impacted regenerative haematopoiesis. Molecular characterization of P-bodies purified from human AML cells unveiled their critical role in sequestering messenger RNAs encoding potent tumour suppressors from the translational machinery. P-body dissolution promoted translation of these mRNAs, which in turn rewired gene expression and chromatin architecture in leukaemia cells. Collectively, our findings highlight the contrasting and unique roles of RNA sequestration in P-bodies during tissue homoeostasis and oncogenesis. These insights open potential avenues for understanding myeloid leukaemia and future therapeutic interventions.
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N6-methyladenosine (m6A), the most prevalent internal mRNA modification, plays a critical role in physiological processes by regulating gene expression through modulation of mRNA metabolism at multiple stages. In recent years, m6A has garnered significant attention for a deeper understanding of the initiation, progression, and drug resistance of various cancers, including hematological malignancies. Dysregulation of m6A has been implicated in both cancer promotion and suppression. m6A methylation is a complex regulatory process involving methyltransferases (writers), demethylases (erasers), and proteins that recognize specific m6A modifications (readers). This intricate interplay presents challenges for precisely modulating m6A levels, either globally or at specific sites. This review specifically focuses on the role of m6A in chronic myeloid leukemia (CML), a blood cancer characterized by the BCR-ABL1 fusion. We emphasize its impact on leukemia cell survival and drug resistance mechanisms. Notably, inhibitors targeting m6A regulators show promise in preclinical models, suggesting a potential therapeutic avenue for CML. Integrating our understanding of m6A biology with current treatment strategies may lead to more effective therapies, especially for patients with advanced-stage or resistant CML.
Assuntos
Adenosina , Leucemia Mielogênica Crônica BCR-ABL Positiva , Humanos , Adenosina/análogos & derivados , Adenosina/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Resistencia a Medicamentos Antineoplásicos/genética , Animais , Metiltransferases/metabolismo , Metiltransferases/antagonistas & inibidores , Metiltransferases/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , MetilaçãoRESUMO
N6-methyladenosine (m6A) is one of the most prevalent and conserved RNA modifications. It controls several biological processes, including the biogenesis and function of circular RNAs (circRNAs), which are a class of covalently closed-single stranded RNAs. Several studies have revealed that proteotoxic stress response induction could be a relevant anticancer therapy in Acute Myeloid Leukemia (AML). Furthermore, a strong molecular interaction between the m6A mRNA modification factors and the suppression of the proteotoxic stress response has emerged. Since the proteasome inhibition leading to the imbalance in protein homeostasis is strictly linked to the stress response induction, we investigated the role of Bortezomib (Btz) on m6A regulation and in particular its impact on the modulation of m6A-modified circRNAs expression. Here, we show that treating AML cells with Btz downregulated the expression of the m6A regulator WTAP at translational level, mainly because of increased oxidative stress. Indeed, Btz treatment promoted oxidative stress, with ROS generation and HMOX-1 activation and administration of the reducing agent N-acetylcysteine restored WTAP expression. Additionally, we identified m6A-modified circRNAs modulated by Btz treatment, including circHIPK3, which is implicated in protein folding and oxidative stress regulation. These results highlight the intricate molecular networks involved in oxidative and ER stress induction in AML cells following proteotoxic stress response, laying the groundwork for future therapeutic strategies targeting these pathways.
Assuntos
Adenosina , Leucemia Mieloide Aguda , Estresse Oxidativo , RNA Circular , Humanos , RNA Circular/genética , RNA Circular/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Bortezomib/farmacologia , Linhagem Celular Tumoral , Espécies Reativas de Oxigênio/metabolismo , Fatores de Processamento de RNA/metabolismo , Fatores de Processamento de RNA/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Heme Oxigenase-1/metabolismo , Heme Oxigenase-1/genética , Proteínas Serina-Treonina Quinases , Peptídeos e Proteínas de Sinalização IntracelularRESUMO
In recent years, there has been a growing interest in the role of RNA in diseases and cancers [...].
Assuntos
Neoplasias , RNA , Humanos , RNA/genética , Neoplasias/genéticaRESUMO
A key mechanism driving colorectal cancer (CRC) development is the upregulation of MYC and its targets, including ornithine decarboxylase (ODC), a master regulator of polyamine metabolism. Elevated polyamines promote tumorigenesis in part by activating DHPS-mediated hypusination of the translation factor eIF5A, thereby inducing MYC biosynthesis. Thus, MYC, ODC and eIF5A orchestrate a positive feedback loop that represents an attractive therapeutic target for CRC therapy. Here we show that combined inhibition of ODC and eIF5A induces a synergistic antitumor response in CRC cells, leading to MYC suppression. We found that genes of the polyamine biosynthesis and hypusination pathways are significantly upregulated in colorectal cancer patients and that inhibition of ODC or DHPS alone limits CRC cell proliferation through a cytostatic mechanism, while combined ODC and DHPS/eIF5A blockade induces a synergistic inhibition, accompanied to apoptotic cell death in vitro and in mouse models of CRC and FAP. Mechanistically, we found that this dual treatment causes complete inhibition of MYC biosynthesis in a bimodal fashion, by preventing translational elongation and initiation. Together, these data illustrate a novel strategy for CRC treatment, based on the combined suppression of ODC and eIF5A, which holds promise for the treatment of CRC.
Assuntos
Neoplasias Colorretais , Fatores de Iniciação de Peptídeos , Poliaminas , Proteínas Proto-Oncogênicas c-myc , Animais , Camundongos , Apoptose , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Ornitina Descarboxilase/genética , Ornitina Descarboxilase/metabolismo , Ornitina Descarboxilase/farmacologia , Poliaminas/metabolismo , Humanos , Fatores de Iniciação de Peptídeos/genética , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fator de Iniciação de Tradução Eucariótico 5ARESUMO
The field of RNA modification, also referred to as "epitranscriptomics," is gaining more and more interest from the scientific community. More than 160 chemical modifications have been identified in RNA molecules, but the functional significance of most of them still needs to be clarified. In this review, we discuss the role of N6,2'-O-dimethyladenosine (m6Am) in gene expression regulation. m6Am is present in the first transcribed nucleotide close to the cap in many mRNAs and snRNAs in mammals and as internal modification in the snRNA U2. The writer and eraser proteins for these modifications have been recently identified and their deletions have been utilized to understand their contributions in gene expression regulation. While the role of U2 snRNA-m6Am in splicing regulation has been reported by different independent studies, conflicting data were found for the role of cap-associated m6Am in mRNA stability and translation. However, despite the open debate on the role of m6Am in mRNA expression, the modulation of regulators produced promising results in cancer cells. We believe that the investigation on m6Am will continue to yield relevant results in the future.
Assuntos
Adenosina , Regulação da Expressão Gênica , Animais , Metilação , Adenosina/genética , Adenosina/metabolismo , RNA Mensageiro/metabolismo , Splicing de RNA , RNA Nuclear Pequeno/metabolismo , RNA/metabolismo , Mamíferos/metabolismoRESUMO
Small cell lung cancer (SCLC) is treated as a homogeneous disease, although the expression of NEUROD1, ASCL1, POU2F3, and YAP1 identifies distinct molecular subtypes. The MYC oncogene, amplified in SCLC, was recently shown to act as a lineage-specific factor to associate subtypes with histological classes. Indeed, MYC-driven SCLCs show a distinct metabolic profile and drug sensitivity. To disentangle their molecular features, we focused on the co-amplified PVT1, frequently overexpressed and originating circular (circRNA) and chimeric RNAs. We analyzed hsa_circ_0001821 (circPVT1) and PVT1/AKT3 (chimPVT1) as examples of such transcripts, respectively, to unveil their tumorigenic contribution to SCLC. In detail, circPVT1 activated a pro-proliferative and anti-apoptotic program when over-expressed in lung cells, and knockdown of chimPVT1 induced a decrease in cell growth and an increase of apoptosis in SCLC in vitro. Moreover, the investigated PVT1 transcripts underlined a functional connection between MYC and YAP1/POU2F3, suggesting that they contribute to the transcriptional landscape associated with MYC amplification. In conclusion, we have uncovered a functional role of circular and chimeric PVT1 transcripts in SCLC; these entities may prove useful as novel biomarkers in MYC-amplified tumors.
Assuntos
Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Humanos , Carcinoma de Pequenas Células do Pulmão/genética , Neoplasias Pulmonares/genética , Proliferação de Células/genética , Apoptose/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Proteínas Proto-Oncogênicas c-akt/genéticaRESUMO
Despite its discovery in the early 1970s, m6A modification within mRNA molecules has only powerfully entered the oncology field in recent years. This chemical modification can control all aspects of the maturation of mRNAs, both in the nucleus and in the cytoplasm. Thus, the alteration in expression levels of writers, erasers, and readers may significantly contribute to the alteration of gene expression observed in cancer. In particular, the activation of oncogenic pathways can lead to an alteration of the global rate of mRNA translation or the selective translation of specific mRNAs. In both cases, m6A can play an important role. In this review, we highlight the role of m6A in the regulation of translation by focusing on regulatory mechanisms and cancer-related functions of this novel but still controversial field.
Assuntos
Adenosina , Neoplasias , Adenosina/metabolismo , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/terapia , Proteômica , RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Vascular Endothelial Growth Factor A (VEGFA) is the most commonly expressed angiogenic growth factor in solid tumors and is generated as multiple isoforms through alternative mRNA splicing. Here, we show that lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) and ID4 (inhibitor of DNA-binding 4) protein, previously referred to as regulators of linear isoforms of VEGFA, induce back-splicing of VEGFA exon 7, producing circular RNA circ_0076611. Circ_0076611 is detectable in triple-negative breast cancer (TNBC) cells and tissues, in exosomes released from TNBC cells and in the serum of breast cancer patients. Circ_0076611 interacts with a variety of proliferation-related transcripts, included MYC and VEGFA mRNAs, and increases cell proliferation and migration of TNBC cells. Mechanistically, circ_0076611 favors the expression of its target mRNAs by facilitating their interaction with components of the translation initiation machinery. These results add further complexity to the multiple VEGFA isoforms expressed in cancer cells and highlight the relevance of post-transcriptional regulation of VEGFA expression in TNBC cells.
Assuntos
MicroRNAs , RNA Longo não Codificante , Neoplasias de Mama Triplo Negativas , Humanos , MicroRNAs/genética , Isoformas de Proteínas/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Thymic Epithelial Tumors (TETs) arise from epithelial cells of the thymus and are very rare neoplasms comprising Thymoma, Thymic carcinoma, and Thymic Neuroendocrine tumors that still require in-depth molecular characterization. Long non-coding RNAs (lncRNAs) are emerging as relevant gene expression modulators involved in the deregulation of several networks in almost all types of human cancer, including TETs. LncRNAs act at different control levels in the regulation of gene expression, from transcription to translation, and modulate several pathways relevant to cell fate determination under normal and pathological conditions. The activity of lncRNAs is strongly dependent on their expression, localization, and post-transcriptional modifications. Starting from our recently published studies, this review focuses on the involvement of lncRNAs in the acquisition of malignant traits by neoplastic thymic epithelial cells, and describes the possible use of these molecules as targets for the design of novel therapeutic approaches specific for TET. Furthermore, the involvement of lncRNAs in myasthenia gravis (MG)-related thymoma, which is still under investigation, is discussed.
Assuntos
Neoplasias Epiteliais e Glandulares , RNA Longo não Codificante , Timoma , Neoplasias do Timo , Células Epiteliais/metabolismo , Humanos , Neoplasias Epiteliais e Glandulares/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Timoma/genética , Timoma/patologia , Neoplasias do Timo/genética , Neoplasias do Timo/patologiaRESUMO
BACKGROUND: Thymic epithelial tumors (TETs) are rare neoplasms, originating from epithelial thymic cells. The oncogenic potential of these rare neoplasms is still largely undefined, and a deeper molecular characterization could result in a relevant advance in their management, greatly improving diagnosis, prognosis and treatment choice. Deregulation of N6-methyladenosine (m6A) RNA modification, catalyzed by the METTL3/METTL14 methyltransferase complex, is emerging as a relevant event in cell differentiation and carcinogenesis. Various studies have reported that altered expression of METTL3 is associated with an aggressive malignant phenotype and favors migration and invasiveness, but its role in Thymic Tumors remains unknown. RESULTS: In this study, we characterized that METTL3 contributes to Thymic Epithelial Tumor phenotype. We evidenced that METTL3 is overexpressed in tumor tissue compared to normal counterpart. Silencing of METTL3 expression in thymic carcinoma cells results in reduced cell proliferation and overall translation rate. Of note, METTL3 is responsible for the induction of c-MYC expression in TET cells. Specifically, high expression of c-MYC protein is enabled by lncRNA MALAT1, which is methylated and delocalized by METTL3. Interestingly, blocking of c-MYC by using JQ1 inhibitor cooperates with METTL3 depletion in the inhibition of proliferation and induction of cell death. CONCLUSION: This study highlighted METTL3 as a tumor promoter in Thymic tumors and c-MYC as a promising target to be exploited for the treatment of TET.
Assuntos
Metilação de DNA/genética , Regulação Neoplásica da Expressão Gênica/genética , Metiltransferases/genética , Neoplasias Epiteliais e Glandulares/genética , Proteínas Proto-Oncogênicas c-myc/genética , Neoplasias do Timo/genética , Fatores de Transcrição/genética , Células Cultivadas , HumanosRESUMO
Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm caused by the presence of tyrosine kinase BCR-ABL1 fusion protein, which deregulate transcription and mRNA translation. Tyrosine kinase inhibitors (TKIs) are the first-choice treatment. However, resistance to TKIs remains a challenge to cure CML patients. Here, we reveal that the m6A methyltransferase complex METTL3/METTL14 is upregulated in CML patients and that is required for proliferation of primary CML cells and CML cell lines sensitive and resistant to the TKI imatinib. We demonstrate that depletion of METTL3 strongly impairs global translation efficiency. In particular, our data show that METTL3 is crucial for the expression of genes involved in ribosome biogenesis and translation. Specifically, we found that METTL3 directly regulates the level of PES1 protein identified as an oncogene in several tumors. We propose a model in which nuclear METTL3/METTL14 methyltransferase complex modified nascent transcripts whose translation is enhanced by cytoplasmic localization of METTL3, independently from its catalytic activity. In conclusion, our results point to METTL3 as a novel relevant oncogene in CML and as a promising therapeutic target for TKI resistant CML.
Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Metiltransferases/metabolismo , Biossíntese de Proteínas , Adenosina/análogos & derivados , Adenosina/metabolismo , Catálise , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células , Sobrevivência Celular , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Mesilato de Imatinib/farmacologia , Mesilato de Imatinib/uso terapêutico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Modelos Biológicos , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Regulação para CimaRESUMO
Growth and maturation of hematopoietic stem cells (HSCs) are largely controlled at both transcriptional and post-transcriptional levels. In particular, hematopoietic development requires a tight control of protein synthesis. Furthermore, translational deregulation strongly contributes to hematopoietic malignancies. Researchers have recently identified a new layer of gene expression regulation that consists of chemical modification of RNA species, which led to the birth of the epitranscriptomics field. RNA modifications provide an additional level of control in hematopoietic development by acting as post-transcriptional regulators of lineage-specific genetic programs. Other reviews have already described the important role of the N6-methylation of adenosine (m6A) within mRNA species in regulating hematopoietic differentiation and diseases. The aim of this review is to summarize the current status of the role of RNA modifications in the regulation of ribosome function, beyond m6A. In particular, we discuss the importance of RNA modifications in tRNA and rRNA molecules. By balancing translational rate and fidelity, they play an important role in regulating normal and malignant hematopoietic development.
Assuntos
Adenosina/análogos & derivados , Leucemia/genética , Processamento Pós-Transcricional do RNA , RNA/genética , Ribossomos/genética , Adenosina/genética , Animais , Regulação Leucêmica da Expressão Gênica , Humanos , RNA Mensageiro/genética , RNA Ribossômico/genética , RNA de Transferência/genéticaRESUMO
BACKGROUND: N6-methyladenosine (m6A) and adenosine-to-inosine (A-to-I) RNA editing are two of the most abundant RNA modification events affecting adenosines in mammals. Both these RNA modifications determine mRNA fate and play a pivotal role in tumor development and progression. RESULTS: Here, we show that METTL3, upregulated in glioblastoma, methylates ADAR1 mRNA and increases its protein level leading to a pro-tumorigenic mechanism connecting METTL3, YTHDF1, and ADAR1. We show that ADAR1 plays a cancer-promoting role independently of its deaminase activity by binding CDK2 mRNA, underlining the importance of ADARs as essential RNA-binding proteins for cell homeostasis as well as cancer progression. Additionally, we show that ADAR1 knockdown is sufficient to strongly inhibit glioblastoma growth in vivo. CONCLUSIONS: Hence, our findings underscore METTL3/ADAR1 axis as a novel crucial pathway in cancer progression that connects m6A and A-to-I editing post-transcriptional events.
Assuntos
Adenosina Desaminase/genética , Carcinogênese/genética , Glioblastoma/genética , Metiltransferases/genética , Proteínas de Ligação a RNA/genética , Adenosina/metabolismo , Adulto , Animais , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Glioblastoma/patologia , Humanos , Masculino , Mutagênese , Isoformas de Proteínas , RNA Mensageiro/metabolismoRESUMO
Eukaryotic Translation Initiation Factor 5A (EIF5A) is a translation factor regulated by hypusination, a unique posttranslational modification catalyzed by deoxyhypusine synthetase (DHPS) and deoxyhypusine hydroxylase (DOHH) starting from the polyamine spermidine. Emerging data are showing that hypusinated EIF5A regulates key cellular processes such as autophagy, senescence, polyamine homeostasis, energy metabolism, and plays a role in cancer. However, the effects of EIF5A inhibition in preclinical cancer models, the mechanism of action, and specific translational targets are still poorly understood. We show here that hypusinated EIF5A promotes growth of colorectal cancer (CRC) cells by directly regulating MYC biosynthesis at specific pausing motifs. Inhibition of EIF5A hypusination with the DHPS inhibitor GC7 or through lentiviral-mediated knockdown of DHPS or EIF5A reduces the growth of various CRC cells. Multiplex gene expression analysis reveals that inhibition of hypusination impairs the expression of transcripts regulated by MYC, suggesting the involvement of this oncogene in the observed effect. Indeed, we demonstrate that EIF5A regulates MYC elongation without affecting its mRNA content or protein stability, by alleviating ribosome stalling at five distinct pausing motifs in MYC CDS. Of note, we show that blockade of the hypusination axis elicits a remarkable growth inhibitory effect in preclinical models of CRC and significantly reduces the size of polyps in APCMin/+ mice, a model of human familial adenomatous polyposis (FAP). Together, these data illustrate an unprecedented mechanism, whereby the tumor-promoting properties of hypusinated EIF5A are linked to its ability to regulate MYC elongation and provide a rationale for the use of DHPS/EIF5A inhibitors in CRC therapy.
Assuntos
Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Lisina/análogos & derivados , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas de Ligação a RNA/metabolismo , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Neoplasias Colorretais/genética , Regulação para Baixo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Lisina/metabolismo , Camundongos Nus , Fases de Leitura Aberta/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Fatores de Iniciação de Peptídeos/química , Peptídeos/metabolismo , Poliaminas/metabolismo , Biossíntese de Proteínas , Proteínas de Ligação a RNA/química , Fator de Iniciação de Tradução Eucariótico 5ARESUMO
Long non-coding RNAs are emerging as new molecular players involved in many biological processes, such as proliferation, apoptosis, cell cycle, migration, and differentiation. Their aberrant expression has been reported in variety of diseases. The aim of this study is the identification and functional characterization of clinically relevant lncRNAs responsible for the inhibition of miR-145-5p, a key tumor suppressor in thymic epithelial tumors (TETs). Starting from gene expression analysis by microarray in a cohort of fresh frozen thymic tumors and normal tissues, we identified LINC00174 as upregulated in TET. Interestingly, LINC00174 expression is positively correlated with a 5-genes signature in TETs. Survival analyses, performed on the TCGA dataset, showed that LINC00174 and its associated 5-genes signature are prognostic in TETs. Specifically, we show that LINC00174 favors the expression of SYBU, FEM1B, and SCD5 genes by sponging miR-145-5p, a well-known tumor suppressor microRNA downregulated in a variety of tumors, included TETs. Functionally, LINC00174 impacts on cell migration and lipid metabolism. Specifically, SCD5, one of the LINC00174-associated genes, is implicated in the control of lipid metabolism and promotes thymic cancer cells migration. Our study highlights that LINC00174 and its associated gene signature are relevant prognostic indicators in TETs. Of note, we here show that a key controller of lipid metabolism, SCD5, augments the migration ability of TET cells, creating a link between lipids and motility, and highlighting these pathways as relevant targets for the development of novel therapeutic approaches for TET.
Assuntos
Biomarcadores Tumorais/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/metabolismo , Movimento Celular , Regulação Neoplásica da Expressão Gênica , Metabolismo dos Lipídeos , Neoplasias Epiteliais e Glandulares/patologia , RNA Longo não Codificante/genética , Neoplasias do Timo/patologia , Apoptose , Biomarcadores Tumorais/genética , Proteínas de Transporte/genética , Proteínas de Ciclo Celular/genética , Proliferação de Células , Perfilação da Expressão Gênica , Humanos , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Epiteliais e Glandulares/metabolismo , Prognóstico , Taxa de Sobrevida , Neoplasias do Timo/genética , Neoplasias do Timo/metabolismo , Células Tumorais CultivadasRESUMO
N6-methyladenosine (m6A) is an RNA modification well-known for its contribution to different processes controlling RNA metabolism, including splicing, stability, and translation of mRNA. Conversely, the role of m6A on the biogenesis and function of circular RNAs (circRNAs) has yet to be addressed. circRNAs belong to a class of covalently closed transcripts produced via a back-splicing reaction whereby a downstream 5' splice donor site fuses to an upstream 3' splice acceptor site. Starting from circ-ZNF609 as a study case, we discover that specific m6As control its accumulation and that METTL3 and YTHDC1 are required to direct the back-splicing reaction. This feature is shared with other circRNAs because we find a significant direct correlation among METTL3 requirement, YTHDC1 binding, and the ability of m6A exons to undergo back-splicing. Finally, because circ-ZNF609 displays the ability to be translated, we show that m6A modifications, through recognition by YTHDF3 and eIF4G2, modulate its translation.
Assuntos
Adenosina/análogos & derivados , Metiltransferases/metabolismo , RNA Circular/metabolismo , Adenosina/metabolismo , Processamento Alternativo , Pré-Escolar , Feminino , Células HEK293 , Células HeLa , Humanos , Masculino , Proteínas do Tecido Nervoso , Fatores de Processamento de RNARESUMO
Acute myeloid leukemia (AML) is often characterized by the expression of fusion or mutant proteins that cause impaired differentiation and enhanced proliferation and survival. The presence of mutant proteins prone to misfolding can render the cells sensitive to endoplasmic reticulum (ER) stress and oxidative stress that could otherwise be overcome. Here, we show that the triple combination of the differentiating agent retinoic acid (RA), the ER stress-inducing drug tunicamycin (Tm), and arsenic trioxide (ATO), able to generate oxidative stress, leads to the death of AML cell lines expressing fusion proteins involving the gene MLL and the internal tandem duplication (ITD) in the FLT3 tyrosine kinase receptor. Importantly, the combination of RA, Tm, and ATO decreased the colony-forming capacity of primary leukemic blasts bearing the FLT-ITD mutation without affecting healthy hematopoietic progenitor cells. We demonstrate in cell lines that combination of these drugs generates ER and oxidative stresses and impairs maturation and causes accumulation of FLT3 protein in the ER. Our data provide a proof of concept that low amounts of drugs that generate ER and oxidative stresses combined with RA could be an effective targeted therapy to hit AML cells characterized by MLL fusion proteins and FLT3-ITD mutation.
Assuntos
Morte Celular , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Estresse Oxidativo , Sequências de Repetição em Tandem , Tretinoína/farmacologia , Resposta a Proteínas não Dobradas , Tirosina Quinase 3 Semelhante a fms/genética , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Duplicação Gênica , Humanos , Leucemia Mieloide Aguda/patologia , Estresse Oxidativo/efeitos dos fármacos , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
RNA chemical modifications in coding and non-coding RNAs have been known for decades. They are generally installed by specific enzymes and, in some cases, can be read and erased by other specific proteins. The impact of RNA chemical modifications on gene expression regulation and the reversible nature of some of these modifications led to the birth of the word epitranscriptomics, in analogy with the changes that occur on DNA and histones. Among more than 100 different modifications identified so far, most of the epitranscriptomics studies focused on the N 6-methyladenosine (m6A), which is the more abundant internal modification in protein coding RNAs. m6A can control several pathways of gene expression, including spicing, export, stability, and translation. In this review, we describe the interplay between m6A and non-coding RNAs, in particular microRNAs and lncRNAs, with examples of its role in gene expression regulation. Finally, we discuss its relevance in cell development and disease.