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Early metastatic disease development is one characteristic that defines triple-negative breast cancer (TNBC) as the most aggressive breast cancer (BC) subtype. Numerous studies have identified long non-coding RNAs (lncRNA) as critical players in regulating tumor progression and metastasis formation. Here, we show that MALAT1, a long non-coding RNA known to promote various features of BC malignancy, such as migration and neo angiogenesis, regulates TNBC cell response to hypoxia. By profiling MALAT1-associated transcripts, we discovered that lncRNA MALAT1 interacts with the mRNA encoding WTAP protein, previously reported as a component of the N6-methyladenosine (m6A) modification writer complex. In hypoxic conditions, MALAT1 positively regulates WTAP protein expression, which influences the response to hypoxia by favoring the transcription of the master regulators HIF1α and HIF1ß. Furthermore, WTAP stimulates BC cell migratory ability and the expression of N-Cadherin and Vimentin, hallmarks of epithelial-to-mesenchymal transition (EMT). In conclusion, this study highlights the functional axis comprising MALAT1 and WTAP as a novel prognostic marker of TNBC progression and as a potential target for the development of therapeutic approaches for TNBC treatment.
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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.
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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
Locoregional recurrences represent a frequently unexpected problem in head and neck squamous cell carcinoma (HNSCC). Relapse often (10-30%) occurs in patients with histologically negative resection margins (RMs), probably due to residual tumor cells or hidden pre-cancerous lesions in normal mucosa, both missed by histopathological examination. Therefore, definition of a 'clean' or tumor-negative RM is controversial, demanding for novel approaches to be accurately explored. Here, we evaluated next generation sequencing (NGS) and digital PCR (dPCR) as tools to profile TP53 mutational status and circulating microRNA expression aiming at scoring the locoregional risk of recurrence by means of molecular analyses. Serial monitoring of these biomarkers allowed identifying patients at high risk, laying the ground for accurate tracking of disease evolution and potential intensification of post-operative treatments. Additionally, our pipeline demonstrated its applicability into the clinical routine, being cost-effective and feasible in terms of patient sampling, holding promise to accurately (re)-stage RMs in the era of precision medicine.
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Understanding the mechanisms of breast cancer cell communication underlying cell spreading and metastasis formation is fundamental for developing new therapies. ID4 is a proto-oncogene overexpressed in the basal-like subtype of triple-negative breast cancer (TNBC), where it promotes angiogenesis, cancer stem cells, and BRACA1 misfunction. Here, we show that ID4 expression in BC cells correlates with the activation of motility pathways and promotes the production of VEGFA, which stimulates the interaction of VEGFR2 and integrin ß3 in a paracrine fashion. This interaction induces the downstream focal adhesion pathway favoring migration, invasion, and stress fiber formation. Furthermore, ID4/ VEGFA/ VEGFR2/ integrin ß3 signaling stimulates the nuclear translocation and activation of the Hippo pathway member's YAP and TAZ, two critical executors for cancer initiation and progression. Our study provides new insights into the oncogenic roles of ID4 in tumor cell migration and YAP/TAZ pathway activation, suggesting VEGFA/ VEGFR2/ integrin ß3 axis as a potential target for BC treatment.
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Neoplasias da Mama , Integrina beta3 , Humanos , Feminino , Integrina beta3/metabolismo , Linhagem Celular Tumoral , Transdução de Sinais , Via de Sinalização Hippo , Fator A de Crescimento do Endotélio Vascular , Proteínas Inibidoras de DiferenciaçãoRESUMO
The switch from the normal quiescent vasculature to angiogenesis in tumors is induced by a variety of growth factors, released from cancer and stromal cells upon oxygen and nutrients deprivation. Vascular endothelial growth factor A (VEGF-A) is a potent-secreted mitogen and the only growth factor specific to endothelial cells that is observed almost ubiquitously at sites of angiogenesis. Expression of VEGF-A in cancer cells is controlled through transcriptional and post-transcriptional mechanisms. Post-transcriptional regulation of VEGF-A occurs at multiple levels, through the control of splicing, mRNA stability and translation rate, enabling a fine-tuned expression and release of VEGF-A. Mounting evidence is highlighting the important role played by microRNAs (miRNAs) in the control of VEGF-A mRNA stability and translation in cancer. Moreover, non-coding RNAs, as long non-coding RNAs and circular RNAs, are emerging as crucial modulators of VEGF-A-targeting miRNAs, with consequent ability to modulate VEGF-A expression. This review discusses the recent progress on the ncRNA-related networks controlling VEGF-A expression in cancer cells and provides insights into the complexity of VEGF-A post-transcriptional regulation.
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MicroRNAs , Neoplasias , Humanos , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Células Endoteliais/metabolismo , Regulação da Expressão Gênica , Neoplasias/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/genéticaRESUMO
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.
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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
The TP53 gene is mutated in approximately 60% of all colorectal cancer (CRC) cases. Over 20% of all TP53-mutated CRC tumors carry missense mutations at position R175 or R273. Here we report that CRC tumors harboring R273 mutations are more prone to progress to metastatic disease, with decreased survival, than those with R175 mutations. We identify a distinct transcriptional signature orchestrated by p53R273H, implicating activation of oncogenic signaling pathways and predicting worse outcome. These features are shared also with the hotspot mutants p53R248Q and p53R248W. p53R273H selectively promotes rapid CRC cell spreading, migration, invasion and metastasis. The transcriptional output of p53R273H is associated with preferential binding to regulatory elements of R273 signature genes. Thus, different TP53 missense mutations contribute differently to cancer progression. Elucidation of the differential impact of distinct TP53 mutations on disease features may make TP53 mutational information more actionable, holding potential for better precision-based medicine.
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Neoplasias Colorretais , Proteína Supressora de Tumor p53 , Neoplasias Colorretais/genética , Genes p53 , Humanos , Mutação , Fenótipo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/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.
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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
Non-coding RNAs (ncRNAs) play a pivotal role in regulating the tumor microenvironment (TME) by controlling gene expression at multiple levels. In tumors, ncRNAs can mediate the crosstalk between cancer cells and other cells in the TME, such as immune cells, stromal cells, and endothelial cells, influencing tumor development and progression. Tumor-associated macrophages (TAMs) are among the most abundant inflammatory cells infiltrating solid cancers that promote tumorigenesis, and their infiltration correlates with a poor prognosis in many tumors. Cancer cells produce different ncRNAs that orchestrate TAM recruitment and polarization toward a tumor-promoting phenotype. Tumor-reprogrammed macrophages shape the TME by promoting angiogenesis and tissue remodeling, and suppressing the anti-tumor activity of adaptive immune cells. TAMs can also produce ncRNA molecules that boost cancer cell proliferation and direct their phenotype and metabolic changes facilitating cancer progression and metastasis. This review will focus on the crosstalk between cancer cells and TAMs mediated by microRNAs and long non-coding RNAs during breast cancer (BC) initiation and progression.
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We are delighted to share with you our seventh Journal Club and highlight some of the most interesting papers published recently [...].
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Triple-negative breast cancer (TNBC) is a subtype of breast carcinoma characterized by poor prognosis and high rate of metastasis. Current treatment is based on chemo- and/or radiotherapy and surgery. TNBC is devoid of estrogen, progesterone and HER2 receptors. Although precision medicine has come a long way to ameliorate breast cancer disease management, targeted therapies for the treatment of TNBC patients are still limited. Mounting evidence has shown that non-coding RNAs (ncRNAs) drive many oncogenic processes at the basis of increased proliferation, invasion and angiogenesis in TNBC, strongly contributing to tumor progression and resistance to treatments. Many of these ncRNAs are secreted in the tumor microenvironment (TME) and impinge on the activity of the diverse immune and stromal cell types infiltrating the TME. Importantly, secreted ncRNAs may be detected as circulating molecules in serum/plasma from cancer patients and are emerging a promising diagnostic/therapeutic tools in TNBC. This review aims to discuss novel insights about the role of secreted circulating ncRNAs in the intercellular communication in the tumor microenvironment and their potential clinical use as diagnostic and prognostic non-invasive biomarkers in TNBC.
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BACKGROUND: Squamous cell carcinoma (SCC) of the skin is a common form of nonmelanoma skin cancer. Monocyte chemotactic protein 1-induced protein 1 (MCPIP1), also called Regnase-1, is an RNase with anti-inflammatory properties. In normal human skin, its expression is predominantly restricted to the suprabasal epidermis. The main aim of this study was to investigate whether MCPIP1 is involved in the pathogenesis of SCC. METHODS: We analyzed the distribution of MCPIP1 in skin biopsies of patients with actinic keratoses (AKs) and SCCs. To explore the mechanisms by which MCPIP1 may modulate tumorigenesis in vivo, we established a mouse model of chemically induced carcinogenesis. RESULTS: Skin expression of MCPIP1 changed during the transformation of precancerous lesions into cutaneous SCC. MCPIP1 immunoreactivity was high in the thickened area of the AK epidermis but was predominantly restricted to keratin pearls in fully developed SCC lesions. Accelerated development of chemically induced skin tumors was observed in mice with loss of epidermal MCPIP1 (Mcpip1eKO). Papillomas that developed in Mcpip1eKO mouse skin were larger and characterized by elevated expression of markers typical of keratinocyte proliferation and tumor angiogenesis. This phenotype was correlated with enhanced expression of IL-6, IL-33 and transforming growth factor-beta (TGF-ß). Moreover, our results demonstrated that in keratinocytes, the RNase MCPIP1 is essential for the negative regulation of genes encoding SCC antigens and matrix metallopeptidase 9. CONCLUSIONS: Overall, our results provide a mechanistic understanding of how MCPIP1 contributes to the development of epidermoid carcinoma.
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Carcinoma de Células Escamosas/genética , Epiderme/metabolismo , Ribonucleases/metabolismo , Animais , Humanos , CamundongosRESUMO
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.
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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
Next generation RNA sequencing techniques, implemented in the recent years, have allowed us to identify circular RNAs (circRNAs), covalently closed loop structures resulting in RNA molecules that are more stable than linear RNAs. This class of non-coding RNA is emerging to be involved in a variety of cell functions during development, differentiation, and in many diseases, including cancer. Among the described biological activities, circRNAs have been implicated in microRNA (miRNA) sequestration, modulation of protein-protein interactions and regulation of mRNA transcription. In human cancer, circRNAs were implicated in the control of oncogenic activities such as tumor cell proliferation, epithelial-mesenchymal transition, invasion, metastasis and chemoresistance. The most widely described mechanism of action of circRNAs is their ability to act as competing endogenous RNAs (ceRNAs) for miRNAs, lncRNAs and mRNAs, thus impacting along their axis, despite the fact that a variety of additional mechanisms of action are emerging, representing an open and expanding field of study. Furthermore, research is currently focusing on understanding the possible implications of circRNAs in diagnostics, prognosis prediction, effectiveness of therapies and, eventually, therapeutic intervention in human cancer. The purpose of this review is to discuss new knowledge on the mechanisms of circRNA action, beyond ceRNA, their impact on human cancer and to dissect their potential value as biomarkers and therapeutic targets.
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Many epigenetic modifications occur in glioma, in particular the histone-deacetylase class proteins play a pivotal role in glioma development, driving the proliferation rate and the invasiveness of tumor cells, and modulating the tumor microenvironment. In this study, we evaluated the role of the histone deacetylase HDAC8 in the regulation of the immune response in glioma and tumor growth. We found that inhibition of HDAC8 by the specific inhibitor PCI-34051 reduces tumor volume in glioma mouse models. We reported that HDAC8 modulates the viability and the migration of human and murine glioma cells. Interestingly, HDAC8 inhibition increases the acetylation of alpha-tubulin, suggesting this epigenetic modification controls glioma migration. Furthermore, we identify HDAC8 as a key molecule that supports a poorly immunogenic tumor microenvironment, modulating microglial phenotype and regulating the gene transcription of NKG2D ligands that trigger the Natural Killer cell-mediated cytotoxicity of tumor cells. Altogether, these results identify HDAC8 as a key actor in glioma growth and tumor microenvironment, and pave the way to a better knowledge of the molecular mechanisms of immune escape in glioma.
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Glioma , Histona Desacetilases , Intervenção Coronária Percutânea , Animais , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Histona Desacetilases/imunologia , Histona Desacetilases/metabolismo , Histonas/metabolismo , Imunidade , Camundongos , Microambiente TumoralRESUMO
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.
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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
The miR-15/107 group of microRNAs (miRNAs) encloses 10 annotated human members and is defined based on the presence of the sequence AGCAGC near the mature miRNAs' 5' end. Members of the miR-15/107 group expressed in humans are highly evolutionarily conserved, and seven of these miRNAs are widespread in vertebrate species. Contrary to the majority of miRNAs, which recognize complementary sequences on the 3'UTR region, some members of the miR-15/107 group are peculiarly characterized by the ability to target the coding sequence (CDS) of their target mRNAs, inhibiting translation without strongly affecting their mRNA levels. There is compelling evidence that different members of the miR-15/107 group regulate overlapping lists of mRNA targets but also show target specificity. The ubiquitously expressed miR-15/107 gene group controls several human cellular pathways, such as proliferation, angiogenesis, and lipid metabolism, and might be altered in various diseases, such as neurodegenerative diseases and cancer. Intriguingly, despite sharing the same seed sequence, different members of this family of miRNAs may behave as oncomiRs or as tumor suppressor miRNAs in the context of cancer cells. This review discusses the regulation and functional contribution of the miR-15/107 group to the control of gene expression. Moreover, we particularly focus on the contribution of specific miR-15/107 group members as tumor suppressors in breast cancer, reviewing literature reporting their ability to function as major controllers of a variety of cell pathways and to act as powerful biomarkers in this disease.
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In the recent years thousands of non-coding RNAs have been identified, also thanks to highthroughput sequencing technologies. Among them, circular RNAs (circRNAs) are a well-represented class characterized by the high sequence conservation and cell type specific expression in eukaryotes. They are covalently closed loops formed through back-splicing. Recently, circRNAs were shown to regulate a variety of cellular processes functioning as miRNA sponges, RBP binding molecules, transcriptional regulators, scaffold for protein translation, as well as immune regulators. A growing number of studies are showing that deregulated expression of circRNAs plays important and decisive actions during the development of several human diseases, including cancer. The research on their biogenesis and on the various molecular mechanisms in which they are involved is going very fast, however, there are still few studies that address their involvement in embryogenesis and eukaryotic development. This review has the intent to describe the most recent progress in the study of the biogenesis and molecular activities of circRNAs providing insightful information in the field of embryogenesis and cell differentiation. In addition, we describe the latest research on circRNAs as novel promising biomarkers in diverse types of tumors.