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The SWI/SNF complex, also known as the BRG1/BRM-associated factor (BAF) complex, represents a critical regulator of chromatin remodeling mechanisms in mammals. It is alternatively referred to as mSWI/SNF and has been suggested to be imbalanced in human disease compared with human health. Three types of BAF assemblies associated with it have been described, including (1) canonical BAF (cBAF), (2) polybromo-associated BAF (PBAF), and (3) non-canonical BAF (ncBAF) complexes. Each of these BAF assemblies plays a role, either functional or dysfunctional, in governing gene expression patterns, cellular processes, epigenetic mechanisms, and biological processes. Recent evidence increasingly links the dysregulation of mSWI/SNF complexes to various human non-malignant lung chronic disorders and lung malignant diseases. This review aims to provide a comprehensive general state-of-the-art and a profound examination of the current understanding of mSWI/SNF assembly processes, as well as the structural and functional organization of mSWI/SNF complexes and their subunits. In addition, it explores their intricate functional connections with potentially dysregulated transcription factors, placing particular emphasis on molecular and cellular pathogenic processes in lung diseases. These processes are reflected in human epigenome aberrations that impact clinical and therapeutic levels, suggesting novel perspectives on the diagnosis and molecular therapies for human respiratory diseases.
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Ensamble y Desensamble de Cromatina , Proteínas Cromosómicas no Histona , Epigénesis Genética , Enfermedades Pulmonares , Factores de Transcripción , Humanos , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Animales , Enfermedades Pulmonares/genética , Enfermedades Pulmonares/terapia , Enfermedades Pulmonares/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/genética , ADN Helicasas/genética , ADN Helicasas/metabolismo , Regulación de la Expresión Génica , Proteínas NuclearesRESUMEN
Signal transducer and activator of transcription 6 (STAT6) promotes tumorigenesis by decreasing the Forkhead box P3+ (Foxp3+) cell frequency allowing for the infiltration of inflammatory cells during the early stages of colitis-associated cancer (CAC). In this study, we dissected the role of STAT6 in the generation of inducible in vitro regulatory T cells (iTregs) and peripheral in vivo Tregs (pTregs) under inflammatory conditions. In in vitro assays, when STAT6 was lacking, iTregs preserved a stable phenotype and expressed high levels of Foxp3 and CD25 during long expansion periods, even in the presence of IL-6. This effect was associated with increased in vitro suppressive ability, over-expression of programmed death-1 (PD-1), CTLA-4, and Foxp3, and decreased IFN-γ expression. Furthermore, iTregs developed during STAT6 deficiency showed a higher demethylation status for the FOXP3 Treg-specific demethylated region (TSDR), coupled with lower DNA methyltransferase 1 (DNMT1) mRNA expression, suggesting that STAT6 may lead to Foxp3 silencing. Using a mouse model of CAC, the STAT6-/- pTregs expressed a more activated phenotype at the intestine, had higher suppressive capacity, and expressed more significant levels of PD-1 and latency-associated peptide of TGF-ß (LAP) associated with their ability to attenuate tumor development. These data suggest that STAT6 signaling impairs the induction, stability, and suppressive capacity of Tregs developed in vitro or in vivo during gut inflammation.
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Receptor de Muerte Celular Programada 1 , Linfocitos T Reguladores , Linfocitos T Reguladores/metabolismo , Factor de Transcripción STAT6/genética , Factor de Transcripción STAT6/metabolismo , Receptor de Muerte Celular Programada 1/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Factores de Transcripción Forkhead/metabolismoRESUMEN
In 2013, recognizing that Colorectal Cancer (CRC) is the second leading cause of death by cancer worldwide and that it was a neglected disease increasing rapidly in Mexico, the community of researchers at the Biomedicine Research Unit of the Facultad de Estudios Superiores Iztacala from the Universidad Nacional Autónoma de México (UNAM) established an intramural consortium that involves a multidisciplinary group of researchers, technicians, and postgraduate students to contribute to the understanding of this pathology in Mexico. This article is about the work developed by the Mexican Colorectal Cancer Research Consortium (MEX-CCRC): how the Consortium was created, its members, and its short- and long-term goals. Moreover, it is a narrative of the accomplishments of this project. Finally, we reflect on possible strategies against CRC in Mexico and contrast all the data presented with another international strategy to prevent and treat CRC. We believe that the Consortium's characteristics must be maintained to initiate a national strategy, and the reported data could be useful to establish future collaborations with other countries in Latin America and the world.
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Neoplasias Colorrectales , Estudiantes , Humanos , México , Estudios Interdisciplinarios , Terapias en Investigación , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/terapiaRESUMEN
OBJECTIVES: This study aimed to evaluate whether the expression of circulating dystromiRs and a group of oxidative stress-related (OS-R) miRNAs is associated with muscle injury and circulating metabolic parameters in Duchenne muscular dystrophy (DMD) patients. METHODS: Twenty-four DMD patients were included in this cross-sectional study. Clinical scales to evaluate muscle injury (Vignos, GMFCS, Brooke, and Medical Research Council), enzymatic muscle injury parameters (CPK, ALT, and AST), anthropometry, metabolic indicators, physical activity, serum dystromiRs (miR-1-3p, miR-133a-3p, and miR-206), and OS-R miRNAs (miR-21-5p, miR-31-5p, miR-128-3p, and miR-144-3p) levels were measured in ambulatory and non-ambulatory DMD patients. RESULTS: DystromiRs (except miR-1-3p) and miRNAs OS-R levels were lower (p-value <.05) in the non-ambulatory group than the ambulatory group. The expression of those miRNAs correlated with Vignos scale score (For instance, rho = -0.567, p-value <0.05 for miR-21-5p) and with other scales scores of muscle function and strength. CPK, AST, and ALT concentration correlated with expression of all miRNAs (For instance, rho = 0.741, p-value <.05 between miR-206 level and AST concentration). MiR-21-5p level correlated with glucose concentration (rho = -0.369, p-value = .038), and the miR-1-3p level correlated with insulin concentration (rho = 0.343, p-value = .05). CONCLUSIONS: Non-ambulatory DMD patients have lower circulating dystromiRs and OS-R miRNAs levels than ambulatory DMD patients. The progressive muscle injury is associated with a decrease in the expression of those miRNAs, evidencing DMD progress. These findings add new information about the natural history of DMD.
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MicroARN Circulante , Insulinas , MicroARNs , Distrofia Muscular de Duchenne , Biomarcadores , Estudios Transversales , Glucosa , Humanos , Músculos/metabolismo , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/metabolismoRESUMEN
The differentiation between influenza and coronavirus disease 2019 (COVID-19) could constitute a diagnostic challenge during the ongoing winter owing to their clinical similitude. Thus, novel biomarkers are required to enable making this distinction. Here, we evaluated whether the surfactant protein D (SP-D), a collectin produced at the alveolar epithelium with known immune properties, was useful to differentiate pandemic influenza A(H1N1) from COVID-19 in critically ill patients. Our results revealed high serum SP-D levels in patients with severe pandemic influenza but not those with COVID-19. This finding was validated in a separate cohort of mechanically ventilated patients with COVID-19 who also showed low plasma SP-D levels. However, plasma SP-D levels did not distinguish seasonal influenza from COVID-19 in mild-to-moderate disease. Finally, we found that high serum SP-D levels were associated with death and renal failure among severe pandemic influenza cases. Thus, our studies have identified SP-D as a unique biomarker expressed during severe pandemic influenza but not COVID-19.
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COVID-19/genética , Expresión Génica , Interacciones Huésped-Patógeno/genética , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/genética , Proteína D Asociada a Surfactante Pulmonar/genética , SARS-CoV-2 , Adulto , Anciano , Biomarcadores , COVID-19/sangre , COVID-19/diagnóstico , COVID-19/virología , Coinfección , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Gripe Humana/diagnóstico , Gripe Humana/virología , Masculino , Persona de Mediana Edad , Pronóstico , Proteína D Asociada a Surfactante Pulmonar/sangre , Índice de Severidad de la Enfermedad , Evaluación de Síntomas , Adulto JovenRESUMEN
[This corrects the article DOI: 10.1155/2019/2056085.].
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Colitis-associated colorectal cancer (CRC) development has been shown to be related to chronically enhanced inflammation. Macrophage migration inhibitory factor (MIF) is an inflammatory mediator that favors inflammatory cytokine production and has chemotactic properties for the recruitment of macrophages (Møs) and T cells. Here, we investigated the role of MIF in the inflammatory response and recruitment of immune cells in a murine model of chemical carcinogenesis to establish the impact of MIF on CRC genesis and malignancy. We used BALB/c MIF-knockout (MIF-/-) and wild-type (WT) mice to develop CRC by administering intraperitoneal (i.p.) azoxymethane and dextran sodium sulfate in drinking water. Greater tumor burdens were observed in MIF-/- mice than in WT mice. Tumors from MIF-/- mice were histologically identified to be more aggressive than tumors from WT mice. The localization of MIF suggests that it is also involved in cell differentiation. The relative gene expression of il-17, measured by real-time PCR, was higher in MIF-/- CRC mice, compared to the WT CRC and healthy MIF-/- mice. Importantly, compared to the WT intestinal epithelium, lower percentages of tumor-associated Møs were found in the MIF-/- intestinal epithelium. These results suggest that MIF plays a role in controlling the initial development of CRC by attracting Møs to the tumor, which is a condition that favors the initial antitumor responses.
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Colitis/metabolismo , Colitis/patología , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Factores Inhibidores de la Migración de Macrófagos/metabolismo , Macrófagos/metabolismo , Linfocitos T/metabolismo , Animales , Progresión de la Enfermedad , Femenino , Citometría de Flujo , Inmunohistoquímica , Factores Inhibidores de la Migración de Macrófagos/genética , Ratones , Ratones Endogámicos BALB C , Ratones NoqueadosRESUMEN
OBJECTIVE: To perform a systematic review of the main epigenetic aberrations involved in non-small cell lung carcinomas' (NSCLC) diagnosis, progression, and therapeutics. MATERIALS AND METHODS: We performed a systematic review of the scientific literature on lung cancer epigenetics, focusing on NSCLC. RESULTS: Several advances in the molecular study of classical epigenetic mechanisms and massive studies of lung cancer epigenome have contributed relevant new evidence revealing that various molecular complexes are functionally influencing genetic-epigenetic and transcriptional mechanisms that promote lung tumorigenesis (initiation, promotion, and progression), and are also involved in NSCLC therapyresistance mechanisms. CONCLUSIONS: Several epigenetic complexes and mechanisms must be analyzed and considered for the design of new and efficient therapies, which could be fundamental to develop an integrated knowledge to achieve a comprehensive lung cancer personalized medicine.
OBJETIVO: Realizar una revisión sistemática y estructurada de las principales aberraciones epigenéticas involucradas en el diagnóstico, progresión y terapia del cáncer pulmonar de células no pequeñas (CPCNP). MATERIAL Y MÉTODOS: Revisión sistemática de literatura científica sobre epigenética del cáncer pulmonar del grupo CPCNP. RESULTADOS: El estudio de los diversos mecanismos epigenéticos y su impronta epigenética en el epigenoma del cáncer pulmonar han arrojado nuevas evidencias a nivel biológico, biomédico y médico-clínico del impacto que los mecanismos epigenéticotranscripcionales promueven de manera activa y reversible sobre los procesos de tumorigénesis, progresión histopatológica y mecanismos de resistencia a la terapia oncológica pulmonar. CONCLUSIONES: Deben analizarse diferentes complejos y mecanismos epigenéticos para el estudio y diseño de esquemas nuevos y eficaces de terapia epigenética, los cuales podrían ser fundamentales para desarrollar un conocimiento integral en el desarrollo de la medicina personalizada en el cáncer pulmonar del grupo CPCNP.
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Carcinoma de Pulmón de Células no Pequeñas/genética , Epigénesis Genética , Neoplasias Pulmonares/genética , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/terapia , Metilación de ADN/genética , Progresión de la Enfermedad , Histonas/genética , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapiaRESUMEN
Malignant pleural mesothelioma (MPM) is a rare but aggressive tumor that originates in the pleura, is diagnosed in advanced stages and has a poor prognosis. Accurate diagnosis of MPM is often difficult and complex, and the gold standard diagnosis test is based on qualitative analysis of markers in pleural tissue by immunohistochemical staining. Therefore, it is necessary to develop quantitative and non-subjective alternative diagnostic tools. MicroRNAs are non-coding RNAs that regulate essential cellular mechanisms at the post-transcriptional level. Recent evidence indicates that miRNA expression in tissue and body fluids is aberrant in various tumors, revealing miRNAs as promising diagnostic biomarkers. This review summarizes evidence regarding secreted and tissue miRNAs as biomarkers of MPM and the biological characteristics associated with their potential diagnostic value. In addition to studies regarding miRNAs with potential diagnostic value for MPM, studies that aimed to identify the miRNAs involved in molecular mechanisms associated with MPM development are described with an emphasis on relevant aspects of the experimental designs that may influence the accuracy, consistency and real diagnostic value of currently reported data.
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Biomarcadores de Tumor/genética , Neoplasias Pulmonares/genética , Mesotelioma/genética , MicroARNs/genética , Neoplasias Pleurales/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/patología , Mesotelioma/diagnóstico , Mesotelioma/patología , Mesotelioma Maligno , Neoplasias Pleurales/diagnóstico , Neoplasias Pleurales/patología , Distribución TisularRESUMEN
BACKGROUND: Overproduction of pro-inflammatory cytokines and chemokines is frequently associated with severe clinical manifestations in patients infected with influenza A/H1N1 virus. Micro-RNAs (miRNAs) are highly conserved small non-coding RNA molecules that post-transcriptionally regulate gene expression and are potential biomarkers and therapeutic targets in different inflammatory conditions. METHODS: We studied the circulating and miRNA profiles in critically ill A/H1N1 patients, A/H1N1 patients with milder disease, asymptomatic housemates and healthy controls. Cytokine, chemokine and growth factors that were potential targets of differentially expressed miRNAs were assessed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and interactome analysis of these miRNAs were also performed. RESULTS: Critically ill patients exhibited a significant over-expression of circulating miR-150 (p<0.005) when compared to patients with milder disease. miR-29c, miR-145 and miR-22 were differentially expressed in patients with severe A/H1N1 disease whereas miR-210, miR-126 and miR-222 were downregulated in individuals exposed to the A/H1N1 virus. Significant correlations (p<0.05) between circulating levels of miR-150 with IL-1ra, IL-2, IL-6, CXCL8, IFN-γ, CXCL10 and G-CSF were detected, particularly in critically ill patients. CONCLUSION: The up-regulation of miR-150 is associated with poorer outcomes of A/H1N1 infection. The differential expression of miRNAs related with immune processes in severe A/H1N1 disease supports the potential role of these miRNAs as biomarkers of disease progression.
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Biomarcadores/sangre , Subtipo H1N1 del Virus de la Influenza A/genética , Gripe Humana/genética , MicroARNs/genética , Índice de Severidad de la Enfermedad , Adulto , Estudios de Casos y Controles , Células Cultivadas , Citocinas/sangre , Ensayo de Inmunoadsorción Enzimática , Femenino , Perfilación de la Expresión Génica , Humanos , Gripe Humana/sangre , Gripe Humana/virología , Masculino , MicroARNs/sangre , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
INTRODUCTION: Surfactant protein D (SP-D) plays an important role in the innate responses against pathogens and its production is altered in lung disorders. METHODS: We studied the circulating levels of SP-D in 37 patients with acute respiratory distress syndrome due to the A/H1N1 virus infection and in 40 healthy controls. Cox logistic regression models were constructed to explore the association of SP-D levels and risk of death. RESULTS: Mortality rate after a 28-day was 32.42 %. Significant higher levels of SP-D were detected in A/H1N1 patients with fatal outcome (p < 0.05). After adjusting for confounding variables, levels of SP-D ≥250 ng/mL were associated with increased the risk of death (HR = 8.27, 95 % CI 1.1-64.1, p = 0.043). CONCLUSIONS: Our results revealed that higher circulating levels of SP-D are associated with higher mortality risk in critically ill A/H1N1 patients. SP-D might be a predictive factor of poor outcomes in viral pneumonia.
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Subtipo H1N1 del Virus de la Influenza A/patogenicidad , Gripe Humana/diagnóstico , Neumonía Viral/diagnóstico , Proteína D Asociada a Surfactante Pulmonar/sangre , Síndrome de Dificultad Respiratoria/diagnóstico , Adulto , Biomarcadores/sangre , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , Enfermedad Crítica , Femenino , Mortalidad Hospitalaria , Humanos , Gripe Humana/sangre , Gripe Humana/mortalidad , Gripe Humana/terapia , Gripe Humana/virología , Estimación de Kaplan-Meier , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Neumonía Viral/sangre , Neumonía Viral/mortalidad , Neumonía Viral/terapia , Neumonía Viral/virología , Pronóstico , Modelos de Riesgos Proporcionales , Síndrome de Dificultad Respiratoria/sangre , Síndrome de Dificultad Respiratoria/mortalidad , Síndrome de Dificultad Respiratoria/terapia , Síndrome de Dificultad Respiratoria/virología , Factores de Riesgo , Factores de Tiempo , Regulación hacia ArribaRESUMEN
BACKGROUND: The obesity has been shown to increase the severity of A/H1N1 infection and the development of acute respiratory distress syndrome (ARDS) and organ involvement. METHODS: Circulating levels of C-peptide, insulin, glucagon, leptin, acute phase reactants (procalcitonin, C-reactive protein, tissue plasminogen activator, and serum amyloids A and P), were measured in samples from 32 critically ill patients with A/H1N1 virus infection, 17 of whom had ARDS complicated by acute kidney injury (AKI) and 15 of whom had ARDS but did not develop AKI. RESULTS: Patients with ARDS and AKI (ARDS/AKI) had higher BMI and higher levels of C-peptide, insulin, leptin, procalcitonin and serum amyloid A compared to those ARDS patient who did not develop AKI. Adjusting for confounding variables using logistic regression analysis, higher levels of C-peptide (>0.75 ng/mL) (OR=64.8, 95% CI = 2.1-1980, p = 0.0006) and BMI>30 Kg/m(2) (OR = 42.0, 95% CI = 1.2-1478, p = 0.04) were significantly associated with the development of AKI in ARDS patients. CONCLUSION: High levels of C-peptide and BMI>30 kg/m(2) were associated with the development of AKI in ARDS patients due to A/H1N1 infection. These metabolic/obesity indicators, together with the profiles of pro-inflammatory acute phase proteins, may be important links between obesity and poor outcomes in A/H1N1 09 infection.
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Lesión Renal Aguda/virología , Gripe Humana/complicaciones , Obesidad/complicaciones , Síndrome de Dificultad Respiratoria/virología , Lesión Renal Aguda/metabolismo , Adulto , Enfermedad Crítica , Femenino , Humanos , Inflamación/metabolismo , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/metabolismo , Masculino , Persona de Mediana Edad , Síndrome de Dificultad Respiratoria/metabolismoRESUMEN
In vitro induced T regulatory cells (iTregs) are promising for addressing inflammation-driven diseases. However, current protocols for the generation and expansion of iTregs fail to induce extensive demethylation of the Treg-specific demethylated region (TSDR) within the FOXP3 gene, recognized as the master regulator for regulatory T cells (Tregs). This deficiency results in the rapid loss of Foxp3 expression and an unstable regulatory phenotype. Nevertheless, inhibition of STAT6 signaling effectively stabilizes Foxp3 expression in iTregs. Thus, this study aimed to develop a protocol combining epigenetic editing with STAT6 deficiency to improve iTregs' ability to maintain stable suppressive function and a functional phenotype. Our findings demonstrate that the combination of STAT6 deficiency (STAT6-/-) with targeted demethylation of the TSDR using a CRISPR-TET1 tool leads to extensive demethylation of FOXP3-TSDR. Demethylation in STAT6-/- iTregs was associated with enhanced expression of Foxp3 and suppressive markers such as CTLA-4, PD-1, IL-10, and TGF-ß. Furthermore, the edited STAT6-/- iTregs exhibited an increased capacity to suppress CD8+ and CD4+ lymphocytes and could more efficiently impair Th1-signature gene expression compared to conventional iTregs. In conclusion, the deactivation of STAT6 and TSDR-targeted demethylation via CRISPR-TET1 is sufficient to induce iTregs with heightened stability and increased suppressive capacity, offering potential applications against inflammatory and autoimmune diseases.
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PTP1B plays a key role in developing different types of cancer. However, the molecular mechanism underlying this effect is unclear. To identify molecular targets of PTP1B that mediate its role in tumorigenesis, we undertook a SILAC-based phosphoproteomic approach, which allowed us to identify Cdk3 as a novel PTP1B substrate. Substrate trapping experiments and docking studies revealed stable interactions between the PTP1B catalytic domain and Cdk3. In addition, we observed that PTP1B dephosphorylates Cdk3 at tyrosine residue 15 in vitro and interacts with it in human glioblastoma cells. Next, we found that pharmacological inhibition of PTP1B or its depletion with siRNA leads to cell cycle arrest with diminished activity of Cdk3, hypophosphorylation of Rb, and the downregulation of E2F target genes Cdk1, Cyclin A, and Cyclin E1. Finally, we observed that the expression of a constitutively active Cdk3 mutant bypasses the requirement of PTP1B for cell cycle progression and expression of E2F target genes. These data delineate a novel signaling pathway from PTP1B to Cdk3 required for efficient cell cycle progression in an Rb-E2F dependent manner in human GB cells.
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Glioblastoma , Humanos , Glioblastoma/genética , División Celular , Transducción de Señal , Puntos de Control del Ciclo Celular , Ciclo Celular/fisiología , Proteína Tirosina Fosfatasa no Receptora Tipo 1/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 1/metabolismoRESUMEN
Background: The SARS-CoV-2 virus has caused unprecedented mortality since its emergence in late 2019. The continuous evolution of the viral genome through the concerted action of mutational forces has produced distinct variants that became dominant, challenging human immunity and vaccine development. Aim and methods: In this work, through an integrative genomic approach, we describe the molecular transition of SARS-CoV-2 by analyzing the viral whole genome sequences from 50 critical COVID-19 patients recruited during the first year of the pandemic in Mexico City. Results: Our results revealed differential levels of the evolutionary forces across the genome and specific mutational processes that have shaped the first two epidemiological waves of the pandemic in Mexico. Through phylogenetic analyses, we observed a genomic transition in the circulating SARS-CoV-2 genomes from several lineages prevalent in the first wave to a dominance of the B.1.1.519 variant (defined by T478K, P681H, and T732A mutations in the spike protein) in the second wave. Conclusion: This work contributes to a better understanding of the evolutionary dynamics and selective pressures that act at the genomic level, the prediction of more accurate variants of clinical significance, and a better comprehension of the molecular mechanisms driving the evolution of SARS-CoV-2 to improve vaccine and drug development.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiología , Pandemias , México/epidemiología , Filogenia , Genoma Viral , MutaciónRESUMEN
The combination of metformin and TKIs for non-small cell lung cancer has been proposed as a strategy to overcome resistance of neoplastic cells induced by several molecular mechanisms. This study sought to investigate the effects of a second generation TKI afatinib, metformin, or their combination on three adenocarcinoma lung cancer cell lines with different EGFRmutation status. A549, H1975, and HCC827 cell lines were treated with afatinib, metformin, and their combination for 72 h. Afterwards, several parameters were assessed including cytotoxicity, interactions, apoptosis, and EGFR protein levels at the cell membrane and several glycolytic, oxidative phosphorylation (OXPHOS), and EMT expression markers. All cell lines showed additive to synergic interactions for the induction of cytotoxicity caused by the tested combination, as well as an improved pro-apoptotic effect. This effect was accompanied by downregulation of glycolytic, EMT markers, a significant decrease in glucose uptake, extracellular lactate, and a tendency towards increased OXPHOS subunits expression. Interestingly, we observed a better response to the combined therapy in lung cancer cell lines A549 and H1975, which normally have low affinity for TKI treatment. Findings from this study suggest a sensitization to afatinib therapy by metformin in TKI-resistant lung cancer cells, as well as a reduction in cellular glycolytic phenotype.
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Metformin has been under basic and clinical study as an oncological repurposing pharmacological agent for several years, stemming from observational studies which consistently evidenced that subjects who were treated with metformin had a reduced risk for development of cancer throughout their lives, as well as improved survival outcomes when diagnosed with neoplastic diseases. As a result, several basic science studies have attempted to dissect the relationship between metformin's metabolic mechanism of action and antineoplastic cellular signaling pathways. Evidence in this regard was compelling enough that a myriad of randomized clinical trials was planned and conducted in order to establish the effect of metformin treatment for patients with diverse neoplasms, including lung cancer. As with most novel antineoplastic agents, early results from these studies have been mostly discouraging, though a recent analysis that incorporated body mass index may provide significant information regarding which patient subgroups might derive the most benefit from the addition of metformin to their anticancer treatment. Much in line with the current pipeline for anticancer agents, it appears that the benefit of metformin may be circumscribed to a specific patient subgroup. If so, addition of metformin to antineoplastic agents could prove one of the most cost-effective interventions proposed in the context of precision oncology. Currently published reviews mostly rely on a widely questioned mechanism of action by metformin, which fails to consider the differential effects of the drug in lean vs. obese subjects. In this review, we analyze the pre-clinical and clinical information available to date regarding the use of metformin in various subtypes of lung cancer and, further, we present evidence as to the differential metabolic effects of metformin in lean and obese subjects where, paradoxically, the obese subjects have reported more benefit with the addition of metformin treatment. The novel mechanisms of action described for this biguanide may explain the different results observed in clinical trials published in the last decade. Lastly, we present novel hypothesis regarding potential biomarkers to identify who might reap benefit from this intervention, including the role of prolyl hydroxylase domain 3 (PHD3) expression to modify metabolic phenotypes in malignant diseases.
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BACKGROUND: Mesenchyme homeobox-2 (MEOX2)-mediated regulation of glioma-associated oncogene-1 (GLI1) has been associated with poor overall survival, conferring chemoresistance in lung cancer. However, the role of MEOX2/GLI1 in resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs)-based therapy remains unexplored in human lung cancer. METHODS: Functional assays using genetic silencing strategy by short hairpin RNAs, as well as cytotoxic (tetrazolium dye MTT) and clonogenic assays, were performed to evaluate MEOX2/GLI1-induced malignancy capacity in lung cancer cells. Further analysis performed includes western blot, qPCR and ChIP-qPCR assays to identify whether MEOX2/GLI1 promote EGFR/AKT/ERK activation, as well as EGFR overexpression through epigenetic mechanisms. Finally, preclinical tumour progression in vivo and progression-free disease interval analyses in patients treated with EGFR-TKI were included. RESULTS: Overexpressed MEOX2/GLI1 in both EGFR wild-type and EGFR/KRAS-mutated lung cancer cells were detected and involved in the activation/expression of EGFR/AKT/ERK biomarkers. In addition, MEOX2/GLI1 was shown to be involved in the increased proliferation of tumour cells and resistance capacity to cisplatin, EGFR-TKIs (erlotinib and AZD9291 'osimertinib'), AZD8542-SMO, and AZD6244-MEKK1/2. In addition, we identified that MEOX2/GLI1 promote lung tumour cells progression in vivo and are clinically associated with poorer progression-free disease intervals. Finally, both MEOX2 and GLI1 were detected to be epigenetically involved in EGFR expression by reducing both repressive markers polycomb-EZH2 and histone H3K27me3, but, particularly, increasing an activated histone profile H3K27Ac/H3K4me3 at EGFR-gene enhancer-promoter sequences that probably representing a novel EGFR-TKI-based therapy resistance mechanism. CONCLUSION: MEOX2/GLI1 promote resistance to cisplatin and EGFR-TKI-based therapy in lung cancer cells, modulating EGFR/AKT/ERK signalling pathway activation, as well as inducing an aberrant epigenetic modulation of the EGFR-gene expression in human lung cancer.