RESUMEN
Coronavirus disease 2019 (COVID-19) and influenza are respiratory illnesses caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses, respectively. Both diseases share symptoms and clinical risk factors1, but the extent to which these conditions have a common genetic etiology is unknown. This is partly because host genetic risk factors are well characterized for COVID-19 but not for influenza, with the largest published genome-wide association studies for these conditions including >2 million individuals2 and about 1,000 individuals3-6, respectively. Shared genetic risk factors could point to targets to prevent or treat both infections. Through a genetic study of 18,334 cases with a positive test for influenza and 276,295 controls, we show that published COVID-19 risk variants are not associated with influenza. Furthermore, we discovered and replicated an association between influenza infection and noncoding variants in B3GALT5 and ST6GAL1, neither of which was associated with COVID-19. In vitro small interfering RNA knockdown of ST6GAL1-an enzyme that adds sialic acid to the cell surface, which is used for viral entry-reduced influenza infectivity by 57%. These results mirror the observation that variants that downregulate ACE2, the SARS-CoV-2 receptor, protect against COVID-19 (ref. 7). Collectively, these findings highlight downregulation of key cell surface receptors used for viral entry as treatment opportunities to prevent COVID-19 and influenza.
Asunto(s)
COVID-19 , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Gripe Humana , SARS-CoV-2 , Humanos , Gripe Humana/genética , Gripe Humana/epidemiología , Gripe Humana/virología , COVID-19/genética , COVID-19/virología , Factores de Riesgo , SARS-CoV-2/genética , Masculino , Femenino , Polimorfismo de Nucleótido Simple , Estudios de Casos y Controles , Persona de Mediana EdadRESUMEN
We multiply ascertained the BRCA1 pathogenic missense variant c.5207T > C; p.Val1736Ala (V1736A) in clinical investigation of breast and ovarian cancer families from Orkney in the Northern Isles of Scotland, UK. We sought to investigate the frequency and clinical relevance of this variant in those of Orcadian ancestry as an exemplar of the value of population cohorts in clinical care, especially in isolated populations. Oral history and birth, marriage and death registrations indicated genealogical linkage of the clinical cases to ancestors from the Isle of Westray, Orkney. Further clinical cases were identified through targeted testing for V1736A in women of Orcadian ancestry attending National Health Service (NHS) genetic clinics for breast and ovarian cancer family risk assessments. The variant segregates with female breast and ovarian cancer in clinically ascertained cases. Separately, exome sequence data from 2088 volunteer participants with three or more Orcadian grandparents, in the ORCADES research cohort, was interrogated to estimate the population prevalence of V1736A in Orcadians. The effects of the variant were assessed using Electronic Health Record (EHR) linkage. Twenty out of 2088 ORCADES research volunteers (~1%) carry V1736A, with a common haplotype around the variant. This allele frequency is ~480-fold higher than in UK Biobank participants. Cost-effectiveness of population screening for BRCA1 founder pathogenic variants has been demonstrated at a carrier frequency below the ~1% observed here. Thus we suggest that Orcadian women should be offered testing for the BRCA1 V1736A founder pathogenic variant, starting with those with known Westray ancestry.
Asunto(s)
Neoplasias de la Mama , Neoplasias Ováricas , Humanos , Femenino , Medicina Estatal , Proteína BRCA1/genética , Neoplasias Ováricas/epidemiología , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Frecuencia de los Genes , Haplotipos , Escocia/epidemiología , Neoplasias de la Mama/genética , Predisposición Genética a la Enfermedad , Proteína BRCA2/genética , Pruebas GenéticasRESUMEN
Increased blood levels of low-density lipoprotein cholesterol (LDL-C) and fibrinogen are independent risk factors for cardiovascular disease. We identified associations between an Amish-enriched missense variant (p.Asn352Ser) in a functional domain of beta-1,4-galactosyltransferase 1 (B4GALT1) and 13.9 milligrams per deciliter lower LDL-C (P = 4.1 × 1019) and 29 milligrams per deciliter lower plasma fibrinogen (P = 1.3 × 105). B4GALT1 genebased analysis in 544,955 subjects showed an association with decreased coronary artery disease (odds ratio = 0.64, P = 0.006). The mutant protein had 50% lower galactosyltransferase activity compared with the wild-type protein. N-linked glycan profiling of human serum found serine 352 allele to be associated with decreased galactosylation and sialylation of apolipoprotein B100, fibrinogen, immunoglobulin G, and transferrin. B4galt1 353Ser knock-in mice showed decreases in LDL-C and fibrinogen. Our findings suggest that targeted modulation of protein galactosylation may represent a therapeutic approach to decreasing cardiovascular disease.
Asunto(s)
LDL-Colesterol/sangre , Fibrinógeno/análisis , Galactosiltransferasas/genética , Mutación Missense , Animales , Enfermedad de la Arteria Coronaria/genética , Enfermedad de la Arteria Coronaria/prevención & control , Femenino , Galactosa/metabolismo , Galactosiltransferasas/metabolismo , Técnicas de Sustitución del Gen , Técnicas de Silenciamiento del Gen , Glicoproteínas/sangre , Glicosilación , Humanos , Hígado/enzimología , Masculino , Ratones , Ácido N-Acetilneuramínico/metabolismo , Polisacáridos/sangre , Secuenciación Completa del GenomaRESUMEN
Activating mutations in the cytosolic 5'-nucleotidase II gene NT5C2 drive resistance to 6-mercaptopurine in acute lymphoblastic leukemia. Here we demonstrate that constitutively active NT5C2 mutations K359Q and L375F reconfigure the catalytic center for substrate access and catalysis in the absence of allosteric activator. In contrast, most relapse-associated mutations, which involve the arm segment and residues along the surface of the inter-monomeric cavity, disrupt a built-in switch-off mechanism responsible for turning off NT5C2. In addition, we show that the C-terminal acidic tail lost in the Q523X mutation functions to restrain NT5C2 activation. These results uncover dynamic mechanisms of enzyme regulation targeted by chemotherapy resistance-driving NT5C2 mutations, with important implications for the development of NT5C2 inhibitor therapies.
Asunto(s)
5'-Nucleotidasa/genética , Antimetabolitos Antineoplásicos/farmacología , Resistencia a Antineoplásicos/genética , Mercaptopurina/farmacología , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , 5'-Nucleotidasa/química , 5'-Nucleotidasa/metabolismo , Regulación Alostérica , Animales , Dominio Catalítico , Regulación Leucémica de la Expresión Génica , Células HEK293 , Humanos , Células Jurkat , Ratones Endogámicos C57BL , Modelos Moleculares , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimología , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Conformación Proteica en Hélice alfa , Recurrencia , Relación Estructura-ActividadRESUMEN
Relapsed acute lymphoblastic leukaemia (ALL) is associated with resistance to chemotherapy and poor prognosis. Gain-of-function mutations in the 5'-nucleotidase, cytosolic II (NT5C2) gene induce resistance to 6-mercaptopurine and are selectively present in relapsed ALL. Yet, the mechanisms involved in NT5C2 mutation-driven clonal evolution during the initiation of leukaemia, disease progression and relapse remain unknown. Here we use a conditional-and-inducible leukaemia model to demonstrate that expression of NT5C2(R367Q), a highly prevalent relapsed-ALL NT5C2 mutation, induces resistance to chemotherapy with 6-mercaptopurine at the cost of impaired leukaemia cell growth and leukaemia-initiating cell activity. The loss-of-fitness phenotype of NT5C2+/R367Q mutant cells is associated with excess export of purines to the extracellular space and depletion of the intracellular purine-nucleotide pool. Consequently, blocking guanosine synthesis by inhibition of inosine-5'-monophosphate dehydrogenase (IMPDH) induced increased cytotoxicity against NT5C2-mutant leukaemia lymphoblasts. These results identify the fitness cost of NT5C2 mutation and resistance to chemotherapy as key evolutionary drivers that shape clonal evolution in relapsed ALL and support a role for IMPDH inhibition in the treatment of ALL.
Asunto(s)
5'-Nucleotidasa/genética , 5'-Nucleotidasa/metabolismo , Evolución Clonal , Resistencia a Antineoplásicos/genética , Mutación/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Animales , Proliferación Celular , Modelos Animales de Enfermedad , Femenino , Mutación con Ganancia de Función/genética , Guanosina/biosíntesis , Células HEK293 , Humanos , IMP Deshidrogenasa/antagonistas & inhibidores , IMP Deshidrogenasa/metabolismo , Masculino , Mercaptopurina/farmacología , Mercaptopurina/uso terapéutico , Ratones , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Purinas/metabolismo , Receptor Notch1/metabolismo , Recurrencia , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Although multiagent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die because of chemorefractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape at relapse in pediatric ALL cases. These analyses identified numerous relapse-associated mutated genes intertwined in chemotherapy resistance-related protein complexes. In this context, RAS-MAPK pathway-activating mutations in the neuroblastoma RAS viral oncogene homolog (NRAS), kirsten rat sarcoma viral oncogene homolog (KRAS), and protein tyrosine phosphatase, nonreceptor type 11 (PTPN11) genes were present in 24 of 55 (44%) cases in our series. Interestingly, some leukemias showed retention or emergence of RAS mutant clones at relapse, whereas in others RAS mutant clones present at diagnosis were replaced by RAS wild-type populations, supporting a role for both positive and negative selection evolutionary pressures in clonal evolution of RAS-mutant leukemia. Consistently, functional dissection of mouse and human wild-type and mutant RAS isogenic leukemia cells demonstrated induction of methotrexate resistance but also improved the response to vincristine in mutant RAS-expressing lymphoblasts. These results highlight the central role of chemotherapy-driven selection as a central mechanism of leukemia clonal evolution in relapsed ALL, and demonstrate a previously unrecognized dual role of RAS mutations as drivers of both sensitivity and resistance to chemotherapy.
Asunto(s)
Evolución Clonal/genética , Genes ras , Mutación/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Secuencia de Bases , Línea Celular Tumoral , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Humanos , Metotrexato/farmacología , Metotrexato/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Vincristina/farmacología , Vincristina/uso terapéuticoRESUMEN
Relapse is the leading cause of mortality in children with acute lymphoblastic leukemia (ALL). Among chemotherapeutics, thiopurines are key drugs in ALL combination therapy. Using whole-exome sequencing, we identified relapse-specific mutations in the phosphoribosyl pyrophosphate synthetase 1 gene (PRPS1), which encodes a rate-limiting purine biosynthesis enzyme, in 24/358 (6.7%) relapsed childhood B cell ALL (B-ALL) cases. All individuals who harbored PRPS1 mutations relapsed early during treatment, and mutated ALL clones expanded exponentially before clinical relapse. Our functional analyses of PRPS1 mutants uncovered a new chemotherapy-resistance mechanism involving reduced feedback inhibition of de novo purine biosynthesis and competitive inhibition of thiopurine activation. Notably, the de novo purine synthesis inhibitor lometrexol effectively abrogated PRPS1 mutant-driven drug resistance. These results highlight the importance of constitutive activation of the de novo purine synthesis pathway in thiopurine resistance, and they offer therapeutic strategies for the treatment of relapsed and thiopurine-resistant ALL.
Asunto(s)
Retroalimentación Fisiológica/efectos de los fármacos , Leucemia de Células B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Ribosa-Fosfato Pirofosfoquinasa/genética , Adolescente , Niño , Preescolar , Exoma/genética , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Lactante , Leucemia de Células B/tratamiento farmacológico , Leucemia de Células B/patología , Masculino , Mercaptopurina/administración & dosificación , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Purinas/biosíntesis , Recurrencia , Ribosa-Fosfato Pirofosfoquinasa/química , Tetrahidrofolatos/administración & dosificaciónRESUMEN
Acute lymphoblastic leukemia (ALL) is an aggressive hematological tumor resulting from the malignant transformation of lymphoid progenitors. Despite intensive chemotherapy, 20% of pediatric patients and over 50% of adult patients with ALL do not achieve a complete remission or relapse after intensified chemotherapy, making disease relapse and resistance to therapy the most substantial challenge in the treatment of this disease. Using whole-exome sequencing, we identify mutations in the cytosolic 5'-nucleotidase II gene (NT5C2), which encodes a 5'-nucleotidase enzyme that is responsible for the inactivation of nucleoside-analog chemotherapy drugs, in 20/103 (19%) relapse T cell ALLs and 1/35 (3%) relapse B-precursor ALLs. NT5C2 mutant proteins show increased nucleotidase activity in vitro and conferred resistance to chemotherapy with 6-mercaptopurine and 6-thioguanine when expressed in ALL lymphoblasts. These results support a prominent role for activating mutations in NT5C2 and increased nucleoside-analog metabolism in disease progression and chemotherapy resistance in ALL.
Asunto(s)
5'-Nucleotidasa/genética , Antineoplásicos/uso terapéutico , Resistencia a Antineoplásicos/genética , Mercaptopurina/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , 5'-Nucleotidasa/metabolismo , Arabinonucleósidos/farmacología , Arabinonucleósidos/uso terapéutico , Secuencia de Bases , Línea Celular , Células HEK293 , Humanos , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Recurrencia , Análisis de Secuencia de ADN , Tioguanina/uso terapéuticoRESUMEN
NOTCH1 receptor signaling plays a central role in T-cell lineage specification and in supporting the growth and proliferation of immature T-cell progenitors in the thymus during lymphoid development. In T-cell acute lymphoblastic leukemia (T-ALL), a tumor resulting from the malignant transformation of T-cell progenitors, aberrant and constitutively active NOTCH1 signaling triggered by activating mutations in the NOTCH1 gene contributes to oncogenic transformation and is a hallmark of this disease. Most notably, small molecule γ-secretase inhibitors (GSIs) can effectively block NOTCH1 signaling in T-ALL, and could be exploited as a targeted therapy in this disease. In addition, a number of emerging anti-NOTCH therapeutic strategies including anti-NOTCH1 inhibitory antibodies, small peptide inhibitors of NOTCH signaling and combination therapies with GSIs and glucocorticoids, have recently been proposed. Finally, the identification of NOTCH1 mutations in solid tumors and chronic lymphocytic leukemias has increased even further the clinical relevance of NOTCH signaling as a therapeutic target in human cancer. Here we review our current understanding of NOTCH1-induced transformation, the mechanisms of action of oncogenic NOTCH1 in T-ALL and the therapeutic and prognostic implications of NOTCH1 mutations in T-ALL.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Regulación Leucémica de la Expresión Génica/inmunología , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Receptor Notch1/antagonistas & inhibidores , Transducción de Señal/inmunología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Anticuerpos/uso terapéutico , Transformación Celular Neoplásica/efectos de los fármacos , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/inmunología , Quimioterapia Combinada , Inhibidores Enzimáticos/uso terapéutico , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Humanos , Terapia Molecular Dirigida , Mutación , Péptidos/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/inmunología , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Receptor Notch1/genética , Receptor Notch1/inmunología , Transducción de Señal/efectos de los fármacosRESUMEN
Lamina-associated polypeptide 2 alpha (LAP2α) plays a role in maintaining nuclear structure, in nuclear assembly/disassembly, and in transcriptional regulation. Elevated LAP2α mRNA expression has been previously reported to associate with certain cancer types. The aim of this study was to investigate LAP2α expression in cervical cancer and transformed cells and to identify factors that associate with its differential expression. LAP2α expression was found to be elevated in cervical cancer tissue by microarray, qRT-PCR, and immunofluorescence analyses. LAP2α also showed elevated expression in cervical cancer cell lines and in transformed fibroblasts compared with normal cells. To determine factors associated with elevated LAP2α in cervical cancer, the effect of inhibiting HPV E7 and E6 oncoproteins was investigated. E7 inhibition resulted in a decrease in phosphorylated Rb and an associated decrease in LAP2α, suggesting a role for E2F in regulating LAP2α expression. This finding was confirmed by inhibiting DP1, a co-activator of E2F, which resulted in decreased LAP2α levels. Inhibition of E6 resulted in elevated p53 and an associated decrease in LAP2α, suggesting that p53 associates with the negative regulation of LAP2α expression. This hypothesis was tested by inhibiting p53 in normal cells, and a resultant increase in LAP2α expression was observed. In conclusion, this study provides evidence for elevated LAP2α expression in cervical cancer and suggests that E2F and p53 activities associate with the positive and negative regulation of LAP2α expression, respectively.