RESUMEN
Rituximab has been used to treat MS patients in Iceland for over a decade. However, long-term effect of rituximab on leukocyte populations has not yet been elucidated. By retrospective analysis of flow cytometric data from 349 patients visiting the neurological ward at The National University Hospital of Iceland from 2012 to 2023 for rituximab treatment, the long-term effect of rituximab and whether the effect was dose dependent (1000mg vs 500mg) was evaluated. No difference was detected in efficacy of B cell depletion in patients treated with 500mg as an initial dose of rituximab when compared to 1000mg. Long-term use of rituximab led to an increase in T cell count (p=0,0015) in patients receiving 3-8 doses of rituximab (1.5-8 years of treatment). The increase occurred in both CD4+ (p=0,0028) and CD8+ T cells (p=0,0015) and led to a decrease in the CD4/CD8 ratio (p=0,004). The most notable difference lies in reshaping the balance between näive and effector CD8+ T cells. The clinical implications of long-term treatment with rituximab and its effect on the T cell pool needs to be explored further. Since no difference in B cell depletion was detected between the two patient groups, 1000mg as an initial dose might be excessive, suggesting a personalized dosing regimen might have therapeutic and financial advantages.
Asunto(s)
Esclerosis Múltiple , Rituximab , Humanos , Rituximab/administración & dosificación , Rituximab/uso terapéutico , Rituximab/efectos adversos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Esclerosis Múltiple/tratamiento farmacológico , Esclerosis Múltiple/inmunología , Estudios Retrospectivos , Recuento de Linfocitos , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/uso terapéutico , Anciano , Relación CD4-CD8 , Linfocitos B/inmunología , Linfocitos B/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/efectos de los fármacosRESUMEN
Although expression quantitative trait loci (eQTLs) have been powerful in identifying susceptibility genes from genome-wide association study (GWAS) findings, most trait-associated loci are not explained by eQTLs alone. Alternative QTLs, including DNA methylation QTLs (meQTLs), are emerging, but cell-type-specific meQTLs using cells of disease origin have been lacking. Here, we established an meQTL dataset by using primary melanocytes from 106 individuals and identified 1,497,502 significant cis-meQTLs. Multi-QTL colocalization with meQTLs, eQTLs, and mRNA splice-junction QTLs from the same individuals together with imputed methylome-wide and transcriptome-wide association studies identified candidate susceptibility genes at 63% of melanoma GWAS loci. Among the three molecular QTLs, meQTLs were the single largest contributor. To compare melanocyte meQTLs with those from malignant melanomas, we performed meQTL analysis on skin cutaneous melanomas from The Cancer Genome Atlas (n = 444). A substantial proportion of meQTL probes (45.9%) in primary melanocytes is preserved in melanomas, while a smaller fraction of eQTL genes is preserved (12.7%). Integration of melanocyte multi-QTLs and melanoma meQTLs identified candidate susceptibility genes at 72% of melanoma GWAS loci. Beyond GWAS annotation, meQTL-eQTL colocalization in melanocytes suggested that 841 unique genes potentially share a causal variant with a nearby methylation probe in melanocytes. Finally, melanocyte trans-meQTLs identified a hotspot for rs12203592, a cis-eQTL of a transcription factor, IRF4, with 131 candidate target CpGs. Motif enrichment and IRF4 ChIP-seq analysis demonstrated that these target CpGs are enriched in IRF4 binding sites, suggesting an IRF4-mediated regulatory network. Our study highlights the utility of cell-type-specific meQTLs.
Asunto(s)
Redes Reguladoras de Genes , Factores Reguladores del Interferón/genética , Melanocitos/metabolismo , Melanoma/genética , Sitios de Carácter Cuantitativo , Neoplasias Cutáneas/genética , Alelos , Atlas como Asunto , Cromatina/química , Cromatina/metabolismo , Mapeo Cromosómico , Metilación de ADN , Regulación de la Expresión Génica , Predisposición Genética a la Enfermedad , Genoma Humano , Estudio de Asociación del Genoma Completo , Humanos , Recién Nacido , Factores Reguladores del Interferón/metabolismo , Masculino , Melanocitos/patología , Melanoma/metabolismo , Melanoma/patología , Cultivo Primario de Células , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patología , TranscriptomaRESUMEN
The microphthalmia-associated transcription factor (MITF) is a critical regulator of melanocyte development and differentiation. It also plays an important role in melanoma where it has been described as a molecular rheostat that, depending on activity levels, allows reversible switching between different cellular states. Here, we show that MITF directly represses the expression of genes associated with the extracellular matrix (ECM) and focal adhesion pathways in human melanoma cells as well as of regulators of epithelial-to-mesenchymal transition (EMT) such as CDH2, thus affecting cell morphology and cell-matrix interactions. Importantly, we show that these effects of MITF are reversible, as expected from the rheostat model. The number of focal adhesion points increased upon MITF knockdown, a feature observed in drug-resistant melanomas. Cells lacking MITF are similar to the cells of minimal residual disease observed in both human and zebrafish melanomas. Our results suggest that MITF plays a critical role as a repressor of gene expression and is actively involved in shaping the microenvironment of melanoma cells in a cell-autonomous manner.
Asunto(s)
Transición Epitelial-Mesenquimal , Matriz Extracelular/metabolismo , Adhesiones Focales/metabolismo , Factor de Transcripción Asociado a Microftalmía/genética , Línea Celular Tumoral , Humanos , Melanoma/metabolismo , Factor de Transcripción Asociado a Microftalmía/metabolismoRESUMEN
Metastatic malignant melanoma continues to be a challenging disease despite clinical translation of the comprehensive understanding of driver mutations and how melanoma cells evade immune attack. In Myc-driven lymphoma, efficacy of epigenetic inhibitors of the bromodomain and extra-terminal domain (BET) family of bromodomain proteins can be enhanced by combination therapy with inhibitors of the DNA damage response kinase ATR. Whether this combination is active in solid malignancies like melanoma, and how it relates to immune therapy, has not previously investigated. To test efficacy and molecular consequences of combination therapies cultured melanoma cells were used. To assess tumor responses to therapies in vivo we use patient-derived xenografts and B6 mice transplanted with B16F10 melanoma cells. Concomitant inhibition of BET proteins and ATR of cultured melanoma cells resulted in similar effects as recently shown in lymphoma, such as induction of apoptosis and p62, implicated in autophagy, senescence-associated secretory pathway and ER stress. In vivo, apoptosis and suppression of subcutaneous growth of patient-derived melanoma and B16F10 cells were observed. Our data suggest that ATRI/BETI combination therapies are effective in melanoma.
Asunto(s)
Antineoplásicos/uso terapéutico , Melanoma/tratamiento farmacológico , Proteínas/antagonistas & inhibidores , Proteínas/metabolismo , Quinolinas/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Autofagia/efectos de los fármacos , Autofagia/genética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Linfoma/tratamiento farmacológico , Linfoma/genética , Melanoma/genética , Ratones , Proteínas/genética , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genéticaRESUMEN
Cancers have dysfunctional redox regulation resulting in reactive oxygen species production, damaging both DNA and free dNTPs. The MTH1 protein sanitizes oxidized dNTP pools to prevent incorporation of damaged bases during DNA replication. Although MTH1 is non-essential in normal cells, we show that cancer cells require MTH1 activity to avoid incorporation of oxidized dNTPs, resulting in DNA damage and cell death. We validate MTH1 as an anticancer target in vivo and describe small molecules TH287 and TH588 as first-in-class nudix hydrolase family inhibitors that potently and selectively engage and inhibit the MTH1 protein in cells. Protein co-crystal structures demonstrate that the inhibitors bind in the active site of MTH1. The inhibitors cause incorporation of oxidized dNTPs in cancer cells, leading to DNA damage, cytotoxicity and therapeutic responses in patient-derived mouse xenografts. This study exemplifies the non-oncogene addiction concept for anticancer treatment and validates MTH1 as being cancer phenotypic lethal.