RESUMEN
Internal tandem duplications (ITD) in the Fms-related tyrosine kinase 3 receptor (FLT3) are associated with a dismal prognosis in acute myeloid leukemia (AML). FLT3 inhibitors such as sorafenib may improve outcome, but only few patients display long-term responses, prompting the search for underlying resistance mechanisms and therapeutic strategies to overcome them. Here we identified that the nuclear factor of activated T cells, NFATc1, is frequently overexpressed in FLT3-ITD-positive (FLT3-ITD+) AML. NFATc1 knockdown using inducible short hairpin RNA or pharmacological NFAT inhibition with cyclosporine A (CsA) or VIVIT significantly augmented sorafenib-induced apoptosis of FLT3-ITD+ cells. CsA also potently overcame sorafenib resistance in FLT3-ITD+ cell lines and primary AML. Vice versa, de novo expression of a constitutively nuclear NFATc1-mutant mediated instant and robust sorafenib resistance in vitro. Intriguingly, FLT3-ITD+ AML patients (n=26) who received CsA as part of their rescue chemotherapy displayed a superior outcome when compared with wild-type FLT3 (FLT3-WT) AML patients. Our data unveil NFATc1 as a novel mediator of sorafenib resistance in FLT3-ITD+ AML. CsA counteracts sorafenib resistance and may improve treatment outcome in AML by means of inhibiting NFAT.
Asunto(s)
Resistencia a Antineoplásicos/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Factores de Transcripción NFATC/metabolismo , Recurrencia Local de Neoplasia/tratamiento farmacológico , Niacinamida/análogos & derivados , Compuestos de Fenilurea/farmacología , Secuencias Repetidas en Tándem/genética , Tirosina Quinasa 3 Similar a fms/metabolismo , Apoptosis/efectos de los fármacos , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Western Blotting , Proliferación Celular/efectos de los fármacos , Ciclosporina/farmacología , Citometría de Flujo , Perfilación de la Expresión Génica , Humanos , Técnicas para Inmunoenzimas , Inmunosupresores/farmacología , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/mortalidad , Leucemia Mieloide Aguda/patología , Mutación/genética , Factores de Transcripción NFATC/antagonistas & inhibidores , Factores de Transcripción NFATC/genética , Recurrencia Local de Neoplasia/metabolismo , Recurrencia Local de Neoplasia/mortalidad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Niacinamida/farmacología , Análisis de Secuencia por Matrices de Oligonucleótidos , Pronóstico , Inhibidores de Proteínas Quinasas/farmacología , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sorafenib , Tasa de Supervivencia , Células Tumorales Cultivadas , Tirosina Quinasa 3 Similar a fms/genéticaRESUMEN
The human oral microbiome is comprised of approximately 800 different bacterial species many of which are as yet uncultivated. Their dynamics and variability in relation to health and disease are still poorly understood. Here we tested the hypothesis that the emergence of stress-induced periodontal diseases is predictable based on the composition of the initial microbiota. As a model, we analysed 58 individuals performing a challenging expedition (exposure to various stress-factors due to changes in diet, hygiene, temperature, physical and mental stress) in remote regions of the Himalayans (Annapurna Himal). Plaque samples were taken at start (Bhulbule) and destination (3000 meter difference in altitude) seven days later (Manang). Twenty-eight individuals remained symptom-free (Group I) while 30 participants developed periodontal problems, mostly gingivitis (Group II). The microbiota was monitored via T-RFLP-analysis of amplified 16S rRNA genes directly from the plaque samples. Based on the Additive-Main-Effects-Multiplicative-Interactions-model (AMMI) using the T-Rex software variation from T-RF main effects was at least 95%, indicating that most variation was due to inherent differences in microbial communities among individuals. However, an interaction signal up to 3% was consistently observed between groups I and II but not between the two time points of sampling regardless of selected analytical parameters. The data, supported by heterogeneity, diversity and similarity indices indicated marked differences between groups I and II already prior the onset of clinical symptoms. These differences may provide the basis for using ecological parameters of oral microbial communities as early diagnostic marker for the onset of oral disorders and infections.
