RESUMO
Older patients with cancer often receive treatment regimens based on their age without considering other objective factors that may influence outcomes. Assessment of frailty can identify older patients who are robust and therefore more likely to benefit from intensive treatment, or conversely, frail and might instead be offered alternative approaches. However, such assessment requires specialised training and dedicated clinical resources. Alternative quantitative biomarkers associated with frailty are lacking. Here, we asked if expression signatures of 74 immune cell, ageing, and senescence-related messenger RNAs in purified peripheral blood T cells could identify associations with clinical frailty in patients with haematological malignancies. We studied 69 patients between the ages of 36 and 92 years (median 76 years) with leukaemia, lymphoma, or multiple myeloma, across two institutions. Expression of four genes (aryl hydrocarbon receptor [AHR], CD27, CD28, and interleukin-2 receptor subunit alpha [IL2RA; CD25]) in T cells was associated with frailty, independent of age. An expression-based regression model had 76% sensitivity and 90% specificity to assign a patient as robust. These data identify measurable peripheral blood correlates of clinical frailty and suggest biomarkers for future prospective assessment.
Assuntos
Fragilidade , Neoplasias Hematológicas , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Antígenos CD28/metabolismo , Idoso Fragilizado , Expressão Gênica , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/metabolismo , Humanos , Pessoa de Meia-Idade , Receptores de Hidrocarboneto Arílico/metabolismo , Linfócitos T/metabolismoRESUMO
Regulation of nuclear transport is an essential component of apoptosis. As chemotherapy induced cell death progresses, nuclear transport and the nuclear pore complex (NPC) are slowly disrupted and dismantled. 5-Fluorouracil (5-FU) and the camptothecin derivatives irinotecan and topotecan, are linked to altered nuclear transport of specific proteins; however, their general effects on the NPC and transport during apoptosis have not been characterized. We demonstrate that 5-FU, but not topotecan, increases NPC permeability, and disrupts Ran-mediated nuclear transport before the disruption of the NPC. This increased permeability is dependent on increased cellular calcium, as the Ca2+ chelator BAPTA-AM, abolishes the effect. Furthermore, increased calcium alone was sufficient to disrupt the Ran gradient. Combination treatments of 5-FU with topotecan or irinotecan, similarly disrupted nuclear transport before disassembly of the NPC. In both single and combination treatments nuclear transport was disrupted before caspase 9 activation, indicating that 5-FU induces an early caspase-independent increase in NPC permeability and alteration of nuclear transport. Because Crm1-mediated nuclear export of tumor suppressors is linked to drug resistance we also examined the effect of 5-FU on the nuclear export of a specific target, topoisomerase. 5-FU treatment led to accumulation of topoisomerase in the nucleus and recovered the loss nuclear topoisomerase induced by irinotecan or topotecan, a known cause of drug resistance. Furthermore, 5-FU retains its ability to cause nuclear accumulation of p53 in the presence of irinotecan or topotecan. Our results reveal a new mechanism of action for these therapeutics during apoptosis, opening the door to other potential combination chemotherapies that employ 5-FU as a calcium mediated inhibitor of Crm1-induced nuclear export of tumor suppressors.
Assuntos
Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Antimetabólitos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Cálcio/fisiologia , Fluoruracila/farmacologia , Poro Nuclear/efeitos dos fármacos , Camptotecina/análogos & derivados , Camptotecina/farmacologia , Caspases/metabolismo , Núcleo Celular/enzimologia , DNA Topoisomerases Tipo I/metabolismo , Interações Medicamentosas , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Células HeLa , Humanos , Irinotecano , Proteínas de Neoplasias/fisiologia , Permeabilidade , Topotecan/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Proteína ran de Ligação ao GTP/fisiologiaRESUMO
Chromatin organization is a highly orchestrated process that influences gene expression, in part by modulating access of regulatory factors to DNA and nucleosomes. Here, we report that the chromatin accessibility regulator HMGN1, a target of recurrent DNA copy gains in leukemia, controls myeloid differentiation. HMGN1 amplification is associated with increased accessibility, expression, and histone H3K27 acetylation of loci important for hematopoietic stem cells (HSCs) and leukemia, such as HoxA cluster genes. In vivo, HMGN1 overexpression is linked to decreased quiescence and increased HSC activity in bone marrow transplantation. HMGN1 overexpression also cooperates with the AML-ETO9a fusion oncoprotein to impair myeloid differentiation and enhance leukemia stem cell (LSC) activity. Inhibition of histone acetyltransferases CBP/p300 relieves the HMGN1-associated differentiation block. These data nominate factors that modulate chromatin accessibility as regulators of HSCs and LSCs, and suggest that targeting HMGN1 or its downstream effects on histone acetylation could be therapeutically active in AML.
Assuntos
Cromatina/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Acetilação , Animais , Diferenciação Celular , Sobrevivência Celular , Feminino , Proteína HMGN1/genética , Proteína HMGN1/metabolismo , Células-Tronco Hematopoéticas/citologia , Histonas/genética , Histonas/metabolismo , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismoRESUMO
Down syndrome (DS, trisomy 21) is associated with developmental abnormalities and increased leukemia risk. To reconcile chromatin alterations with transcriptome changes, we performed paired exogenous spike-in normalized RNA and chromatin immunoprecipitation sequencing in DS models. Absolute normalization unmasks global amplification of gene expression associated with trisomy 21. Overexpression of the nucleosome binding protein HMGN1 (encoded on chr21q22) recapitulates transcriptional changes seen with triplication of a Down syndrome critical region on distal chromosome 21, and HMGN1 is necessary for B cell phenotypes in DS models. Absolute exogenous-normalized chromatin immunoprecipitation sequencing (ChIP-Rx) also reveals a global increase in histone H3K27 acetylation caused by HMGN1. Transcriptional amplification downstream of HMGN1 is enriched for stage-specific programs of B cells and B cell acute lymphoblastic leukemia, dependent on the developmental cellular context. These data offer a mechanistic explanation for DS transcriptional patterns and suggest that further study of HMGN1 and RNA amplification in diverse DS phenotypes is warranted.