Ewing Sarcoma (EWS) is an aggressive bone and soft tissue tumor that mainly affects children, adolescents, and young adults. The standard therapy, including chemotherapy, surgery, and radiotherapy, ...has substantially improved the survival of EWS patients with localized disease. Unfortunately, this multimodal treatment remains elusive in clinics for those patients with recurrent or metastatic disease who have an unfavorable prognosis. Consistently, there is an urgent need to find new strategies for patients that fail to respond to standard therapies. In this regard, in the last decade, treatments targeting epigenetic dependencies in tumor cells and the immune system have emerged into the clinical scenario. Additionally, recent advances in nanomedicine provide novel delivery drug systems, which may address challenges such as side effects and toxicity. Therefore, therapeutic strategies stemming from epigenetics, immunology, and nanomedicine yield promising alternatives for treating these patients. In this review, we highlight the most relevant EWS preclinical and clinical studies in epigenetics, immunotherapy, and nanotherapy conducted in the last five years.
The presence of the chimeric EWSR1-FLI1 oncoprotein is the main and initiating event defining Ewing sarcoma (ES). The dysregulation of epigenomic and proteomic homeostasis induced by the oncoprotein ...contributes to a wide variety of events involved in oncogenesis and tumor progression. Attempts at studying the effects of EWSR1-FLI1 in non-tumor cells to understand the mechanisms underlying sarcomagenesis have been unsuccessful to date, as ectopic expression of EWSR1-FLI1 blocks cell cycle progression and induces apoptosis in the tested cell lines. Therefore, it is essential to find a permissive cell type for EWSR1-FLI1 expression that allows its endogenous molecular functions to be studied. Here we have demonstrated that HeLa cell lines are permissive to EWSR1-FLI1 ectopic expression, and that our model substantially recapitulates the endogenous activity of the EWSR1-FLI1 fusion protein. This model could contribute to better understanding ES sarcomagenesis by helping to understand the molecular mechanisms induced by the EWSR1-FLI1 oncoprotein.
Ewing sarcoma (EWS) is an aggressive bone and soft tissue tumor with high susceptibility to metastasize. The underlying molecular mechanisms leading to EWS metastases remain poorly understood. ...Epigenetic changes have been implicated in EWS tumor growth and progression. Linking epigenetics and metastases may provide insight into novel molecular targets in EWS and improve its treatment. Here, we evaluated the effects of a selective G9a histone methyltransferase inhibitor (BIX01294) on EWS metastatic process. Our results showed that overexpression of G9a in tumors from EWS patients correlates with poor prognosis. Moreover, we observe a significantly higher expression of G9a in metastatic EWS tumor as compared to either primary or recurrent tumor. Using functional assays, we demonstrate that pharmacological G9a inhibition using BIX01294 disrupts several metastatic steps in vitro, such as migration, invasion, adhesion, colony formation and vasculogenic mimicry. Moreover, BIX01294 reduces tumor growth and metastases in two spontaneous metastases mouse models. We further identified the sialidase NEU1 as a direct target and effector of G9a in the metastatic process in EWS. NEU1 overexpression impairs migration, invasion and clonogenic capacity of EWS cell lines. Overall, G9a inhibition impairs metastases in vitro and in vivo through the overexpression of NEU1. G9a has strong potential as a prognostic marker and may be a promising therapeutic target for EWS patients.
Ewing sarcoma (EWS) is an aggressive bone and soft tissue tumor of children and young adults in which the principal driver is a fusion gene, EWSR1-FLI1. Although the essential role of EWSR1-FLI1 ...protein in the regulation of oncogenesis, survival, and tumor progression processes has been described in-depth, little is known about the regulation of chimeric fusion-gene expression. Here, we demonstrate that the active nuclear HDAC6 in EWS modulates the acetylation status of specificity protein 1 (SP1), consequently regulating the SP1/P300 activator complex binding to EWSR1 and EWSR1-FLI1 promoters. Selective inhibition of HDAC6 impairs binding of the activator complex SP1/P300, thereby inducing EWSR1-FLI1 downregulation and significantly reducing its oncogenic functions. In addition, sensitivity of EWS cell lines to HDAC6 inhibition is higher than other tumor or non-tumor cell lines. High expression of HDAC6 in primary EWS tumor samples from patients correlates with a poor prognosis in two independent series accounting 279 patients. Notably, a combination treatment of a selective HDAC6 and doxorubicin (a DNA damage agent used as a standard therapy of EWS patients) dramatically inhibits tumor growth in two EWS murine xenograft models. These results could lead to suitable and promising therapeutic alternatives for patients with EWS.
Milk and egg allergies significantly impact the quality of life, particularly in children. In this regard, food oral immunotherapy (OIT) has emerged as an effective treatment option; however, the ...occurrence of frequent adverse reactions poses a challenge, necessitating close monitoring during treatment.
This study aims to evaluate the ability of a new mobile/web app called OITcontrol to monitor milk and egg OIT.
Patients undergoing milk or egg OIT were recruited and divided into 2 groups: the active group used the OITcontrol app in conjunction with standard written monitoring methods, whereas the control group relied solely on written diaries. Investigators documented hospital doses, hospital reactions, and administered treatments on the website. Patients recorded their daily allergen home-dose intake, home reactions, and administered treatments using the app. The following variables were compared between both groups: number and severity of hospital and reported home reactions, patient's adhesion to the OITcontrol app or written diary or both in terms of daily home-dose intake and home reactions recording, and treatment and dose adjustment compliance at home in case of reaction.
Sixteen patients were assigned to be monitored using the OITcontrol app along with additional written methods (active group), while 14 patients relied solely on a written paper diary (control group). A similar distribution was observed in terms of sex, age, basal characteristics, allergen treated in OIT, premedication, and sensitization profile. Active patients reported a comparable number of hospital and home reactions compared with the control group. In terms of recording system usage, 13/16 (81%) active patients used the OITcontrol app, while 10/14 (71%) control patients relied on the written diary. Among active patients, 6/16 (38%) used both methods, and 1 active patient used only written methods. However, control patients recorded home reactions more frequently than active patients (P=.009). Among active patients, the app was the preferred method for recording reactions (59/86, 69%), compared with the written diary (15/86, 17%) or both methods (12/86, 14%; P<.001). Treatment compliance in home-recorded reactions was similar between both groups (P=.15). However, treatment indications after an adverse reaction were more frequently followed (P=.04) in reactions recorded solely in the app (36/59, 61%) than in the written diary (29/71, 41%) or both systems (4/12, 33%). Moreover, compliance with dose adjustments after a moderate-severe reaction in home-recorded reactions was higher in the active group than in the control group (P<.001). Home reactions recorded only in the app (16/19, 84%) were more likely to follow dose adjustments (P<.001) than those recorded in the written diary (3/20, 15%) or using both methods (2/3, 67%).
The OITcontrol app appears to be a valuable tool for monitoring OIT treatment in children with food allergies. It proves to be a suitable method for recording daily home dose intakes and reactions, and it seems to enhance adherence to treatment indications following an adverse reaction as well as compliance with dose adjustments in home reactions. However, additional studies are necessary to comprehensively grasp the benefits and limitations of using the OITcontrol app in the management of OIT.
The global inhibition of transcription at the mitotic phase of the cell cycle occurs together with the general displacement of transcription factors from the mitotic chromatin. Nevertheless, the ...DNase- and potassium permanganate-hypersensitive sites are maintained on potentially active promoters during mitosis, helping to mark active genes at this stage of the cell cycle. Our study focuses on the role of histone acetylation and H3 (Lys-4) methylation in the maintenance of the competency of these active genes during mitosis. To this end we have analyzed histone modifications across the promoters and coding regions of constitutively active, inducible, and inactive genes in mitotic arrested cells. Our results show that basal histone modifications are maintained during mitosis at promoters and coding regions of the active and inducible RNA polymerase II-transcribed genes. In addition we have demonstrated that, together with H3 acetylation and H3 (Lys-4) methylation, H4 (Lys-12) acetylation at the coding regions contributes to the formation of a stable mark on active genes at this stage of the cell cycle. Finally, analysis of cyclin B1 gene activation during mitosis revealed that the former occurs with a strong increase of H3 (Lys-4) trimethylation but not H3 or H4 acetylation, suggesting that histone methyltransferases are active during this stage. These data demonstrate a critical role of histone acetylation and H3 (Lys-4) methylation during mitosis in marking and activating genes during the mitotic stage of the cell cycle.
Role for hACF1 in the G2/M damage checkpoint Sánchez-Molina, Sara; Mortusewicz, Oliver; Bieber, Béatrice ...
Nucleic acids research,
10/2011, Volume:
39, Issue:
19
Journal Article
Peer reviewed
Open access
Active chromatin remodelling is integral to the DNA damage response in eukaryotes, as damage sensors, signalling molecules and repair enzymes gain access to lesions. A variety of nucleosome ...remodelling complexes is known to promote different stages of DNA repair. The nucleosome sliding factors CHRAC/ACF of Drosophila are involved in chromatin organization during development. Involvement of corresponding hACF1-containing mammalian nucleosome sliding factors in replication, transcription and very recently also non-homologous end-joining of DNA breaks have been suggested. We now found that hACF1-containing factors are more generally involved in the DNA damage response. hACF1 depletion increases apoptosis, sensitivity to radiation and compromises the G2/M arrest that is activated in response to UV- and X-rays. In the absence of hACF1, γH2AX and CHK2ph signals are diminished. hACF1 and its ATPase partner SNF2H rapidly accumulate at sites of laser-induced DNA damage. hACF1 is also required for a tight checkpoint that is induced upon replication fork collapse. ACF1-depleted cells that are challenged with aphidicolin enter mitosis despite persistence of lesions and accumulate breaks in metaphase chromosomes. hACF1-containing remodellers emerge as global facilitators of the cellular response to a variety of different types of DNA damage.
Ewing sarcoma (EwS) is an aggressive tumor that affects adolescents and young adults. EwS is defined by a chromosomal translocation, EWSR1-FLI1 being the most common, that causes genome reprogramming ...through remodeling of enhancers. Here, we describe an unexpected function of RING1B, which is highly expressed in EwS. While retaining its repressive activity at Polycomb developmental regulated genes, RING1B colocalizes with EWSR1-FLI1 at active enhancers. We demonstrate that RING1B is necessary for the expression of key EWSR1-FLI1 targets by facilitating oncogene recruitment to their enhancers. Knockdown of RING1B impairs growth of tumor xenografts and expression of genes regulated by EWSR1-FLI1 bound enhancers. Pharmacological inhibition of AURKB with AZD1152 increases H2Aub levels causing down-regulation of RING1B/EWSR1-FLI1 common targets. Our findings demonstrate that RING1B is a critical modulator of EWSR1-FLI1-induced chromatin remodeling, and its inhibition is a potential therapeutic strategy for the treatment of these tumors.
Ewing sarcoma (EwS) is a human malignant tumor typically driven by the Ewing sarcoma-Friend leukemia integration (EWS-FLI) fusion protein. A paucity of genetically modified animal models, partially ...owed to the high toxicity of EWS-FLI, hinders research on EwS. Here, we report a spontaneous mutant variant, EWS-FLI
, that circumvents the toxicity issue in Drosophila. Through proteomic and genomic analyses, we show that human EWS-FLI
interacts with the Drosophila homologues of EWS-FLI human protein partners, including core subunits of chromatin remodeling complexes, the transcription machinery, and the spliceosome; brings about a massive dysregulation of transcription that affects a significant fraction of known targets of EWS-FLI in human cells; and modulates splicing. We also show that EWS-FLI
performs in Drosophila the two major neomorphic activities that it is known to have in human cells: activation of transcription from GGAA microsatellites and out competition of ETS transcription factors. We conclude that EWS-FLI
reproduces in Drosophila the known oncogenic activities of EWS-FLI that drive EwS tumorigenesis in humans. These results open up an unprecedented opportunity to investigate EWS-FLI's oncogenic pathways in vivo in a genetically tractable organism.
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