Publications by authors named "Ana Teresa Amaral"

11 Publications

  • Page 1 of 1

Endoglin in the Spotlight to Treat Cancer.

Int J Mol Sci 2021 Mar 20;22(6). Epub 2021 Mar 20.

Molecular Pathology of Sarcomas, Institute of Biomedicine of Sevilla (IBiS), Virgen del Rocio University Hospital, CSIC, University of Sevilla, CIBERONC, 41013 Seville, Spain.

A spotlight has been shone on endoglin in recent years due to that fact of its potential to serve as both a reliable disease biomarker and a therapeutic target. Indeed, endoglin has now been assigned many roles in both physiological and pathological processes. From a molecular point of view, endoglin mainly acts as a co-receptor in the canonical TGFβ pathway, but also it may be shed and released from the membrane, giving rise to the soluble form, which also plays important roles in cell signaling. In cancer, in particular, endoglin may contribute to either an oncogenic or a non-oncogenic phenotype depending on the cell context. The fact that endoglin is expressed by neoplastic and non-neoplastic cells within the tumor microenvironment suggests new possibilities for targeted therapies. Here, we aimed to review and discuss the many roles played by endoglin in different tumor types, as well as the strong evidence provided by pre-clinical and clinical studies that supports the therapeutic targeting of endoglin as a novel clinical strategy.
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http://dx.doi.org/10.3390/ijms22063186DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003971PMC
March 2021

Breakthrough Technologies Reshape the Ewing Sarcoma Molecular Landscape.

Cells 2020 03 26;9(4). Epub 2020 Mar 26.

Institute of Biomedicine of Sevilla (IBiS), Virgen del Rocio University Hospital/CSIC/University of Sevilla/CIBERONC, 41013 Seville, Spain.

Ewing sarcoma is a highly aggressive round cell mesenchymal neoplasm, most often occurring in children and young adults. At the molecular level, it is characterized by the presence of recurrent chromosomal translocations. In the last years, next-generation technologies have contributed to a more accurate diagnosis and a refined classification. Moreover, the application of these novel technologies has highlighted the relevance of intertumoral and intratumoral molecular heterogeneity and secondary genetic alterations. Furthermore, they have shown evidence that genomic features can change as the tumor disseminates and are influenced by treatment as well. Similarly, next-generation technologies applied to liquid biopsies will significantly impact patient management by allowing the early detection of relapse and monitoring response to treatment. Finally, the use of these novel technologies has provided data of great value in order to discover new druggable pathways. Thus, this review provides concise updates on the latest progress of these breakthrough technologies, underscoring their importance in the generation of key knowledge, prognosis, and potential treatment of Ewing Sarcoma.
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http://dx.doi.org/10.3390/cells9040804DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7226764PMC
March 2020

Preclinical Efficacy of Endoglin-Targeting Antibody-Drug Conjugates for the Treatment of Ewing Sarcoma.

Clin Cancer Res 2019 04 12;25(7):2228-2240. Epub 2018 Nov 12.

Institute of Biomedicine of Sevilla (IBiS), Virgen del Rocio University Hospital/CSIC/University of Sevilla/CIBERONC, Seville, Spain.

Purpose: Endoglin (ENG; CD105) is a coreceptor of the TGFβ family that is highly expressed in proliferating endothelial cells. Often coopted by cancer cells, ENG can lead to neo-angiogenesis and vasculogenic mimicry in aggressive malignancies. It exists both as a transmembrane cell surface protein, where it primarily interacts with TGFβ, and as a soluble matricellular protein (sENG) when cleaved by matrix metalloproteinase 14 (MMP14). High ENG expression has been associated with poor prognosis in Ewing sarcoma, an aggressive bone cancer that primarily occurs in adolescents and young adults. However, the therapeutic value of ENG targeting has not been fully explored in this disease.

Experimental Design: We characterized the expression pattern of transmembrane ENG, sENG, and MMP14 in preclinical and clinical samples. Subsequently, the antineoplastic potential of two novel ENG-targeting monoclonal antibody-drug conjugates (ADC), OMTX503 and OMTX703, which differed only by their drug payload (nigrin-b A chain and cytolysin, respectively), was assessed in cell lines and preclinical animal models of Ewing sarcoma.

Results: Both ADCs suppressed cell proliferation in proportion to the endogenous levels of ENG observed . Moreover, the ADCs significantly delayed tumor growth in Ewing sarcoma cell line-derived xenografts and patient-derived xenografts in a dose-dependent manner.

Conclusions: Taken together, these studies demonstrate potent preclinical activity of first-in-class anti-ENG ADCs as a nascent strategy to eradicate Ewing sarcoma.
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http://dx.doi.org/10.1158/1078-0432.CCR-18-0936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6445738PMC
April 2019

Ex vivo identification and characterization of a population of CD13(high) CD105(+) CD45(-) mesenchymal stem cells in human bone marrow.

Stem Cell Res Ther 2015 Sep 7;6:169. Epub 2015 Sep 7.

Department of Medicine and Cytometry Service (NUCLEUS), Cancer Research Center (IBMCC, USAL-CSIC), Institute for Biomedical Research of Salamanca (IBSAL), University of Salamanca (USAL), Salamanca, Spain.

Introduction: Mesenchymal stem cells (MSCs) are multipotent cells capable of self-renewal and multilineage differentiation. Their multipotential capacity and immunomodulatory properties have led to an increasing interest in their biological properties and therapeutic applications. Currently, the definition of MSCs relies on a combination of phenotypic, morphological and functional characteristics which are typically evaluated upon in vitro expansion, a process that may ultimately lead to modulation of the immunophenotypic, functional and/or genetic features of these cells. Therefore, at present there is great interest in providing markers and phenotypes for direct in vivo and ex vivo identification and isolation of MSCs.

Methods: Multiparameter flow cytometry immunophenotypic studies were performed on 65 bone marrow (BM) samples for characterization of CD13(high) CD105(+) CD45(-) cells. Isolation and expansion of these cells was performed in a subset of samples in parallel to the expansion of MSCs from mononuclear cells following currently established procedures. The protein expression profile of these cells was further assessed on (paired) primary and in vitro expanded BM MSCs, and their adipogenic, chondrogenic and osteogenic differentiation potential was also determined.

Results: Our results show that the CD13(high) CD105(+) CD45(-) immunophenotype defines a minor subset of cells that are systematically present ex vivo in normal/reactive BM (n = 65) and that display immunophenotypic features, plastic adherence ability, and osteogenic, adipogenic and chondrogenic differentiation capacities fully compatible with those of MSCs. In addition, we also show that in vitro expansion of these cells modulates their immunophenotypic characteristics, including changes in the expression of markers currently used for the definition of MSCs, such as CD105, CD146 and HLA-DR.

Conclusions: BM MSCs can be identified ex vivo in normal/reactive BM, based on a robust CD13(high) CD105(+) and CD45(-) immunophenotypic profile. Furthermore, in vitro expansion of these cells is associated with significant changes in the immunophenotypic profile of MSCs.
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http://dx.doi.org/10.1186/s13287-015-0152-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562124PMC
September 2015

The PARP inhibitor olaparib enhances the sensitivity of Ewing sarcoma to trabectedin.

Oncotarget 2015 08;6(22):18875-90

Laboratory of Molecular Pathology, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, Seville, Spain.

Recent preclinical evidence has suggested that Ewing Sarcoma (ES) bearing EWSR1-ETS fusions could be particularly sensitive to PARP inhibitors (PARPinh) in combination with DNA damage repair (DDR) agents. Trabectedin is an antitumoral agent that modulates EWSR1-FLI1 transcriptional functions, causing DNA damage. Interestingly, PARP1 is also a transcriptional regulator of EWSR1-FLI1, and PARPinh disrupts the DDR machinery. Thus, given the impact and apparent specificity of both agents with regard to the DNA damage/DDR system and EWSR1-FLI1 activity in ES, we decided to explore the activity of combining PARPinh and Trabectedin in in vitro and in vivo experiments. The combination of Olaparib and Trabectedin was found to be highly synergistic, inhibiting cell proliferation, inducing apoptosis, and the accumulation of G2/M. The drug combination also enhanced γH2AX intranuclear accumulation as a result of DNA damage induction, DNA fragmentation and global DDR deregulation, while EWSR1-FLI1 target expression remained unaffected. The effect of the drug combination was corroborated in a mouse xenograft model of ES and, more importantly, in two ES patient-derived xenograft (PDX) models in which the tumors showed complete regression. In conclusion, the combination of the two agents leads to a biologically significant deregulation of the DDR machinery that elicits relevant antitumor activity in preclinical models and might represent a promising therapeutic tool that should be further explored for translation to the clinical setting.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4662461PMC
http://dx.doi.org/10.18632/oncotarget.4303DOI Listing
August 2015

Trabectedin efficacy in Ewing sarcoma is greatly increased by combination with anti-IGF signaling agents.

Clin Cancer Res 2015 Mar 21;21(6):1373-82. Epub 2015 Jan 21.

Experimental Oncology Lab, CRS Development of Biomolecular Therapies, Rizzoli Institute, Bologna, Italy.

Purpose: Goal of this study was to identify mechanisms that limit efficacy of trabectedin (ET-743, Yondelis) in Ewing sarcoma (EWS), so as to develop a clinical applicable combination therapy.

Experimental Design: By chromatin immunoprecipitation, we analyzed EWS-FLI1 binding to the promoters of several target genes, such as TGFβR2, CD99, insulin-like growth factor receptor 1 (IGF1R), and IGF1, both in vitro and in xenografts treated with trabectedin or doxorubicin. Combined therapy with trabectedin and anti-IGF1R agents (AVE1642 HAb; OSI-906) was tested in vitro and in xenografts.

Results: We confirm that both trabectedin and doxorubicin were able to strongly reduce EWS-FLI1 (both type I and type II) binding to two representative target genes (TGFβR2 and CD99), both in vitro and in xenografts. However, trabectedin, but not doxorubicin, was also able to increase the occupancy of EWS-FLI1 to IGF1R promoters, leading to IGF1R upregulation. Inhibition of IGF1R either by the specific AVE1642 human antibody or by the dual IGF1R/insulin receptor inhibitor OSI-906 (Linsitinib) greatly potentiate the efficacy of trabectedin in the 13 EWS cell lines here considered as well as in TC-71 and 6647 xenografts. Combined therapy induced synergistic cytotoxic effects. Trabectedin and OSI-906 deliver complementary messages that likely converge on DNA-damage response and repair pathways.

Conclusions: We showed that trabectedin may not only inhibit but also enhance the binding of EWS-FLI1 to certain target genes, leading to upregulation of IGF1R. We here provide the rationale for combining trabectedin to anti-IGF1R inhibitors.
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http://dx.doi.org/10.1158/1078-0432.CCR-14-1688DOI Listing
March 2015

Characterization of human mesenchymal stem cells from ewing sarcoma patients. Pathogenetic implications.

PLoS One 2014 3;9(2):e85814. Epub 2014 Feb 3.

Molecular Pathology Program, Institute of Biomedical Research of Salamanca-Centro de Investigación del Cáncer, Centro de Investigación del Cáncer (IBSAL-CIC), Salamanca, Spain ; Instituto de Biomedicina de Sevilla (IBiS), CSIC-Universidad de Sevilla, Department of Pathology and Biobank, Hospital Universitario Virgen del Rocío, Seville, Spain.

Background: Ewing Sarcoma (EWS) is a mesenchymal-derived tumor that generally arises in bone and soft tissue. Intensive research regarding the pathogenesis of EWS has been insufficient to pinpoint the early events of Ewing sarcomagenesis. However, the Mesenchymal Stem Cell (MSC) is currently accepted as the most probable cell of origin.

Materials And Methods: In an initial study regarding a deep characterization of MSC obtained specifically from EWS patients (MSC-P), we compared them with MSC derived from healthy donors (MSC-HD) and EWS cell lines. We evaluated the presence of the EWS-FLI1 gene fusion and EWSR1 gene rearrangements in MSC-P. The presence of the EWS transcript was confirmed by q-RT-PCR. In order to determine early events possibly involved in malignant transformation, we used a multiparameter quantitative strategy that included both MSC immunophenotypic negative/positive markers, and EWS intrinsic phenotypical features. Markers CD105, CD90, CD34 and CD45 were confirmed in EWS samples.

Results: We determined that MSC-P lack the most prevalent gene fusion, EWSR1-FLI1 as well as EWSR1 gene rearrangements. Our study also revealed that MSC-P are more alike to MSC-HD than to EWS cells. Nonetheless, we also observed that EWS cells had a few overlapping features with MSC. As a relevant example, also MSC showed CD99 expression, hallmark of EWS diagnosis. However, we observed that, in contrast to EWS cells, MSC were not sensitive to the inhibition of CD99.

Conclusions: In conclusion, our results suggest that MSC from EWS patients behave like MSC-HD and are phenotypically different from EWS cells, thus raising important questions regarding MSC role in sarcomagenesis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0085814PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3911896PMC
December 2014

Innovative therapies in Ewing Sarcoma.

Adv Anat Pathol 2014 Jan;21(1):44-62

*Molecular Pathology Program, Institute of Biomedical Research of Salamanca-Centro de Investigación del Cáncer, Centro de Investigación del Cancér (IBSAL-CIC), Campus Miguel de Unamuno S/N, Salamanca †Pathology Department, Hospital Universitario Virgen del Rocio-IBiS, Sevilla, Spain.

Ewing Sarcoma is a developmental tumor characterized by balanced chromosomal translocations and formation of new fusion genes, which are the main hallmark of this rare entity. Despite the vast knowledge regarding the molecular aspects of this rare malignancy obtained in the last few years, including the discovery of new therapeutic targets, many questions still remain open. In this review we focus on the research on targeted therapies in this malignancy, and discussed some bottlenecks related to this such as the possible role of pathologists, the availability of samples, the lack of appropriate animal models, and the resources needed to carry out preclinical and clinical research.
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http://dx.doi.org/10.1097/PAP.0000000000000003DOI Listing
January 2014

IGF1R signaling in Ewing sarcoma is shaped by clathrin-/caveolin-dependent endocytosis.

PLoS One 2011 17;6(5):e19846. Epub 2011 May 17.

Laboratory 20-Molecular Pathology of Sarcomas Laboratory, Centro de Investigación del Cáncer-IBMCC, Universidad de Salamanca-CSIC, Salamanca, Spain.

Receptor endocytosis is critical for cell signaling. IGF1R mediates an autocrine loop that is de-regulated in Ewing Sarcoma (ES) cells. Here we study the impact of IGF1R internalization, mediated by clathrin and caveolin-1 (CAV1), in ES signaling. We used clathrin and CAV1-siRNA to interfere in clathrin- and caveolin-dependent endocytosis. Chlorpromazine (CPMZ) and methyl-beta-cyclo-dextrin (MCD) were also used in order to inhibit clathrin- and caveolin-dependent endocytosis, respectively. We analyzed IGF1R internalization and co-localization with clathrin and CAV1 upon ligand binding, as well as the status of the IGF1R pathway, cellular proliferation, and the apoptosis of interfered and inhibited ES cells. We performed a high-throughput tyrosine kinase phosphorylation assay to analyze the effects of combining the IGF1R tyrosine kinase inhibitor AEW541 (AEW) with CPMZ or MCD on the intracellular phospho-proteome. We observed that IGF1R is internalized upon ligand binding in ES cells and that this process is dependent on clathrin or CAV1. The blockage of receptor internalization inhibited AKT and MAPK phosphorylation, reducing the proliferative rate of ES cells and increasing the levels of apoptosis. Combination of AEW with CPMZ or MCD largely enhanced these effects. CAV1 and clathrin endocytosis controls IGF1R internalization and signaling and has a profound impact on ES IGF1R-promoted survival signaling. We propose the combination of tyrosine-kinase inhibitors with endocytosis inhibitors as a new therapeutic approach to achieve a stronger degree of receptor inhibition in this, or other neoplasms dependent on IGF1R signaling.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0019846PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096649PMC
September 2011

The clinical relevance of molecular genetics in soft tissue sarcomas.

Adv Anat Pathol 2010 May;17(3):162-81

Centro de Investigación del Cáncer-IBMCC, Universidad de Salamanca-CSIC, Spain.

Bone and soft tissue sarcomas are an infrequent and heterogeneous group of mesenchymal tumors including more than a hundred different entities attending to histologic patterns. Research into the molecular aspects of sarcomas has increased greatly in the last few years. This enormous amount of knowledge has allowed, for instance, to refine the classification of sarcomas, improve the diagnosis, and increase the number of therapeutical targets available, most of them under preclinical evaluation. However, other important key issues, such as sarcomagenesis and the cell of origin of sarcomas, remain unresolved. From a molecular point of view, these neoplasias are grouped into 2 main types: (a) sarcomas showing relatively simple karyotypes and translocations, which originate gene fusions (eg, EWS-FLI1 in Ewing sarcoma) or point mutations (eg, c-kit in the gastrointestinal tumors) and (b) sarcomas showing unspecific gene alterations, very complex karyotypes, and no translocations. The discovery of the early mechanisms involved in the genesis of sarcomas, the more relevant signaling pathways, and the development of genetically engineered mouse models could also provide a new individualized therapeutic strategy against these tumors. This review describes the clinical application of some of the molecular alterations found in sarcomas, some advances in the field of sarcomagenesis, and the development of animal models.
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http://dx.doi.org/10.1097/PAP.0b013e3181d98cbfDOI Listing
May 2010