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oai:uvadoc.uva.es:10324/216772021-06-23T10:09:48Zcom_10324_1151com_10324_931com_10324_894col_10324_1278

The PARP inhibitor olaparib enhances the sensitivity of Ewing sarcoma to trabectedin Ordóñez García, José Luis Amaral, Ana Teresa Montero Carcaboso, Ángel Herrero Martín, David García Macías, María del Carmen Alonso López, Diego Pascual Pastor, Guillem San Segundo, Laura Vila Ubach, Mónica Rodrigues, Telmo Fraile, Susana Teodosio, Cristina Mayo Iscar, Agustín Aracil, Miguel Galmarini, Carlos María Martínez Tirado, Oscar Mora Graupera, Jaume Álava, Enrique de Sarcoma Producción Científica 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. 2016-12-13T19:14:51Z 2016-12-13T19:14:51Z 2015 info:eu-repo/semantics/article Oncotarget, 2015, 6 (22), p. 18875-90 1949-2553 http://uvadoc.uva.es/handle/10324/21677 10.18632/oncotarget.4303 Oncotarget eng http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Attribution-NonCommercial-NoDerivatives 4.0 International Impact Journals SI