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Telomerase inhibition abolishes the tumorigenicity of pediatric ependymoma tumor-initiating cells

dc.contributor.authorBarszczyk, Mark
dc.contributor.authorBuczkowicz, Pawel
dc.contributor.authorCastelo-Branco, Pedro
dc.contributor.authorMack, Stephen C.
dc.contributor.authorRamaswamy, Vijay
dc.contributor.authorMangerel, Joshua
dc.contributor.authorAgnihotri, Sameer
dc.contributor.authorRemke, Marc
dc.contributor.authorGolbourn, Brian
dc.contributor.authorPajovic, Sanja
dc.contributor.authorElizabeth, Cynthia
dc.contributor.authorYu, Man
dc.contributor.authorLuu, Betty
dc.contributor.authorMorrison, Andrew
dc.contributor.authorAdamski, Jennifer
dc.contributor.authorNethery-Brokx, Kathleen
dc.contributor.authorLi, Xiao-Nan
dc.contributor.authorVan Meter, Timothy
dc.contributor.authorDirks, Peter B.
dc.contributor.authorRutka, James T.
dc.contributor.authorTaylor, Michael D.
dc.contributor.authorTabori, Uri
dc.contributor.authorHawkins, Cynthia
dc.date.accessioned2018-12-07T14:52:48Z
dc.date.available2018-12-07T14:52:48Z
dc.date.issued2014-12
dc.description.abstractPediatric ependymomas are highly recurrent tumors resistant to conventional chemotherapy. Telomerase, a ribonucleoprotein critical in permitting limitless replication, has been found to be critically important for the maintenance of tumor-initiating cells (TICs). These TICs are chemoresistant, repopulate the tumor from which they are identified, and are drivers of recurrence in numerous cancers. In this study, telomerase enzymatic activity was directly measured and inhibited to assess the therapeutic potential of targeting telomerase. Telomerase repeat amplification protocol (TRAP) (n = 36) and C-circle assay/telomere FISH/ATRX staining (n = 76) were performed on primary ependymomas to determine the prevalence and prognostic potential of telomerase activity or alternative lengthening of telomeres (ALT) as telomere maintenance mechanisms, respectively. Imetelstat, a phase 2 telomerase inhibitor, was used to elucidate the effect of telomerase inhibition on proliferation and tumorigenicity in established cell lines (BXD-1425EPN, R254), a primary TIC line (E520) and xenograft models of pediatric ependymoma. Over 60 % of pediatric ependymomas were found to rely on telomerase activity to maintain telomeres, while no ependymomas showed evidence of ALT. Children with telomerase-active tumors had reduced 5-year progression-free survival (29 +/- A 11 vs 64 +/- A 18 %; p = 0.03) and overall survival (58 +/- A 12 vs 83 +/- A 15 %; p = 0.05) rates compared to those with tumors lacking telomerase activity. Imetelstat inhibited proliferation and self-renewal by shortening telomeres and inducing senescence in vitro. In vivo, Imetelstat significantly reduced subcutaneous xenograft growth by 40 % (p = 0.03) and completely abolished the tumorigenicity of pediatric ependymoma TICs in an orthotopic xenograft model. Telomerase inhibition represents a promising therapeutic approach for telomerase-active pediatric ependymomas found to characterize high-risk ependymomas.
dc.description.sponsorshipCanadian Institutes of Health Research [MOP 82727]
dc.description.versioninfo:eu-repo/semantics/publishedVersion
dc.identifier.doi10.1007/s00401-014-1327-6
dc.identifier.issn0001-6322
dc.identifier.issn1432-0533
dc.identifier.urihttp://hdl.handle.net/10400.1/11219
dc.language.isoeng
dc.peerreviewedyes
dc.publisherSpringer
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectTert promoter mutations
dc.subjectIntracranial ependymoma
dc.subjectMultifactorial analysis
dc.subjectTherapeutic target
dc.subjectHighly recurrent
dc.subjectGrowth arrest
dc.subjectBrain-tumors
dc.subjectStem-cells
dc.subjectChildhood
dc.subjectExpression
dc.titleTelomerase inhibition abolishes the tumorigenicity of pediatric ependymoma tumor-initiating cells
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage877
oaire.citation.issue6
oaire.citation.startPage863
oaire.citation.titleActa Neuropathologica
oaire.citation.volume128
person.familyNameCastelo-Branco
person.givenNamePedro
person.identifier.ciencia-idE015-7F8F-5CA1
person.identifier.orcid0000-0002-3453-3978
rcaap.rightsopenAccess
rcaap.typearticle
relation.isAuthorOfPublicationbb25b5ad-1769-42be-a7d3-8fe76215aa23
relation.isAuthorOfPublication.latestForDiscoverybb25b5ad-1769-42be-a7d3-8fe76215aa23

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