Fiche publication
Date publication
octobre 2015
Auteurs
Membres identifiés du Cancéropôle Est :
Dr CHOULIER Laurence
,
Dr DONTENWILL Monique
,
Dr ETIENNE-SELLOUM Nelly
,
Dr GUERIN Eric
,
Pr LEHMANN Maxime
,
Dr MARTIN Sophie
,
Dr NUESCH Jürg
Tous les auteurs :
Renner G, Janouskova H, Noulet F, Koenig V, Guerin E, Bar S, Nuesch J, Rechenmacher F, Neubauer S, Kessler H, Blandin AF, Choulier L, Etienne-Selloum N, Lehmann M, Lelong-Rebel I, Martin S, Dontenwill M
Lien Pubmed
Résumé
Integrin alpha5beta1 expression is correlated with a worse prognosis in high-grade glioma. We previously unraveled a negative crosstalk between integrin alpha5beta1 and p53 pathway, which was proposed to be part of the resistance of glioblastoma to chemotherapies. The restoration of p53 tumor-suppressor function is under intensive investigations for cancer therapy. However, p53-dependent apoptosis is not always achieved by p53-reactivating compounds such as Nutlin-3a, although full transcriptional activity of p53 could be obtained. Here we investigated whether integrin alpha5beta1 functional inhibition or repression could sensitize glioma cells to Nutlin-3a-induced p53-dependent apoptosis. We discovered that alpha5beta1 integrin-specific blocking antibodies or small RGD-like antagonists in association with Nutlin-3a triggered a caspase (Casp) 8/Casp 3-dependent strong apoptosis in glioma cells expressing a functional p53. We deciphered the molecular mechanisms involved and we showed the crucial role of two anti-apoptotic proteins, phosphoprotein enriched in astrocytes 15 (PEA-15) and survivin in glioma cell apoptotic outcome. PEA-15 is under alpha5beta1 integrin/AKT (protein kinase B) control and survivin is a p53-repressed target. Moreover, interconnections between integrin and p53 pathways were revealed. Indeed PEA-15 repression by specific small-interfering RNA (siRNA)-activated p53 pathway to repress survivin and conversely survivin repression by specific siRNA decreased alpha5beta1 integrin expression. This pro-apoptotic loop could be generalized to several glioma cell lines, whatever their p53 status, inasmuch PEA-15 and survivin protein levels were decreased. Our findings identify a novel mechanism whereby inhibition of alpha5beta1 integrin and activation of p53 modulates two anti-apoptotic proteins crucially involved in the apoptotic answer of glioma cells. Importantly, our results suggest that high-grade glioma expressing high level of alpha5beta1 integrin may benefit from associated therapies including integrin antagonists and repressors of survivin expression.Cell Death and Differentiation advance online publication, 16 October 2015; doi:10.1038/cdd.2015.131.
Référence
Cell Death Differ. 2015 Oct 16
