Modulation of Mcl-1 sensitizes glioblastoma to TRAIL-induced apoptosis.
Glioblastoma (GBM) is the most aggressive form of primary brain tumour, with dismal patient outcome. Treatment failure is associated with intrinsic or acquired apoptosis resistance and the presence of a highly tumourigenic subpopulation of cancer cells called GBM stem cells. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has emerged as a promising novel therapy for some treatment-resistant tumours but unfortunately GBM can be completely resistant to TRAIL monotherapy. In this study, we identified Mcl-1, an anti-apoptotic Bcl-2 family member, as a critical player involved in determining the sensitivity of GBM to TRAIL-induced apoptosis. Effective targeting of Mcl-1 in TRAIL resistant GBM cells, either by gene silencing technology or by treatment with R-roscovitine, a cyclin-dependent kinase inhibitor that targets Mcl-1, was demonstrated to augment sensitivity to TRAIL, both within GBM cells grown as monolayers and in a 3D tumour model. Finally, we highlight that two separate pathways are activated during the apoptotic death of GBM cells treated with a combination of TRAIL and R-roscovitine, one which leads to caspase-8 and caspase-3 activation and a second pathway, involving a Mcl-1:Noxa axis. In conclusion, our study demonstrates that R-roscovitine in combination with TRAIL presents a promising novel strategy to trigger cell death pathways in glioblastoma.
Health Research Board (RP/2008/69 and HRA_POR/ 2012/88) and the RCSI Research Committee (GR 08-0155) to BMM. BMM is a Science Foundation Ireland Stokes Lecturer (07/SK/B1243a). Deutsche Krebshilfe (grant 108795) to DK. SK was supported by a Science Foundation Ireland Short Term Travel Fellowship (08/IN.1/B1949-STTF 11).
CommentsThis article is also available at http://link.springer.com/article/10.1007/s10495-013-0935-2
Published CitationMurphy AC, Weyhenmeyer B, Noonan J, Kilbride SM, Schimansky S, Loh KP, Kogel D, Letai AG, Prehn JHM, Murphy B. Modulation of Mcl-1 sensitizes glioblastoma to TRAIL-induced apoptosis. Apoptosis. 2014;19(4);629-642.
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