Glioblastoma (GBM) is the most aggressive primary brain tumor in adults. Despite progress in surgical and medical neuro-oncology, prognosis for GBM patients remains dismal. It has been demonstrated that the modest benefit of conventional therapies is due to the presence of glioblastoma stem cells (GSCs) that cause tumor relapse and chemoresistance. Thus, the identification of specific ligands for GSCs could be fundamental for GBM improvement in survival.
Here, using a cell-SELEX approach on human primary GSCs, we generated RNA aptamers –namely, a 40L sequence and A40s, a truncated form– that bind GSCs.
The aptamers were selective for human GSCs, they were able to inhibit stemness, cell growth and migration, and strongly reduced tumor proliferation in vivo. Moreover, 40L and A40s were rapidly internalized upon target binding and, therefore, may serve as selective vehicles for therapeutics. Furthermore, A40s is able to cross the blood brain barrier (BBB). Using several approaches, we have identified the aptamer target in the Ephrin type-A receptor 2 (EphA2) which is overexpressed in GSCs compared to differentiated cells.
Given the role of GSCs in GBM recurrence and therapy resistance, 40L and A40s represent innovative therapeutic and diagnostic tool for GBM.
Gerolama Condorelli.
Federico II, Naples.
All authors have declared no conflicts of interest.