Abstract 169: Identification of RNA aptamers selectively recognizing and affecting glioblastoma stem cells

Glioblastoma (GBM) is the most frequent and aggressive primary brain tumour in adults. Despite advances in surgical and medical neuro oncology, prognosis for GBM patients remains dismal, with a median survival of about 15 months. It has been demonstrated that the modest benefit of conventional therapies depends on a small population of cancer stem cells within the tumor, named Glioma Stem Cells (GSCs) that cause tumor relapse and chemoresistance and therefore could play a key role in GBM recurrence. Thus, the identification of new specific ligands for GSCs could be a fundamental challenge for the development of effective glioma therapies. Here, we developed an in vitro evolution based approach, named differential whole cellSELEX; it is used to generate nucleic acid ligands, named aptamers, with high affinity and specificity for GSCs. Aptamers, were obtained through the iterative evolution of a random pool of sequences using human primary GSCs as target. Among different potential candidates we focused on one sequence, named 40L. The 40L aptamer and its truncated form, 40S, were selective for human GSCs distinguishing them from tumor differentiated cells, obtained from the stem cells induced to differentiate. 40L revealed to be functionally active on target cells and able to inhibit stemness, cell growth and migration. 40s preserves binding ability of 40L sequence and it has further proven to strongly reduce tumor proliferation in in vivo experiment. Moreover, both 40L and 40s were able to rapidly internalize upon target binding and therefore may serve as selective vehicle for therapeutics.In conclusion, our results indicate that 40L and its short form 40s can selectively target GSCs both in vitro and in vivo. Given the crucial role of these cells in GBM recurrence and therapy resistance, 40L and 40s represent innovative drug candidates with a great potential in the GBM treatment. Citation Format: Alessandra Affinito, Cristina Quintavalle, Maurizio Albero, Claudia Vilardo, Francesco Palma, Giuseppina Roscigno, Lucia Ricci Vitiani, Roberto Pallini, Carla Lucia Esposito, Vittorio de Franciscis, Gerolama Condorelli. Identification of RNA aptamers selectively recognizing and affecting glioblastoma stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 169.