Identification of DNA aptamers to human glioblastoma stem-like cells

• Grant number: 14/00462-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: September 01, 2014
• End date: August 31, 2018
• Field of knowledge: Biological Sciences - Biochemistry
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Alexander Henning Ulrich
• Grantee: Erika de Simone Molina
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 12/50880-4 - Stem cells: from basic studies of kinin and purinergic receptor roles towards therapeutical applications, AP.TEM
• Associated scholarship(s): 16/03686-9 - Identification of a drug-delivery aptamer against human glioblastoma stem-like cells, BE.EP.DR

Abstract

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor in adults, with one of the worst survival rates among all human cancers. Increasing evidences indicate that the poor prognosis of GBM is linked to an intratumoral population of glioblastoma stem cells (GSC), which would be resistant to radiation and chemotherapy and are postulated to further recapitulate the GBM tumorigenesis. In this perspective the aim of this project is to identify a molecular signature in GSC based on the selection of a specific aptamer for a GBM cell line enriched in GSC, shared nor by a GBM cell line without enriched GSC (non-GSC) neither by neural progenitor cells (NPC). In a first step the enrichment of GSC in the GBM cell line will be evaluated by confirming their stemness phenotype based on their ability of in vitro colony formation, resistance to chemotherapy treatment and the expression of GSC markers. In the next step aptamers will be identified using the cell-SELEX technique with positive selection against the enriched GSC and negative selection against the non-GSC and the NPC. In the next step the aptamer to be identified will be chemically modified and used to image and to purify the GSC from human GBM primary cultures by image cytometry and fluorescence assisted cell sorting, respectively. Finally the purified GSC will be compared to the remaining GBM cells and to the total number of cells derived from the GBM primary cultures as regards to the GSC stemness phenotype, using the in vivo tumorigenesis assay. The demonstration of a GSC phenotype of aptamer-purified GSC from GBM primary cultures will indicate a specific molecular signature of the GSC, which will contribute to better elucidate the GSC biology and provide relevant information for GBM diagnosis/prognosis and drug delivery. (AU)