ET-01 * IL-13 CONJUGATED QUANTUM DOTS FOR THE IDENTIFICATION AND CHARACTERIZATION OF GLIOMA STEM CELLS, SOLUBLE RECEPTORS AND EXOSOMES RELEASED BY GBM TUMORS

Abstract

Glioblastoma Multiforme is an aggressive brain tumor combining high infiltrative properties with a heterogenous nature making it challenging to identify and remove them by surgery and increasing their resistance to other conventional therapies. GBM tumors are known to express the IL-13Rα2 receptors which we have used to target nanoliposomes for enhancing theranostic efficacy. In our present investigation we utilized interleukin-13 ( IL-13) conjugated quantum dots (IL-13QD) to selectively bind the glioma stem cells in culture and the soluble receptor in a medium and the exosomes released in a biological fluid. The binding phenomenon was characterized by various techniques like atomic force microscopy, dynamic light scattering method, electron microscopy and fluorescent microscopy. Investigation was also performed to determine the release of soluble IL-13Rα2 receptor and IL-13Rα2 expressing exosomes from the glioma stem cells in the culture media and in the cerebrospinal fluid. After confirming the presence of soluble receptor by immunoblots and ELISA and exosomes by electron microscopy and dynamic light scattering method, in vitro studies were performed with the IL-13QD in a media containing the exosomes and soluble receptors to investigate the binding and aggregation properties of the IL-13QD. Our investigation revealed the aggregation properties of the IL-13QD in the presence of soluble receptor and exosomes indicating a correlation between the receptor expression and aggregation and dissociation of quantum dots. Further studies are in progress with patient samples that would lead to a development of a biomarker and a therapeutic agent for the highly malignant brain tumors.