DIPG-35. A SIRNA APPROACH FOR TARGETING IMMUNOSUPPRESSIVE IDO1 IN PEDIATRIC DIFFUSE INTRINSIC PONTINE GLIOMA

Abstract

OBJECTIVE/GOALS: The purpose of our project is to delineate the role of indoleamine 2,3 dioxygenase 1 (IDO1) in pediatric diffuse intrinsic pontine glioma (DIPG), and develop therapeutic potential of IDO1 inhibition through small inhibitory (si)RNA oligonucleotides and spherical nucleic acids (SNAs). Our specific aims are: (1) confirm the gene expression, protein levels and enzymatic activity of IDO1 in different human DIPG cell lines; (2) generate and characterize siRNA oligonucleotides specifically targeting human IDO1 for an in vitro targeted approach to validate knockdown of IDO1 expression; and (3) generate and characterize gold nanoparticles for further targeted approach to inhibit IDO1. METHODS/STUDY: Unique patient-derived DIPG cell lines were grown in culture, stimulated with increasing concentrations of IFN-γ, and analyzed by levels of mRNA, protein, enzymatic activity and cell growth. IDO1 small inhibitory (si)RNA were created to target IDO1 specifically, and transfected into cells. SNA generation is currently underway. RESULTS: ANTICIPATED RESULTS: IDO1 is expressed in different human pediatric DIPG cells at the mRNA and protein levels. We created siRNA that specifically targets IDO1 and preliminary results show overall decrease of IDO1 at the mRNA and protein level. Generation of SNA is ongoing for targeted approach and improved blood brain barrier penetration & stability, with anticipated results that siIDO1-SNAs inhibit IDO1 expression and reduce tumorigenesis within brain tumor cells. DISCUSSION/SIGNIFICANCE OF IMPACT: The overall poor prognosis of children with DIPG combined with the lack of effective therapies, emphasizes the importance of understanding the IDO1 pathway and the potential effects of IDO1 inhibition for therapeutically-modulating these devastating tumors. Our research confirms IDO1 presence in DIPG, and the use of nanotechnology and development of siRNA-SNAs for IDO1 inhibition has the capability of direct translatability of therapeutically-valuable data.