Delivery of DNA encoding RNA Therapeutics to Alter the Expression of Oncogenic Transcripts in Glioblastoma

Abstract

Glioblastoma multiforme (GBM) is the most common central nervous system (CNS) malignancy. The median survival is only 14 months. It is often characterized by the activation of one or more tyrosine kinase receptors, particularly epidermal growth factor receptor (EGFR). This receptor is dysregulated in about 60% of GBM tumors. EGFR amplification, over‐expression and constitutive activation leads to uncontrolled growth and proliferation of GBM. Although a great deal is known about the aberrant biology exhibited by EGFR‐activated GBM, the application of therapies against the biologic processes is limited by the blood‐brain barrier, which restricts systemically administered therapies from reaching the brain. Although anti‐sense RNAs and small interfering RNAs can be used to target and silence gene expression, exogenously expressed RNAs are susceptible to extracellular and intracellular nucleases as well as activation of cellular immunity against foreign nucleic acids. To bypass these degradatory mechanisms, we take advantage of a natural noncoding RNA gene architecture and the miRNA expression pathway along with an anti‐sense targeted approach to alter EGFR expression. In addition, we make use of a polycistronic delivery system to express RNAs targeting splicing and alternative poly‐A signal/G‐rich elements of the EGFR transcript. DNA delivery vectors were transfected into human GBM cell lines. Results show that our vectors were expressed at high levels with subsequent reduction in full‐length EGFR mRNA expression and concomitant activation of alternative therapeutic isoforms. Current strategies include using the polycistronic delivery mechanism to target additional oncogenic transcripts and adapting to a mouse model of GBM.Support or Funding InformationBristol‐Myers Squibb, Johnson & Johnson, and the Independent College Fund of New JerseyThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.