Abstract 717: Novel potent antisense oligonucleotides targeting transforming growth factor beta1 (TGF-β1)

Transforming growth factor beta (TGF-β) is a key member of a large family of cytokines, which play critical, pleiotropic roles in the pathophysiology of various human diseases, such as cancer, inflammation, autoimmune disease, and cirrhosis/fibrosis. TGF-β1, -2 and -3 isoforms are cytokines encoded by different genes but sharing strong sequence and structure homology. They function as the primary mediators of TGF-β signaling via both non-canonical and canonical signaling pathways. In Oncology, TGF-β isoforms are associated with a wide range of biological processes such as tumor cell invasion and migration, angiogenesis, immunosuppression, as well as regulation of tumor stem cell properties. Hence, blocking the TGF-β signaling pathway may have a multifold therapeutic benefit in Oncology, although therapeutic relevance of the respective TGF-β isoforms remains poorly documented. In order to evaluate the specific biological relevance of TGF-β1 isoform in cancer, we have initiated an extensive discovery program for identification of antisense oligodeoxynucleotide constructs selectively inhibiting expression of the TGF-β1 ligand. Based on the sequence of the human TGF-β1 mRNA, more than 150 Locked Nucleic Acid (LNA)-modified gapmers were designed, synthesized and tested in cell-based assays. Highly potent and selective TGF-β1 constructs were identified and selected based on efficient suppression of TGF-β1 mRNA/protein expression in different human and rodent tumor cell lines, and in human Peripheral Blood Mononuclear Cells (PBMCs). Effective target downregulation was demonstrated after lipofectamine aided-transfection (sub-nM concentration range), but also in the absence of any transfection agent (gymnotic delivery) at sub-µM concentrations. Selected TGF-β1 specific oligonucleotides were further tested in relevant animal xenograft models and strong target inhibition was also observed following systemic administration. Further details of this discovery program will be discussed and pharmacology properties and features of potent and selective TGF-β1 antagonists will be presented. Citation Format: Frank Jaschinski, Hanna Korhonen, Stephan Braun, Katja Wosikowski, Michel Janicot. Novel potent antisense oligonucleotides targeting transforming growth factor beta1 (TGF-β1). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract n