Abstract 5088: Tumor penetrating RNA delivery for therapeutic benefit of pancreatic cancer

Abstract

Abstract Pancreatic cancer remains a deadly disease with a median survival of less than one year, in part because we lack effective therapeutic strategies. Mutations of the oncogene KRAS and the tumor suppressor genes TP53, INK4A, and DPC4 play important roles in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC); however, these driver events have proven to be challenging targets for drug development. RNA interference through small interfering RNA (siRNA) delivery has the potential to have an impact on silencing ‘undruggable’ targets; however, siRNA delivery in tumors has been challenging in general and worsened in PDAC by the stromal barriers to drug delivery. Herein, we integrated biomedical engineering, materials science, and pre-clinical investigation to establish a novel class of tumor-penetrating nanoparticles (TPNs) to enhance delivery of siRNAs in PDAC for therapeutic benefit. Specifically, we adapted self-assembled nanoparticles comprised of siRNA complexed with tandem tumor-penetrating and membrane-translocating peptides, which enabled the specific delivery of siRNA deep into the tumor parenchyma. Specifically, to establish efficacious siRNA delivery vehicles, we characterized and selected tandem peptides that incorporate novel tumor-penetrating peptide domains known to target PDAC in mice. In parallel, we optimized the particle stability through incorporation of hydrophilic molecules, focusing on achieving desirable pharmacokinetic properties which will reduce off-target delivery and increase potency of a given siRNA dose. The resulting TPNs carry siRNA into the cytosol of monolayer cultures of tumor cells, and also exhibit penetration in pancreas organoids derived from primary mouse and human tumors. As a proof-of-concept, we used TPN in vivo to knockdown KRAS in a murine PDAC model, using subcutaneously-implanted, autochthonous KRASG12D/+p53-/- tumors. Treatment of tumor-bearing mice with systemically administrated KRAS-specific TPNs suppressed the growth of established tumors. With the delivery platform established, the ongoing goals of this project are to identify siRNA targets that synergize with the suppression of oncogenic KRAS, and to validate synthetic lethal targets by interfering with signature PDAC driver events uncovered by functional genomic efforts. Together, these studies will provide a foundation for translational studies involving new targets and delivery technology in pancreatic cancer. Citation Format: Liangliang Hao, Justin Lo, Sangeeta Bhatia. Tumor penetrating RNA delivery for therapeutic benefit of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5088. doi:10.1158/1538-7445.AM2017-5088