Abstract 5070: Prostate-specific membrane antigen (PSMA) targeted multiplexed siRNA-mediated gene silencing of CD46 and PD-L1 in prostate cancer

Abstract

Abstract Small interfering RNA are suitable for gene silencing through a sequence-specific RNA interference process. The redundancy and complexity of molecular pathways in cancer create a need for multiplexed targeting that can be achieved with multiplexed siRNA delivery. Here we delivered multiplexed siRNA with a PSMA-targeted biocompatible dextran nanoparticle (NP) to downregulate CD46 and PD-L1 siRNA in PSMA expressing prostate cancer cells. The multiplexed gene targets selected, PD-L1 and CD46, play important roles in the escape of cancer cells from immune surveillance. PSMA is abundantly expressed by prostate cancer cells allowing prostate cancer specific delivery of the NPs. The NP was decorated with acid cleavable amine functional groups through acetal bonds that undergo degradation under acidic conditions providing rapid release of siRNA. Cell imaging and flow cytometry studies confirmed PSMA-specific delivery of CD46 and PD-L1 siRNA to high PSMA expressing PC-3 PIP cells. Immunoblot, qRT-PCR and flow cytometry confirmed downregulation of CD46 and PD-L1 following treatment with multiplexed siRNA at a concentration of 50 nM. These studies pave the way for delivering multiplexed siRNA to tumors in vivo to unmask tumors to the immune system using PSMA targeted biocompatible NPs. Citation Format: Zhihang Chen, Balaji Krishnamachary, Yelena Mironchik, Sangeeta R. Banerjee, Martin G. Pomper, Zaver M. Bhujwalla. Prostate-specific membrane antigen (PSMA) targeted multiplexed siRNA-mediated gene silencing of CD46 and PD-L1 in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5070.