Abstract 6695: Lipid nanoparticles with cell specific CRISPR activity against cancer
Authors: Noah Richardson, Sanam Rezaei Benam, Samaneh Maleknia, Reza Shahbazi
Journal: Cancer Research (2025)

Abstract The most prevalent cancer in men is prostate cancer and is the second leading cause of cancer death in men. Initially, metastatic prostate cancer responds to androgen deprivation therapy (ADT) blocking the androgen receptor (AR) signaling pathway responsible for growth and proliferation. Resistance eventually develops however and although systemic androgens are minimal, the androgen receptor remains functional and drives prostate cancer growth in most patients. This advanced form of prostate cancer termed castration-resistant prostate cancer (CRPC) is incurable and largely driven still by the AR. Development of resistance is through several mechanisms including receptor duplications, intratumoral androgen synthesis, constitutively active point mutations, and AR splice variants that confer resistance to current therapies targeting the AR signaling axis The continued biological significance and reliance of AR signaling in CRPC has made the definitive knockout (KO) of the gene an enticing target. We have developed antibody coated lipid nanoparticles (LNP) to specifically direct CRISPR nanoformulations to cancer cells expressing targetable surface antigens. Our first target is PSMA-expressing CRPC C4-2B cells. Our PSMA-LNP CRISPR formulation has increased safety and specificity with both extracellular and intracellular prerequisites for CRISPR targeting and activity. Intracellular activation of the CRISPR sgRNA complex is mediated by sensing cell-specific miRNA uniquely identified in malignant cells. We have screened miRNA databases and C4-2B cell lines identifying specific miRNA not expressed significantly in other healthy tissues. Using miRNA-flanked sgRNA CRISPR formulations our system once shuttled to PSMA expressing C4-2B cells allows assembly of Cas9 protein and sgRNA in a cell-specific manner causing AR knock out and cell death. In vitro PSMA-LNP delivery of unmodified guides demonstrate 60-95% gene editing efficiency analyzed by T7EI and TIDE analysis in C4-2B cells and control cells. Next using miRNA-flanked sgRNA CRISPR formulations we demonstrate preferrable editing in targeted cancer cell lines. Our time-lapse Incucyte live cell analysis shows preferential targeting of PSMA-LNP to C4-2B cell lines in comparison to control malignant and primary cell lines. Currently, we are continuing our studies through in vivo analysis of PSMA-LNP delivery and gene editing specificity in a CRPC mouse model utilizing our unique CRISPR LNP formulation in addition to exploring other gene targets controllable by microRNA sensing CRISPR therapeutics. Our findings demonstrate the feasibility of targeted CRISPR gene editing to treat prostate cancer and a platform for cancer-cell gene targeting across multiple cancers. Citation Format: Noah Richardson, Sanam Rezaei Benam, Samaneh Maleknia, Reza Shahbazi. Lipid nanoparticles with cell specific CRISPR activity against cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6695.