Abstract LB298: Simultaneous reprogramming of glioblastoma tumor cells and tumor-associated macrophages by tumor-suppressive microRNA

Abstract Therapeutic outcomes in glioblastoma (GBM) patients remain dismal due to its resistance to conventional therapies. Tumor-supportive tumor microenvironment (TME) that is educated by tumor cells through immune editing is not properly primed for the treatment. Targeted reprogramming of both tumor cells and tumor-associated macrophages (TAMs) is expected to prime the tumor cells and the immunosuppressive TME. Tumor suppressive microRNAs (miRNAs) have been proposed as the most suitable therapeutic target to perform the tumor reprogramming role. We recently identified miR-138 as a putative tumor suppressive miRNA that can reprogram GBM tumor. However, achieving the simultaneous targeted reprogramming of two distinct cell types is a complex challenge, demanding a selective delivery system to minimize adverse side effects. Previously, we demonstrated that extracellular vesicles (EVs) can serve as carriers for the selective delivery of small noncoding therapeutic RNAs into cancer cells through the EV surface labeling with cancer-targeting ligands. Here, we report that the trypsin digestion of EV surface can enhance their surface labeling efficiency with cancer targeting ligands, such as folate, with favorable bio-distribution and pharmacokinetic profiles in GBM mice model. The folate-labeled trypsinized EVs demonstrated a potential to selectively target folate receptor (FR) positive GBM cells and TAMs both in vitro and in vivo. The selective targeting of folate-labeled trypsinized EVs led to the targeted delivery of miR-138 into both GBM tumor cells and TAMs, achieving anti-tumor efficacy. Mechanism of action studies revealed that the ectopically delivered miR-138 inhibits its previously identified known target genes to reprogram tumor cell proliferation and macrophage polarization. To our knowledge, this is the first preclinical study attempting to simultaneously modulate tumor cells and innate immunity by delivering tumor suppressive miR-138 using the trypsinized EV-based RNA delivery system for the GBM treatment. Our study results can be rapidly translated into human clinical trials in combination with current immunotherapies. Citation Format: Grace Nguyen, MinHye Noh, Yulin Dai, Zhongming Zhao, Ji Young Yoo, Tae Jin Lee. Simultaneous reprogramming of glioblastoma tumor cells and tumor-associated macrophages by tumor-suppressive microRNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB298.