Abstract 1346: Combined role of interleukin-15 stimulated natural killer cell-derived extracellular vesicles and carboplatin in Osimertinib resistant H1975 lung cancer with EGFR mutations
Authors: Nathani Aakash , Sun Li , Khan Islauddin , Aare Mounika , Bagde Arvind , Li Yan , Sachdeva Mandip 
Published: March 2024

Extracellular vesicles (EVs) derived from immune cells (e.g., NK cells, dendritic cells) may be able to treat malignancies that are resistant to other treatments (e.g., chemotherapy) relying on the hypothesis that EVs carry almost the same cargo of the parent cells. In this study, we evaluated IL-15 stimulated natural killer cell-derived EVs (NK-EVs) as therapeutic agents in vitro and in vivo in Osimertinib resistant lung cancer (H1975R) with EGFR mutations(L858R). NK-EVs were isolated by ultracentrifugation and nanoparticle tracking analysis revealed a size distribution of 89.5 ± 3.4 nm, zeta potential of -31.38 ± 0.25 mV. Atomic force microscopy imaging revealed vesicles with a spherical form and comparable sizes, meeting the criteria of exosomal EVs. Further, western blot studies demonstrated the presence of regular EV markers along with specific NK markers (perforin and granzyme). EVs were also characterized by using proteomic analysis which demonstrated that EVs had proteins for natural killer cell mediated cytotoxicity (Granzyme B) and T cell activation (Perforin and Plastin-2). Gene oncology (GO) analysis also showed that these are differentially expressed proteins (DEPs) that are involved in programmed cell death and positive regulation of cell death. Further, isolated NK-EVs (1*1011 particles/mL) were cytotoxic to H1975R cells in vitro with 55% and 68% cell viability in 2D and 3D cell cultures respectively against control. Carboplatin’s IC50 was reduced by approximately 1.9 and 1.7-fold (p less than 0.001) in 2D and 3D cell culture respectively when combined with NK-EVs. The EVs were then combined with carboplatin (25 mg/kg) and administered by i.p. route to H1975R tumor xenografts and significant reduction in tumor volume in vivo (≈1000 mm3 compared to ≈2000 mm3 of control group, p less than 0.001) was observed after 10 days. Our findings show for the first time that NK-EVs target the PD-L1/PD-1 immunological checkpoint and induce apoptosis and anti-inflammatory response by downregulation of SOD2, PARP, BCL2, SET, NF-κB and TGF-ß. MicroRNAs regulating cytotoxic proteins like perforin, granzyme and plastin were also identified using sequencing and the miRNAs: hsa-miR-5193/149-5P/3133/193-5p are picked for further studies. These miRNAs have been encapsulated in NK-EVs by electroporation and will be evaluated against Lung PDX xenografts along with carboplatin loaded NK-EVs. These miRNAs are directly involved in T cell or NK cell mediated cytotoxicity and are being currently investigated. The ability to isolate functional NK-EVs on a large scale and using them with

platinum-based drugs may lead to new clinical applications. The results of the present study suggest the possibility of the combination of NK-cell-derived EVs and carboplatin as a viable immunochemotherapeutic strategy for resistant cancers.

Citation Format: Aakash Nathani, Li Sun, Islauddin Khan, Mounika Aare, Arvind Bagde, Yan Li, Mandip Sachdeva. Combined role of interleukin-15 stimulated natural killer cell-derived extracellular vesicles and carboplatin in Osimertinib resistant H1975 lung cancer with EGFR mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1346.