Abstract 6570: Characterization of diverse extracellular nanoparticles and tumorigenic relevance in hepatocellular carcinoma

Abstract Introduction: Tumor-derived extracellular nanoparticles termed exomeres (EM), distinct to small extracellular vesicles (sEV), act as critical mediators of the tumor microenvironment (TME) formation and are associated with tumor progression and therapy resistance in hepatocellular carcinoma (HCC). Methods: sEV and EM were isolated from various normal and cancer cell lines using serial ultracentrifugation. The physical and biomedical characterization of EM versus sEV was conducted through transmission electron microscopy (TEM) and mass spectrometry (MS) analysis. Potential molecular EM markers were identified based on the distinct proteomic profiles between sEV and EM. The tumorigenic potentials of HCC-EM were evaluated using in vitro functional assays and in vivo mice models. Relevant oncogenic mechanisms were studied according to the differential cargo contents of HCC- and normal-EM, as well as differential gene expression of the recipient cells by RNA sequencing. The effects of EM on cell cycle progression and metabolic dysregulation were investigated by flow cytometry and analytical metabolomic/lipidomic approaches. Results: The TEM and MS analysis demonstrated distinct morphological and protein differences between sEV and EM. GALNS and MAN2B1 were two proteins identified as potential EM markers, showing exclusive or significantly higher expression. Functionally, EM released from HCC cells, instead of normal hepatocytes, stimulated cell growth, motility and tumor development. The EM originated from human HCC cells exhibited increased WNT5A, LRP5, and LRP6 levels, activating the PI3K/AKT/mTOR pathway in recipient cells. In addition, EM derived from murine HCC cells were shown to accelerate cell cycle progression by shifting cells through the checkpoint into the G1 phase, and reconstitute the lipid pattern to be enriched with a very-long chained saturated fatty acid, which triggers the metabolic reprogramming. Conclusions: Collectively, our findings underscore the unique characteristics of EM as a nanoparticle subpopulation that differs from sEV, and that EM derived from HCC can play a significant role in tumorigenesis and metastasis. Citation Format: Jiaqi Lai, Cherlie Lot Yeung, Cui Le, Lavisha Korani, Tung Him Ng, Xiaoxin Zhang, Zhixian Chen, Ruiqi Ma, Chi Ming Che, Judy Wai Yam. Characterization of diverse extracellular nanoparticles and tumorigenic relevance in hepatocellular carcinoma [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 6570.