Abstract 2790: Exosomes as nanocarriers for biomolecules and potential diagnostic targets in cancer
Authors: Anilkumar Adithya , Lopez Samantha , Leslie Sophia , Doxtater Kyle , Chauhan Neeraj , Hafeez Bilal , Yallapu Murali , Jaggi Meena , Chauhan Subhash , Tripathi Manish 
Published: June 2022

Introduction: The tumor microenvironment is a dynamic domain and communication hub for signaling molecules, contributing to proliferative and metastatic behaviors observed in cancerous tissues. Intercellular interactions are commonly mediated through extracellular vesicles that carry vital information for growth and survival, a feature that is highly advantageous for cancer cells to hijack. Hepatocellular carcinoma (HCC) is one of the most rapidly increasing types of cancer in the United States. Often aggressive, HCC arises from the uncontrollable division of hepatocytes, which may disrupt the regular functions of the liver and other organs. Identifying biomarkers is essential to potentiate drug treatments while minimizing chances of metastasis, recurrence, and mortality. Highly proliferative cells are known to secrete exosomes containing tumor-enhancing biomolecules that contribute to cancerous progression. Thus, analyzing exosomal cargo in serum is especially attractive for early diagnostics, profiling, and therapeutic purposes. We have explored potential oncogenic lncRNAs and extracellular signaling proteins in HCC and conducted phenotypic studies to observe their mode of action.

Methods: HCC cell lines were propagated in EMEM containing exosome-free FBS. Exosomes were harvested with ThermoFisher Total Exosome Isolation Reagent from cell culture media, then resuspended in PBS. Zetasizer was used to measure the sizes of harvested exosomes, and western blot analysis was used to confirm exosomal markers. UCA1 and MALAT1 were checked via RTPCR via exosomes spiked with bacterial RNA as the loading control. Bradford assays were performed on exosomes lysed with RIPA for quantifying cargo proteins. Exosomal POTE-2 was observed through western blot analysis, in addition to ELISAs to identify their presence in media. Phenotypic studies were performed using isolated exosomes.

Results: The isolated exosomes were within the size range of 40-200nm, with a negative charge. The western blot of the exosomal markers confirmed their purity. RTPCR results showed LncRNAs MALAT1 and lncRNA UCA1 present in exosomes, whereas POTE-2 protein presence was confirmed with western blot. Phenotypic studies from the isolated exosomes are in progress.

Conclusions: Exosomes in serum are easily accessible biomolecules making them functional, less invasive targets for profiling, diagnostics, and therapeutics via liquid biopsies. Exosome-mediated delivery of lncRNAs MALAT1 and UCA1 to primary CRC cells has been found to promote malignancy. We have verified their presence in exosomes secreted by metastatic cell lines, in addition to oncoprotein POTE-2, which hold numerous significances for our phenotypic studies. These findings reaffirm exosomes as essential contributors to disease pathogenesis and present them as promising targets for diagnostics and treatment.

Citation Format: Adithya Anilkumar, Samantha Lopez, Sophia Leslie, Kyle Doxtater, Neeraj Chauhan, Bilal Hafeez, Murali Yallapu, Meena Jaggi, Subhash Chauhan, Manish Tripathi. Exosomes as nanocarriers for biomolecules and potential diagnostic targets in 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 2790.