Intratumoral Cellular Heterogeneity Critically Determines Extracellular Vesicle Uptake in Colorectal Cancer

Abstract The majority of colorectal cancer (CRC) patients carry mutations in the APC gene, which leads to an unregulated activation of the Wnt pathway. Extracellular vesicles (EV) are considered as potential therapeutic tools. Although CRC is a genetically heterogenous disease, the significance of the inter- and intra-tumor heterogeneity in EV uptake of CRC cells is not yet known. By using mouse and patient-derived organoids, the currently available best model of capturing cellular heterogeneity, we found that Apc mutation induces the expression of interferon-induced transmembrane protein 1 (Ifitm1), a membrane protein that plays a major role in cellular antiviral responses. Importantly, organoids derived from IFITM1high CRC cells contained more proliferating cells. Whereas we found no difference in the uptake of liposomes between IFITM1high and IFITM1low/− cells, IFITM1high cells had a markedly reduced uptake of fibroblast EVs as compared to IFITM1low/− cells. In contrast, there was no difference in the intensity of EV release between CRC subpopulations with high and low IFITM1 level. Importantly, the difference in cell proliferation between these two subpopulations disappeared in the presence of fibroblast-derived EVs, proving the functional relevance of the enhanced EV uptake by IFITM1low CRC cells. Collectively, we identified CRC cell subpopulations with functional difference in their EV, but not liposome uptake ability that must be taken into consideration when using EVs as therapeutic tools for targeting cancer cells.