Conclusions
Our findings support the role of metabolic transporters within tumor-derived EVs in reshaping the tumor microenvironment to promote therapy resistance, which could have potential diagnostic, prognostic, and therapeutic implications.
Methods
Differential centrifugation-based methods were used to isolate EVs from established cell lines and human plasma. TMT labeling proteomics analysis of EVs revealed an abundance of metabolic transporter proteins. Increased expression of SLC1A5 in EVs of patient-derived plasma and cell lines rendered resistant to tyrosine kinase inhibitors and its relationship with progression-free survival was assessed using Kaplan-Meier survival plot. Gene knockdown and overexpression of SLC1A5 were used to validate its effect on Tyrosine kinase inhibitor (TKI) resistance. Co-culture assays using inserts was used to evaluate the effect of resistant EVs on normal fibroblasts and epithelial cells. Next, mouse-derived tumor slices (MDTS) were cultured in vitro to assess the effect of resistant EVs.
Results
We report here that TKI-sensitive cells are rendered resistant upon incubation with EVs derived from TKI-resistant cell lines. Metabolic transporters, in particular SLC1A5 and SLC25A5, are upregulated in EVs derived from TKI-resistant cells and plasma from patients harbouring TKI-resistant tumors and in TKI-resistant cell lines. Furthermore, we also provide evidence for the increased abundance of pSTAT3 and the stemness marker ALDH1A1 upon EV-induced resistance. Notably, resistant EVs trigger phenotypic and functional switching of lung-derived fibroblasts into tumor-associated fibroblasts, significantly increasing their migratory and invasive capacities. Conclusions: Our findings support the role of metabolic transporters within tumor-derived EVs in reshaping the tumor microenvironment to promote therapy resistance, which could have potential diagnostic, prognostic, and therapeutic implications.