Pancreatic cancer extracellular vesicles stimulate Schwann cell activation and perineural invasion in vitro via IL-8/CCL2

Abstract Purpose Pancreatic ductal adenocarcinoma (PDAC) remains a leading cause of cancer-related deaths, and perineural invasion (PNI), in which cancer cells infiltrate nerves, enables metastasis in most patients. PNI is largely attributed to Schwann cells (SC) that, when activated, accelerate cancer cell migration towards nerves. However, this cancer-associated reprogramming is generally under-appreciated. Additionally, tumor extracellular vesicle (EV) facilitation of cancer aggravation is well documented, but more investigation is required to better understand their role in PNI. Here, we assessed whether PDAC EVs mediate PNI via SC activation using tissue-engineered in vitro platforms and PANC-1 and HPNE human cell lines as models. Methods NanoSight, Luminex®, and proteomic-pathway analyses characterized tumor (PANC-1) and healthy cell (HPNE) EVs. Human Schwann-like cells (sNF96.2) were embedded in decellularized nerve matrix hydrogels and then treated with EVs and a cargo-function-blocking antibody. Immunofluorescence and Luminex® multiplex assays assessed Schwann cell activation. Subsequently, sNF96.2 cells were co-cultured with EVs and either PANC-1 or HPNE cells; Transwell® invasion assays with SC-conditioned media were also conducted to establish a mechanism of in vitro PNI. Results PANC-1 EVs contained higher levels of interleukin-8 (IL-8) signaling-associated proteins than HPNE EVs. Within nerve-mimetic in vitro testbeds, PANC-1 EVs promoted sNF96.2 activation per cytoskeletal marker alterations and secretion of pro-tumorigenic cytokines, e.g., chemokine ligand-2 (CCL2), via IL-8 cargoes. Furthermore, the IL-8/CCL2 axis heightened PANC-1 invasiveness. Conclusion These findings highlight the potential role of PDAC EVs in PNI, which necessitates continued preclinical assessments with increased biodiversity to determine the efficacy of targeting IL-8/CCL2 for PNI.