Abstract
The interplay between tumor-derived large extracellular vesicles (LEVs) and the immune system may contribute to tumor progression, particularly regarding the modulation of cytokine production by dendritic cells (DCs). This study aims to elucidate the effects of LEVs from human papillomavirus (HPV)-derived cervical cancer cell lines, CaSki and SiHa, in comparison with the HPV(-) cell line C33A, on the expression of IL-10, IL-12 and IL-1 by DCs. Furthermore, the regulatory mechanisms of miRNA cargo of LEVs from CaSki and SiHa and C33A on cytokine expression are assessed in this study.
A statistically significant decrease in IL-1β expression in supernatants from DCs co-cultured with CaSki and SiHa LEVs compared with C33A LEVs was measured, whereas no significant change in IL-10 and IL-12 expression was observed. Furthermore, our investigation showed that SiHa-derived LEVs contain a higher quantity and diversity of miRNAs related to inflammatory cytokines, particularly IL-1β, compared to those from CaSki cells.
The pathway enrichment analysis highlights that the presence of miR-181a-5p exclusively in the miRNA cargo of CaSki LEVs is linked to the negative regulation of the MAPK signalling cascade and to the observed suppression of IL-1β. This suggests a potential mechanism whereby CaSki LEVs diminish IL-1β levels through targeted miRNA delivery, facilitating immune evasion in the tumor microenvironment.
Conversely, the larger amount of miRNA cargo in SiHa LEVs appears to enhance IL-1β expression, indicating a complex interplay of cytokine regulation influenced by the quantity and composition of LEVs. Furthermore, we explore the role of apoptosis-driven IL-1β secretion, supported by evidence linking caspase-8 activation to IL-1β release in DCs, thus implicating additional pathways in cytokine modulation.
This study identifies critical differences in miRNA composition between LEVs from HPVpositive cervical cancer cell lines, underscoring their potential role in shaping immune responses and promoting tumor immune evasion. However, limitations include reliance on pre-prepared frozen samples, which restricted the replication of certain assays, and the unsuccessful LEV uptake assay, which hampered the validation of our findings.
These results provide that suggests an miRNA mediated mechanism by which HPVassociated tumor cells may manipulate DC function. This has implications for therapeutic interventions targeting LEV-induced immunosuppression. Future studies should focus on delineating the exclusive roles of miRNAs and other LEV cargo in modulating immune responses, potentially leading to novel treatment strategies for cervical cancer.