Tumor Progression Induces Alterations to Extracellular Vesicle Populations and Neutrophil Extracellular Trap-Supporting Functionality

Olivia Miller*, Hunter Snoderly and Margaret Bennewitz, Erma Byrd Biomedical Research Center, West Virginia University, Morgantown, WV 26506

Field (Broad Category): Engineering (Health Sciences) 

Student’s Major: Biomedical Engineering 

Every two minutes a woman is diagnosed with breast cancer, accounting for approximately 15.2% of new cancer cases in the US. Cancer-related mortality is commonly attributed to metastasis; understanding the mechanisms by which this occurs is critically important to improving patient outcomes. Metastasis has been noted to be facilitated by processes involving the interaction of neutrophils, neutrophil extracellular traps (NETs), and extracellular vesicles (EVs). Biomarkers for both EVs and NETs are markedly elevated in breast cancer patients. NETs form via NETosis as a response to inflammation or infection from extruded neutrophil DNA in web-like structures. NETs can be induced via EV-mediated activation of neutrophils and can arrest circulating tumor cells to facilitate metastasis. However, the role of EVs in contributing to this process is ill-defined. In this study, 4T1 murine mammary carcinoma cells were orthotopically injected into 35 mice, with IVIS performed weekly for 5 weeks to monitor tumor growth. Plasma, lung, liver, and primary tumor were collected from n=7 mice weekly, with EVs subsequently isolated from plasma. EVs from each group were used to stimulate neutrophils from healthy mice in vitro; their potential to induce NETosis was measured compared to 4T1 EVs derived from conditioned cell culture medium. Electron microscopy and NanoSight Tracking Analysis (NTA) were utilized to validate morphological differences in EV populations. We hypothesize that EVs from timepoints correlating with the onset of distant organ metastases will display enhanced induction of NETosis compared to EVs from timepoints either closer to primary tumor establishment or after metastatic occurrence. 

Funding: 

Program/mechanism supporting research/creative efforts: WVU's Research Apprenticeship Program (RAP) & accompanying HONR 297-level course