The Vaccine Effect of Extracellular Vesicles from Breast Cancer Cells

Abstract

Over 200,000 women are newly diagnosed each year with breast cancer, one of the most common forms of cancer among women1. Although the 5 year survival rate is higher than many other cancers, at around 90%, there are still tens of thousands that die each year from this devastating disease1, 3. Current forms of treatment for breast cancer, such as infrared radiation therapy, chemotherapy, and or tumor removal surgery, are generally effective at removing and killing the cancer2. However, there is no vaccine or any other preventative measure for breast cancer, apart from a few clinical trials, since it is unlike a virus that can be prevented with a specific viral protein-targeting vaccine4. Here, we hypothesize that extracellular vesicles (EVs) from cancerous cells can be used to create a potential vaccine-like effect in immune cells in vitro.

Our immune cell of choice to receive the cancerous EVs was the antigen-presenting dendritic cell (DC). Monocytes were treated with GM-CSF, IL-4, TNF, and ionomycin to make matured DCs. Through Western Blot analysis, we determined that EVs from the 4T1-eGFP mouse breast cancer cell line would be used in order to treat matured DCs with breast cancer EVs. EVs from 4T1-GFP cells contain high levels of tetraspanin CD63, a common EV marker. After treating DCs with the cancerous EVs for 5 days, we extracted the DC exosomes (dexosomes) in order to analyze their contents through another set of Western Blots. The findings from these western blots, which assayed for the presence of certain cytokines, will be discussed. In conclusion, 100K EVs may serve as a good potential set of protein/RNA complexes for vaccine purposes. Future research must verify these results with multiple sets of Western Blots, validate mass spectrometry data, monitor the treatment of DCs, and expand testing to animal studies in vivo.