Towards establishing extracellular vesicle-associated RNAs as biomarkers for HER2+ breast cancer

Extracellular vesicles (EVs) are emerging as key players in breast cancer
progression and hold immense promise as cancer biomarkers. However,
difficulties in obtaining sufficient quantities of EVs for the
identification of potential biomarkers hampers progress in this area. To
circumvent this obstacle, we cultured BT-474 breast cancer cells in a
two-chambered bioreactor with CDM-HD serum replacement to significantly
improve the yield of cancer cell-associated EVs and eliminate bovine EV
contamination. Cancer-relevant mRNAs BIRC5 (Survivin) and YBX1, as well as
long-noncoding RNAs HOTAIR, ZFAS1, and AGAP2-AS1 were detected in BT-474
EVs by quantitative RT-PCR. Bioinformatics meta-analyses showed that BIRC5
and HOTAIR RNAs were substantially upregulated in breast tumours compared
to non-tumour breast tissue, warranting further studies to explore their
usefulness as biomarkers in patient EV samples. We envision this effective
procedure for obtaining large amounts of cancer-specific EVs will
accelerate discovery of EV-associated RNA biomarkers for cancers including
HER2+ breast cancer.