Detection of Human c-Myc and EGFR Amplifications in Circulating Extracellular Vesicles in Mouse Tumour Models

Abstract

Essentially, all cells release extracellular vesicles (EVs) that end up in biofluids, including blood, and the contents of these EVs can provide a window into the status of the cells from which they are released. This is particularly interesting in cancer, since these EVs allow for ‘ex-vivo’ analysis of the properties of the tumours without the need for biopsy. Gene mutations, rearrangements, amplifications, and epigenetic changes in the transcriptome can be monitored in circulating EVs. In this study, we used two human tumour cell lines derived from an epidermoid carcinoma and a medulloblastoma, which had amplification for the epidermal growth factor receptor (EGFR) and c-Myc genes, respectively. Cells were implanted subcutaneously into immunocompromised mice, and levels of gene amplification in both groups of subcutaneous tumours were quantified. We then determined if elevated levels of transcripts for the human EGFR and c-Myc were represented in circulating EVs in tumour-bearing mice. The expression levels of both human EGFR (h-EGFR) and human c-Myc (h-c-Myc) mRNAs in circulating EVs correlated well with their amplified status in the tumours. This data provides further support to the idea that circulating EVs are a potential platform for tumour biomarkers.