[Establishment and identification of the near-infrared fluorescence labeled exosomes in breast cancer cell lines].

Exosomes, a population of extracellular membrane vesicles of 30-100 nm in diameter, play important roles in cell biological functions, intercellular signal transduction and especially in cancer diagnosis and therapy. To better apply exosomes in mechanistic study of breast cancer signal transduction, we constructed recombinant eukaryotic expression vector expressing the near-infrared fluorescence protein and CD63 fusion protein through cloning iRFP682 gene and exosomal marker protein CD63 gene into plasmid containing the ITR of AAV. The constructed plasmids were co-transfected with helper plasmid in AAV-293 cell lines and were packaged into rAAV. After titer measurement, the recombinant plasmids were transfected into breast cancer cell lines. The cell lines that stably expressing near-infrared fluorescence protein were selected by fluorescence. Through isolation, purification and identification, we finally obtained a new biomarker: iRFP682 labeled exosomes secreted by breast cancer cell lines, which could be used in further studies of the distribution and signal transduction of exosomes in breast cancer microenvironment.