Imaging and tracking of tumor extracellular vesicles to unravel the progression of ovarian carcinoma using fluorescent membrane probes

Tumor extracellular vesicles (EVs) exert vital role in mediating intercellular communication. Investigation on the function of EVs will contribute to understanding of EV pathophysiology in cancer development. However, direct visualizing the behavior of EVs in vivo still faces challenges. In this study, we develop fluorescently labelled EVs derived from ovarian carcinoma (OC-EVs) utilizing lipid dye and protein-based membrane probes, which are investigated in living cells and mice models by high-resolution fluorescence imaging and ultrasonic imaging. Both membrane probes exhibit high labelling efficiency of EVs and good compatibility in vivo. The rapid internalization of individual OC-EVs by different single living cells are monitored, together with the complex and bidirectional exchange of EVs between normal and cancer cells. Furthermore, the enrichment of OC-EVs in ovary is recorded, indicating the homing targeting capability of EVs. For more precise observation of the homing process, in vivo ultrasonic imaging and fluorescence imaging are performed to evaluate the rapidly growing ovarian tumor after administrating OC-EVs. The results show that OC-EVs can accelerate tumor growth and promote the metastasis of primary tumors in mice, which provides valuable information in understanding the development of ovarian carcinoma and pursuing potential solution for improved treatment. [Display omitted] •Both lipid membrane probe and genetically encoding method allow for stable and specific staining of EVs.•Ovarian cancer EVs are rapidly internalized by various cells in vitro.•Visualizing and tracking of tumor EVs in vivo using fluorescence and ultrasonic imaging.•In vivo biodistribution reveals the main metabolization organs of liver and kidney.•First visualized evidence of tumor EVs in promoting ovarian tumor progression.