Comprehensive Characterization of Endometrial and Endometrial Cancer Exosomes

Document Type

Conference Proceeding

Publication Date


Publication Title

Reproductive Sciences


Introduction: Endometrial cancer (EC) is the most common malignancy diagnosed in the female reproductive tract. Exosomes are membrane-bound extrac vesicles produced in the endosomal compartment of most cells. Exosomes released by endometrium have been implicated in the early steps of embryo implantation. However, their role in uterine cancer remains poorly understood.

Methods: After obtaining IRB permission, specimens were collected from women undergoing clinically indicated surgery using a standardized protocol to gently lavage the endometrial cavity. Nanoparticles were isolated using Total Exosome Isolation Reagent (ThermoFisher). Particle size and structure were evaluated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Protein content was characterized by immunoblotting using commercially available antibodies for Hsp70, CD63, TSG101 and CD39. After isolating total RNA, patterns of non-coding RNA expression are profiled by NGS Sequencing (Novogene, Inc).

Results: Uterine lavage specimens contained large number of nanoparticles characterized by bilaminar membranes typical of exosomes. These particles typically ranged in size between 50-100 microns, although subpopulations of both larger (>100 micron) and smaller particles were also identified. No diferences in size or structure were observed when specimens recovered from women undergoing surgery for benign indications, endometrial intraepithelial neoplasia (EIN), G1-G2 or G3 endometrial adenocarcinoma (EC) or established endometrial cancer cell lines were compared (n=5 each). By Western blot, exosomes from all specimens were characterized by robust expression of CD63 and CD39. In contrast, robust TSG101 expression was observed in lavage specimens from G1/G2 and G3 endometrial cancer cases, sporadic specimens of healthy endometrium, but not established EC cell lines. HSP70 expression was observed in 3/6 EC specimens only. Electrophoresis indicates that RNA content of exosomes consists almost entirely of small (<50nt) transcripts. Patterns of non-coding RNA expression in exosomes distinguishing healthy endometrium, EIN and EC will be presented (n=8 each).

Conclusion: The distinct composition of exosomes in lavage specimens suggests that exosome biogenesis in endometrial cancers differs from healthy endometrium and established EC cell lines. These differences may be useful for understanding EC pathogenesis, and developing less invasive approaches for its diagnosis.



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