SAT-LB053 Investigating the Effects of Growth Hormone on Tumor-derived Exosome Output and Content

Exosomes, the extracellular vesicles originating from endosomes, modulate their target cell responses systematically by the nature of exosomal cargoes and their source tissues. The exosomes thus occupy a new-found critical role in the diagnoses of multiple pathologies especially cancer as well as in anti-cancer therapy. Growth hormone (GH) produced centrally by the pituitary gland or peripherally by several tissues, contributes to the regulation of growth and metabolism. We and others have shown that GH significantly promotes cancer progression, metastasis, and drug resistance- processes also regulated by exosomes from tumor tissues. In this report, we show for the first time that GH increases cancer cell exosome secretion as well as content which in turn potentially amplify tumor invasion and metastases. Our data show that GH treatment, significantly increases levels of exosomal markers in human melanoma SK-MEL-30 (skin cancer), PANC1 (pancreatic cancer) and H1299 (lung cancer) cell lines without a comparable increase in total cell numbers, indicating an increased exosome output. In addition, GH treatment induced changes in the tumor exosomal cargoes including Matrix Metalloproteinases (MMPs) and Transforming Growth Factor beta (TGFβ). Also, GHR as a hitherto unknown exosomal cargo was found in exosomes from H1299 and PANC1 cell lines. Exosomes are a hotbed of current biological research and have diverse potential as an indicator in diagnosis, as a drug target, or the drug itself. Our study identifies the previously unknown effects of GH on exosome secretion from cancer cells and the nature of the respective exosomal cargoes. Acknowledgement This work was supported in part by the State of Ohio’s Eminent Scholar Program that includes a gift from Milton and Lawrence Goll, by the AMVETS, and the Edison Biotechnology Institute at Ohio University. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.