Echanism by which EndoMT in EC produces EVs that may perhaps propagate angiostatic effects all through the AT vasculature in obesity. Funding: NIHR15NHLBI, American Heart AssociationAIREA.ISEV2019 ABSTRACT BOOKSymposium Session 9: EV Biogenesis II Chairs: Bong Hwan Sung; Graca Raposo Location: Level B1, Hall B 17:008:OT09.Unique exosome subtypes have distinct ESCRT-associated biology and handle tumour cell adaptation in vivo Shih-Jung Fana, Benjamin Kroegerb, Pauline Mariea, Esther Bridgesa, Kristie McCormicka, John Masona, Helen Sheldona, Claudia Mendesa, Mark Wainwrighta, John Morrisa, Adrian Harrisa, Clive Wilsona and Deborah C I. Goberdhana University of Oxford, Oxford, UK; Melbourne, Australiaa bFunding: This operate was funded by Cancer Study UK [C19591/A19076], the CRUK Oxford Centre Improvement Fund [C38302/A12278], BBSRC [BB/ K017462/1, BB/N016300/1, BB/R004862/1], John Fell Fund, Oxford, Wellcome Trust [MICRON; #091911, #107457], Royal College of Surgeons.Peter MacCallum Cancer Centre,OT09.Emerging part of L-type calcium channel-mediated calcium influx in regulating apoptotic bodies formation Thanh Kha Phana, Bo Shib, Niall Geogheganc, Kelly Rogersd and Ivan PooneaIntroduction: Determining the function of precise extracellular vesicle (EV) and exosome subtypes has proved difficult, in aspect due to the difficulty in untangling the mechanisms major to their generation. Strategies: We investigated the cell biology behind exosome formation making use of the large endosomal compartments presented by an in vivo fly model, and analysis in human HCT116 and other cancer cell lines. EV preparations have been also tested in vivo following injection in to human xenografts in mice. We analysed different EV preparations by mass spectrometry making use of Tandem Mass Tag Glucagon Receptor Proteins Species labelling to identify alterations in protein cargo of EVs in response to microenvironmental pressure. Benefits: Utilizing these complementary approaches, we show that microenvironmental anxiety, for instance glutamine depletion, leads to a switch in membrane trafficking in the classic late endosomal multivesicular endosomes to Rab11a-positive recycling endosomes and also the production of Rab11a-positive exosomes, which market cell growth under stress situations. This activity is suppressed by blocking Rab11a-dependent trafficking and ESCRT function. Our proteomics and fly information suggest that some ESCRTs are differentially involved in these two exosome-generating processes. Furthermore, mouse xenografts highlight roles for stress-induced EVs in escalating the turnover of tumour cells, leading to an increase in hypoxic anxiety, connected with choice for aggressive cells that can promote tumour progression. These stress-induced vesicles also have a potent impact on blood vessel development in vivo. Summary/Conclusion: We conclude that stressinduced EVs and exosomes made in Rab11a-positive recycling endosomes are involved in tumour adaptation.Division of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia; bDepartment of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia; cCentre for Dynamic Imaging, Walter and Eliza Hall Institute of Healthcare Analysis, Melbourne, Australia; d Centre for Dynamic Imaging, Walter and Eliza Hall Institute of Medical Study, Melbourne, Australia; eLa Trobe University, Bundoora, AustraliaIntroduction: Dying cells generally break into CD28 Proteins Accession smaller sized membrane-bound fragments, referred to as apoptotic.