Echanism by which EndoMT in EC produces EVs that may perhaps propagate angiostatic effects throughout the AT vasculature in obesity. Funding: NIHR15NHLBI, American Heart AssociationAIREA.ISEV2019 ABSTRACT BOOKSymposium Session 9: EV Biogenesis II Chairs: Bong Hwan Sung; Graca Raposo Place: Level B1, Hall B 17:008:OT09.Various exosome subtypes have distinct ESCRT-associated biology and control 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 work 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 particular extracellular vesicle (EV) and exosome subtypes has proved challenging, in portion because of the difficulty in untangling the mechanisms leading to their generation. Strategies: We investigated the cell biology behind exosome formation working with the large endosomal compartments supplied 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 distinctive EV preparations by mass spectrometry applying Tandem Mass Tag labelling to recognize changes in protein cargo of EVs in response to microenvironmental pressure. Final results: Working with these complementary approaches, we show that microenvironmental tension, for example glutamine depletion, results in a switch in membrane trafficking in the classic late endosomal multivesicular endosomes to PARP14 custom synthesis Rab11a-positive recycling endosomes plus the production of Rab11a-positive exosomes, which promote cell development below pressure circumstances. This activity is suppressed by blocking Rab11a-dependent trafficking and ESCRT function. Our proteomics and fly data recommend that some ESCRTs are differentially involved in these two exosome-generating processes. Additionally, mouse xenografts highlight roles for stress-induced EVs in growing the turnover of tumour cells, major to a rise in 5-HT6 Receptor Agonist Biological Activity hypoxic stress, related with choice for aggressive cells that can market tumour progression. These stress-induced vesicles also possess a potent effect on blood vessel growth in vivo. Summary/Conclusion: We conclude that stressinduced EVs and exosomes produced in Rab11a-positive recycling endosomes are involved in tumour adaptation.Department 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 Investigation, Melbourne, Australia; d Centre for Dynamic Imaging, Walter and Eliza Hall Institute of Health-related Investigation, Melbourne, Australia; eLa Trobe University, Bundoora, AustraliaIntroduction: Dying cells frequently break into smaller sized membrane-bound fragments, called apoptotic.