Bone metastasis remains poorly understood. Strategies: We isolated and purified exosomes by CD25/IL-2R alpha Proteins MedChemExpress ultracentrifugation, isolated total RNA from cells and total miRNA from exosomes, and analysed the amount of miR-375 by RTPCR. Exosome libraries from LNCaP cells and RWPE-1 cells had been sequenced and filtered with an Illumina HiSeqTM 2500 program. The activity of alkaline phosphatase, the extent of extracellular matrix mineralization plus the expression of osteoblast activity-related marker genes had been measured to evaluate osteoblast activity. Benefits: Morphological observation, particle size evaluation and molecular phenotyping confirmed that the isolated extracts contained exosomes. Differential expression evaluation confirmed the high expression of miR-375 in LNCaP cell-derived exosomes. We additional determined which exosomes could enter osteoblasts and raise their miR-375 level. Moreover, exosomal miR-375 could significantly promote the activity of osteoblasts. Summary/conclusion: This study lays the foundation for additional investigations around the function of exosomal miR-375 within the activation and differentiation of osteoblasts as well as the mechanism of bone metastasis in PCa. Funding: noneLBF01.02=OWP1.Colorectal cancer cell-derived exosome enhances microenvironmental angiogenesis via modulation of intracellular metabolism Atsushi Ikedaa, Satoshi Nagayamab and Koji Uedaca Cancer proteomics group, Cancer Precision Medicine Center, BTN1A1 Proteins Source Japanese Foundation for Cancer Analysis, Tokyo, Japan; bDepartment of Gastroenterological Surgery, Cancer Institute Hospital, Japanese FoundationIntroduction: For improvement of prognosis of colorectal cancer (CRC), detection at an earlier stage of CRC is crucial. Exosomes are nanovesicles secreted from plasma membrane, and have potential to be served as biomarker carriers. In this study, we performed proteomic profiling of exosomes secreted from viable CRC tissues. Approaches: To recognize early detection biomarkers for CRC, we performed extensive proteome analysis of tissue-exudative extracellular vesicles (Te-EVs), which had been obtained from culture media of freshly resected viable CRC tissue or adjacent standard mucosa (n = 17). Among the identified Te-EV proteins, we narrowed down the biomarker candidate by picking proteins that are statistically upregulated (p .05, fold modify 5.0) in Te-EVs from CRC tissues than those from adjacent normal tissues. Then we performed functional analysis from the biomarker candidate especially. Benefits: Extensive LC/MS evaluation identified 6149 Te-EV proteins, in which 641 proteins showed important upregulation in Te-EVs from CRC tissues (p . 05, fold transform 5. 0) compared to those from adjacent normal mucosa. We focused specifically on GAM (p = 7.0 ten, fold adjust = 7.4) as a novel biomarker candidate. GAM protein was significantly overexpressed in CRC tissues compared with adjacent normal mucosa. In EV-sandwich ELISA assay, the expression degree of GAM on plasma EVs from CRC patients was significantly greater than that from healthful donors in EV-sandwich ELISA assay (n = 133, p = 4.0 10). In addition, the uptake of GAM-overexpressing EVs enhanced vascular endothelial cell development and angiogenesis via modulation of nitric oxide metabolism. Summary/conclusion: EV-GAM could have good potential as a target for each CRC diagnosis and therapy. Our technique for identification of exosomal biomarker by proteomic profiling of Te-EV proteins is usually applied to other cancers.ISEV2019 ABSTRACT.