Large oncosomes overexpressing integrin alpha-V promote prostate cancer adhesion and invasion via AKT activation

Abstract

Background Molecular markers for prostate cancer (PCa) are required to improve the early definition of patient outcomes. Atypically large extracellular vesicles (EVs), referred as “Large Oncosomes” (LO), have been identified in highly migratory and invasive PCa cells. We recently developed and characterized the DU145R80 subline, selected from parental DU145 cells as resistant to inhibitors of mevalonate pathway. DU145R80 showed different proteomic profile compared to parental DU145 cells, along with altered cytoskeleton dynamics and a more aggressive phenotype. Methods Immunofluorescence staining and western blotting were used to identify blebbing and EVs protein cargo. EVs, purified by gradient ultra-centrifugations, were analyzed by tunable resistive pulse sensing and multi-parametric flow cytometry approach coupled with high-resolution imaging technologies. LO functional effects were tested in vitro by adhesion and invasion assays and in vivo xenograft model in nude mice. Xenograft and patient tumor tissues were analyzed by immunohistochemistry. Results We found spontaneous blebbing and increased shedding of LO from DU145R80 compared to DU145 cells. LO from DU145R80, compared to those from DU145, carried increased amounts of key-molecules involved in PCa progression including integrin alpha V (αV-integrin). By incubating DU145 cells with DU145R80-derived LO we demonstrated that αV-integrin on LO surface was functionally involved in the increased adhesion and invasion of recipient cells, via AKT. Indeed either the pre-incubation of LO with an αV-integrin blocking antibody, or a specific AKT inhibition in recipient cells are able to revert the LO-induced functional effects. Moreover, DU145R80-derived LO also increased DU145 tumor engraftment in a mice model. Finally, we identified αV-integrin positive LO-like structures in tumor xenografts as well as in PCa patient tissues. Increased αV-integrin tumor expression correlated with high Gleason score and lymph node status. Conclusions Overall, this study is the first to demonstrate the critical role of αV-integrin positive LO in PCa aggressive features, adding new insights in biological function of these large EVs and suggesting their potential use as PCa prognostic markers. Electronic supplementary material The online version of this article (10.1186/s13046-019-1317-6) contains supplementary material, which is available to authorized users.

Comprehensive palmitoyl-proteomic analysis identifies distinct protein signatures for large and small cancer-derived extracellular vesicles

“…L-EVs and S-EVs were isolated from cell culture media by differential ultracentrifugation followed by density gradient purification (Suppl. Figure 1C), in line with the most recent MISEV2018 guidelines 11 and previous studies that separated large oncosomes from exosomes 7,8,25,42 . Over 99% of the cells from which EVs were isolated were viable (Suppl.…”

Extracellular Vesicles as Signaling Mediators and Disease Biomarkers across Biological Barriers

“…While the mechanisms that mediate the biological effects of EVs on their cellular targets remain poorly known, it is clear that EVs are implicated in most, if not all, physiopathological processes, including signal transduction, cell growth, and differentiation, metabolic regulation, embryofetal development, organogenesis, tissue homeostasis and repair/regeneration, antigen presentation and immune response, ageing, pathogen-host interactions, carcinogenesis, tumor invasion/metastasis, cardiovascular dysfunction, etc. [9,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. The EV cargo, packaged within relatively stable membrane-bound structures, is sheltered from degradation by the extracellular enzymes present in biological fluids, and may therefore maintain biological stability over comparatively long periods of time [38].…”

“…These vehiculate enzymes involved in glucose, glutamine and amino acid metabolism, mitochondrial constituents, mitochondria-derived vesicles [92], and genomic/mitochondrial DNA from the tumor of origin [93]. Oncosomes may therefore modulate the metabolic and genetic potential of their target cells; additionally, they may confer proteolytic activity, promoting invasion/migration, and may influence organotropic metastatic spread [34,35,94], a process that may involve integrin signaling [34].…”

Extracellular Vesicles Involvement in the Modulation of the Glioblastoma Environment

“…Microvesicles have procoagulant roles and represent a form of secretion for IL1b. e function of MVs has also been proposed in the rheumatoid arthritis pathogenesis, as well as in the mechanisms associated with tumour proinvasive characteristics and in the induction of oncogenic cellular transformation and fetomaternal communication [43,52,53].…”

“…Several studies refer to a network of the EVs-mediated cellular interactions linked to cancer spreading [10,52,53] with a prion-like model. Extracellular vesicles originated by cancer cells induce tumour-promoting effects in nearby cells [66], releasing not only soluble factor and proteins, such as oncoproteins, ephrins, and chemokine receptors but also DNA, mRNAs, miRNAs, and other small noncoding RNAs that mediate specific signalling machineries related to dysregulated cell growth and hypoxic environment development [45,[67][68][69][70][71][72].…”