👤 Yong Song Gho

Most cancer cells adopt a less efficient metabolic process of aerobic glycolysis with high level of glucose uptake followed by lactic acid production, known as the Warburg effect. This phenotypic transition enables cancer cells to achieve increased cellular survival and proliferation in a harsh low-oxygen tumor microenvironment. Also, the resulting acidic microenvironment causes inactivation of the immune system such as T-cell impairment that favors escape by immune surveillance. While lots of studies have revealed that tumor-derived EVs can deliver parental materials to adjacent cells and contribute to oncogenic reprogramming, their functionality in energy metabolism is not well addressed. In this study, we established prostate cancer cells PC-3AcT resistant to cellular death in an acidic culture medium driven by lactic acid. Quantitative proteomics between EVs derived from PC-3 and PC-3AcT cells identified 935 confident EV proteins. According to cellular adaptation to lactic acidosis, we revealed 159 regulated EV proteins related to energy metabolism, cellular shape, and extracellular matrix. These EVs contained a high abundance of glycolytic enzymes. In particular, PC-3AcT EVs were enriched with apolipoproteins including apolipoprotein B-100 (APOB). APOB on PC-3AcT EVs could facilitate their endocytic uptake depending on low density lipoprotein receptor of recipient PC-3 cells, encouraging increases of cellular proliferation and survival in acidic culture media via increased activity and expression of hexokinases and phosphofructokinase. The activation of recipient PC-3 cells can increase glucose consumption and ATP generation, representing an acquired metabolic reprogramming into the Warburg phenotype. Our study first revealed that EVs derived from prostate cancer cells could contribute to energy metabolic reprogramming and that the acquired metabolic phenotypic transition of recipient cells could favor cellular survival in tumor microenvironment. Show less

In this study we tested whether a protein corona is formed around extracellular vesicles (EVs) in blood plasma. We isolated medium-sized nascent EVs of THP1 cells as well as of Optiprep-purified platelets, and incubated them in EV-depleted blood plasma from healthy subjects and from patients with rheumatoid arthritis. EVs were subjected to differential centrifugation, size exclusion chromatography, or density gradient ultracentrifugation followed by mass spectrometry. Plasma protein-coated EVs had a higher density compared to the nascent ones and carried numerous newly associated proteins. Interactions between plasma proteins and EVs were confirmed by confocal microscopy, capillary Western immunoassay, immune electron microscopy and flow cytometry. We identified nine shared EV corona proteins (ApoA1, ApoB, ApoC3, ApoE, complement factors 3 and 4B, fibrinogen α-chain, immunoglobulin heavy constant γ2 and γ4 chains), which appear to be common corona proteins among EVs, viruses and artificial nanoparticles in blood plasma. An unexpected finding of this study was the high overlap of the composition of the protein corona with blood plasma protein aggregates. This is explained by our finding that besides a diffuse, patchy protein corona, large protein aggregates also associate with the surface of EVs. However, while EVs with an external plasma protein cargo induced an increased expression of TNF-α, IL-6, CD83, CD86 and HLA-DR of human monocyte-derived dendritic cells, EV-free protein aggregates had no effect. In conclusion, our data may shed new light on the origin of the commonly reported plasma protein 'contamination' of EV preparations and may add a new perspective to EV research. Show less