Exosomes are virus-sized, membrane-bound particles released by all cells that are thought to carry information important for cell-cell communication. Exosomes are produced at high levels by cancer cells and contain DNA, RNA and proteins that could be useful for cancer screening, diagnostics and treatment response monitoring. A new study led by researchers at MD Anderson Cancer Center found that exosomes contain a core proteome of approximately 1,200 proteins common to exosomes from all cells. The researchers also discovered that syntenin-1 is the most abundant protein across all exosomes, making it a potential universal marker of exosomes. Such a protein marker makes it easier to isolate and study exosomes to clarify their function and to develop approaches for using exosomes in the clinic.
Candidates for exosomal inclusion biomarkers
and exclusion biomarkers validated by different isolation methods
a, The validated exosomal markers and exclusion markers candidates in exosomes purified using the three isolation methods in the three cell lines analysed. Protein abundance is expressed as log2-transformed SILAC ratios (exosome/super-SILAC standard) and the individual quantification values are depicted in the heat maps. Results from three biological replicates. b, STRING-based PPI network of the 22 ubiquitous and abundant exosomal proteins. c, Enriched GOCC, GOMF, GOBP, KEGG, Pfam and InterPro categories in the 22 exosomal marker candidates. d, Enriched GOMF, Pfam and InterPro categories in the cohort of low abundant exosomal proteins. e, Representation of the putative exosomal markers identified in our study. f, Representation of the putative exclusion markers identified in this study.