Double-stranded DNA in exosomes: a novel biomarker in cancer detection

作者：Basant Kumar Thakur, Haiying Zhang, Annette Becker, Irina R. Matei, Yujie Huang, Bruno Costa‐Silva, Yan Zheng, Ayuko Hoshino, Hélène Brazier, Jenny Xiang, Caitlin Williams, Ruth Rodriguez Barrueco, José M. Silva, Weijia Zhang, Stephen Hearn, Olivier Elemento, Navid Paknejad, Katia O Manova-Todorova, Karl Welte, Jacqueline Bromberg, Héctor Peinado, David C. Lyden · 发表于：Cell Research · 年份：2014 · DOI：10.1038/cr.2014.44 · 被引用次数：1605 · 研究领域：Extracellular vesicles in disease、MicroRNA in disease regulation、RNA Interference and Gene Delivery

Exosomes, small membrane vesicles (30-100 nm) of endocytic origin secreted by most cell types, contain functional biomolecules, which can be horizontally transferred to recipient cells 1 . Exosomes bear a specific protein and lipid composition, and carry a select set of functional mRNAs and microRNAs 2 . Recently, our group has shown that c-Met shed in exosomes can promote a proangiogenic and prometastatic phenotype in bone marrow-derived progenitor cells during melanoma progression 3 . In previous research, retrotransposon RNA transcripts, single-stranded DNA (ssDNA), mitochondrial DNA, and oncogene amplifications (i.e., c-myc) have been detected in microvesicles 4 , 5 , 6 . In this report, we provide evidence that tumor-derived exosomes carry double-stranded DNA (dsDNA), as demonstrated through two different approaches, using enzymatic methods (dsDNA-specific shrimp DNase) and physical/structural studies (atomic force microscopy, AFM). Furthermore, we show that exosomal DNA (exoDNA) represents the entire genome and reflects the mutational status of parental tumor cells. We also highlight the translational value of exoDNA in tumor-derived exosomes for its potential usefulness as a circulating biomarker in the early detection of cancer and metastasis. We demonstrate for the first time that the majority of DNA associated with tumor exosomes is double-stranded ( Figure 1A-1E ). Two types of DNA-specific detection assays were utilized to assess the nature and amount of DNA in th...