TITLE:
Characterization of Exosomes in Plasma of Patients with Breast, Ovarian, Prostate, Hepatic, Gastric, Colon, and Pancreatic Cancers
AUTHORS:
Ming-Bo Huang, Meng Xia, Zhao Gao, Hu Zhou, Min Liu, Shan Huang, Rong Zhen, Jennifer Y. Wu, William W. Roth, Vincent C. Bond, Jian Xiao, Jing Leng
KEYWORDS:
Plasma, Mortalin, CD63, Cancer, Extracellular Vesicles, Exosomes
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.10 No.5,
May
29,
2019
ABSTRACT: Detection of circulating
tumor-specific DNA, RNA or proteins can be difficult due to relative scarcity.
Exosomes are extracellular vesicles, 30 - 150 nm in diameter derived from fusion of multivesicular bodies with the plasma
membrane. They are composed of a lipid bilayer membrane and contain proteins,
mRNA and miRNA. Exosomes are secreted by multiple cell types, including cancer
cells. However, there is a relative lack of information concerning the contents
of exosomes secreted by various tumor cell types. To examine exosomes in cancer, we collected blood
plasma samples from patients with breast, ovarian, prostate, hepatic, gastric,
colon, and pancreatic cancers. Exosomes were isolated from plasma and confirmed
by AchE assay, transmission electron microscopy and expression of the CD63
exosomal marker. Expression of AFP, CA724, CA153, CEA, CA125, CA199 and PSA
antigens were determined using an automated electro-chemiluminescence assay. Expression of the
tumor-related chaperone protein, mortalin,
was determined by Western blot analysis. Levels of exosome secretion were
variable among the different tumor types. Both exosome levels and mortalin expression within tumor cell exosomes
were higher than in healthy donors, except in pancreatic carcinoma, where
exosomes were elevated but mortalin expression
was not significantly different from healthy donors. Exosomes provide unique
opportunities for the enrichment of tumor-specific materials and may be useful as biomarkers and possibly as tools of cancer
therapies. Mortalin, which has been linked to cell proliferation and induction
of epithelial-mesenchymal transition of cancer cells, may be useful as a
prognostic biomarker and as a possible therapeutic target.