On-chip immunoelectrophoresis of extracellular vesicles released from human breast cancer cells.
Extracellular vesicles (EVs) including exosomes and microvesicles have attracted considerable attention in the fields of cell biology and medicine. For a better understanding of EVs and further exploration of their applications, the development of analytical methods for biological nanovesicles has been required. In particular, considering the heterogeneity of EVs, methods capable of measuring individual vesicles are desired. Here, we report that on-chip immunoelectrophoresis can provide a useful method for the differential protein expression profiling of individual EVs. Electrophoresis experiments were performed on EVs collected from the culture supernatant of MDA-MB-231 human breast cancer cells using a measurement platform comprising a microcapillary electrophoresis chip and a laser dark-field microimaging system. The zeta potential distribution of EVs that reacted with an anti-human CD63 (exosome and microvesicle marker) antibody showed a marked positive shift as compared with that for the normal immunoglobulin G (IgG) isotype control. Thus, on-chip immunoelectrophoresis could sensitively detect the over-expression of CD63 glycoproteins on EVs. Moreover, to explore the applicability of on-chip immunoelectrophoresis to cancer diagnosis, EVs collected from the blood of a mouse tumor model were analyzed by this method. By comparing the zeta potential distributions of EVs after their immunochemical reaction with normal IgG, and the anti-human CD63 and anti-human CD44 (cancer stem cell marker) antibodies, EVs of tumor origin circulating in blood were differentially detected in the real sample. The result indicates that the present method is potentially applicable to liquid biopsy, a promising approach to the low-invasive diagnosis of cancer.
Department of Bioengineering, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, Japan.
Takanori
T
Akagi
Department of Bioengineering, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, Japan.
Kei
K
Kato
Department of Bioengineering, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, Japan.
Masashi
M
Kobayashi
Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo Japan.
Nobuyoshi
N
Kosaka
Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo Japan.
Takahiro
T
Ochiya
Department of Bioengineering, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, Japan.
Takanori
T
Ichiki
D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D055252:Cell-Derived Microparticles / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D056656:Lab-On-A-Chip Devices; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D046208:Microchip Analytical Procedures