title: Integrin β4 and vinculin contained in exosomes are potential markers for progression of prostate cancer associated with taxane-resistance.
abstract: Treatment with taxanes for castration-resistant prostate cancer often leads to the development of resistance. It has been recently demonstrated that exosomes present in the body fluids contain proteins and RNAs in the cells from which they are derived and could serve as a diagnostic marker for various diseases. In the present study, we aimed to identify proteins contained in exosomes that could be markers for progression and taxane-resistance of prostate cancer. Exosomes were isolated by differential centrifugation from the culture medium of taxane-resistant human prostate cancer PC-3 cells (PC-3R) and their parental PC-3 cells. Isolated exosomes were subjected to iTRAQ-based quantitative proteomic analysis. Exosomes were also isolated from the culture medium by using anti-CD9 antibody-conjugated magnetic beads. Protein expression was knocked down by siRNA transfection followed by analysis of the silencing effects. Proteomic analysis showed that integrin β4 (ITGB4) and vinculin (VCL) were upregulated in exosomes derived from PC-3R cells compared to PC-3 cells. The elevation of ITGB4 and VCL was confirmed in exosomes captured by anti-CD9 antibody from the culture medium of PC-3R cells. Silencing of ITGB4 and VCL expression did not affect proliferation and taxane-resistance of PC-3R cells, but ITGB4 knockdown attenuated both cell migration and invasion and VCL knockdown reduced invasion. Our results suggest that ITGB4 and VCL in exosomes could be useful markers for progression of prostate cancer associated with taxane-resistance, providing the basis for development of an exosome-based diagnostic system.
authors.affiliation: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan.
authors.forename: Kyojiro
authors.initials: K
authors.lastname: Kawakami
authors.affiliation: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Fujita
authors.affiliation: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Gifu 501-1193, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Gifu 501-1193, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Mizutani
authors.affiliation: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Gifu 501-1193, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kameyama
authors.affiliation: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Tsumoto
authors.affiliation: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Miura
authors.affiliation: Department of Urology, Gifu University Graduate School of Medicine, Gifu, Gifu 501-1193, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Deguchi
authors.affiliation: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Ito
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D045744:Cell Line, Tumor; D018450:Disease Progression; D055354:Exosomes / Q000378:metabolism*; D006801:Humans; D039663:Integrin beta4 / Q000378:metabolism*; D008297:Male; D064129:Prostatic Neoplasms, Castration-Resistant / Q000378:metabolism* / Q000473:pathology; D040901:Proteomics / Q000379:methods; D043823:Taxoids / Q000494:pharmacology*; D015854:Up-Regulation; D016596:Vinculin / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C059834:ITGB4 protein, human; D039663:Integrin beta4; D043823:Taxoids; C488955:VCL protein, human; D016596:Vinculin