Prostate (cancer)-derived exosomes.

Fels, C.A.M. van der (2014) Prostate (cancer)-derived exosomes. thesis, Medicine.

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Abstract

Background Exosomes are small (50-150 nm) vesicles secreted by virtually every cell types, including tumor cells. They contain a wide range of proteins and RNAs that represent their tissue origin. For this reason they are considered to be an upcoming diagnostic marker for prostate cancer. The marker has to be more specific than Prostate-specific antigen (PSA) and has to reduce the overdiagnosis and overtreatment of prostate cancer. In particular transmembrane proteins are an important part of the exosome; they are expected to be useful for isolating exosomes from body fluids. Objective The goal in this study was to isolate prostate cancer derived exosomes from urines. By determining the number of prostate cancer derived exosomes in urine samples of different patient populations it could be establish whether this is a measure of the presence and aggressiveness of prostate cancer. Materials & methods Urine samples of men with and without prostate cancer and women were collected in the Erasmus MC clinic. Some urines were collected after a digital rectal examination (DRE) was performed to increase the prostate fluid in urine. Supernatant of different cell lines was used for isolating exosomes by ultracentrifugation. Enzyme linked immunosorbent assay and Fluorescence-activated cell sorting were used to measure protein levels on exosomes in medium of cell lines, urine samples, and in pure exosome samples. Europium labeled antibodies directed against specific transmembrane proteins were used in these experiments (α-CD9-Eu, α-CD63-Eu, α-TMPRSS2-Eu, α-CD105-Eu, α-5T4-Eu, α-B7-H3-Eu, α-CD13-Eu and α-PPAP2A-Eu). Results CD9-Eu and especially CD63-Eu counts were significant elevated in post-DRE urine samples. CD63-Eu counts normalized to urinary PSA levels were significantly elevated in urine samples of men with prostate cancer compared to samples of men without prostate cancer. The antibodies directed against prostate (cancer) specific proteins showed a wide variance in protein levels on exosomes in all kind of samples. Conclusion Elevations in CD63-Eu counts after normalization to urinary PSA levels suggest there may be value in further studying CD63 as a useful protein in the search for a novel biomarker of prostate cancer. In this study, it was not possible to isolate specific prostate cancer derived exosomes from urine by using antibodies directed against prostate (cancer) specific proteins.

Item Type:	Thesis (Thesis)
Supervisor name:	Boerma, Dr. M.O. and Urologist Deventer Ziekenhuis
Supervisor name:	Vredenbregt – van den Berg, Ing. M.S. and Jenster, Prof.Dr.Ir. G.W. and Experimental Urology and Josephine Nefkens Institute and Erasmus MC Rotterdam
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:56
Last Modified:	25 Jun 2020 10:56
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/1704

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