Prostate cancer-derived urine exosomes: a novel approach to biomarkers for prostate cancer

Abstract

Herein, we describe a novel approach in the search for prostate cancer biomarkers, which relies on the transcriptome within tumour exosomes. As a proof-of-concept, we show the presence of two known prostate cancer biomarkers, PCA-3 and TMPRSS2:ERG the in exosomes isolated from urine of patients, showing the potential for diagnosis and monitoring cancer patients status.

Figure 1

Restriction enzyme analysis of the positive PCR products. (A) Positive tumour samples (P1 and P2) for the TMPRSS2:ERG gene fusion showing fragment sizes after digestion with HaeII, 68 bp and 54 bp (right lane) and the undigested product, 122 bp (left lane). (B) Positive samples for the PCA-3 gene product before and after digestion with Sca1, fragment sizes after digestion with Sca1 were 90 bp and 62 bp (left lane), and the uncut fragment size was 152 bp (right lane).

Figure 2

Electron microscopy of microvesicles isolated from urine of healthy donor (A and B) and PCa patient (patient nr. 11, C and D). (A) Microvesicles from healthy donor displaying the typical size (150–500 nm) and ultrastructure of electron-dense and electron-lucent prostasomes (arrows). (B) At high magnification, note the limiting membrane (arrowheads) and the unstructured matrix (star) of prostasomes. (C) Urine microvesicles from PCa patient showing small size (30–100 nm) and cup-shaped morphology (arrowheads) characteristic of exosomes. (D) Immunoelectron micrograph showing the presence of the typical surface exosomal marker CD63 on the microvesicles (arrowheads). Bars: A, B 500 nm; C, D 100 nm.