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Unlike urinary tract infection (UTI), asymptomatic bacteriuria (ABU) should not be treated, with some exceptions such as pregnant women and patients who will undergo traumatic urologic interventions. However, there has been no clinically available marker for their differential diagnosis. Exosomes or small extracellular vesicles carry proteins contained in cells from which they are derived, thus having the potential as a biomarker of several diseases. On the basis of the hypothesis that the molecular signature of exosomes in urine may differ between UTI and ABU patients, we examined if urinary exosomes could serve as a marker for their differential diagnosis. Exosomes were isolated by ultracentrifugation or affinity-based method from cell culture medium of monocytic THP-1 and uroepithelial SV-HUC-1 cells and human urine. Protein expression was examined by Western blot analysis, ELISA, and CLEIA. The results showed that the levels of intracellular signalling molecules Akt and ERK and transcription factor NF-κB increased in exosomes isolated from THP-1 and SV-HUC-1 cells cocultured with Escherichia coli and/or treated with lipopolysaccharide. In urinary exosomes of UTI patients, Akt significantly diminished, and an exosomal marker CD9 showed a trend to decrease after treatment with antimicrobial agents. More importantly, Akt and CD9 levels in urinary exosomes were higher in UTI patients than in ABU patients, which was also observed after correction by urine creatinine. Collectively, these results suggest that Akt and CD9 in urinary exosomes could be useful markers for differential diagnosis of UTI and ABU., (© 2019 John Wiley & Sons Ltd.)

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.

Background/aim: Exosomes have been demonstrated to be useful non-invasive biomarkers for several cancers including prostate cancer. Since normal cells also secrete exosomes, isolation of cancer-derived exosomes from blood is a prerequisite for their better understanding. The aim of this study is to establish the method for isolation of prostate cancer-related exosomes from blood., Materials and Methods: Exosomes were collected from prostate cancer LNCaP and PC-3 cell lines by ultracentrifugation and by using magnetic beads conjugated with anti-CD9 antibody and anti-prostate-specific membrane antigen (PSMA) antibody. Prostate cancer-related exosomes were also isolated from the plasma of prostate cancer patients by anti-PSMA beads. Isolated exosomes were analyzed by western blotting., Results: Exosomes were isolated from LNCaP cells by ultracentrifugation, contained PSMA and androgen receptor (AR). AR was also detected in exosomes isolated from LNCaP cells by anti-PSMA and anti-CD9 beads, showing that AR is present in prostate cancer-related exosomes. The amount of CD9 in isolated exosomes was much higher in advanced and chemo-resistant prostate cancer patients than in prostate cancer patients without metastasis and healthy volunteers, indicating that patients with aggressive prostate cancer exhibit higher levels of prostate cancer-related exosomes in blood., Conclusion: The immunoaffinity-based method we developed is capable of isolating prostate cancer-related exosomes from blood, the use of which will enhance investigation processes on exosomes in prostate cancer., (Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Exosomes or extracellular vesicles have the potential as a diagnostic marker for various diseases including cancer. In order to identify novel exosomal markers for prostate cancer (PC), we performed proteomic analysis of exosomes isolated from PC cell lines and examined the usefulness of the marker in patients.Methods: Exosomes isolated by differential centrifugation from the culture medium of androgen-dependent LNCaP prostate cancer cell line and its sublines of partially androgen-independent C4, androgen-independent C4-2 and bone metastatic C4-2B were subjected to iTRAQ-based proteomic analysis. Exosomes were also isolated by immunocapture and separated by size exclusion chromatography and density gradient centrifugation. Protein expression was determined by Western blot analysis. GGT activity was measured using a fluorescent probe, γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG). Immunohistochemical analysis of tissues was performed using anti-GGT1 antibody.Results: Among proteins upregulated in C4-2 and C4-2B cells than in LNCaP cells, we focused on gamma-glutamyltransferase 1 (GGT1), a cell-surface enzyme that regulates the catabolism of extracellular glutathione. The levels of both GGT1 large and small subunits were elevated in exosomes isolated from C4-2 and C4-2B cells by differential centrifugation and by immunocapture with anti-CD9 or -prostate-specific membrane antigen (PSMA) antibody. In cell lysates and exosomes, GGT1 expression correlated with GGT activity. Size exclusion chromatography of human serum demonstrated the presence of GGT activity and GGT1 subunits in fractions positive for CD9. Density gradient centrifugation revealed the co-presence of GGT1 subunits with CD9 in exosomes isolated by differential centrifugation from human serum. Since GGT activity correlated with GGT1 expression in serum exosomes isolated by differential centrifugation, we measured serum exosomal GGT activity in patients. Unexpectedly, we found that serum exosomal GGT activity was significantly higher in PC patients than in benign prostatic hyperplasia (BPH) patients. In support of this finding, immunohistochemical analysis showed increased GGT1 expression in PC tissues compared with BPH tissues.Conclusions: Our results suggest that serum exosomal GGT activity could be a useful biomarker for PC. [ABSTRACT FROM AUTHOR]

Objectives Docetaxel is used as the first-line chemotherapy for castration-resistant prostate cancer (CRPC), but docetaxel resistance occurs in part owing to induction of P-glycoprotein (P-gp) encoded by multidrug resistance protein 1 (MDR1) gene. A recently developed taxane—cabazitaxel—has poor affinity for P-gp and is thereby effective in docetaxel-resistant CRPC. It has been recently demonstrated that exosomes in the body fluids could serve as a diagnostic marker because they contain proteins and RNAs specific to the cells from which they are derived. In this study, we aimed to investigate if P-gp in blood exosomes could be a marker to diagnose docetaxel resistance and select a taxoid for patients with CRPC. Methods and materials Exosomes were isolated by differential centrifugation from docetaxel-resistant prostate cancer (PC-3) cells (PC-3R) and their parental PC-3 cells and from the serum of patients. Silencing of P-gp was performed by small interfering RNA transfection. Protein expression was examined by Western blot analysis. Viability of cells treated with docetaxel or cabazitaxel was determined by water soluble tetrazolium salt (WST) assay. Results The level of P-gp was higher in exosomes as well as cell lysates from PC-3R cells than in those from PC-3 cells. Cabazitaxel effectively killed PC-3R cells, and MDR1 knockdown improved the sensitivity of PC-3R cells to docetaxel but not to cabazitaxel. The P-gp level in blood exosomes was relatively higher in clinically docetaxel-resistant patients than in therapy-naïve patients. Conclusions Our results suggest that detection of P-gp in blood exosomes, which is involved in resistance to docetaxel but not to cabazitaxel, could be useful to diagnose docetaxel resistance and select an appropriate taxoid for patients with CRPC—docetaxel or cabazitaxel. [ABSTRACT FROM AUTHOR]