Back to Search
Start Over
Database-augmented Mass Spectrometry Analysis of Exosomes Identifies Claudin 3 as a Putative Prostate Cancer Biomarker
- Source :
- Molecularcellular proteomics : MCP. 16(6)
- Publication Year :
- 2017
-
Abstract
- In prostate cancer and other malignancies sensitive and robust biomarkers are lacking or have relevant limitations. Prostate specific antigen (PSA), the only biomarker widely used in prostate cancer, is suffering from low specificity. Exosomes offer new perspectives in the discovery of blood-based biomarkers. Here we present a proof-of principle study for a proteomics-based identification pipeline, implementing existing data sources, to exemplarily identify exosome-based biomarker candidates in prostate cancer. Exosomes from malignant PC3 and benign PNT1A cells and from FBS-containing medium were isolated using sequential ultracentrifugation. Exosome and control samples were analyzed on an LTQ-Orbitrap XL mass spectrometer. Proteomic data is available via ProteomeXchange with identifier PXD003651. We developed a scoring scheme to rank 64 proteins exclusively found in PC3 exosomes, integrating data from four public databases and published mass spectrometry data sets. Among the top candidates, we focused on the tight junction protein claudin 3. Retests under serum-free conditions using immunoblotting and immunogold labeling confirmed the presence of claudin 3 on PC3 exosomes. Claudin 3 levels were determined in the blood plasma of patients with localized (n = 58; 42 with Gleason score 6–7, 16 with Gleason score ≥8) and metastatic prostate cancer (n = 11) compared with patients with benign prostatic hyperplasia (n = 15) and healthy individuals (n = 15) using ELISA, without prior laborious exosome isolation. ANOVA showed different CLDN3 plasma levels in these groups (p = 0.004). CLDN3 levels were higher in patients with Gleason ≥8 tumors compared with patients with benign prostatic hyperplasia (p = 0.012) and Gleason 6–7 tumors (p = 0.029). In patients with localized tumors CLDN3 levels predicted a Gleason score ≥ 8 (AUC = 0.705; p = 0.016) and did not correlate with serum PSA. By using the described workflow claudin 3 was identified and validated as a potential blood-based biomarker in prostate cancer. Furthermore this workflow could serve as a template to be used in other cancer entities.
- Subjects :
- 0301 basic medicine
Male
Databases, Factual
Prostatic Hyperplasia
urologic and male genital diseases
Proteomics
computer.software_genre
Exosomes
Biochemistry
Exosome
Mass Spectrometry
Analytical Chemistry
03 medical and health sciences
Prostate cancer
0302 clinical medicine
Cell Line, Tumor
medicine
Biomarkers, Tumor
Claudin-3
Humans
Claudin
Molecular Biology
Aged
Database
business.industry
Research
CLDN3
Cancer
Prostatic Neoplasms
Middle Aged
medicine.disease
3. Good health
Prostate-specific antigen
030104 developmental biology
030220 oncology & carcinogenesis
Biomarker (medicine)
Neoplasm Grading
business
computer
Subjects
Details
- ISSN :
- 15359484
- Volume :
- 16
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- Molecularcellular proteomics : MCP
- Accession number :
- edsair.doi.dedup.....08850d9a041849c767777524e4e0702f