Affiliation:
1. Analysis of Circulating Tumor Cells Lab, Department of Chemistry, University of Athens, Athens, Greece
2. Institute for Cell Biology, Histology and Embryology, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
3. Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
4. Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
5. University Institute for Clinical Research (IURC), Laboratory of Rare Human Circulating Cells, University Medical Centre of Montpellier Saint-Eloi Hospital, EA2415, Montpellier, France
Abstract
Abstract
BACKGROUND
Molecular characterization of circulating tumor cells (CTCs) is important for selecting patients for targeted treatments. We present, for the first time, results on gene expression profiling of CTCs isolated in vivo from high-risk prostate cancer (PCa) patients compared with CTC detected by 3 protein-based assays—CellSearch®, PSA-EPISPOT, and immunofluorescence of CellCollector® in vivo-captured CTCs—using the same blood draw.
METHODS
EpCAM-positive CTCs were isolated in vivo using the CellCollector from 108 high-risk PCa patients and 36 healthy volunteers. For 27 patients, samples were available before and after treatment. We developed highly sensitive multiplex RT-qPCR assays for 14 genes (KRT19, EpCAM, CDH1, HMBS, PSCA, ALDH1A1, PROM1, HPRT1, TWIST1, VIM, CDH2, B2M, PLS3, and PSA), including epithelial markers, stem cell markers, and epithelial-to-mesenchymal-transition (EMT) markers.
RESULTS
We observed high heterogeneity in gene expression in the captured CTCs for each patient. At least 1 marker was detected in 74 of 105 patients (70.5%), 2 markers in 45 of 105 (40.9%), and 3 markers in 16 of 105 (15.2%). Epithelial markers were detected in 31 of 105 (29.5%) patients, EMT markers in 46 of 105 (43.8%), and stem cell markers in 15 of 105 (14.3%) patients. EMT-marker positivity was very low before therapy (2 of 27, 7.4%), but it increased after therapy (17 of 27, 63.0%), whereas epithelial markers tended to decrease after therapy (2 of 27, 7.4%) compared with before therapy (13 of 27, 48.1%). At least 2 markers were expressed in 40.9% of patients, whereas the positivity was 19.6% for CellSearch, 38.1% for EPISPOT, and 43.8% for CellCollector-based IF-staining.
CONCLUSIONS
The combination of in vivo CTC isolation with downstream RNA analysis is highly promising as a high-throughput, specific, and ultrasensitive approach for multiplex liquid biopsy-based molecular diagnostics.
Funder
European Regional Development Fund
Austrian Science Fund
Publisher
Oxford University Press (OUP)
Subject
Biochemistry, medical,Clinical Biochemistry