Expression pattern of androgen receptors, AR-V7 and AR-567es, in circulating tumor cells and paired plasma-derived extracellular vesicles in metastatic castration resistant prostate cancer

Abstract

Androgen-receptor splice variant 7 (AR-V7) is a highly promising liquid biopsy predictive biomarker showing primary or acquired resistance to novel androgen receptor signaling inhibitors in metastatic castration resistant prostate cancer (mCRPC).

Prognostic Significance of Gene Expression and DNA Methylation Markers in Circulating Tumor Cells and Paired Plasma Derived Exosomes in Metastatic Castration Resistant Prostate Cancer

“…Several groups including ours have verified the importance of using molecular assays for CTC molecular characterization [7,[16][17][18][19]23,26]. We have already shown that molecular assays based on real-time PCR carried out in nucleic acids material (RNA or genomic DNA) isolated from the EpCAM-positive CTC fraction can give valuable information for the molecular characterization of CTC at the gene expression, DNA methylation and DNA mutation level [4,16].…”

“…Capture beads, coated with the monoclonal antibody BerEP4 against the human epithelial antigen, EpCAM, were used for CTCs enrichment (Dynabeads ® Epithelial Enrich, Life Technologies, USA) as previously described [17,18]. Exosomes were isolated from 2mL of plasma by affinity-based binding to a spin column (exoRNeasy Maxi kit, QI-AGEN ® , Germany) as previously described [19]. Using this method, all exosomes were isolated.…”

“…The expression levels of TWIST1, ALDH1 and PD-L1 were normalized using the 2-ΔΔCt approach in respect to the expression of Β2Μ. We additionally used our recently developed multiplex RT-qPCR for the simultaneous quantification of AR-full length (AR-FL) and AR-V7, AR-567 splice variants using hydrolysis probes [19].…”

“…CTC enumeration in peripheral blood, based on the CellSearch ® system (Menarini, Italy), is still the only FDA-cleared assay for patients with metastatic prostate cancer [10] (10). The robust and semi-automated CellSearch platform enriches CTCs based on Ep-CAM expression and identifies these cells based on the absence of CD45 and the presence of cytokeratin (CK-8, CK-18, CK- 19) expression.…”

Prognostic significance of a combined gene expression analysis in EpCAM(+) CTCs in metastatic breast cancer based on a long follow-up

“…CTC analysis at the RNA level could provide important prognostic information and represents an innovative and promising approach in the clinical management of cancer patients (7,8). In metastatic castration resistant prostate cancer (mCRPC) there is now evidence showing that RNA analysis in CTCs at several time-points can demonstrate a continuous change in the expression of AR-V7 splice variant and this has already been connected with response to chemotherapy and androgen deprivation therapy (9)(10)(11).…”