Development and Preliminary Clinical Application of Circulating Tumor Cell Detection System for Prostate Cancer

Real-time detection of circulating tumor cell (CTC) markers that are constantly changing and renewing during disease progression is of great significance for the timely regimen switch or individualized target therapy. The abnormally expressed special AT-rich sequence binding protein 1 (SATB1), a nuclear matrix attachment region binding protein, in various tumors, promotes the growth and metastasis of tumor cells by regulating gene expression. In this paper, a CTC detection system for prostate cancer (PCa) was developed on the basis of epithelial cell adhesion molecule (EpCAM)-targeted immunomagnetic separation and CK-FITC and SATB-1-APC immunofluorescence assay, and the recovery rate of tumor cells in PBS and simulated whole blood by this system was detected. Subsequently, we isolated, identified, and counted SATB-1 ositive CTCs in the peripheral blood and urine samples of 60 tumor-bearing nude mice, 5 healthy volunteers and 13 PCa patients. Combined with the clinicopathological factors, the clinical value of the system was analyzed, and the possibility of SATB-1-positive CTCs in the diagnosis of PCa was evaluated. The results showed that the CTC sorting and identification system for prostate cancer constructed in this study had a recovery rate of more than 85% for CTC in PBS, urine and blood simulation samples. The expression level of SATB-1 was different in different PCa cell lines, which was relatively high in the highly invasive PCa DU-145 cell line. The expression of SATB-1 in CTCs in the blood samples of PCa patients with different clinical characteristics and in the urine samples of a few PCa patients with bone metastases were different, and the detection sensitivity of peripheral blood was higher than that of urine. This study has important clinical reference value for the early diagnosis of PCa and the evaluation of bone metastasis based on the CTC counting and the SATB-1 expression in CTCs.