Aptamer probed isolation of circulating tumor cells in cholangiocarcinoma patients

Abstract

Cholangiocarcinoma (CCA) is a typically lethal, highly metastatic cancer which poses diagnostic challenges and is consequently associated with poor prognosis and high metastatic capability. Since the currently used diagnostic biomarkers are limited in sensitivity and specificity, probes with high-affinity and good specificity are needed to study metastasis in CCA. Circulating tumor cells (CTCs) in blood have been widely accepted as an indicator of diseases progression and metastasis in various other cancers. We hereby report the first use of a CCA specific aptamer probe, coupled on magnetic beads for the isolation of CCA CTCs from 35 advanced stage/metastatic patients on an integrated microfluidic platform with 100 % efficiency ( > 1 CTC/mL were isolated). The isolated cells were identified via immunofluorescence staining (CK+ CD45(-) Hoechst(+)) and cell counting was assisted by ImageJ. The binding target of the aptamer on the CCA cancer cells was further analyzed and determined to be desmoplakin by liquid chromatography-mass spectrometry, western blotting, and immuno-fluorescence staining. It is envisioned that this biosensing platform could therefore be used for proactive CCA diagnostics in the near future.