The heterogeneity and clinical relevance of circulating tumor-initiating cells in hepatocellular carcinoma using an integrated immunomagnetic-microfluidic platform.

Abstract

e15132 Background: Circulating tumor-initiating cells (CTICs) with stem cell-like properties play important roles in tumor metastasis and recurrence. Little is known about CTICs biology and their clinical relevance. By using a novel integrated immunomagnetic-microfluidic platform, we investigated CTICs heterogeneity, molecular feature and clinical relevance in HCC. Methods: The CTICs detection platform was constructed and cell capture efficiency was evaluated using spiked cell experiments and was further compared with CellSearch system. We applied a four-channel microfluidic chip to investigate the composition of CTICs via simultaneous detection of 4 CTICs subsets (EpCAM+, CD133+, CD90+ and CD24+) in 14 primary HCCs and 13 recurrent HCCs. The dynamic changes of 4 CTICs subsets were serially monitored in 5 HCC patients. The retrieved CTICs were subjected to single-cell RNA profile. Results: A paired comparison in 25 HCC patients indicated that the number of EpCAM+ CTICs detected by microfluidic platform was significantly higher compared with CellSearch system (0.66±0.70 vs. 0.19±0.29, P=0.038). EpCAM+ CTICs ≥0.75/ml detected by the platform was a significant predictor of early recurrence (P<0.001). The median proportion of EpCAM, CD133, CD90 and CD24 subsets was 66.67%, 9.06%, 0%, and 0% in primary HCC and 0%, 0%, 52.27% and 9.09% in recurrent HCC, respectively. Serial CTICs monitoring in 5 patients suggested that the HCC recurrence was associated with an increase in CD90+ CTICs. Remarkably, acquired resistance to transcatheter arterial chemoembolization chemotherapy was accompanies by increasing proportion of CD24+ CTICs (0% to 75%). Single-cell transcriptional profiling showed heterogeneity among individual CTICs, separating 4 CTIC subsets into two distinct populations: EpCAM+ and CD24+ cells with epithelial phenotype, CD133+ cells and CD90+ cells with mesenchymal feature. Conclusions: CTICs heterogeneity was existed during tumor progression. The platform represents a novel and informative tool for accurate CTICs detection and characterization, enabling in-depth cancer biology research and clinical cancer management.