Detection of circulating tumor cells by recombinant virus

Abstract

The detection and molecular characterization of circulating tumor cells(CTCs) is one of the most important tool for liquid biopsy, which has the potential to enable non-invasive diagnostic tests for personalized medicine. Commercial platforms represented by CellSearch, the first FDA approved assay, have been considered to be valid for CTCs detection. However, special equipment and consumptive materials are required in the techniques listed above. Besides, most of them can not differentiate between apoptotic and viable cells, which indicates the portion of active and functional CTCs. Therefore, how to develop novel method for CTCs enrichment with metastatic potential has great significance in clinical routine. Telomerase-specific replication-selective oncolytic viruses expressing green fluorescent protein(GFP), including herpes simplex virus and adenovirus, allow the detection for human CTCs in the peripheral blood. After 24 h of transfection with recombinant virus, the tumor cells stably express GFP, and it could be used for CTCs counting by fluorescent microscopy or flow cytometry. Moreover, downstream analysis would be achieved by combination with PCR or DNA sequencing. Recombinant virus enables early detection of metastatic tumor cells, because the fluorescent signal is amplified only in viable, infected CTCs, by viral replication. This GFP-expressing virus-based method is remarkably sensitive, simple, and feasible, and it offers a new opportunity to detect and characterize CTCs in clinical routine. Key words: Circulating tumor cells; Herpes simplex virus; Adenovirus; Green fluorescent protein; Telomerase