Figure 6.

pSV-Gap-MP probe allows convenient harvest of CTCs with the same high efficiency and specificity

(A) The design of pSV-Gap-MP. The key to this probe is the modified membrane form of GFP that is tagged with the HA tag (HA), which allows the CTCs to be easily pulled down by anti-HA IgG-conjugated magnetic nanoparticles. (B) Schematic illustration of pSV-Tag-MP-enabled pull-down of CTCs, by expressing the artificial chimeric protein (Tag-MP) on the surface of CTCs. (C) Differential distribution pattern of regular GFP and Tag-MP after expression in the human ovarian cancer cells (Hey). The top images show a micrographic field, and the bottom images show a magnified cell image from each of them. The regular GFP showed even or slightly higher nuclear distribution. In contrast, Tag-MP localizes predominantly on the cell membrane. (D) Pull-down of the spiked tumor cells incubated with pSV-Tag-MP but not pSV-GFP. The pulled-down tumor cells are indicated by the red arrows on the images at the top. The bottom image shows one of the pull-down cells 24 h later in higher magnification.