TC-PTP expression is required for tumor maintenance in vivo. (A) TC-PTP knockdown tumors are not maintained in vivo. DBL-114 cells were transduced with either a control shRNA (shLuc) or an shRNA specific to TC-PTP (shTC-PTP.2). Transduced cells were then sorted to > 95% GFP+ (infected), and 105 of these cells were adoptively transferred into cohorts of age- and sex-matched C57BL6 mice. These mice were allowed to develop externally palpable tumors, at which point they were killed and their tumors examined for cell numbers and GFP fluorescence. Tumorous spleens were harvested, and single-cell suspensions were generated and then enumerated. Wild-type spleen counts are shown for comparison. (B). Tumors that do develop in mice injected with TC-PTP knockdown tumor cells are GFP−. Tumors were harvested from mice injected with either shLuc or shTC-PTP.2 tumor cells and subjected to FACS analysis to determine the frequency of GFP+ cells.
