PTPROt overexpression inhibits cellular proliferation and induces apoptosis. (A) Cellular proliferation of tet-inducible PTPROt clones. Tet-inducible FLAG-tagged WT, CS, or DA PTPROt clones were cultured with or without Dox for 1 to 4 days (x-axis) and analyzed in MTT proliferation assays. Proliferation on days 2 to 4 is represented as fold increases compared with the initial day-1 measurement (y-axis). (B) Apoptosis of tet-inducible PTPROt clones. Tet-inducible FLAG-tagged WT, CS, or DA PTPROt clones were cultured with or without Dox for 4 days and analyzed thereafter with annexin V–FITC/PI staining. (x- and y-axes, respectively). The percentages of cells staining with PI alone (G1), annexin V and PI (G2), annexin V alone (G4), or neither reagent (G3) are indicated.