Figure 1.

NPM-ALK–induced malignant transformation of normal human CD4⁺ T lymphocytes. A: Cell growth curves of NPM-ALK–expressing CD4⁺ T cells. Purified CD4⁺ T cells were stimulated with bead-immobilized CD3 and CD28 antibodies and either transduced with wild-type NPM-ALK (NA1) or enzymatically inactive NPM-ALK mutant (KD) or left untransfected. Triplicate cell cultures were counted using a cell counter. B: Cell growth curves of NPM-ALK–transfected CD4⁺ T cells (NA1, NA2, NA3) from three separate, consecutive experiments. C: Activation of ALK, STAT3, and mTORC1 pathways as determined by phosphorylation status of ALK, STAT3, and S6RP. Expression of total NPM-ALK and β-actin (ACTB) served as controls. ALK⁺ ALCL–derived cell line SUDHL-1, ALK-ALCL cell line 2B, and normal unstimulated CD4⁺ T cells were used as additional positive and negative controls. D: Migration of NPM-ALK–transfected cells determined using a Transwell culture system. Cells transfected with the enzymatically inactive NPM-ALK (KD) and untransfected cells (Ctrl) served as controls. P = 0.01 for NA1 and P = 0.04 for NA3 versus combined KD and Ctrl. E: Colony formation by the NPM-ALK–transfected NA1, NA2, NA3, and control ALK⁺ ALCL–derived SUDHL-1 cells. F: Cell volume of NPM-ALK–transfected and untransfected CD4⁺ T cells as determined by cell counter analysis (Beckman Coulter, Brea, CA). The ALK⁺ ALCL–derived cell line SUDHL-1 served as a positive control.