Apoptosis of leukemia cells induced by CD34+ cells transferred exogenous Fas ligand.

To assess the value of CD34+ cells transferred exogenous Fas ligand (FasL) in inducing apoptosis of human leukemic cells, the CD34+ cells transfected with FasL or without, pretreated with mitomycin C, was mixed with leukemic cell line U937 cells in presence or absence of daunorubicin (DNR) or cytosine arabinoside (Ara-C). After 18 h, apoptosis of cells was detected by FCM and TUNEL. Induced for 18 h by CD34+ cells transfected with FasL or without, the ratio of apoptosis of U937 cells was (5.0 +/- 1.3)%, (10.8 +/- 0.6)% (P < 0.01), respectively. Induced by FasL+ CD34+ + DNR, FasL+ CD34+ + Ara-C, the ratio was (13.4 +/- 1.0)% (P < 0.05), (17.9 +/- 1.3)% (P < 0.01), respectively. The result demonstrated that CD34+ cells transfected with exogenous FasL could induce apoptosis of human leukemic cells and showed a cytotoxic synergistic effect when used in combination with chemotherapeutic drugs, suggesting that it was possible to develop a new method in treatment of leukemia.