Abstract:Objective To investigate the killing effect of CCL25-PE38 immunotoxin on MOLT4 cell line in T-cell acute lymphoblastic leukemia (T-ALL) (CCR9 natural high-level expression), and to provide the foundation of targeting treatment of T-cell acute lymphoblastic leukemia (T-ALL). Methods Flow cytometryn and confocal microscopy were used to detect the binding and internalization of CCL25-PE38 and MOLT4 cells. Transwell chemotaxis chamber method was used to detect the chemotaxis. Cell Proliferation Reagent WST and Annexin V-FITC/PI stain were used to detect killing ability of cells and the apoptosis induced effect respectively. And antitumous effect of CCI25-PE38 was detected by building the SCID leukemia cells in mice xenograft tumor (CCR9+ tumors) model. Results WST-1 test showed that CCL25-PE38 produce specific lethal effect on MOLT4 cell. Annexin V-FITC/PI stain showed that the cause of death of MOLT4 cells was induced by apoptosis of CCL25-PE38. Injection of CCL25-PE38 in SCID leukemia cells in mice xenograft tumor (CCR9+ tumors) model can retard growth speed of CCR9+ cancer. Conclusions The cause of death of MOLT4 is induced by apoptosis-inducing effect of CCL25-PE38, which can retard the growth of CCR9+ xenotransplanted tumors.