OBJECTIVETo explore the effects of anti-CD44 monoclonal antibody-IM7 on the in vitro adhesion and migration of chronic myeloid leukemia stem cell (CML-LSC) and its mechanism.

METHODSCD34(+)CD38(-)CD123(+) leukemic stem cells (LSC) from 20 newly-diagnosed chronic myeloid leukemia (CML) patients BM cells and CD34(+)CD38(-) hematopoietic stem cells (HSC) from 20 full-term newborn cord blood cells were isolated with EasySep(TM) magnet beads. The CD44 expression of the LSC and HSC was detected by flow cytometry (FCM), and the adhesion and migration ability of the LSC and HSC pre- and post-incubated with IM7 in vitro by MTT assay and transendothelial migration assay, respectively.

RESULTS(1) After incubated with IM7, the LSC and HSC CD44 expression rates were (86.60 ± 2.10)% vs. (25.40 ± 1.70)% (P < 0.05), respectively. (2) The adhesive ability of the LSC to endothelial cells was decreased markedly after incubated with IM7, the OD value (A(570)) changing from pre-incubation of (0.62 ± 0.11) to post-incubation of (0.34 ± 0.07), while there was little change of A(570) in the HSC group. (3) The migration ability of the LSC group was inhibited evidently after incubated with IM7, the inhibition rate being 46% ∼ 63%, while little change of that in HSC group was detected. (4) The adhesive ability of the LSC group to marrow stromal cells was decreased markedly after incubated with IM7, while little change was found in that of HSC group.

CONCLUSIONThe anti-CD44 monoclonal antibody-IM7 can effectively inhibit the adhesion and migration abilities of the LSC in vitro, which might provide a theoretical evidence for targeting therapy.