Biological Characteristics Of CD133-2in Childhood B-lineage Acute Lymphoblastic Leukemia And Its Primary Molecular Mechanism

Objective To explore the significance of expression of CD133-2in childhoodB-lineage acute lymphoblastic leukemia (B-ALL) and its primary molecular mechanism,we evaluated whether CD133-2will be a marker of leukemia stem cells (LSC), and whichmechanism in pathogenesis it is in childhood B-ALL.Methods1) Expressions of CD133-2was detected by flow cytometry in newlydiagnosed38children with B-ALL.2) CD133-2+CD19+、 CD133-2+CD19-、CD133-2-CD19+and CD133-2-CD19-subgroup cells in5cases were sorted by MagneticActivated Cell Sorting (MACS). They were cultured respectively in methylcellulosesemi-solid medium (including FBS, SCF, GM-CSF, G-CSF, IL-3, IL-6and EPO). Theability of colony forming was analysed and cells’ morphology were evaluated byWright-Giemsa.3) The key molecules of TGF-β signaling pathway were tested forCD133-2+CD19-cells and CD133-2-CD19+subgroups by gene microarray kit and real-timequantitative PCR array.Results1) The rate of expression of CD133-2was60.5%. CD133-2+CD19-subgroup can differentiate into erythroid burst forming unit (BFU-E) on day5and othermixed colony [including erythroid colony formation unit (CFU-E), granulocyteCFU(CFU-G), macrophage CFU(CFU-M), CFU-GM] on day7. The colony numbers ofCD133-2+CD19-subgroup were proliferated to initial tenfold, but they cannot be foundexpansion after day14. After the colony cells of CD133-2+CD19-subgroup were tested formorphology by Wright-Giemsa, they were found to include erythrocytes, granulocytes andmacrophages. Other three subgroups didn’t form colony (P<0.001).2) Compared to the CD133-2-CD19+, formation of CD133-2+CD19-subgroup inpatients with B-ALL at diagnosis was related with upregulation of DCN, IGFBP3, THBS1, Smad6and downregulation of SERPINE1. It was related to upregulation of TGFβ1,LTBP1and downregulation of IGFBP3, SERPINE1in relapsed cases.Conclusions1) In vitro, CD133-2+CD19-cells owned the ability of differentiationinto multiple-lineage in childhood B-ALL, therefore they possess the characteristics ofLSC.2) DCN, IGFBP3, THBS1, Smad6and SERPINE1maybe play an important role inB-ALL at diagnosis. And TGFβ1, LTBP1，IGFBP3and SERPINE1may take effect inrecurrent cases.