[Role of Ca2+-NFAT Signaling Pathway in Ph+ ALL Drug-resistance Mediated by Bone Marrow Stromal Cells]

Abstract

Objective: To explore the role of Ca²⁺-NFAT signaling pathway in Ph⁺-ALL drug resistance mediated by bone marrow stromal cells.

Methods: The transcription level of NFAT mRNA in Sup-B15 cells and Ph⁺ ALL primary cells was detected by polymerase chain reaction. The expression of P-glycoprotein in Sup-B15 cells was detected by flow cytometry. The change of NFAT protein in Sup-B15 cells was detected by Western blot. AnnexinV/7-AAD was used to label cells. Flow cytometry was used to detect cell apoptosis; Fluo 3-AM dye was used to label cells, and flow cytometry used to detect changes of Ca²⁺ concentration in leukemia cells.

Results: NFAT expression could be detected in both Sup-B15 and Ph⁺ ALL primary cells; P-glycoprotein could not be detected by flow cytometry; CAS could significantly inhibit NFAT protein expression in clinically applied drug concentrations (2.5, 5 μmol/L); Clinically applied concentration of CAS (2.5, 5 μmol / L) has no significant effect on the apoptosis of Sup-B15 cells, while higher concentration of CAS (10 μmol / L) could induce apoptosis of Sup-B15 cells. Bone marrow stromal cells OP9 could, decrease the sensitivity of Sup-B15 cells and Ph⁺ ALL primary cells to imatinib (IM); After co-culture with bone were marrow stromal cells, the Ca²⁺ concentration in Sup-B15 cells was enhanced, the levels of NFAT protein and nullear protein in sup-B15 cells also were enhanced. The addition of CAS in co-culture system could inlibit the Ca²⁺-NFAT signaling pathway, reduce the protective effect of OP9 on Sup-B15 cells.Conclution:The Ca²⁺-NFAT sigualing pathway, contributes to the survival of Ph⁺ ALL cells. Bone marrow stromal cells can mediate the resistance of Ph⁺ ALL cells to IM by activating Ca²⁺-NFAT signaling pathway.