Figure 9.

Specific silencing of BTK full-length or BTK^p52 reduces PLCγ1 phosphorylation and autonomous Ca2⁺ oscillations in BCR-ABL ⁺ pre–B lymphoblastic leukemia cells. BCR-ABL1 ⁺ pre–B lymphoblastic leukemia cells were transfected with nontargeting siRNAs or siRNAs against full-length BTK, BTK^p52, or BTK^p65, then subjected to intracellular staining for tyrosine-phosphorylated PLCγ1 and analyzed by flow-cytometry (A). Cytoplasmic Ca²⁺ levels [nmol/l] were measured in single siRNA-containing cells by confocal laser-scanning microscopy by continuous scanning for 6 min (B). Before analysis of Ca²⁺ levels, leukemia cells carrying fluorescein-labeled siRNAs were sorted by FACS. For each condition, ∼50 individual cells were recorded. As a control, cytoplasmic Ca²⁺ levels were measured in cells with nontargeting siRNAs (red line).