Assessment of cross-talk between Notch and BCR-ABL activity in CD34+ primary CML cells.

<p><b>(a)</b><i>Hes1</i> gene expression in CD34+ cells isolated from GSI-responder CML patients. CD34+ cells were isolated from CML patients and cultured in the presence of 10 μM GSI for 72h. Live CD34+ cells were then sorted, and the gene expression of the Notch target gene <i>Hes1</i> was investigated by real-time PCR (*<i>p<0</i>.<i>01</i>). <b>(b)</b><i>Hes1</i> gene expression in CD34+ cells isolated from GSI-nonresponder CML patients. <b>(c)</b> Overexpression of P-crkl in CD34+ CML cells treated with GSI. CD34+ cells from five CML patients in chronic phase were cultured in the presence of 10 μM GSI. The change in BCR-ABL activity was assessed by the FACS-based P-crkl assay. <b>(d)</b> P-crkl expression was measured by mean fluorescence intensity (MFI) units in each condition. MFI of P-crkl in GSI-treated CD34+ cells were compared to a no-drug control in each sample, and the percentage of increase in P-crkl was calculated. Data shown here represent the mean of six CML samples (**<i>p<0</i>.<i>01</i>).