Figure 7.

Effect of the combined action of nintedanib and MP07-66 on chronic lymphocytic leukemia cell survival. (A) Apoptosis of CLL cells from ten patients belonging to the various clinical and biological subtypes cultured in the absence and presence of 15 μM nintedanib, 8 μM MP07-66 or both over time analyzed by annexin V–propidium iodide flow cytometry. (B) Apoptosis of CLL cells from ten patients as described in (A) supplemented without or with 5 nM okadaic acid (OA) (right panels) for 6 h. Analysis by annexin V– propidium iodide flow cytometry is expressed as mean percentages of early and late apoptosis ± SD from three separate experiments performed in triplicate (*P≤0.01). (C) PP2A phosphatase activity performed on the total lysates of CLL cells treated as in (B). (D) Working model of the positive feedback signling loop triggered by the combination of nintedanib and MP07-66, which counters the high level of cytosolic tyrosine phosphorylation, the crucial factor sustaining the oncogenic machinery in CLL cells, mediated by the aberrant form of HSP90-bound Lyn.