Figure 1.

In vitro effect of nintedanib on the differently phosphorylated forms of SHP-1 pulled down from chronic lymphocytic leukemia cells. (A) Phosphorylation state of SHP-1 in total cell lysates, particulate and cytosol of CLL cells of patients belonging to various clinical and biological subtypes. Anti-LDH (cytosolic marker), anti-PMCA (plasma membrane marker). (B) Tyrosine phosphatase activity of SHP-1 immunoprecipitated from particulate and cytosol of CLL of patients #2, #17, and #36 measured as [³²P] released from in vitro [³²P]-Band 3. (C) Tyrosine phosphatase activity of SHP-1 immunoprecipitated in the absence (Ip1-SHP-1) and presence (Ip2-SHP-1) of serine/threonine phosphatase inhibitors from the cytosol of CLL cells of 15 patients as determined in vitro in the presence of increasing concentrations of nintedanib supplemented without (solid circles) or with 25 μM PTP I-I (open circles). Data are mean ± SD of three experiments performed in triplicate (*P≤0.01). LDH: lactate dehydrogenase; PMCA: plasma membrane Ca2⁺ ATPase; Wb: western blot; IP: immunoprecipitation.