Figure 3. In vitro activity of increasing concentrations of various tyrosine kinase inhibitors on calcium levels induced by InsP3 in K562 or CML-PBM cells. 10⁶ cells were incubated with 5 µM InsP3 alone or with increasing concentrations (0–50 µM) of IM, PP1, or LY (KRH medium, calcium-free). (A) Represents the effect of 7.5 µM IM alone or in association with equimolecular doses of PP1 or LY in K562 cells. (B) Represents the effect of 6.9 µM IM alone or in association with equimolecular doses of PP1 or LY in CML-PBM cells. Data represent the [Ca²⁺]_i values (mean ± SD) obtained in 4 distinct experiments performed in duplicate. (*P < 0.05 vs. InsP3 alone; ** P < 0.05 vs. IM alone).