STI571 treatment of P210^BCR-ABL 32D cells fails to decrease cell adhesion.

(A) P210^BCR-ABL 32D cells were incubated with (●) or without () 10 μM STI571 overnight prior to assaying adhesion. Typical profiles are shown and indicate that adhesion was not reduced, and may have slightly increased, as a result of tyrosine kinase attenuation by STI571. (–○–) represents a curve fitted to the experimental points. The critical shear stress (τ₅₀) is defined as the point on the abscissa (shear stress) that corresponds to an adherent fraction of 0.5 along the fitted curve. (B) The critical shear stress was calculated for a series of spins and is represented as the fold change in τ₅₀ relative to untreated P210^BCR-ABLcells. We tested 2 separate populations of P210^BCR-ABLcells (left, right) treated with (n = 5, n = 4), or without (n = 3, n = 4) 10 μM STI571 overnight (P = .008,P = .016). (C) pK1 control cells were incubated with (n = 4) or without (n = 10) 10 μM STI571 as in (B) (P = .06) and the data are represented as the fold change in τ₅₀ relative to untreated pK1 cells. Treatment of transduced 32D cells with STI571 did not affect nonspecific binding to BSA matrices (data not shown).