Expression of P210^BCR-ABL increases adhesion to fibronectin compared to control pK1 cells.

(A) Fraction of adherent cells after a 10-minute spin is plotted versus surface shear stress, τ, for P210^BCR-ABL() or pK1 control cells (●). A higher proportion of P210^BCR-ABLcells remain attached at nearly every given shear stress compared to pK1 cells suggesting that P210^BCR-ABL leads to increased binding to fibronectin. (–○–) represents a curve fitted to the experimental points for P210^BCR-ABL or vector control pK1. The dashed line represents an adherent fraction of 0.5. 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) τ₅₀ was determined for spins with cells expressing P210^BCR-ABL (n = 5) or pK1 control (n = 12), indicating that an average of 1.7 times as much force is needed to detach 50% of P210^BCR-ABL–expressing cells from fibronectin compared to pK1 cells (P < .001). Nonspecific binding between P210^BCR-ABL 32D cells to BSA matrices was minimal and similar to pK1 32D control cells (data not shown).