FIGURE 4.

Inhibition of GPIIb/IIIa on platelets and ανβ3 on melanoma cells inhibits platelet-melanoma cell interaction under flow conditions. A–C, firm adhesion of CMFDA-labeled B16 cells (2 × 10⁵/ml) on a monolayer of b.END.3 cells preincubated with freshly isolated murine platelets (PLT, 1 × 10⁸/ml) or Tyrode's buffer (ctrl.) was assessed at shear rates of 500 s⁻¹ at the indicated time points. A, B16 cells were exposed to RGD peptide or RAD control peptide (10 μg/ml) prior to the assay. Data are representative of four experiments with similar results (means ± S.D.). *, p < 0.05. B and C, similarly, adhesion of B16 cells to bEND.3 cells was assessed in the presence (PLT) or absence (ctrl.) of freshly isolated murine platelets after preincubation of platelets with blocking anti-CD61 (β3 integrin) mAb (10 μg/ml; or hamster IgG isotype control) (B), as well as preincubation of B16 cells with anti-CD51 (αν integrin) mAb (10 μg/ml; or rat IgG1 isotype control) (C). Data are representative of four experiments with similar results (means ± S.D.). *, p < 0.05.