Research Paper Volume 12, Issue 6 pp 5091—5120

Time-dependent interactions of blood platelets and cancer cells, accompanied by extramedullary hematopoiesis, lead to increased platelet activation and reactivity in a mouse orthotopic model of breast cancer – implications for pulmonary and liver metastasis

Figure 6. Time-course of circulating platelet activation in mice injected with 4T1 cancer cells during 5-week breast cancer development. Results are presented as median (horizontal line) and interquartile range (box) (n = 8). The expressions of P-selectin (CD62P) (A), the active form of GPIIb/IIIa (B) and the binding of endogenous vWF (C) and endogenous fibrinogen (Fg) (D) on resting platelets were measured using flow cytometry in non-fixed ‘washed blood’ withdraw immediately (t0, open boxes) or after 2 (t2, light grey boxes), 3 (t3, grey boxes), 4 (t4, dark grey boxes) or 5 weeks (t5, black boxes) from the injection of 4T1-cells. Results are expressed as the percent fraction of platelets positive for a given activation marker. More experimental details are given in the Materials and methods section. The statistical significance of differences, estimated with Kruskal-Wallis test followed by post hoc all-pairwise comparisons Conover-Inman or one-way ANOVA followed by Tukey’s multiple comparisons test, was: P-selectinresting, P1,α < 0.05, 4T1 t5 > 4T1 t4 > 4T1 t3 > 4T1 t2 > 4T1 t0; active form of GPIIb/IIIaresting, P1,α < 0.01, 4T1 t5 > 4T1 t4, 4T1 t3, 4T1 t2, 4T1 t0; 4T1 t4 > 4T1 t2, 4T1 t0; vWFresting, P1,α < 0.05, 4T1 t5 > 4T1 t4 = 4T1 t3 = 4T1 t2 > 4T1 t0; Fgresting, P1,α < 0.01, 4T1 t5 > 4T1 t2, 4T1 t0; 4T1 t4 > 4T1 t2, 4T1 t0.