Figure 1. The administration of low-dose aspirin constrains enhanced metastatic potential of mesenchymal-like cancer cells induced by platelets.

A. and B. HT29 cells (1×10⁶) were cultured alone (HT29) or cocultured with platelets (1×10⁸) (HT29-PLT) for 40h; after the incubation, HT29 cells were extensively washed with PBS to remove platelets, harvested with trypsin, resuspended in HBSS (at a concentration of 5×10⁶ cells/mL); 200 μL of cell suspension (corresponding to 1×10⁶ cells) were injected into the lateral tail vein of NSG mice (n=5 each group). In HT29-PLT-ASA group (n=5), mice were treated with aspirin (20 mg/kg, p.o., once a day) starting from 4 days before the injection of HT29 cells cocultured with platelets and up to 7 days after the injection of the cells; one week from the injection, mice were sacrificed, lungs were collected, formalin-fixed and submitted for histopathology and the hematoxylin-eosin (H&E) stained microscopic sections were analyzed for metastatic score (obtained by combining the size of detected lesions × the surface area involved); mean ± SEM (n=5), *P<0.05 vs HT29 and ^§P<0.05 vs HT29-PLT. C. and D. Twenty four-h urine samples were collected to assess the urinary excretion of TX-M and PGE-M; mean ± SEM (n=5), *P<0.05 vs HT29, §P<0.01 vs baseline. **P<0.01 vs HT29-PLT, #P<0.05 vs all the other conditions. E. H&E stain showing fibrin and red blood cells in lung sections. (*) In the bottom panel a thrombus containing aggregates of neoplastic cells is shown. Original magnification 20x and 40x.