RESUMO
<p><b>OBJECTIVE</b>To explore the effect of platelets on signal transducers and the sensitivity of leukemia cells to chemotherapeuticl drugs in leukemia cells L1210.</p><p><b>METHODS</b>Murine platelets were prepared and cocultured with leukemia L1210 cells, and the aggregation between them was observed by flow cytometry. The levels of several transducer proteins in leukemia cells were analyzed with Western blot. In some experiments, methotrexate, vincristine or doxorubicin was added to the coculture system and the cell proliferation was measured by using CCK8 colorigenic methods to detect the sensitivity of leukemia cells to the therapeuticals drugs.</p><p><b>RESULTS</b>Platelets, either freshly prepared or fixed with 1% paraformaldehyde, aggregated with leukemia cells. Both fresh and fixed platelets increased the level of phosphorylation of AKT and ERK in leukemia cells as measured with Western blot. Also, platelets significantly decreased the sensitivity of 3 therapeutics to L1210 cells.</p><p><b>CONCLUSION</b>Platelets may bind with L1210 cells and decrease the sensitivity of the leukemia cells to chemotherapeutics, possibly by activating the AKT and ERK signaling pathways.</p>