RESUMO
Interaction between platelet and carcinoma cell contributes to pathogenesis of cancer-related thrombosis and metastasis. This study investigated whether physical exercise affects platelet-nasopharyngeal carcinoma cell (NPC) interaction and platelet-promoted tissue factor (TF) and matrix metalloproteinase (MMP) activities of NPC. Thirty sedentary men performed on three occasions moderate-intensity exercise [MIE, 60% maximal oxygen consumption (V(.)o(2max)) for 40 min] and high-intensity exercise (HIE, up to V(.)o(2max)), with and without warm-up exercise (WUE, 60% V(.)o(2max) for 20 min) on a bicycle ergometer. Before and immediately after exercise, platelet-NPC aggregation, the TF, MMP-2 and MMP-9 expressions and activities, and TF pathway inhibitor (TFPI) and tissue inhibitor of MMP-1 levels of NPC and platelet were measured. The results of this study demonstrated that HIE enhanced platelet-NPC aggregation in the presence of fibrinogen and was accompanied by increased platelet-promoted TF activity, expression of NPC, decreased platelet-promoted MMP-2 and MMP-9 activities, and TFPI release of NPC, whereas these alterations to HIE on platelet-NPC interactions were ameliorated by WUE pretreatment. Conversely, MIE reduced the formation of platelet-NPC aggregates, but did not change the TF, TFPI, MMP-2, MMP-9, tissue inhibitor of MMP activities, and/or levels of NPC mediated by platelet. It is concluded that HIE may enhance aggregation and coagulation and reduce MMP bioactivity related to platelet-NPC interactions, by raising the binding affinity to fibrinogen and TF activity and expression and lowering TFPI release and MMP-2 and -9 activities. These effects on HIE diminish after WUE. However, MIE minimizes the risk of thrombosis induced by platelet-NPC interactions.