Tumor cell induced platelet aggregation (TCIPA) played an importance role in early state of
thrombosis in
cancer patients. In addition, TCIPA was recognized as one important step in metastatic cascade.
Cholangiocarcinoma, one of the most common
cancers in the north-eastern part of Thailand, associated with
thrombosis was reported. The authors investigated the effects of
cholangiocarcinoma cells on platelet function as measured by platelet aggregation. Primary human
cholangiocarcinoma (HuCCA) cells were established in our laboratory. Cells were cultured as standard techniques and grown to confluence until used, after which cells were replaced with fresh medium (Dulbeco Modified Eargle's Medium, DMEM) without serum for 24, 48 and 72 h. Then, the
conditioned medium (CM) was collected. CM (24, 48 and 72 h) from HuCCA failed to induce platelet aggregation, whereas, HuCCA pellets induced platelet aggregation and potentiated platelet aggregation induced by submaximal concentration of
thrombin. Interestingly, platelet aggregation induced by HuCCA was inhibited by
hirudin (
thrombin receptor antagonist; 10, 20 and 40 U) in a dose dependent manner. Thus,
cholangiocarcinoma cells can induce platelet aggregation in a direct
tumor cell-platelet contact via
thrombin receptor. Therefore, the use of
antiplatelet agents especially via
thrombin receptors may help to prevent TCIPA or
metastasis by CCA.