Background: The pathogenesis of the prothrombotic state in cancer is complex and may alter the efficiency of the antithrombotic agents but not all mechanisms are entirely understood.
Aims: In the present study we dissected the mechanisms responsible for the procoagulant activity of pancreas adenocarcinoma cells (BXPC3) and human breast carcinoma cells (MCF7) by thrombin generation assay (TG) in different relevant conditions, and we studied their influence on the antithrombotic efficiency of apixaban, fondaparinux and enoxaparin in a new experimental model.
Methods: Cells were cultured and adhered in 96-well plates and normal platelet poor or rich plasma (PPP; PRP) spiked or not with apixaban, fondaparinux or enoxaparin was added. TG was done with CAT® assay in different conditions of reagents, with or without any anti-tissue factor antibody (anti-TF), or corn trypsin inhibitor (CTI; inhibitor of the contact phase of coagulation). Alternatively spliced TF (asTF), TF activity (TFa) and cancer procoagulant (CP) were also assessed.
Results: The TFa and asTF were found in abundant amounts in BXCP3 than MCF7 cells. The CP levels were higher in MCF7. The BXPC3 amplified TG more than MCF7 did. The anti-TF inhibited TG triggered by BXCP3 and MCF7. The CTI had more pronounced inhibitory effect on TG triggered by MCF7. TG enhancement by BXPC3 and MCF7 was mediated by FVII. Factor XII was more important for TG enhancement by MCF7. Comparison on the basis of IC50 showed that in the presence of BXPC3 or MCF7 the efficiency of apixaban was preserved or partially reversed. Fondaparinux, was more vulnerable to the presence of cancer cells as compared to apixaban. The effect of BXCP3 or MCF7 cells on the antithrombotic potency of enoxaparin was of similar magnitude as that on apixaban.
Conclusion: The mechanism of activation of blood coagulation by the BXPC3 is dominated by the TF pathway, MCF7 additionally imply also FXII activation. The type of cancer cells is determinant for the antithrombotic efficiency of the specific factor Xa inhibitors. Modeling procoagulant profile of cancer cells provides an understanding of the procoagulant mechanisms and could evaluate the efficiency of antithrombotic treatment.