Abstract Number: PB0746
Meeting: ISTH 2021 Congress
Background: Cancer cells are known to induce platelet aggregation in vitro in the presence of small amounts of plasma. Thrombin is considered to be the key platelet activator in this process. In several studies, it was shown that tumor-cell induced platelet aggregation (TCIPA) is not completely suppressed by integrin αIIbβ3 antagonists. Thus, the molecular mechanisms that underlie aggregate formation remain unclear and have been the focus of recent research.
Aims: The aim of this study is to investigate the mechanisms of platelet aggregation induced by cancer cells in vitro.
Methods: Human breast cancer cell line MCF-7 was maintained in DMEM. Washed human platelets (WP) were prepared by centrifugation from human citrated blood. Platelet aggregation was performed in a light transmission aggregometer Biola LA-220. Flow cytometry, electron and confocal fluorescence microscopy were utilized to characterize the aggregating suspension.
Results: Tumor cells induced washed platelet aggregation (TCIPA) in concentration of at least 104 cells/ml in presence of platelet-free plasma (PFP, 1%). Apyrase, monafram and aspirin had no effect on TCIPA, while hirudin prevented it completely. Prostaglandin E1 reduced maximum aggregation in a dose-dependent manner, but did not suppress it completely. No aggregation of PFA-fixed platelets was observed, while a 100% aggregation was observed for PFA-fixed platelets with fibrinogen at their surface. Flow cytometry, fluorescent and electron microscopy revealed normal platelet activation responses to happen during TCIPA. However, flow cytometry and confocal microscopy analyses did not reveal formation of heteroaggregates and direct cancer cell-platelet interaction.
Conclusions: We suggest that TCIPA in the presence of PFP starts with thrombin generation triggered by cancer cells. Although thrombin can induce platelet activation, this process is not necessary for the observed platelet aggregation.
The study was supported by Russian Science Foundation (grant 20-45-01014).
To cite this abstract in AMA style:Tesakov I, Filkova A, Deputatova A, Korneichuk A, Obydennyi S, Kireev I, Panteleev M, Sveshnikova A. Tumor Cell-induced Platelet Aggregation is Sustained by Platelet Entrapment into the Fibrin Network Formed by Thrombin [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/tumor-cell-induced-platelet-aggregation-is-sustained-by-platelet-entrapment-into-the-fibrin-network-formed-by-thrombin/. Accessed January 21, 2022.
« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/tumor-cell-induced-platelet-aggregation-is-sustained-by-platelet-entrapment-into-the-fibrin-network-formed-by-thrombin/