Thromboxane production by platelets during tumor cell-induced platelet activation.
Invasion Metastasis
; 11(2): 102-9, 1991.
Article
em En
| MEDLINE
| ID: mdl-1917383
We have evaluated in a homologous system the mechanisms of platelet activation by cells isolated from fresh human tumor tissues and the role of thromboxane B2 (TxB2) generation in this process. Thirty-eight of the 46 tumor tissues considered showed a high platelet-aggregating activity, with no particular distribution in any specific tumor type. Apyrase caused a nonsignificant reduction in the aggregation response, hirudin did not change it, while iodoacetic acid or p-hydroxymercuriphenylsulfonate, specific cysteine proteinase inhibitors, significantly reduced the platelet-aggregating capacity of these tumor cells. In 9 colon carcinomas and in 8 breast carcinomas the levels of TxB2 produced by platelets after addition of tumor cells were measured: tumor cell-induced platelet aggregation was accompanied by a significant production of the metabolite; indobufen, a cyclooxygenase inhibitor, significantly reduced aggregation and particularly TxB2 production, while the drug had no effect on both parameters if preincubated with tumor cells only. These data suggest that cells isolated from different human tumor tissues activate platelets through the activity of tumor-associated cysteine proteinase(s); platelet aggregation by tumor cells is largely dependent on arachidonic acid metabolism in platelets, while such metabolism in tumor cells does not play a significant role.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tromboxano B2
/
Plaquetas
/
Ativação Plaquetária
/
Agregação Plaquetária
/
Neoplasias
Limite:
Adult
/
Humans
Idioma:
En
Revista:
Invasion Metastasis
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Itália