title: Characterisation of platelet aggregation induced by PC-3 human prostate adenocarcinoma cells and inhibited by venom peptides, trigramin and rhodostomin.
abstract: PC-3 cells, a metastatic human prostate adenocarcinoma line, caused dose-dependent platelet aggregation in heparinised human platelet-rich plasma (PRP). PC-3 tumour cell-induced platelet aggregation (TCIPA) was completely inhibited by hirudin (5 U/ml) and limited by increasing concentrations of apyrase. This TCIPA was unaffected by cysteine proteinase inhibition with E-64 (10 microM), but was limited by cell pretreatment with phospholipase A2. PC-3 cell suspension caused marked, dose-dependent decreases in plasma recalcification times using normal, Factor VIII-deficient and Factor IX-deficient, but not Factor VII-deficient, human plasma. This effect was potentiated in cell lysates, but was inhibited in intact cells preincubated with sphingosine. Overall, these data suggest that PC-3 TCIPA arises from PC-3 tissue factor activity expression. Trigramin and rhodostomin, RGD-containing snake venom peptides which antagonise the binding of fibrinogen to platelet membrane glycoprotein IIb-IIIa, prevented PC-3 TCIPA. Similarly, synthetic peptide GRGDS as well as monoclonal antibodies against platelet membrane glycoproteins IIb-IIIa and Ib prevented PC-3 TCIPA, which was unaffected by control peptide GRGDS. On a molar basis, trigramin (IC50, 0.11 microM) and rhodostomin (IC50, 0.03 microM) were approximately 5000 and 18000 times, respectively, more potent than GRGDS (IC50, 0.56 mM).
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Swaim
authors.forename: H S
authors.initials: HS
authors.lastname: Chiang
authors.forename: T F
authors.initials: TF
authors.lastname: Huang
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000473:pathology*; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001081:Apyrase / Q000494:pharmacology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D005340:Fibrinogen / Q000037:antagonists & inhibitors; D006023:Glycoproteins / Q000276:immunology; D006629:Hirudins / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D010455:Peptides / Q000494:pharmacology; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000473:pathology*; D013917:Thrombin / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D015853:Cysteine Proteinase Inhibitors; D006023:Glycoproteins; D006629:Hirudins; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; C054194:trigramin; C072026:rhodostomin; D005340:Fibrinogen; D010741:Phospholipases A; D054467:Phospholipases A2; D013917:Thrombin; D001081:Apyrase