RESUMO
Cancer procoagulant is present only in malignant tumours and the undifferentiated tissues of human placenta. Its possible role in angiogenesis and metastasis was investigated. Cancer procoagulant increased the steady-state mRNA level of L1 cell adhesion molecule (L1CAM) in MCF-7 breast cancer cells and E14 mouse embryonic stem cells (MESCs), while an increase in angiogenin mRNA was observed in MDA-MB-231 breast cancer cells. Furthermore, production of vascular endothelial growth factor (VEGF) protein in MCF-7 breast cancer cells and E14 MESCs, but decreased in MDA-MB-231 breast cancer cells. We conclude that cancer procoagulant could potentially play a part in angiogenesis in cancer and vascular development during embryonic development.
Assuntos
Neoplasias da Mama/genética , Cisteína Endopeptidases/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação Neoplásica da Expressão Gênica , Proteínas de Neoplasias/metabolismo , Molécula L1 de Adesão de Célula Nervosa/genética , Células-Tronco/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Mama/citologia , Neoplasias da Mama/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Cisteína Endopeptidases/genética , Embrião de Mamíferos/citologia , Feminino , Humanos , Camundongos , Metástase Neoplásica/genética , Proteínas de Neoplasias/genética , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Fisiológica , Molécula L1 de Adesão de Célula Nervosa/metabolismo , RNA Mensageiro/genética , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Proteases are essential for tumour progression and many are over-expressed during this time. The main focus of research was the role of these proteases in degradation of the basement membrane and extracellular matrix (ECM), thereby enabling metastasis to occur. Cancer procoagulant (CP), a protease present in malignant tumours, but not normal tissue, is a known activator of coagulation factor X (FX). The present study investigated the function of CP in cancer progression by focussing on its enzymatic specificity. FX cleavage was confirmed using SDS-PAGE and MALDI-TOF MS and compared to the proteolytic action of CP on ECM proteins, including collagen type IV, laminin and fibronectin. Contrary to previous reports, CP cleaved FX at the conventional activation site (between Arg-52 and Ile-53). Additionally, degradation of FX by CP occurred at a much slower rate than degradation by conventional activators. Complete degradation of the heavy chain of FX was only visible after 24 h, while degradation by RVV was complete after 30 min, supporting postulations that the procoagulant function of CP may be of secondary importance to its role in cancer progression. Of the ECM proteins tested, only fibronectin was cleaved. The substrate specificity of CP was further investigated by screening synthetic peptide substrates using a novel direct CP assay. The results indicate that CP is not essential for either cancer-associated blood coagulation or the degradation of ECM proteins. Rather, they suggest that this protease may be required for the proteolytic activation of membrane receptors.