At 2-week intervals the cells were tested on the CAM for metastatic ability and assayed for expression of urokinase-type plasminogen activator (uPA) and the M(r) 92,000 and M(r) 72,000 gelatinase/type IV collagenases, enzymes the expression of which has previously been shown to correlate with tumor cell dissemination.
Together with previous findings of urokinase-type plasminogen activator and its mRNA being located in fibroblast-like cells in the tumor stroma and mRNA for the urokinase receptor in the cancer cells at invasive foci, these results indicate a complex cooperativity among several cell types in regulation of plasminogen activation in colon cancer.
The modest increase in uPA receptor expression may lead to a normalization of uPA antigen content in RCC; however, it is not sufficient to substantially increase tumor tissue-uPA content over the level of normal non-tumorous kidney tissue.
Urokinase-type plasminogen activator (uPA) is a serine proteinase that has been implicated in the pathogenesis of several epithelial tumors, but its role in HPV-associated tumors is not known.
Immunocytochemical staining for uPA showed strong immunoreactivity in the tumor cells and vasculature of glioblastomas and anaplastic astrocytomas but undetectable or very low immunoreactivity for uPA in low-grade gliomas and normal brain tissues. uPA mRNA was located in astrocytoma and endothelial cells and was heterogeneously distributed within glioblastoma, with preferential localization near vascular proliferation and at the leading edge of the tumor. uPA expression was dramatically higher in highly malignant astrocytomas, especially glioblastomas, and was correlated with malignant progression of astrocytomas.
Northern analysis showed the presence of both human and mouse urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor mRNA in tumor extracts.
Patients with uPA-positive/E-cadherin-negative expression had the poorest prognoses, compared with the three other groups of patients uPA-positive/E-cadherin-negative tumors had a fourfold relative risk of death when compared with uPA-negative/E-cadherin-positive tumors.
We have compared by RNA in situ hybridisation on serial cryo-sections the distribution of cathepsin D (cathD), stromelysin 3 (strom-3), and urokinase plasminogen activator (UPA) gene expression in different tissues of human benign and malignant mammary tumors.
The results presented demonstrate the usefulness of pAb HU277 in locating uPA-R in tumor and normal cells with high sensitivity in formalin-fixed, paraffin-embedded breast tissue.
The altered expression of u-PA, u-PAR and PAI-1 in diploid and aneuploid prostate cancer suggests a possible role of fibrinolytic proteins in the different biologic behavior of tumors, and may be one explanation for the higher metastatic potential of aneuploid tumors.
In contrast, the intensity of uPA staining provided significant prognostic information in that patients with strongly uPA-positive tumors had a poorer outcome than patients with weakly uPA-positive or uPA-negative tumors.
Since alteration of the DNA methylation status of CpG island in the 5' sequence of oncogenes and tumor suppressor genes has been demonstrated to change their expression, we examined DNA methylation as a potential molecular mechanism for regulating uPA gene transcription in these cancer cells.
The urokinase-type plasminogen activator (uPA) and uPA receptor (UPAR) play important roles in the proteolytic cascade involved in the invasiveness of gliomas and other invasive tumors.
Intrinsic differences in the tumor cells such as the production of u-PA antigen and u-PA receptor on the cell surface and extrinsic differences in the tumor cell environment such as substances influencing u-PAR display or antibodies blocking the u-PAR may affect the biological potential of human bladder cancers and offer one explanation for the aggressive or indolent tumor behavior observed in individual patients.
To assess the participation of the plasminogen activation system in the invasiveness of esophageal squamous cell carcinoma, we performed immunohistochemistry and in situ hybridization to study the distribution of a urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR), and plasminogen activator inhibitor-2 (PAI-2). u-PA and PAI-2 were expressed heterogeneously in cancer cells, and restricted expression was found in stromal cells, especially fibroblasts, that were located in the immediate proximity of the cancerous cells. u-PAR was found only in cancer cells located at the periphery of tumors.