Fibrinolytic activity of in vitro cultivated human bladder cell lines

Immunohistochemical expressions of uPA and its receptor uPAR and their prognostic significant in urinary bladder carcinoma

BACKGROUND

The authors found previously that plasma levels of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) were elevated in patients with bladder carcinoma and were associated with features of biologically aggressive disease. The present study has been performed to analyze the expressions of two antigens by immunohistochemical staining in bladder transitional cell carcinoma.

PATIENTS AND METHODS

The tumors from 72 men and 28 women with a mean age 46.15 years (range 30-67 years) were examined. Paraffin sections of 5 microm thickness were prepared for immunohistochemical staining of uPA and uPAR antigens. Age, sex, tumor grade and stage, DNA ploidy, lymph node status, and metastases were evaluated in relation to outcome. Univariate and multivariate analysis of survival were performed.

RESULTS

The overall 5-year survival was 66%. Thirty six and 46 cases were positive for uPA and uPAR expressions, respectively. In univariate analysis, tumor stage, lymph node status, metastases, uPA and uPAR have a significant impact on the survival for these patients. In a Cox proportional hazard model, uPAR sustained its significant impact on survival.

CONCLUSIONS

These findings suggest that uPAR is an independent additional prognostic factor in patients with transitional cell carcinoma of the bladder.

Urokinase and the urokinase receptor: association with in vitro invasiveness of human bladder cancer cell lines

BACKGROUND AND PURPOSE

The plasminogen activators urokinase and tissue plasminogen activator are enzymes that degrade proteins in tissue basement membranes and the extracellular matrix (a biomolecular complex surrounding individual cells in tissues that serves as a barrier between the cells and the vascular and lymph systems). The action of these enzymes allows tumor cells to escape their local environment and metastasize. Plasminogen activator activity can be influenced by the urokinase receptor, which is expressed on the surface of cells, and by the plasminogen activator inhibitors 1 and 2. Because bladder tumors differ in their propensity to invade local areas and distant sites, we studied the expression of both plasminogen activators, the two plasminogen activator inhibitors, and the urokinase receptor in four human bladder cancer cell lines (RT4, 253J, EJ, and T24) to see if there was an association between the expression of these proteins and tumor cell invasiveness in vitro.

METHODS

The expression of urokinase, tissue plasminogen activator, and the two inhibitors was measured by enzyme-linked immunosorbent assays of serum-free, cell-conditioned media (i.e., culture fluids). Cell surface expression of the urokinase receptor was assayed by flow cytometry, using an anti-receptor monoclonal antibody (Mab3936). The invasive capacity of untreated cells and of cells exposed to exogenous, high-molecular-weight urokinase was analyzed by use of Matrigel invasion chambers.

RESULTS

The four bladder cancer cell lines demonstrated differential expression of both plasminogen activators and both inhibitors; three of the cell lines (T24, EJ, and 253J) expressed the urokinase receptor. The four cell lines differed in their invasive potential in vitro. Neither expression of tissue plasminogen activator nor production of the inhibitors appeared to influence Matrigel invasion. EJ cells and 253J cells produced the highest levels of urokinase and demonstrated the greatest propensity for invasion; T24 cells, which produced only small amounts of urokinase, exhibited a low invasive potential. Pretreatment of T24 cells with exogenous high-molecular-weight urokinase markedly increased their invasiveness. Similar pretreatment of EJ and 253J cells increased their invasiveness as well. RT4 cells, which lacked urokinase receptor expression but produced moderate amounts of urokinase, were not invasive and did not become so after exposure to exogenous high-molecular-weight urokinase. Binding of Mab3936 to urokinase receptors inhibited Matrigel invasion.

CONCLUSIONS

To our knowledge, this is the first study demonstrating that bladder tumor cells express the urokinase receptor and that both receptor expression and urokinase expression are required for bladder tumor cell invasion in vitro.

Prognostic value of urokinase-type plasminogen activator in patients with superficial bladder cancer

OBJECTIVES

A number of studies have demonstrated that urokinase-type plasminogen activator (u-PA) is one of the major enzymes in the development of cancer invasion and metastasis. We examined the possibility that u-PA content is an independent prognostic marker for superficial bladder cancer.

METHODS

The u-PA content was estimated in superficial bladder cancer from 52 patients undergoing transurethral resection for the first time. The survival rates of the patients were calculated and the prognostic values for u-PA content (less than 8 ng/mg protein versus more than 8 ng/mg), Stage (pTa or pT1), grade (1 and 2 versus 3), number (single versus multiple), and size (less than 1 cm versus more than 1 cm) of tumor were determined by a multivariate regression model.

RESULTS

Development of cancer invasion and metastasis was observed in 3 and 8 patients, respectively. The survival rate of the patients with high u-PA content was significantly lower than those with low u-PA content (P < 0.005). In the multivariate regression analysis, u-PA content was the most important risk factor for the prognosis, compared with the other factors: tumor stage, grade, multiplicity, and size.

CONCLUSIONS

We have first shown that u-PA content is a new independent prognostic marker in patients with superficial bladder cancer.

The content of urokinase-type plasminogen activator and tumor recurrence in superficial bladder cancer

The contents of urokinase-type plasminogen activator were estimated in superficial bladder cancer from 42 patients undergoing transurethral resection for the first time. Tumor recurred in 11 of 16 patients (68.8%) with high urokinase-type plasminogen activator content (8 ng. urokinase-type plasminogen activator per mg. protein and more) and in 12 of 26 (46.2%) with low urokinase-type plasminogen activator content. In the high content group 8 patients (50%) had disease progression compared to 2 (7.7%) in the low content group (p < 0.01). The progression rates in the high urokinase-type plasminogen activator group with stage pTa disease or tumors more than 1 cm. large were significantly higher than those in the low urokinase-type plasminogen activator group (p < 0.05). The recurrence and progression rates in the high content group with stage pT1, grades 2 and 3, single and multiple tumors, and tumors less than 1 cm. large were higher than those in the low content group. The progression-free survival rate in the high content group was significantly lower than that in the low content group (p < 0.005). In conclusion, urokinase-type plasminogen activator content may be a useful marker to predict recurrence and progression of superficial bladder cancer.

The content of urokinase-type plasminogen activator antigen as a prognostic factor in urinary bladder cancer

Urokinase-type plasminogen activator (u-PA) is thought to be implicated in cancer invasion and metastasis. The aim of this study was to determine whether the u-PA content of cancer tissue is a prognostic factor in bladder cancer. Tissue samples from 46 patients with bladder cancer were assessed for u-PA antigen by a highly sensitive enzyme immunoassay. The relationships between the u-PA level in extracts of bladder cancer and the survival rates of the bladder-cancer patients were examined. Patients with a high u-PA level (8 ng/mg of protein and more) showed a statistically significantly higher rate of survival than those with a low u-PA level (p less than 0.005). The u-PA antigen level in cancer tissue was significantly lower in low-graded and non-invasive cancers than in others (p less than 0.01).

Immunohistochemical analysis of plasminogen activator expression in human colorectal carcinomas: correlation with CEA distribution and tumor cell kinetics

Fifty cases of colorectal adenocarcinoma were immunohistochemically examined for the relationship between distribution of plasminogen activators (PAs) and the degree of differentiation of cancer cells as reflected by carcinoembryonic antigen (CEA) expression as well as tumor cell kinetics. The A chain of urokinase-type PA (u-PA-A) was mainly observed in the apical portions of highly differentiated cancer cells. Increased expression and change in localization to the cytoplasm were found with progressive dedifferentiation. The numbers of DNA polymerase alpha (pol. alpha) positive cancer cells also increased in line with u-PA-A expression. The B chain of u-PA (u-PA-B), and the A and B chains of tissue-type PA (t-PA-A and -B) did not show similar alteration. The present findings suggest that the distribution of u-PA-A in colorectal carcinoma tissues, the degree of tumor differentiation, and the proliferation kinetics of cancer cells are closely related.

Protease and plasminogen activator activity in human bladder carcinoma

The ability of human bladder tissue extracts to cleave 14C-labelled globin in the absence and in the presence of plasminogen was assayed to quantify non-specific protease and plasminogen activator (PA) activity, respectively. In normal human bladder tissue the non-specific protease activity was approximately 2-fold higher than in tissue samples obtained from transitional cell carcinoma of the bladder (TCC). In contrast, PA activity was almost 4-fold higher in TCC than in normal transition cell epithelium. Acid-treated urine from 19 patients with TCC of the bladder exhibited significantly higher levels of plasminogen activator activity than similarly treated urine from controls. These results indicate that malignant transformation of the bladder epithelial tissue results in elevated levels of PA in the tissue and in urine. Further studies are needed to assess the potential of PA determination in the management of bladder cancer patients.

[Plasminogen activators: general aspects and recent developments]

Considerable interest in plasminogen activators as human thrombolytic drugs has stimulated rapid biotechnologic progresses. These enzymes have been classified in two immunochemically distinct groups: "urokinase-like" activators or u-PA which do not interact with fibrin and "tissue activator-like" activators or t-PA which interact with fibrin. Plasminogen activators are widely distributed in normal and malignant tissues and they are implicated in various physiological and pathological processes. They maintain the functional integrity of the vascular system and their presence may be of importance in tissue remodeling and cell migration. Urokinase and streptokinase are used in human thrombolytic therapy. However, the properties displayed by t-PA suggest that this enzyme may be a superior fibrinolytic agent. The primary structures of urokinase and t-PA are known; both enzymes have been synthesized by DNA technology. In order to produce t-PA in large quantities by gene cloning, intensive studies are conducted by pharmaceutical industries. Clinical trials using t-PA for dissolving thrombi in coronary heart disease, strokes and pulmonary embolism are in progress. This review presents the molecular and structural properties of plasminogen activators, as well as related physiological, pathological and therapeutic aspects.

Characterization of plasminogen activators from normal human breast and colon and from breast and colon carcinomas

Triton X-100 and NaSCN extracts of 18 normal breast and colon tissues and of 20 breast and colon carcinomas were fractionated by SDS-PAGE and plasminogen activators (PA) revealed by a zymographic method. Four different lysis bands, corresponding to MWs of 54,000, 68,000, 95,000 and 110,000 were observed. Using immunoadsorption with specific antisera against urokinase (UK) and tissue PA (t-PA), we found that all normal tissue extracts contained free t-PA (68 kd). Some of these revealed, in addition, a complex (110 kd) of t-PA with a 40-kd component. The latter presumably represents the fast-acting specific inhibitor of t-PA and UK. Most carcinoma extracts contained, in addition to the two t-PA-related lysis bands, the UK-related 54 kd PA, and some a 95 kd complex of UK with the 40 kd component. For each extractant, mean total fibrinolytic activity of normal and tumor tissue was comparable when measured on conventional fibrin plates, but breast and colon carcinomas contained higher concentrations of UK-related PA. PA activity was higher in normal and carcinoma NaSCN extracts than in the corresponding Triton X-100 extracts. In general, Triton X-100 but not NaSCN extracts of malignant tissue contained a high concentration of fibrinolytic inhibitors. Mixing experiments revealed that the inhibitory activity was mainly directed against UK. It was abolished by acidification of the carcinoma extracts. The anti-UK inhibitory activity was absent in extracts of normal breast or colon and appears to be different from the 40 kd fast-acting PA inhibitor. These studies show that malignant transformation of breast and colon is accompanied by important changes of the production of a UK-related PA and of an inhibitory activity directed against UK.

Invasiveness of transformed bladder epithelial cells

The invasiveness of bladder tumors has been studied in man, experimental animals, and in tissue culture by numerous authors. The prognostic importance of cellular markers for invasiveness is stressed, and the usefulness of histopathological and cytologic grading, cytogenetic studies, antigenic investigations, and enzymatic characterization is discussed. The invasiveness of bladder cells has frequently been examined in transplantation and explantation experiments. In human urothelial cell cultures three grades of transformation are defined, and a correlation has been established between the invasiveness of these cell lines in a three-dimensional in vitro model and their tumorigenicity in nude mice. The mechanism of tumor invasion is discussed, and it is recommended in future research to make a distinction between invasion en bloc and cellular infiltration.

Human renal cell carcinoma: establishment and characterization of two new cell lines

Characterization studies have been carried out on 2 cell lines (KPK 1 and KPK 13) established from human renal adenocarcinoma. KPK 1 and KPK 13 have been passaged 178 times in vitro for about 6 years and 7 months and 78 times for about 3 years an 2 months, respectively. Although morphologic differences exist between the 2 lines, each has an epithelial morphology and exhibits multilayering. Doubling time of KPK 1 and KPK 13 cells was 29 hours and 51 hours, respectively. Both KPK 1 and KPK 13 induced tumors at the site of subcutaneous injection, closely resembling the original tumor from which they were derived. Chromosome number of both cell lines was 100 per cent aneuploid and the presence of Y chromosomes was confirmed by G banding in KPK 13 cells. KPK 1 was found to have high thromboplastic and high fibrinolytic activities, whereas KPK 13 was shown to have comparatively low thromboplastic and no detectable fibrinolytic activities. These activities were detected in the serum free supernatant fraction from KPK 1 cells but were not detected in that from KPK 13 cells.