The plasminogen activator urokinase is overexpressed in many malignancies including that of the colon. Urokinase may be involved in tumor metastases as evidenced by the ability of anti-urokinase antibodies to block this phenomenon in chicken embryos. A specific binding site for the plasminogen activator has been identified and may be crucial for the actions of urokinase. Although the cellular controls of urokinase and its receptor are poorly understood, they represent ideal therapeutic targets and may ultimately yield anti-metastatic agents. The regulation of expression of urokinase and its receptor in colon cancer will be investigated. Poorly differentiated colon cancer cells, but not their well differentiated counterparts, express elevated levels of urokinase in a constitutive manner. These cells are characterized as secreting and responding to TGF- a. The objective of specific aim #1 is to determine whether constitutive production of this plasminogen activator in some colon cancers is a consequence of stimulation by autocrine TGF-a. Poorly differentiated cells display 10X more urokinase receptors than well differentiated cell types. Preliminary studies show that urokinase is a negative regulator of its receptor in well differentiated cells. The ability of urokinase to reduce receptor number in poorly differentiated cells will be determined in specific aim #2. Studies will be undertaken to determine what part of the urokinase molecule is responsible for receptor modulation. These binding sites may fix the plasminogen activator on the cell surface, thereby facilitating local proteolysis. Indeed, all of the cultured colon cancer cell lines degrade laminin, in the presence of plasminogen. The anti- laminin degrading activity of a peptide which binds to the receptor, but has no active site, will be tested in specific aim #3. Analysis of receptor expression is currently hampered by the lack of molecular probes such as antibodies and cDNA's. This is due, in part, to the lack of purified receptor.
In specific aim #4, the urokinase receptor will be purified to homogeneity from a colon cancer cell line. Monoclonal antibodies will be raised against the binding site.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29CA051539-05
Application #
3459793
Study Section
Metabolic Pathology Study Section (MEP)
Project Start
1989-12-01
Project End
1994-11-30
Budget Start
1992-12-01
Budget End
1993-11-30
Support Year
5
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Type
Other Domestic Higher Education
DUNS #
001910777
City
Houston
State
TX
Country
United States
Zip Code
77030
Simon, C; Juarez, J; Nicolson, G L et al. (1996) Effect of PD 098059, a specific inhibitor of mitogen-activated protein kinase kinase, on urokinase expression and in vitro invasion. Cancer Res 56:5369-74
Lengyel, E; Klostergaard, J; Boyd, D (1995) Stimulation of urokinase expression by TNF-alpha requires the activation of binding sites for the AP-1 and PEA3 transcription factors. Biochim Biophys Acta 1268:65-72
Wang, H; Skibber, J; Juarez, J et al. (1994) Transcriptional activation of the urokinase receptor gene in invasive colon cancer. Int J Cancer 58:650-7
Clayman, G; Wang, S W; Nicolson, G L et al. (1993) Regulation of urokinase-type plasminogen activator expression in squamous-cell carcinoma of the oral cavity. Int J Cancer 54:73-80
Juarez, J; Clayman, G; Nakajima, M et al. (1993) Role and regulation of expression of 92-kDa type-IV collagenase (MMP-9) in 2 invasive squamous-cell-carcinoma cell lines of the oral cavity. Int J Cancer 55:10-8
Kariko, K; Kuo, A; Boyd, D et al. (1993) Overexpression of urokinase receptor increases matrix invasion without altering cell migration in a human osteosarcoma cell line. Cancer Res 53:3109-17
Hollas, W; Soravia, E; Mazar, A et al. (1992) Decreased urokinase receptor expression by overexpression of the plasminogen activator in a colon cancer cell line. Biochem J 285 ( Pt 2):629-34
Hoosein, N M; Boyd, D D; Hollas, W J et al. (1991) Involvement of urokinase and its receptor in the invasiveness of human prostatic carcinoma cell lines. Cancer Commun 3:255-64
Hollas, W; Blasi, F; Boyd, D (1991) Role of the urokinase receptor in facilitating extracellular matrix invasion by cultured colon cancer. Cancer Res 51:3690-5
Schlechte, W; Brattain, M; Boyd, D (1990) Invasion of extracellular matrix by cultured colon cancer cells: dependence on urokinase receptor display. Cancer Commun 2:173-9

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