Transforming growth factor-beta 1 inhibits generation of angiostatin by human pancreatic cancer cells.

Abstract

BACKGROUND:

Angiostatin, a proteolytic fragment of plasminogen, is a potent inhibitor of angiogenesis. We have previously shown that the human pancreatic cancer cell line ASPC-1 produces enzymatic activity capable of generating angiostatin. In this study we sought to determine whether angiostatin production by ASPC-1 cells was regulated by the growth factor transforming growth factor-beta 1 (TGF-beta 1), a key mediator of tumor angiogenesis.

METHODS:

ASPC-1 cells were grown to 70% to 80% confluence in 20% fetal calf serum-RPMI. Medium was changed to serum free. TGF-beta 1 was added at concentrations of 0, 1, 5, and 10 ng/mL with or without plasminogen activator inhibitor type-1 (PAI-1) at concentrations of 0, 5, 10, 50, and 100 micrograms/mL. Cells were then cultured for an additional 24 hours. The serum-free conditioned medium was obtained. Angiostatin generation was determined by incubating 20 micrograms of plasminogen with 100 microL of serum-free conditioned medium for 0, 1, 2, 3, 6, 12, and 24 hours. Samples were run on 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred. The membrane was probed with a monoclonal antibody to the kringle 1-3 fragment of plasminogen and developed using enhanced chemiluminescence.

RESULTS:

TGF-beta 1 and PAI-1 inhibited the conversion of plasminogen into angiostatin in a time- and dose-dependent manner. Antibody to PAI-1 completely blocks TGF-beta 1 mediated angiostatin inhibition.

CONCLUSIONS:

TGF-beta 1 inhibits the generation of the antiangiogenic molecule angiostatin by human pancreatic cancer cells in a time- and dose-dependent manner. This effect is mediated through modulation of the plasminogen/plasmin system.

• Authors: C A O'Mahony, D Albo, G P Tuszynski, D H Berger
• Journal: Surgery (Surgery) Vol. 124 Issue 2 Pg. 388-93 (Aug 1998) ISSN: 0039-6060 [Print] United States
• PMID: 9706163 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies
• Antineoplastic Agents
• Peptide Fragments
• Plasminogen Activator Inhibitor 1
• Serine Proteinase Inhibitors
• Transforming Growth Factor beta
• Angiostatins
• Plasminogen

Topics

• Adenocarcinoma
• Angiostatins
• Antibodies (pharmacology)
• Antineoplastic Agents (analysis, metabolism)
• Blotting, Western
• Dose-Response Relationship, Drug
• Humans
• Neovascularization, Pathologic (enzymology, physiopathology)
• Pancreatic Neoplasms
• Peptide Fragments (analysis, biosynthesis, metabolism)
• Plasminogen (analysis, biosynthesis, metabolism)
• Plasminogen Activator Inhibitor 1 (immunology, pharmacology)
• Serine Proteinase Inhibitors (immunology, pharmacology)
• Transforming Growth Factor beta (pharmacology)
• Tumor Cells, Cultured (drug effects, metabolism)