Abstract | INTRODUCTION: METHODS: RESULTS: Both cell lines expressed comparable levels of cathepsin B and uPA. In contrast, levels of caveolin-1 and uPAR were greater in SUM149 cells. We observed that uPA, uPAR and enzymatically active cathepsin B were colocalized in caveolae fractions isolated from SUM149 cells. Using a live-cell proteolysis assay, we demonstrated that both IBC cell lines degrade type IV collagen. The SUM149 cells exhibit predominantly pericellular proteolysis, consistent with localization of proteolytic pathway constitutents to caveolar membrane microdomains. A functional role for cathepsin B was confirmed by the ability of CA074, a cell impermeable and highly selective cathepsin B inhibitor, to significantly reduce pericellular proteolysis and invasion by SUM149 cells. A statistically significant co-expression of cathepsin B and caveolin-1 was found in IBC patient biopsies, thus validating our in vitro data. CONCLUSION: Our study is the first to show that the proteolytic activity of cathepsin B and its co-expression with caveolin-1 contributes to the aggressiveness of IBC.
|
Authors | Bernadette C Victor, Arulselvi Anbalagan, Mona M Mohamed, Bonnie F Sloane, Dora Cavallo-Medved |
Journal | Breast cancer research : BCR
(Breast Cancer Res)
Vol. 13
Issue 6
Pg. R115
( 2011)
ISSN: 1465-542X [Electronic] England |
PMID | 22093547
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
|
Chemical References |
- CA 074 methyl ester
- Caveolin 1
- Collagen Type IV
- Dipeptides
- Integrin beta Chains
- Receptors, Urokinase Plasminogen Activator
- Urokinase-Type Plasminogen Activator
- Cathepsin B
|
Topics |
- Cathepsin B
(antagonists & inhibitors, genetics, metabolism)
- Caveolae
(metabolism)
- Caveolin 1
(metabolism)
- Cell Line, Tumor
- Collagen Type IV
(metabolism)
- Dipeptides
(pharmacology)
- Extracellular Matrix
(metabolism)
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Inflammatory Breast Neoplasms
(genetics, metabolism, pathology)
- Integrin beta Chains
(metabolism)
- Neoplasm Invasiveness
- Protein Binding
- Protein Transport
- Proteolysis
- Receptors, Urokinase Plasminogen Activator
(metabolism)
- Urokinase-Type Plasminogen Activator
(metabolism)
|