Loss of adhesion-regulated proteinase production is correlated with invasive activity in oral squamous cell carcinoma.
BACKGROUND
Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity. However, the cellular and biochemical factors that underlie locoregional and distant spread of the disease are poorly understood. Invasion of OSCC requires multiple cellular events including dissolution of cell-cell junctions, basement membrane attachment, extracellular matrix proteolysis, and migration.


METHODS
We evaluated these properties in vitro using premalignant gingival keratinocytes (ppl26) and two OSCC lines (SCC15 and SCC68). Expression of adhesion molecules integrins and cadherins, cytoplasmic intermediate filaments (IF) vimentin and keratin as well as matrix degrading proteins were evaluated. Moreover, regulation of protease production by adhesion molecules was tested.


RESULTS
All cell lines contained comparable levels of the epithelial cell-cell adhesion molecule, E-cadherin. Differential expression of cytoplasmic IF was evident between premalignant pp126 cells and OSCC cell lines. Expression levels of the alpha3beta1 integrin, utilized for attachment to laminin-5 and other matrix proteins, was high in SCC68 cells, moderate in SCC15 cells, and low in ppl26 cells. alpha3beta1 integrin clustering up-regulates expression of urinary-type plasminogen activator (uPA) in ppl26 cells via a mechanism involving ERK activation. Both ppl26 and SCC15 cells were responsive to alpha3beta1 clustering, resulting in enhanced uPA expression. However, basal uPA levels were high in SCC68 cells and integrin clustering did not further stimulate uPA production. ERK was constitutively activated in SCC68 cells and treatment of cells with an inhibitor of ERK activation (PD98059) reduced uPA expression. Consistent with the enhanced proteolytic potential, SCC68 cells readily penetrated Matrigel and invasion was blocked by an anticatalytic uPA antibody.


CONCLUSIONS
These data suggest that loss of adhesion-regulated proteinase production may lead to elevated pericellular proteinase activity and coincident alterations in cytoskeletal IF protein expression, thereby contributing to the invasive potential of OSCC.
Ghosh
Supurna
S
Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Munshi
Hidayatullah G
HG
Sen
Ratna
R
Linz-McGillem
Laura A
LA
Goldman
Robert D
RD
Lorch
Jochen
J
Green
Kathleen J
KJ
Jones
Jonathan C R
JC
Stack
M Sharon
MS
D015820:Cadherins / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion / Q000502:physiology*; D003094:Collagen; D015536:Down-Regulation; D004338:Drug Combinations; D010450:Endopeptidases / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D007365:Intercellular Junctions; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D007797:Laminin / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009061:Mouth Mucosa / Q000166:cytology* / Q000473:pathology; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D011480:Protease Inhibitors / Q000378:metabolism; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
D015820:Cadherins; D004338:Drug Combinations; D016023:Integrins; D007797:Laminin; D011480:Protease Inhibitors; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins; C059485:matrigel; D003094:Collagen; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010450:Endopeptidases; D014568:Urokinase-Type Plasminogen Activator