Epidermal growth factor receptor signaling and the invasive phenotype of ovarian carcinoma cells.
BACKGROUND
Most (70%-100%) ovarian carcinomas express high levels of the epidermal growth factor receptor (EGFR). To examine the relationship between EGFR and the invasive phenotype, we assessed integrin expression, adhesion, matrix metalloproteinase (MMP) activity, and migration in ovarian cancer cells in which EGFR expression was modified.


METHODS
NIH:OVCAR-8 human ovarian carcinoma cells were transfected with an expression vector containing the human EGFR complementary DNA in an antisense orientation (EGFR-antisense cells) or the vector alone (vector control cells). We compared vector control and EGFR-antisense cells for cell morphology and adhesion by light microscopy, expression of alpha(6)- and alpha(3)-integrin subunits by flow cytometry, MMP and tissue inhibitor of MMP (TIMP) activity by zymography, and migration by a wound migration assay. In some experiments, EGFR kinase activity in parental cells was inhibited by treatment with PD153035. All statistical tests were two-sided.


RESULTS
EGFR-antisense cells were morphologically distinct from vector control cells and had a selective decrease in adhesion to laminin-1 that was not observed with vector control cells (P = .008) or on other extracellular matrix substrates. Compared with vector control cells, cell surface alpha(6)-integrin expression decreased by approximately 80% (difference = 78.7%; 95% confidence interval [CI] = 77.8% to 79.6), MMP-9 activity decreased by approximately 50%, and TIMP activity increased by approximately 50% in EGFR-antisense cells. Vector control cells were highly motile (5.51 arbitrary distance unit; 95% CI = 4.98 to 6.04), whereas the EGFR-antisense cells were not (0.99 arbitrary distance units; 95% CI = 0.38 to 1.60). The morphology and integrin profile of NIH:OVCAR-8 parental cells treated with PD153035 were similar to those of the EGFR-antisense cells.


CONCLUSIONS
Reduced EGFR expression in ovarian carcinoma cells decreased their adhesion to laminin-1, expression of the alpha(6)-integrin subunit (a well-characterized laminin-1 receptor), and MMP-9 activity. These data support the hypothesis that EGFR overexpression in ovarian cancer cells results in multiple phenotypic changes that enhance the invasive phenotype.
Alper O
Department of Oncology, Georgetown University, Washington DC, USA.
Bergmann-Leitner
E S
ES
Bennett
T A
TA
Hacker
N F
NF
Stromberg
K
K
Stetler-Stevenson
W G
WG
D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D019898:Autocrine Communication; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D002448:Cell Adhesion; D002465:Cell Movement; D048429:Cell Size; D016373:DNA, Antisense / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000737:chemistry; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D039422:Integrin alpha3; D039503:Integrin alpha6; D016023:Integrins / Q000096:biosynthesis / Q000235:genetics; D007797:Laminin / Q000737:chemistry; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000235:genetics; D009361:Neoplasm Invasiveness / Q000235:genetics*; D009363:Neoplasm Proteins / Q000009:adverse effects / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology*; D010641:Phenotype; D011799:Quinazolines / Q000494:pharmacology; D015398:Signal Transduction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis / Q000235:genetics; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D015703:Antigens, CD; D016373:DNA, Antisense; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D039422:Integrin alpha3; D039503:Integrin alpha6; D016023:Integrins; D007797:Laminin; D009363:Neoplasm Proteins; D011799:Quinazolines; D019715:Tissue Inhibitor of Metalloproteinase-1; C121346:laminin 1; D019716:Tissue Inhibitor of Metalloproteinase-2; D066246:ErbB Receptors; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; C088860:4-((3-bromophenyl)amino)-6,7-dimethoxyquinazoline