Tumour necrosis factor alpha confers an invasive, transformed phenotype on mammary epithelial cells.
Although loss of cell-cell adhesion and gain of invasive properties play a crucial role in the malignant progression of epithelial tumours, the molecular signals that trigger these processes have not been fully elucidated. In light of the well-established relationship between chronic inflammation and cancer, we hypothesized that pro-inflammatory cytokines disrupt epithelial-cell adhesion and promote cell migration. To test this hypothesis, we used an in vitro model in which 31EG4-2A4 mouse mammary epithelial cells grown in a collagen gel form compact spheroidal colonies. Among the several cytokines examined, tumour necrosis factor alpha (TNF-alpha) caused a pronounced 3D scattering of preformed epithelial-cell colonies and induced 31EG4-2A4 cells grown on top of a collagen gel to invade the underlying matrix. In addition, TNF-alpha abolished contact-mediated inhibition of cell proliferation and stimulated cell growth both in the absence of exogenous mitogens and under anchorage-independent conditions. TNF-alpha induced the expression of matrix metalloproteinase 9 (MMP-9). Addition of the MMP inhibitor BB-94 abrogated TNF-alpha-induced 3D scattering. TNF-alpha also enhanced the attachment of 31EG4-2A4 cells to type-I collagen and markedly increased the expression of the alpha2 integrin subunit. Addition of a blocking antibody to beta1-integrin or of rhodocetin (a specific alpha2beta1 antagonist) to collagen-gel cultures abrogated 3D scattering. Collectively, these results demonstrate an essential role for MMPs and alpha2beta1 integrin in the invasive response of 31EG4-2A4 cells to TNF-alpha. We propose that the biological activities described in this study contribute to the ability of TNF-alpha to promote tumour progression and cancer-cell dissemination.
Montesano
Roberto
R
Department of Cell Physiology and Metabolism, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland. roberto.montesano@medecine.unige.ch
Soulié
Priscilla
P
Eble
Johannes A
JA
Carrozzino
Fabio
F
D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D003094:Collagen / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D038982:Integrin alpha2beta1 / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D045726:Metalloproteases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D010641:Phenotype; D011480:Protease Inhibitors / Q000494:pharmacology; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D038982:Integrin alpha2beta1; D011480:Protease Inhibitors; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D003094:Collagen; D045726:Metalloproteases