Lumican inhibits cell migration through α2β1 integrin.
Lumican, an extracellular matrix protein of the small leucine-rich proteoglycan family, has been shown to impede melanoma progression by inhibiting cell migration. In the present study, we show that lumican targets α2β1 integrin thereby inhibiting cell migration. A375 melanoma cells were transfected with siRNA directed against the α2 integrin subunit. Compared to A375 control cells, the anti-migratory effect of lumican was abrogated on transfected A375 cells. Moreover, lumican inhibited the chemotactic migration of Chinese hamster ovary (CHO) cells stably transfected with α2 integrin subunit (CHO-A2) but not that of wild-type CHO cells (CHO-WT) lacking this subunit. In contrast to CHO-WT cells, we observed in time-lapse microscopy a decrease of CHO-A2 cell migration speed in presence of lumican. Focal adhesion kinase phosphorylated at tyrosine-397 (pFAK) and total FAK were analysed in CHO-WT and CHO-A2 cells. A significant decrease of the ratio pFAK/FAK was shown in presence of recombinant human lumican. Using solid phase assays, a direct binding between lumican and the α2β1 integrin was demonstrated. This interaction did not involve the glycan moiety of lumican and was cation independent. Lumican was also able to bind the activated I domain of the α2 integrin subunit with a K(d)≥200nM. In conclusion, we demonstrated for the first time that the inhibition of cell migration by lumican depends on a direct binding between the core protein of lumican and the α2β1 integrin.
Zeltz
Cédric
C
CNRS UMR 6237 MEDyC, Université de Reims-Champagne-Ardenne, Reims, France.
Brézillon
Stéphane
S
Käpylä
Jarmo
J
Eble
Johannes A
JA
Bobichon
Hélène
H
Terryn
Christine
C
Perreau
Corinne
C
Franz
Clemens M
CM
Heino
Jyrki
J
Maquart
François-Xavier
FX
Wegrowski
Yanusz
Y
D000818:Animals; D016466:CHO Cells; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D011508:Chondroitin Sulfate Proteoglycans / Q000494:pharmacology*; D006224:Cricetinae; D003412:Cricetulus; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D006801:Humans; D039421:Integrin alpha2 / Q000378:metabolism; D038982:Integrin alpha2beta1 / Q000378:metabolism*; D007632:Keratan Sulfate / Q000494:pharmacology*; D000071234:Lumican; D008545:Melanoma; D010766:Phosphorylation; D011485:Protein Binding
D011508:Chondroitin Sulfate Proteoglycans; D039421:Integrin alpha2; D038982:Integrin alpha2beta1; C000604306:LUM protein, human; D000071234:Lumican; D007632:Keratan Sulfate; D051416:Focal Adhesion Protein-Tyrosine Kinases