Lumican core protein inhibits melanoma cell migration via alterations of focal adhesion complexes

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• 作者：Sté ; phane Bré ; zillon ; Agata Radwanska ; Cedric Zeltz ; Andrzej Malkowski ; Dominique Ploton ; Hé ; lè ; ne Bobichon ; Corinne Perreau ; Maria Malicka-Blaszkiewicz ; Franç ; ois-Xavier Maquart
• 关键词：Extracellular matrix ; Focal adhesion ; Integrin ; Lumican ; Melanoma
• 刊名：Cancer Letters
• 出版年：2009
• 出版时间：28 September 2009
• 年：2009
• 卷：283
• 期：1
• 页码：92-100
• 全文大小：1769 K

文摘

Lumican is a small leucine-rich proteoglycan (SLRP) of the extracellular matrix (ECM) with anti-tumor activity. We recently demonstrated that lumican inhibits the migration of melanoma cells and identified β1 integrin as mediator of this effect [M.F. D’Onofrio, S. Brézillon, T. Baranek, C. Perreau, P.J. Roughley, F.X. Maquart, Y. Wegrowski, Identification of β1 integrin as mediator of melanoma cell adhesion to lumican, Biochem. Biophys. Res. Commun. 365 (2008) 266–272]. The aim of the present work was to study β1 integrin, focal adhesion complexes, actin distribution and expression in the presence of lumican substratum in comparison to type I collagen or fibronectin substrata in A375 human melanoma cells. The protein distribution was investigated by immunocytochemistry and confocal microscopy. In parallel, their expression was evaluated by Western immunoblotting and Real-time Reverse Transcription-PCR analyses. The interaction of melanoma cells with the lumican substratum resulted in heterogeneous distribution of β1 integrin on cell membrane after 24 h of seeding. Concomitantly, a reorganization of actin stress fibers and a significant decrease in vinculin immunostaining at focal adhesion complexes were observed. No alteration of the expression was detected at protein and mRNA levels. However, a cytosolic accumulation of vinculin focal adhesion protein was observed on lumican substratum by confocal microscopy. Moreover, vinculin expression was significantly increased in cytosolic fractions in comparison to cells seeded on type I collagen or fibronectin substrata. Our results suggest that lumican induces an alteration of the link between actin filaments and β1 integrin, characterized by a cytosolic accumulation of vinculin focal adhesion protein, which could lead to a destabilization of focal adhesion complexes. In addition, focal adhesion kinase phosphorylated at tyrosine-397 (pFAK) was significantly decreased. Therefore, the cytoskeleton remodeling and the decreased pFAK phosphorylation induced by lumican in melanoma cells might explain, at least in part, the anti-invasive effect of this SLRP.