Klominek J, Sumitran Karuppan S, Hauzenberger D
Department of Lung Medicine, Karolinska Institute at Huddinge University Hospital, Sweden.
Int J Cancer. 1997 Sep 17;72(6):1034-44. doi: 10.1002/(sici)1097-0215(19970917)72:6<1034::aid-ijc19>3.0.co;2-4.
Beta1 integrins are widely expressed in human tissues but their presence and function on malignant mesothelioma cells have not been examined. In this study, we have investigated the expression and function of beta1 integrins in 7 human malignant mesothelioma cell lines. Immunofluorescence staining and FACS analysis showed similar expression of beta1 integrins with strongest expression of alpha3beta1 in all investigated mesothelioma cell lines. Using the Boyden chamber assay, we found that mesothelioma cell lines migrated to soluble (chemotaxis) and substrate-bound (haptotaxis) fibronectin, laminin and collagen type IV. In order to investigate the biological function of integrins in mesothelioma cells, we pre-incubated the cells with blocking anti-integrin monoclonal antibodies (MAbs) prior to the adhesion and migration assays. Anti-beta1 antibodies inhibited cell adhesion, chemotaxis and haptotaxis in all cell lines. Generally, anti-alpha2 integrin antibodies inhibited cell adhesion, chemotactic and haptotactic migration to collagen type IV, whereas antibodies to the alpha5 and alpha6 subunits inhibited cell adhesion and migration to fibronectin and laminin, respectively. Preincubation of mesothelioma cells with anti-alpha3 antibodies inhibited the migration to either collagen type IV, laminin or fibronectin in all cell lines. Interestingly, in 3 cell lines anti-alpha3 antibodies inhibited cell migration to laminin and collagen type IV without affecting the ability of the cells to adhere to these proteins. Furthermore, in 2 cell lines, antibodies to the alpha3 chain inhibited chemotaxis but not haptotaxis to collagen type IV, indicating the presence of distinct signalling pathways.
β1整合素在人体组织中广泛表达，但它们在恶性间皮瘤细胞中的存在及功能尚未得到研究。在本研究中，我们调查了β1整合素在7种人恶性间皮瘤细胞系中的表达及功能。免疫荧光染色和流式细胞术分析显示，在所有研究的间皮瘤细胞系中，β1整合素表达相似，其中α3β1表达最强。使用博伊登小室试验，我们发现间皮瘤细胞系可迁移至可溶性（趋化性）和底物结合型（趋触性）纤连蛋白、层粘连蛋白和IV型胶原。为了研究整合素在间皮瘤细胞中的生物学功能，我们在黏附及迁移试验前，用封闭性抗整合素单克隆抗体（MAb）对细胞进行预孵育。抗β1抗体抑制了所有细胞系中的细胞黏附、趋化性和趋触性。一般来说，抗α2整合素抗体抑制细胞黏附、向IV型胶原的趋化性和趋触性迁移，而抗α5和α6亚基的抗体分别抑制细胞黏附及向纤连蛋白和层粘连蛋白的迁移。用抗α3抗体对间皮瘤细胞进行预孵育，抑制了所有细胞系向IV型胶原、层粘连蛋白或纤连蛋白的迁移。有趣的是，在3种细胞系中，抗α3抗体抑制细胞向层粘连蛋白和IV型胶原的迁移，但不影响细胞黏附这些蛋白的能力。此外，在2种细胞系中，抗α3链抗体抑制向IV型胶原的趋化性，但不抑制趋触性，表明存在不同的信号通路。
