['Cell-matrix interactions are in part mediated through the beta1-integrin pathway regulating cell survival, proliferation, adhesion and migration. This study was performed to elucidate alterations of expression of the beta1-integrin and its co-localized protein kinase, integrin-linked kinase (ILK), after exposure to ionizing radiation in two lung carcinoma cell lines in the presence or absence of different beta1-integrin-dependent matrix proteins.', 'Exponentially growing A549 and SKMES1 cells grown on fibronectin, laminin, BSA or plastic were exposed to 2 Gy or 6 Gy. Besides colony formation assays (0.5-8 Gy) and immediate plating experiments, flow cytometry (for beta1-integrin) and immunoblotting (for beta1-integrin and ILK) were carried out to analyze the protein expression. The localization of both proteins plus filamentous (f-) actin was further examined by immunofluorescence staining and laser confocal scanning microscopy. Functionality of the beta1 receptor subunit after irradiation was investigated in adhesion assays.', 'A549 and SKMES1 cells grown on fibronectin or laminin demonstrated a significant increase in cell survival after irradiation compared to cells grown on BSA or plastic. Immediate plating of cells after irradiation on fibronectin did not show an improved survival. Flow cytometric and Western blot data showed a dose- and matrix-dependent induction of beta1-integrin and ILK expression after irradiation within 48 h. Adhesion to fibronectin or laminin compared to BSA or plastic was increased by 10-fold after irradiation, demonstrating these specific cell surface receptors to be functional. The staining of beta1-integrin and ILK in A549 cells confirmed the radiation-induced up-regulation of both proteins. Additionally, beta1-integrin and ILK co-localized with accumulated actin fibers at the cytoplasmic face of the cell membrane at confined areas.'] Does ionizing radiation induce up-regulation of functional beta1-integrin in human lung tumour cell lines in vitro?