Combination Effect of Cilengitide with Erlotinib on TGF-β1-Induced Epithelial-to-Mesenchymal Transition in Human Non-Small Cell Lung Cancer Cells

The epithelial-to-mesenchymal transition (EMT) is important for morphogenesis during development and is mainly induced by transforming growth factor (TGF)-β. In lung cancer, EMT is characterized by the transformation of cancer cells into a mobile, invasive form that can transit to other organs. Here, using a non–small cell lung cancer (NSCLC) cell line, we evaluated the EMT-related effects of the epidermal growth factor receptor inhibitor erlotinib alone and in combination with cilengitide, a cyclic RGD-based integrin antagonist. Erlotinib showed anti-proliferative and inhibitory effects against the TGF-β1–induced EMT phenotype in NSCLC cells. Compared with erlotinib alone, combination treatment with cilengitide led to an enhanced inhibitory effect on TGF-β1–induced expression of mesenchymal markers and invasion in non–small cell lung cancer A549 cells. These results suggest that cilengitide could improve anticancer drug efficacy and contribute to improved treatment strategies to inhibit and prevent EMT-based cancer progression.