Epithelial–mesenchymal Transition of HeLa Cells Increases Traction Force to the ECM in 3D Collagen Gel

Abstract

Metastasis is initiated by an invasion of cancer cells from a primary lesion through the interstitial extracellular matrix (ECM) due to metastatic potential in a process termed the epithelial–mesenchymal transition (EMT). The EMT consists of biomechanical interactions between the ECM and migrating cancer cells as they push and pull their way through ECM collagen fibers. The traction force between a cancer cell and the ECM is a vital parameter in these biomechanical interactions. Therefore, several studies have examined the traction force of various cancer cells before and after EMT using two-dimensional (2D) or 2.5D culture; however, these traction forces have not yet been explored using 3D culture. In this study, we investigated traction force changes in cancer, human cervical cancer (HeLa), and human breast adenocarcinoma (MCF-7) cells before and after EMT in a 3D collagen gel. EMT was induced in HeLa cells using transforming growth factor-β (TGF-β); the addition of TGF-β increased traction forces. Increased cell traction forces by EMT could contribute to enhanced invasiveness and metastasis among cancer cells. This study provides valuable insight into traction forces in identical cancer cell lines surrounded by a collagen-rich ECM network before and after EMT.