The epithelial to mesenchymal transition (EMT) involves several physiological and pathological phenomena and endows cells with invasive and migratory properties. However, the effects of substrate stiffness and topography on the migration of cells before or after transforming growth factor-β1 (TGF-β1)-induced EMT (tEMT) are unknown. Herein, we seed control or tEMT NMuMG cells on the 2D patterns consisted of 1 μm or 5 μm line-widths and groove or cone patterns on either 2 MPa (1.96 ± 0.48 MPa) or 4 MPa (3.70 ± 0.74 MPa) polydimethylsiloxane (PDMS) substrates. After tEMT, the increased expression of α-SMA with vinculin in focal adhesion (FA) sites led to an acceleration of tEMT cell motility. On the 2 MPa substrate, the most influenced substrate was the 1 μm, cone-patterned substrate, where the tEMT cells' motility decelerated by 0.13 μm/min (36% slower than the cells on groove pattern). However, on the 5 μm, groove-patterned substrate, where the tEMT cells demonstrated the most rapid motility relative to the control cells, with an increment of 0.18 μm/min (100%). Among the different physical cues from substrate, the cone pattern could impede the migration speed of tEMT cells. Furthermore, we recommend the groove-patterned with a 5 μm line-width substrate as a useful tool to differentiate control and tEMT cells by migration speed.

BackgroundIn vivo, the transforming growth factor-beta1 (TGF-β1)-induced epithelial to mesenchymal transition (EMT) occurs in seconds during cancer cells intravasation and extravasation. Although it has been established that cellular stiffness can change as a cancer cell transformed, the precise relationship between TGF-β1-induced mesenchymal stem cell mechanics and cancer prognosis remains unclear. Accordingly, it is hard to define the effects of EMT on cell mechanical properties (CMs), tumor recurrence and metastasis risks. This study bridges physical and pathological disciplines to reconcile single-cell mechanical measurements of tumor cells.Methods and resultsWe developed a microplate measurement system (MMS) and revealed the intrinsic divergent tumor composition of retrieval cells by cell stiffness and adhesion force and flow cytometry analysis. After flow cytometry sorting, we could measure the differences in CMs of the Sca-1+-CD44+ (mesenchymal-stem-cell-type) and the other subgroups. As well as the stiffer and heterogeneous compositions among tumor tissues with higher recurrence risk were depicted by MMS and atomic force microscopy (AFM). An in vitro experiment validated that Lewis lung carcinoma (LLC) cells acquired higher CMs and motility after EMT, but abrogated by SB-505124 inhibition. Concomitantly, the CD31, MMP13 and TGF-β1 enriched micro-environment in the tumor was associated with higher recurrence and distal lung metastasis risks. Furthermore, we report a comprehensive effort to correlate CMs to tumor-prognosis indicators, in which a decreased body weight gain ratio (BWG) and increased tumor weight (TW) were correlated with increased CMs.ConclusionsTogether, we determined that TGF-β1 was significantly associated with malignant tumor progressing. In terms of clinical applications, local tumor excision followed by MMS analysis offers an opportunity to predict tumor recurrence and metastasis risks.