Adhesivity of colon cancer cells during in vitro metastasis

Human colon carcinoma (HCT-8) cells show a stable, metastasis-like phenotype (MLP) when cultured on appropriate soft substrates (21 ∼ 47 kPa). Initially epithelial (E) in nature, the HCT-8 cells become rounded (R) and show a number of metastatic hallmarks after only seven days of culture on soft substrate (Tang et al., [2010] "Mechanical force affects expression of an in vitro metastasis-like phenotype in HCT-8 cells," Biophysical Journal 99, 2460-2469; Tang et al., [2012a] "Attenuation of cell mechanosensitivity in colon cancer cells during in vitro metastasis," PlosONE 7, e50443). Here, we studied the surface nonspecific adhesion of HCT-8 cells throughout the in vitro metastasis process. A novel bio-MEMS force sensor was used to measure the cell-probe nonspecific adhesion. The adhesion characteristics are analyzed using fracture mechanics theory. Our results indicate that the post-metastatic HCT-8 cells (dissociated R cells) display remarkably diminished surface adhesion and are potentially more invasive than original pre-metastatic HCT-8 cells (E cells). To the best of our knowledge, this is the first report of quantitative data showing the changes in cancer cell adhesion and other cellular mechanical properties during the expression of in vitro metastasis-like phenotype.