Figure 4. Morphological changes and immunostaining evidences suggested that EMT is involved in the process. (A–C) HT-29 cells were exposed to 0 or 15 nM of arsenic for 0, 30, or 60 passages and typical images with or without AS treatment are shown. Note the morphological shift of HT-29 cells from epithelial-like to mesenchymal-like morphology; Arrows in (A–C) point to the cells with typical morphology. Bars = 100 μm. (D) Relative adhesion ability of HT-29 cells exposed to AS for 0, 30, or 60 passages; *P < 0.05; **P < 0.01. Immuofluorescence staining of E-cadherin (E–M) and vimentin (N–V) in HT-29 cells for the indicated times. (E, H, and K) are green channel that represent E-cadherin staining, and (N, Q, and T) are green channel that represent vimentin staining. (F, I, and L) are blue channel of (E, H, and K), and (O, R, and U) are blue channel of (N, Q, and T), that represents nuclear DNA staining by DAPI, respectively. (G, J, M, P, S, and V) represent merged images; bars = 100 μm.