Recognition Imaging of Trace E-cadherins on the Bladder Cancer Cells Surface during Epithelial-Mesenchymal Transition by Force-Distance Curve-Based AFM.

Tumor-associated epithelial-mesenchymal transition (EMT) contains a set of transitional cellular states usually judged by the EMT marker expression. E-cadherin is a down-regulated EMT epithelial marker, and the detection of E-cadherin is challenging on cancer cell surfaces in the middle and late stages of EMT. Here, the trace E-cadherins on the living bladder cancer T24 cell surface during EMT were investigated with force-distance curve-based atomic force microscopy. The results confirmed that T24 cells are still in an intermediate state and can be transferred into the mesenchymal phenotype by long-term TGF-β1 induction. During EMT, E-cadherins on the T24 cell surface gradually decreased and rarely clustered. E-cadherin is not completely missing, even at the end of EMT, but is too sparse to cluster. This work provides us with a visual understanding of the expression and distribution of trace markers during EMT and a deep comprehension of the indispensable significance of E-cadherin in cancer cells.