Prostate Cancer Epithelial Mesenchymal Transition by TGF-β1 exposure monitored with a Photonic Crystal Biosensor

摘要

During prostate cancer progression, cancerous epithelial cells can undergo epithelial-mesenchymal transition (EMT).EMT is a crucial mechanism for the invasion and metastasis of epithelial tumors characterized by the loss of cell-celladhesion and increased cell mobility. It is associated with biochemical changes such as epithelial cell markers Ecadherinand occludins being down-regulated, and mesenchymal markers vimentin and N-cadherin being upregulated.These changes in protein expression, specifically in the cell membrane, may be monitored via biophysicalprinciples, such as changes in the refractive index (RI) of the cell membrane. In our previous research, wedemonstrated the feasibility of using cellular RI as a unique contrast parameter to accomplish label-free detection ofprostate cancer cells. In this paper, we report the use of our Photonic-Crystal biosensor in a Total-Internal-Reflection(PC-TIR) configuration to construct a label-free biosensing system, which allows for ultra-sensitive quantification ofthe changes in cellular RI due to EMT. We induced prostate cancer cells to undergo EMT by exposing these cells tosoluble Transforming Growth Factor Beta 1 (TGF-β1). The biophysical characteristics of the cellular RI werequantified extensively in comparison to non-induced cancer cells. Our study shows promising clinical potential inutilizing the PC-TIR biosensing system not only to detect prostate cancer cells, but also to evaluate changes in prostatecancer cells due to EMT.