Protein Syntheses in Epithelial-mesenchyme Transitions as Markers of Platelet-induced Cultured Cancer Cell Proliferation

Aims: To study the changes in protein content and protein patterns in platelet activated epithelial-mesenchymal transition of cultured colon cancer cells.

Place and Duration of Study: UT McGovern Medical School, Houston, Texas, USA. Between May, 2015 and May, 2017.

Methodology: Mouse platelets were added to cultured colon cancer cells and fluorescence deconvolution microscopy was performed with image acquisitions being stacked, volume rendered and modeled to yield protein localizations, quantity and patterns.

Results: Studies identified and localized proteins involved in cell transitions. Co-culturing resulted in an increased cell number, increased cell size and increased protein content. Fibronectin content was increased to a greater extent than laminin; G-actin content was also increased indicating up-regulation of synthesis, and the fibroblastic-type cells were much longer with the fibronectin containing fibrillar extensions suggesting increased adhesion was occurring. Greater fibronectin than laminin synthesis indicates cells undergoing a change to matrix protein form rather than a basement membrane, polarized epithelial cell type, observations which suggest platelet activation endows the cells with adhesion and invasion abilities.

Conclusions: The study showed that platelet activation of cancer cells drives endothelial cells into a matrix-compatible mesenchymal form and that the epithelial to mesenchymal transition occurs when surface cells lose polarity and cell-cell adhesion properties. These cells become migratory and invasive for rapid and facilitated cancer progression, due to enhanced adhesion and synthesis of specific proteins and cell extensions.