An entirely new type of physics has been revealed by the metastasis of tumors and other growing tissues. Living cells switch to 3D blobs from 2D sheets by a process called “active wetting” which helps in explaining the reason and mechanism of cancer dissemination. Xavier Trepat and Carlos Pérez-González stated that a new treatment could be designed to avoid cancer metastasis if these forces could be selectively modified in a real tumor for which active wetting must be deeply investigated.
E-cadherin is a protein that provides adhesion between cells and regulates tension within tissues. In order to analyze this phenomenon, human breast cancer cells were used in a laboratory dish. The tension got really high within the tissue resulting in detachment from the collagen-coated gel used as a substrate.
The active wetting was compared with the behavior of passive fluids in which the fluid dynamics is dictated by the Navier-Stokes equations. The transition from 3D spheroid to a 2D sheet is called wetting and the opposite is called dewetting. Scientists observed that the cancer cells did not behave like regular passive fluids in wetting and dewetting. They behave like active fluids depending on cell-cell forces and forces that attach the cell to the substrate.
Active wetting transition allows the cells to go from a contained spherical to a spreading sheet indicating the metastasis of a tumor. These results help in understanding the forces important for cancer invasion. This work needs to be implemented on living tissue and real tumors instead of lab dishes. Two researchers, Richard Morris, and Alpha Yap believed that it is hard to fit biological systems into classical physics frameworks, but the current study is a significant step for making physics relevant to problems of biology.