The University of Illinois study reveals that cancerous tumors only have a few cells that are able to break ay and spread, but the curve along the edge of the tumor may play a large role in activating these tumor-seeding cells. Various shapes and patterns of engineered tissue environments were used in a study of skin cancer and found the more curved the cell cultures were, the more cancer cells at the edges displaying markers of stem cell characteristics and the key to spreading to other tissues.
A professor of materials science and engineering, Kristopher Killian, along with Timothy Fan, a professor of veterinary medicine, are the researchers who published their findings in the journal Nature Materials. Killian said that the most dangerous part of cancer is metastasis. Some cancer stem cells adopt deadly characteristics where they travel through the bloodstream to other tissue and form new tumors. These cancer stem cells are resistant to chemotherapy drugs and the cancer comes back.
Specializing in tissue engineering to create models of tumors, Killian’s group more accurately studied cancer processes in a culture dish using mouse skincancer colonies on various 2D and 3D environments of different shapes and patterns to see if the shape contributes to activation of cancer stem cells and where in the tumor the stem cells appear. It was found that cancer stem cells seemed to appear in the highest numbers along the edges of the engineered tumor environment, especially corners and convex curves. Normal stem cells usually prefer a soft, squishy, internal position, so everyone had assumed the cancer stem cells were in the middle of the tumor. They also found the geometric constraints, as where a tumor touches healthy tissue, seems to activate these cancer stem cells at the perimeter.
A number of tests confirm tumorspreading ability such as genetic analysis. Other cancer lines tested were human cervical, lung and prostate, and found they responded to the patterned tumor environments in the same way.
More mice developed tumors when given the cells they had engineered to have these stem cell characteristics, and had a higher incidence of metastasis in the lungs. Regions that develop these kinds of shapes may activate cells that can then escape and form more tumors. Their hopes are that the patterned, engineered tissue environments will give researchers a new way to find and culture cancer stem cells.
–Dr Fredda Branyon