University of Pittsburgh researchers have devised a three-dimensional system in laboratory culture that mimics the growth patterns of colon cancer stem cells in patients. Their findings were presented at the American Association for Cancer Research special conference on Colorectal Cancer: Biology to Therapy, held Oct. 27-30, 2010.

The assay, which uses green fluorescent "reporter" proteins to watch the process of stem cell differentiation, is designed to understand how these cancer stem cells behave, and to identify and test therapies that could halt production of the endless generations of new cancer stem cells that continually revive a tumor.

"Colon cancer stem cells are thought to be the root of therapy resistance, metastases and recurrence in colon cancer, so our approach is to find a way to remove the ability of these stem cells to self-renew," said the study's lead investigator, Julie Chandler, a graduate student in pathology.

"While many labs have investigated notch inhibitors and others have investigated cancer stem cells, our unique approach combines both in a three-dimensional culture that mimics what happens in patients," she said. Animal models, which are immunodeficient and use human xenografs, may not provide accurate information about colon cancer stem cell behavior, Chandler added.

Colon cancer stem cells have the ability to repopulate a tumor after treatment, using stem cells that are resistant to treatment. Such treatment forces a response in these cells, which are genetically unstable, forcing the cells to adapt and pass on resistance to daughter stem cells.