April 27 : Cancer researchers at Ontario Cancer Institute (OCI) have developed a method to convert normal human blood cells into ‘human’ leukaemia stem cells.

The converted cells, when transplanted into special mice that permit the growth of human cells, can replicate the entire disease process from the very moment it begins.

“Most human leukaemia research involves studying a patient’s diseased cells or a cell line grown from those cells. However, since cancer takes many months or years to develop, just studying the cells at the end of the process does not let you know what the series of changes were that caused the cells to become leukaemic, and when they happened,” said Dr. John Dick, Senior Scientist at OCI, the research arm of Princess Margaret Hospital, and a Professor in the Department of Molecular Genetics, University of Toronto.

“With the method we developed, we have duplicated the natural process every step of the way. The method we developed opens the pathway generally to understanding the process of how cancer begins,” he added.

The scientific team of Frederic Barabe, James Kennedy and Kristin Hope introduced a specific leukaemia gene into normal human stem cells and injected the genetically altered cells into mice that lacked immune systems. The result? 100% of the mice developed fatal leukaemia that displayed the same characteristics and patterns of human disease.

For the past 20 years, said Dr. Dick, leukaemia research has focused mainly on human cells where the disease already exists or by studying leukaemia created in mouse cells. This study flipped it around to focus on asking which are the normal cells within which the disease arises and then how it evolves and progresses, all within the context of human cells.

“So what we are building is a new approach and way of studying how leukaemia arises in the first place. We found that with the leukaemia gene we were using, the disease only arose from immature stem and progenitor cells. The leukaemic stem cells that were created seemed to change as the human leukaemia was grown for longer times in a series of transplanted mice. Our findings of how these leukaemic stem cells functioned could explain several features of the leukaemia in children and adults that also contain the same leukaemia gene, MLL-ENL,” Dick said. The findings are published in the journal Science. (ANI)