Researchers led by Dr. Robert A. Weinberg of the Whitehead Institute for Biomedical Research have made the first genetically defined human cancer cells, according to a report published in the July 29 issue of Nature. This achievement brings scientists one step closer to understanding the complex process by which human cells become cancerous.
The genetically defined tumor cells will give scientists an important new window on the biochemical and physiologic changes involved in the development of human cancer, Dr. Weinberg says. They promise to be particularly useful for exploring the later changes in tumor development including the genetic changes that lead to metastatic disease, a problem that has been difficult to study in the past.
The conversion of normal cells into tumor cells involves changes in the activity of a number of distinct different genes and proteins in a cell. Although scientists have been able to transform normal mouse cells into tumor-forming cells by introducing several cooperating oncogenes (cancer-causing genes) into these cells, human cells have been resistant to such transformation.
"We wondered what it was about the mouse cells that made them so easy to transform and hypothesized that it might have something to do with the presence of the enzyme telomerase," says Dr. William C. Hahn, a postdoctoral fellow in the Weinberg laboratory. Dr. Hahn and Dr. Christopher M. Counter, a former Whitehead postdoctoral fellow now at Duke University Medical Center, are the lead authors on the Nature paper.
Two years ago, Dr. Weinberg's group and others identified the gene that codes
for the key component of human telomerase, an enzyme that prevents the natural
shortening of chromosomes during cell division. When the telomerase gene is
switched on, cells continue to grow and divide indefinitely. Such rampant,
unchecked cell growth is characteristic of cancer, says Dr. Hahn, who is also an
oncologist at the Dana-Farber Cancer Insti
Contact: Stefanie Doebler
Whitehead Institute for Biomedical Research