LA JOLLA, CA-A close collaboration between researchers at the Salk Institute for Biological Studies and the Institute for Advanced Study found that the tumor suppressor p53, long thought of as the "Guardian of the Genome," may do more than thwart cancer-causing mutations. It may also prevent established cancer cells from sliding toward a more aggressive, stem-like state by serving as a "Guardian against Genome Reprogramming."
The new work, reported by Geoffrey M. Wahl, Ph.D., and Benjamin Spike, Ph.D., at Salk Institute and Arnold J. Levine, Ph.D., and Hideaki Mizuno, Ph.D., at IAS, Princeton, in this week's online edition of the Proceedings of the National Academy of Sciences, revealed striking parallels between the increased reprogramming efficiency of normal adult cells lacking p53, the inherent plasticity and tumorigenicity of stem cells, and the high incidence of p53 mutations in malignant cancers.
"A poorly differentiated appearance, cellular and genetic heterogeneity are well-known hallmarks of many aggressive and deadly cancers," explains Wahl, a professor in the Gene Expression Laboratory at Salk, "and it has recently been suggested that these properties result from the presence of stem-like cancer cells. Our findings indicate that p53 mutations could allow cells within a tumor to turn back time by acquiring a stem cell-like 'program.'"
Cancer cells need to acquire some of the characteristics of stem cells to survive and adapt to ever-changing environments. These include immortality, the ability to self-renew and the capacity to produce progenitors that differentiate into other cell types. "Each tumor represents a diverse collection of cancer cells," says Wahl, "and the question was how best to explain how such heterogeneity arises."
In the past, the cellular diversity of cancers has mostly been attributed to genetic instability, which many years ago Wahl and his team showed to occur when p53 is disabled. As
|Contact: Gina Kirchweger|