Cold Spring Harbor, NY A team of researchers at Cold Spring Harbor Laboratory (CSHL) has identified a leukemia-specific stretch of DNA called an enhancer element that enables cancerous blood cells to proliferate in Acute Myeloid Leukemia (AML), a devastating cancer that is incurable in 70% of patients. Just as important, the findings offer a mechanistic insight into how a new class of promising drugs one version of which is already in human clinical trials appears to halt the growth of cancer cells so effectively.
The research, appearing today in Genes & Development and led by CSHL Assistant Professor Chris Vakoc, centers on the way a cancer-promoting gene is controlled. When this oncogene, called Myc, is robustly expressed, it instructs cells to manufacture proteins that contribute to the uncontrolled growth that is cancer's hallmark. The Myc oncogene is also implicated in many other cancer types, adding to the significance of the new finding.
Vakoc's team discovered an enhancer element that controls the Myc oncogene specifically in leukemia cells. Unlike many other DNA-based gene regulators, this string of DNA "letters" is nowhere near the Myc gene it regulates. In fact, it's far away, and in order to affect the Myc gene, some other element unknown, prior to these experiments -- has to bring the enhancer in proximity to the gene. In their experiments, the team found a protein complex, called SWI/SNF, that links the enhancer element and the Myc gene it activates.
"The enhancer elements we discovered are 1.7 million DNA bases away from their target gene, Myc," says Vakoc. "But we were able to show that this long stretch of the genome is bent and looped in the cell nucleus in such a way that the remote enhancer segment literally touches the distant segment harboring the cancer gene. Our results suggest that this regulatory conformation fuels the uncontrolled growth of cancer cells and may explain why the Myc g
|Contact: Jaclyn Jansen|
Cold Spring Harbor Laboratory