Cell Structure Helps Direct Cancer Gene 'Switch'

WEDNESDAY, Nov. 14 (HealthDay News) -- U.S. scientists say they have uncovered a biological "switch" for key genes in cancer cells.

They found that genes in cancer cells are silenced by distinct changes in the density of structures called nucleosomes within the cells.

"The study shows for the first time exactly how genes get shut down in cancer cells. It identifies what the target looks like, so that new therapies can be designed to turn them back on," study lead author Peter A. Jones, director of the USC/Norris Comprehensive Cancer Center and Distinguished Professor at the Keck School of Medicine of USC, said in a prepared statement.

According to a statement from the university, "The study showed that silencing of transcription start sites in some cancer cells involves distinct changes in nucleosomal occupancy -- or the density of nucleosomes -- in the cell."

A process called "DNA cytosine methylation -- the addition of a group of specific chemicals to a stretch of DNA that can lock or silence a gene -- may ultimately lead to [gene] silencing by enabling the stable presence of nucleosomes at the start sites of cancer-related genes," the release said.

The study was published in the Nov. 13 issue of the journal Cancer Cell.