"The quantifiable biomarkers we've characterized could be useful for monitoring laboratory-simulated ageing as well as potential drugs or therapies that alter the ageing process”, said James Sligh Jr., M.D., Ph.D., assistant professor of Medicine and Cell & Developmental Biology.
The new biomarkers are changes to the DNA of mitochondria. Those cellular organelles manufacture energy in the form of the molecule ATP. Energy generation includes, as a by-product, the production of reactive oxygen species, which can damage the DNA present in mitochondria. Some theories of cellular ageing centre on mitochondria and decreased energetic capacity resulting from mitochondrial DNA mutations. In addition, mutations in mitochondrial DNA have been associated with tumour development.
"We initiated this project with the idea that perhaps there was a specific mitochondrial DNA deletion signature that would be associated with tumour development in the skin," Sligh said. The researcherswere surprised to find in skin samples from patients having non-melanoma skin cancer removed a panel of mitochondrial DNA deletions in the tumour-free skin that was adjacent to the tumours, but not in the tumours themselves.
The mitochondrial DNA mutations in the tumour-free skin correlated with the ageing process. The newly identified deletion mutations will now go into "Mitomap," a database of all known human mitochondrial genome changes. "Unraveling the molecular clues as to why ageing cells function differently than young cells requires that we have molecular markers that we can track," Sligh said.
The newly identified biomarkers will provide another tool for studying mitochondrial damage that contributes to ageing and cancer, and for screening compounds that prevent or reverse the process, Sligh said.
MEDICA.de; Source: Vanderbilt University Medical Center