January 22, 2016
Brady scientist Alan Meeker, Ph.D., is one of the foremost experts on a tiny but very complicated subject: telomeres. These are bits of specialized DNA found at the ends of every chromosome. They are like little shields, tips that protect the chromosome from wear and tear — think of an aglet on a shoelace, keeping the strings from fraying. Every time a cell divides, we lose a minuscule portion of the telomere's DNA; as we age, our telomeres get progressively shorter. They're a buffer between our chromosomes and the outside world, and as they shrink, we become more vulnerable to illness. Back in 2009, Discovery reported on Meeker's discovery with Brady scientist Donald Coffey, Ph.D., The Catherine Iola and J. Smith Michael Distinguished Professor of Urology, that the shortening of telomeres is an important contributing factor to the development of prostate cancer, and that men who inherit short telomeres have a higher risk of developing cancer.
Since then, Meeker has continued to work with Hopkins scientists to learn more about telomeres, and with Christopher Heaphy, Ph.D., he found that, in men who underwent radical prostatectomy, those with telomere abnormalities in both their prostate cancer cells and in nearby cells that otherwise appeared normal "had a 14-fold increased risk of dying from their disease."
Next, "given these interesting results, particularly the presence of short telomeres in the nearby normal-appearing cells, we hypothesized that the presence of shorter telomeres in diagnostic biopsies would also be associated with risk of prostate cancer." In collaboration with colleagues at the Johns Hopkins Bloomberg School of Public Health, Meeker and Heaphy studied telomeres in normal cells in biopsies from men who received a placebo in a national prostate cancer prevention study, the Prostate Cancer Prevention Trial.
"We found that men with short telomere lengths in their biopsies had a higher likelihood of having prostate cancer compared to men who had normal telomere lengths," says Meeker. These findings suggest that telomere shortening in normal-appearing cells may help predict the presence of prostate cancer. "In order to test this idea, we are validating these findings, and also performing studies to better understand the biology of this subset of cells with short telomeres within the prostate tumor microenvironment." This work was recently published in the journal, The Prostate.