More often than not, medical breakthroughs require years--if not decades of arduous research.
Carol Greider, PhD, one of the 2009 winners of the Nobel Prize in Medicine, explained how her years of scientific research may affect our ability to fight life-threatening diseases, such as cancer, and treat age-related illnesses, soon after the award was announced.
The research conducted by Dr. Greider, director of molecular biology and genetics in the Johns Hopkins Institute for Basic Biomedical Sciences, advances our understanding of the intricate functions of human chromosomes. These strands of gene-carrying DNA, which are found in the nucleus of every human cell, control the life-giving processes of cellular division and replication.
In 1984, Dr. Greider played a key role in the discovery of telomerase, an enzyme that maintains the length of structures, known as telomeres, that keep chromosomes intact-much the same way a plastic tip at the end of a shoelace stops it from unraveling. Without telomerase, telomeres would shorten every time a cell divides, leading to the death of the cell.
These discoveries, made by Dr. Greider and two of her colleagues with whom she shared the 2009 Nobel Prize in Medicine, have led to new areas of investigation into controlling cancer (cancer cells may depend on telomerase to divide)...treating age-related diseases (telomeres shorten with age)...and understanding several genetic diseases (caused by dysfunctional telomerase and telomeres).
For insights into the ways that these discoveries may affect human health, Dr. Greider answered these questions…
- Which diseases are believed to be caused by shorter telomeres? Telomerase and telomeres may play a role in several genetic disorders. For example, research at Johns Hopkins has shown that genetic mutations in telomerase may contribute to the development of a progressive and often fatal lung disease called idiopathic pulmonary fibrosis, which afflicts approximately 50,000 Americans.
A similar mutation may cause dyskeratosis congenita, a disorder in which the bone marrow fails to manufacture healthy blood cells, usually leading to severe skin, nail, oral and lung problems and premature aging.
- Why is it important to study these less well-known diseases? Studying patients with telomere-related genetic disorders will help us treat those diseases and understand the consequences of shorter telomere length in everyone. That's important, because there is a wide variability in telomere length among the general population, with many individuals having shorter telomeres.
Research has linked shorter telomere length to an increased risk for coronary artery disease and heart attacks.. and to a shorter life span.
As our scientific and medical understanding of these links increases, shorter telomere length may become a recognized risk factor for a variety of diseases and a target for treatment.
- What, specifically, is the role of telomeres and telomerase in the battle against cancer? In the cancer cell, division and replication is not a healthy, regulated function but an uncontrolled disease.
Scientists think that experimenting with telomerase and telomeres even experimentally shortening telomeres-may have unexpected and positive effects in cancer treatment.
In my laboratory, for example, we bred mice to have nonoperating telomerase and then mated them with mice bred to develop Burkitt's lymphoma, a fast-growing and deadly cancer of the white blood cells.
The first generation of those mice, which developed lymphoma in seven months, had cancer cells containing long telomeres. But by the fifth generation, telomeres in the cancer cells had shortened-and that generation of mice did not develop lymphoma.
Upon investigation, we found that the mice had started to form microtumors in their lymph nodes, but the cancer cells didn't continue to divide.
This study and others have provided the evidence for researchers to begin human trials.
However, cancer is not one disease but many different conditions-and telomerase inhibitors may not work against every cancer.
A recent study in the journal Lancet Oncology showed that lifestyle factors may increase telomerase activity in people with cancer. What can we learn from that research? Elizabeth Blackburn, PhD, with whom I shared the Nobel Prize, participated in research on 30 men with prostate cancer.
It showed that three months of intensive lifestyle changes, such as a low-fat, plant-based diet, moderate exercise, stress management and social support, increased telomerase activity by almost 30% in a type of immune cell. This increases the cell's ability to maintain telomere length, which may provide protection against cancer progression.
Dr. Blackburn and the other researchers note that this was a small study and a preliminary finding and is not evidence that lifestyle changes affect telomerase or that increasing telomerase affects cancer. This interesting study is the basis for future research but not yet applicable for practical recommendations about lifestyle changes and telomerase levels.
- How should people regard supplements or other products that purport to increase telomere length and extend life? At present, there is no scientific evidence showing that any supplement or nutritional factor can reliably increase the length of telomeres. Until such evidence is produced, I think people should be wary of such supplements and products.
