Telomere and cancer

IstockPhoto

Telomere and cancer

Author: Reilika Nestor 06.01.2015 at 00:00

Scientists now believe they’ve discovered the “key” to rewind this clock and stop us from aging. This key lies in the enzyme telomerase. Telomeres are regions of our DNA chains located at the ends of chromosomes. The purpose of telomeres is to protect the ends of chromosomes from damage. 

But this isn’t as straightforward as one might think. The same enzyme that rejuvenates our cells can kill them. This enzyme feeds cancer much as it feeds cells. Cancer cells are healthy cells that have gone astray. Their success depends on telomerase. If the ends of DNA become too short, the cell doesn’t divide and eventually dies. Sometimes, instead of dying a cell will undergo changes that turn it to a cancer cell. One of these changes is activation of telomerase which allows endless division making the cancer cell immortal. 90% of cancer cells show hyperactive telomerase. This can be compared with giving a gun to a person. In the hands of a stable person the gun presents little if no danger, but if the bearer turns out to be a psychopath, it automatically becomes a threat. The same applies to regular and cancerous cells. The latter are unstable which is why they shouldn’t be stimulated but suppressed.

This has been tried in San Francisco. Liz Blackburn and her lab team gave cancer cells faulty telomeres. Within a week the cancerous cells became extremely “unhappy” with the situation. Figuratively speaking, the cancer cells hated their life so much they committed suicide. And this is great win for a cancer patient.

Although some cancer cells have found new ways for producing telomeres, this area of study hasn’t been abandoned and is in continuous development. If you leave cancer without its fuel, it’s forced to come to a still.

Ironically, the deadly success of cancer explains aging too. In a way, aging can be seen as protection from cancer that is almost certain to accompany the long lives we've grown accustomed to. Suppression of telomeres, depriving cells of immortality, and supplying cells with limitless amounts of fuel helped in avoiding cancer and gives us our modern life expectancy. By increasing our lifespan or lengthening telomerase we also increase the likelihood of developing cancer. This is why we need to find a balance between longer lives and the risk of cancer.

Dr Mary Armanios is a medical doctor and scientist who is convinced in the existence of a classical aging syndrome which may not be manifested in the face. For example, the story of a boy about to turn 17 who had the internal organs of an 85-year-old. When the DNA of this boy was thoroughly examined, scientists found a mutation that had corrupted his telomerase: he didn’t have two healthy genes from both of his parents but only one. For this reason, his bone marrow could be compared to that of a 100-year-old. Dr Armanios found a similar genetic defect in several lung diseases. This proved that people with telomerase disturbances have a higher predisposition for idiopathic pulmonary fibrosis. A whole new window for us, as this shows how telomerase affects more diseases than thought earlier. The shorter telomeres are, the higher the risk of developing cardiovascular disease, diabetes, and – as we know now – cancer.

The length of telomerase hasn’t been carved in stone but varies and can be stretched. Lifestyle plays a large role in this and constant stress can have a devastating effect in health. Psychologist Elissa Epel joined Liz Blackburn to study chronic stress and to measure stress-levels in human cells. They were keen to find out whether stress actually causes widespread change in cells of a healthy person and if such stress-related damages could be seen in the body. People with a lot of unavoidable stress were gathered as study subjects and it turned out that such people die younger. When they compared telomeres of women under constant acute stress with those of stress-free women, they discovered something extraordinary: the cells of stressed women were a staggering 17 years older.

Telomeres can be considered a warning system or signal of biological aging. Of course, the most important question here is whether damage can be undone. One male-based study showed it can. Men with prostate cancer tried changes in lifestyle instead of undergoing surgery. They learned to relax, train themselves, they gave up greasy foods and got counseling. After three months of testing, this change in patterns had a positive effect on 500 genes. This study was initiated by Liz Blackburn and Dean Ornish. They also kept an eye on the telomerase levels of the men and discovered a 30% increase after three months. This means that already in 90 days, men aged 29% less. The increased telomerase can also be linked to the development of cancer, but this study did not show a negative correlation. On the contrary, their cancer was relieved and their genes became stronger. One of the subjects was not completely free from cancer, but his biopsies did turn out negative.  

Medication costs millions, but it’s amazing how much we can change in the world with our attitude completely free. Exercise and positive thinking changes the length of telomeres. You stretch your telomeres by lowering your levels of stress. In a quarter of people, telomeres begin to grow within a year or two. If we manage to keep telomeres from shrinking, we are protected from illness associated with old age.


Source:
http://et.wikipedia.org/wiki/Telomeer
(Immortal, USA 2010)
http://etv2.err.ee/videod/dok_film/3643d85e-e2f7-40ba-a240-273b4616427b