Last week’s post looked at telomeres, and how they form the centre of the modern search for a ‘fountain of youth’ (if you don’t know what telomeres are, you should probably check it out first).
As a quick reminder, telomerase is a really cool enzyme that catalyses (speeds up) the process of adding to the telomeres. In humans, telomerase is found largely in our germ cells and and embryonic cells– the reproductive cells, such as sperm and egg so that any offspring have long telomeres to live a full life. (As an interesting aside, Dolly the Sheep died young in part because she was cloned from old cells with shorter telomeres).
In most other cells of the body, telomerase activity is repressed by a specific DNA sequence to prevent the cells from dividing uncontrollably and indefinitely. And cells dividing uncontrollably and indefinitely equals cancer. So if we’re going to exploit telomerase to slow ageing, we’ve got to work out how to save people from any cancers they develop. Alternatively, we could suppress telomerase in cancer cells (as it is normally overactive to promote rapid and indefinite cell replication) as another possible cancer treatment. But it makes it difficult to have a long, cancer-free life!
How can we lengthen telomeres safely?
If our other cancer treatments or preventions become extremely effective, then it is quite plausible that we could simply dose people with telomerase or, more easily, prescribe drugs that promote its activity. Then although the increased telomere length could increase the risks and dangers of cancer, we would be able to treat it as it occurred, or prevent it … who knows what the future holds! But until then, it is quite dangerous to try increasing telomerase activity due to these risk of cancer.
One exciting area of research is also exploring other ways to increase telomere length. Exercise is the magic word coming out of this work. Not only has it been linked to increasing telomere length, but additionally has been shown to have a role in preventing cancer.
This research has suggested that regular exercise may affect telomere length by reducing the length of telomere lost over time. Exercise reduces oxidative stress and chronic inflammation on a biochemical level within your cells. Both oxidative stress and chronic inflammation cause telomeres to become even shorter than they would in a normal replication and increase the rate of ageing based on telomere length.
Excitingly, exercise and this reduction of oxidative stress is also effective in reducing cancer risk, so if you exercise, you’re getting double benefit!
And one last study actually showed an increase in telomerase activity and small reversals in the shortening of telomeres when undertaking endurance training (but, interestingly, the results aren’t seen in resistance training). It’s a smaller study, and doesn’t mention what effect the increased telomerase activity has on cancer, so it’s sure to be an active area of research!
Telomerase and cancer treatment?
Cancer cells almost exclusively have long telomeres and overactive telomerase. This is so the cancer cells can rapidly divide and create unchecked growth (such as tumours). Simple solution: give the patient telomerase-suppressing drugs and the cancer cells will start ageing like every other cell and not be able to create massive tumours … at least not nearly so quickly or successfully.
Such treatments would probably have some effect on ageing, but as they haven’t entered trials in humans yet, it’ll again be a while till we know!