Telomeres are the caps at the end of each strand of DNA that protect our chromosomes, much like the plastic tips at the end of shoelaces. Without the coating, shoelaces become frayed until they can no longer do their job, just as without telomeres, DNA strands become damaged and our cells can’t do their job.
Telomere dysfunction is a critical aspect of aging and cancer. As cells divide, telomeres shorten. Eventually, they become so short that they trigger a mechanism within the cell that prevents further cell division, known as “replicative senescence.” This is thought to be a major cause of aging.
If telomeres become critically short and the cell does not enter senescence or die (apoptosis), it might continue to divide, leading to genomic instability, a hallmark of cancer. The cell’s DNA can start to fuse together, leading to mutations and further increasing the risk of cancer.
In addition to natural aging, several factors can contribute to telomere shortening and dysfunction, including oxidative stress, inflammation, and certain genetic disorders. Telomere dysfunction can also lead to various human diseases, including cardiovascular diseases, diabetes, neurodegenerative diseases, and certain types of cancer.
Interestingly, some types of cells, like germ cells and cancer cells, express an enzyme called telomerase, which can add DNA to the ends of telomeres, effectively making them longer and allowing the cell to divide indefinitely. This is why these types of cells can divide so many times. However, most normal somatic (body) cells do not express telomerase, leading to telomere shortening over time.
There is considerable interest in understanding telomere biology and finding ways to address telomere dysfunction in the context of disease. Some experimental approaches involve using telomerase to extend the lifespan of healthy cells, while others involve inhibiting telomerase in cancer cells to limit their ability to divide. However, these are still areas of active research and have not yet led to widely available treatments.
