On DNA Damage, Nobels, Elephants and Cancer

The Nobel Prize in Chemistry 2015 was awarded for DNA Damage repair mechanisms. DNA what??

  • Our DNA has to faithfully produce copies of itself over and over and over again when cells divide. This occurs throughout life and requires incredible fidelity to reproduce DNA that looks exactly the same every time. On top of this, our DNA gets damaged continuously in different ways- such as exposure to radiation. This can lead to mistakes (mutations) in the DNA and consequently affect the products downstream (such as enzymes, structural proteins, chemical messengers) if not corrected. Mistakes in the DNA can lead to cell death or cancer if not checked in time. Luckily, our cells have a hard-working surveillance and proofreading system that constantly checks all our DNA for any breaks or errors and recruits a team to either repair it, or proceed to destroy the cell. Sometimes, the machinery fails, gets overwhelmed, is faulty… and the consequence can be rogue cells that no longer listen to the surveillance team.. that carry on with a different plan.. that can even become cancerous…
  • The Nobel Prize in Chemistry was announced this week.  A nice writeup in fairly simple language on the work and lives of the three investigators is available at the Nobel Prize website. There, they state simply that:”Our DNA remains astonishingly intact, year after year, due to a host of molecular repair mechanisms: a swarm of proteins that monitor the genes. They continually proof-read the genome and repair any damage that has occurred. The Nobel Prize in Chemistry 2015 is awarded to Tomas Lindahl, Paul Modrich and Aziz Sancar for having mapped these fundamental processes at the molecular level. Their systematic work has made a decisive contribution to the understanding of how the living cell functions, as well as providing knowledge about the molecular causes of several hereditary diseases and about mechanisms behind both cancer development and aging.”
  • Newspapers also reported a cool story this week about Elephants being free of cancer. How is that possible? Well, going back to the surveillance team that looks at DNA and makes sure all is well, one particular member was given a lot of fame back in the ’90s. P53, which is the product of the gene TP53, was named molecule of the year by the Journal Science in 1993, and was considered a magic bullet of sorts (TIME has a good article on it from 2001). For those of us who began our foray into science at that time, this was one of the important players that shaped our thinking. This little guy acts as the guardian of the cell’s DNA, ensuring there are no mistakes. This P53 guy is an important one with veto power and sends the cell to its’ death if all “i”‘s are not dotted and “t”‘s are not crossed. So elephants do not get cancer, it seems, due to 20 copies of the TP53 gene, all scattered around their genome, so they have much much more P53 (we only have one copy in our genome) than humans. IMG_3397In a recent study reported in the Journal of the American Medical Association partially funded by the Ringling Bros Circus’ Center for Elephant Conservation (this is crossover science at its’ very best), investigators found that these large numbers  of P53 served to send the cells to their death… that is, they made cells self-destruct if there were any mistakes in the DNA. Hence… cancer would be averted! Yay! It may be an oversimplification, or truly a confirmation that this is a magic bullet. More questions, more intrigue, more fun science. Take a look at this video: https://youtu.be/A60rXVAUKRY.
  • Next week we will look at genetic and environmental factors in aging, cancer and age-associated diseases….

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