Fixing DNA with Broccoli

A new study published in the Proceedings of the National Academy of Sciences last week has found that 3,3’-diindolylmethane, or DIM, is a strong combatant of radiation damage, on top of its previously established ability to help prevent cancer. DIM was found to activate ataxia-telangiectasia mutated, or ATM, a molecule found in the nucleus that controls DNA repair processes. When activated with DIM, ATM significantly increased survival rates in rats exposed to full-body irradiation.

Image
This is what DNA repair looks like…probably. (Source: en.wikipedia.org)

DIM has kind of an odd back-story to it. I’ll go ahead and tell you, it involves broccoli, and I’m no happier about that than you are. Cruciferous vegetables, like broccoli, have already been linked to reduced risk in a number of human cancers and one particular component of your everyday cauliflower or bok choy has been found to prevent tumors in animals. That component is indole-3-carbinol, or I3C. When you eat your cabbage or Brussels sprouts, for whatever reason you may, your stomach breaks down I3C into a number of different compounds, one of which is DIM.  DIM is already being studied as a possible precautionary medicine for cancer, but this study found it carries a heck of an added benefit.

Image
A cruciferous family reunion (source: http://www.diagnosisdiet.com)

Using rats, the group found that injections of DIM beginning up to 24 hours after full-body irradiation could significantly extend life expectancy. Those rats that began their DIM injections 24 hours after irradiation saw a much smaller increase, with around 30% of those rats surviving to 30 days. For those that began their treatment regimen either 10 minutes or 2 hours after irradiation, there was a much larger increase, with 50% and 60% of rats respectively surviving to the 30 day mark. The group also found that these DIM injections did not affect tumor growth with or without irradiation, meaning that the treatment would protect healthy host cells while still allowing radiation to destroy cancer cells.

So how does DIM manage this? Well, in a healthy cell DIM activates that ataxia-telangiectasia mutated I mentioned earlier, which helps to fix damaged DNA. ATM phosphorylates (i.e. adds a phosphate group to) several proteins that help to stop the cell cycle and initiate DNA repair or lead to apoptosis (programmed cell death, if the damage is too extensive). In a cancerous cell, some portion of this pathway is defective and so ATM activation doesn’t end up conferring any of its restorative effects. Instead, these cancerous cells remain vulnerable to the damages of radiation while healthy cells get primed for intense DNA repair. Once DIM manages to find its way into clinical use, which could be a ways off, it will hopefully be able to make the process of radiation a smoother one, alleviating symptoms and making cancer treatment a much less debilitating experience.

Lastly, I hate to say it, but yeah, you should probably eat more broccoli. It seems overwhelmingly good for you. You win this one childhood authority figures.

Original article: http://www.pnas.org/content/110/46/18650.full

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s