Gerold, Hartman, Lindbloom Gut Microbiota and Cancer

Gerold, Hartman, Lindbloom Gut Microbiota and Cancer

Presentation for Biology: The Gut Microbiota

Doctor 1: Hello. As we move forward with your cancer treatment, we’d like to discuss a little bit about the gut microbiota and how it can influence cancer.

Patient: The gut microbiota? I’ve heard about that, but I didn’t know it played a role in my cancer treatment. What does it have to do with cancer treatment?

Doctor 2: Well, the gut microbiota contains tens of trillions of bacteria. It is even considered another organ with an important role to play in your cancer treatment and overall health. Researchers are beginning to understand this and you could be a patient in this study.

Patient: Wow! That's really neat. I didn’t know the gut microbiota was so important. I’m willing to try anything so I’d definitely like to be apart of this study

Doctor 1: That's wonderful. With new studies, we can expand our knowledge to treat even more people! We are realizing that there are new ways to treat cancer and improve the current cancer treatment methods using the gut microbiota.

Doctor 2: For your cancer diagnosis, we mainly want to discuss the linkage between gut microbiota and improved cancer treatment. We’ll put you on CTLA-4 blockade and cyclophosphamide or CTX as its commonly called, treatments. Don’t worry, they aren’t as complicated as they sound.

Doctor 1: The gut microbiota could improve diarrhea, a common side effect of Irinotecan. This will help improve the quality of life during chemotherapy treatments.

Patient: All of that sounds great, but I’m still not really sure what it does. I know I'll be taking Irinotecan during my treatment, and a friend of mine who had cancer suffered terrible stomach symptoms while on it. I would love to not experience that. Since I’m also taking CTX, a common chemo drug, is there a correlation between CTX and the gut microbiota?

Doctor 2: That's a lot to answer, and while there’s no definitive answer, research is showing that the gut microbiota could potentially help with all the topics we've mentioned. That’s what makes studies like in which you are participating so important.

Doctor 1: Well, let’s start with CTLA 4 and CTLA 4 blockade.

Patient: Okay so what’s that?

Doctor 2: CTLA 4 prevents T cells from working, cells that could be helping to fight cancer. So CTLA-4 blockade makes sure that T-cells CAN work. This is often done with a drug called Ipilimumab.

Patient: So basically we want to ensure that my T-cells are not blocked because if they are then they won’t’ fight against the cancer cells in my body?

Doctor 1: Exactly! Researchers found that of mice from different environments, those with a certain gut microbiota were better able to combat tumor growth when injected with cancerous growths.

Patient: So how did researchers determine that the gut microbiota was playing an important role in this process? It could have been chance that caused one population of mice to have fewer cancerous growths.

Doctor 2: That's an excellent question. The two groups of mice, we’ll say group A and B, were both injected with melanoma growths. Researchers saw that tumors grew faster in the group A mice. The group A mice demonstrated an increased immune response due to tumor specific T cells. When fecal matter from group A mice was transferred to group B mice, tumor growth was delayed. This indicates that gut microbiota play a role in preventing tumors.

Patient: That's an odd method, but I guess I can understand it. If the gut microbiota is as important as you doctors say, it makes sense that microbes could play an important role in my health. I know I’m taking the chemo drug CTX. You mentioned that my gut microbiota might play a role in how effective CTX is at treating my cancer.

Doctor 1: You're exactly right. CTX works by damaging the mucosal layer of the gut, which allows the gut microbiota to move deeper into the gut and further in towards the spleen and lymph nodes. There is stimulation of the helper T cells to secrete a component, cytokine, which is able to attack the cancerous cells by damaging its DNA and making replication impossible. Without the gut microbiota stimulating the process, cancer cell death would not be possible.

Doctor 2: We have found that bacteria in the Lactobacillus family are perhaps the most important bacteria present in correlation to treatment with CTX. And, when mice were treated with antibiotics, killing the gut microbiota, the treatment was much less effective.

Patient: I guess I need to start eating more ice cream! Although, I'm lactose intolerant so that might not be the best idea. However, I know that I’ll be taking Irinotecan in combination with my chemotherapy treatment. It’s a common drug used with chemo, but the side effects are terrible. My friend that was treated with Irinotecan suffered terrible diarrhea and was even hospitalized for a while.

Doctor 1: I see your concern. There can definitely be complications with Irinotecan. But again, the gut microbiota might be able to help. When mice had Beta-glucuronidase, a component of certain bacterias such as E. coli, blocked there was an alleviation of the toxic effects of Irinotecan without harming other cells.

Patient: Is this something that could happen to me? Could the stopping of certain bacteria prevent diarrhea?

Doctor 2: Unfortunately, we don't understand all the basics yet, so the short answer is no. The long answer is that we are hoping to eventually be able to take this technology and improve the interactions with the gut microbiota.

Patient: I hope it is available soon because it appears to have a lot of potential.

Doctor 1: It really does. We are looking at cases where the gut microbiota could play a critical role in helping to alleviate the side effects associated with chemotherapy.

Doctor 2: One such way the gut microbiota could do this is through the release of gut microbiota-dependent helper T-cells. They intervene and restore balance in the intestines after damage caused by chemo.

Doctor 1: We have a long way to go before we fully understand how the gut microbiota stimulates T-cells and their processes.

Patient: This has truly been fascinating. Thank you for all your time and information. I learned a lot of new stuff today.

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