Finding the cancer culprit
Researching the link between chemical exposures and cancer
University of Minnesota researcher Lisa Peterson is studying the relationship between harmful substances like tobacco and cancers
Lisa Peterson, PhD, is a professor and researcher in the Division of Environmental Health Sciences in the School of Public Health at the University of Minnesota. Dr. Peterson’s research focuses on how the chemicals present in tobacco smoke cause cancer.
In this Q&A, Dr. Peterson speaks about her passion for chemistry and biology, her research, and her role in the 10,000 Families Study:
Could you tell us a bit about yourself?
I’ve been faculty at the University of Minnesota for more than 25 years. Before that, I was researching cancer at a non-profit research institute called the American Health Foundation. I am a native Minnesotan. I went to college at Macalester and graduate school at the University of California San Francisco. I did my postdoctoral work at Vanderbilt University in Nashville, then I moved to New York City. I did a loop around the country before coming back to Minnesota, which is my favorite place. I had family in Minnesota and my kids loved it, so I really enjoyed being back.
Can you tell us why you decided to major in chemistry in college and then pursue pharmaceutical chemistry in graduate school?
Chemistry was always a love of mine. In high school, I was really interested in learning the chemical science behind baking. One of my favorite high school chemistry experiments was making peanut brittle.
I was very interested in biology as well. If you’d talked to me in ninth grade, I would have said I wanted to be a horticulturist because I have always loved plants. But in tenth grade, I took a biology class where I learned about mammalian biology and thought it was even more interesting than plant biology.
When I went to college, I majored in chemistry, and while I couldn’t fit in a biology major or minor, I took all the biology classes I could. I like biochemistry and was interested in the interface between biology and chemistry, so that led me to medicinal or pharmaceutical chemistry. I studied drug safety and toxicology in graduate school.
How did your career lead you to focus on cancer and the role of chemical exposures?
I got started on the cancer track as a postdoc at Vanderbilt because I was looking at how chemicals interact with DNA. I got more involved with cancer research at the American Health Foundation and realized that it was the direction that I wanted my career to take. I was very curious about how chemicals in tobacco smoke cause cancer. Understanding how chemicals cause cancer can lead to approaches to prevent cancer.
Tell us about your research on how tobacco smoke causes cancer.
I use a combination of chemistry and biology to understand how chemicals cause cancer. Most of the compounds I’ve studied are in tobacco smoke. I’m researching the very early parts of the cancer process and looking at what is involved and defining the mutations caused by the DNA modifications. DNA is made up of A, C, T, and G bases that pair together in a specific way. Sometimes, chemicals cause the letters to pair wrong and you get a mutation. It’s like when the key on a typewriter gets broken and types the wrong letter and changes the meaning of the sentence. A DNA adduct is formed when a harmful chemical attaches itself to the DNA molecule and mutations or errors in the genetic code can occur. These errors can cause the cell division brakes to not work and the cell division accelerators to be always on, and causing cells to divide out of control, which can lead to cancer. If the cell dies or the damage gets repaired, it doesn’t become a tumor cell. I look at the events leading to the formation of DNA adducts and their repair.
Specifically, one compound I study is called furan, which is present in tobacco smoke, wood smoke, and car exhaust. This compound causes liver cancer in rats and mice when given orally and lung and liver damage when it is inhaled. Future studies will determine if furan contributes to the harmful effects of tobacco smoke in humans.
How much cancer risk is due to personal behavior versus what people are exposed to in their environments that they may not have control over?
A large majority of cancers are traceable to lifestyle behaviors that are modifiable. Tobacco use is associated with many cancers because addiction to nicotine drives exposure to many harmful chemicals. Tobacco smoke has over 70,000 chemicals and more than 70 have been shown to have potential for causing cancer in humans. The lungs are a key target because they get the onslaught of tobacco smoke chemicals, but also other tissues like the bladder, liver, and esophagus are also targets of tobacco chemicals. Another personal behavior that increases cancer risk is drinking alcoholic beverages because alcohol is a carcinogen. Sun exposure is carcinogenic so it’s important to control your sun exposure if possible and wear sunscreen to prevent skin cancer.
However, people don’t always have control over their exposures. It’s been shown that receiving secondhand smoke can expose you to a considerable amount of the harmful chemicals in tobacco smoke. Some of the same chemicals are in air pollution, which is also a lung carcinogen. Radon is another cause of lung cancer in people. That is why it is important to know the radon levels in your home so that you can try to modify your exposure to it.
You are the co-program leader of the Carcinogenesis and Chemoprevention Program in the University of Minnesota Masonic Cancer Center. What is that program and what do you do in your role?
The program is a group of faculty in the Cancer Center who are interested in understanding the exposures and basic biochemical mechanisms that cause cancer. We also look at cancer prevention strategies and how to prevent early lesions from growing into advanced cancer. My job is to foster collaborations, connect people to resources and advance cancer research at the University of Minnesota.
It’s been a fun position because I get to hear about other people’s research, and I enjoy matchmaking and helping people make connections.
What is your role with the 10,000 Families Study (10KFS)?
I’m one of the principal investigators of the cancer cohort grant because of my expertise in toxicology. I lead another team that measures exposures to harmful chemicals in people and interact with a lot of people at the Minnesota Department of Health, so I have a lot of relevant connections that were important for the biomonitoring studies that will be performed in the 10KFS cancer study. I also bring the understanding of how exposures can lead to cancer.
How does 10KFS differ from your other research?
I’ve never been in this kind of study where you recruit people and participants provide biospecimens, so I’m learning a lot. I’m interested in getting participants into 10KFS. I like learning new things and seeing the application of basic research of the type I do to actually help human health. I like being part of this project where we can hopefully connect exposures to cancer risk with the ultimate goal of preventing cancer. Cancer can sometimes be cured, but the best cure is prevention.
What are your recommendations for people who want to get exposed to or pursue a career in the causes and prevention of cancer from a chemical exposures standpoint?
I think it’s super important to have a strong knowledge and background in the fundamentals like organic chemistry or biochemistry, molecular and cell biology. Understanding the basics like how a cell works and basic chemical principles is crucial to my research. The other thing you need to do is learn how to teach yourself new things, and not be afraid to try new things because science keeps evolving. Many of the techniques my research team does now, did not exist when I was a student. Finally, for someone thinking about getting into science, it’s important to follow your curiosity.
Do you have any last things you want our audience to know?
Studies like the 10KFS cancer study are important because they will help us understand the connection between environmental exposures and human cancer.
Thinking outside the box without constraints: What public health problem would you like to solve first?
Health disparities. It’s tragic that depending on what you look like and where you’re born, you have different access and different health outcomes. I want that to change.
