When Erin Giles, PhD, was an undergraduate student in Canada, she never expected she would eventually lead influential research in the United States on the interplay between obesity, menopause, and breast cancer. It may have never happened if she hadn’t joined the University of Colorado Department of Medicine in 2008 as a postdoctoral fellow and became a mentee to Paul MacLean, PhD, director of the Colorado Nutrition Obesity Research Center (NORC) and a professor in the CU Division of Endocrinology, Metabolism, and Diabetes.
The mentor-mentee connection began with a cold email that Giles sent to MacLean around 2007. She had completed her PhD, where she primarily researched why breast cancer may spread to the bone, and was looking for opportunities to learn more about obesity and metabolism — another topic that had sparked her interest during her studies. When she came across the work being done at CU, she was impressed and expressed her interest in MacLean’s extensive research on obesity-related issues.
What Giles didn’t know was that MacLean, who was an associate director of the NORC’s Energy Balance Assessment Core at the time, was working on a collaborative research project with the CU Cancer Center. It was the first time he had collaborated with the cancer center, and he knew it could open the door to a long-lasting partnership and future research opportunities — but there were some collaborative challenges. When MacLean heard from Giles and saw her cancer research experience, a lightbulb went off.
“We were looking for help to build the bridge between cancer and obesity researchers, because we spoke different languages and weren’t on the same page,” MacLean says. “Erin was central to building that bridge. She helped me achieve that vision I had, create a common language between the two centers, and overcome the barriers we faced.”
Today, Giles is an associate professor of movement science and molecular and integrative physiology, as well as director of the Exercise Oncology Lab at the University of Michigan. She continues to foster unique, collaborative research opportunities to advance knowledge about how obesity, cancer, and menopause interact and ways to improve health outcomes.
“I don’t know if I would have ended up here without Paul,” Giles says. “I was his first postdoctoral fellow, and we were both learning along the way. Success requires both people to be committed to the relationship.”
After witnessing the struggles his family members had faced with weight throughout his childhood, MacLean became interested in studying how bodies regulate weight and the metabolic complications that come with obesity. When he was recruited to join the Colorado NORC — one of 11 Nutrition Obesity Research Centers across the country — he soon became a pivotal part of building the center’s reputation and advancing research on obesity and its different facets, including how obesity affects women’s health.
Given that obesity interacts with and can exacerbate different health conditions, MacLean was eager to build research partnerships with other centers on campus to further advance understanding and potential interventions to help patients. So when a CU Cancer Center researcher knocked on MacLean’s office door and asked if he would be interested in partnering on a grant, he jumped at the opportunity.
“There is a strong relationship between obesity promoting a number of different types of cancers,” MacLean says. “It became a priority for me to build a bridge between the NORC and the cancer center so we could combine our efforts to study this relationship. We knew we were much stronger together than alone.”
One of their first projects was investigating the relationship between obesity and breast cancer. However, given the researchers had expertise in different areas, they faced some challenges in communicating their ideas, he explains, saying: “I didn’t speak their language, so I used terms that they didn’t know and asked questions that didn’t always make sense, and vice versa.”
Once Giles became a postdoctoral fellow in the CU Division of Endocrinology, Metabolism, and Diabetes, she joined the collaborative research effort and became a key reason why the team was able to make progress.
“Because I came in with a cancer research background and was integrated with the NORC, I was able to build that bridge by helping the researchers communicate their ideas,” Giles says.
Giles not only helped the researchers navigate their communication barriers. She also contributed meaningful research that helped lay the foundation for future research and collaborations.
“One of her initial studies was helping publish the very first complete energy balance assessment — that’s food intake, energy expenditure, and physical activity — across the female estrus cycle in an animal model of obesity,” MacLean says.
The researchers found that the obese animal models appeared to experience a “yo-yo diet” in which they would eat more one day and eat less another day, whereas the lean animals had a more consistent diet, Giles explains.
“We think this yo-yo diet pattern may set these individuals up for metabolic complications later on,” she says.
MacLean says the research “laid the foundation for us to study what happens with the loss of ovarian function and the relationship between postmenopausal breast cancer and obesity.”
A subsequent study investigated how the loss of ovarian function affects mammary tumors in obese animal models, given that obesity is a risk factor for estrogen receptor-positive breast cancer.
“In this particular model, we were the first to show that after the loss of ovarian function, the obesity-related tumor promotion went way up,” MacLean says. “Essentially, obesity was promoting estrogen receptor-positive tumors without there being estrogen, and that’s what piqued everyone’s interest, because that’s what happens with postmenopausal women, and we wanted to know why this is happening.”
Giles’ research found that the tumors that developed in the obese animals had different gene expression profiles than the tumors in the lean animals. The loss of ovarian function (modeling menopause) leads to an energy imbalance and weight gain — similar to menopausal weight gain in women. It appears that when the obese animals were in this state of energy excess (their food intake was greater than their energy expenditure), the extra nutrients went directly to the tumors — effectively fueling the tumor to grow faster. She hypothesizes that the “yo-yo dieting” across the estrus cycle earlier in life may be a factor in why this happens, but she continues to conduct research on the issue.
“From the research Erin helped with, we were able to secure additional grants and the research questions kept sparking. Other investigators began jumping on board and conducting their own research,” MacLean says. “We’re still mining the data from those early studies and writing papers together based upon that research.”
Although Giles left CU in 2016 and is currently a faculty member at the University of Michigan, the partnership she helped foster between the CU Cancer Center and the NORC continues to strengthen.
“We’ve gotten several team science grants between the centers. We’re looking at the molecular mechanisms of obesity-associated breast cancer risk promotion. We also have clinical studies where cancer survivors are recruited to the CU Anschutz Health and Wellness Center to join a program to help improve their nutrition and physical activity, with the hope that this will help prevent recurrence of their cancers,” MacLean says. “This collaboration has benefited both centers. It took persistence, resilience, and humility on both sides.”
One of the greatest lessons Giles learned from MacLean was how to dream big and get others on board.
“He taught me how to persevere. It wasn’t until my seventh grant application attempt that I got funded — I had to fail six times. He showed me how to take feedback, learn from it, apply it, and move on to be successful,” she says. “My success was his success, and vice versa.”
Giles, who is now leading her own large research grants at her institution, also learned from MacLean how to manage teams, describing MacLean as a strong leader who is down to earth and talented at bringing people together. He not only mentored Giles, but he was also an advocate for her.
“He was great at building a strong team that supports one another and helping me create connections in the science world,” she says. “Now in my current role, I’m doing the same thing and constantly asking: How do I bring these teams together to build my own version of what he built in his lab?”
MacLean describes Giles as a driven and motivated individual who demonstrated great resilience in her research.
“She worked exceptionally hard to create her own path of success,” he says. “For a mentor-mentee relationship to be successful, you have to make sure that the relationship is beneficial for both parties. My mentees bring expertise and knowledge that I don’t have. They can challenge me to be better, just as I can challenge and help them grow.
“For me, building a research enterprise that can be impactful not only here on campus but with the scientific community requires it to be a win-win relationship,” he adds. “With Erin, we both won.”