Metformin: The Cellular Gym for Prostate Cancer

Recent research indicates that metformin, a commonly prescribed medication for diabetes, may replicate a key biological impact of exercise in males diagnosed with prostate cancer. This effect involves an elevation in a specific molecule associated with energy regulation and weight management, even in the absence of physical activity. These discoveries suggest that metformin could potentially mitigate the metabolic challenges posed by hormone therapy, a treatment regimen that frequently leads to fatigue and other side effects, thereby limiting patients’ capacity for physical exertion.

This extensive investigation was spearheaded by physician-scientists affiliated with Sylvester Comprehensive Cancer Center, an integral part of the University of Miami Miller School of Medicine, and its findings have been published in the esteemed journal EMBO Molecular Medicine.

Engaging in regular exercise is widely recognized as one of the most effective strategies for maintaining health throughout the course of cancer treatment. It plays a crucial role in moderating body weight, optimizing blood sugar levels, and supporting cardiovascular well-being – all factors that significantly influence how patients experience therapy and their subsequent recovery.

However, for a substantial number of individuals battling cancer, consistent engagement in physical activity is not always a practical possibility. Factors such as profound fatigue, the effects of hormone therapy, persistent pain, or the advanced nature of the disease can restrict physical mobility precisely at a time when maintaining metabolic health is of paramount importance.

This prevailing reality has prompted researchers to pose a pertinent inquiry: if the beneficial effects of exercise are mediated through specific molecular signaling pathways, could these pathways be artificially stimulated through alternative means?

The evidence gathered from this research suggests a potential affirmative answer. Investigators at Sylvester report that metformin administration leads to increased levels of an endogenous molecule that plays a role in the body’s intricate mechanisms for managing energy expenditure and body weight in patients with prostate cancer.

It is crucial to clarify that these findings do not imply that pharmacological intervention can substitute for physical activity. Rather, they provide valuable insights into the internal physiological pathways responsible for the metabolic advantages derived from exercise, and how these pathways might still be activated even when physical movement is considerably curtailed.

This research exemplifies the potential unlocked when laboratory investigations, the study of metabolic biology, and clinical exploration are deliberately converged for interdisciplinary endeavors. Through collaborative efforts spanning Sylvester’s Tumor Biology, Cancer Epigenetics, and Translational & Clinical Oncology programs, we successfully established a correlation between a well-characterized molecular signal and tangible patient data. The outcome is not the identification of a novel cancer biomarker, but rather an enhanced comprehension of how a widely utilized medication might contribute to metabolic well-being during prostate cancer treatment – an outcome of considerable significance to both patients and medical practitioners.

Marijo Bilusic, M.D., Ph.D., a researcher at Sylvester, lead author, genitourinary medical oncologist, and professor of medicine and medical oncology at the Miller School

Central to this collaborative, team-based scientific study is a molecule designated as N-lactoyl-phenylalanine, or Lac-Phe. Although its nomenclature is technical, its biological function is relatively straightforward.

Lac-Phe is synthesized when the body experiences metabolic stress. It is formed through the combination of lactate – a substance that accumulates during strenuous physical activity – and phenylalanine, a fundamental component of protein structure. Researchers initially drew attention to Lac-Phe due to observed spikes in its concentration following intense exercise, coinciding with notable alterations in energy utilization patterns and appetite regulation.

Preclinical investigations and initial human studies have indicated a correlation between elevated Lac-Phe levels and a reduction in appetite, coupled with improved weight management – two physiological responses commonly associated with consistent physical engagement.

The increase in Lac-Phe is not exclusively triggered by exercise. Scientists have documented heightened concentrations of Lac-Phe in individuals undergoing treatment with metformin, even in the absence of any discernible physical exertion. This critical observation prompted a vital question within the realm of cancer care: could a biological pathway typically linked to exercise be pharmacologically engaged in patients whose therapeutic regimens impose limitations on their physical activity?

In an effort to investigate this hypothesis, the Sylvester research team directed their focus towards prostate cancer, a condition where hormone-based therapies are known to adversely affect metabolic processes, thereby contributing to undesirable weight gain, insulin resistance, and increased cardiovascular risk.

Significantly, the levels of Lac-Phe observed in patients receiving metformin treatment closely approximated those previously documented following bouts of rigorous exercise. This phenomenon occurred despite the fact that the patients were not actively exercising at the moment blood samples were collected, and the effect persisted even after the initiation of hormone therapy.

“From a clinical perspective, observing a metabolic signal that mirrored what we typically associate with intense physical exertion was particularly noteworthy,” stated Dr. Bilusic. “For individuals whose treatments or attendant symptoms restrict their ability to engage in physical activity, such an effect could hold significant implications.”

Elevated Lac-Phe concentrations were not found to be associated with an anti-tumor response to metformin. This specific metabolite did not demonstrate any correlation with alterations in prostate-specific antigen (PSA) levels, a widely recognized marker utilized for monitoring prostate cancer progression.

This particular finding is central to the interpretation of the study’s results. While further extensive research is warranted to ascertain the clinical utility of Lac-Phe as a definitive marker of anticancer efficacy, it appears to provide a valuable indication of how the body manages energy balance, weight, and metabolic strain during the course of treatment. To ensure the robustness of these findings and confirm they were not confined to a singular clinical context, these results underwent verification. Indeed, increases in Lac-Phe were also observed in patients undergoing other metabolic therapies, suggesting that Lac-Phe may reflect a more generalized metabolic response rather than a specific drug-induced effect.

“Cancer therapy frequently impacts the body in ways that extend beyond the tumor itself,” commented Dr. Priyamvada Rai, a Sylvester researcher, co-leader of the Tumor Biology Program, and professor of radiation oncology at the Miller School. “Supporting metabolic health can profoundly influence a patient’s tolerance to treatment and their overall sense of well-being over time, even if it doesn’t directly alter tumor proliferation. This study presented an invaluable opportunity to investigate molecular pathways that possess the potential for therapeutic activation to yield improved outcomes for treatments that induce significant metabolic stress.”

Metformin is known to increase the levels of a stress hormone called GDF-15; however, this particular study found that Lac-Phe exhibited a stronger association with changes in body weight. Given that these two markers did not increase concurrently, it suggests that metformin likely influences weight through multiple distinct pathways, with Lac-Phe playing a more prominent role.

“Metabolism is intricately involved in virtually every cellular process,” explained Dr. David B. Lombard, a Sylvester researcher, co-leader of the Cancer Epigenetics Program, and professor of pathology and laboratory medicine at the Miller School. “These findings propose that Lac-Phe could serve as a highly informative signal for deciphering the impact of metformin on metabolic processes in individuals diagnosed with prostate cancer.”

Collectively, these research findings contribute to a more comprehensive understanding of how a commonly prescribed diabetes medication may positively influence metabolic health for patients undergoing treatment for prostate cancer.

“What offers encouragement regarding this research is its salient reminder that the scope of cancer care extends beyond solely targeting tumors – it also encompasses the holistic support of the entire patient,” stated Dr. Rai. “By achieving a deeper understanding of how therapeutic interventions affect metabolism, we can commence the process of identifying innovative strategies to assist patients in preserving their strength, fostering resilience, and maintaining a high quality of life throughout their entire treatment journey.”