Coming. All right. Can you see my slides? And it's just the slides, right? Not my notes. Okay. So thanks so much for inviting me to talk about dietary interventions in endometrial cancer. There we go. I don't have any disclosures. So we know that in addition to cardiovascular disease and diabetes, epidemiological data demonstrates a link between obesity and multiple types of cancer. One of those cancers, obviously, is endometrial cancer, which is the fourth most common cancer in US women. The incidence of mortality are increasing with increasing prevalence of obesity. And obese women with endometrial cancer are also more likely to suffer from other obesity-related comorbidities like type 2 diabetes, hypertension, and heart disease. Women with an elevated BMI who are diagnosed with endometrial cancer are at a greater risk of mortality. So in one study, endometrial cancer patients with a BMI over 40 had a relative risk of death that was six times greater than those of a healthy weight. And this is even in women who have low-risk pathology. So even though their cancer prognosis is good, they die of comorbid conditions. So interventions to combat obesity and its associated metabolic perturbations are desperately needed in women with endometrial cancer. The molecular mechanisms underlying high obesity causes an increased risk of cancer are not totally understood, but there's some key metabolic, inflammatory, and immune-mediated mechanisms that are likely responsible. So first, inflammatory cytokines are secreted from adipose tissue that contributes to the inflammatory milieu of the obese state. This chronic inflammation in and of itself is linked to the development of cancer, but the inflammatory cytokines also increase activation and infiltration of macrophages and other immune cells that can promote cancer. And secretion of these cytokines contributes to insulin resistance, which is also associated with obesity. In addition to storing excess calories as lipids, adipose tissue also has a role in endocrine signaling to the rest of the body in response to metabolic demands. This happens through molecules called adipokines. Leptin and adiponectin are the two most likely contributors. Leptin regulates appetite, and levels are closely correlated with adiposity, and many studies suggest that leptin is linked to the increased prevalence of cancer in obese individuals. It functions as a growth factor and also stimulates expression and activity of aromatase, which we know converts androgens to estrogen, so further increasing the risk of those hormone-proven malignancies. And on the other hand, adiponectin regulates glucose and lipid metabolism, and levels are reduced in obesity, and studies have suggested that adiponectin has anti-tumor effects. Additionally, the secondary consequences of obesity likely have a role in the development of cancer. For example, most individuals develop insulin resistance, which leads to increased levels of insulin, and insulin-like growth factors that stimulates cellular growth and proliferation through activation of the AKT mTOR pathway, and these components of this pathway are often mutated, amplified, or aberrantly expressed in endometrial cancer. And then finally, obesity creates circulating lipid and pre-fatty acid levels, and upregulates lipid synthesis pathways, and this leads to an amplified reservoir of fatty acids that are used to build lipid membranes in rapidly proliferating cells, like cancer cells, and so that's another way that obesity fuels tumor growth. So obesity is associated with excess estrogen, hyperinsulinemia, activation of the AKT mTOR pathway, chronic inflammation, and heightened capacity to harvest dietary energy, which all contribute to the development and progression of endometrial cancer. So in addition to kind of the cancer-directed treatment of endometrial cancer, there are several options for weight loss interventions, and they all have kind of varying amounts of data to support them, but we'll focus today a little bit on our work in dietary interventions, which includes chronic energy restriction and intermittent energy restriction. So caloric restriction has been shown to reduce the risk of cancer and display anti-tumorgenic properties. This study by Barr and colleagues was 71 patients who had low-risk endometrial cancer, or EIN. They had an IUD placed for treatment and were offered bariatric surgery if their BMI was over 35, but if they declined or if their BMI was under 35, they were encouraged to lose weight by diet. The bariatric surgery group lost an average of 33 kilograms, and 86% of patients in that group lost more than 10% of their body weight, but the diet group lost only an average of four kilograms, and only 23% of these women lost more than 10% of their body weight, and they did find that women who lost more than 10% of their body weight were more likely to respond to the progestin. So possibly some kind of promising data, but broad implementation of restricted diets is definitely limited by adherence challenges. So intermittent energy restriction, or IER, is an alternative that's achieved through recurrent alternating periods of normal energy intake interrupted by extended periods of minimal to no energy intake, and it's been shown to cause similar metabolic and anti-inflammatory changes to that of chronic caloric restriction with better compliance. There's a lot of different methods, kind of both in medical and in pop culture. Some of them include the 16-8 diet, which is eating for like a six to eight hour period during the day and fasting for the remainder of the day, the 5-2 approach in one week where you eat one five to 600 calorie meal twice a week, and then regularly on the remaining days, alternate day fasting, and then the eat, stop, eat, which is similar to the 5-2 approach, except you're fasting for the full 24 hours. So how does intermittent energy restriction work? Tumor cells and normal cells respond to nutrient deprivation differently. So normal cells are able to reallocate energy towards maintenance instead of growth pathways when nutrients are scarce, but tumor cells, on the other hand, depend on continuous energy because of their high proliferation rates. So they're not able to make this adaptive switch from growth pathways, and as a result, are rendered more sensitive to additional therapies. In addition, IER also has been known to down-regulate the AKTN-poor pathway, which we saw previously is up-regulated by insulin signaling. It reduces, oops, sorry, reduces inflammation and oxidative stress, and stimulates proliferation of T cells. And interestingly, some recent phase two trials have suggested the benefit of IER to improve efficacy of chemotherapy and hormone therapy in breast cancer. So switching gears, just for a minute, we know that immune checkpoint inhibitors like PD-1 inhibitors are commonly used for endometrial cancer treatment, as PD-1 expression is found in 78% of endometrioid and 68% of serious tumors. In the absence of immunotherapy agents, the interaction of PD-L1 expressed in endometrial cancer cells with the T cell PD-1 receptor results in diminished T cell function and eliminates the immune system's ability to attack the tumor cells. But use of a PD-1 inhibitor prevents this ligand receptor interaction and restores cancer-fighting function to the T cells. So kind of putting these two things together, our hypothesis was that IER would promote anti-tumor immune responses by stimulating T cells, and thus might be a logical and innovative therapeutic partner with PD-1 inhibitors. So we evaluated the anti-tumorigenic effects of switching from a high-fat diet to either IER or a low-fat diet, and adding a PD-1 inhibitor in a mouse model of endometrial cancer. So first we evaluated the efficacy of the PD-1 inhibitor under obese and lean conditions. So mice were fed either a high-fat diet or a low-fat diet to induce an obese or lean phenotype. And then they were injected with adenofree to induce endometrial cancer, and then randomized to PD-1 inhibitor or placebo treatment once they had a palpable tumor. And looking at the tumor weights among the four arms, in the control groups, obesity significantly increased tumor weight by about 2.4 fold, as you can see in this bar on the left here. And then with the addition of PD-1 inhibitors, tumor weight decreased by 68% in the obese mice and by 42% in the lean mice. We also used some RNA sequencing to assess gene expression that's related to immune signaling pathways and inflammatory markers. So in the seat map, you can see red indicates an increase in the tumors of obese compared to lean mice, and green indicates a decrease in this ratio. So multiple genes related to immune pathways are increased in obesity, including those implicated in T-cell and B-cell receptor signaling pathways. And then we looked with flow cytometry, evaluated the effect of PD-1 inhibitor treatment on the tumor T-cell population, and found that the PD-1 inhibitor increases the percentage of CB4 and CD8 T-cells in all of the mice, except for obese mice that were treated with the PD-1 inhibitor. So then we wanted to investigate the effect of adding IER. So to do this after the initial randomization, the high-fat diet that are the obese mice were randomized to either continue the high-fat diet, switch to a low-fat diet, or switch to an IER diet. Again, they were injected with adenocrete to induce endometrial cancer and then treated with either placebo or PD-1 inhibitor for four weeks. So really interestingly, in our mouse model with the adenocrete injection, it induces endometrial cancer about 80 to 85% of the time. And in the mice that were fed, switched to the IER diet, they only developed endometrial cancer about 60% of the time. Not surprisingly, at sacrifice, mean body weight was significantly higher in the high-fat diet group. And then when mice with endometrial cancer were treated with the PD-1 inhibitor, tumor size shrank by about 34 to 68%, depending on the group. And the smallest tumors were in the group that had the IER diet with the PD-1 inhibitor. And then we just have a little bit of metabolomic data from after sacrifice. So on the left, these are amino acids and nucleotide metabolites. And on the right, these are ceramide and cholesterol esters. And all of them are increased with the high-fat diet. And when you switch from a high-fat diet to IER, which is this column on the far right, those profiles actually look most like the low-fat diet fed mice, as opposed to if you switch mice from a high-fat diet to a low-fat diet, those mice, those profiles actually look more like the high-fat diet fed mice. So low-fat diet, switching to a low-fat diet doesn't do as much to modify the cholesterol and amino acid pathways as switching to an IER diet does. And then we just did a little bit of RNA sequencing. This kind of corroborated those findings, but switching to an IER diet preferentially up-regulates genes related to cholesterol metabolism. So kind of overall, what we found from this experiment was that obesity increases inflammatory markers, alters immune signaling and metabolic pathways. Switching from a high-fat diet to an IER diet results in dramatic weight loss, a greater reduction in tumor size and incidence, and reverses the detrimental metabolic effects of obesity in the tumor as compared to mice switched from a high-fat diet to a low-fat diet. So it may be an innovative strategy in the management of obesity-driven endometrial cancer. All right, thank you, Jenny. An innovative way to treat endometrial cancer probably would be to have a high-fat diet.

obesity

endometrial cancer

molecular mechanisms

dietary interventions

intermittent energy restriction