A precision medicine approach to metabolic therapy for breast cancer in mice

Exploring the anti-cancer potential of SGLT2 inhibitors in breast cancer treatment in pre-clinical and clinical studies

The link between type 2 diabetes mellitus (T2DM) and an increased risk of breast cancer (BC) has prompted the exploration of novel therapeutic strategies targeting shared metabolic pathways. This review focuses on the emerging evidence surrounding the potential anti-cancer effects of sodium-glucose cotransporter-2 (SGLT2) inhibitors in the context of BC. Preclinical studies have demonstrated that various SGLT2 inhibitors, such as canagliflozin, dapagliflozin, ipragliflozin, and empagliflozin, can inhibit the proliferation of BC cells, induce apoptosis, and modulate key cellular signaling pathways. These mechanisms include the activation of AMP-activated protein kinase (AMPK), suppression of mammalian target of rapamycin (mTOR) signaling, and regulation of lipid metabolism and inflammatory mediators. The combination of SGLT2 inhibitors with conventional treatments, including chemotherapy and radiotherapy, as well as targeted therapies like phosphoinositide 3-kinases (PI3K) inhibitors, has shown promising results in enhancing the anti-cancer efficacy and potentially reducing treatment-related toxicities. The identification of specific biomarkers or genetic signatures that predict responsiveness to SGLT2 inhibitor therapy could enable more personalized treatment selection and optimization, particularly for challenging BC subtypes [e, g., triple negative BC (TNBC)]. Ongoing and future clinical trials investigating the use of SGLT2 inhibitors, both as monotherapy and in combination with other agents, will be crucial in elucidating their translational potential and guiding their integration into comprehensive BC care. Overall, SGLT2 inhibitors represent a novel and promising therapeutic approach with the potential to improve clinical outcomes for patients with various subtypes of BC, including the aggressive and chemo-resistant TNBC.

Investigation of co-treatment multi-targeting approaches in breast cancer cell lines

In 2020, breast cancer (BC) has surpassed lung cancer as the most diagnosed cancer in the world. Tumor microenvironment (TME) plays a critical role in resistance to standard therapies and tumor progression. Two key factors within the TME include adenosine, an immunosuppressive molecule, and glucose, which serves as the primary energy source for tumor cells. In this scenario, inhibiting the purinergic pathway and glucose uptake might be a promising strategy. Therefore, we sought to evaluated different treatment approaches in BC cells (Dapagliflozin, a SGLT2 inhibitor; Paclitaxel, the standard chemotherapy for BC; and ARL67156/APCP, inhibitors of CD39 and CD73, respectively). The expression of some membrane markers relevant to resistance was assessed. BC cell-lines (MCF-7 and MDA-MB-231) were co-treated and cell viability, cell cycle, and annexin/PI assays were performed. Our analysis showed promising results, where the combination of these compounds led to cell death by apoptosis/necrosis and cell cycle arrest. Dapagliflozin showed more impact on early apoptosis, whereas Paclitaxel led to late apoptosis/necrosis as the main mechanism of cell death. Inhibiting purinergic signaling also contributed to reducing cell viability together with the other drugs, suggesting it could have an influence on breast cancer survival mechanisms. Indeed, the overexpression of the NT5E gene in patients with ER+ tumors is strongly associated with reduced overall survival and progression-free interval. However, more studies are needed to fully understand the interactions and mechanism underlying these co-treatment multi-targeting approaches.

Thiazolidinedione enhances the efficacy of anti-PD-1 monoclonal antibody in murine melanoma

Several clinical studies observed a surprising beneficial effect of obesity on enhancing immunotherapy responsiveness in patients with melanoma, highlighting an as-yet insufficiently understood relationship between metabolism and immunogenicity. Here, we demonstrate that the thiazolidinedione (TZD) rosiglitazone, a drug commonly used to treat diabetes by sequestering fatty acids in metabolically inert subcutaneous adipose tissue, improved sensitivity to anti-programmed cell death protein 1 (PD-1) treatment in YUMMER1.7 tumor-bearing mice, an initially immunotherapy-sensitive murine melanoma model. We observed a transition from high to intermediate PD-1 expression in tumor-infiltrating CD8+ T cells. Moreover, TZD inhibited PD-1 expression in mouse and human T cells treated in vitro. In addition to its direct impact on immune cells, TZD also decreased circulating insulin concentrations, while insulin induced T cell exhaustion in culture. In TZD-treated mice, we observed higher fatty acid concentrations in the tumor microenvironment, with fatty acids protecting against exhaustion in culture. Together, these data are consistent with an indirect mechanism of TZD inhibiting T cell exhaustion. Finally, we analyzed imaging data from patients with melanoma before and after anti-PD-1 treatment, confirming the beneficial effect of increased subcutaneous fat on anti-PD-1 responsiveness in patients. We also found that the expression of peroxisome proliferator-activated receptor gamma (PPARγ), the canonical activator of lipid uptake and adipogenesis activated by TZD, correlated with overall survival time. Taken together, these data identify a new adjuvant to enhance immunotherapy efficacy in YUMMER1.7 melanoma mice, and discover a new metabolism-based prognostic marker in human melanoma.NEW & NOTEWORTHY Zhang et al. demonstrate that the diabetes drug rosiglitazone improves the efficacy of immunotherapy in mouse melanoma. This effect is both direct and indirect: TZD directly reduces PD-1 expression in CD8+ T cells (i.e., reduces exhaustion), and indirectly reduces exhaustion by lowering insulin levels and increasing local fat. Finally, they demonstrate that hallmarks of TZD action (such as PPARγ expression and subcutaneous fat content) correlate with improved immunotherapy efficacy in humans with melanoma.

Metabolic underpinnings of cancer-related fatigue

Cancer-related fatigue (CRF) is one of the most prevalent and detrimental complications of cancer. Emerging evidence suggests that obesity and insulin resistance are associated with CRF occurrence and severity in cancer patients and survivors. In this narrative review, we analyzed recent studies including both preclinical and clinical research on the relationship between obesity and/or insulin resistance and CRF. We also describe potential mechanisms for these relationships, though with the caveat that because the mechanisms underlying CRF are incompletely understood, the mechanisms mediating the association between obesity/insulin resistance and CRF are similarly incompletely delineated. The data suggest that, in addition to their effects to worsen CRF by directly promoting tumor growth and metastasis, obesity and insulin resistance may also contribute to CRF by inducing chronic inflammation, neuroendocrinological disturbance, and metabolic alterations. Furthermore, studies suggest that patients with obesity and insulin resistance experience more cancer-induced pain and are at more risk of emotional and behavioral disruptions correlated with CRF. However, other studies implied a potentially paradoxical impact of obesity and insulin resistance to reduce CRF symptoms. Despite the need for further investigation utilizing interventions to directly elucidate the mechanisms of cancer-related fatigue, current evidence demonstrates a correlation between obesity and/or insulin resistance and CRF, and suggests potential therapeutics for CRF by targeting obesity and/or obesity-related mediators.

Understanding the Role of Adipocytes and Fibroblasts in Cancer

ABSTRACT

Cancer is currently the second leading cause of death in the United States. There is increasing evidence that the tumor microenvironment (TME) is pivotal for tumorigenesis and metastasis. Recently, adipocytes and cancer-associated fibroblasts (CAFs) in the TME have been shown to play a major role in tumorigenesis of different cancers, specifically melanoma. Animal studies have shown that CAFs and adipocytes within the TME help tumors evade the immune system, for example, by releasing chemokines to blunt the effectiveness of the host defense. Although studies have identified that adipocytes and CAFs play a role in tumorigenesis, adipocyte transition to fibroblast within the TME is fairly unknown. This review intends to elucidate the potential that adipocytes may have to transition to fibroblasts and, as part of the TME, a critical role that CAFs may play in affecting the growth and invasion of tumor cells. Future studies that illuminate the function of adipocytes and CAFs in the TME may pave way for new antitumor therapies.

Optimal control strategies for SGLT2 inhibitors as a novel anti-tumor agent and their effect on human breast cancer cells with the effect of time delay and hyperglycemia

Breast cancer is the most frequent cancer in the world, and it continues to have a significant impact on the total number of cancer deaths. Recently, oncology findings hint at the role of excessive glucose in cancer progression and immune cells' suppression. Sequel to this revelation is ongoing researches on possible inhibition of glucose flow into the tumor micro-environment as therapeutics for malignant treatment. In this study, the effect of glucose blockage therapeutics such as SGLT-2 inhibitors drug on the dynamics of normal, tumors and immune cells interaction is mathematically studied. The asymptomatic nature of the breast cancer is factored into the model using time delay. We first investigate the boundedness and non-negativity of the solution. The condition for existence of critical equilibrium point is determined, and its global stability conditions are derived using Lyapunov function. This revealed that a timely administration of the SGLT-2 inhibitors drug can eliminate tumor cells. Secondly, we determine the sufficient and necessary conditions for optimal control strategy of SGLT-2 inhibitors so as to avert side effects on normal cells using a Pontryagin's Minimum Principle. The results showed that if the ingestion rate of the inhibitor drug is equal to the digestion rate, the tumor cells can be completely eliminated within 9 months without side effects. The analytical results were numerically verified and the qualitative views of interacting cells dynamics is showcased.

Dichloroacetate as a novel pharmaceutical treatment for cancer-related fatigue in melanoma

Cancer-related fatigue (CRF) is one of the most common complications in patients with multiple cancer types and severely affects patients' quality of life. However, there have only been single symptom-relieving adjuvant therapies but no effective pharmaceutical treatment for the CRF syndrome. Dichloroacetate (DCA), a small molecule inhibitor of pyruvate dehydrogenase kinase, has been tested as a potential therapy to slow tumor growth, based largely on its effects in vitro to halt cell division. We found that although DCA did not affect rates of tumor growth or the efficacy of standard cancer treatment (immunotherapy and chemotherapy) in two murine cancer models, DCA preserved physical function in mice with late-stage tumors by reducing circulating lactate concentrations. In vivo liquid chromatography-mass spectrometry/mass spectrometry studies suggest that DCA treatment may preserve membrane potential, postpone proteolysis, and relieve oxidative stress in muscles of tumor-bearing mice. In all, this study provides evidence for DCA as a novel pharmaceutical treatment to maintain physical function and motivation in murine models of CRF.NEW & NOTEWORTHY We identify a new metabolic target for cancer-related fatigue, dichloroacetate (DCA). They demonstrate that in mice, DCA preserves physical function and protects against the detrimental effects of cancer treatment by reducing cancer-induced increases in circulating lactate. As DCA is already FDA approved for another indication, these results could be rapidly translated to clinical trials for this condition for which no pharmaceutical therapies exist beyond symptom management.

A review of the impact of energy balance on triple-negative breast cancer

Cancer cells cannot proliferate without sufficient energy to generate biomass for rapid cell division, as well as to fuel their functions at baseline. For this reason, many recent observational and interventional studies have focused on increasing energy expenditure and/or reducing energy intake during and after cancer treatment. The impact of variance in diet composition and in exercise on cancer outcomes has been detailed extensively elsewhere and is not the primary focus of this review. Instead, in this translational, narrative review we examine studies of how energy balance impacts anticancer immune activation and outcomes in triple-negative breast cancer (TNBC). We discuss preclinical, clinical observational, and the few clinical interventional studies on energy balance in TNBC. We advocate for the implementation of clinical studies to examine how optimizing energy balance-through changes in diet and/or exercise-may optimize the response to immunotherapy in people with TNBC. It is our conviction that by taking a holistic approach that includes energy balance as a key factor to be considered during and after treatment, cancer care may be optimized, and the detrimental effects of cancer treatment and recovery on overall health may be minimized.

Immunometabolism at the crossroads of obesity and cancer-a Keystone Symposia report

Immunometabolism considers the relationship between metabolism and immunity. Typically, researchers focus on either the metabolic pathways within immune cells that affect their function or the impact of immune cells on systemic metabolism. A more holistic approach that considers both these viewpoints is needed. On September 5-8, 2022, experts in the field of immunometabolism met for the Keystone symposium "Immunometabolism at the Crossroads of Obesity and Cancer" to present recent research across the field of immunometabolism, with the setting of obesity and cancer as an ideal example of the complex interplay between metabolism, immunity, and cancer. Speakers highlighted new insights on the metabolic links between tumor cells and immune cells, with a focus on leveraging unique metabolic vulnerabilities of different cell types in the tumor microenvironment as therapeutic targets and demonstrated the effects of diet, the microbiome, and obesity on immune system function and cancer pathogenesis and therapy. Finally, speakers presented new technologies to interrogate the immune system and uncover novel metabolic pathways important for immunity.

Potential Therapies Targeting the Metabolic Reprogramming of Diabetes-Associated Breast Cancer

In recent years, diabetes-associated breast cancer has become a significant clinical challenge. Diabetes is not only a risk factor for breast cancer but also worsens its prognosis. Patients with diabetes usually show hyperglycemia and hyperinsulinemia, which are accompanied by different glucose, protein, and lipid metabolism disorders. Metabolic abnormalities observed in diabetes can induce the occurrence and development of breast cancer. The changes in substrate availability and hormone environment not only create a favorable metabolic environment for tumorigenesis but also induce metabolic reprogramming events required for breast cancer cell transformation. Metabolic reprogramming is the basis for the development, swift proliferation, and survival of cancer cells. Metabolism must also be reprogrammed to support the energy requirements of the biosynthetic processes in cancer cells. In addition, metabolic reprogramming is essential to enable cancer cells to overcome apoptosis signals and promote invasion and metastasis. This review aims to describe the major metabolic changes in diabetes and outline how cancer cells can use cellular metabolic changes to drive abnormal growth and proliferation. We will specifically examine the mechanism of metabolic reprogramming by which diabetes may promote the development of breast cancer, focusing on the role of glucose metabolism, amino acid metabolism, and lipid metabolism in this process and potential therapeutic targets. Although diabetes-associated breast cancer has always been a common health problem, research focused on finding treatments suitable for the specific needs of patients with concurrent conditions is still limited. Most studies are still currently in the pre-clinical stage and mainly focus on reprogramming the glucose metabolism. More research targeting the amino acid and lipid metabolism is needed.