Adipocyte lipolysis links obesity to breast cancer growth: adipocyte-derived fatty acids drive breast cancer cell proliferation and migration

Stromal lipid species dictate melanoma metastasis and tropism

Cancer cells adapt to signals in the tumor microenvironment (TME), but the TME cues that impact metastasis and tropism are still incompletely understood. We show that abundant stromal lipids from young subcutaneous adipocytes, including phosphatidylcholines, are taken up by melanoma cells, where they upregulate melanoma PI3K-AKT signaling, fatty acid oxidation, oxidative phosphorylation (OXPHOS) leading to oxidative stress, resulting in decreased metastatic burden. High OXPHOS melanoma cells predominantly seed the lung and brain; decreasing oxidative stress with antioxidants shifts tropism from the lung to the liver. By contrast, the aged TME provides fewer total lipids but is rich in ceramides, leading to lower OXPHOS and high metastatic burden. Aged TME ceramides taken up by melanoma cells activate the S1P-STAT3-IL-6 signaling axis and promote liver tropism. Inhibiting OXPHOS in the young TME or blocking the IL-6 receptor in the aged TME reduces the age-specific patterns of metastasis imposed by lipid availability.

Hypertrophic adipocytes increase extracellular vesicle-mediated lipid release and reprogram breast cancer cell metabolism

Obesity worsens cancer-specific survival and all-cause mortality for women diagnosed with breast cancer. Rich in adipose tissue, the breast exhibits increased adipocyte size in obesity, which correlates with poor prognosis. However, adipocyte size is highly heterogeneous as adipose tissue expands through both hyperplasia and hypertrophy; and adipocyte size can increase independently of weight gain. Despite these observations, the impact of adipocyte size on breast cancer cell behavior remains unclear due to insufficient approaches to isolate adipocytes based on size and maintain them in culture for mechanistic studies. Here, we develop strategies to culture size-sorted adipocytes from two mouse models of obesity and test their functional impact on tumor cell malignancy. We find that large adipocytes are transcriptionally distinct from small adipocytes and are enriched for gene sets related to adipose tissue dysfunction, including altered lipid processing. In coculture studies, large adipocytes promote lipid accumulation in breast cancer cells, and enhance their migration, proliferation, and aerobic metabolism in a manner dependent on fatty acid oxidation. These changes coincide with increased release of extracellular vesicles by large versus small adipocytes, which transfer lipid to recipient tumor cells. Moving forward, our findings suggest that adipocyte size could serve as a prognostic biomarker for women with breast cancer and help identify new therapeutic targets to advance clinical outcomes for these patients.

A metabolic shift to the serine pathway induced by lipids fosters epigenetic reprogramming in nontransformed breast cells

Lipid metabolism and the serine, one-carbon, glycine (SOG) and methionine pathways are independently and significantly correlated with estrogen receptor-negative breast cancer (ERneg BC). Here, we propose a link between lipid metabolism and ERneg BC through phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in the de novo serine pathway. We demonstrate that the metabolism of the paradigmatic medium-chain fatty acid octanoic acid leads to a metabolic shift toward the SOG and methionine pathways. PHGDH plays a role in both the forward direction, contributing to the production of S-adenosylmethionine, and the reverse direction, generating the oncometabolite 2-hydroxyglutarate, leading to epigenomic reprogramming and phenotypic plasticity. The methionine cycle is closely linked to the transsulfuration pathway. Consequently, we observe that the shift increases the antioxidant glutathione, which mitigates reactive oxygen species (ROS), enabling survival of a subset of cells that have undergone DNA damage. These metabolic changes contribute to several hallmarks of cancer.

Exploring the potential causal relationship between fatty acid metabolism ratios and major salivary gland carcinomas: A two-sample Mendelian randomization study

Major salivary gland carcinomas (MSGCs) is a rare but aggressive cancer, with limited understanding of its metabolic underpinnings. Lipid metabolism, particularly fatty acid metabolism ratios (FAMRs), has been implicated in various cancers, but its role in MSGCs remains unclear. This study aims to explore the potential causal relationships between specific FAMRs and MSGCs using Mendelian randomization (MR) analysis. A 2-sample MR analysis was conducted using summary data from genome-wide association studies. Three FAMRs, including the ratio of diacylglycerol to triglycerides (DAG/TG), total cholesterol (TC) to total lipids (TL) ratio in large very low-density lipoprotein (VLDL; TC/TL in large VLDL), and triglycerides to total lipids ratio in medium VLDL (TG/TL in medium VLDL), were investigated for their potential causal relationships with MSGCs. Sensitivity analyses, including MR-Egger and leave-one-out tests, were performed to assess pleiotropy and the robustness of the results. The DAG/TG and TC/TL ratios in large VLDL were significantly positively associated with an increased risk of MSGCs (OR = 10.921, P = .004 and OR = 2.651, P = .047, respectively). In contrast, the TG/TL ratio in medium VLDL showed a significant negative association with MSGCs risk (OR = 0.460, P = .041). Sensitivity analyses confirmed the robustness of these associations, with no evidence of significant pleiotropy in 2 of the ratios. This study reveals novel insights into the metabolic basis of MSGCs, demonstrating significant associations between specific FAMRs and MSGCs risk. These findings highlight the potential clinical relevance of FAMRs as biomarkers or therapeutic targets in MSGCs. Future studies should focus on diverse populations and mechanistic research to validate these associations and explore their clinical implications.

Lipid metabolic reprograming: the unsung hero in breast cancer progression and tumor microenvironment

Aberrant lipid metabolism is a well-recognized hallmark of cancer. Notably, breast cancer (BC) arises from a lipid-rich microenvironment and depends significantly on lipid metabolic reprogramming to fulfill its developmental requirements. In this review, we revisit the pivotal role of lipid metabolism in BC, underscoring its impact on the progression and tumor microenvironment. Firstly, we delineate the overall landscape of lipid metabolism in BC, highlighting its roles in tumor progression and patient prognosis. Given that lipids can also act as signaling molecules, we next describe the lipid signaling exchanges between BC cells and other cellular components in the tumor microenvironment. Additionally, we summarize the therapeutic potential of targeting lipid metabolism from the aspects of lipid metabolism processes, lipid-related transcription factors and immunotherapy in BC. Finally, we discuss the possibilities and problems associated with clinical applications of lipid‑targeted therapy in BC, and propose new research directions with advances in spatiotemporal multi-omics.

Body composition alterations in patients with lung cancer

Most patients with lung cancer experience cancer cachexia (CC), a syndrome of skeletal muscle and adipose tissue wasting. Knowledge of body composition changes in patients is limited, however, because most studies have been cross-sectional, comparing patients with noncancer controls or patients with and without CC. Few studies, in contrast, have evaluated body composition in patients with lung cancer over time. This review examines our current understanding of longitudinal body composition changes in patients with lung cancer and identifies modifying factors contributing to variation in muscle and adipose tissue wasting, focusing on biological sex. We identified 32 studies conducting longitudinal measurements of body composition by computed tomography, bioelectrical impedance, dual X-ray absorptiometry, or total body nitrogen, with a total of n = 3,951 patients (35% female). All studies evaluated changes following diagnosis while patients were receiving treatment. Most studies reporting muscle-specific outcomes show decreased skeletal muscle mass, with more pronounced muscle wasting in males and male-enriched populations. In a small number of studies reporting muscle density, the majority show increased myosteatosis. Adiposity changes are less frequently reported, although wasting appears more prevalent in late-stage disease. Further studies are needed to define adipose changes along the lung cancer continuum. Our review emphasizes the need for balanced recruitment based on biological sex and sex-based analyses. In addition, consensus reporting of relevant patient data and outcomes in future studies will allow for meta-analysis and assist in the development of effective treatments for lung CC.

Bisphenol A and DDT disrupt adipocyte function in the mammary gland: implications for breast cancer risk and progression

As breast cancer incidence continues to rise worldwide, there is a pressing need to understand the environmental factors that contribute to its development. Obesogens, including Bisphenol A (BPA) and Dichlorodiphenyltrichloroethane (DDT), are highly prevalent in the environment, and have been associated with obesity and metabolic dysregulation. BPA and DDT, known to disrupt hormone signaling in breast epithelial cells, also promote adipogenesis, lipogenesis, and adipokine secretion in adipose tissue, directly contributing to the pathogenesis of obesity. While the adipose-rich mammary gland may be particularly vulnerable to environmental obesogens, there is a scarcity of research investigating obesogen-mediated changes in adipocytes that drive oncogenic transformation of breast epithelial cells. Here, we review the preclinical and clinical evidence linking BPA and DDT to impaired mammary gland development and breast cancer risk. We discuss how the obesogen-driven mechanisms that contribute to obesity, including changes in adipogenesis, lipogenesis, and adipokine secretion, could provide a pro-inflammatory, nutrient-rich environment that promotes activation of oncogenic pathways in breast epithelial cells. Understanding the role of obesogens in breast cancer risk and progression is essential for informing public health guidelines aimed at minimizing obesogen exposure, to ultimately reduce breast cancer incidence and improve outcomes for women.

Clinical significance of the tumor microenvironment on immune tolerance in gastric cancer

In the realm of oncology, the tumor microenvironment (TME)-comprising extracellular matrix components, immune cells, fibroblasts, and endothelial cells-plays a pivotal role in tumorigenesis, progression, and response to therapeutic interventions. Initially, the TME exhibits tumor-suppressive properties that can inhibit malignant transformation. However, as the tumor progresses, various factors induce immune tolerance, resulting in TME behaving in a state that promotes tumor growth and metastasis in later stages. This state of immunosuppression is crucial as it enables TME to change from a role of killing tumor cells to a role of promoting tumor progression. Gastric cancer is a common malignant tumor of the gastrointestinal tract with an alarmingly high mortality rate. While chemotherapy has historically been the cornerstone of treatment, its efficacy in prolonging survival remains limited. The emergence of immunotherapy has opened new therapeutic pathways, yet the challenge of immune tolerance driven by the gastric cancer microenvironment complicates these efforts. This review aims to elucidate the intricate role of the TME in mediating immune tolerance in gastric cancer and to spotlight innovative strategies and clinical trials designed to enhance the efficacy of immunotherapeutic approaches. By providing a comprehensive theoretical framework, this review seeks to advance the understanding and application of immunotherapy in the treatment of gastric cancer, ultimately contributing to improved patient outcomes.

Interactions between ferroptosis and tumour development mechanisms: Implications for gynaecological cancer therapy (Review)

Ferroptosis is a form of programmed cell death that is distinct from apoptosis. The mechanism involves redox‑active metallic iron and is characterized by an abnormal increase in iron‑dependent lipid reactive oxygen species, which results in high levels of membrane lipid peroxides. The relationship between ferroptosis and gynaecological tumours is complex. Ferroptosis can regulate tumour proliferation, metastasis and chemotherapy resistance, and targeting ferroptosis is a promising antitumour approach. Ferroptosis interacts with mechanisms related to tumorigenesis and development, such as macrophage polarization, the neutrophil trap network, mitochondrial autophagy and cuproptosis. The present review examines recent information on the interaction between the molecular mechanism of ferroptosis and other tumour‑related mechanisms, as well as the involvement of ferroptosis in gynaecological tumours, to identify implications for gynaecological cancer therapy.

Metabolic labeling and targeted modulation of adipocytes

Adipocytes play a critical role in energy storage and endocrine signaling and are associated with various diseases such as cancer and diabetes. Facile strategies to engineer adipocytes have long been pursued for elucidating adipocyte biology and developing adipocyte-based therapies. Herein, we report metabolic glycan labeling of adipocytes and subsequent targeted modulation of adipocytes via click chemistry. We show that azido tags expressed on the surface of adipocytes can persist for over 4 days. By conjugating dibenzocyclooctyne (DBCO)-cargos onto azido-labeled adipocytes via click chemistry, the cargos can be retained on the adipocyte membrane for over 12 hours. We further show that signaling molecules including adiponectin, calreticulin, mannose-binding lectin 2, and milk fat globule-EGF factor 8 protein can be conjugated to adipocytes to orchestrate their phagocytosis by macrophages. The azido-labeled adipocytes grafted into mice can also mediate targeted conjugation of DBCO-cargos in vivo. This adipocyte labeling and targeting technology will facilitate the development of adipocyte-based therapies and provides a new platform for manipulating the interaction between adipocytes and other types of cells.

Obesity alters the fitness of peritumoral adipose tissue, exacerbating tumor invasiveness in renal cancer through the induction of ADAM12 and CYP1B1

Obesity exacerbates the risk and aggressiveness of many types of cancer. Adipose tissue (AT) represents a prevalent component of the tumor microenvironment (TME) and contributes to cancer development and progression. Reciprocal communication between cancer and adipose cells leads to the generation of cancer-associated adipocytes (CAAs), which in turn foster tumor invasiveness by producing paracrine metabolites, adipocytokines, and growth factors. Interfering with the crosstalk between CAAs and cancer cells is of key relevance in the prevention of tumor progression. The present study aimed to analyze the contribution of peritumoral AT in renal cell carcinoma (RCC) progression in lean versus overweight or obese patients. By isolating human adipose-derived stromal/stem cells from the three groups of patients and performing conditioned medium studies with RCC cells along with in vivo xenograft experiments, we found that peritumoral adipocytes from the three groups show a distinct expression profile of genes. In particular, ADAM metallopeptidase domain 12 (ADAM12) and cytochrome P450 family 1 subfamily B member 1 (CYP1B1) were found to be upregulated in obesity and their silencing reduced RCC cell invasiveness. In conclusion, high ADAM12 and CYP1B1 expressions in the peritumoral adipocytes boost tumor invasiveness and may serve as an indicator of poor prognosis in RCC.

TCTN1 Induces Fatty Acid Oxidation to Promote Melanoma Metastasis

Metabolic reprogramming promotes and sustains multiple steps of melanoma metastasis. Identification of key regulators of metabolic reprogramming could lead to the development of treatments for preventing and treating metastatic melanoma. In this study, we identified that tectonic family member 1 (TCTN1) promotes melanoma metastasis by increasing fatty acid oxidation (FAO). In clinical melanoma samples, high expression of TCTN1 correlated with increased metastasis and shorter patient survival. Functionally, TCTN1 promoted melanoma invasion and migration in vitro and distant metastasis in vivo and induced a mesenchymal-like phenotype switch. Mechanistically, TCTN1 acted as a protein scaffold to promote the binding of HADHA and HADHB, subunits of the mitochondrial trifunctional protein complex, thus leading to FAO activation. TCTN1-mediated FAO activated the p38/MAPK signaling pathway in melanoma cells, promoting tumor epithelial-mesenchymal transition and stemness. Molecular docking indicated that the prostaglandin F receptor agonist fluprostenol can block HADHA/HADHB binding, which was confirmed experimentally. Treatment with fluprostenol was able to inhibit TCTN1-induced melanoma invasion and metastasis. Taken together, these findings elucidate the mechanism of TCTN1-mediated promotion of melanoma metastasis and support the potential application of fluprostenol for targeted therapy of metastatic melanoma. Significance: TCTN1 activates fatty acid oxidation to induce melanoma mesenchymal phenotype switching and invasion by promoting the binding of the subunits of MTP, which can be targeted with fluprostenol to inhibit melanoma metastasis.

Immune Dysregulation in Obesity

The immune system plays fundamental roles in maintaining physiological homeostasis. With the increasing prevalence of obesity-a state characterized by chronic inflammation and systemic dyshomeostasis-there is growing scientific and clinical interest in understanding how obesity reshapes immune function. In this review, we propose that obesity is not merely an altered metabolic state but also a fundamentally altered immunological state. We summarize key seminal and recent findings that elucidate how obesity influences immune function, spanning its classical role in microbial defense, its contribution to maladaptive inflammatory diseases such as asthma, and its impact on antitumor immunity. We also explore how obesity modulates immune function within tissue parenchyma, with a particular focus on the role of T cells in adipose tissue. Finally, we consider areas for future research, including investigation of the durable aspects of obesity on immunological function even after weight loss, such as those observed with glucagon-like peptide-1 (GLP-1) receptor agonist treatment. Altogether, this review emphasizes the critical role of systemic metabolism in shaping immune cell functions, with profound implications for tissue homeostasis across various physiological contexts.

Who is Focusing on Women's Health: A Bibliometric Analysis of Global Research Trends on Overweight in Female Patients with Gynecologic or Breast Cancer

Objective

Obesity has become a significant public health concern, strongly linked to various diseases, particularly gynecologic and breast cancers. This bibliometric review aims to analyze global research trends on overweight women, particularly those with gynecologic and breast cancers, to identify research hotspots, key contributors, and emerging areas of study.

Methods

A comprehensive bibliometric analysis was conducted using the Web of Science Core Collection (WoSCC) database, covering the period from January 2013 to September 2024. Articles were screened and analyzed using tools such as VOSviewer and Biblioshiny platform, with metrics including publication volume, citation analysis, and co-authorship networks. Key areas of focus were global research trends, leading countries, institutions, authors, journals, and keyword analysis.

Results

A total of 1452 publications were analyzed. Research activity on the association between obesity and gynecologic/breast cancer has steadily increased, with the United States leading in publications and citations, followed by China and Italy. Core journals included Breast Cancer Research and Treatment and Gynecologic Oncology. Key research areas identified through keyword analysis include the relationship between body mass index (BMI) and cancer risk, survival rates in cancer patients, physical activity, and the role of adipose tissue inflammation in tumor progression. Emerging topics include extracellular vesicles and cancer-associated fibroblasts.

Conclusion

Global research on the relationship between obesity and female-specific cancers has shown significant growth. The findings highlight BMI, survival, and physical activity as central themes. Future research should explore the molecular mechanisms linking obesity to cancer and evaluate weight loss interventions for cancer prevention and treatment.

Role of gut microbial-derived metabolites and other select agents on adipocyte browning

AIMS

Metabolic disease is a multifaceted condition characterized by the disruption of numerous metabolic parameters within the host. Its prevalence has surged significantly in recent years and it has become a prominent non-communicable disease worldwide. The effect of gut microbiota on various beige fat induction is well studied, while the mechanisms behind the link remain unclear. Given that gut microbiota-derived metabolites (meta-metabolites) secreted in the gut serve as a key mode of communication with their host through direct circulation or indirect host physiology modification, understanding the effect of meta-metabolites on adipose tissue is essential.

METHODOLOGY

In our previous in-vivo studies, we observed a correlation between gut microbiota and the formation of beige fat. In this study, we further aimed to validate this correlation by treating the adipocyte cell line (3T3-L1) with meta-metabolites collected from the cecum of mice exhibiting beige adipose tissue formation. Additionally, we treated the adipocyte cell line with known beige fat inducers (L-Rhamnose and Ginsenoside) to assess meta-metabolites' efficacy on beige fat formation.

KEY FINDINGS

Upon treatment with the meta-metabolites from the antibiotic-treated mice, we observed a significant increase in lipid metabolism and beige-specific gene expression. Analyzing the metabolites in these cells revealed that a set of metabolites potentially govern adipocytes, contributing to a metabolically active state. These effects were at par or even better than those of cells treated with L-Rhamnose or Ginsenoside.

SIGNIFICANCE

This research sheds light on the intricate interplay between microbial metabolites and adipose tissue, offering valuable clues for understanding and potentially manipulating these processes for therapeutic purposes.

Adipocyte-derived fatty acid uptake induces obesity-related breast cancer progression: a review

Obesity is a metabolic disorder that occurs when excess energy taken into the body is stored as fat. It is known that this metabolic imbalance affects the development of other diseases such as cancer, cardiovascular diseases, insulin resistance, and diabetes. The main cellular component of adipose tissue is adipocytes, and the environmental interactions of adipocytes are important to study the mechanism of disorder formation. Breast tissue is rich in adipose tissue and obesity is known to be an important risk factor in the development of breast cancer. Altered adipogenesis and lipogenesis processes in adipocytes in breast tissue support tumor development through the transfer of fatty acids released from adipocytes. We believe that blending adipocyte biology with breast cancer development is important for investigating the mechanisms that regulate breast tumor malignant behavior and providing new targets for treatment. Fatty acids, which are an energy source for breast cancer cells, are discussed from molecular perspectives in this review.

Dysregulation of Fatty Acid Metabolism in Breast Cancer and Its Targeted Therapy

Breast cancer has become the number one cancer worldwide, there are challenges in its prevention, diagnosis and treatment, especially the pathogenesis of triple negative breast cancer has not been clear and the treatment dilemma of metastatic breast cancer. Metabolic reprogramming is currently considered to be one of the hallmarks of cancer, and metabolic alterations in breast cancer, including enhanced glycolysis, tricarboxylic acid cycle activity, glutamine catabolism, and fatty acid biosynthesis, are manifested differently in different breast cancer subtypes and have a complex relationship with tumor growth, metastasis, death, and drug resistance. At present, inhibitors of fatty acid synthesis and oxidation related enzymes have a certain effect in the treatment of breast cancer. In this paper, we review the studies on fatty acid metabolism in breast cancer to better understand the mechanism of fatty acid metabolism in breast cancer pathogenesis and hope to provide new ideas for targeting fatty acid metabolism in the treatment of breast cancer.

Mechanisms by which obesity regulates inflammation and anti-tumor immunity in cancer

Obesity is associated with an increased risk for 13 different cancers. The increased risk for cancer in obesity is mediated by obesity-associated changes in the immune system. Obesity has distinct effects on different types of inflammation that are tied to tumorigenesis. For example, obesity promotes chronic inflammation in adipose tissue that is tumor-promoting in peripheral tissues. Conversely, obesity inhibits acute inflammation that rejects tumors. Obesity therefore promotes cancer by differentially regulating chronic versus acute inflammation. Given that obesity is chronic, the initial inflammation in adipose tissue will lead to systemic inflammation that could induce compensatory anti-inflammatory reactions in peripheral tissues to suppress chronic inflammation. The overall effect of obesity in peripheral tissues is therefore dependent on the duration and severity of obesity. Adipose tissue is a complex tissue that is composed of many cell types in addition to adipocytes. Further, adipose tissue cellularity is different at different anatomical sites throughout the body. Consequently, the sensitivity of adipose tissue to obesity is dependent on the anatomical location of the adipose depot. For example, obesity induces more inflammation in visceral than subcutaneous adipose tissue. Based on these studies, the mechanisms by which obesity promotes tumorigenesis are multifactorial and immune cell type-specific. The objective of our paper is to discuss the cellular mechanisms by which obesity promotes tumorigenesis by regulating distinct types of inflammation in adipose tissue and the tumor microenvironment.

Adipocytes reprogram the proteome of breast cancer cells in organotypic three-dimensional cell cultures

While epidemiological evidence has long linked obesity with an increased risk of breast cancer, the intricate interactions between adipocytes and cancer cells within the tumor microenvironment remain largely uncharted territory. The use of organotypic three-dimensional (3D) cell cultures that more accurately mimic the spatial architecture of tumors represents an innovative approach to this complex issue. In the present study, we investigated the effects of adipocytes on the proteome of Hs578t breast cancer cells cultured in a 3D microenvironment. Using different treatments, we rigorously optimized the experimental conditions to induce the optimal differentiation of 3T3-L1 fibroblasts into mature adipocytes. Then, we grow the Hs578t cells in a simulated microenvironment using an on-top model for organotypic 3D cultures. Our data showed that cancer cells formed 3D stellate-like architectures when grown over an extracellular matrix proteins-enriched scaffold for 48 h. Proteomic profiling using LC-MS/MS mass spectrometry of Hs578t cells grown in 3D conditions with or without the adipocyte-enriched culture discovered 916 unique proteins. Of these, 605 showed no significant changes in abundance, whereas 87 proteins were significantly upregulated and 224 downregulated after interaction with fat cells (p < 0.05, FC > 2.0). Bioinformatic analysis of upregulated proteins indicated that the most enriched GO terms and molecular functions were related to lipids transport, cell differentiation, hypoxia response, and cell junctions. In addition, several modulated proteins have been previously associated with breast cancer progression. Interestingly, lipid transport proteins, including PITPNM2, ATP2C1, ABCA12, HDLBP, and APOB, showed perturbations in their expression, which were also associated with low overall survival in breast cancer patients. Functional studies showed that the knockdown of apolipoprotein B (APOB) expression in Hs578t cells reduced the size of 3D cellular structures. Moreover, APOB-knocked cells cocultured with adipocytes for 48 h exhibited a significant decrease of intracellular lipids, whereas an increase in the adipocytes was found. Our results indicate that the 3D microenvironment and the adipocytes crosstalk reprogram the proteome of breast cancer cells. These data help us understand the environmental effects in gene expression and contribute to discovering novel tumor proteins with potential intervention in breast cancer therapy.

Obesity, white adipose tissue and cancer

White adipose tissue (WAT) is crucial for whole-body energy homeostasis and plays an important role in metabolic and hormonal regulation. While healthy WAT undergoes controlled expansion and contraction to meet the body's requirements, dysfunctional WAT in conditions like obesity is characterized by excessive tissue expansion, alterations in lipid homeostasis, inflammation, hypoxia, and fibrosis. Obesity is strongly associated with an increased risk of numerous cancers, with obesity-induced WAT dysfunction influencing cancer development through various mechanisms involving both systemic and local interactions between adipose tissue and tumors. Unhealthy obese WAT affects circulating levels of free fatty acids and factors like leptin, adiponectin, and insulin, altering systemic lipid metabolism and inducing inflammation that supports tumor growth. Similar mechanisms are observed locally in an adipose-rich tumor microenvironment (TME), where WAT cells can also trigger extracellular matrix remodeling, thereby enhancing the TME's ability to promote tumor growth. Moreover, tumors reciprocally interact with WAT, creating a bidirectional communication that further enhances tumorigenesis. This review focuses on the complex interplay between obesity, WAT dysfunction, and primary tumor growth, highlighting potential targets for therapeutic intervention.

Glucose impacts onto the reciprocal reprogramming between mammary adipocytes and cancer cells

An established hallmark of cancer cells is metabolic reprogramming, largely consisting in the exacerbated glucose uptake. Adipocytes in the tumor microenvironment contribute toward breast cancer (BC) progression and are highly responsive to metabolic fluctuations. Metabolic conditions characterizing obesity and/or diabetes associate with increased BC incidence and mortality. To explore BC-adipocytes interaction and define the impact of glucose in such dialogue, Mammary Adipose-derived Mesenchymal Stem Cells (MAd-MSCs) were differentiated into adipocytes and co-cultured with ER+ BC cells while exposed to glucose concentration resembling hyperglycemia or normoglycemia in humans (25mM or 5.5mM). The transcriptome of both cell types in co-culture as in mono-culture was profiled by RNA-Seq to define the impact of adipocytes on BC cells and viceversa (i), the action of glucose on BC cells, adipocytes (ii) and their crosstalk (iii). Noteworthy, we provided evidence that co-culture with adipocytes in a glucose-rich environment determined a re-program of BC cell transcriptome driving lipid accumulation, a hallmark of BC aggressiveness, promoting stem-like properties and reducing Tamoxifen responsiveness. Moreover, our data point out to a transcriptional effect through which BC cells induce adipocytes de-lipidation, paralleled by pluripotency gain, as source of lipids when glucose lowering occurs. Thus, modulating plasticity of peri-tumoral adipocytes may represent a key point for halting BC progression in metabolically unbalanced patients.

Histologic Characterization of Tumor-Adjacent Mammary Adipose Tissue in Normal-Weight and Overweight/Obese Patients with Triple-Negative Breast Cancer

Background: Obesity is a risk factor of several types of cancer, including breast cancer. In this study, we aimed to histologically characterize the adipose tissue of the tumor microenvironment (TME) of triple-negative breast cancer (TNBC) in overweight/obese versus normal-weight patients. Methods: TNBC tissue sections from normal-weight (BMI<25) and overweight/obese patients (BMI≥25) were stained with antibodies against CD68, CD163, CD31, CD34, and vimentin. At the invasive tumor front, positive cells were counted in tumor adjacent adipose tissue (AT) and within cancer tissue (CT). Further, the size of the tumor-adjacent and distant mammary adipocytes was determined in perilipin stained sections. Expression of ANGPTL4, CD36 and FABP4, proteins involved in fatty acid metabolism, was analyzed in marginal tumor cells using an immune reactive score. Results: Overweight/obese TNBC patients had significantly larger adipocytes, higher numbers of CD163+ macrophages (BMI<25: 2.80 vs. BMI≥25: 10.45; p = 0.011) and lower numbers of CD31+ (BMI<25: 4.20 vs. BMI≥25: 2.40; p = 0.018) and CD34+ (BMI<25: 14.60 vs. BMI≥25: 5.20; p = 0.045) cells as markers of angiogenesis in the AT as well as a higher frequency of cancer-associated-fibroblast-like cells in the AT and CT (BMI<25: 7.60 vs. BMI≥25: 25.39 in total; p = 0.001). Moreover, expression of CD36 (BMI<25: 2.15 vs. BMI≥25: 2.60; p = 0.041) and ANGPTL4 (BMI<25: 6.00 vs. BMI≥25: 9.80; p = 0.026) was elevated in the TNBC cells of overweight/obese patients. Conclusions: Our data suggest BMI-related changes in the TME of overweight/obese TNBC patients, including hypertrophied adipocytes, reduced vascularization, more M2-like macrophages and CAF-like cells, and an increase in the expression of fatty acid metabolizing proteins in marginal tumor cells, all contributing to a more tumor-promoting, immunosuppressive environment.

High BMI Is Associated with Changes in Peritumor Breast Adipose Tissue That Increase the Invasive Activity of Triple-Negative Breast Cancer Cells

Breast cancer is the most common cancer in women with multiple risk factors including smoking, genetics, environmental factors, and obesity. Smoking and obesity are the top two risk factors for the development of breast cancer. The effect of obesity on adipose tissue mediates the pathogenesis of breast cancer in the context of obesity. Triple-negative breast cancer (TNBC) is a breast cancer subtype within which the cells lack estrogen, progesterone, and HER2 receptors. TNBC is the deadliest breast cancer subtype. The 5-year survival rates for patients with TNBC are 8-16% lower than the 5-year survival rates for patients with estrogen-receptor-positive breast tumors. In addition, TNBC patients have early relapse rates (3-5 years after diagnosis). Obesity is associated with an increased risk for TNBC, larger TNBC tumors, and increased breast cancer metastasis compared with lean women. Thus, novel therapeutic approaches are warranted to treat TNBC in the context of obesity. In this paper, we show that peritumor breast adipose-derived secretome (ADS) from patients with a high (>30) BMI is a stronger inducer of TNBC cell invasiveness and JAG1 expression than peritumor breast ADS from patients with low (<30) BMI. These findings indicate that patient BMI-associated changes in peritumor AT induce changes in peritumor ADS, which in turn acts on TNBC cells to stimulate JAG1 expression and cancer cell invasiveness.

Adipose Tissue Plasticity: A Comprehensive Definition and Multidimensional Insight

Adipose tissue is composed of adipocytes, stromal vascular fraction, nerves, surrounding immune cells, and the extracellular matrix. Under various physiological or pathological conditions, adipose tissue shifts cellular composition, lipid storage, and organelle dynamics to respond to the stress; this remodeling is called "adipose tissue plasticity". Adipose tissue plasticity includes changes in the size, species, number, lipid storage capacity, and differentiation function of adipocytes, as well as alterations in the distribution and cellular composition of adipose tissue. This plasticity has a major role in growth, obesity, organismal protection, and internal environmental homeostasis. Moreover, certain thresholds exist for this plasticity with significant individualized differences. Here, we comprehensively elaborate on the specific connotation of adipose tissue plasticity and the relationship between this plasticity and the development of many diseases. Meanwhile, we summarize possible strategies for treating obesity in response to adipose tissue plasticity, intending to provide new insights into the dynamic changes in adipose tissue and contribute new ideas to relevant clinical problems.

1α,25-Dihydroxyvitamin D Downregulates Adipocyte Impact on Breast Cancer Cell Migration and Adipokine Release

BACKGROUND/OBJECTIVES

Excess adiposity is associated with a higher risk of breast cancer metastasis and mortality. Evidence suggests that dietary vitamin D inhibits breast cancer metastasis. However, the mechanistic link between vitamin D's regulation of adipocyte metabolism and metastasis has not been previously investigated. Therefore, the purpose of these experiments was to examine the effect of the active form of vitamin D, 1α,25-dihydroxyvitamin D (1,25(OH)2D), on adipocyte release of bioactive compounds and whether the impact on adipocytes leads to inhibition of breast cancer cell migration, an important step of metastasis.

METHODS

Differentiated 3T3-L1 adipocytes were treated with 1,25(OH)2D for two days, followed by either harvesting the adipocytes or collecting adipocyte-conditioned media without 1,25(OH)2D. A transwell migration assay was conducted with vehicle- or 1,25(OH)2D-conditioned media. In order to explore the mechanism underlying effects on breast cancer metastatic capability, the mRNA expression of leptin, adiponectin, insulin-like growth factor (IGF-1), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) was measured in adipocytes following either vehicle or 1,25(OH)2D treatment.

RESULTS

Conditioned media from 1,25(OH)2D-treated adipocytes inhibited the migration of metastatic MDA-MB-231 breast cancer cells compared to conditioned media from vehicle-treated adipocytes. Treatment of adipocytes with 1,25(OH)2D decreased mRNA expression of leptin, adiponectin, IGF-1, IL-6, and MCP-1. Consistent with mRNA expression, concentrations of leptin, adiponectin, IGF-1, and IL-6 in adipocyte-conditioned media were decreased with 1,25(OH)2D treatment, although MCP-1 remained unchanged.

CONCLUSIONS

In summary, these results suggest that 1,25(OH)2D alters adipocyte secretions to prevent breast cancer metastasis.

Association between body mass index and lymph node metastasis among women with cervical cancer: a systematic review and network meta-analysis

PURPOSE

Lymph node status is a determinant of survival in patients with early-stage cervical cancer. However, the relationship between obesity and lymph node status remains unclear. Therefore, this systematic review aims to evaluate the correlation between body mass index (BMI) and lymph node metastasis in cervical cancer.

METHODS

Cohort studies through six databases were reviewed until December 2021. Odds ratios (ORs) for lymphatic metastasis were estimated using random-effects models and network meta-analysis. BMI groups for lymph node metastasis were ranked. Heterogeneities were assessed using I2. Subgroup analyses were performed to determine possible sources of heterogeneity.

RESULTS

No significant difference was found between obese (BMI ≥ 25) and non-obese patients (BMI < 25) (OR = 1.01; 95% CI 0.69-1.47; P = 0.97). In subgroup analyses, obesity was associated with higher risk among the Americans and advanced-stage patients. The grouping analysis based on BMI and the rankogram values revealed that the '35 ≤ BMI' group had the highest risk of lymph node metastasis.

CONCLUSION

Although there were no significant differences in lymph node metastasis between obese and non-obese cervical cancer patients in overall analysis, patients with BMI ≥ 35 were at significantly higher risk of lymph node metastasis.

Redox and metabolic reprogramming in breast cancer and cancer-associated adipose tissue

Redox and metabolic processes are tightly coupled in both physiological and pathological conditions. In cancer, their integration occurs at multiple levels and is characterized by synchronized reprogramming both in the tumor tissue and its specific but heterogeneous microenvironment. In breast cancer, the principal microenvironment is the cancer-associated adipose tissue (CAAT). Understanding how the redox-metabolic reprogramming becomes coordinated in human breast cancer is imperative both for cancer prevention and for the establishment of new therapeutic approaches. This review aims to provide an overview of the current knowledge of the redox profiles and regulation of intermediary metabolism in breast cancer while considering the tumor and CAAT of breast cancer as a unique Warburg's pseudo-organ. As cancer is now recognized as a systemic metabolic disease, we have paid particular attention to the cell-specific redox-metabolic reprogramming and the roles of estrogen receptors and circadian rhythms, as well as their crosstalk in the development, growth, progression, and prognosis of breast cancer.

Lipid metabolism associated crosstalk: the bidirectional interaction between cancer cells and immune/stromal cells within the tumor microenvironment for prognostic insight

Cancer is closely related to lipid metabolism, with the tumor microenvironment (TME) containing numerous lipid metabolic interactions. Cancer cells can bidirectionally interact with immune and stromal cells, the major components of the TME. This interaction is primarily mediated by fatty acids (FAs), cholesterol, and phospholipids. These interactions can lead to various physiological changes, including immune suppression, cancer cell proliferation, dissemination, and anti-apoptotic effects on cancer cells. The physiological modulation resulting from this lipid metabolism-associated crosstalk between cancer cells and immune/stromal cells provides valuable insights into cancer prognosis. A comprehensive literature review was conducted to examine the function of the bidirectional lipid metabolism interactions between cancer cells and immune/stromal cells within the TME, particularly how these interactions influence cancer prognosis. A novel autophagy-extracellular vesicle (EV) pathway has been proposed as a mediator of lipid metabolism interactions between cancer cells and immune cells/stromal cells, impacting cancer prognosis. As a result, different forms of lipid metabolism interactions have been described as being linked to cancer prognosis, including those mediated by the autophagy-EV pathway. In conclusion, understanding the bidirectional lipid metabolism interactions between cancer cells and stromal/immune cells in the TME can help develop more advanced prognostic approaches for cancer patients.

Adipocytes promote metastasis of breast cancer by attenuating the FOXO1 effects and regulating copper homeostasis

BACKGROUND

Obesity and the forkhead box O1(FOXO1) affect the survival of breast cancer patients, but the underlying mechanism remains unclear. We aimed to investigate the role of FOXO1 in obesity-associated-breast cancer.

METHODS

We screened 383 breast disease patients from the first affiliated hospital with Nanjing Medical University in 2020. We performed wound healing, transwell, matrigel assays to assess the metastatic ability of cancer cells. We adopted mRNAs sequencing to select the differentially expressed transcripts in breast cancer. We applied immunohistochemistry, western blot, tissue microarrays to assess the level of FOXO1 and epithelial-mesenchymal transition (EMT) pathways. We conducted bioinformatic analysis to investigate interactions between FOXO1 and miR-135b. We used fluorescence in situ hybridization, RT-qPCR to confirm the characteristics of circCNIH4. We conducted luciferase reporter assay, rescue experiments to investigate interactions between circCNIH4 and miR-135b.

RESULTS

Obesity was positively correlated with the incidence and progression of breast cancer. Adipocytes enhanced the migration of breast cancer and attenuated the effects of FOXO1. MiR-135b was a binding gene of FOXO1 and was regulated by circCNIH4. CircCNIH4 exhibited antitumor activity in vitro and in vivo.

CONCLUSION

Adipocytes might accelerate the progression of breast cancer by modulating FOXO1/miR-135b/ circCNIH4 /EMT axis and regulating copper homeostasis.

Succinylation of 14-3-3 theta by CPT1A promotes survival and paclitaxel resistance in nasal type extranodal natural killer/T-cell lymphoma

BACKGROUND

The aggressive and refractory extranodal natural killer/T-cell lymphoma, nasal type (ENKTL-NT) is a subtype of non-Hodgkin's lymphoma. Succinylation promotes progression in a variety of tumors, but its mechanism in ENKTL-NT is unclear.

METHODS

Bioinformatic analysis was performed to screen differentially expressed genes in the ENKTL dataset. Cell transfection techniques were used for knockdown and overexpression of genes. The mRNA and protein expression were detected using RT-qPCR and western blot, respectively. Immunohistochemical staining was used to assess protein expression in situ. For the detection of cell proliferation activity, CCK-8, clonal formation, and EDU staining assays were used. Flow cytometry was employed to detect apoptosis. Co-immunoprecipitation was utilized for the identification of protein interactions and succinylation modifications.

RESULTS

Succinyltransferase CPT1A was highly elevated in ENKTL-NT and was associated with a dismal prognosis. CPT1A knockdown suppressed SNK-6 cells' proliferation and induced apoptosis, while these effects were reversed by the overexpression of 14-3-3theta. Co-immunoprecipitation results showed that CPT1A caused succinylation of 14-3-3theta at site of K85, thereby enhancing the protein stability. Suppression of CPT1A-induced succinylation of 14-3-3theta by ST1326 resulted in the inhibition of SNK-6 cell proliferation and increased apoptosis. Paclitaxel combined with knockdown of CPT1A significantly inhibited the proliferation of ENKTL-NT compared to paclitaxel alone.

CONCLUSION

CPT1A induces succinylation of 14-3-3theta at the K85 site, promoting ENKTL-NT proliferation. The anti-ENKTL activity of paclitaxel was improved when combined with CPT1A knockdown.

Cancer-associated adipocytes in the ovarian cancer microenvironment

The tumor microenvironment (TME) plays a critical role in high energy metabolism during tumorigenesis, progression and metastasis. Among them, adipocytes, as an important component of the TME, can transform into cancer-associated adipocytes (CAAs) through dedifferentiation via interactions with tumor cells. These CAAs provide nutrients, growth factors, cytokines and metabolites to the tumor and later transdifferentiate into other stromal cells at a later stage to alter tumor growth, metastasis and the drug response and ultimately influence the treatment and prognosis of ovarian cancer. This review outlines the physiological functions of CAAs and discusses the progress in the use of CAAs as therapeutic targets in ovarian cancer.

The obese inflammatory microenvironment may promote breast DCIS progression

Introduction

Ductal carcinoma in situ (DCIS), characterized by a proliferation of neoplastic cells confined within the mammary ducts, is distinctly isolated from the surrounding stroma by an almost uninterrupted layer of myoepithelial cells (MECs) and by the basement membrane. Heightened interactions within the adipose microenvironment, particularly in obese patients, may play a key role in the transition from DCIS to invasive ductal carcinoma (IDC), which is attracting growing interest in scientific research. Adipose tissue undergoes metabolic changes in obesity, impacting adipokine secretion and promoting chronic inflammation. This study aimed to assess the interactions between DCIS, including in situ cancer cells and MECs, and the various components of its inflammatory adipose microenvironment (adipocytes and macrophages).

Methods

To this end, a 3D co-culture model was developed using bicellular bi-fluorescent DCIS-like tumoroids, adipose cells, and macrophages to investigate the influence of the inflammatory adipose microenvironment on DCIS progression.

Results

The 3D co-culture model demonstrated an inhibition of the expression of genes involved in apoptosis (BAX, BAG1, BCL2, CASP3, CASP8, and CASP9), and an increase in genes related to cell survival (TP53, JUN, and TGFB1), inflammation (TNF-α, PTGS2, IL-6R), invasion and metastasis (TIMP1 and MMP-9) in cancer cells of the tumoroids under inflammatory conditions versus a non-inflammatory microenvironment. On the contrary, it confirmed the compromised functionality of MECs, resulting in the loss of their protective effects against cancer cells. Adipocytes from obese women showed a significant increase in the expression of all studied myofibroblast-associated genes (myoCAFs), such as FAP and α-SMA. In contrast, adipocytes from normal-weight women expressed markers of inflammatory fibroblast phenotypes (iCAF) characterized by a significant increase in the expression of LIF and inflammatory cytokines such as TNF-α, IL-1β, IL-8, and CXCL-10. These changes also influenced macrophage polarization, leading to a pro-inflammatory M1 phenotype. In contrast, myoCAF-associated adipocytes, and the cancer-promoting microenvironment polarized macrophages towards an M2 phenotype, characterized by high CD163 receptor expression and IL-10 and TGF-β secretion.

Discussion

Reciprocal interactions between the tumoroid and its microenvironment, particularly in obesity, led to transcriptomic changes in adipocytes and macrophages, may participate in breast cancer progression while disrupting the integrity of the MEC layer. These results underlined the importance of adipose tissue in cancer progression.

Associations between Diabetes Mellitus and Selected Cancers

Cancer is one of the major causes of mortality and is the second leading cause of death. Diabetes mellitus is a serious and growing problem worldwide, and its prevalence continues to grow; it is the 12th leading cause of death. An association between diabetes mellitus and cancer has been suggested for more than 100 years. Diabetes is a common disease diagnosed among patients with cancer, and evidence indicates that approximately 8-18% of patients with cancer have diabetes, with investigations suggesting an association between diabetes and some particular cancers, increasing the risk for developing cancers such as pancreatic, liver, colon, breast, stomach, and a few others. Breast and colorectal cancers have increased from 20% to 30% and there is a 97% increased risk of intrahepatic cholangiocarcinoma or endometrial cancer. On the other hand, a number of cancers and cancer therapies increase the risk of diabetes mellitus. Complications due to diabetes in patients with cancer may influence the choice of cancer therapy. Unfortunately, the mechanisms of the associations between diabetes mellitus and cancer are still unknown. The aim of this review is to summarize the association of diabetes mellitus with selected cancers and update the evidence on the underlying mechanisms of this association.

Epigallocatechin gallate protects against fat and muscle atrophy in B16BL6 melanoma-bearing mice on a high-fat diet

AIMS

Epidemiological evidence indicates that there is a substantial association between body mass index (BMI) and at least ten forms of cancer, including melanoma, and BMI imbalance contributes to the poor survival rate of cancer patients before and after therapy. Nevertheless, few pharmacological studies on models of obesity and cancer have been reported. In this study, we administered epigallocatechin gallate (EGCG) to B16BL6 tumor-bearing mice that received a high-fat diet (HFD) to examine its impact.

METHODS

B16BL6 tumor-bearing mice were fed a HFD. Body weight and food intake were documented every week. We conducted a Western blot analysis to examine the protein levels in the tumor, gastrocnemius (GAS), and tibialis anterior (TA) muscles, as well as the inguinal and epididymal white adipose tissues (iWAT and eWAT).

KEY FINDINGS

EGCG has been shown to have anti-cancer effects equivalent to those of cisplatin, a chemotherapy drug. Furthermore, EGCG protected against the loss of epidydimal white adipose tissue by regulating protein levels of lipolysis factors of adipose triglyceride lipase and hormone-sensitive lipase as well as WAT browning factors of uncoupling protein 1, as opposed to cisplatin. EGCG was shown to reduce the protein levels of muscular atrophy factors of muscle RING-finger protein-1, whereas cisplatin did not contribute to rescuing the atrophy of TA and GAS muscles.

CONCLUSION

Taken together, our findings indicate that EGCG has a preventive effect against cachexia symptoms and has anti-cancer effects similar to those of cisplatin in tumor-bearing mice fed a high-fat diet.

Long-Term High-Fat Diet Limits the Protective Effect of Spontaneous Physical Activity on Mammary Carcinogenesis

Breast cancer is influenced by factors such as diet, a sedentary lifestyle, obesity, and postmenopausal status, which are all linked to prolonged hormonal and inflammatory exposure. Physical activity offers protection against breast cancer by modulating hormones, immune responses, and oxidative defenses. This study aimed to assess how a prolonged high-fat diet (HFD) affects the effectiveness of physical activity in preventing and managing mammary tumorigenesis. Ovariectomised C57BL/6 mice were provided with an enriched environment to induce spontaneous physical activity while being fed HFD. After 44 days (short-term, ST HFD) or 88 days (long-term, LT HFD), syngenic EO771 cells were implanted into mammary glands, and tumour growth was monitored until sacrifice. Despite similar physical activity and food intake, the LT HFD group exhibited higher visceral adipose tissue mass and reduced skeletal muscle mass. In the tumour microenvironment, the LT HFD group showed decreased NK cells and TCD8+ cells, with a trend toward increased T regulatory cells, leading to a collapse of the T8/Treg ratio. Additionally, the LT HFD group displayed decreased tumour triglyceride content and altered enzyme activities indicative of oxidative stress. Prolonged exposure to HFD was associated with tumour growth despite elevated physical activity, promoting a tolerogenic tumour microenvironment. Future studies should explore inter-organ exchanges between tumour and tissues.

Resveratrol, a novel inhibitor of fatty acid binding protein 5, inhibits cervical cancer metastasis by suppressing fatty acid transport into nucleus and downstream pathways

BACKGROUND AND PURPOSE

Because of cervical cancer (CC) metastasis, the prognosis of diagnosed patients is poor. However, the molecular mechanisms and therapeutic approach for metastatic CC remain elusive.

EXPERIMENTAL APPROACH

In this study, we first evaluated the effect of resveratrol (RSV) on CC cell migration and metastasis. Via an activity-based protein profiling (ABPP) approach, a photoaffinity probe of RSV (RSV-P) was synthesized, and the protein targets of RSV in HeLa cells were identified. Based on target information and subsequent in vivo and in vitro validation experiments, we finally elucidated the mechanism of RSV corresponding to its antimetastatic activity.

KEY RESULTS

The results showed that RSV concentration-dependently suppressed CC cell migration and metastasis. A list of proteins was identified as the targets of RSV, through the ABPP approach with RSV-P, among which fatty acid binding protein 5 (FABP5) attracted our attention based on The Cancer Genome Atlas (TCGA) database analysis. Subsequent knockout and overexpression experiments confirmed that RSV directly interacted with FABP5 to inhibit fatty acid transport into the nucleus, thereby suppressing downstream matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) expression, thus inhibiting CC metastasis.

CONCLUSIONS AND IMPLICATIONS

Our study confirmed the key role of FABP5 in CC metastasis and provided important target information for the design of therapeutic lead compounds for metastatic CC.

AMPK as a mediator of tissue preservation: time for a shift in dogma?

Ground-breaking discoveries have established 5'-AMP-activated protein kinase (AMPK) as a central sensor of metabolic stress in cells and tissues. AMPK is activated through cellular starvation, exercise and drugs by either directly or indirectly affecting the intracellular AMP (or ADP) to ATP ratio. In turn, AMPK regulates multiple processes of cell metabolism, such as the maintenance of cellular ATP levels, via the regulation of fatty acid oxidation, glucose uptake, glycolysis, autophagy, mitochondrial biogenesis and degradation, and insulin sensitivity. Moreover, AMPK inhibits anabolic processes, such as lipogenesis and protein synthesis. These findings support the notion that AMPK is a crucial regulator of cell catabolism. However, studies have revealed that AMPK's role in cell homeostasis might not be as unidirectional as originally thought. This Review explores emerging evidence for AMPK as a promoter of cell survival and an enhancer of anabolic capacity in skeletal muscle and adipose tissue during catabolic crises. We discuss AMPK-activating interventions for tissue preservation during tissue wasting in cancer-associated cachexia and explore the clinical potential of AMPK activation in wasting conditions. Overall, we provide arguments that call for a shift in the current dogma of AMPK as a mere regulator of cell catabolism, concluding that AMPK has an unexpected role in tissue preservation.

Dysfunctional adipocytes promote tumor progression through YAP/TAZ-dependent cancer-associated adipocyte transformation

Obesity has emerged as a prominent risk factor for the development of malignant tumors. However, the existing literature on the role of adipocytes in the tumor microenvironment (TME) to elucidate the correlation between obesity and cancer remains insufficient. Here, we aim to investigate the formation of cancer-associated adipocytes (CAAs) and their contribution to tumor growth using mouse models harboring dysfunctional adipocytes. Specifically, we employ adipocyte-specific BECN1 KO (BaKO) mice, which exhibit lipodystrophy due to dysfunctional adipocytes. Our results reveal the activation of YAP/TAZ signaling in both CAAs and BECN1-deficient adipocytes, inducing adipocyte dedifferentiation and formation of a malignant TME. The additional deletion of YAP/TAZ from BaKO mice significantly restores the lipodystrophy and inflammatory phenotypes, leading to tumor regression. Furthermore, mice fed a high-fat diet (HFD) exhibit decreased BECN1 and increased YAP/TAZ expression in their adipose tissues. Treatment with the YAP/TAZ inhibitor, verteporfin, suppresses tumor progression in BaKO and HFD-fed mice, highlighting its efficacy against mice with metabolic dysregulation. Overall, our findings provide insights into the key mediators of CAA and their significance in developing a TME, thereby suggesting a viable approach targeting adipocyte homeostasis to suppress cancer growth.

Tumor cell-intrinsic epigenetic dysregulation shapes cancer-associated fibroblasts heterogeneity to metabolically support pancreatic cancer

The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) involves a significant accumulation of cancer-associated fibroblasts (CAFs) as part of the host response to tumor cells. The origins and functions of transcriptionally diverse CAF populations in PDAC remain poorly understood. Tumor cell-intrinsic genetic mutations and epigenetic dysregulation may reshape the TME; however, their impacts on CAF heterogeneity remain elusive. SETD2, a histone H3K36 trimethyl-transferase, functions as a tumor suppressor. Through single-cell RNA sequencing, we identify a lipid-laden CAF subpopulation marked by ABCA8a in Setd2-deficient pancreatic tumors. Our findings reveal that tumor-intrinsic SETD2 loss unleashes BMP2 signaling via ectopic gain of H3K27Ac, leading to CAFs differentiation toward lipid-rich phenotype. Lipid-laden CAFs then enhance tumor progression by providing lipids for mitochondrial oxidative phosphorylation via ABCA8a transporter. Together, our study links CAF heterogeneity to epigenetic dysregulation in tumor cells, highlighting a previously unappreciated metabolic interaction between CAFs and pancreatic tumor cells.

Lipid droplets provide metabolic flexibility for cancer progression

A hallmark of cancer cells is their remarkable ability to efficiently adapt to favorable and hostile environments. Due to a unique metabolic flexibility, tumor cells can grow even in the absence of extracellular nutrients or in stressful scenarios. To achieve this, cancer cells need large amounts of lipids to build membranes, synthesize lipid-derived molecules, and generate metabolic energy in the absence of other nutrients. Tumor cells potentiate strategies to obtain lipids from other cells, metabolic pathways to synthesize new lipids, and mechanisms for efficient storage, mobilization, and utilization of these lipids. Lipid droplets (LDs) are the organelles that collect and supply lipids in eukaryotes and it is increasingly recognized that the accumulation of LDs is a new hallmark of cancer cells. Furthermore, an active role of LD proteins in processes underlying tumorigenesis has been proposed. Here, by focusing on three major classes of LD-resident proteins (perilipins, lipases, and acyl-CoA synthetases), we provide an overview of the contribution of LDs to cancer progression and discuss the role of LD proteins during the proliferation, invasion, metastasis, apoptosis, and stemness of cancer cells.

TM7SF2-induced lipid reprogramming promotes cell proliferation and migration via CPT1A/Wnt/β-Catenin axis in cervical cancer cells

Cervical cancer poses a serious threat to women's health globally. Our previous studies found that upregulation of TM7SF2, which works as an enzyme involved in the process of cholesterol biosynthesis expression, was highly correlated with cervical cancer. However, the mechanistic basis of TM7SF2 promoting cervical cancer progression via lipid metabolism remains poorly understood. Therefore, quantification of fatty acids and lipid droplets were performed in vitro and in vivo. The protein-protein interaction was verified by Co-IP technique. The mechanism and underlying signaling pathway of TM7SF2 via CPT1A associated lipid metabolism in cervical cancer development were explored using Western blotting, IHC, colony formation, transwell assay, and wound healing assay. This study reported that overexpression of TM7SF2 increased fatty acids content and lipid droplets both in vivo and in vitro experiments. While knockout of TM7SF2 obviously attenuated this process. Moreover, TM7SF2 directly bonded with CPT1A, a key enzyme in fatty acid oxidation, and regulated CPT1A protein expression in cervical cancer cells. Notably, the proliferation and metastasis of cervical cancer cells were elevated when their CPT1A expression was upregulated. Then, rescue assay identified that CPT1A overexpressed could enhance the cell viability and migration in TM7SF2-knockout cells. Furthermore, depletion of TM7SF2 significantly inhibited WNT and β-catenin proteins expression, which was enhanced by CPT1A-overexpressed. The proliferation and migration of cervical cancer cells were reversed in CPT1A-overexpressed cells with the treatment of MSAB, an inhibitor of Wnt/β-Catenin pathway. This study put forward an idea that TM7SF2-induced lipid reprogramming promotes proliferation and migration via CPT1A/Wnt/β-Catenin axis in cervical cancer, underlying the progression of cervical cancer.

Tumoral acidosis promotes adipose tissue depletion by fostering adipocyte lipolysis

OBJECTIVE

Tumour progression drives profound alterations in host metabolism, such as adipose tissue depletion, an early event of cancer cachexia. As fatty acid consumption by cancer cells increases upon acidosis of the tumour microenvironment, we reasoned that fatty acids derived from distant adipose lipolysis may sustain tumour fatty acid craving, leading to the adipose tissue loss observed in cancer cachexia.

METHODS

To evaluate the pro-lipolytic capacities of acid-exposed cancer cells, primary mouse adipocytes from subcutaneous and visceral adipose tissue were exposed to pH-matched conditioned medium from human and murine acid-exposed cancer cells (pH 6.5), compared to naive cancer cells (pH 7.4). To further address the role of tumoral acidosis on adipose tissue loss, a pH-low insertion peptide was injected into tumour-bearing mice, and tumoral acidosis was neutralised with a sodium bicarbonate buffer. Prolipolytic mediators were identified by transcriptomic approaches and validated on murine and human adipocytes.

RESULTS

Here, we reveal that acid-exposed cancer cells promote lipolysis from subcutaneous and visceral adipocytes and that dampening acidosis in vivo inhibits adipose tissue depletion. We further found a set of well-known prolipolytic factors enhanced upon acidosis adaptation and unravelled a role for β-glucuronidase (GUSB) as a promising new actor in adipocyte lipolysis.

CONCLUSIONS

Tumoral acidosis promotes the mobilization of fatty acids derived from adipocytes via the release of soluble factors by cancer cells. Our work paves the way for therapeutic approaches aimed at tackling cachexia by targeting the tumour acidic compartment.

FATP2 activates PI3K/Akt/mTOR pathway by inhibiting ATF3 and promotes the occurrence and development of bladder cancer

Bladder cancer (BLCA) is ranked among the main causes of mortality in male cancer patients, and research into targeted therapies guided by its genomics and molecular biology has been a prominent focus in BLCA studies. Fatty acid transporter protein 2 (FATP2), a member of the FATPs family,is a key contributor to the progression of cancers such as hepatocellular carcinomas and melanomas.However,its role in BLCA remains poorly understand. This study delved into the function of FATP2 in BLCA through a succession of experiments in vivo and in vitro, employing techniques as quantitative real-time polymerase chain reaction (qRT-PCR), RNA sequencing, transwell assays, immunofluorescence, western blot,and others to dissect its mechanistic actions. The findings revealed that an oncogenic function is executed by FATP2 in bladder cancer, significantly impacting the proliferation and migration capabilities, thereby affecting the prognosis of BLCA patients. Furthermore, A suppression that relies on both time and concentration of BLCA proliferation and migration, trigger of apoptosis, and blockage of the cell cycle at the G2/M phase were observed when the inhibitor of FATP2, Lipofermata, was applied. It was unveiled through subsequent investigations that ATF3 expression is indirectly promoted by Lipofermata through the inhibition of FATP2, ultimately inhibiting the signal transduction of the PI3K/Akt/mTOR pathway. This effect was also responsible for the inhibitory impact on BLCA proliferation. Therefore, FATP2 emerges as an auspicious and emerging molecular target with potential applications in precision therapy in BLCA.

Lipid profile in breast cancer: From signaling pathways to treatment strategies

Breast cancer is the most prevalent cancer in women. Metabolic abnormalities, particularly increased lipid synthesis and uptake, impact the onset and progression of the disease. However, the influence of lipid metabolism in breast cancer varies according to the disease stage and patient's hormone status. In postmenopausal patients, obesity is associated with a higher risk and poor prognosis of luminal tumors, while in premenopausal individuals, it is correlated to BRCA mutated tumors. In fact, the tumor's lipid profile may be used to distinguish between HER2+, luminal and BRCA-mutated tumors. Moreover, drug resistance was associated with increased fatty acid synthesis and alterations in membrane composition, impacting its fluidity and spatial subdomains such as lipid rafts. Here, we discuss the subtype-specific lipid metabolism alterations found in breast cancer and the potentiality of its modulation in a clinical setting.

White adipocyte dysfunction and obesity-associated pathologies in humans

The prevalence of obesity and associated chronic diseases continues to increase worldwide, negatively impacting on societies and economies. Whereas the association between excess body weight and increased risk for developing a multitude of diseases is well established, the initiating mechanisms by which weight gain impairs our metabolic health remain surprisingly contested. In order to better address the myriad of disease states associated with obesity, it is essential to understand adipose tissue dysfunction and develop strategies for reinforcing adipocyte health. In this Review we outline the diverse physiological functions and pathological roles of human white adipocytes, examining our current knowledge of why white adipocytes are vital for systemic metabolic control, yet poorly adapted to our current obesogenic environment.

Targeting endogenous fatty acid synthesis stimulates the migration of ovarian cancer cells to adipocytes and promotes the transport of fatty acids from adipocytes to cancer cells

Despite significant advances in oncology, 1 of 108 female patients succumb to ovarian cancer (OC) each year. Improved novel treatments against this aggressive disease would be a major improvement. The growth of OC cells has been demonstrated to be highly dependent on lipids. OC cells are abundantly present in the abdominal cavity and omentum, the main sites of OC expansion. Accordingly, it has been attempted not only to block the hyperactive synthesis of fatty acids (FAs) in cancer cells, but also to disrupt lipid supply. While either strategy has yielded promising results as monotherapy, the induction of resistance pathways diminishing the anticancer effects is yet conceivable. The endogenous regulation of lipid biosynthesis in OC has been extensively studied. However, the role of stromal cells in the modulation of the effects of anti‑lipogenic drugs has not yet been well documented. The present study thus examined the interaction between OC cells and associated stromal cells, when de novo FA synthesis was blocked. It has recently been revealed by the authors that when FA are provided to OC cells in monoculture, the lipid deficiency induced by pharmacological inhibition of FA synthase (FASN), the key enzyme of endogenous FA synthesis, cannot be compensated through an increased FA uptake by OC cells. In the present study, OC cells were co‑cultured with adipocytes preloaded with fluorescent FA and the effects of FASN‑inhibition on OC homing to adipocytes and the transcellular delivery of fluorescent FA from adipocytes to OC cells were examined. The FASN inhibitors, G28UCM and Fasnall, stimulated the spontaneous migration of A2780 OC cells in a concentration‑dependent manner and stimulated the transfer of FA from adipocytes to OC cells. Similar effects were observed with all types of adipocytes tested. The models applied in the present study demonstrated that co‑cultured cancer‑associated adipocytes may attenuate the anticancer effects of FASN inhibitors by attracting tumor cells and by supplying the cells with FA. This lipid‑mediated dependency may provide a rationale for the design of new treatment approaches for the treatment of OC.

Emerging Futuristic Targeted Therapeutics: A Comprising Study Towards a New Era for the Management of TNBC

Triple-negative breast cancer is characterized by high lethality attributed to factors such as chemoresistance, transcriptomic, and genomic heterogeneity, leading to a poor prognosis and limiting available targeted treatment options. While the identification of molecular targets remains pivotal for therapy involving chemo drugs, the current challenge lies in the poor response rates, low survival rates, and frequent relapses. Despite various clinical investigations exploring molecular targeted therapies in conjunction with conventional chemo treatment, the outcomes have been less than optimal. The critical need for more effective therapies underscores the urgency to discover potent novel treatments, including molecular and immune targets, as well as emerging strategies. This review provides a comprehensive analysis of conventional treatment approaches and explores emerging molecular and immune-targeted therapeutics, elucidating their mechanisms to address the existing obstacles for a more effective management of triple-negative breast cancer.

FAM3C in Cancer-Associated Adipocytes Promotes Breast Cancer Cell Survival and Metastasis

Adipose tissue within the tumor microenvironment (TME) plays a critical role in supporting breast cancer progression. In this study, we identified FAM3 metabolism-regulating signaling molecule C (FAM3C) produced by cancer-associated adipocytes (CAA) as a key regulator of tumor progression. FAM3C overexpression in cultured adipocytes significantly reduced cell death in both adipocytes and cocultured breast cancer cells while suppressing markers of fibrosis. Conversely, FAM3C depletion in CAAs resulted in adipocyte-mesenchymal transition (AMT) and increased fibrosis within the TME. Adipocyte FAM3C expression was driven by TGFβ signaling from breast cancer cells and was reduced upon treatment with a TGFβ-neutralizing antibody. FAM3C knockdown in CAAs early in tumorigenesis in a genetically engineered mouse model of breast cancer significantly inhibited primary and metastatic tumor growth. Circulating FAM3C levels were elevated in patients with metastatic breast cancer compared with those with nonmetastatic breast cancer. These results suggest that therapeutic inhibition of FAM3C expression levels in CAAs during early tumor development could be a promising approach in the treatment of patients with breast cancer.

SIGNIFICANCE

High FAM3C levels in cancer-associated adipocytes contribute to tumor-supportive niches and are tightly associated with metastatic growth, indicating that FAM3C inhibition could be beneficial for treating patients with breast cancer.

Hsa_circ_0021205 enhances lipolysis via regulating miR-195-5p/HSL axis and drives malignant progression of glioblastoma

Abnormal lipid metabolism is an essential hallmark of glioblastoma. Hormone sensitive lipase (HSL), an important rate-limiting enzyme contributed to lipolysis, which was involved in aberrant lipolysis of glioblastoma, however, its definite roles and the relevant regulatory pathway have not been fully elucidated. Our investigations disclosed high expression of HSL in glioblastoma. Knock-down of HSL restrained proliferation, migration, and invasion of glioblastoma cells while adding to FAs could significantly rescue the inhibitory effect of si-HSL on tumor cells. Overexpression of HSL further promoted tumor cell proliferation and invasion. Bioinformatics analysis and dual-luciferase reporter assay were performed to predict and verify the regulatory role of ncRNAs on HSL. Mechanistically, hsa_circ_0021205 regulated HSL expression by sponging miR-195-5p, which further promoted lipolysis and drove the malignant progression of glioblastoma. Besides, hsa_circ_0021205/miR-195-5p/HSL axis activated the epithelial-mesenchymal transition (EMT) signaling pathway. These findings suggested that hsa_circ_0021205 promoted tumorigenesis of glioblastoma through regulation of HSL, and targeting hsa_circ_0021205/miR-195-5p/HSL axis can serve as a promising new strategy against glioblastoma.

Phenotype-specific melanoma uptake of fatty acid from human adipocytes activates AXL and CAV1-dependent β-catenin nuclear accumulation

Phenotypic diversity of cancer cells within tumors generated through bi-directional interactions with the tumor microenvironment has emerged as a major driver of disease progression and therapy resistance. Nutrient availability plays a critical role in determining phenotype, but whether specific nutrients elicit different responses on distinct phenotypes is poorly understood. Here we show, using melanoma as a model, that only MITF Low undifferentiated cells, but not MITF High cells, are competent to drive lipolysis in human adipocytes. In contrast to MITF High melanomas, adipocyte-derived free fatty acids are taken up by undifferentiated MITF Low cells via a fatty acid transporter (FATP)-independent mechanism. Importantly, oleic acid (OA), a monounsaturated long chain fatty acid abundant in adipose tissue and lymph, reprograms MITF Low undifferentiated melanoma cells to a highly invasive state by ligand-independent activation of AXL, a receptor tyrosine kinase associated with therapy resistance in a wide range of cancers. AXL activation by OA then drives SRC-dependent formation and nuclear translocation of a β-catenin-CAV1 complex. The results highlight how a specific nutritional input drives phenotype-specific activation of a pro-metastasis program with implications for FATP-targeted therapies.