Obesity-induced changes in cancer cells and their microenvironment: Mechanisms and therapeutic perspectives to manage dysregulated lipid metabolism

The impact of the tumor microenvironment in the dual burden of obesity-cancer link

Obesity induces systemic perturbations of tissue homeostasis, leading to dyslipidemia, insulin resistance and chronic state of inflammation. Evidence from clinical and preclinical studies links excess of adiposity with increased cancer incidence and suggests that chronic inflammation may contribute to increased cancer risk in obese patients. Over the last decades of obesity research, multifaced and complicated effects of abnormal or excessive expansion of Adipose Tissue have been uncovered. In particular, it is widely described how obesity can exacerbate the tumorigenesis for instance by fueling soluble signals and adipokines and by enhancing tissue inflammation and altering the hormonal balance. Less is known about the paracrine effects of the cancer-associated adipocytes on the tumor cells and still poorly explored is the reciprocal communication between cancer cells and the adipose component of the tumor microenvironment (TME). In this review, we will address the mechanisms by which the peritumoral Adipose Tissue can influence the dynamics of tumoral cells. We will discuss how obesity-induced changes in the tumor microenvironment may enhance tumor growth and aggressive characteristics leading to increased invasiveness and metastatic progression of cancer that leads to a worsen cancer survival in obese subjects. We conclude that targeting the peritumoral adipose component of the TME would be a therapeutic option to prevent cancer development.

Targeting lipid metabolism: novel insights and therapeutic advances in pancreatic cancer treatment

Lipid metabolism in cancer is characterized by dysregulated lipid regulation and utilization, critical for promoting tumor growth, survival, and resistance to therapy. Pancreatic cancer (PC) is a highly aggressive malignancy of the gastrointestinal tract that has a dismal 5-year survival rate of less than 10%. Given the essential function of the pancreas in digestion, cancer progression severely disrupts its function. Standard treatments for PC such as surgical resection, chemotherapy, and radiotherapy. However, these therapies often face significant challenges, including biochemical recurrence and drug resistance.Given these limitations, new therapeutic approaches are being developed to target tumor metabolism. Dysregulation of cholesterol biosynthesis and alterations in fatty acids (FAs), such as palmitate, stearate, omega-3, and omega-6, have been observed in pancreatic cancer. These lipids serve as energy sources, signaling molecules, and essential components of cell membranes. Their accumulation fosters an immunosuppressive tumor microenvironment that supports cancer cell proliferation and metastasis.Moreover, lipid metabolism dysregulation within immune cells, particularly T cells, impairs immune surveillance and weakens the body's defenses against cancer. Abnormal lipid metabolism also contributes to drug resistance in PC. Despite these challenges, targeting lipid metabolism may offer a promising therapeutic strategy. By enhancing lipid peroxidation, the induction of ferroptosis-a form of regulated cell death-could impair the survival of PC cells and hinder disease progression.

The evolving tumor-associated adipose tissue microenvironment in breast cancer: from cancer initiation to metastatic outgrowth

Adipocytes represent a significant proportion of breast tissue, comprising between 3.7 and 37% of stromal tissue. They play a pivotal role in metabolic regulation, energy supply, metabolic regulation, support effects, and cytokine release within the breast. In breast cancer (BC) tissue, adipocytes engage in intricate crosstalk with BC cells, playing a key role in tumor proliferation, invasion, metastasis formation, and metabolic remodeling. This is due to the provision of hormones, adipokines, and fatty acids to tumor cells by the adipocytes. With the initiation of metastatic outgrowth of BC, the peritumoral adipose tissue exhibits abundant and intricate changes based on its original construction and function, which convert it into a tumor-associated adipose tissue microenvironment (TAAME). It includes some specific adipocytes: adipose-derived stem cells (ASCs), cancer-associated adipocytes (CAAs), adipocyte-derived fibroblasts (ADFs), etc. From a mechanistic standpoint, specific adipocytes can facilitate the proliferation, invasion, metastasis, and angiogenesis of BC cells by secreting a multitude of cytokines (IL-6) and adipokines (leptin), which collectively create an environment conducive to BC progression. It is of paramount importance to recognize the TAAME as a crucial target for the diagnosis, treatment, and drug resistance of BC. Consequently, the review presents an overview of the characteristics and interactions of specific adipocytes within TAAME cell populations. This will facilitate the development of more effective personalized therapies against BC progression, relapse, and metastasis.

Blood lipid metabolic biomarkers are emerging as significant prognostic indicators for survival in cancer patients

BACKGROUND

Dyslipidemia is a common comorbidity in patients with cancer, yet the impact of abnormal lipid levels on tumor prognosis remains contentious. This study was conducted to synthesize the current evidence regarding the prognostic utility of blood lipid levels, including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), apolipoprotein A1 (ApoA1), and apolipoprotein B (ApoB), in predicting overall survival (OS) and disease-free survival (DFS) in cancer patients.

METHODS

A comprehensive literature search was performed across electronic databases to assess the associations between blood lipid levels and OS or DFS in cancer patients. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to analyze the data. The research protocol was previously submitted to the International Prospective Register of Systematic Reviews (PROSPERO): CRD42023458597.

RESULTS

Our study represents the largest and most extensive evaluation of the prognostic significance of blood lipid levels in cancer to date. It includes a meta-analysis of 156 eligible studies involving 85,173 cancer patients. The findings revealed a significant association between elevated levels of HDL-C, TC, and ApoA1 and improved OS and DFS in cancer patients. In contrast, no significant relationships were identified between LDL-C, TG, and ApoB levels and the OS or DFS of cancer patients.

CONCLUSION

Blood lipids, particularly HDL-C, TC, and ApoA1, emerge as accessible and cost-effective biomarkers that may aid in assessing survival outcomes in cancer patients and potentially inform clinical decision-making.

Obesity-Related Inflammation Reduces Treatment Sensitivity and Promotes Aggressiveness in Luminal Breast Cancer Modulating Oxidative Stress and Mitochondria

BACKGROUND

Obesity, characterized by the secretion of several pro-inflammatory cytokines and hormones, significantly increases the risk of developing breast cancer and is associated with poorer outcomes. Mitochondrial and antioxidant status are crucial in both tumor progression and treatment response.

METHODS

This study investigates the impact of an ELIT cocktail (17β-estradiol, leptin, IL-6, and TNFα), which simulates the obesity-related inflammation condition in postmenopausal women, using a 3D culture model. We examined the effects of ELIT exposure on mammosphere formation, oxidative stress and mitochondrial markers, and treatment sensitivity in luminal (T47D, MCF7) and triple-negative (MDA-MB-231) breast cancer cell lines. After that, 3D-derived cells were re-cultured under adherent conditions focusing on the mechanisms leading to dissemination and drug sensitivity.

RESULTS

Our results indicated that ELIT condition significantly increased mammosphere formation in luminal breast cancer cell lines (from 3.26% to 6.38% in T47D cell line and 0.68% to 2.32% in MCF7 cell line) but not in the triple-negative MDA-MB-231 cell line. Further analyses revealed a significant decrease in mitochondrial and antioxidant-related markers, particularly in the T47D cell line, where higher levels of ESR2, three-fold increased by ELIT exposure, may play a critical role. Importantly, 3D-derived T47D cells exposed to ELIT showed reduced sensitivity to tamoxifen and paclitaxel, avoiding a 34.2% and 75.1% reduction in viability, respectively. Finally, through in silico studies, we identified specific biomarkers, including TOMM20, NFE2L2, CAT, and ESR2, correlated with poor prognosis in luminal breast cancer.

CONCLUSIONS

Taken together, our findings suggest that antioxidant and mitochondrial markers are key factors that reduce treatment sensitivity in obesity-related luminal breast cancer. The identified biomarkers may serve as valuable tools for the prognosis and development of more effective therapies in these patients.

Characteristics of Abdominal Fat Based on CT Measurements to Predict Early Recurrence After Initial Surgery of NMIBC in Stage Ta/T1

INTRODUCTION

This study aimed to assess the predictive value of abdominal fat characteristics measured by computed tomography (CT) in identifying early recurrence within one year post-initial transurethral resection of bladder tumor (TURBT) in patients with nonmuscle-invasive bladder cancer (NMIBC). A predictive model integrating fat features and clinical factors was developed to guide individualized treatment.

MATERIALS AND METHODS

A retrospective analysis of 203 NMIBC patients from two medical centers was conducted. Abdominal CT images were analyzed using 3D Slicer software. Spearman correlation, logistic regression, and the Lasso algorithm were employed for data analysis. Predictive efficacy was assessed using the area under the curve (AUC) of receiver operating characteristic (ROC) and decision curve analysis (DCA). Calibration was evaluated using the Hosmer-Lemeshow test.

RESULTS

Significant differences in abdominal fat characteristics were found between the recurrence and nonrecurrence groups. All fat features positively correlated with body mass index (BMI), with bilateral perirenal fat thickness (PrFT) showing superior predictive performance. Multivariate logistic regression identified independent predictors of early recurrence, including tumor number, early perfusion chemotherapy, left and right PrFT, and visceral fat area (VFA) at umbilical and renal hilum levels. The Lasso-based model achieved an AUC of 0.904, outperforming existing models.

CONCLUSION

Abdominal fat characteristics, especially bilateral PrFT, strongly correlate with early recurrence in NMIBC. The Lasso-based model, integrating fat and clinical factors, offers superior predictive efficacy and could improve individualized treatment strategies.

Cancer treatments as paradoxical catalysts of tumor awakening in the lung

Much of the fatality of tumors is linked to the growth of metastases, which can emerge months to years after apparently successful treatment of primary tumors. Metastases arise from disseminated tumor cells (DTCs), which disperse through the body in a dormant state to seed distant sites. While some DTCs lodge in pre-metastatic niches (PMNs) and rapidly develop into metastases, other DTCs settle in distinct microenvironments that maintain them in a dormant state. Subsequent awakening, induced by changes in the microenvironment of the DTC, causes outgrowth of metastases. Hence, there has been extensive investigation of the factors causing survival and subsequent awakening of DTCs, with the goal of disrupting these processes to decrease cancer lethality. We here provide a detailed overview of recent developments in understanding of the factors controlling dormancy and awakening in the lung, a common site of metastasis for many solid tumors. These factors include dynamic interactions between DTCs and diverse epithelial, mesenchymal, and immune cell populations resident in the lung. Paradoxically, among key triggers for metastatic outgrowth, lung tissue remodeling arising from damage induced by the treatment of primary tumors play a significant role. In addition, growing evidence emphasizes roles for inflammation and aging in opposing the factors that maintain dormancy. Finally, we discuss strategies being developed or employed to reduce the risk of metastatic recurrence.

Effect of genistein supplementation on microenvironment regulation of breast tumors in obese mice

Obesity is an important risk factor for breast cancer in women before and after menopause. Adipocytes, key mediators in the tumor microenvironment, play a pivotal role in the relationship between obesity with cancer. However, the potential of dietary components in modulating this relationship remains underexplored. Genistein, a soy-derived isoflavone, has shown promise in reducing breast cancer risk, attenuating obesity-associated inflammation, and improving insulin resistance. However, there are no reports examining whether genistein has the ability to reduce the effects of obesity on breast tumor development. In this study, we constructed a mammary tumor model in ovariectomized obese mice and examined the effects of genistein on body condition and tumor growth. Moreover, the effects of genistein on the tumor microenvironment were examined via experimental observation of peritumoral adipocytes and macrophages. In addition, we further investigated the effect of genistein on adipocyte and breast cancer cell crosstalk via coculture experiments. Our findings indicate that dietary genistein significantly alleviates obesity, systemic inflammation, and metabolic disorders induced by a high-fat diet in ovariectomized mice. Notably, it also inhibits tumor growth in vivo. The impact of genistein extends to the tumor microenvironment, where it reduces the production of cancer-associated adipocytes (CAAs) and the recruitment of M2d-subtype macrophages. In vitro, genistein mitigates the transition of adipocytes into CAAs and inhibits the expression of inflammatory factors by activating PPAR-γ pathway and degrading nuclear NF-κB. Furthermore, it impedes the acquisition of invasive properties and epithelial‒mesenchymal transition in breast cancer cells under CAA-induced inflammation, disrupting the Wnt3a/β-catenin pathway. Intriguingly, the PPAR-γ inhibitor T0070907 counteracted the effects of genistein in the coculture system, underscoring the specificity of its action. Our study revealed that genistein can mitigate the adverse effects of obesity on breast cancer by modulating the tumor microenvironment. These findings provide new insights into how genistein intake and a soy-based diet can reduce breast cancer risk.

Role of carboxylesterase and arylacetamide deacetylase in drug metabolism, physiology, and pathology

Carboxylesterases (CES1 and CES2) and arylacetamide deacetylase (AADAC), which are expressed primarily in the liver and/or gastrointestinal tract, hydrolyze drugs containing ester and amide bonds in their chemical structure. These enzymes often catalyze the conversion of prodrugs, including the COVID-19 drugs remdesivir and molnupiravir, to their pharmacologically active forms. Information on the substrate specificity and inhibitory properties of these enzymes, which would be useful for drug development and toxicity avoidance, has accumulated. Recently,in vitroandin vivostudies have shown that these enzymes are involved not only in drug hydrolysis but also in lipid metabolism. CES1 and CES2 are capable of hydrolyzing triacylglycerol, and the deletion of their orthologous genes in mice has been associated with impaired lipid metabolism and hepatic steatosis. Adeno-associated virus-mediated human CES overexpression decreases hepatic triacylglycerol levels and increases fatty acid oxidation in mice. It has also been shown that overexpression of CES enzymes or AADAC in cultured cells suppresses the intracellular accumulation of triacylglycerol. Recent reports indicate that AADAC can be up- or downregulated in tumors of various organs, and its varied expression is associated with poor prognosis in patients with cancer. Thus, CES and AADAC not only determine drug efficacy and toxicity but are also involved in pathophysiology. This review summarizes recent findings on the roles of CES and AADAC in drug metabolism, physiology, and pathology.

Adenosine-modulating synthetic high-density lipoprotein for chemoimmunotherapy of triple-negative breast cancer

Adenosine (ADO) is a common chemotherapy-associated immune checkpoint that hinders anti-tumor immunity-mediated efficacy of chemotherapy. Herein, we created a synthetic high-density lipoprotein (sHDL) by co-assembly of a doxorubicin (DOX)-apolipoprotein A1 mimetic peptide conjugate, PSB-603 (an A2BR inhibitor), phospholipid, and cholesterol oleate with a microfluidic-based method. The obtained DP-sHDL showed a self-promoted drug delivery to cancer cells via remodeling tumor microenvironment. DP-sHDL could trigger the release of ATP from cancer cells and inhibit its conversion into ADO. Consequently, DP-sHDL, while increasing immunogenic cell death, reduced intratumoral ADO levels by 58%. This treatment improved both the density and activity of CD8+ T cells as well as NK cells and relieved the immunosuppressive microenvironment, and led to a substantial inhibition of 4T1 tumor growth, thereby extending the survival of mice. The efficacy of DP-sHDL could be further improved when used in combination with immune checkpoint blockade therapy. We envision that this platform provides a simple yet promising strategy to enhance anti-tumor response of chemotherapy by relieving treatment-associated immunosuppression.

Prevalence, associated factors, and gene polymorphisms of obesity in Tibetan adults in Qinghai, China

OBJECTIVES

To explore the prevalence and associated factors of obesity in Tibetan adults in Qinghai, China, and to determine the association between the FTO (rs1121980 and rs17817449) and MC4R gene (rs17782313 and rs12970134) polymorphisms with obesity.

METHODS

A cross-sectional survey was conducted in 2015 in Qinghai to selected Tibetan adults aged 20 to 80 years. Prevalence of obesity (BMI ≥ 28 kg/m2) and overweight (BMI 24 ~ 27.9 kg/m2) were evaluated. Multivariable logistic models were used to determine the associated factors. Pair-matched subjects of obesity cases and normal-weight controls were selected for the gene polymorphism analyses. Conditional logistic models were used to assess the association between gene polymorphisms with obesity. Additive and multiplicative gene-environment interactions were tested.

RESULTS

A total of 1741 Tibetan adults were enrolled. The age- and sex- standardized prevalence of obesity and overweight was 18.09% and 31.71%, respectively. Male sex, older age, heavy level of leisure-time exercise, current smoke, and heavy level of occupational physical activity were associated with both obesity and overweight. MC4R gene polymorphisms were associated with obesity in Tibetan adults. No significant gene-environment interaction was detected.

CONCLUSION

The prevalence of obesity and overweight in Tibetan adults was high. Both environmental and genetic factors contributed to the obesity prevalent.

Multifaceted effects of obesity on cancer immunotherapies: Bridging preclinical models and clinical data

Obesity, defined by excessive body fat, is a highly complex condition affecting numerous physiological processes, such as metabolism, proliferation, and cellular homeostasis. These multifaceted effects impact cells and tissues throughout the host, including immune cells as well as cancer biology. Because of the multifaceted nature of obesity, common parameters used to define it (such as body mass index in humans) can be problematic, and more nuanced methods are needed to characterize the pleiotropic metabolic effects of obesity. Obesity is well-accepted as an overall negative prognostic factor for cancer incidence, progression, and outcome. This is in part due to the meta-inflammatory and immunosuppressive effects of obesity. Immunotherapy is increasingly used in cancer therapy, and there are many different types of immunotherapy approaches. The effects of obesity on immunotherapy have only recently been studied with the demonstration of an "obesity paradox", in which some immune therapies have been demonstrated to result in greater efficacy in obese subjects despite the direct adverse effects of obesity and excess body fat acting on the cancer itself. The multifactorial characteristics that influence the effects of obesity (age, sex, lean muscle mass, underlying metabolic conditions and drugs) further confound interpretation of clinical data and necessitate the use of more relevant preclinical models mirroring these variables in the human scenario. Such models will allow for more nuanced mechanistic assessment of how obesity can impact, both positively and negatively, cancer biology, host metabolism, immune regulation, and how these intersecting processes impact the delivery and outcome of cancer immunotherapy.

Salacia reticulata Extract Suppresses Fat Accumulation by Regulating Lipid Metabolism

The excessive storage of triglycerides in adipose tissue is a characteristic feature of obesity, which arises from an imbalance between energy intake and expenditure. In this study, we aimed to explore the potential anti-obesity effects of Salacia reticulata extracts (SC) in a high-fat diet (HFD)-induced in obese mice and 3T3-L1 adipocytes, with a specific focus on understanding the underlying lipid mechanisms. Mice were fed with a normal diet (NC; normal control), HFD (60% high-fat diet), Met (HFD containing metformin 250 mg/kg b.w.), SC25 (HFD containing SC 25 mg/kg b.w.), SC50 (HFD containing SC 50 mg/kg b.w.), or SC 100 (HFD containing SC 100 mg/kg b.w.) for 12 weeks. Notably, SC supplementation led to significant reductions in body weight gain, adipose tissue weight, adipose tissue mass, and adipocyte size in HFD-fed mice. Furthermore, SC supplementation exerted inhibitory effects on the adipogenesis and lipogenesis pathways while promoting lipolysis and thermogenesis pathways in the adipose tissues of HFD-fed mice. In vitro experiments using 3T3-L1 cells demonstrated that SC treatment during the differentiation phase suppressed adipogenesis and lipogenesis, whereas SC treatment after differentiation, activated lipolysis and thermogenesis. Collectively, these findings indicate that SC exhibits a direct influence on the lipid metabolism of adipocytes, making it an effective candidate for weight loss interventions.