Obesity and Cancer: 27-Hydroxycholesterol, the Missing Link

Effects of dietary intervention on human diseases: molecular mechanisms and therapeutic potential

Diet, serving as a vital source of nutrients, exerts a profound influence on human health and disease progression. Recently, dietary interventions have emerged as promising adjunctive treatment strategies not only for cancer but also for neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions have demonstrated substantial potential in modulating metabolism, disease trajectory, and therapeutic responses. Metabolic reprogramming is a hallmark of malignant progression, and a deeper understanding of this phenomenon in tumors and its effects on immune regulation is a significant challenge that impedes cancer eradication. Dietary intake, as a key environmental factor, can influence tumor metabolism. Emerging evidence indicates that dietary interventions might affect the nutrient availability in tumors, thereby increasing the efficacy of cancer treatments. However, the intricate interplay between dietary interventions and the pathogenesis of cancer and other diseases is complex. Despite encouraging results, the mechanisms underlying diet-based therapeutic strategies remain largely unexplored, often resulting in underutilization in disease management. In this review, we aim to illuminate the potential effects of various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet, on cancer and the aforementioned diseases. We explore the multifaceted impacts of these dietary interventions, encompassing their immunomodulatory effects, other biological impacts, and underlying molecular mechanisms. This review offers valuable insights into the potential application of these dietary interventions as adjunctive therapies in disease management.

27-Hydroxycholesterol inhibits trophoblast fusion during placenta development by activating PI3K/AKT/mTOR signaling pathway

Trophoblast cell syncytialization is essential for placental and fetal development. Abnormal trophoblast cell fusion leads to pregnancy pathologies, such as preeclampsia (PE), intrauterine growth restriction (IUGR), and miscarriage. 27-hydroxycholesterol (27-OHC) is the most abundant oxysterol in human peripheral blood synthesized by sterol 27-hydroxylase (CYP27A1) and is considered a critical mediator between hypercholesterolemia and a variety of related disorders. Gestational hypercholesterolemia was associated with spontaneous preterm delivery and low birth weight (LBW) in term infants, yet the mechanism is unclear. In this study, two trophoblast cell models and CD-1 mice were used to evaluate the effects of 27-OHC on trophoblast fusion during placenta development. Two different kinds of trophoblast cells received a dosage of 2.5, 5, or 10 uM 27-OHC. Three groups of pregnant mice were randomly assigned: control, full treatment (E0.5-E17.5), or late treatment (E13.5-E17.5). All mice received daily intraperitoneal injections of saline (control group) and 27-OHC (treatment group; 5.5 mg/kg). In vitro experiments, we found that 27-OHC inhibited trophoblast cell fusion in primary human trophoblasts (PHT) and forskolin (FSK)-induced BeWo cells. 27-OHC up-regulated the expression of the PI3K/AKT/mTOR signaling pathway-related proteins. Moreover, the PI3K inhibitor LY294002 rescued the inhibitory effect of 27-OHC. Inhibition of trophoblast cell fusion by 27-OHC was also observed in CD-1 mice. Furthermore, fetal weight and placental efficiency decreased and fetal blood vessel development was inhibited in pregnant mice treated with 27-OHC. This study was the first to prove that 27-OHC inhibits trophoblast cell fusion by Activating PI3K/AKT/mTOR signaling pathway. This study reveals a novel mechanism by which dyslipidemia during pregnancy results in adverse pregnancy outcomes.

The role of 27-hydroxycholesterol in meta-inflammation

27-Hydroxycholesterol (27OHChol), a prominent cholesterol metabolite present in the bloodstream and peripheral tissues, is a kind of immune oxysterol that elicits immune response. Recent research indicates the involvement of 27OHChol in metabolic inflammation (meta-inflammation) characterized by chronic responses associated with metabolic irregularities. 27OHChol activates monocytic cells such that they secrete pro-inflammatory cytokines and chemokines, and increase the expression of cell surface molecules such as pattern-recognition receptors that play key roles in immune cell-cell communication and sensing metabolism-associated danger signals. Levels of 27OHChol increase when cholesterol metabolism is disrupted, and the resulting inflammatory responses can contribute to the development and complications of metabolic syndrome, including obesity, insulin resistance, and cardiovascular diseases. Since 27OHChol can induce chronic immune response by activating monocyte-macrophage lineage cells that play a crucial role in meta-inflammation, it is essential to understand the 27OHChol-induced inflammatory responses to unravel the roles and mechanisms of action of this cholesterol metabolite in chronic metabolic disorders.

Urolithin A: A promising selective estrogen receptor modulator and 27-hydroxycholesterol attenuator in breast cancer

27-hydroxycholesterol (27-HC) is an oxysterol that acts as an endogenous selective estrogen receptor modulator (SERM), and its adverse effects on breast cancer via the estrogen receptor (ER) have provided new insights into the pathology of cholesterol-linked breast cancer. Our earlier in vitro experiments showed that the methanolic extract of pomegranate could exhibit SERM properties and compete with 27-HC. The major constituents of pomegranate are ellagitannins and ellagic acid, which are converted into urolithins by the colonic microbiota. In recent years, urolithins, especially urolithin A (UA) and urolithin B (UB), have been reported to have a plethora of advantageous effects, including antiproliferative and estrogenic activities. In this study, we attempted to determine the potential of urolithins in antagonizing and counteracting the adverse effects of 27-HC in breast cancer cells. Our findings suggested that UA had an antiproliferative capacity and attenuated the proliferative effects of 27-HC, resulting in subsequent loss of membrane potential and apoptosis in breast cancer cells. Further, UA induced estrogen response element (ERE) transcriptional activity and modulated estrogen-responsive genes, exhibiting a SERM-like response concerning receptor binding. Our in vivo hollow fiber assay results showed a loss of cell viability in breast cancer cells upon UA consumption, as well as a reduction in 27-HC-induced proliferative activity. Additionally, it was shown that UA did not induce uterine proliferation or alter blood biochemical parameters. Based on these findings, we can conclude that UA has the potential to act as a potent estrogen receptor alpha (ERα) modulator and 27-HC antagonist. UA is safe to consume and is very well tolerated. This study further opens up the potential of UA as ER modulator and its benefits in estrogen-dependent tissues.

27-Hydroxycholesterol represses G9a expression via oestrogen receptor alpha in breast cancer

27-hydroxycholesterol (27-HC) is a cholesterol metabolite and the first discovered endogenous selective estrogen receptor modulator (SERM) that has been shown to have proliferative and metastatic activity in breast cancer. However, whether 27-HC metabolite modulates the epigenetic signatures in breast cancer and its progression remains unclear. The current study, reports that 27-HC represses the expression of euchromatic histone lysine methyltransferase G9a, further reducing di-methylation at H3K9 in a subset of genes. We also observed reduced occupancy of ERα at the G9a promoter, indicating that 27-HC negatively regulates the ERα occupancy on the G9a promoter and functions as a transcriptional repressor. Further, ChIP-sequencing for the H3K9me2 mark has demonstrated that 27-HC treatment reduces the H3K9me2 mark on subset of genes linked to cancer progression, proliferation, and metastasis. We observed upregulation of these genes following 27-HC treatment which further confirms the loss of methylation at these genes. Immunohistochemical analysis with breast cancer patient tissues indicated a positive correlation between G9a expression and CYP7B1, a key enzyme of 27-HC catabolism. Overall, this study reports that 27-HC represses G9a expression via ERα and reduces the levels of H3K9me2 on a subset of genes, including the genes that aid in breast tumorigenesis and invasion further, increasing its expression in the breast cancer cells.

Circulating 27-hydroxycholesterol, lipids, and steroid hormones in breast cancer risk: a nested case-control study of the Multiethnic Cohort Study

BACKGROUND

Laboratory studies have indicated that a cholesterol metabolite and selective estrogen receptor modulator, 27-hydroxycholesterol (27HC), may be important in breast cancer etiology and explain associations between obesity and postmenopausal breast cancer risk. Epidemiologic evidence for 27HC in breast cancer risk is limited, particularly in multiethnic populations.

METHODS

In a nested case-control study of 1470 breast cancer cases and 1470 matched controls within the Multiethnic Cohort Study, we examined associations of pre-diagnostic circulating 27HC with breast cancer risk among African American, Japanese American, Native Hawaiian, Latino, and non-Latino White postmenopausal females. We used multivariable logistic regression adjusted for age, education, parity, body mass index, and smoking status. Stratified analyses were conducted across racial and ethnic groups, hormone receptor (HR) status, and use of lipid-lowering drugs. We assessed interactions of 27HC with steroid hormones.

RESULTS

27HC levels were inversely related to breast cancer risk (odds ratio [OR] 0.80; 95% confidence interval [CI] 0.58, 1.12), but the association was not statistically significant in the full model. Directions of associations differed by racial and ethnic group. Results suggested an inverse association with HR-negative breast cancer (OR 0.46; 95% CI 0.20, 1.06). 27HC interacted with testosterone, but not estrone, on risk of breast cancer; 27HC was only inversely associated with risk among those with the highest levels of testosterone (OR 0.46; 95% CI 0.24, 0.86).

CONCLUSION

This is the first US study to examine circulating 27HC and breast cancer risk and reports a weak inverse association that varies across racial and ethnic groups and testosterone level.

Diet as a modifiable factor in tumorigenesis: Focus on microbiome-derived bile acid metabolites and short-chain fatty acids

Several lines of evidences have implicated the resident microbiome as a key factor in the modulation of host physiology and pathophysiology; including the resistance to cancers. Gut microbiome heavily influences host lipid homeostasis by their modulatory effects on the metabolism of bile acids (BAs). Microbiota-derived BA metabolites such as deoxycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) are implicated in the pathogeneses of various cancer types. The pathogenic mechanisms are multimodal in nature, with widespread influences on the host immunes system, cell survival and growth signalling and DNA damage. On the other hand, short-chain fatty acids (SCFAs) produced by the resident microbial activity on indigestible dietary fibres as well as during intermittent fasting regimens (such as the Ramazan fasting) elicit upregulation of the beneficial anti-inflammatory and anticancer pathways in the host. The present review first provides a brief overview of the molecular mechanisms of microbiota-derived lipid metabolites in promotion of tumour development. The authors then discuss the potential of diet as a therapeutic route for beneficial alteration of microbiota and the consequent changes in the production of SCFAs, particularly butyrate, in relation to the cancer prevention and treatment.

Exhaustion-associated cholesterol deficiency dampens the cytotoxic arm of antitumor immunity

The concept of targeting cholesterol metabolism to treat cancer has been widely tested in clinics, but the benefits are modest, calling for a complete understanding of cholesterol metabolism in intratumoral cells. We analyze the cholesterol atlas in the tumor microenvironment and find that intratumoral T cells have cholesterol deficiency, while immunosuppressive myeloid cells and tumor cells display cholesterol abundance. Low cholesterol levels inhibit T cell proliferation and cause autophagy-mediated apoptosis, particularly for cytotoxic T cells. In the tumor microenvironment, oxysterols mediate reciprocal alterations in the LXR and SREBP2 pathways to cause cholesterol deficiency of T cells, subsequently leading to aberrant metabolic and signaling pathways that drive T cell exhaustion/dysfunction. LXRβ depletion in chimeric antigen receptor T (CAR-T) cells leads to improved antitumor function against solid tumors. Since T cell cholesterol metabolism and oxysterols are generally linked to other diseases, the new mechanism and cholesterol-normalization strategy might have potential applications elsewhere.

The effect of obesity on chronic diseases in USA: a flexible copula approach

We analyze the effect of obesity on the incidence of hypertension, hyperlipidemia and diabetes in USA using a health production theoretical framework along with a bivariate flexible semi-parametric recursive copula model that account for endogeneity. In this approach, the effects of control variables are flexibly determined using additive predictors that allow for a variety of effects. Our findings suggest that there exist a positive and significant effect of obesity on the prevalence of all chronic diseases examined. In particular, after endogeneity is accounted for, the probability of having hypertension, hyperlipidemia and diabetes for obese individuals are, respectively, 35%, 28% and 11% higher than those under the obesity threshold. These findings suggest that lowering obesity rates could lead to significant reductions in the morbidity and mortality associated with these diseases.

Serum cholesterol and the risk of developing hormonally driven cancers: A narrative review

Although cholesterol has been hypothesized to promote cancer development through several potential pathways, its role in the risk of developing hormonally driven cancer is controversial. This literature review summarizes evidence from the highest quality studies to examine the consistency and strength of the relationship between serum cholesterol parameters and incidence of hormonally driven cancer. Articles were identified using EMBASE. Longitudinal observational studies published between January 2000 and December 2020 were considered for inclusion. The endpoint of interest was incident prostate, ovary, breast, endometrium, and uterine cancers. In total, 2732 reports were identified and screened; 41 studies were included in the review. No associations were found for ovarian cancer. Most endometrial cancer studies were null. The majority (76.9%) of studies reported no association between cholesterol and prostate cancer. Data on breast cancer were conflicting, associations limited, and effect sizes modest. Our results do not provide evidence for a clear association between cholesterol and different types of incident, hormonally driven reproductive cancers. Future studies should investigate the impact of lipid-lowering therapy.

Obesity: a perfect storm for carcinogenesis

Obesity-related cancers account for 40% of the cancer cases observed in the USA and obesity is overtaking smoking as the most widespread modifiable risk factor for carcinogenesis. Here, we use the hallmarks of cancer framework to delineate how obesity might influence the carcinogenic hallmarks in somatic cells. We discuss the effects of obesity on (a) sustaining proliferative signaling; (b) evading growth suppressors; (c) resisting cell death; (d) enabling replicative immortality; (e) inducing angiogenesis; (f) activating invasion and metastasis; (g) reprogramming energy metabolism; and (h) avoiding immune destruction, together with its effects on genome instability and tumour-promoting inflammation. We present the current understanding and controversies in this evolving field, and highlight some areas in need of further cross-disciplinary focus. For instance, the relative importance of the many potentially causative obesity-related factors is unclear for each type of malignancy. Even within a single tumour type, it is currently unknown whether one obesity-related factor consistently plays a predominant role, or if this varies between patients or, even in a single patient with time. Clarifying how the hallmarks are affected by obesity may lead to novel prevention and treatment strategies for the increasingly obese population.

Hypercholesterolemia in Cancer and in Anorexia Nervosa: A Hypothesis for a Crosstalk

The relationship between cholesterol and cancer has been widely demonstrated. Clinical studies have shown changes in blood cholesterol levels in cancer patients. In parallel, basic research studies have shown that cholesterol is involved in the mechanisms of onset and progression of the disease. On the other hand, anorexic patients have high cholesterol levels and a high susceptibility to cancer. In this review, we first present a brief background on the relations among nutrition, eating disorders and cancer. Using several notable examples, we then illustrate the changes in cholesterol in cancer and in anorexia nervosa, providing evidence for their important relationship. Finally, we show a new possible link between cholesterol disorder in cancer and in anorexia nervosa.

Bird's eye view analysis of in situ cholesterol metabolic pathways in breast cancer patients and its clinicopathological significance in their subtypes

Obesity has been known to increase the risks of breast cancer (BC) development and also to be associated with adverse clinical outcome of the patients. Abnormalities of cholesterol metabolism are not only related to obesity but also to biological or clinical behavior of BC patients. However, which metabolites or pathways of cholesterol metabolism could represent the characteristics of BC patients have remained virtually unknown. Therefore, in this study, we attempted to perform bird's eye view or comprehensive analysis of in situ or intra-tumoral cholesterol metabolic pathways using the multimodal approaches in order to elucidate the possible significance of cholesterol metabolites and its metabolic enzymes including CYP27A1, CYP7A1, and CYP46A1. GC-MS study using BC specimens was first performed in 60 BCE patients to evaluate cholesterol metabolism from cholesterol through oxysterols in both BC and normal tissues. Results of those analyses above lead to evaluating immunoreactivity and mRNA expression of CYP27A1, CYP7A1 and CYP46A1 in 213 and 153 BCE cases, respectively. Results of comprehensive GC-MS analysis did reveal that three oxysterols, 27-HC, 7α-HC and 24-HC were all related to malignant phenotypes in BC. 27-HC abundance was significantly associated with higher tumor stage (P = 0.0475) of BC patients. Luminal B type BC patients harboring high CYP27A1, the enzyme responsible for production of 27-HC were significantly associated with worse disease-free survival than those with low CYP27A1 (P = 0.0463). 7α-HC tended to be more abundant in HER2 positive and TNBC subtypes and higher levels of 7α-HC were also significantly associated with higher Ki-67 labeling index (P = 0.0022) and histological grade (P = 0.0286). CYP7A1, the enzyme involved in production of 7α-HC, was significantly more abundant in TNBC than other subtypes (vs Luminal A; P = 0.0321, vs Luminal B; P = 0.0048, vs HER2; P = 0.0103). The levels of 24-HC in BC were lower than normal breast tissues regardless of its subtypes. CYP46A1, the enzyme involved in the production of 24-HC, was detected only in 33 (15.5%) out of 213 BCE cases examined in this study. Results of our bird's eye view analysis of in situ or intra-tumoral cholesterol metabolism in BC patients did firstly reveal BC subtype dependent involvement of its different pathways. Results also indicated the therapeutic possibility of subtype dependent modification of cholesterol metabolizing pathways in BC patients.

Our evolving understanding of how 27-hydroxycholesterol influences cancer

Cholesterol has been implicated in the pathophysiology and progression of several cancers now, although the mechanisms by which it influences cancer biology are just emerging. Two likely contributing mechanisms are the ability for cholesterol to directly regulate signaling molecules within the membrane, and certain metabolites acting as signaling molecules. One such metabolite is the oxysterol 27-hydroxycholesterol (27HC), which is a primary metabolite of cholesterol synthesized by the enzyme Cytochrome P450 27A1 (CYP27A1). Physiologically, 27HC is involved in the regulation of cholesterol homeostasis and contributes to cholesterol efflux through liver X receptor (LXR) and inhibition of de novo cholesterol synthesis through the insulin-induced proteins (INSIGs). 27HC is also a selective modulator of the estrogen receptors. An increasing number of studies have identified its importance in cancer progression of various origins, especially in breast cancer. In this review, we discuss the physiological roles of 27HC targeting these two nuclear receptors and the subsequent contribution to cancer progression. We describe how 27HC promotes tumor growth directly through cancer-intrinsic factors, and indirectly through its immunomodulatory roles which lead to decreased immune surveillance and increased tumor invasion. This review underscores the importance of the cholesterol metabolic pathway in cancer progression and the potential therapeutic utility of targeting this metabolic pathway.

27-Hydroxycholesterol, The Estrogen Receptor Modulator, Alters DNA Methylation in Breast Cancer

27-hydroxycholesterol (27-HC) is the first known endogenous selective estrogen receptor modulator (SERM), and its elevation from normal levels is closely associated with breast cancer. A plethora of evidence suggests that aberrant epigenetic signatures in breast cancer cells can result in differential responses to various chemotherapeutics and often leads to the development of resistant cancer cells. Such aberrant epigenetic changes are mostly dictated by the microenvironment. The local concentration of oxygen and metabolites in the microenvironment of breast cancer are known to influence the development of breast cancer. Hence, we hypothesized that 27-HC, an oxysterol, which has been shown to induce breast cancer progression via estrogen receptor alpha (ERα) and liver X receptor (LXR) and by modulating immune cells, may also induce epigenetic changes. For deciphering the same, we treated the estrogen receptor-positive cells with 27-HC and identified DNA hypermethylation on a subset of genes by performing DNA bisulfite sequencing. The genes that showed significant DNA hypermethylation were phosphatidylserine synthase 2 (PTDSS2), MIR613, indoleamine 2,3-dioxygenase 1 (IDO1), thyroid hormone receptor alpha (THRA), dystrotelin (DTYN), and mesoderm induction early response 1, family member 3 (MIER). Furthermore, we found that 27-HC weakens the DNMT3B association with the ERα in MCF-7 cells. This study reports that 27-HC induces aberrant DNA methylation changes on the promoters of a subset of genes through modulation of ERα and DNMT3B complexes to induce the local DNA methylation changes, which may dictate drug responses and breast cancer development.

Alterations of Gut Microbiome and Metabolite Profiles Associated With Anabatic Lipid Dysmetabolism in Thyroid Cancer

BACKGROUND

Currently, the high morbidity of individuals with thyroid cancer (TC) is an increasing health care burden worldwide. The aim of our study was to investigate the relationship among the gut microbiota community, metabolites, and the development of differentiated thyroid cancer.

METHODS

16S rRNA gene sequencing and an integrated LC-MS-based metabolomics approach were performed to obtain the components and characteristics of fecal microbiota and metabolites from 50 patients with TC and 58 healthy controls (HCs).

RESULTS

The diversity and richness of the gut microbiota in the TC patients were markedly decreased. The composition of the gut microbiota was significantly altered, and the Bacteroides enterotype was the dominant enterotype in TC patients. Additionally, the diagnostic validity of the combined model (three genera and eight metabolites) and the metabolite model (six metabolites) were markedly higher than that of the microbial model (seven genera) for distinguishing TC patients from HCs. LEfSe analysis demonstrated that genera (g_Christensenellaceae_R-7_group, g_Eubacterium_coprostanoligenes_group) and metabolites [27-hydroxycholesterol (27HC), cholesterol] closely related to lipid metabolism were greatly reduced in the TC group. In addition, a clinical serum indicator (total cholesterol) and metabolites (27HC and cholesterol) had the strongest influence on the sample distribution. Furthermore, functional pathways related to steroid biosynthesis and lipid digestion were inhibited in the TC group. In the microbiota-metabolite network, 27HC was significantly related to metabolism-related microorganisms (g_Christensenellaceae_R-7_group).

CONCLUSIONS

Our research explored the characteristics of the gut microecology of patients with TC. The findings of this study will help to discover risk factors that affect the occurrence and development of TC in the intestinal microecology.

Relationship between body mass index and cholesterol levels with histopathological grading of breast cancer

BACKGROUND

Breast cancer, a global health problem with a high mortality rate, has several risk factors, including obesity and increased lipid profile. Postmenopausal obesity is associated with estrogen production from adipose tissue, while abnormal cell growth is triggered by insulin-like growth factor 1 (IGF-1) and insulin. Obesity could be assessed by measuring body mass index (BMI). An increase in lipid profile signifies an increased risk for breast cancer. Histopathological findings in the form of grading and differentiation can indicate how serious the condition is. Breast cancer with good differentiation is always associated with a positive prognosis.

OBJECTIVE

This observational analytic study aims to determine the relationship between BMI and cholesterol levels based on the menopausal status and the histopathological grading findings of breast cancer patients.

METHODS

The observational cross-sectional study analyzed histopathological grading, total cholesterol level, and body mass index. Data were analyzed with Spearman rank correlation statistical test, and the results are significant when the p-value is <0.05.

RESULTS

Analyzing the relationship between cholesterol levels and histopathological gradings indicated a moderate correlation. The results of another correlation test based on menopausal status showed a weak correlation value, while menopause was said to be significant, indicating a moderate correlation. However, results from the analysis of BMI data in the menopausal subject group were associated with histopathological assessment.

CONCLUSIONS

There is a relationship between cholesterol levels and histopathological degrees in the two menopausal status groups. However, no relationship was found between BMI and the histopathological grades of breast cancer.

Resveratrol Alleviates 27-Hydroxycholesterol-Induced Senescence in Nerve Cells and Affects Zebrafish Locomotor Behavior via Activation of SIRT1-Mediated STAT3 Signaling

The oxysterol 27-hydroxycholesterol (27HC) is the first identified endogenous selective estrogen receptor modulator (SERM), which like endogenous estrogen 17β-estradiol (E₂) induces the proliferation of estrogen receptor- (ER-) positive breast cancer cells in vitro. However, 27HC differs from E₂ in that it shows adverse effects in the nervous system. Our previous study confirmed that 27HC could induce neural senescence by activating phosphorylated signal transducer and activator of transcription, which E₂ could not. The purpose of the present study is to investigate whether STAT3 acetylation was involved in 27HC-induced neural senescence. Microglia (BV2 cells) and rat pheochromocytoma cells (PC12 cells) were used in vitro to explore the effect of resveratrol (REV) on 27HC-induced neural senescence. Senescence-associated β-galactosidase (SA-β-Gal) staining was performed using an SA-β-Gal Staining Kit in cells and zebrafish larvae. Zebrafish were used in vivo to assess the effect of 27HC on locomotor behavior and aging. We found that 27HC could induce senescence in neural cells, and REV, which has been employed as a Sirtuin-1 (SIRT1) agonist, could attenuate 27HC-induced senescence by inhibiting STAT3 signaling via SIRT1. Moreover, in the zebrafish model, REV attenuated 27HC-induced locomotor behavior disorder and aging in the spinal cord of zebrafish larvae, which was also associated with the activation of SIRT1-mediated STAT3 signaling. Our findings unveiled a novel mechanism by which REV alleviates 27HC-induced senescence in neural cells and affects zebrafish locomotor behavior by activating SIRT1-mediated STAT3 signaling.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

Exogenous Fatty Acids Modulate ER Lipid Composition and Metabolism in Breast Cancer Cells

(1) Background: Lipid metabolism is a fundamental hallmark of all tumors, especially of breast cancer. Few studies describe the different lipid metabolisms and sensitivities to the microenvironment of breast cancer cell subtypes that influence the proliferation, aggressiveness, and success of therapy. This study describes the impact of lipid microenvironment on endoplasmic reticulum (ER) membrane and metabolic activity in two breast cancer cell lines with Luminal A and triple-negative breast cancer (TNBC) features. (2) Methods: We investigated the peculiar lipid phenotype of a TNBC cell line, MDA-MB-231, and a Luminal A cell line, MCF7, and their different sensitivity to exogenous fatty acids (i.e., palmitic acid (PA) and docosahexaenoic acid (DHA)). Moreover, we verified the impact of exogenous fatty acids on ER lipid composition. (3) Results: The data obtained demonstrate that MDA-MB-231 cells are more sensitive to the lipid microenvironment and that both PA and DHA are able to remodel their ER membranes with consequences on resident enzyme activity. On the contrary, MCF7 cells are less sensitive to PA, whereas they incorporate DHA, although less efficiently than MDA-MB-231 cells. (4) Conclusions: This study sustains the importance of lipid metabolism as an innovative hallmark to discriminate breast cancer subclasses and to develop personalized and innovative pharmacological strategies. The different sensitivities to the lipid environment shown by MCF7 and MDA-MB-231 cells might be related to cell malignancy and chemoresistance onset. In the future, this new approach could lead to a substantial decrease both in deleterious side effects for the patients and in the cost of entire therapeutic treatments coupled with increased therapy efficiency.

Obesity Epidemic-The Underestimated Risk of Endometrial Cancer

Simple Summary

Endometrial cancer is the most frequent gynecologic tumor in developed countries. Obesity is an established risk factor for this disease. This work provides an overview of pathophysiological interactions and pathways in obese women initiating tumorigenesis. Furthermore, the clinical impact of adiposity on the treatment of endometrial cancer is discussed as well therapeutic and preventive options.

Abstract

Endometrial cancer (EC) is the most frequently observed malignant gynecologic disease in developed countries. There is a strong association between the established risk factor obesity and the incidence of EC. Furthermore, the rate of women with a body mass index (BMI) > 30 kg/m² is increasing worldwide, correspondingly leading to a higher prevalence of EC. Understanding the adipose tissue as an endocrine organ, elementary pathophysiological pathways of tumorigenesis have been revealed. This includes the fundamental role of hyperglycemia, insulin resistance, and hyperestrogenemia, as well as interactions with a chronic proinflammatory microenvironment. Therapeutic options potentially include metformin or bariatric surgery. Moreover, changes in individual lifestyle such as weight reduction, physical activity, and an awareness of healthy nutrition are effective in preventing the disease.