Putative role of adipose tissue in growth and metabolism of colon cancer cells

Mitochondrial Ca2+ signaling is a hallmark of specific adipose tissue-cancer crosstalk

Obesity is associated with increased risk and worse prognosis of many tumours including those of the breast and of the esophagus. Adipokines released from the peritumoural adipose tissue promote the metastatic potential of cancer cells, suggesting the existence of a crosstalk between the adipose tissue and the surrounding tumour. Mitochondrial Ca2+ signaling contributes to the progression of carcinoma of different origins. However, whether adipocyte-derived factors modulate mitochondrial Ca2+ signaling in tumours is unknown. Here, we show that conditioned media derived from adipose tissue cultures (ADCM) enriched in precursor cells impinge on mitochondrial Ca2+ homeostasis of target cells. Moreover, in modulating mitochondrial Ca2+ responses, a univocal crosstalk exists between visceral adipose tissue-derived preadipocytes and esophageal cancer cells, and between subcutaneous adipose tissue-derived preadipocytes and triple-negative breast cancer cells. An unbiased metabolomic analysis of ADCM identified creatine and creatinine for their ability to modulate mitochondrial Ca2+ uptake, migration and proliferation of esophageal and breast tumour cells, respectively.

Endothelial dysfunction, platelet hyperactivity, hypertension, and the metabolic syndrome: molecular insights and combating strategies

Metabolic syndrome (MetS) is a multifaceted condition that increases the possibility of developing atherosclerotic cardiovascular disease. MetS includes obesity, hypertension, dyslipidemia, hyperglycemia, endothelial dysfunction, and platelet hyperactivity. There is a concerning rise in the occurrence and frequency of MetS globally. The rising incidence and severity of MetS need a proactive, multipronged strategy for identifying and treating those affected. For many MetS patients, achieving recommended goals for healthy fat intake, blood pressure control, and blood glucose management may require a combination of medicine therapy, lifestyles, nutraceuticals, and others. However, it is essential to note that lifestyle modification should be the first-line therapy for MetS. In addition, MetS requires pharmacological, nutraceutical, or other interventions. This review aimed to bring together the etiology, molecular mechanisms, and dietary strategies to combat hypertension, endothelial dysfunction, and platelet dysfunction in individuals with MetS.

The Expression of Stem Cell Marker LGR5 and Its Coexpression with Β-Catenin in Sporadic Colorectal Carcinoma and Adenoma: A Comparative Immunohistochemical Study

Background: LGR5 is one of the most important stem cell markers for colorectal cancer (CRC), as it potentiates Wnt/Β-catenin signaling. The well-characterized deregulation of Wnt/Β-catenin signaling that occurs during adenoma/carcinoma sequence in CRC renders LGR5 a hopeful therapeutic target. We assessed the immunohistochemical expression of LGR5 and Β-catenin in normal colonic and tumorous lesions with a clinicopathological correlation. Methods: Tissue blocks and clinical data of 50 selected cases were included: 8 from normal mucosa, 12 cases of adenoma, and 30 cases of CRC, where sections were cut and re-examined and the immunohistochemical technique was conducted using anti-LGR5 and anti-Β-catenin to measure the staining density. Results: There was no expression of LGR5 in normal mucosa compared to samples of adenoma and CRC samples. The association analysis showed that CRC specimens were more likely to have strong LGR5 and Β-catenin expressions than the other two groups (p = 0.048 and p < 0.001, respectively). Specimens with high-grade dysplastic adenoma were more likely to express moderate-to-strong expression of LGR5 and Β-catenin (p = 0.013 and p = 0.036, respectively). In contrast, there were no statistically significant associations between LGR5 and Β-catenin expression with grade and stage. Conclusion: These results suggest and support the possible role of LGR5 as a potential marker of cancer stem cells in sporadic colorectal carcinogenesis in addition to a prognostic value for LGR5 and Β-catenin in adenomatous lesions according to immunohistochemical expression density. A potential therapeutic role of LGR5 in CRC is suggested for future studies based on its role in pathogenesis.

The Role of the Microbiome on the Pathogenesis and Treatment of Colorectal Cancer

The gut microbiome has long been known to play a role in various aspects of health modulation, including the pathogenesis of colorectal cancer (CRC). With immunotherapy recently emerging as a successful treatment in microsatellite instability high (MSI-high) CRC, and with a newly demonstrated involvement of the gut microbiome in the modulation of therapeutic responses, there has been an explosion of research into the mechanisms of microbial effects on CRC. Harnessing and reprogramming the microbiome may allow for the expansion of these successes to broader categories of CRC, the prevention of CRC in high-risk patients, and the enhancement of standard treatments. In this review, we pull together both well-documented phenomena and recent discoveries that pertain to the microbiome and CRC. We explore the microbial mechanisms associated with CRC pathogenesis and progression, recent advancements in CRC systemic therapy, potential options for diagnosis and prevention, as well as directions for future research.

Crosstalk of Oxidative Phosphorylation-Related Subtypes, Establishment of a Prognostic Signature and Immune Infiltration Characteristics in Colorectal Adenocarcinoma

Simple Summary

Oxidative phosphorylation (OXPHOS) plays an important role in the progression of colorectal adenocarcinoma (COAD). The aim of our study was to investigate the expression pattern of OXPHOS-related genes (ORGs), and an OXPHOS-related prognostic signature was constructed to classify COAD patients into high-risk and low-risk groups. Then, we analyzed the relationship between risk scores and tumor microenvironment, somatic mutation, and efficacy of immunotherapy and chemotherapy. Additionally, a nomogram was established by combining clinical features and risk scores, and its predictive ability was verified by receiver operating characteristics and calibration curves. Overall, the OXPHOS-related signature can be used as a reliable prognostic predictor of COAD patients.

Abstract

Oxidative phosphorylation (OXPHOS) is an emerging target in cancer therapy. However, the prognostic signature of OXPHOS in colorectal adenocarcinoma (COAD) remains non-existent. We comprehensively investigated the expression pattern of OXPHOS-related genes (ORGs) in COAD from public databases. Based on four ORGs, an OXPHOS-related prognostic signature was established in which COAD patients were assigned different risk scores and classified into two different risk groups. It was observed that the low-risk group had a better prognosis but lower immune activities including immune cells and immune-related function in the tumor microenvironment. Combining with relevant clinical features, a nomogram for clinical application was also established. Receiver operating characteristic (ROC) and calibration curves were constructed to demonstrate the predictive ability of this risk signature. Moreover, a higher risk score was significantly positively correlated with higher tumor mutation burden (TMB) and generally higher gene expression of immune checkpoint, N6-methyladenosine (m6A) RNA methylation regulators and mismatch repair (MMR) related proteins. The results also indicated that the high-risk group was more sensitive to immunotherapy and certain chemotherapy drugs. In conclusion, OXPHOS-related prognostic signature can be utilized to better understand the roles of ORGs and offer new perspectives for clinical prognosis and personalized treatment.

The ambiguous role of obesity in oncology by promoting cancer but boosting antitumor immunotherapy

Obesity is nowadays considered a pandemic which prevalence's has been steadily increasingly in western countries. It is a dynamic, complex, and multifactorial disease which propitiates the development of several metabolic and cardiovascular diseases, as well as cancer. Excessive adipose tissue has been causally related to cancer progression and is a preventable risk factor for overall and cancer-specific survival, associated with poor prognosis in cancer patients. The onset of obesity features a state of chronic low-grade inflammation and secretion of a diversity of adipocyte-derived molecules (adipokines, cytokines, hormones), responsible for altering the metabolic, inflammatory, and immune landscape. The crosstalk between adipocytes and tumor cells fuels the tumor microenvironment with pro-inflammatory factors, promoting tissue injury, mutagenesis, invasion, and metastasis. Although classically established as a risk factor for cancer and treatment toxicity, recent evidence suggests mild obesity is related to better outcomes, with obese cancer patients showing better responses to treatment when compared to lean cancer patients. This phenomenon is termed obesity paradox and has been reported in different types and stages of cancer. The mechanisms underlying this paradoxical relationship between obesity and cancer are still not fully described but point to systemic alterations in metabolic fitness and modulation of the tumor microenvironment by obesity-associated molecules. Obesity impacts the response to cancer treatments, such as chemotherapy and immunotherapy, and has been reported as having a positive association with immune checkpoint therapy. In this review, we discuss obesity's association to inflammation and cancer, also highlighting potential physiological and biological mechanisms underlying this association, hoping to clarify the existence and impact of obesity paradox in cancer development and treatment.

Bioactive food components for colorectal cancer prevention and treatment: A good match

Colorectal cancer (CRC) is the third most frequent cancer worldwide, accounts for about 10% of the total cancer cases, and ranks as the second cause of death by cancer. CRC is more prevalent in developed countries in close causal relation with occidental diets. Due to anatomy, the diet has a strong impact on CRC. High contents in meat are acknowledged risk factors whereas a diet rich in fruits and vegetables is an established CRC protective factor. Fruits and vegetables contain numerous Bioactive Food Components (BFCs), physiologically active food compounds, beneficial on health. Preventive and therapeutic benefits of BFCs in cancer have increasingly been reported over the past 20 years. BFCs show both chemopreventive and anti-tumor properties in CRC but more interestingly, abundant research describes BFCs as enhancers of conventional cancer treatments. Despite these promising results, their clinical transferability is slowed down by bioavailability interrogations and their poorly understood hormetic effect. In this review, we would like to reposition BFCs as well-fitted for applications in CRC. We provide a synthetic overview of trustworthy BFC applications in CRC, with a special highlight on combinatory approaches and conventional cancer treatment potentiation strategies.

Novel evidence of obesity paradox in esophageal adenocarcinoma: perspective on genes that uncouple adiposity from dismal outcomes

Background: Obesity is a strong risk factor for esophageal adenocarcinoma (EAC). Nevertheless, not all the patients with EAC are obesity, and a substantial proportion of obesity patients don't suffer from poor prognoses. The mechanisms behind the “obesity paradox” that uncouple obesity from dismal outcomes in EAC are unclear. This study aimed to explore the “obesity-guarding” genes (OGG) profiles and their prognostic values in patients with EAC.

Methods: Gene expression data and clinical information of patients with EAC were downloaded from The Cancer Genome Atlas (TCGA) database. Enrichment analysis was used to explore the OGG functions and pathways. Cox regression analysis and nomogram model were performed to investigate the OGG prognostic values for overall survival (OS). In addition, relations between OGG and immune cells were assessed by the “CIBERSORT” algorithm and the Tumor IMmune Estimation Resource (TIMER) tool. Finally, the results were experimentally validated in real-world study.

Results: A total of 69 OGG were retrieved, and 17 significantly differentially expressed genes (SDEG) were identified between normal and EAC tissues. Enrichment analysis showed the OGG were enriched in the mitochondrion-related and various receptor pathways. Univariate Cox regression results showed that the MCM6, ATXN2 and CSK were significantly associated with OS (P=0.036, 0.039, 0.046, respectively). Multivariate Cox regression analysis showed MCM6 and CSK were independent prognostic genes for OS (P=0.025, 0.041, respectively). Nomogram demonstrated that the OGG had good predictive abilities for the 1-, 2-, and 3-year OS. Immunity analysis demonstrated that OGG were significantly associated with immune cells (P <0.05). In addition, clinical correlation analysis revealed that the OGG had significant relations with clinical parameters (P <0.05). The experiment results confirmed that the SDEG were significantly different between normal and EAC tissues (P <0.05).

Conclusions: We identified the OGG expression profiles that may uncouple obesity from poor survival in patients with EAC. They have prognostic values in predicting patients' OS, and may be exploited for prognostic biomarkers.

Impact of a ketogenic diet intervention during radiotherapy on body composition: IV. Final results of the KETOCOMP study for rectal cancer patients

BACKGROUND & AIMS

Obesity and low muscle mass are associated with worse outcomes of colorectal cancer patients. We conducted a controlled trial to study the impact of a ketogenic diet (KD) based on natural foods versus an unspecified standard diet (SD) on body composition in rectal cancer patients undergoing radiotherapy.

METHODS

Patients with non-metastasized rectal cancer were allocated to either the KD (N = 24) or the SD (N = 25) group during radiotherapy. Body composition was measured weekly by bioimpedance analysis and analyzed using linear mixed effects models. Pathologic response in patients undergoing neoadjuvant treatment was evaluated at the time of surgery.

RESULTS

A total of 18 KD and 23 SD patients completed the study and were eligible for analysis. The SD group experienced no noteworthy changes in any body composition parameter. In contrast, patients in the KD group lost significant amounts of body weight and fat mass, averaging 0.5 and 0.65 kg/week (p < 0.0001). There was a rapid loss of intracellular water consistent with initial intramuscular glycogen and water depletion, but skeletal muscle tissue was conserved. Pathological tumor responses were somewhat greater in the KD group, with a larger mean Dworak regression grade (p = 0.072) and larger percentage of near-complete (yT0N0 or yT1N1) responses (43 versus 15%, p = 0.116) that almost reached statistical significance in intention-to-treat analysis (50% versus 14%, p = 0.018).

CONCLUSIONS

In rectal cancer patients undergoing curative radiotherapy, a KD significantly reduced body weight and fat mass while preserving skeletal muscle mass. We could demonstrate a trend for KDs contributing synergistically to pathological tumor response, a finding in line with preclinical data that warrants future confirmation in larger studies.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02516501, registered on August 06, 2015.

Obesity-Associated Inflammation: Does Curcumin Exert a Beneficial Role?

Curcumin is a lipophilic polyphenol, isolated from the plant turmeric of Curcuma longa. Curcuma longa has always been used in traditional medicine in Asian countries because it is believed to have numerous health benefits. Nowadays it is widely used as spice component and in emerging nutraceutical food worldwide. Numerous studies have shown that curcumin possesses, among others, potential anti-inflammatory properties. Obesity represents a main risk factor for several chronic diseases, including type 2 diabetes, cardiovascular disease, and some types of cancer. The establishment of a low-grade chronic inflammation, both systemically and locally in adipose tissue, occurring in obesity most likely represents a main factor in the pathogenesis of chronic diseases. The molecular mechanisms responsible for the onset of the obesity-associated inflammation are different from those involved in the classic inflammatory response caused by infections and involves different signaling pathways. The inflammatory process in obese people is triggered by an inadequate intake of nutrients that produces quantitative and qualitative alterations of adipose tissue lipid content, as well as of various molecules that act as endogenous ligands to activate immune cells. In particular, dysfunctional adipocytes secrete inflammatory cytokines and chemokines, the adipocytokines, able to recruit immune cells into adipose tissue, amplifying the inflammatory response also at systemic level. This review summarizes the most recent studies focused at elucidating the molecular targets of curcumin activity responsible for its anti-inflammatory properties in obesity-associated inflammation and related pathologies.

Natural Polyphenols as Targeted Modulators in Colon Cancer: Molecular Mechanisms and Applications

Colon cancer commonly develops from long-term chronic inflammation in the intestine and seriously threatens human health. Natural polyphenols have been valued as a crucial regulator of nutrient metabolism and metabolic diseases, owing to their anti-inflammatory and antioxidant functions and the ability to maintain a balance between gut microbes and their hosts. Notably, experimental and clinical evidence has shown that natural polyphenols could act as a targeted modulator to play a key role in the prevention or treatment of colon cancer. Thus, in this review, we summarized recent advances in the possible regulatory mechanism and the potential application of natural polyphenols in colon cancer, which might be regarded as a novel platform for the colon cancer management.

The Role of Tumor Microenvironment Cells in Colorectal Cancer (CRC) Cachexia

Cancer cachexia (CC) is a multifactorial syndrome in patients with advanced cancer characterized by weight loss via skeletal-muscle and adipose-tissue atrophy, catabolic activity, and systemic inflammation. CC is correlated with functional impairment, reduced therapeutic responsiveness, and poor prognosis, and is a major cause of death in cancer patients. In colorectal cancer (CRC), cachexia affects around 50–61% of patients, but remains overlooked, understudied, and uncured. The mechanisms driving CC are not fully understood but are related, at least in part, to the local and systemic immune response to the tumor. Accumulating evidence demonstrates a significant role of tumor microenvironment (TME) cells (e.g., macrophages, neutrophils, and fibroblasts) in both cancer progression and tumor-induced cachexia, through the production of multiple procachectic factors. The most important role in CRC-associated cachexia is played by pro-inflammatory cytokines, including the tumor necrosis factor α (TNFα), originally known as cachectin, Interleukin (IL)-1, IL-6, and certain chemokines (e.g., IL-8). Heterogeneous CRC cells themselves also produce numerous cytokines (including chemokines), as well as novel factors called “cachexokines”. The tumor microenvironment (TME) contributes to systemic inflammation and increased oxidative stress and fibrosis. This review summarizes the current knowledge on the role of TME cellular components in CRC-associated cachexia, as well as discusses the potential role of selected mediators secreted by colorectal cancer cells in cooperation with tumor-associated immune and non-immune cells of tumor microenvironment in inducing or potentiating cancer cachexia. This knowledge serves to aid the understanding of the mechanisms of this process, as well as prevent its consequences.

Pathological and immunohistochemical study of colon cancer. Evaluation of markers for colon cancer stem cells

Colorectal cancer is a major public health problem worldwide with increasing morbidity and mortality. Numerous exogenous and endogenous factors are involved in colorectal carcinogenesis: age, sex, diet, smoking, alcohol consumption, exposure to harmful environmental factors, intestinal microbiota, bacterial and viral infections, the ability of the host immune system to respond, genetic factors, etc. The present study analyzed histopathologically and immunohistochemically a number of 36 cases of colorectal adenocarcinomas. The existence of an accentuated cell pleomorphism was noted, which corresponds to different clones of tumor cells, in the same tumor coexisting aspects of tubular adenocarcinoma, mucinous areas and even signet-ring cell. The tumor stroma was mainly of the desmoplastic type, but also of the lax type, more or less infiltrated with inflammatory cells. Evaluation of immunomarkers for cancer stem cells (CSCs) showed that none of the markers used alone [cluster of differentiation (CD)133, CD44, aldehyde dehydrogenase 1 family member A1 (ALDH1A1), CD24, CD26] show CSCs.

Colorectal Cancer in County Durham-England a Clinical and Statistical Study

Colorectal cancer is one of the most frequently occurring malignancies which associates increasing mortality and morbidity rates. According to data provided by the World Health Organization, colorectal cancer deaths account for approximately 13% of all cancer fatalities. The carcinogenesis of this type of malignancy is a very complex process characterized by various molecular changes which in turn are influenced by factors likes sex, diet, intestinal microbiota, exposure to environmental factors, hosts' immune response and also genetic factors. Our study looked at a total number of 1024 patients, which were all diagnosed with colorectal cancer in a hospital in the north of England, a country that is known for both a high prevalence of this type of cancer but also its robust screening programmers. In our analyses, we concluded that this type of malignancies affected mostly males, aged between 60 and 80. The most commonly affected regions were the rectum, the sigmoid colon and also the cecum. The majority of colorectal cancers (51%) were diagnosed by GPs (general practitioners) or other medical specialties; 43.55% of all cases presented as surgical emergencies and 5.47% were diagnosed through national screening programs. Majority of tumors were diagnosed in late stages, mainly T3 and T4 whilst in was observed that rectal cancers were mainly diagnosed in T2 and T3 stages.

Tumor cells hijack enteric glia to activate colon cancer stem cells and stimulate tumorigenesis

BACKGROUND

Colon cancer stem cells (CSCs), considered responsible for tumor initiation and cancer relapse, are constantly exposed to regulatory cues emanating from neighboring cells present in the tumor microenvironment. Among these cells are enteric glial cells (EGCs) that are potent regulators of the epithelium functions in a healthy intestine. However, whether EGCs impact CSC-driven tumorigenesis remains unknown.

METHODS

Impact of human EGC primary cultures or a non-transformed EGC line on CSCs isolated from human primary colon adenocarcinomas or colon cancer cell lines with different p53, MMR system and stemness status was determined using murine xenograft models and 3D co-culture systems. Supernatants of patient-matched human primary colon adenocarcinomas and non-adjacent healthy mucosa were used to mimic tumor versus healthy mucosa secretomes and compare their effects on EGCs.

FINDINGS

Our data show that EGCs stimulate CSC expansion and ability to give rise to tumors via paracrine signaling. Importantly, only EGCs that were pre-activated by tumor epithelial cell-derived soluble factors increased CSC tumorigenicity. Pharmacological inhibition of PGE2 biosynthesis in EGCs or IL-1 knockdown in tumor epithelial cells prevented EGC acquisition of a pro-tumorigenic phenotype. Inhibition of PGE2 receptor EP4 and EGFR in CSCs inhibited the effects of tumor-activated EGCs.

INTERPRETATION

Altogether, our results show that EGCs, once activated by the tumor, acquire a pro-tumorigenic phenotype and stimulate CSC-driven tumorigenesis via a PGE2/EP4/EGFR-dependent pathway.

FUNDING

This work was supported by grants from the French National Cancer Institute, La Ligue contre le Cancer, the 'Région des Pays de la Loire' and the UNC Lineberger Comprehensive Cancer Center.

Adipocytes Isolated from Visceral and Subcutaneous Depots of Donors Differing in BMI Crosstalk with Colon Cancer Cells and Modulate their Invasive Phenotype

PURPOSE: Mechanisms related the crosstalk between adipocytes and colon cancer cells are still not clear. We hypothesize that molecules and adipocytokines generated from the adipose tissue of obese individuals accentuate the effect on the metabolic reprogramming in colon cancer cells, i.e. induce disarray in energy metabolism networks of the targeted affected colonic epithelial cells, prompting their malignant phenotype. METHODS: To explore the mechanistic behind this crosstalk we conducted a co-culture model system using human colon cancer cells having different malignant abilities and adipocytes from different depots and subjects. RESULTS: The results demonstrate that co-culturing aggressive colon cancer cells such as HM-7 cells, with Visceral or Subcutaneous adipocytes (VA or SA respectively) from lean/obese subjects significantly up-regulate the secretion of the adipokines IL-8, MCP1, and IL-6 from the adipocytes. Surprisingly, the response of co-culturing HM-7 cells with obese SA was substantially more significant. In addition, these effects were significantly more pronounced when using HM-7 cells as compared to the less malignant HCT116 colon cancer cells. Moreover, the results showed that HM-7 cells, co-cultured with VA or SA from obese subjects, expressed higher levels of fatty acid binding protein 4; thus, the conditioned media obtained from the wells contained HM-7 cells and adipocytes from obese subjects was significantly more efficient in promoting invasion of HM-7 cells. CONCLUSIONS: We conclude that interaction between adipocytes and colon cancer cells, especially the highly malignant cells, results in metabolic alterations in colon cancer cells and in highly hypertrophy phenotype which characterized by increasing adipokines secretion from the adipocytes.

Targeting of lipid metabolism with a metabolic inhibitor cocktail eradicates peritoneal metastases in ovarian cancer cells

Ovarian cancer is an intra-abdominal tumor in which the presence of ascites facilitates metastatic dissemination, and associated with poor prognosis. However, the significance of metabolic alterations in ovarian cancer cells in the ascites microenvironment remains unclear. Here we show ovarian cancer cells exhibited increased aggressiveness in ascites microenvironment via reprogramming of lipid metabolism. High lipid metabolic activities are found in ovarian cancer cells when cultured in the ascites microenvironment, indicating a metabolic shift from aerobic glycolysis to β-oxidation and lipogenesis. The reduced AMP-activated protein kinase (AMPK) activity due to the feedback effect of high energy production led to the activation of its downstream signaling, which in turn, enhanced the cancer growth. The combined treatment of low toxic AMPK activators, the transforming growth factor beta-activated kinase 1 (TAK1) and fatty acid synthase (FASN) inhibitors synergistically impair oncogenic augmentation of ovarian cancer. Collectively, targeting lipid metabolism signaling axis impede ovarian cancer peritoneal metastases.

LEPR polymorphisms and haplotypes in Mexican patients with colorectal cancer

INTRODUCTION

Obesity and colorectal cancer could be linked by adipocytokines, which are proteins associated with cell proliferation. High levels of the adipocytokine leptin promote the development of colorectal cancer through its receptor.

OBJECTIVE

To determine the association between c.326A>G and c.668A>G LEPR gene polymorphisms and colorectal cancer.

MATERIALS AND METHODS

DNA was extracted from the peripheral blood of 147 patients with sporadic colorectal cancer and 134 healthy people. Genotypes were obtained by PCRRFLP and the association was determined by the odds ratio (OR) test using the SPSS™, version 10.0, program. Haplotype frequencies and linkage disequilibrium were estimated by the Arlequin, version 3.5, software.

RESULTS

Both polymorphisms were in Hardy-Weinberg equilibrium. Only the c.326A>G heterozygous genotype revealed an increased risk for colorectal cancer development (OR=1.81, 95% CI=1.04-3.16, p=0.04). The AG haplotype showed a significant association with colorectal cancer (OR=0.58, 95% CI=0.35-0.96, p<0.03). Linkage disequilibrium between the variants was only evident for the patients group (r2=0.36).

CONCLUSION

Our results suggest that AG individuals heterozygous for the c.326A>G LEPR variant have a higher risk of colorectal cancer development whereas the AG haplotype (c.326A/c.668G) has a protective effect in the Mexican population.

A ketogenic diet exerts beneficial effects on body composition of cancer patients during radiotherapy: An interim analysis of the KETOCOMP study

Background and aim

Ketogenic diets (KDs) have gained interest as a complementary treatment for cancer patients. Here we present first results of our ongoing KETOCOMP study (NCT02516501) concerning body composition changes among rectal, breast and head & neck cancer (HNC) patients who consumed a KD during curative radiotherapy (RT).

Experimental procedure

Sixty-one patients eating a non-ketogenic diet were compared to 20 patients on a KD supplemented with 10 g essential amino acids on RT days. Body composition was measured prior to and weekly during RT using 8-electrode bioimpedance analysis. Longitudinal body composition data were analyzed using linear mixed effects models.

Results and conclusion

Patients on the KD exhibited nutritional ketosis, defined as serum β-hydroxybutyrate levels ≥0.5 mmol/l, in a median of 69.0% of blood measurements (range 0–100%) performed in our clinic. In rectal and breast cancer patients, KD was significantly associated with a loss of 0.5 and 0.4 kg fat mass per week (p = 0.00089 and 8.49 × 10⁻⁵, respectively), with no significant changes in fat free and skeletal muscle mass. In HNC patients, concurrent chemotherapy was the strongest predictor of body weight, fat free and skeletal muscle mass loss during RT, while consuming a KD was significantly associated with a gain in these measures. These preliminary results confirm prior reports indicating that KDs are safe to consume during standard-of-care therapy. They also provide an important first indication that KDs with ample amino acid intake could improve body composition during RT in curative cancer patients.

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Consumption of a ketogenic diet (KD) during radio(chemo-)therapy is feasible.

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In rectal and breast cancer patients, the KD significantly reduced fat mass.

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Fat-free mass and skeletal muscle mass were preserved by the KD.

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In head and neck cancer patients a KD influenced body composition opposite to chemotherapy.

[Role of adipose tissue in the development and progression of colorectal cancer]

The paper gives the current data available in the literature on the relationship and pathogenetic mechanisms of influence of adipose tissue on colorectal carcinogenesis. It considers the aspects of changes in adipose tissue and microenvironment of the tumor itself, including those under the influence of biologically active substances secreted by adipocytes; differences in subcutaneous and visceral fat and their importance in the development and progression of colorectal cancer (CRC), as well as the role of adipose tissue-derived stem cells. Understanding these mechanisms for adipose tissue influence on CRC will assist not only in preventing this disease, but also in searching for new therapeutic targets.

Obesity impacts the regulation of miR-10b and its targets in primary breast tumors

BACKGROUND

Obesity increases breast cancer (BC) risk in post-menopausal women by mostly unknown molecular mechanisms which may partly be regulated by microRNAs (miRNAs).

METHODS

We isolated RNA from paired benign and malignant biopsies from 83 BC patients and determined miRNA profiles in samples from 12 women at the extremes of the BMI distribution by RNA-seq. Candidates were validated in all samples. Associations between miR-10b expression and validated target transcript levels, and effects of targeted manipulation of miR-10b levels in a primary BC cell line on proliferation and invasion potential, were explored.

RESULTS

Of the 148 miRNAs robustly expressed in breast tissues, the levels of miR-21, miR-10b, miR-451a, miR-30c, and miR-378d were significantly associated with presence of cancer. Of these, miR-10b showed a stronger down-regulation in the tumors of the obese subjects, as opposed to the lean. In ductal but not lobular tumors, significant inverse correlations were observed between the tumor levels of miR-10b and miR-30c and the mRNA levels of cancer-relevant target genes SRSF1, PIEZO1, MAPRE1, CDKN2A, TP-53 and TRA2B, as well as tumor grade. Suppression of miR-10b levels in BT-549 primary BC-derived cells increased cell proliferation and invasive capacity, while exogenous miR-10b mimic decreased invasion. Manipulation of miR-10b levels also inversely affected the mRNA levels of miR-10b targets BCL2L11, PIEZO1 and NCOR2.

CONCLUSIONS

Our findings suggest that miR-10b may be a mediator between obesity and cancer in post-menopausal women, regulating several known cancer-relevant genes. MiR-10b expression may have diagnostic and therapeutic implications for the incidence and prognosis of BC in obese women.

Tributyrin in Inflammation: Does White Adipose Tissue Affect Colorectal Cancer?

Colorectal cancer affects the large intestine, leading to loss of white adipose tissue (WAT) and alterations in adipokine secretion. Lower incidence of colorectal cancer is associated with increased fibre intake. Fructooligosaccharides (FOS) are fibres that increase production of butyrate by the intestinal microbiota. Tributyrin, a prodrug of butyric acid, exerts beneficial anti-inflammatory effects on colorectal cancer. Our aim was to characterise the effects of diets rich in FOS and tributyrin within the context of a colon carcinogenesis model, and characterise possible support of tumorigenesis by WAT. C57/BL6 male mice were divided into four groups: a control group (CT) fed with chow diet and three colon carcinogenesis-induced groups fed either with chow diet (CA), tributyrin-supplemented diet (BUT), or with FOS-supplemented diet. Colon carcinogenesis decreased adipose mass in subcutaneous, epididymal, and retroperitoneal tissues, while also reducing serum glucose and leptin concentrations. However, it did not alter the concentrations of adiponectin, interleukin (IL)-6, IL-10, and tumour necrosis factor alpha (TNF)-α in WAT. Additionally, the supplements did not revert the colon cancer affected parameters. The BUT group exhibited even higher glucose tolerance and levels of IL-6, VEGF, and TNF-α in WAT. To conclude our study, FOS and butyrate supplements were not beneficial. In addition, butyrate worsened adipose tissue inflammation.

NLRP3 Inflammasome: A Possible Link Between Obesity-Associated Low-Grade Chronic Inflammation and Colorectal Cancer Development

Emerging evidence reveals that adipose tissue-associated inflammation is a main mechanism whereby obesity promotes colorectal cancer risk and progression. Increased inflammasome activity in adipose tissue has been proposed as an important mediator of obesity-induced inflammation and insulin resistance development. Chronic inflammation in tumor microenvironments has a great impact on tumor development and immunity, representing a key factor in the response to therapy. In this context, the inflammasomes, main components of the innate immune system, play an important role in cancer development showing tumor promoting or tumor suppressive actions depending on the type of tumor, the specific inflammasome involved, and the downstream effector molecules. The inflammasomes are large multiprotein complexes with the capacity to regulate the activation of caspase-1. In turn, caspase-1 enhances the proteolytic cleavage and the secretion of the inflammatory cytokines interleukin (IL)-1β and IL-18, leading to infiltration of more immune cells and resulting in the generation and maintenance of an inflammatory microenvironment surrounding cancer cells. The inflammasomes also regulate pyroptosis, a rapid and inflammation-associated form of cell death. Recent studies indicate that the inflammasomes can be activated by fatty acids and high glucose levels linking metabolic danger signals to the activation of inflammation and cancer development. These data suggest that activation of the inflammasomes may represent a crucial step in the obesity-associated cancer development. This review will also focus on the potential of inflammasome-activated pathways to develop new therapeutic strategies for the prevention and treatment of obesity-associated colorectal cancer development.

Metabolic syndrome and cancer risk: The role of xanthine oxidoreductase

Obesity and related pathologies such as diabetes and metabolic syndrome are associated with chronic inflammation and cancer. The serum level of xanthine oxidoreductase (XOR) is correlated to obesity-associated metabolic disorders. XOR can play a role in the pathogenesis of both metabolic syndrome and cancer through the inflammatory response and the oxidative stress elicited by the products of its activity. The reactive oxygen and nitrogen species and the uric acid derived from XOR concur to the development of hypertension, dyslipidemia and insulin resistance and participate in both cell transformation and proliferation, as well as in the progression and metastasis process. Despite the availability of different drugs to inhibit in vivo XOR activity, the complexity of XOR inhibition effects should be carefully considered before clinical application, save in the case of symptomatic hyperuricemia.

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Metabolic syndrome (MS) increases the risk of cancer development.

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Xanthine oxidoreductase (XOR) plays a role in both MS and cancer.

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Uric acid, ROS and RNS produced by XOR cause inflammation and oxidative stress.

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Inflammation and oxidative stress contribute to the pathogenesis of MS and cancer.

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XOR activity can be pharmacologically controlled.

Colorectal Cancer and Mitochondrial Dysfunctions of the Adjunct Adipose Tissues: A Case Study

Excess body weight has been causally linked to an increased risk of different cancer types, including colorectal cancer (CRC) but the mechanisms underlying this association are practically unknown. We investigate redox state-superoxide (SO) generation rate, activity of complex I in electron transport chain (ETC) of mitochondria and of dinitrosyl iron complexes by electron paramagnetic resonance; activity of matrix metalloproteinase (gelatinase) MMP-2 and MMP-9 by gel zymography of adipose tissues (AT) from 46 patients (64.0 ± 1.6 y.o.) with CRC (II-III stages, pT2-3N0-2M0) in the AT adjacent to tumor (ATAT) and at a distance of 3 cm from the tumor (ATD) to follow the connection of the AT redox state with some of the tumor microenvironment indicators. We have incubated the AT species with the tumor necrosis factor α (TNF-α) to follow its influence on the measured values. As a control, normal AT (NAT) obtained during the liposuction is used. Tumor-induced changes in mitochondrial ETC of ATAT, particularly for Complex I, lead to the enhanced SO generation and consequent oxidative modifications of DNA in ATAT (up to 6.1 times higher than that in NAT and 3.7 times higher than that in ATD, p < 0.05). Gelatinase activity in ATAT is significantly higher than in ATD. A considerable effect of TNF-α on ATAT and ATD (but not on NAT, i.e., only on the tissues where the reprogramming of metabolism has already occurred under the influence of tumor) manifested in increase of cellular hypoxia, gelatinase activity, and SO generation rate is observed. The results can be used for better understanding the mechanism(s) of metabolic symbiosis of tumor and AT as well as serving as a basis for new therapeutic approaches.

The adipose organ and multiple myeloma: Impact of adipokines on tumor growth and potential sites for therapeutic intervention

In addition to its capacity to store lipids the adipose tissue is now identified as a real organ with both endocrine and metabolic roles. Preclinical results indicate that modifying adipose tissue and bone marrow adipose tissue (BMAT) could be a successful multiple myeloma (MM) therapy. BMAT interrelates with bone marrow cells and other immune cells, and may influence MM disease progression. The BM adipocytes may have a role in MM progression, bone homing, chemoresistance, and relapse, due to local endocrine, paracrine, or metabolic factors. BM adipocytes isolated from MM subjects have been shown to increase myeloma growth in vitro and may preserve cells from chemotherapy-induced apoptosis. By producing free fatty acids and emitting signaling molecules such as growth factors and adipokines, BM adipocytes are both an energy font and an endocrine signaling factory. This review should suggest future research approaches toward developing novel treatments to target MM by targeting BMAT and its products.

PGC-1α as a Biomarker of Physical Activity-Protective Effect on Colorectal Cancer

Colorectal cancer is a significant public health concern. As a multistage and multifactorial disease, environmental and genetic factors interact at each stage of the process, and an individual's lifestyle also plays a relevant role. We set out to review the scientific evidence to study the need to investigate the role of the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) gene as a biomarker of the physical activity's (PA) effect on colorectal cancer. PA is a protective factor against colorectal cancer and usually increases the expression of PGC-1α This gene has pleiotropic roles and is the main regulator of mitochondrial functions. The development of colorectal cancer has been associated with mitochondrial dysfunction; in addition, alterations in this organelle are associated with colorectal cancer risk factors, such as obesity, decreased muscle mass, and the aging process. These are affected by PA acting, among other aspects, on insulin sensitivity and oxygen reactive species/redox balance. Therefore, this gene demands special attention in the understanding of its operation in the consensual protective effect of PA in colorectal cancer. A significant amount of indirect evidence points to PGC-1α as a potential biomarker in the PA-protective effect on colorectal cancer. The article focuses on the possible involvement of PGC-1α in the protective role that physical activity has on colorectal cancer. This is an important topic both in relation to advances in prevention of the development of this widespread disease and in its therapeutic treatment. We hope to generate an initial hypothesis for future studies associated with physical activity-related mechanisms that may be involved in the development or prevention of colorectal cancer. PGC-1α is highlighted because it is the main regulator of mitochondrial functions. This organelle, on one hand, is positively stimulated by physical activity; on the other hand, its dysfunction or reduction increases the probability of developing colorectal cancer. Therefore, we consider the compilation of existing information about the possible ways to understand the mechanisms of this gene to be highly relevant. This study is based on evidence of PGC-1α and physical activity, on PGC-1α and colorectal cancer, on colorectal cancer and physical activity/inactivity, and the absence of studies that have sought to relate all of these variables. Cancer Prev Res; 11(9); 523-34. ©2018 AACR.

Differential Tissue Fatty Acids Profiling between Colorectal Cancer Patients with and without Synchronous Metastasis

The early detection of colorectal cancer and determination of its metastatic potential are important factors to set up more efficacious therapeutic strategies. In the present study, we hypothesize that fatty acids analysis in colorectal cancer patients can discriminate between metastatic and non-metastatic patients. Fifty-one consecutive patients with histologically proven colorectal cancer were enrolled in the study and the presence of synchronous metastasis was detected in 25 of these 51 patients. Fatty acid profile analysis in red blood cell membranes was not able to discriminate the metastatic colorectal cancer patients from those without metastasis. However, significant differences in the tumor tissue fatty acid profile were found in metastatic cancer patients when compared to patients without metastasis. Metastatic patients showed significantly lower percentages of Eicosapentaenoic acid (EPA) and higher levels of γ-linolenic acid (GLA), a n-3- and n-6-Polyunsaturated fatty acid (PUFA), respectively. Our findings, suggesting that membrane lipid rearrangement could influence the cellular function and make the cell more prone to metastasis, offer the opportunity to develop nutritional strategies that may be helpful in the prevention and treatment of colorectal cancer.

Bone marrow adipocytes promote the Warburg phenotype in metastatic prostate tumors via HIF-1α activation

Metabolic adaptation is increasingly recognized as a key factor in tumor progression, yet its involvement in metastatic bone disease is not understood. Bone is as an adipocyte-rich organ, and a major site of metastasis from prostate cancer. Bone marrow adipocytes are metabolically active cells capable of shaping tumor metabolism via lipolysis and lipid transfer. In this study, using in vitro and in vivo models of marrow adiposity, we demonstrate that marrow fat cells promote Warburg phenotype in metastatic prostate cancer cells. We show increased expression of glycolytic enzymes, increased lactate production, and decreased mitochondrial oxidative phosphorylation in tumor cells exposed to adipocytes that require paracrine signaling between the two cell types. We also reveal that prostate cancer cells are capable of inducing adipocyte lipolysis as a postulated mechanism of sustenance. We provide evidence that adipocytes drive metabolic reprogramming of tumor cells via oxygen-independent mechanism of HIF-1α activation that can be reversed by HIF-1α downregulation. Importantly, we also demonstrate that the observed metabolic signature in tumor cells exposed to adipocytes mimics the expression patterns seen in patients with metastatic disease. Together, our data provide evidence for a functional relationship between marrow adipocytes and tumor cells in bone that has likely implications for tumor growth and survival within the metastatic niche.

The mechanisms linking obesity to colon cancer: An overview

Obesity, characterised as a chronic low-grade inflammation is a crucial risk factor for colon cancer. The expansion of the adipose tissue is related to elevated triglyceride and low-density lipoprotein (LDL) levels and hyperinsulinemia, which all are presumed mediators of the tumour development. Obesity is also believed to support carcinogenesis by activating the insulin/IGF-1 pathway. Moreover, obesity increases the level of proinflammatory cytokines (e.g. TNF-α, IL-1, and IL-6) and has a significant impact on selected adipokines. This paper briefly outlines the latest evidence of the linkage between the obesity and colon cancer and discusses its possible implication for the improvement of anticancer prevention and treatment strategies connected with nutrition.

Ginsenoside Rb1 inhibits free fatty acids‑induced oxidative stress and inflammation in 3T3‑L1 adipocytes

Free fatty acids (FFAs) increase in visceral fat and are inferred to be one of the underlying inducers of adipose tissue inflammation. In our previous study, it was demonstrated that ginsenoside Rb1 stimulates endothelial nitric oxide synthase (eNOS) and Sirtuin 1 to protect against endothelial cell senescence. In the present study, 3T3‑L1 adipocytes were exposed to 0.5 mM FFAs with or without Rb1 (10‑40 µM). Monocyte chemotactic protein‑1 (MCP‑1) and interleukin‑6 (IL‑6) secretion was measured using ELISA. Tumor necrosis factor‑α (TNF‑α) expression and nuclear factor‑κB (NF‑κB) p65 phosphorylation were detected using western blot analysis. Oxidative stress was determined via measuring intracellular reactive oxygen species (ROS) and nitric oxide (NO) production. The results demonstrated that MCP‑1 and IL‑6 secretion, as well as TNF‑α expression, were significantly increased following FFA treatment, which was attenuated by Rb1 in a dose‑dependent manner. Furthermore, Rb1 attenuated FFA‑induced NF‑κB phosphorylation, suggesting that the inhibitory effect of Rb1 on inflammatory cytokines was partially mediated through blockade of NF‑κB phosphorylation. Further experiments demonstrated that Rb1 ameliorated FFA‑induced ROS generation and NO reduction through upregulation of superoxide dismutase 2 and eNOS expression. Taken together, these results demonstrate proinflammatory and pro‑oxidant effects of FFA on 3T3‑L1 adipocytes, which are effectively ameliorated by Rb1. Suppression of inflammatory responses and oxidative stress may be a novel mechanism for attenuating the effect of Rb1 on adipocyte dysfunction.

Consumption of Lake Ontario sport fish and the incidence of colorectal cancer in the New York State Angler Cohort Study (NYSACS)

Fish consumption is hypothesized to reduce the risk of colorectal cancer. Nonetheless, consuming sport fish from the Great Lakes increases exposure to certain persistent organic pollutants, namely polychlorinated biphenyls (PCBs) and organochlorine insecticides, which may increase the risk of cancer. Evidence that exposure to persistent organic pollutants is associated with colorectal cancer is sparse. We examined colorectal cancer incidence in the New York State Angler Cohort Study (NYSACS), a prospective cohort of 17,110 anglers and spouses age 18-40 years at enrollment. In 1991, participants completed a mailed self-administered questionnaire that ascertained the number of years that fish from Lake Ontario were consumed, as well as potential confounders. Forty-one histologically confirmed first primary incident colorectal cancers diagnosed as of December 31, 2008 were identified via the New York State Cancer Registry. Vital status was ascertained by linkage with the Social Security Administration Death File. Rate ratios (RR) and 95% confidence intervals (CI) were calculated with Poisson regression, adjusting for age, pack-years of smoking, and sex. Compared with never consumers, colorectal cancer incidence was statistically non-significantly lower among consumers of Lake Ontario sport fish (RR=0.66; 95% CI: 0.35; 1.24). Incidence of colon cancer was lower among Lake Ontario sport fish consumers (RR=0.45, 95%CI: 0.20; 1.00). We did not observe any evidence of effect measure modification by sex or age. Although consumption of Lake Ontario sport fish may have an inverse association with colorectal cancer risk, inferences are complicated by a small number of cases and a lack of information regarding potential confounders including other dietary factors. However, our results do not provide support for the hypothesis that consumption of contaminated sport fish increases the risk of colorectal cancer.

Dietary ω-3 Polyunsaturated Fatty Acids Inhibit Tumor Growth in Transgenic ApcMin/+ Mice, Correlating with CB1 Receptor Up-Regulation

Mediterranean diet components, such as olive oil and ω-3 polyunsaturated fatty acids (ω-3 PUFAs), can arrest cell growth and promote cell apoptosis. Recently, olive oil has been demonstrated to modulate type-1 cannabinoid (CB1) receptor gene expression in both human colon cancer cells and rat colon. The aim of this study was to investigate a possible link between olive oil and ω-3 PUFAs effects and CB1 receptor expression in both intestinal and adipose tissue of Apc^Min/+ mice. To confirm the role for the CB1 receptor as a negative modulator of cell proliferation in human colon cancer, CB1 receptor gene expression was also detected in tumor tissue and in surrounding normal mucosa of patients with colorectal cancer (CRC). Dietary ω-3 PUFAs significantly inhibited intestinal polyp growth in mice, correlating with CB1 receptor gene and protein expression induction. CB1 receptor gene up-regulation was also detected in adipose tissue, suggesting a close communication between cancer cells and the surrounding environment. Tissue CB1 receptor induction was associated with a concurrent inactivation of the Wnt/β-catenin pathway. Moreover, there was a significant reduction in CB1 receptor gene expression levels in cancer tissue compared to normal surrounding mucosa of patients with CRC, confirming that in cancer the “protective” action of the CB1 receptor is lost.

Adipose-derived human stem/stromal cells: comparative organ specific mitochondrial bioenergy profiles

Background

Adipose-derived stem/stromal cells (ASCs) isolated from the stromal vascular fraction are a source of mesenchymal stem cells that have been shown to be beneficial in many regenerative medicine applications. ASCs are an attractive source of stem cells in particular, due to their lack of immunogenicity. This study examines differences between mitochondrial bioenergetic profiles of ASCs isolated from adipose tissue of five peri-organ regions: pericardial, thymic, knee, shoulder, and abdomen.

Results

Flow cytometry showed that the majority of each ASC population isolated from the adipose tissue of 12 donors, with an n = 3 for each tissue type, were positive for MSC markers CD90, CD73, and CD105, and negative for hematopoietic markers CD34, CD11B, CD19, and CD45. Bioenergetic profiles were obtained for ASCs with an n = 4 for each tissue type and graphed together for comparison. Mitochondrial stress tests provided the following measurements: basal respiration rate (measured as oxygen consumption rate [pmol O₂/min], ATP production, proton leak, maximal respiration, respiratory control ratio, coupling efficiency, and non-mitochondrial respiration. Glycolytic stress tests provided the following measurements: basal glycolysis rate (measured as extracellular acidification rate [mpH/min]), glycolytic capacity, glycolytic reserve, and non-glycolytic acidification.

Conclusions

The main goal of this manuscript was to provide baseline reference values for future experiments and to compare bioenergetic potentials of ASCs isolated from adipose tissue harvested from different anatomical locations. Through an investigation of mitochondrial respiration and glycolysis, it was demonstrated that bioenergetic profiles do not significantly differ by region due to depot-dependent and donor-dependent variability. Thus, although the physiological function, microenvironment and anatomical harvest site may directly affect the characteristics of ASCs isolated from different organ regions, the ultimate utility of ASCs remains independent of the anatomical harvest site.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-3712-1) contains supplementary material, which is available to authorized users.

Obesity and cancer: the role of adipose tissue and adipo-cytokines-induced chronic inflammation

Adipose tissue in addition to its ability to keep lipids is now recognized as a real organ with both metabolic and endocrine functions. Recent studies demonstrated that in obese animals is established a status of adipocyte hypoxia and in this hypoxic state interaction between adipocytes and stromal vascular cells contribute to tumor development and progression. In several tumors such as breast, colon, liver and prostate, obesity represents a poor predictor of clinical outcomes. Dysfunctional adipose tissue in obesity releases a disturbed profile of adipokines with elevated levels of pro-inflammatory factors and a consequent alteration of key signaling mediators which may be an active local player in establishing the peritumoral environment promoting tumor growth and progression. Therefore, adipose tissue hypoxia might contribute to cancer risk in the obese population. To date the precise mechanisms behind this obesity-cancer link is not yet fully understood. In the light of information provided in this review that aims to identify the key mechanisms underlying the link between obesity and cancer we support that inflammatory state specific of obesity may be important in obesity-cancer link.

Leptin and insulin up-regulate miR-4443 to suppress NCOA1 and TRAF4, and decrease the invasiveness of human colon cancer cells

Background

Obesity is a risk factor for colorectal cancer (CRC). Normal and tumor cells respond to metabolic hormones, such as leptin and insulin. Thus, obesity-associated resistance to these hormones likely leads to changes in gene expression and behavior of tumor cells. However, the mechanisms affected by leptin and insulin signaling in CRC cells remain mostly unknown.

Methods

We hypothesized that microRNAs (miRNAs) are involved in the regulation of tumorigenesis-related gene expression in CRC cells by leptin and insulin. To test this hypothesis, miRNA levels in the CRC-derived cell lines HCT-116, HT-29 and DLD-1 were profiled, following leptin and insulin treatment. Candidate miRNAs were validated by RT-qPCR. Predicted miRNA targets with known roles in cancer, were validated by immunoblots and reporter assays in HCT-116 cells. Transfection of HCT-116 cells with candidate miRNA mimic was used to test in vitro effects on proliferation and invasion.

Results

Of ~800 miRNAs profiled, miR-4443 was consistently up-regulated by leptin and insulin in HCT-116 and HT-29, but not in DLD-1, which lacked normal leptin receptor expression. Dose response experiments showed that leptin at 100 ng/ml consistently up-regulated miR-4443 in HCT-116 cells, concomitantly with a significant decrease in cell invasion ability. Transfection with miR-4443 mimic decreased invasion and proliferation of HCT-116 cells. Moreover, leptin and miR-4443 transfection significantly down-regulated endogenous NCOA1 and TRAF4, both predicted targets of miR-4443 with known roles in cancer metastasis. miR-4443 was found to directly regulate TRAF4 and NCOA1, as validated by a reporter assay. The up-regulation of miR-4443 by leptin or insulin was attenuated by the inhibition of MEK1/2.

Conclusions

Our findings suggest that miR-4443 acts in a tumor-suppressive manner by down-regulating TRAF4 and NCOA1 downstream of MEK-C/EBP-mediated leptin and insulin signaling, and that insulin and/or leptin resistance (e.g. in obesity) may suppress this pathway and increase the risk of metastatic CRC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2938-1) contains supplementary material, which is available to authorized users.

Omentum and bone marrow: how adipocyte-rich organs create tumour microenvironments conducive for metastatic progression

A number of clinical studies have linked adiposity with increased cancer incidence, progression and metastasis, and adipose tissue is now being credited with both systemic and local effects on tumour development and survival. Adipocytes, a major component of benign adipose tissue, represent a significant source of lipids, cytokines and adipokines, and their presence in the tumour microenvironment substantially affects cellular trafficking, signalling and metabolism. Cancers that have a high predisposition to metastasize to the adipocyte-rich host organs are likely to be particularly affected by the presence of adipocytes. Although our understanding of how adipocytes influence tumour progression has grown significantly over the last several years, the mechanisms by which adipocytes regulate the metastatic niche are not well-understood. In this review, we focus on the omentum, a visceral white adipose tissue depot, and the bone, a depot for marrow adipose tissue, as two distinct adipocyte-rich organs that share common characteristic: they are both sites of significant metastatic growth. We highlight major differences in origin and function of each of these adipose depots and reveal potential common characteristics that make them environments that are attractive and conducive to secondary tumour growth. Special attention is given to how omental and marrow adipocytes modulate the tumour microenvironment by promoting angiogenesis, affecting immune cells and altering metabolism to support growth and survival of metastatic cancer cells.

Dietary olive oil induces cannabinoid CB2 receptor expression in adipose tissue of ApcMin/+ transgenic mice

BACKGROUND: Cannabinoid- 2 (CB2) receptor is known for its anti-obesity effects silencing the activated immune cells that are key drivers of metabolic syndrome and inflammation. Nutritional interventions in experimental models of carcinogenesis have been demonstrated to modulate tissue inflammation state and proliferation.

OBJECTIVE: Aim of this study was to test, in Apc^Min/+ mice, whether a diet enriched with olive oil, omega- 3 and omega-6- PUFAs affects the adipose tissue inflammation status.

METHODS: Four groups of animal were studied: ST group, receiving a standard diet; OO group, receiving the standard diet in which soybean oil (source of fats) was replaced with olive oil; OM-3 group, receiving the standard diet in which soybean oil was replaced with salmon oil; OM-6 group, receiving the standard diet in which soybean oil was replaced with oenothera oil. Gene and protein expression, in adipose tissue, were evaluated by RT-PCR and Western Blotting, respectively. Enzymatic activities were assayed by fluorescent and radiometric method, where appropriated.

RESULTS: The diet enriched with olive oil significantly induced CB2 receptor expression and it was able to control inflammatory and proliferative activity of mice adipose tissue.

CONCLUSIONS: The present findings open opportunities for developing novel nutritional strategies considering olive oil a key ingredient of a healthy dietary pattern.

Mechanisms linking obesity to altered metabolism in mice colon carcinogenesis

There are an increasing number of reports on obesity being a key risk factor for the development of colon cancer. Our goal in this study was to explore the metabolic networks and molecular signaling pathways linking obesity, adipose tissue and colon cancer. Using in-vivo experiments, we found that mice fed a high-fat diet (HFD) and injected with MC38 colon cancer cells develop significantly larger tumors than their counterparts fed a control diet. In ex-vivo experiments, MC38 and CT26 colon cancer cells exposed to conditioned media (CM) from the adipose tissue of HFD-fed mice demonstrated significantly lower oxygen consumption rate as well as lower maximal oxygen consumption rate after carbonyl cyanide-4-trifluoromethoxy-phenylhydrazone treatment. In addition, in-vitro assays showed downregulated expression of mitochondrial genes in colon cancer cells exposed to CM prepared from the visceral fat of HFD-fed mice or to leptin. Interestingly, leptin levels detected in the media of adipose tissue explants co-cultured with MC38 cancer cells were higher than in adipose tissue explants cultures, indicating cross talk between the adipose tissue and the cancer cells. Salient findings of the present study demonstrate that this crosstalk is mediated at least partially by the JNK/STAT3-signaling pathway.

Hydroxytyrosol Inhibits Cannabinoid CB1 Receptor Gene Expression in 3T3-L1 Preadipocyte Cell Line

The 3T3-L1 preadipocyte cell line is a well characterized cell model for studying the adipocyte status and the molecular mechanisms involved in differentiation of these cells. 3T3-L1 preadipocytes have the ability to synthesize and degrade endocannabinoid anandamide (AEA) and their differentiation into adipocytes increases the expression of cannabinoid (CB1) and PPAR-γ receptors. Clinically, the blocking stimulation of the endocannabinoid pathway has been one of the first approaches proposed to counteract the obesity and obesity-associated diseases (such as diabetes, metabolic syndrome and cancer). In this connection, here we studied in cultured 3T3-L1 pre-adipocytes the effects of n-3-PUFA, α-Linolenic acid (OM-3), n-6-PUFA, Linoleic acid (OM-6), and hydroxytyrosol (HT) on the expression of CB1 receptor gene and the adipogenesis-related genes PPAR-γ, Fatty Acid Synthase (FAS) and Lipoprotein Lipase (LPL). HT was able to inhibit 3T3-L1 cell differentiation by down-regulating cell proliferation and CB1 receptor gene expression. HT exhibited anti-adipogenic effects, whereas OM-3 and OM-6 exerted an inhibitory action on cell proliferation associated with an induction of the preadipocytes differentiation and CB1 receptor gene expression. Moreover, the expression of FAS and LPL genes resulted increased after treatment with both HT and OM-3 and OM-6. The present study points out that the intake of molecules such as HT, contained in extra virgin olive oil, may be considered also in view of antiobesity and antineoplastic properties by acting directly on the adipose tissue and modulating CB1 receptor gene transcription.

New 3D-Culture Approaches to Study Interactions of Bone Marrow Adipocytes with Metastatic Prostate Cancer Cells

Adipocytes are a major component of the bone marrow that can critically affect metastatic progression in bone. Understanding how the marrow fat cells influence growth, behavior, and survival of tumor cells requires utilization of in vitro cell systems that can closely mimic the physiological microenvironment. Herein, we present two new three-dimensional (3D) culture approaches to study adipocyte-tumor cell interactions in vitro. The first is a transwell-based system composed of the marrow-derived adipocytes in 3D collagen I gels and reconstituted basement membrane-overlayed prostate tumor cell spheroids. Tumor cells cultured under these 3D conditions are continuously exposed to adipocyte-derived factors, and their response can be evaluated by morphological and immunohistochemical analyses. We show via immunofluorescence analysis of metabolism-associated proteins that under 3D conditions tumor cells have significantly different metabolic response to adipocytes than tumor cells grown in 2D culture. We also demonstrate that this model allows for incorporation of other cell types, such as bone marrow macrophages, and utilization of dye-quenched collagen substrates for examination of proteolysis-driven responses to adipocyte- and macrophage-derived factors. Our second 3D culture system is designed to study tumor cell invasion toward the adipocytes and the consequent interaction between the two cell types. In this model, marrow adipocytes are separated from the fluorescently labeled tumor cells by a layer of collagen I. At designated time points, adipocytes are stained with BODIPY and confocal z-stacks are taken through the depth of the entire culture to determine the distance traveled between the two cell types over time. We demonstrate that this system can be utilized to study effects of candidate factors on tumor invasion toward the adipocytes. We also show that immunohistochemical analyses can be performed to evaluate the impact of direct interaction of prostate tumor cells with adipocytes. Our models underline the importance of using the appropriate culture conditions to mimic physiological interactions between marrow adipocytes and metastatic tumor cells. These systems have a potential to be utilized for analyses of various factors that may be regulated by the adipocytes in bone. Their application likely extends beyond metastatic prostate cancer to other tumors that colonize the bone marrow microenvironment.

Advances and perspectives of colorectal cancer stem cell vaccine

Colorectal cancer is essentially an environmental and genetic disease featured by uncontrolled cell growth and the capability to invade other parts of the body by forming metastases, which inconvertibly cause great damage to tissues and organs. It has become one of the leading causes of cancer-related mortality in the developed countries such as United States, and approximately 1.2 million new cases are yearly diagnosed worldwide, with the death rate of more than 600,000 annually and incidence rates are increasing in most developing countries. Apart from the generally accepted theory that pathogenesis of colorectal cancer consists of genetic mutation of a certain target cell and diversifications in tumor microenvironment, the colorectal cancer stem cells (CCSCs) theory makes a different explanation, stating that among millions of colon cancer cells there is a specific and scanty cellular population which possess the capability of self-renewal, differentiation and strong oncogenicity, and is tightly responsible for drug resistance and tumor metastasis. Based on these characteristics, CCSCs are becoming a novel target cells both in the clinical and the basic studies, especially the study of CCSCs vaccines due to induced efficient immune response against CCSCs. This review provides an overview of CCSCs and preparation technics and targeting factors related to CCSCs vaccines in detail.

Adipose tissue macrophage polarization by intermittent hypoxia in a mouse model of OSA: effect of tumor microenvironment

Intermittent hypoxia (IH)-induces alterations in tumor-associated macrophages (TAMs) that are associated with adverse cancer outcomes, as reported in patients suffering from sleep apnea. Adipose tissues (AT) and bone-marrow (BM)-derived cells are the inferred sources of macrophages infiltrating malignant tumors. Here, the sources of TAMs and the phenotypic changes induced by IH in the ipsilateral and contralateral AT were investigated by using a syngeneic murine solid tumor model (TC1). C57/B6 male mice were exposed to either IH or room air (RA) for 6 weeks, with TC1 cells being inoculated in the 2nd week. Macrophage content, phenotype and tissue origin were assessed in tumors, and ipsilateral and contralateral AT. IH induced a ~2.2-fold increase in TAM tumor infiltration. However, differential responses in the tumor ipsilateral and contralateral AT emerged: IH increased infiltration of preferentially M1 macrophages in contralateral AT, while reductions in macrophages emerged in ipsilateral AT and primarily consisted of the M2 phenotype. These changes were accompanied by reciprocal increases in resident and BM-derived TAMs in the tumor. IH-induced phenotypic alterations in AT macrophages surrounding the tumor and their increased infiltration within the tumor may contribute to the accelerated tumor progression associated with IH.