Effects of reduced dietary linoleic acid intake, alone or combined with an algal source of docosahexaenoic acid, on MDA-MB-231 breast cancer cell growth and apoptosis in nude mice

Effects of Tributyrin Supplementation on Liver Fat Deposition, Lipid Levels and Lipid Metabolism-Related Gene Expression in Broiler Chickens

The objective of this study was to investigate the effects of tributyrin supplementation on liver fat metabolism in broiler chickens. Two hundred and forty broilers were randomly allocated into two experimental groups (6 replicates per treatment; 20 chickens in each replicate): the control group (CN), which received a basal diet, and the tributyrin group (TB), which received a basal diet supplemented with 1 g/kg of tributyrin. The experimental period lasted 37 days. The results showed that in the liver, broilers supplemented with tributyrin had higher content of high-density lipoprotein cholesterol (HDL-C) (p < 0.05). Liver hepatic lipase (HL), lipoprotein lipase (LPL) and total lipid (TL) activity were significantly lower than in the TB group than that in the NC group. Meanwhile, the diet supplemented with tributyrin had more lipid droplets than the NC group, whereas the TB and NC groups showed no histological abnormalities in the liver. Furthermore, the mRNA expression levels of peroxisome proliferators-activated receptor α (PPARα), proliferators-activated receptor γ (PPARγ), fatty acid synthase (FAS), LPL and adipose triglyceride lipase (ATGL) in the liver were significantly upregulated in the TB group (p < 0.05), while those of the long-chain acyl-CoA-synthetase 1 (ACSL1) mRNA between the TB group and the NC group were not different (p > 0.05). These findings indicated that the diet supplemented with tributyrin could increase fat deposition appropriately by promoting fat synthesis without causing liver tissue damage, which demonstrated that tributyrin can be considered a valid feed additive for broiler chickens.

Docosahexaenoic acid monoglyceride induces apoptosis and autophagy in breast cancer cells via lipid peroxidation-mediated endoplasmic reticulum stress

Epidemiologic and preclinical studieshave shown that marine n-3 polyunsaturated fatty acids (n-3 PUFAs) elicit promising chemoprevention against breast cancer. Docosahexaenoic acid monoglyceride (MAG-DHA), a docosahexaenoic acid sn-1-monoacylglycerol does not required pancreatic lipase to be absorbed, eliciting a better bioavailability when compared with other formulations such as DHA-free fatty acid, DHA-triglycerol, or DHA-ethyl ester. However, the anticancer actions and underlying mechanisms of MAG-DHA on breast cancer remain to be assessed. In this study, MAG-DHA induced significant growth inhibition in MCF-7 and MDA-MB-231 breast cancer cells in a dose-dependent manner. MAG-DHA treatment (80 µM) led to 83.8 and 94.3% growth inhibition between MCF-7 and MDA-MB-231 cells, respectively. MAG-DHA-induced growth inhibition was tightly associated with apoptosis, as evidenced by increased active forms of caspase-3, poly (ADP-ribose) polymerase (PARP) and caspase-12. In particular, MAG-DHA-induced apoptosis was triggered by oxidative stress-mediated endoplasmic reticulum (ER) stress, as evidenced by activation of the PERK-eIF2α pathway in ER. MAG-DHA treatment also strongly suppressed the growth of E0771 murine breast cancer xenografts, significant differences of tumor volume were found between MAG-DHA group (0.271 cm³ ) and control group (0.875 cm³ ) after 15 daily MAG-DHA treatments. The in vitro antibreast cancer mechanism of MAG-DHA was supported by the in vivo xenograft model. In addition, MAG-DHA-induced ER stress concomitantly triggered autophagy in these cancer cells, and the induction of autophagy suppressed its ability to induce apoptotic cell death. Our data suggested that MAG-DHA as dietary supplement, in combination with autophagy inhibitors may be a useful therapeutic strategy in treating breast cancer.

Role of dietary fat on obesity-related postmenopausal breast cancer: insights from mouse models and methodological considerations

The increasing incidence rate of breast cancer in the last few decades is known to be linked to the upward trend of obesity prevalence worldwide. The consumption of high-fat diet in particular has been correlated with postmenopausal breast cancer risk. The underlying mechanisms, using suitable and reliable experimental mouse model, however, is lacking. The current review aims to discuss the evidence available from mouse models on the effects of dietary fats intake on postmenopausal breast cancer. We will further discuss the biochemical mechanisms involved in the occurrence of postmenopausal breast cancer. In addition, the methodological considerations and their limitations in obesity-related postmenopausal breast cancer, such as choice of mouse models and breast cancer cell lines as well as the study duration will be reviewed. The current review will provide a platform for further development of new xenograft models which may offer the opportunity to investigate the mechanisms of postmenopausal breast cancer in a greater detail.

Targeting ferroptosis in breast cancer

Ferroptosis is a recently discovered distinct type of regulated cell death caused by the accumulation of lipid-based ROS. Metabolism and expression of specific genes affect the occurrence of ferroptosis, making it a promising therapeutic target to manage cancer. Here, we describe the current status of ferroptosis studies in breast cancer and trace the key regulators of ferroptosis back to previous studies. We also compare ferroptosis to common regulated cell death patterns and discuss the sensitivity to ferroptosis in different subtypes of breast cancer. We propose that viewing ferroptosis-related studies from a historical angle will accelerate the development of ferroptosis-based biomarkers and therapeutic strategies in breast cancer.

The Effect of Omega-3 Polyunsaturated Fatty Acid Supplementations on anti-Tumor Drugs in Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) comprises about 10-20% of all diagnosed breast cancers. Increasing evidence shows that the omega-3 polyunsaturated fatty acids (ω-3PUFAs), docosahexaenoic acid and eicosapentaenoic acid, can influence the development, progression, and prognosis of TNBC In Vivo and In Vitro; however, clinical evidence supporting the effect of ω-3PUFAs on TNBC is lacking. Research has demonstrated that ω-3PUFAs can induce apoptosis in breast cancer cells by inhibiting the PI3K/AKT signal transduction pathway, and that ω-3PUFAs can improve the effectiveness of chemotherapy drugs. Using ω-3PUFA supplementation in addition to pharmacotherapy in the treatment of breast cancer may result in enhanced anti-tumor effects that will be particularly applicable to difficult to treat phenotypes such as TNBC. The aim of the current review was to summarize the evidence-base supporting the antitumor effects of omega-3 PUFAs in TNBC.

Breast Cancer and Dietary Fat Intake: A correlational study

Background:

Breast cancer (BC) is reported to be the most common malignancies affecting women worldwide. There is a sharp increase in the BC incidence rate over the past three decades as previously low risk countries are moving towards high -calorie western diets. Few epidemiologic studies along with animal experiments have ascertained the role of dietary fat in developing BC. This study aimed to determine the correlation between per capita dietary fat consumption and incidence of BC.

Methods:

Three major data bases were used to conduct this correlational study. The data regarding consumption of fat and breast cancer incidence from 88 countries across five continents were extracted. The correlation coefficients between the incidence of BC and the fat consumption from the year 1990 to 2007 were calculated.

Results:

A statistically significant (P<0.001) correlation between the average fat consumption and the crude BC incidence rate was observed and was more than 0.6, clearly indicating that there is a moderate to strong correlation with fat consumption and incidence of breast cancer (P<0.001).

Conclusions:

Our observation indicated that increased total fat consumption increases the risk of developing BC. Consumption of dietary fat increases obesity thereby, increasing the risk of BC development. Dietary fat gets stored in the body since they undergo minimum oxidation as compared to carbohydrates and protein thereby, contributing to obesity a known risk factors for BC. Current study strengthens the evidence to support the hypothesis that non-genetic factors contribute to the occurrence of this disease.

Treatment with DHA Modifies the Response of MDA-MB-231 Breast Cancer Cells and Tumors from nu/nu Mice to Doxorubicin through Apoptosis and Cell Cycle Arrest

Background

Docosahexaenoic acid (DHA) has been shown to reduce growth of breast cancer cells in vitro and in vivo; it may also benefit the action of cytotoxic cancer drugs. The mechanisms for these observations are not completely understood.

Objectives

We sought to explore how pretreatment of MDA-MB-231 breast cancer cells with DHA alters gene expression with doxorubicin (DOX) treatment and confirm that feeding DHA to tumor-bearing nu/nu mice improves the efficacy of DOX.

Methods

MDA-MB-231 cells were subjected to 4 conditions: a control mixture of 40 μM linoleic and 40 μM oleic acid (OALA), DHA (60 μM plus OALA), OALA DOX (0.41 μM), or DHA DOX (plus OALA) and assessed for effects on viability and function. Female nu/nu mice (6 wk old) bearing MDA-MB-231 tumors were randomly assigned to a nutritionally complete diet (20 g ± 2.8 g DHA/100 g diet) containing a polyunsaturated:saturated fat ratio of 0.5, with or without injections 2 times/wk of 5 mg DOX/kg for 4 wk.

Results

Microarray and protein analysis indicated that DHA DOX cells, compared with OALA DOX, had upregulated expression of apoptosis genes, Caspase-10 (1.3-fold), Caspase-9 (1.4-fold), and Receptor (TNFRSF)-interacting serine-threonine kinase 1 (RIPK1) (1.2-fold), while downregulating cell cycle genes, Cyclin B1 (-2.1-fold), WEE1 (-1.6-fold), and cell division cycle 25 homolog C (CDC25C) (-1.8-fold) (P < 0.05). DHA DOX-treated mice had 50% smaller tumors than control mice (P < 0.05). Analysis of proapoptotic proteins from tumors of DHA DOX mice showed increased Caspase-10 (by 68%) and BH3 interacting domain death agonist (Bid) (by 50%), decreased B-cell CLL/lymphoma 2 (BCL2) (by 24%), and decreased cell cycle proteins Cyclin B1 and Cdc25c (both by 42%), compared with control mice (P < 0.05).

Conclusions

Supplementation with DHA facilitates the action of DOX in MDA-MB-231 cells and in nu/nu mice, which may occur via amplification of the effect of DOX on apoptosis and cell cycle genes.

Metabolome-wide association study identified the association between a circulating polyunsaturated fatty acids variant rs174548 and lung cancer

Quantitative trait loci (QTLs) are widely used as instruments to infer causal risk factors of diseases based on the idea of mendelian randomization. Plasma metabolites can serve as risk factors of cancer, and the heritability of many circulating metabolites was high. We conducted a metabolome-wide association study (MWAS) to systematically investigate the effects of genetic variants on metabolites and lung cancer based on published genome-wide association study (GWASs) and metabolic-QTL (mQTL) study. Then we confirmed the results by subsequent genetic and metabolic validations and inferred the causal relationship between identified metabolites and lung cancer through genetic variant(s). We firstly identified six polyunsaturated fatty acids (PUFAs) represented by rs174548-linked haplotype were significantly associated with lung cancer risk in a Chinese GWAS (2311 cases and 3077 controls). Rs174548 was further confirmed to be associated with lung cancer in 13 821 Europeans and 18 471 Asians (ORmeta = 0.87, Pmeta = 1.76 × 10-15) and the effect was much stronger in females (Pinteraction = 6.00 × 10-4). We next validated rs174548-plasma PUFA association in 253 Chinese subjects (β = -0.57, P = 1.68 × 10-3). Rs174548 was also found associated with FADS1 (the major fatty acid desaturase of identified PUFAs) expression in liver tissues. Taken together, we found that rs174548 was associated with both PUFAs and lung cancer. Because rs174548 was the only mQTL variant of PUFAs reported by previous GWASs and explained a large proportion of heritability, we proposed that plasma PUFAs could be causally associated with lung cancer based on the idea of mendelian randomization. These findings provide a diet-related risk factor and may have important implications for prevention on lung cancer.

Long-chain n-3 PUFA against breast and prostate cancer: Which are the appropriate doses for intervention studies in animals and humans?

The potential antineoplastic effect of the long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) remains a highly controversial issue. Numerous animal studies have supported the anticancer role of these dietary fatty acids, whereas conflicting results have been obtained in population studies, and only a few intervention human trials have been so far performed. In view of the possibility that the anticancer effects may be maximally observed within a defined range of EPA and DHA doses, herein we critically review the results and doses used in both animal studies and human clinical trials focusing on the possible n-3 PUFA protective effects against breast and prostate cancer. Our main aim is to identify the EPA and/or DHA ranges of doses needed to obtain clear anticancer effects. This may be of great help in designing future animal studies, and also in understanding the most appropriate dose for further human intervention studies. Moreover, since the healthy effects of these fatty acids have been strictly related to their increased incorporation in plasma and tissue lipids, we also examine and discuss the incorporation changes following the administration of the effective anticancer EPA and/or DHA doses in animals and humans.

Docosahexaenoic acid-acylated phloridzin, a novel polyphenol fatty acid ester derivative, is cytotoxic to breast cancer cells

Docosahexaenoic acid-acylated phloridzin (PZ-DHA), a novel polyphenol fatty acid ester derivative, was synthesized through a regioselective acylation reaction with the aim of increasing the bioactivity of phloridzin (PZ) and docosahexaenoic acid (DHA). In this study, PZ-DHA's cytotoxic activity was explored using in vitro and in vivo models of mammary carcinoma. PZ-DHA was selectively cytotoxic for mammary carcinoma (MDA-MB-231, MDA-MB-468, 4T1, MCF-7 and T-47D) cells compared to non-malignant human mammary epithelial cells (HMEC and MCF-10A) and fibroblasts by MTS assay and Annexin-V-FLUOS/propidium iodide staining. Flow cytometric analysis of Oregon Green 488- and Ki-67-stained MDA-MB-231 cells showed antiproliferative activity of PZ-DHA at a subcytotoxic concentration. PZ-DHA also arrested MDA-MB-231 cell division at the G2/M phase and down-regulated expression of cyclin B1 and cyclin-dependent kinase 1 (CDK1). PZ-DHA-induced apoptosis in MDA-MB-231 cells was confirmed by caspase 3/7 activation in a luminescence assay and DNA fragmentation by TUNEL staining. Moreover, MDA-MB-231 xenograft growth in non-obese diabetic severe combined immunodeficient mice was suppressed by intra-tumoral administration of PZ-DHA. This study shows that PZ-DHA is selectively cytotoxic to breast cancer cells in vitro and in vivo, suggesting that further investigations of PZ-DHA are warranted as a potential treatment for breast cancer.

Lower ω-6/ω-3 Polyunsaturated Fatty Acid Ratios Decrease Fat Deposition by Inhibiting Fat Synthesis in Gosling

The objective of the current study was to investigate the effects of dietary ω-6/ω-3 polyunsaturated fatty acid (PUFA) ratios on lipid metabolism in goslings. One hundred and sixty 21-day-old Yangzhou geese of similar weight were randomly divided into 4 groups. They were fed different PUFA-supplemented diets (the 4 diets had ω-6/ω-3 PUFA ratios of 12:1, 9:1, 6:1, or 3:1). The geese were slaughtered and samples of liver and muscle were collected at day 70. The activities and the gene expression of enzymes involved in lipid metabolism were measured. The results show that the activities of acetyl coenzyme A carboxylase (ACC), malic enzyme (ME), and fatty acid synthase (FAS) were lower (p<0.05), but the activities of hepatic lipase (HL) and lipoprotein lipase (LPL) were higher (p<0.05), in the liver and the muscle from the 3:1 and 6:1 groups compared with those in the 9:1 and 12:1 groups. Expression of the genes for FAS (p<0.01), ME (p<0.01) and ACC (p<0.05) were higher in the muscle of groups fed diets with higher ω-6/ω-3 PUFA ratios. Additionally, in situ hybridization tests showed that the expression intensities of the high density lipoprotein (HDL-R) gene in the 12:1 and 9:1 groups were significantly lower (p<0.01) than that of the 3:1 group in the muscle of goslings. In conclusion, diets containing lower ω-6/ω-3 PUFA ratios (3:1 or 6:1) could decrease fat deposition by inhibiting fat synthesis in goslings.

Enhanced anticancer properties of lomustine in conjunction with docosahexaenoic acid in glioblastoma cell lines

OBJECT

Glioblastoma is a rapidly infiltrating tumor that consistently rematerializes despite various forms of aggressive treatment. Brain tumors are commonly treated with alkylating drugs, such as lomustine, which are chemotherapeutic agents. Use of these drugs, however, is associated with serious side effects. To reduce the side effects, one approach is to combine lower doses of chemotherapeutic drugs with other nontoxic anticancer agents. In this study, using glioblastoma cell lines, the authors investigated the anticancer effects of lomustine, alone and in combination with docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid normally abundant in the brain and known for its anticancer potential.

METHODS

Cells were cultured from 3 human-derived tumor cell lines (U87-MG, DB029, and MHBT161) and supplemented with either DHA or lomustine to determine the growth inhibitory potential using WST-1, a mitochondrial functional indicator. Human-derived cerebral cortex microvascular endothelial cells served as a normal phenotypic control. Cellular incorporation of DHA was analyzed by gas chromatography. Using flow cytometric analysis, the DHA and/or lomustine effect on induction of apoptosis and/or necrosis was quantified; subsequently, the DHA and lomustine effect on cell cycle progression was also assessed. Western blot analysis confirmed the role of downstream cellular targets.

RESULTS

U87-MG growth was inhibited with the supplementation of either DHA (ED50 68.3 μM) or lomustine (ED50 68.1 μM); however, growth inhibition was enhanced when U87-MG cells were administered equimolar doses of each compound, resulting in nearly total growth inhibition at 50 μM. Gas chromatography analysis of the fatty acid profile in DHA-supplemented U87-MG cells resulted in a linear dose-dependent increase in DHA incorporation (< 60 μM). The combination of DHA and lomustine potently induced U87-MG apoptosis and necrosis as indicated by flow cytometric analysis. Activation of caspase-3 and poly (ADP-ribose) polymerase (PARP) was evident in lomustine-treated U87-MG cells, although this activation did not appear to be dependent on DHA supplementation. Additionally, lomustine-treated cells' growth arrested in the G2/M cell cycle stage, regardless of the presence of DHA. Similar to the U87-MG observations, the combination of DHA and lomustine resulted in growth inhibition of 2 additional human-derived glioblastoma cell lines, DB029 and MHBT161. Importantly, in primary human-derived cerebral cortex endothelial cells, this combination was only growth inhibitory (40.8%) at the highest dose screened (100 μM), which indicates a certain degree of selectivity toward glioblastoma.

CONCLUSIONS

Taken together, these data suggest a potential role for a combination therapy of lomustine and DHA for the treatment of glioblastomas.

The role of n-3 polyunsaturated fatty acids in the prevention and treatment of breast cancer

Breast cancer (BC) is the most common cancer among women worldwide. Dietary fatty acids, especially n-3 polyunsaturated fatty acids (PUFA), are believed to play a role in reducing BC risk. Evidence has shown that fish consumption or intake of long-chain n-3 PUFA, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are beneficial for inhibiting mammary carcinogenesis. The evidence regarding α-linolenic acid (ALA), however, remains equivocal. It is essential to clarify the relation between ALA and cancer since ALA is the principal source of n-3 PUFA in the Western diet and the conversion of ALA to EPA and DHA is not efficient in humans. In addition, the specific anticancer roles of individual n-3 PUFA, alone, have not yet been identified. Therefore, the present review evaluates ALA, EPA and DHA consumed individually as well as in n-3 PUFA mixtures. Also, their role in the prevention of BC and potential anticancer mechanisms of action are examined. Overall, this review suggests that each n-3 PUFA has promising anticancer effects and warrants further research.

n-3 polyunsaturated fatty acids and mechanisms to mitigate inflammatory paracrine signaling in obesity-associated breast cancer

Globally, the prevalence of obesity is increasing which subsequently increases the risk of the development of obesity-related chronic diseases. Low-grade chronic inflammation and dysregulated adipose tissue inflammatory mediator/adipokine secretion are well-established in obesity, and these factors increase the risk of developing inflammation-associated cancer. Breast cancer is of particular interest given that increased inflammation within the subcutaneous mammary adipose tissue depot can alter the local tissue inflammatory microenvironment such that it resembles that of obese visceral adipose tissue. Therefore, in obese women with breast cancer, increased inflammatory mediators both locally and systemically can perpetuate inflammation-associated pro-carcinogenic signaling pathways, thereby increasing disease severity. Herein, we discuss some of these inflammation-associated pro-carcinogenic mechanisms of the combined obese breast cancer phenotype and offer evidence that dietary long chain n-3 polyunsaturated fatty acids (PUFA) may have utility in mitigating the severity of obesity-associated inflammation and breast cancer.

Drug delivery design for intravenous route with integrated physicochemistry, pharmacokinetics and pharmacodynamics: illustration with the case of taxane therapeutics

This review is aimed at combining the published data on taxane formulations into a generalized Drug Delivery approach, starting from the physicochemistry and assessing its relationships with the pharmacokinetics, the biodistribution and the pharmacodynamics. Owing to the number and variety of taxane formulation designs, we considered this class of cytotoxic anticancer agents of particular interest to illustrate the concepts attached to this approach. According to the history of taxane development, we propose a classification as (i) "surfactant-based formulations" first generation, (ii) "surfactant-free formulations" second generation and (iii) "modulated pharmacokinetics drug delivery systems" third generation. Since our objective was to make the link between (i) the physicochemistry of the drug and carrier and (ii) the efficacy and safety of the drug in preclinical animal models and (iii) in human, we focused on the drug delivery technologies that were tested in clinic.

Characterization of synergistic anti-cancer effects of docosahexaenoic acid and curcumin on DMBA-induced mammary tumorigenesis in mice

BACKGROUND

The major obstacles to the successful use of individual nutritional compounds as preventive or therapeutic agents are their efficacy and bioavailability. One approach to overcoming this problem is to use combinations of nutrients to induce synergistic effects. The objective of this research was to investigate the synergistic effects of two dietary components: docosahexaenoic acid (DHA), an omega-3 fatty acid present in cold-water fish, and curcumin (CCM), an herbal nutrient present in turmeric, in an in vivo model of DMBA-induced mammary tumorigenesis in mice.

METHODS

We used the carcinogen DMBA to induce breast tumors in SENCAR mice on control, CCM, DHA, or DHA + CCM diets. Appearance and tumor progression were monitored daily. The tumors were harvested 15 days following their first appearance for morphological and immunohistological analysis. Western analysis was performed to determine expression of maspin and survivin in the tumor tissues. Characterization of tumor growth was analyzed using appropriate statistical methods. Otherwise all other results are reported as mean ± SD and analyzed with one-way ANOVA and Tukey's post hoc procedure.

RESULTS

Analysis of gene microarray data indicates that combined treatment with DHA + CCM altered the profile of "PAM50" genes in the SK-BR-3 cell line from an ER⁻/Her-2⁺ to that resembling a "normal-like" phenotype. The in vivo studies demonstrated that DHA + CCM treatment reduced the incidence of breast tumors, delayed tumor initiation, and reduced progression of tumor growth. Dietary treatment had no effect on breast size development, but tumors from mice on a control diet (untreated) were less differentiated than tumors from mice fed CCM or DHA + CCM diets. The synergistic effects also led to increased expression of the pro-apoptotic protein, maspin, but reduced expression of the anti-apoptotic protein, survivin.

CONCLUSIONS

The SK-BR-3 cells and DMBA-induced tumors, both with an ER⁻ and Her-2⁺ phenotype, were affected by the synergistic interaction of DHA and CCM. This suggests that the specific breast cancer phenotype is an important factor for predicting efficacy of these nutraceuticals. The combination of DHA and CCM is potentially a dietary supplemental treatment for some breast cancers, likely dependent upon the molecular phenotype of the cancer.

Fish oil decreases C-reactive protein/albumin ratio improving nutritional prognosis and plasma fatty acid profile in colorectal cancer patients

Previous studies have shown that n-3 polyunsaturated fatty acids n-3 (n-3 PUFA) have several anticancer effects, especially attributed to their ability to modulate a variety of genomic and immune responses. In this context, this randomized, prospective, controlled clinical trial was conducted in order to check whether supplementation of 2 g/day of fish oil for 9 weeks alters the production of inflammatory markers, the plasma fatty acid profile and the nutritional status in patients with colorectal cancer (CRC). Eleven adults with CRC in chemotherapy were randomized into two groups: (a) supplemented (SG) daily with 2 g/day of encapsulated fish oil [providing 600 mg/day of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)] for 9 weeks (n = 6), and (b) control (CG) (n = 5). All outcomes were evaluated on the day before the first chemotherapy session and 9 weeks later. Plasma TNF-α, IL-1β, IL-10 and IL-17A, the pro/anti-inflammatory balance (ratio TNF-α/IL-10 and IL-1β/IL10) and serum albumin, showed no significant changes between times and study groups (p > 0.05). C-reactive protein (CRP) and the CRP/albumin ratio showed opposite behavior in groups, significantly reducing their values in SG (p < 0.05). Plasma proportions of EPA and DHA increased 1.8 and 1.4 times, respectively, while the ARA reduced approximately 0.6 times with the supplementation (9 weeks vs baseline, p < 0.05). Patients from SG gained 1.2 kg (median) while the CG lost -0.5 kg (median) during the 9 weeks of chemotherapy (p = 0.72). These results demonstrate that 2 g/day of fish oil for 9 weeks of chemotherapy improves CRP values, CRP/albumin status, plasma fatty acid profile and potentially prevents weight loss during treatment.

Dietary fat in breast cancer survival

Laboratory evidence suggests a plausible role for dietary fat in breast cancer pathophysiology. We conducted a systematic literature review to assess the epidemiological evidence on the impact of total dietary fat and fat subtypes, measured pre- and/or postcancer diagnosis, in relation to breast cancer-specific and all-cause mortality among breast cancer survivors. Studies were included if they were in English, had a sample size ≥200, and presented the hazard ratio/rate ratio for recurrence, disease-specific mortality, or all-cause mortality (n = 18). Although the results are mixed, most studies suggested that higher saturated fat intake prediagnosis was associated with increased risk of breast cancer-specific and all-cause mortality. Postdiagnostic trans fat intake was associated with a 45% and 78% increased risk of all-cause mortality. Higher monounsaturated fat intake before and after diagnosis was generally associated with increased risk of all-cause and breast cancer-specific mortality, albeit the majority of the studies were statistically nonsignificant. Two studies evaluating omega-3 fat intake suggested an inverse association with all-cause mortality. Although there were too few studies on fat subtypes to draw definitive conclusions, high consumption of saturated fat may exert a detrimental effect on breast cancer-specific and all-cause mortality, whereas omega-3 fat may be beneficial. The inconsistent and limited evidence warrants research to assess the impact of consumption of fat subtypes on breast cancer recurrence and mortality.

n-3 Polyunsaturated fatty acids throughout the cancer trajectory: influence on disease incidence, progression, response to therapy and cancer-associated cachexia

Evidence from epidemiological studies suggests that diets rich in n-3 PUFA may be associated with reduced cancer risk. These observations have formed the rationale for exploring the mechanisms by which n-3 PUFA may be chemoprotective and have resulted in significant advances in our mechanistic understanding of n-3 PUFA action on tumour growth. Various interrelated and integrated mechanisms may be at work by which n-3 PUFA influence cancer at all stages of initiation, promotion, progression, and neoplastic transformation. More recently, experimental studies have reported enhanced tumour cell death with chemotherapy when fish oil is provided while toxic side effects to the host are reduced. Furthermore, cancer-associated wasting has been shown to be attenuated by fish oil supplementation. Clinical evidence suggests that the n-3 PUFA status of newly diagnosed cancer patients and individuals undergoing chemotherapy is low. Therefore, both the disease itself and therapeutic treatments may be contributing factors in the decline of n-3 PUFA status. Dietary supplementation to maintain and replenish n-3 PUFA status at key points in the cancer disease trajectory may provide additional health benefits and an enhanced quality of life. The present review will focus on and critically examine current research efforts related to the putative anti-cancer effects of n-3 PUFA and their suggested ability to palliate cancer-associated and treatment-associated symptoms.

The janus face of lipids in human breast cancer: how polyunsaturated Fatty acids affect tumor cell hallmarks

For several years, lipids and especially n - 3 and n - 6 polyunsaturated fatty acids (PUFAs) receive much attention in human health. Epidemiological studies tend to correlate a PUFA-rich diet with a reduced incidence of cancer, including breast cancer. However, the molecular and cellular mechanisms supporting the effect of PUFAs in breast cancer cells remain relatively unknown. Here, we review some recent progress in understanding the impact that PUFA may have on breast cancer cell proliferation, apoptosis, migration, and invasion. While most of the results obtained with docosahexaenoic acid and/or eicosapentaenoic acid show a decrease of tumor cell proliferation and/or aggressivity, there is some evidence that other lipids, which accumulate in breast cancer tissues, such as arachidonic acid may have opposite effects. Finally, lipids and especially PUFAs appear as potential adjuvants to conventional cancer therapy.

Docosahexaenoic acid: a natural powerful adjuvant that improves efficacy for anticancer treatment with no adverse effects

Epidemiological studies have linked fish oil consumption to a decreased incidence of cancer. The anticancer effects of fish oil are mostly attributed to its content of omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, DHA, because of its unique effect of altering membrane composition, is often regarded as the major omega-3 fatty acid involved in anticancer activity. Although use of DHA as an anticancer drug to prevent or treat human cancer in clinical settings has not yet been well established, recent studies suggest that DHA can be very effective as an adjuvant with other anticancer agents. In this article, we present studies that show the role of DHA in improving anticancer drug efficacy. Several in vitro and animal studies suggest that combining DHA with other anticancer agents often improves efficacy of anticancer drugs and also reduces therapy-associated side effects. Incorporation of DHA in cellular membranes improves drug uptake, whereas increased lipid peroxidation is another mechanism for DHA-mediated enhanced efficacy of anticancer drugs. In addition, several intracellular targets including cyclooxygenase-2, nuclear factor kappa B, peroxisome proliferator-activated receptor gamma, mitogen-activated protein kinase, AKT, and BCL-2/BAX are found to play an important role in DHA-mediated additive or synergistic interaction with anticancer drugs. The data suggest that DHA is a safe, natural compound that can greatly improve the anticancer properties of anticancer drugs. Use of DHA with anticancer treatments provides an avenue to therapeutic improvement that involves less risk or side effects for patients and reduced regulatory burden for implementation.

The association of fish consumption with bladder cancer risk: a meta-analysis

Background

The association between fish consumption and risk of bladder cancer has not been established yet. The results from epidemiological studies are inconsistent.

Methods

We conducted a meta-analysis of cohort and case-control studies on the relationship between fish intake and bladder cancer. We quantified associations with bladder cancer using meta-analysis of relative risk associated to the highest versus the lowest category of fish intake using random effect models. Heterogeneity among studies was examined using Q and I² statistics. Publication bias was assessed using the Begg's funnel plot.

Results

Five cohort and 9 case-control studies were eligible for inclusion. The combined relative risk showed that fish consumption was negatively, but not significantly, associated with a decreased risk of bladder cancer (relative risk, 0.86; 95% confidence interval, 0.61-1.12). In subgroup analyses, there was no evidence that study design, geographical region, case sample size, or exposure assessment substantially influenced the estimate of effects.

Conclusion

The overall current literature on fish consumption and the risk of bladder cancer suggested no association. Because of the limited number of studies, further well-designed prospective studies are needed to explore the effect of fish on bladder cancer.

A synergistic antiproliferation effect of curcumin and docosahexaenoic acid in SK-BR-3 breast cancer cells: unique signaling not explained by the effects of either compound alone

Background

Breast cancer is a collection of diseases in which molecular phenotypes can act as both indicators and mediators of therapeutic strategy. Therefore, candidate therapeutics must be assessed in the context of multiple cell lines with known molecular phenotypes. Docosahexaenoic acid (DHA) and curcumin (CCM) are dietary compounds known to antagonize breast cancer cell proliferation. We report that these compounds in combination exert a variable antiproliferative effect across multiple breast cell lines, which is synergistic in SK-BR-3 cells and triggers cell signaling events not predicted by the activity of either compound alone.

Methods

Dose response curves for CCM and DHA were generated for five breast cell lines. Effects of the DHA+ CCM combination on cell proliferation were evaluated using varying concentrations, at a fixed ratio, of CCM and DHA based on their individual ED₅₀. Detection of synergy was performed using nonlinear regression of a sigmoid dose response model and Combination Index approaches. Cell molecular network responses were investigated through whole genome microarray analysis of transcript level changes. Gene expression results were validated by RT-PCR, and western blot analysis was performed for potential signaling mediators. Cellular curcumin uptake, with and without DHA, was analyzed via flow cytometry and HPLC.

Results

CCM+DHA had an antiproliferative effect in SK-BR-3, MDA-MB-231, MDA-MB-361, MCF7 and MCF10AT cells. The effect was synergistic for SK-BR-3 (ER^- PR^- Her2⁺) relative to the two compounds individually. A whole genome microarray approach was used to investigate changes in gene expression for the synergistic effects of CCM+DHA in SK-BR-3 cells lines. CCM+DHA triggered transcript-level responses, in disease-relevant functional categories, that were largely non-overlapping with changes caused by CCM or DHA individually. Genes involved in cell cycle arrest, apoptosis, inhibition of metastasis, and cell adhesion were upregulated, whereas genes involved in cancer development and progression, metastasis, and cell cycle progression were downregulated. Cellular pools of PPARγ and phospho-p53 were increased by CCM+DHA relative to either compound alone. DHA enhanced cellular uptake of CCM in SK-BR-3 cells without significantly enhancing CCM uptake in other cell lines.

Conclusions

The combination of DHA and CCM is potentially a dietary supplemental treatment for some breast cancers, likely dependent upon molecular phenotype. DHA enhancement of cellular curcumin uptake is one potential mechanism for observed synergy in SK-BR-3 cells; however, transcriptomic data show that the antiproliferation synergy accompanies many signaling events unique to the combined presence of the two compounds.

Brain fatty acid-binding protein and omega-3/omega-6 fatty acids: mechanistic insight into malignant glioma cell migration

Malignant gliomas (MG) are highly infiltrative tumors that consistently recur despite aggressive treatment. Brain fatty acid-binding protein (FABP7), which binds docosahexaenoic acid (DHA) and arachidonic acid (AA), localizes to sites of tumor infiltration and is associated with a poor prognosis in MG. Manipulation of FABP7 expression in MG cell lines affects cell migration, suggesting a role for FABP7 in tumor infiltration and recurrence. Here, we show that DHA inhibits and AA stimulates migration in an FABP7-dependent manner in U87 MG cells. We demonstrate that DHA binds to and sequesters FABP7 to the nucleus, resulting in decreased cell migration. This anti-migratory effect is partially dependent on peroxisome proliferator-activated receptor γ, a DHA-activated transcription factor. Conversely, AA-bound FABP7 stimulates cell migration by activating cyclooxygenase-2 and reducing peroxisome proliferator-activated receptor γ levels. Our data provide mechanistic insight as to why FABP7 is associated with a poor prognosis in MG and suggest that relative levels of DHA and AA in the tumor environment can make a profound impact on tumor growth properties. We propose that FABP7 and its fatty acid ligands may be key therapeutic targets for controlling the dissemination of MG cells within the brain.

Docosahexaenoic acid induces apoptosis in MCF-7 cells in vitro and in vivo via reactive oxygen species formation and caspase 8 activation

Background

The present study sought to further investigate the in vitro and in vivo anticancer effects of a representative omega-3 fatty acid, docosahexaenoic acid (DHA), with a focus on assessing the induction of oxidative stress and apoptosis as an important mechanism for its anticancer actions.

Methodology/Principal Findings

In vitro studies showed that DHA strongly reduces the viability and DNA synthesis of MCF-7 human breast cancer cells in culture, and also promotes cell death via apoptosis. Mechanistically, accumulation of reactive oxygen species and activation of caspase 8 contribute critically to the induction of apoptotic cell death. Co-presence of antioxidants or selective inhibition or knockdown of caspase 8 each effectively abrogates the cytotoxic effect of DHA. Using athymic nude mice as an in vivo model, we found that feeding animals the 5% fish oil-supplemented diet for 6 weeks significantly reduces the growth of MCF-7 human breast cancer cells in vivo through inhibition of cancer cell proliferation as well as promotion of cell death. Using 3-nitrotyrosine as a parameter, we confirmed that the fish oil-supplemented diet significantly increases oxidative stress in tumor cells in vivo. Analysis of fatty acid content in plasma and tissues showed that feeding animals a 5% fish oil diet increases the levels of DHA and eicosapentaenoic acid in both normal and tumorous mammary tissues by 329% and 300%, respectively.

Conclusions/Significance

DHA can strongly induce apoptosis in human MCF-7 breast cancer cells both in vitro and in vivo. The induction of apoptosis in these cells is selectively mediated via caspase 8 activation. These observations call for further studies to assess the effectiveness of fish oil as a dietary supplement in the prevention and treatment of human breast cancer.

Identification of a dietary pattern characterized by high-fat food choices associated with increased risk of breast cancer: the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study

Epidemiological studies conducted thus far have mainly used a single-nutrient approach which may not be sufficient in detecting diet-cancer relationships. The aim of the study was to examine the association of a food pattern based on explained variations in fatty acid intake by means of reduced rank regression with breast cancer risk. Study participants were female subjects (n 15,351) of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study free of cancer at baseline and with complete dietary and outcome information followed for an average of 6.0 years. Among those, 137 incident cases of invasive breast cancer were identified. We identified a food pattern characterized by low consumption of bread, and fruit juices, and high consumption of processed meat, fish, butter and other animal fats, and margarine explaining >42 % of total variation in fatty acid intake (SFA, MUFA, n-3 PUFA, n-6 PUFA). Intake of all four fatty acid fractions was positively associated with the pattern score. Adherence to this food pattern adjusted for covariates was associated with a two-fold risk (hazard ratio 2.00; 95 % CI 1.30, 3.09) of breast cancer comparing extreme tertiles of the pattern score. There was no evidence of effect modification by menopausal status, overweight status and use of hormone replacement therapy, respectively. In conclusion, a food pattern characterized by high-fat food choices was significantly associated with increased risk of breast cancer. Given that the food pattern was high in all fatty acid fractions, we found evidence for total dietary fat rather than for specific fatty acids to be associated with breast cancer risk.

The influence of feeding linoleic, gamma-linolenic and docosahexaenoic acid rich oils on rat brain tumor fatty acids composition and fatty acid binding protein 7 mRNA expression

Background

Experimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo.

Methods

GLA oil (GLAO; 72% GLA), DHA oil (DHAO; 73% DHA) were fed to adult wistar rats (1 mL/rat/day) starting one week prior to C6 glioma cells implantation and continued for two weeks after implantation. Control group were fed same amount of high linoleic acid safflower oil (74–77% linoleic acid). Fatty acid composition of tumor samples was determined in a set of 8–12 animals in each group and serum fatty acid in 6 animals per each group. Gene expression of tumor fatty acid binding protein 7 (FABP7), epidermal growth factor receptor (EGFR), peroxisome proliferator activated receptor γ (PPAR-γ) and retinoid × receptor-α (RXR-α) were determined in a set of 18 animals per group.

Results

DHAO feeding increased EPA of brain tumors and decreased ratio of n-6/n-3 fatty acids. Serum levels of EPA were also increased in DHAO group. A similar trend in serum and tumor levels of DHA were observed in DHAO group but it did not achieve statistical significance. GLAO increased serum concentration of GLA but had no significant effect on tumor GLA or dihomo-gamma linolenic acid (DGLA) concentrations. Gene expression of FABP7 was up-regulated in tumors of DHAO group but no other significant effects were observed on EGFR, PPAR-γ or RXR-α expression, and expression of these genes in tumors of GLAO were not different from SFO group.

Conclusion

Dietary supplementation of DHA containing oil could be an effective way to increase levels of long chain n-3 fatty acids in brain tumors and this increase may be mediated partly by up-regulation of FABP7 expression.

Lignan-rich sesame seed negates the tumor-inhibitory effect of tamoxifen but maintains bone health in a postmenopausal athymic mouse model with estrogen-responsive breast tumors

OBJECTIVE

Flaxseed, the richest source of mammalian lignan precursors, enhances the tumor growth-inhibitory effect of tamoxifen while exerting no adverse effects on other estrogen-responsive tissues such as bone. Ingestion of sesame seed produces mammalian lignans comparable with flaxseed, but its anticancer potential is unknown. This study determined the interactive effects of sesame seed and tamoxifen on established MCF-7 tumor growth and bone health in ovariectomized athymic mice simulating a postmenopausal condition.

DESIGN

Mice with established MCF-7 tumors were treated for 8 weeks with (1) basal diet (negative control), (2) 10% sesame seed, (3) basal diet + tamoxifen implant, (4) 10% sesame seed + tamoxifen implant, or (5) basal diet + estrogen implant (positive control). Weekly palpable tumor size, final tumor weight, cell proliferation, and apoptosis were measured. Bone mineral content, bone mineral density, and biomechanical strength testing were performed on the femur and lumbar vertebrae.

RESULTS

Sesame seed induced regression of established tumor size similar to the negative control but tended to negate the tumor-inhibitory effect of tamoxifen, in part by reducing apoptosis. Sesame seed combined with tamoxifen induced higher bone mineral content, bone mineral density, and biomechanical strength in the femur and lumbar vertebrae than either treatment alone. A significant positive relationship was found between final tumor weight and bone strength parameters.

CONCLUSIONS

Sesame seed is not protective and negatively interferes with tamoxifen in inducing regression of established MCF-7 tumor size but beneficially interacts with tamoxifen on bone in ovariectomized athymic mice.

Docosahexaenoic Acid (DHA), a Primary Tumor Suppressive Omega-3 Fatty Acid, Inhibits Growth of Colorectal Cancer Independent of p53 Mutational Status

Human colon carcinoma COLO 205, carrying wild type p53, grown subcutaneously in athymic mice was inhibited 80% by a high fat menhaden oil diet containing a mixture of omega-3 fatty acids compared to the low fat corn oil diet containing omega-6 fatty acids. Feeding a high fat diet of golden algae oil containing docosahexaenoic acid (DHA) as the sole long chain omega-3 fatty acid resulted in 93% growth inhibition. Similar findings were previously reported for WiDr colon carcinoma containing mutated p53 (His237). In vitro, 125 muM DHA inhibited COLO 205 growth by 81%, WiDr by 42%, while eicosapentaenoic acid (EPA) marginally inhibited growth of both lines by approximately 30%. DHA inhibited cell proliferation by 41% in WiDr but did not significantly inhibit proliferation in COLO 205. Cell cycle analysis revealed that DHA arrested cell cycle at Resting/Gap 1 (G0/G1 phase) in WiDr and at Gap 2/Mitosis (G2/M) phase in COLO 205. DHA induced apoptosis in COLO 205 but not in WiDr, and EPA did not induce apoptosis in either line. Taken together, these findings suggest DHA is the primary tumor suppressive omega-3 fatty acid in vivo and in vitro and inhibits cancer growth by p53 dependent and independent pathways, while the marginal inhibition by EPA is p53 independent.

Docosahexaenoic acid inhibits adipocyte differentiation and induces apoptosis in 3T3-L1 preadipocytes

Docosahexaenoic acid (DHA, C22:6), a (n-3) fatty acid in fish oil, has been shown to decrease body fat and fat accumulation in rodents. We investigated the direct effect of DHA on cell growth, differentiation, apoptosis, and lipolysis using 3T3-L1 adipocytes. Cells were treated with 25-200 mumol/L DHA containing 0.2 mmol/L alpha-tocopherol or bovine serum albumin vehicle as a control. Proliferation of preconfluent preadipocytes was not affected by the DHA treatment. When added to postconfluent preadipocytes, all concentrations of DHA inhibited differentiation-associated mitotic clonal expansion (P < 0.01). Postconfluent preadipocytes demonstrated apoptosis after 48 h with 100 mumol/L DHA and after 24 and 48 h with 200 mumol/L DHA (P < 0.01). Differentiation was examined by Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) activity after DHA treatment for 6 d. DHA decreased mean droplet size and percent lipid area in a dose-dependent manner (P < 0.01). GPDH activity was also decreased by DHA treatment (P < 0.01). In fully differentiated adipocytes, DHA increased basal lipolysis compared with the control (P < 0.01). These results demonstrate that DHA may exert its antiobesity effect by inhibiting differentiation to adipocytes, inducing apoptosis in postconfluent preadipocytes and promoting lipolysis.

n-3 polyunsaturated fatty acids endogenously synthesized in fat-1 mice are enriched in the mammary gland

In this study, we determined the phospholipid FA composition in the mammary gland of the transgenic Fat-1 mouse. This is the first animal model developed that can endogenously synthesize n-3 PUFA. The synthesis of n-3 PUFA is achieved through the expression of the fat-1 transgene encoding for an n-3 desaturase from Caenorhabditis elegans, which utilizes n-6 PUFA as substrate. Wild-type and Fat-1 female mice were terminated at 7 wk of age and the fifth mammary gland was removed. Lipids were extracted and phospholipids were separated by TLC and converted to FAME for analysis by GC. There was no significant change in total saturated, monounsaturated, and PUFA composition. However, there was a significant increase in total n-3 PUFA and a corresponding decrease in n-6 PUFA. The major n-3 PUFA that were enriched included 20:5n-3 and 22:6n-3. The n-6 PUFA that were reduced included 20:4n-6, 22:4n-6, and 22:5n-6. Overall, these findings demonstrate that female Fat-i mice have elevated levels of n-3 PUFA in the mammary gland. Moreover, the n-3 desaturase products are the same n-3 PUFA found in fish oil, which have been shown to have chemoprotective properties against breast cancer. Therefore, this newly developed mouse model may be highly useful for investigating molecular and cellular mechanisms by which n-3 PUFA prevents and inhibits breast cancer growth.

Docosahexaenoic acid (omega−3) blocks voltage-gated sodium channel activity and migration of MDA-MB-231 human breast cancer cells

Omega-3 polyunsaturated fatty acids have been suggested to play an important role in cancer prevention/progression, on the one hand, and in modulation of membrane ion channels on the other. We investigated whether docosahexaenoic acid would influence the in vitro migration of MDA-MB-231 human breast cancer cells. An important follow-up question was whether any effect would involve voltage-gated Na(+) channels, shown previously to occur in human breast cancer in vitro and in vivo and to correlate with metastatic potential. Short-term (acute) and long-term (24-72 h) application of docosahexaenoic acid suppressed the activity of the channel activity in a dose-dependent manner. At the working concentrations of docosahexaenoic acid used (0.05-0.5 microM), there was no effect on proliferation. Long-term treatment with docosahexaenoic acid down-regulated mRNA and protein (total and plasma membrane) levels of neonatal Nav1.5 voltage-gated Na(+) channel, known to be predominant in these cells. Docosahexaenoic acid suppressed migration of the MDA-MB-231 cells to the same extent as tetrodotoxin, a highly specific blocker of voltage-gated Na(+) channels, but the two effects were not additive. It was concluded that the docosahexaenoic acid-induced suppression of cellular migration occurred primarily via down-regulation of voltage-gated Na(+) channel (neonatal Nav1.5) mRNA and functional protein expression.

Mechanisms of omega-3 fatty acid-induced growth inhibition in MDA-MB-231 human breast cancer cells

The omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), inhibit the growth of human breast cancer cells in animal models and cell lines, but the mechanism by which this occurs is not well understood. In order to explore possible mechanisms for the modulation of breast cancer cell growth by omega-3 fatty acids, we examined the effects of EPA and DHA on the human breast cancer cell line MDA-MB-231. Omega-3 fatty acids (a combination of EPA and DHA) inhibited the growth of MDA-MB-231 cells by 30-40% (p<0.05) in both the presence and absence of linoleic acid, an essential omega-6 fatty acid. When provided individually, DHA was more potent than EPA in inhibiting the growth of MDA-MB-231 cells (p<0.05). EPA and DHA treatment decreased tumor cell proliferation (p<0.05), as estimated by decreased [methyl-(3)H]-thymidine uptake and expression of proliferation-associated proteins (proliferating cell nuclear antigen, PCNA, and proliferation-related kinase, PRK). In addition, EPA and DHA induced apoptosis, as indicated by a loss of mitochondrial membrane potential, increased caspase activity and increased DNA fragmentation (p<0.05). Cells incubated with omega-3 fatty acids demonstrated decreased Akt phosphorylation, as well as NFkappaB DNA binding activity (p<0.05). The results of this study indicate that omega-3 fatty acids decrease cell proliferation and induce apoptotic cell death in human breast cancer cells, possibly by decreasing signal transduction through the Akt/NFkappaB cell survival pathway.

Nutritional Intervention With Omega-3 Fatty Acids in a Case of Malignant Fibrous Histiocytoma of the Lungs

We present a case of a 78-yr-old man with malignant fibrous histiocytoma with multiple lesions in both lungs. Following diagnosis, he declined conventional chemotherapy and elected nutritional intervention by increasing intake of omega-3 fatty acids and lowering intake of omega-6 fatty acids. We estimated that he consumed 15 g of the long-chain omega-3 fatty acids eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) per day, and the ratio of linoleic acid/long-chain omega-3 fatty acids in his diet was 0.81. Serial computed tomography scans and pulmonary x-rays revealed remarkably a slow and steady decrease in the size and number of bilateral nodules. He has no apparent side effects from consuming large quantities of fish and algae oils rich in DHA and EPA and he remains asymptomatic.

Omega-3 Fatty Acids and the Regulation of Expression of Endothelial Pro-Atherogenic and Pro-Inflammatory Genes

By partially replacing the corresponding omega-6 analogues in membrane phospholipids, omega-3 fatty acids have been shown to decrease the transcriptional activation of genes--e.g., adhesion molecules, chemoattractants, inflammatory cytokines--involved in endothelial activation in response to inflammatory and pro-atherogenic stimuli. This regulation occurs, at least in part, through a decreased activation of the nuclear factor-kappaB system of transcription factors, secondary to decreased generation of intracellular hydrogen peroxide. Such regulation by omega-3 fatty acids is likely linked to the presence of a higher number of double bonds in the fatty acid chain in omega-3 compared with omega-6 fatty acids. By similar mechanisms, omega-3 fatty acids have been recently shown to reduce gene expression of cyclooxygenase-2, an inflammatory gene involved, through the activation of some metalloproteinases, in plaque angiogenesis and plaque rupture. The quenching of gene expression of pro-inflammatory pro-atherogenic genes by omega-3 fatty acids has consequences on the extent of leukocyte adhesion to vascular endothelium, early atherogenesis and later stages of plaque development and plaque rupture, ultimately yielding a plausible comprehensive explanation for the vasculoprotective effects of these nutrients.

Anticancer properties of propofol-docosahexaenoate and propofol-eicosapentaenoate on breast cancer cells

Introduction

Epidemiological evidence strongly links fish oil, which is rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), with low incidences of several types of cancer. The inhibitory effects of omega-3 polyunsaturated fatty acids on cancer development and progression are supported by studies with cultured cells and animal models. Propofol (2,6-diisopropylphenol) is the most extensively used general anesthetic–sedative agent employed today and is nontoxic to humans at high levels (50 μg/ml). Clinically relevant concentrations of propofol (3 to 8 μg/ml; 20 to 50 μM) have also been reported to have anticancer activities. The present study describes the synthesis, purification, characterization and evaluation of two novel anticancer conjugates, propofol-docosahexaenoate (propofol-DHA) and propofol-eicosapentaenoate (propofol-EPA).

Methods

The conjugates linking an omega-3 fatty acid, either DHA or EPA, with propofol were synthesized and tested for their effects on migration, adhesion and apoptosis on MDA-MB-231 breast cancer cells.

Results

At low concentrations (25 μM), DHA, EPA or propofol alone or in combination had minimal effect on cell adhesion to vitronectin, cell migration against serum and the induction of apoptosis (only 5 to 15% of the cells became apoptotic). In contrast, the propofol-DHA or propofol-EPA conjugates significantly inhibited cell adhesion (15 to 30%) and migration (about 50%) and induced apoptosis (about 40%) in breast cancer cells.

Conclusion

These results suggest that the novel propofol-DHA and propofol-EPA conjugates reported here may be useful for the treatment of breast cancer.

Omega-3 polyunsaturated fatty acids attenuate breast cancer growth through activation of a neutral sphingomyelinase-mediated pathway

The effect of fish oils and their active omega-3 fatty acid constituents, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), were investigated on breast cancer growth. In in vivo experiments, mice were fed diets that were rich in either omega-3 (fish oil) or omega-6 (corn oil) fatty acids. Three weeks after implantation of MDA-MB-231 breast cancer cells, the tumor volume and weight were significantly lower (p < 0.05) for mice fed the omega-3 diets compared to those fed the omega-6 diets. Dietary fish oil also caused a 40% (p < 0.05) increase in neutral sphingomyelinase (N-SMYase) activity in the tumors. The tumor tissues from fish oil-fed animals expressed elevated p21 (waf1/cip1) mRNA, whereas tumor tissues from corn oil-fed animals exhibited undetectable levels of p21 expression. In in vitro experiments, at concentrations as low as 25 muM, DHA and EPA inhibited the growth of cultured MDA-MB-231 cells in a dose-dependent manner by 20-25% (p < 0.05). N-SMYase activity was also increased by 30-40% (p < 0.05) in the DHA- or EPA-treated cells in which an increase in ceramide formation was observed. DHA and EPA were both observed to enhance membrane bleb formation and also to induce the expression of p21. Omega-3 fatty acids-induced bleb formation and p21 expression were inhibited by the N-SMYase inhibitor GW4869, which also inhibited apoptosis by approximately 40% (p < 0.05). The results suggest that inhibition of breast cancer growth in nude mice by dietary fish oil and inhibition of breast cancer cell growth in culture by treatment with DHA and EPA is mediated by activation of N-SMYase.

Docosahexaenoic acid induces apoptosis in proliferating human endothelial cells

n-3 polyunsaturated fatty acids (PUFAs) have been shown to exert beneficial effects in the prevention of cardiovascular disease, inflammation, and on tumor growth. To investigate effects of PUFAs on proliferation and apoptosis in endothelial cells, we tested the n-3 PUFA docosahexaenoic acid (DHA) and the n-6 PUFA arachidonic acid (AA) in human umbilical vein endothelial cells (HUVEC). The mitochondrial membrane potential (MMP) and the production of reactive oxygen species were examined by flow cytometry. Phosphorylation of p53 or p38 MAP kinase, and total levels of p53 were measured by Western blot. DNA binding activity of p53 was analyzed with a TransAM transcription factor assay kit. Tube formation was assessed on Matrigel. In proliferating HUVEC, but not in confluent cells, DHA reduced cell viability and induced apoptosis, as demonstrated by increases in membrane leakage (propidium iodide (PI) staining), Annexin-V binding, sub G(1) phase in the cell cycle, and TUNEL-positive cells. AA had no effect on these parameters. In addition to a reduced MMP and increased reactive oxygen species, phosphorylation of p38 and p53 (serine 15) and impaired DNA binding of p53 were observed. There was no change in total levels of p53. The p38 inhibitor SB203580 had no effect on Annexin V binding. DHA also attenuated HUVEC tube formation. Taken together, DHA induces apoptosis in proliferating, but not in resting HUVEC, potentially via the phosphorylation of p53, resulting in decreased p53 DNA binding. The results suggest that anti-angiogenic effects of DHA may be due to induction of apoptosis in proliferating endothelial cells.

Dietary factors modifying breast cancer risk and relation to time of intake

Multiple factors contribute to the development of human breast cancer. However, environmental factors, especially dietary factors, appear to have the greatest effects. Evidence obtained in epidemiological studies has been corroborated by laboratory findings. Dietary components strongly associated with breast cancer include fat and phytochemicals. A diet high in n-3 polyunsaturated fatty acid (PUFA) or monounsaturated fatty acid (MUFA) and low in n-6 PUFA is protective against breast cancer. Some phytochemicals present in fruits and vegetables are also protective. Time of intake appears to be important: lifetime protection may be achieved if one is exposed to a dietary factor that lowers breast cancer risk early in life. Synergistic and antisynergistic interactions between dietary factors can modify breast cancer risk. The available evidence suggests that breast cancer risk can be reduced by early dietary intervention.

(n-3) fatty acids and cancer therapy

Supplementing the diet of tumor-bearing mice or rats with oils containing (n-3) (omega-3) or with purified (n-3) fatty acids has slowed the growth of various types of cancers, including lung, colon, mammary, and prostate. The efficacy of cancer chemotherapy drugs such as doxorubicin, epirubicin, CPT-11, 5-fluorouracil, and tamoxifen, and of radiation therapy has been improved when the diet included (n-3) fatty acids. Some potential mechanisms for the activity of (n-3) fatty acids against cancer include modulation of eicosanoid production and inflammation, angiogenesis, proliferation, susceptibility for apoptosis, and estrogen signaling. In humans, (n-3) fatty acids have also been used to suppress cancer-associated cachexia and to improve the quality of life. In one study, the response to chemotherapy therapy was better in breast cancer patients with higher levels of (n-3) fatty acids in adipose tissue [indicating past consumption of (n-3) fatty acids] than in patients with lower levels of (n-3) fatty acids. Thus, in combination with standard treatments, supplementing the diet with (n-3) fatty acids may be a nontoxic means to improve cancer treatment outcomes and may slow or prevent recurrence of cancer. Used alone, an (n-3) supplement may be a useful alternative therapy for patients who are not candidates for standard toxic cancer therapies.

Biomarkers of dietary fatty acid intake and the risk of breast cancer: a meta-analysis

The use of the fatty acid composition of adipose tissue, erythrocyte membranes, serum and plasma as biological markers of fatty acid intake was recently introduced in epidemiological studies. The biomarkers of fatty acid intake have the advantage of providing quantitative measurement independent of energy intake and of the subject's memory. We performed a meta-analysis of published results of epidemiological studies of the composition of fatty acids in biological samples and breast cancer risk. The analysis was based on 3 cohort and 7 case-control studies including 2,031 cases and 2,334 controls. The summary statistic used was the average of the relative risk estimated for each level of the fatty acid on study, weighted by the inverse of its variance. Random effect models were assumed when the test for heterogeneity was significant. Overall relative risks were estimated for studies including pre- and post-menopausal breast cancer and separately for post-menopausal women. In cohort studies, a significant protective effect was found for total n-3 polyunsaturated fatty acids, while total monounsaturated fatty acids, oleic acid (C18:1 n-9c) and palmitic acid (C16:0) were significantly associated with an increase of breast cancer risk. Total saturated fatty acids were significantly associated with breast cancer risk in cohort studies only in postmenopausal women. For case-control studies, the only finding was for alpha linolenic acid (C18:3, n-3), which showed an inverse association bordering on statistical significance. The findings of cohort studies fit well with hypotheses derived from experimental animal studies. More epidemiological cohort studies that integrate biological markers of dietary fatty acid intake are needed in order to determine the contribution of different types of fatty acids in the etiology of breast cancer.

The traditional diet of Greece and cancer

The term 'Mediterranean diet', implying that all Mediterranean people have the same diet, is a misnomer. The countries around the Mediterranean basin have different diets, religions and cultures. Their diets differ in the amount of total fat, olive oil, type of meat, wine, milk, cheese, fruits and vegetables; and the rates of coronary heart disease and cancer, with the lower death rates and longer life expectancy occurring in Greece. The diet of Crete represents the traditional diet of Greece prior to 1960. Analyses of the dietary pattern of the diet of Crete shows a number of protective substances, such as selenium, glutathione, a balanced ratio of n-6/n-3 essential fatty acids (EFA), high amounts of fibre, antioxidants (especially resveratrol from wine and polyphenols from olive oil), vitamins E and C, some of which have been shown to be associated with lower risk of cancer, including cancer of the breast. Epidemiological studies and animal experiments indicate that n-3 fatty acids exert protective effects against some common cancers, especially cancers of the breast, colon and prostate. Many mechanisms are involved, including suppression of neoplastic transformation, cell growth inhibition, and enhanced apoptosis and anti-angiogenicity, through the inhibition of eicosanoid production from n-6 fatty acids; and suppression of cyclooxygenase 2 (COX-2), interleukin 1 (IL-1) and IL-6 gene expression by n-3 fatty acids. Recent intervention studies in breast cancer patients indicate that n-3 fatty acids, and docosahexaenoic acid (DHA) in particular, increase the response to chemopreventive agents. In patients with colorectal cancer, eicosapentaenoic acid (EPA) and DHA decrease cell proliferation, and modulate favourably the balance between colonic cell proliferation and apoptosis. These findings should serve as a strong incentive for the initiation of intervention trials that will test the effect of specific dietary patterns in the prevention and management of patients with cancer.

Evidence for potential mechanisms for the effect of conjugated linoleic acid on tumor metabolism and immune function: lessons from n-3 fatty acids

Conjugated linoleic acid (CLA) and the long-chain polyunsaturated n-3 fatty acids have been shown in vivo and in vitro to reduce tumor growth. Tumor growth could occur by slowing or stopping cell replication (by interfering with transition through the cell cycle), increasing cell death (via necrosis and/or apoptosis), or both. The anticancer effects of fatty acids, shown in vivo, could also be mediated by effects on the host's immune system. Although it is widely recognized that n-3 fatty acids can alter immune and inflammatory responses, considerably less is known about CLA. For n-3 fatty acids, several candidate mechanisms have been proposed for their immune effects, including changes in 1) membrane structure and composition, 2) membrane-mediated functions and signals (eg, proteins, eicosanoids), 3) gene expression, and 4) immune development. Considerable work has been done that shows the potential importance of CLA as an anticancer treatment; however, many questions remain as to how this effect occurs. This review summarizes the CLA and cancer literature and then uses the evidence for the anticancer immune and tumor properties of the long-chain n-3 fatty acids docosahexaenoic and eicosapentaenoic acids to suggest future research directions for mechanistic studies on CLA and cancer.

Conjugated docosahexaenoic acid suppresses KPL-1 human breast cancer cell growth in vitro and in vivo: potential mechanisms of action

Introduction

The present study was conducted to examine the effect of conjugated docosahexaenoic acid (CDHA) on cell growth, cell cycle progression, mode of cell death, and expression of cell cycle regulatory and/or apoptosis-related proteins in KPL-1 human breast cancer cell line. This effect of CDHA was compared with that of docosahexaenoic acid (DHA).

Methods

KPL-1 cell growth was assessed by colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay; cell cycle progression and mode of cell death were examined by flow cytometry; and levels of expression of p53, p21^Cip1/Waf1, cyclin D₁, Bax, and Bcl-2 proteins were examined by Western blotting analysis. In vivo tumor growth was examined by injecting KPL-1 cells subcutaneously into the area of the right thoracic mammary fat pad of female athymic mice fed a CDHA diet.

Results

CDHA inhibited KPL-1 cells more effectively than did DHA (50% inhibitory concentration for 72 hours: 97 μmol/l and 270 μmol/l, respectively). With both CDHA and DHA growth inhibition was due to apoptosis, as indicated by the appearance of a sub-G₁ fraction. The apoptosis cascade involved downregulation of Bcl-2 protein; Bax expression was unchanged. Cell cycle progression was due to G₀/G₁ arrest, which involved increased expression of p53 and p21^Cip1/Waf1, and decreased expression of cyclin D₁. CDHA modulated cell cycle regulatory proteins and apoptosis-related proteins in a manner similar to that of parent DHA. In the athymic mouse system 1.0% dietary CDHA, but not 0.2%, significantly suppressed growth of KPL-1 tumor cells; CDHA tended to decrease regional lymph node metastasis in a dose dependent manner.

Conclusion

CDHA inhibited growth of KPL-1 human breast cancer cells in vitro more effectively than did DHA. The mechanisms of action involved modulation of apoptosis cascade and cell cycle progression. Dietary CDHA at 1.0% suppressed KPL-1 cell growth in the athymic mouse system.

An enriched mixture of trans-10,cis-12-CLA inhibits linoleic acid metabolism and PGE2 synthesis in MDA-MB-231 cells

Conjugated linoleic acid (CLA) isomers are potent inhibitors of mammary tumor cell growth. Evidence suggests that CLA modulates essential fatty acid (EFA) metabolism; however, it is not clear which parts of this pathway are important regulatory points modulated by CLA. Enriched mixtures of D9-cis,11-trans (D9c,11t)- and D10-trans,12-cis (D10t,12c)-18:2 were used to assess outcome measures of EFA metabolism pertaining to membrane phospholipid incorporation, tumor cell growth, and prostaglandin E2 (PGE2) synthesis in the MDA-MB-231 mammary tumor cell line. Tumor cells were treated with linoleic acid (LA), an equal mixture (Mix), or enriched preparations of D9c,11t- or D10t,12c-18:2. Treatment with Mix or the enriched mixture of D10t,12c-18:2 significantly inhibited the synthesis of arachidonic acid (AA) from LA, resulting in increased levels of LA and decreased levels of AA in membrane phosphatidylcholine and phosphatidylethanolamine (P < 0.05). LA and AA levels were not altered in cells treated with enriched D9c,11t-18:2 and were similar to those in LA control treated cells. All CLA treatments reduced [3H]thymidine uptake, an indicator of tumor cell growth, by more than one-half relative to LA controls. MDA-MB-231 cells challenged with AA in the presence of all CLA mixtures resulted in significantly reduced PGE2 synthesis relative to controls treated with LA (P < 0.05). It is evident that individual isomers exert inhibitory effects at specific steps of EFA metabolism, which correspondingly leads to a reduction in PGE2 synthesis and, ultimately, tumor growth.

Dietary docosahexaenoic acid levels influence the outcome of arabinosylcytosine chemotherapy in L1210 leukemic mice

The purpose of this study was to investigate whether dietary supplementation with the n-3 fatty acid docosahexaenoic acid (DHA) in combination with arabinosylcytosine (AraC) chemotherapy could prolong the life expectancy of mice bearing L1210 leukemia. The four control diets included rodent chow, a diet containing 5% of a blended oil mimicking the fatty acid composition of rodent chow, and diets containing 5% or 10% fat with safflower oil as the main oil source. The two DHA-supplemented diets provided 1.5% or 3.5% DHA and 5% or 10% total fat, respectively. After tumor cell inoculation, mice were treated with AraC for 10 days. Mice fed the 5% safflower oil diet (30.1 -/+ 4.1 days), but not those fed the 10% safflower oil diet, survived longer than the chow-fed animals (22.1 -/+ 3.1 days, P = 0.05). The 1.5%-/+ DHA diet (average intake 1.8 g DHA/kg/day) was associated with a longer life span (33.3 -/+ 3.4 days, P < 0.01 vs. chow-fed) and no incidence of death due to drug toxicity. Further increasing DHA intake (4.5 g DHA/kg/day) resulted in shortened survival time (26.5 -/+ 2.0 days), increased circulating tumor cell burden, and lowered red blood cell concentrations. These data suggest that a modest level of dietary DHA or linoleic acid supplementation may improve the antineoplastic efficacy of AraC. However, overconsumption of DHA reverses the beneficial effect of DHA intake on drug sensitivity.