Dietary fat and breast cancer

Bovine holo-lactoferrin inhibits migration and invasion in MDA-MB-231 breast cancer cells

PURPOSE

Breast cancer is the most common malignancy in developed countries and the main cause of deaths in women worldwide. Lactoferrin (Lf) is an iron-binding protein constituted for a single polypeptide chain that is folded into two symmetrical lobes that bind Fe²⁺ or Fe³⁺. Lf has the ability to reversibly bind Fe³⁺ and is found free of Fe³⁺ (Apo-Lf) or associated with Fe³⁺ (Holo-Lf) with a different three-dimensional conformation. However, the role of bovine Apo-Lf (Apo-BLf) and bovine Holo-Lf (Holo-BLf) in the migration and invasion induced by linoleic acid (LA) and fetal bovine serum (FBS), as well as in the expression of mesenchymal and epithelial proteins in breast cancer cells has not been studied.

METHODS AND RESULTS

Scratch wound assays demonstrated that Holo-BLf and Apo-BLf do not induce migration, however they differentially inhibit the migration induced by FBS and LA in breast cancer cells MDA-MB-231. Western blot, invasion, zymography and immunofluorescence confocal microscopy assays demonstrated that Holo-BLf partly inhibit the invasion, FAK phosphorylation at tyrosine (Tyr)-397 and MMP-9 secretion, whereas it increased the number and size of focal adhesions induced by FBS in MDA-MB-231 cells. Moreover, Holo-BLf induced a slight increase of E-cadherin expression in MCF-7 cells, and inhibited vimentin expression in MCF-7 and MDA-MB-231 breast cancer cells.

CONCLUSION

Holo-BLf inhibits cellular processes that mediate the invasion process in breast cancer cells.

Adipose-Derived Stem Cells from Fat Tissue of Breast Cancer Microenvironment Present Altered Adipogenic Differentiation Capabilities

Mesenchymal stem cells (MSCs) are multipotent cells able to differentiate into multiple cell types, including adipocytes, osteoblasts, and chondrocytes. The role of adipose-derived stem cells (ADSCs) in cancers is significantly relevant. They seem to be involved in the promotion of tumour development and progression and relapse processes. For this reason, investigating the effects of breast cancer microenvironment on ADSCs is of high importance in order to understand the relationship between tumour cells and the surrounding stromal cells. With the current study, we aimed to investigate the specific characteristics of human ADSCs isolated from the adipose tissue of breast tumour patients. We compared ADSCs obtained from periumbilical fat (PF) of controls with ADSCs obtained from adipose tissue of breast cancer- (BC-) bearing patients. We analysed the surface antigens and the adipogenic differentiation ability of both ADSC populations. C/EBPδ expression was increased in PF and BC ADSCs induced to differentiate compared to the control while PPARγ and FABP4 expressions were enhanced only in PF ADSCs. Conversely, adiponectin expression was reduced in PF-differentiated ADSCs while it was slightly increased in differentiated BC ADSCs. By means of Oil Red O staining, we further observed an impaired differentiation capability of BC ADSCs. To investigate this aspect more in depth, we evaluated the effect of selective PPARγ activation and nutritional supplementation on the differentiation efficiency of BC ADSCs, noting that it was only with a strong differentiation stimuli that the process took place. Furthermore, we observed no response in BC ADSCs to the PPARγ inhibitor T0070907, showing an impaired activation of this receptor in adipose cells surrounding the breast cancer microenvironment. In conclusion, our study shows an impaired adipogenic differentiation capability in BC ADSCs. This suggests that the tumour microenvironment plays a key role in the modulation of the adipose microenvironment located in the surrounding tissue.

Association between Cyclin D1 G870A (rs9344) polymorphism and cancer risk in Indian population: meta-analysis and trial sequential analysis

Introduction: Association between Cyclin D1 (CCND1) single nucleotide polymorphism (SNP) rs9344 and cancer risk is paradoxical. Thus, we performed a meta-analysis to explore the association between CCND1 variant and overall cancer risk in Indian population. Methods: Data from 12 published studies including 3739 subjects were collected using Pubmed and Embase. RevMan (Review Manager) 5.3 was used to perform the meta-analysis. OR with 95%CI were calculated to establish the association. Results: Overall, the cumulative findings demonstrated that CCND1 polymorphism (rs9344) was not significantly associated with cancer risk in all the genetic models studied (dominant model: GG vs GA+AA: OR (95%CI) = 0.81 (0.60-1.09), P=0.17; recessive model: GG+GA vs AA: OR (95%CI) = 1.23 (0.96-1.59), P=0.11; co-dominant model: GG vs AA: OR (95%CI) = 1.35 (0.93-1.97), P=0.12; co-dominant model: (GG vs GA: OR (95%CI) = 1.16 (0.85-1.59), P=0.34; allelic model: A vs G: OR (95%CI) = 1.20 (1.14-2.85), P=0.23; allelic model: G vs A: OR (95%CI) = 0.83 (0.62-1.12), P=0.23). Subgroup analysis according to cancer types presented significant association of CCND1 polymorphism and increased breast cancer risk in dominant model (GG vs GA+AA: OR = 2.75, 95%CI = 1.54-4.90, P=0.0006) and allelic model (G vs A: OR = 1.63, 95%CI = 1.22-2.19, P=0.001). An increased esophageal cancer risk in recessive model (GG+GA vs AA: OR = 1.51, 95%CI = 1.05-2.16, P=0.03) and co-dominant model (GG vs AA: OR = 2.51, 95%CI = 1.10-5.71, P=0.03) was detected. A higher risk for colorectal cancer was detected under both the co-dominant models (GG vs AA: OR = 2.46, 95%CI = 1.34-4.51, P=0.004 and GG vs GA: OR = 1.74, 95%CI = 1.14-2.67, P=0.01). However, in case of cervical cancer risk a non-significant association was reported under the recessive model (GG+GA vs AA: OR = 1.52, 95%CI = 0.60-3.90, P=0.38) with reference to CCND1 polymorphism (rs9344). The trial sequential analysis (TSA) showed that the cumulative Z-curve neither crossed the trial sequential monitoring boundary nor reached the required information size (RIS). Thus, present meta-analysis remained inconclusive due to insufficient evidence. Conclusion:CCND1 polymorphism rs9344 may not have a role in overall cancer susceptibility in Indian population. However, this polymorphism acts as a crucial risk factor for breast, esophageal, and colorectal cancer but not for cervical cancer. Future studies with larger sample size are required to draw a reliable conclusion.

Cow's Milk Consumption and Health: A Health Professional's Guide

The most recent scientific evidence supports the consumption of cow's milk and dairy products as part of a balanced diet. However, these days, the public and practicing physicans are exposed to a stream of inconsistent (and often misleading) information regarding the relationship between cow's milk intake and health in the lay press and in the media. The purpose of this article, in this context, is to facilitate doctor-patient communication on this topic, providing physicians with a series of structured answers to frequently asked patient questions. The answers range from milk and milk-derived products' nutritional function across the life span, to their relationship with diseases such as osteoporosis and cancer, to lactose intolerance and milk allergy, and have been prepared by a panel of experts from the Italian medical and nutritional scientific community. When consumed according to appropriate national guidelines, milk and its derivatives contribute essential micro- and macronutrients to the diet, especially in infancy and childhood where bone mass growth is in a critical phase. Furthermore, preliminary evidence suggests potentially protective effects of milk against overweight, obesity, diabetes, and cardiovascular disease, while no clear data suggest a significant association between milk intake and cancer. Overall, current scientific literature suggests that an appropriate consumption of milk and its derivatives, according to available nutritional guidelines, may be beneficial across all age groups, with the exception of specific medical conditions such as lactose intolerance or milk protein allergy. Key teaching points: Milk and its derivatives contribute essential micro and macronutrients to the diet, when consumed according to appropriate national guidelines, especially in infancy and childhood where bone mass growth is in a critical phase. Preliminary evidence suggests potentially protective effects of milk against overweight, obesity, diabetes and cardiovascular disease No clear data are available about the association between milk intake and cancer. Current scientific literature suggests that an appropriate consumption of milk and its derivatives may be beneficial at all ages, with the exception of specific medical conditions such as lactose intolerance or milk protein allergy.

Linoleic acid induces an increased response to insulin in MDA-MB-231 breast cancer cells

Epidemiological studies and animal models suggest a link between high levels of dietary fat intake and an increased risk of developing breast cancer. Hyperinsulinemia is a feature of obesity, diabetes, and metabolic syndrome that is associated with an increased breast cancer risk. Insulin is a hormone involved in metabolic regulation of carbohydrate. However, it is also a growth factor that mediates proliferation and migration. Linoleic acid (LA) is a fatty acid that induces migration and invasion in breast cancer cells. In the present study, we demonstrate, for the first time, that treatment with LA increases IR and IGF1R expression through a Free Fatty Acid Receptor 4 (FFAR4)-, lipooxygenases (LOXs)-, and SRC-dependent pathway in MDA-MB-231 breast cancer cells, and similarly induces an increase of IR expression in MCF-7 breast cancer cells. In addition, insulin induces tyrosine phosphorylation of IR/IGF1R and migration in MDA-MB-231 cells pretreated with LA, whereas it augments the increase in migration in MCF-7 cells pretreated with LA. Pretreatment of MDA-MB-231 cells with LA induces invasion, proliferation, and increase the MMP-9 secretion induced by insulin. In summary, our findings demonstrate that treatment with LA induces a higher response to insulin in breast cancer cells.

Prognostic Significance of Serum Vitamin D Levels in Egyptian Females with Breast Cancer

Objective:

To determine the frequency and prognostic significance of vitamin D deficiency in Egyptian women with breast cancer (BC).

Methods:

This prospective study included 50 women with primary invasive, non-metastatic BC. The serum level of 25-hydroxy vitamin D [25(OH)D was measured by ELISA at diagnosis, before any cancer treatment. Vitamin D deficiency was defined as 25(OH) D<20 ng/mL. Patients were followed up for a median of 30 months (range: 18-48).

Results:

The median level of 25(OH)D was 29.0 ng/mL (range: 10.0-55.0 ng/mL). Fifteen patients (30%) had vitamin D deficiency, which was positively associated with larger tumor size (p < 0.001), higher grade (p = 0.014), advanced stage (p = 0.001), lymph node positivity (p = 0.012), and HER2/neureceptor expression (p = 0.002). It was also linked with worse overall survival (OS) and disease free survival (DFS) (p = 0.026, and p = 0.004, respectively). On multivariate analysis, DFS was independently affected by vitamin D deficiency with an HR of 2.8 (95%CI: 1.6-7.0, p = 0.022) and advanced stage, i.e. stage II had worse survival compared to stage I with an HR of 4.8 (95%CI:1.1-21.7, p = 0.042).

Conclusion:

Vitamin D deficiency had a negative effect on overall and disease-free survival in our breast cancer cases, being related to tumor size, stage, grade, nodal status and HER2/neu receptor expression.

Migration and invasion induced by linoleic acid are mediated through fascin in MDA-MB-231 breast cancer cells

Epidemiological studies strongly suggest an association between high levels of dietary fat intake and an increased risk of developing breast cancer. Linoleic acid (LA) is an essential omega-6 PUFA and the major fatty acid in occidental diets. In breast cancer cells, LA induces expression of plasminogen activator inhibitor-1, proliferation, migration, and invasion. Fascin is an actin crosslinker globular protein that generates actin bundles made of parallel actin filaments, which mediate formation and stability of microspikes, stress fibers, membrane ruffles, and filopodia. However, the role of fascin in migration and invasion induced by LA in MDA-MB-231 breast cancer cells remains to be studied. We demonstrate here that LA induces an increase of fascin expression in MDA-MB-231 and MCF12A mammary epithelial cells. Particularly, LA induces the formation of filopodia and lamellipodia and the localization of fascin in these actin structures in MDA-MB-231 breast cancer cells. However, LA only induces formation of microspikes and the localization of fascin in these actin structures in mammary non-tumorigenic epithelial cells MCF12A. In addition, LA induces migration, invasion, and matrix metalloproteinase-9 secretion through a fascin-dependent pathway in MDA-MB-231 cells. In summary, our findings demonstrate that fascin is required for migration and invasion induced by LA in MDA-MB-231 breast cancer cells.

Association of CCND1 Gene c.870G>A Polymorphism with Breast Cancer Risk: A Case-ControlStudy and a Meta-Analysis

Cyclin D1 (CCND1) plays an essential role in regulating the progress of the cell cycle from G1 to S phase. There is a common c.870G>A polymorphism in the CCND1 gene. The aim of this study was to investigate the association of CCND1 gene c.870G>A polymorphism with breast cancer risk in a case-control study, which followed by a meta-analysis and an in silico analysis. Three hundred and thirty-five subjects composed of 174 women with breast cancer and 161 healthy controls were included in the case-control study. CCND1 gene c.870G>A genotyping was performed by PCR-RFLP. Meta-analysis was done for 14 studies composed of 7281 cases and 6820 controls. Some bioinformatics tools were applied to investigate the effects of c.870G>A on the mRNA splicing and structure. Our data obtained from case-control study revealed that GA genotype (OR: 1.89, 95%CI: 1.12-3.17, p = 0.017), AA genotype (OR: 1.95, 95%CI: 1.08-3.53, p = 0.027), and A allele (OR: 1.44, 95%CI: 1.06-1.95, p = 0.019) were significantly associated with breast cancer risk. The results of meta-analysis showed a significant association between CCND1 c.870G>A polymorphism and breast cancer risk, especially in Caucasian population. In silico analysis revealed that c.870G>A transition affect CCND1 mRNA splicing and secondary structure.

The role of background diet on the effects of eicosapentaenoic acid and docosahexaenoic acid supplementation in healthy pre-menopausal women: a randomized, cross-over, controlled study

Background

The links between dietary fat intake, polyunsaturated fatty acid intake and breast cancer risk remain equivocal, with some studies pointing to improvements in risk upon omega-3 supplementation. However, the background diet is poorly controlled in most studies, potentially confounding this link. Therefore, this study examined the hypothesis that in order to see the benefits of omega-3 fatty acid supplementation, the background diet must be low in fat.

Methods

Of the 56 healthy, pre-menopausal women randomized to one of two experimental arms, consisting of a two-treatment, randomized, cross-over design, 41 completed the 10 month intervention. The two diet phases (habitual and low-fat) were separated by a washout phase, each lasting 3 menstrual cycles. During each diet phase, women were supplemented with 1.2 g eicosapentaenoic acid + docosahexaenoic acid per day.

Results

Red blood cell fatty acid composition indicated that more eicosapentaenoic acid and docosahexaenoic acid was incorporated in the low-fat diet than the habitual diet, though both diet phases resulted in significant increases in the omega-3 to omega-6 ratio. In the context of omega-3 supplementation in breast cancer risk reduction, we also measured fatty acid incorporation into nipple aspirate fluid. Similar changes to red blood cells were noted in nipple aspirate fluid, with higher incorporation of eicosapentaenoic acid in the low-fat diet phase.

Conclusions

These data suggest that the total level of dietary fat has some direct impact on fatty acid partitioning in addition to the recognized importance of fatty acid ratios, and supports the hypothesis that dietary fat intake must be considered a confounder in supplementation trials. Additionally, we demonstrate that n3 supplementation both reaches and imparts improvements in lipid content and n3:n6 at the target breast tissue.

Trial registration

Trial was been retrospectively registered at clinicaltrials.gov (RegNCT02816125).

Different Biological Action of Oleic Acid in ALDHhigh and ALDHlow Subpopulations Separated from Ductal Carcinoma In Situ of Breast Cancer

The mechanisms underlying breast cancer progression of ductal carcinoma in situ (DCIS) associated with fatty acids are largely unknown. In the present study, we compared the action of oleic acid (OA) on two human DCIS cell lines, MCF10DCIS.COM (ER/PR/HER2-negative) and SUM225 (HER2 overexpressed). OA led to a significant increase in proliferation, migration, lipid accumulation and the expression of lipogenic proteins, such as SREBP-1, FAS and ACC-1, in MCF10DCIS.COM cells but not SUM225 cells. The ALDH^high subpopulation analyzed by the ALDEFLUOR assay was approximately 39.2±5.3% of MCF10DCIS.COM cells but was small (3.11±0.9%) in SUM225 cells. We further investigated the different biological action of OA in the distinct ALDH^low and ALDH^high subpopulations of MCF10DCIS.COM cells. OA led to an increase in the expression of ALDH1A1, ALDH1A2 and ALDH1A3 in MCF10DCIS.COM cells. SREBP-1 and ACC-1 were highly expressed in ALDH^high cells relative to ALDH^low cells, whereas FAS was higher in ALDH^low cells. In the presence of OA, ALDH^high cells were more likely to proliferate and migrate and displayed significantly high levels of SREBP-1 and FAS and strong phosphorylation of FAK and AKT relative to ALDH^low cells. This study suggests that OA could be a critical risk factor to promote the proliferation and migration of ALDH^high cells in DCIS, leading to breast cancer progression.

Extracellular vesicles from MDA-MB-231 breast cancer cells stimulated with linoleic acid promote an EMT-like process in MCF10A cells

Extracellular vesicles (EVs) are membrane-limited vesicles secreted by normal and malignant cells and their function is dependent on the cargo they carry and the cell type from which they originate. Moreover, EVs mediate many stages of tumor progression including angiogenesis, escape from immune surveillance and extracellular matrix degradation. Linoleic acid (LA) is an essential polyunsaturated fatty acid that induces expression of plasminogen activator inhibitor-1, proliferation, migration and invasion in breast cancer cells. However the role of secreted EVs from MDA-MB-231 cells stimulated with LA like mediator of the epithelial-mesenchymal-transition (EMT) process in mammary non-tumorigenic epithelial cells MCF10A remains to be studied. In the present study, we demonstrate that treatment of MDA-MB-231 cells for 48 h with 90 µM LA does not induce an increase in the number of secreted EVs. In addition, EVs isolated from supernatants of MDA-MB-231 stimulated for 48 h with 90 µM LA induce a transient down-regulation of E-cadherin expression, and an increase of Snail1 and 2, Twist1 and 2, Sip1, vimentin and N-cadherin expression in MCF10A cells. EVs also promote an increase of MMP-2 and -9 secretions, an increase of NFκB-DNA binding activity, migration and invasion in MCF10A cells. In summary, our findings demonstrate, for the first time, that EVs isolated from supernatants of MDA-MB-231 stimulated for 48 h with 90 µM LA induce an EMT-like process in MCF10A cells.

Arachidonic acid promotes migration and invasion through a PI3K/Akt-dependent pathway in MDA-MB-231 breast cancer cells

Arachidonic acid (AA) is a common dietary n-6 cis polyunsaturated fatty acid that under physiological conditions is present in an esterified form in cell membrane phospholipids, however it might be present in the extracellular microenvironment. AA and its metabolites mediate FAK activation, adhesion and migration in MDA-MB-231 breast cancer cells. However, it remains to be investigated whether AA promotes invasion and the signal transduction pathways involved in migration and invasion. Here, we demonstrate that AA induces Akt2 activation and invasion in MDA-MB-231 cells. Akt2 activation requires the activity of Src, EGFR, and PIK3, whereas migration and invasion require Akt, PI3K, EGFR and metalloproteinases activity. Moreover, AA also induces NFκB-DNA binding activity through a PI3K and Akt-dependent pathway. Our findings demonstrate, for the first time, that Akt/PI3K and EGFR pathways mediate migration and invasion induced by AA in MDA-MB-231 breast cancer cells.

Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence

Milk is a widely consumed beverage that is essential to the diet of several millions of people worldwide because it provides important macro- and micronutrients. Milk is recognized as being useful during childhood and adolescence because of its composition; however, its relatively high saturated fat proportion raises issues of potential detrimental effects, namely on the cardiovascular system. This review evaluates the most recent literature on dairy and human health, framed within epidemiologic, experimental, and biochemical evidence. As an example, the effects of milk (notably skimmed milk) on body weight appear to be well documented, and the conclusions of the vast majority of published studies indicate that dairy consumption does not increase cardiovascular risk or the incidence of some cancers. Even though the available evidence is not conclusive, some studies suggest that milk and its derivatives might actually be beneficial to some population segments. Although future studies will help elucidate the role of milk and dairy products in human health, their use within a balanced diet should be considered in the absence of clear contraindications.

Olive oil and other dietary lipids in breast cancer

Breast cancer is the most frequent malignant neoplasia among women worldwide. In addition to genetic and endocrine factors, the environment, and specifically nutritional factors, plays a key role in its aetiology. Epidemiological and in particular experimental studies have shown the link between dietary fat and breast cancer. Abundant data have attributed a potentially chemopreventive effect for extra-virgin olive oil (EVOO), the main source of fat in the Mediterranean diet, which is associated with low incidence and mortality rates from chronic diseases such as breast cancer. We have demonstrated the differential modulatory effect of dietary lipids on mammary carcinogenesis, mainly in studies developed in an experimental model. Thus, diets high in n-6 polyunsaturated fatty acids (PUFA) have a clear stimulating influence, whereas EVOO diets mainly have a negative modulatory effect on breast cancer development. The specific mechanisms involved are not fully understood, but nowadays, it is widely accepted that they are numerous and complex. Our group has contributed to improving the knowledge of these mechanisms by demonstrating the influence of dietary lipids on the structure and function of cell membranes, the modulation of cell-signalling transduction pathways, the regulation of gene expression and growth and sexual maturity.

Barriers and facilitators influencing the physical activity of Arabic adults: A literature review

Physical inactivity is a global health concern. Evidence suggests low levels of physical activity among Arabic adults living in Middle Eastern countries. To help ensure the success of strategies to promote physical activity, a better understanding of the barriers and facilitators to physical activity is needed. The objective of this article is to present a review of the literature that focuses on the barriers and facilitators to physical activity among Arabic adults. A socio-ecological framework was used to guide this review. Following a database search (2002–2013), a total of 15 studies were included in this review. The findings revealed that barriers (i.e., factors that impede physical activity), occurred at the individual level (e.g., lack of time, health status), social/cultural/policy level (e.g., traditional roles for women, lack of social support, use of housemaids), and the environmental level (e.g., hot weather, lack of exercise facilities). Some of the facilitators (i.e., factors that enable/promote physical activity) were: Muslim religion, desire to have slimmer bodies, and having good social support systems. Future intervention studies aimed at promoting physical activity among Arabic adults need to address these multiple influencing factors.

Principais alterações físico-químicas em óleos e gorduras submetidos ao processo de fritura por imersão: regulamentação e efeitos na saúde

Alimentos fritos são muito consumidos no Brasil e no mundo. Sabe-se que a fritura é um processo complexo e oferece riscos à saúde humana. Um dos objetivos desta revisão foi apresentar as principais alterações físicas (escurecimento, viscosidade e formação de espuma) e químicas (hidrólise e auto-oxidação) que ocorrem nos óleos e/ou gorduras durante o processo de fritura. Outro objetivo foi abordar os principais fatores envolvidos na degradação do óleo e/ou da gordura de fritura (temperatura e tempo de fritura; relação superfície/volume; tipo de aquecimento; tipo de óleo; adição de óleo novo; natureza e quantidade do alimento frito; presença de contaminantes metálicos e equipamento utilizado, além da presença de antioxidantes). Foram também apresentados alguns métodos de controle de qualidade de óleo ou de gordura de fritura existentes (quantificação de compostos polares totais, acidez, índice de peróxidos, valor de p-anisidina e métodos rápidos de quantificação). Por fim, foram relacionadas as regulamentações vigentes sobre o processo de fritura, os efeitos dos compostos degradados sobre a saúde humana e algumas recomendações para a melhoria da qualidade do óleo ou da gordura de fritura formuladas pelo Informe Técnico nº 11 da Agência Nacional de Vigilância Sanitária.

Polyunsaturated fatty acids affect the localization and signaling of PIP3/AKT in prostate cancer cells

AKT is a serine-threonine protein kinase that plays important roles in cell growth, proliferation and apoptosis. It is activated after binding to phosphatidylinositol phosphates (PIPs) with phosphate groups at positions 3,4 and 3,4,5 on the inositol ring. In spite of extensive research on AKT, one aspect has been largely overlooked, namely the role of the fatty acid chains on PIPs. PIPs are phospholipids composed of a glycerol backbone with fatty acids at the sn-1 and sn-2 position and inositol at the sn-3 position. Here, we show that polyunsaturated fatty acids (PUFAs) modify phospholipid content. Docosahexaenoic acid (DHA), an ω3 PUFA, can replace the fatty acid at the sn-2 position of the glycerol backbone, thereby changing the species of phospholipids. DHA also inhibits AKT(T308) but not AKT(S473) phosphorylation, alters PI(3,4,5)P3 (PIP3) and phospho-AKT(S473) protein localization, decreases pPDPK1(S241)-AKT and AKT-BAD interaction and suppresses prostate tumor growth. Our study highlights a potential novel mechanism of cancer inhibition by ω3 PUFA through alteration of PIP3 and AKT localization and affecting the AKT signaling pathway.

Arachidonic acid induces an increase of β-1,4-galactosyltransferase I expression in MDA-MB-231 breast cancer cells

Arachidonic acid (AA) is a common dietary n-6 cis polyunsaturated fatty acid that under physiological conditions is present in an esterified form in cell membrane phospholipids, and it might be present in the extracellular microenvironment. AA and its metabolites are implicated in FAK activation and cell migration in MDA-MB-231 breast cancer cells, and an epithelial-to-mesenchymal-like transition process in mammary non-tumorigenic epithelial cells MCF10A. During malignant transformation is present an altered expression of glycosiltransferases, which promote changes on the glycosilation of cell-surface proteins. The β-1,4-galactosyltransferase I (GalT I) is an enzyme that participates in a variety of biological functions including cell growth, migration, and spreading. However, the participation of AA in the regulation of GalT I expression and the role of this enzyme in the cell adhesion process in breast cancer cells remains to be investigated. In the present study, we demonstrate that AA induces an increase of GalT I expression through a PLA2α, Src, ERK1/2, and LOXs activities-dependent pathway in MDA-MB-231 breast cancer cells. Moreover, MDA-MB-231 cells adhere to laminin via GalT I expression and pretreatment of cells with AA induces an increase of cell adhesion to laminin. In conclusion, our findings demonstrate, for the first time, that AA promotes an increase of GalT I expression through an AA metabolism, Src and ERK1/2 activities-dependent pathway, and that GalT I plays a pivotal role in cell adhesion to laminin in MDA-MB-231 breast cancer cells.

Role of LOXs and COX-2 on FAK activation and cell migration induced by linoleic acid in MDA-MB-231 breast cancer cells

BACKGROUND

Epidemiological studies and animal models suggest a link between high levels of dietary fat intake and an increased risk of developing breast cancer. Particularly, free fatty acids (FFAs) are involved in several processes, including proliferation, migration and invasion, in breast cancer cells. Linoleic acid (LA) is a dietary n-6 polyunsaturated fatty acid that is known to induce proliferation and invasion in breast cancer cells. So far, however, the contribution of LA to focal adhesion kinase (FAK) activation and cell migration in breast cancer cells has not been studied.

RESULTS

Here, we show that LA promotes FAK and Src activation, as well as cell migration, in MDA-MB-231 breast cancer cells. FAK activation and cell migration require Src, Gi/Go, COX-2 and LOXs activities, whereas both are independent of Δ6 desaturase activity. In addition, we show that cell migration requires FAK activity, whereas FAK activation requires Src activity, thus suggesting a reciprocal catalytic activation mechanism of FAK and Src.

CONCLUSIONS

In summary, our findings show that LA induces FAK activation and cell migration in MDA-MB-231 breast cancer cells.

Linoleic acid induces an EMT-like process in mammary epithelial cells MCF10A

Epidemiological studies and animal models suggest an association between high levels of dietary fat intake and an increased risk of developing breast cancer. Epithelial-mesenchymal-transition (EMT) is a process, by which epithelial cells are transdifferentiated to a mesenchymal state, and it has been implicated in cancer progression, including invasion and metastasis. Linoleic acid (LA) induces proliferation and invasion in breast cancer cells. However, the role of LA on the EMT process in human mammary epithelial cells remains to be studied. In the present study, we demonstrate that LA induces a transient down-regulation of E-cadherin expression, accompanied with an increase of Snail1, Snail2, Twist1, Twist2 and Sip1 expressions. Furthermore, LA induces FAK and NFκB activation, MMP-2 and -9 secretions, migration and invasion. In summary, our findings demonstrate, for the first time, that LA promotes an EMT-like process in MCF10A human mammary epithelial cells.

Oleic acid promotes MMP-9 secretion and invasion in breast cancer cells

Epidemiological and animal studies suggest an association between dietary fatty acids and an increase risk of developing breast cancer. Obesity, which is characterized by hyperlipidemia and an elevation of circulating free fatty acids (FFAs), is also associated with enhanced cancer risk. In breast cancer cells, the FFA oleic acid (OA) induces migration, proliferation, prolong survival, invasion, an increase in cellular Ca(2+) concentration, MEK1/2, ERK1/2, FAK and Src activation. However, the role of OA on MMP-9 secretion and invasion has not been studied in detail. We demonstrate here that stimulation of MDA-MB-231 breast cancer cells with 200 μM OA induces an increase on MMP-9 secretion through a PKC, Src, and EGFR-dependent pathway, as revealed by gelatin zymography assays. Furthermore, microtubule network mediates MMP-9 secretion induced by OA. In contrast, OA does not induce an increase on MMP-9 secretion in MCF10A cells, whereas it does not induce MMP-9 secretion in MCF12A mammary non-tumorigenic epithelial cells. In addition, OA induces invasion through an EGFR, Gi/Go proteins, MMPs, PKC and Src-dependent pathway, but it is not able to promote invasion in non-invasive MCF-7 breast cancer cells. In summary, our findings demonstrate that OA promotes an increase on MMP-9 secretion and invasion through a PKC, Src, and EGFR-dependent pathway in breast cancer cells.

Arachidonic acid promotes epithelial-to-mesenchymal-like transition in mammary epithelial cells MCF10A

Epidemiological studies and animal models suggest an association between high levels of dietary fat intake and an increased risk of breast cancer. Cancer progression requires the development of metastasis, which is characterized by an increase in cell motility and invasion. Epithelial-to-mesenchymal transition (EMT) is a process, by which epithelial cells are transdifferentiated to a more mesenchymal state. A similar process takes place during tumor progression, when carcinoma cells stably or transiently lose epithelial polarities and acquire a mesenchymal phenotype. Arachidonic acid (AA) is a fatty acid that mediates cellular processes, such as cell survival, angiogenesis, chemotaxis, mitogenesis, migration and apoptosis. However, the role of AA on the EMT process in human mammary epithelial cells remains to be studied. We demonstrate here that AA promotes an increase in vimentin and N-cadherin expression, MMP-9 secretion, a decrease in E-cadherin junctional levels, and the activation of FAK, Src and NF-kappaB in MCF10A cells. Furthermore, AA also promotes cell migration in an Src kinase activity-dependent fashion. In conclusion, our results demonstrate, for the first time, that AA promotes an epithelial-to-mesenchymal-like transition in MCF10A human mammary non-tumorigenic epithelial cells.

Dietary omega-3 polyunsaturated fatty acids suppress expression of EZH2 in breast cancer cells

The polycomb group (PcG) protein, enhancer of zeste homologue 2 (EZH2), is overexpressed in several human malignancies including breast cancer. Aberrant expression of EZH2 has been associated with metastasis and poor prognosis in cancer patients. Despite the clear role of EZH2 in oncogenesis and therapy failure, not much is known about chemotherapeutics and chemopreventive agents that can suppress its expression and activity. Here, we show that dietary omega-3 (omega-3) polyunsaturated fatty acids (PUFAs) can regulate the expression of EZH2 in breast cancer cells. The treatment of breast cancer cells with omega-3 PUFAs, but not omega-6 PUFAs, led to downregulation of EZH2. Studies using proteosome inhibitor MG132 suggested that omega-3 PUFAs induce degradation of the PcG protein EZH2 through posttranslational mechanisms. Furthermore, downregulation of EZH2 by omega-3 PUFAs was accompanied by a decrease in histone 3 lysine 27 trimethylation (H3K27me3) activity of EZH2 and upregulation of E-cadherin and insulin-like growth factor binding protein 3, which are known targets of EZH2. Treatment with omega-3 PUFAs also led to decrease in invasion of breast cancer cells, an oncogenic phenotype that is known to be associated with EZH2. Thus, our studies suggest that the PcG protein EZH2 is an important target of omega-3 PUFAs and that downregulation of EZH2 may be involved in the mediation of anti-oncogenic and chemopreventive effects of omega-3 PUFAs.

Oleic acid promotes migration on MDA-MB-231 breast cancer cells through an arachidonic acid-dependent pathway

An association between dietary fatty, obesity and an increased risk of developing breast cancer has been suggested. In breast cancer cells, free fatty acids (FFAs) mediate biological effects including cell proliferation and ERK1/2 activation. However, the contribution of FFAs to tumor progression and metastasis through the regulation of cell migration has not been studied. We demonstrated here that stimulation on MDA-MB-231 breast cancer cells with oleic acid (OA) promotes an increase in focal adhesion kinase (FAK) phosphorylation, as revealed by site-specific antibodies that recognize the phosphorylation state of FAK at tyrosine-397 (Tyr-397), Tyr-577 and in vitro kinase assays. OA also promotes the migration of MDA-MB-231 cells. Treatment with Gi/Go proteins, phospholipase C (PLC), lipoxygenases (LOXs) and Src inhibitor prevents FAK phosphorylation and cell migration. In summary, our findings delineate a new signal transduction pathway, where OA mediates the production of arachidonic acid (AA), and then AA metabolites mediate FAK phosphorylation and cell migration in MDA-MB-231 breast cancer cells.

Differential expression of H19 and vitamin D3 upregulated protein 1 as a mechanism of the modulatory effects of high virgin olive oil and high corn oil diets on experimental mammary tumours

Dietary lipids have a role in the aetiology of breast cancer. We have reported earlier that a high corn oil diet downregulates H19 and vitamin D3 upregulated protein 1 (VDUP1) messenger RNA (mRNA) expression in rat dimethylbenz (alpha) anthracene-induced mammary adenocarcinomas in comparison with the control low-fat diet, this effect being associated with a higher degree of tumour malignancy. This result was compatible with the stimulating effect of this diet. In this study we have investigated the influence of a high extra virgin olive diet on H19 and VDUP1 mRNA and/or protein expression. We have shown earlier that this high-fat diet confers to the tumours a more benign phenotype in accordance with its potential protective effect on mammary cancer. We have also analysed the effects on the mRNA and protein expression of insulin-like growth factor-2 , in close relation with H19, and the expression and activity of the thioredoxin protein, negatively regulated by VDUP1. mRNA and protein expression were analysed by chemiluminescent northern blot and western blot, respectively. Thioredoxin activity was determined by the insulin-reducing assay. The results showed that the high olive oil diet does not change the tumour expression of H19 and VDUP1. Moreover, tumours from the animals fed this diet displayed higher levels of the insulin-like growth factor-2 mRNAs, which are related to a higher rate of degradation or a lower traducibility. Finally, tumour expression and activity levels of thioredoxin-1 protein did not change irrespective of the diet. These results suggest that the differential effects of high olive oil and high corn oil diets on mammary cancer are exerted by means of a different, specific influence on gene expression.

Are the olive oil and other dietary lipids related to cancer? Experimental evidence

There is a wealth of evidence supporting the relationship between dietary lipids and cancer, particularly those of the breast, colon and rectum and prostate. The main support comes from the international correlational studies and, especially, from experimental ones. The evidence from human analytical studies is less consistent because of several conflicting findings, probably due to methodological issues. Experimentally, it has been clearly demonstrated that quantity and type of dietary lipids as well as the particular critical phases of the carcinogenesis in which they act, are the essential factors in this relationship. Thus, whereas high dietary intake of n-6 polyunsaturated fatty acids (PUFA), primarily LA, and saturated fat has tumor-enhancing effects, long chain n-3 PUFA, CLA and GLA have inhibitory effects. Monounsaturated fatty acids (MUFA), mainly OA, present in high quantities in olive oil, seem to be protective although some inconsistent results have been reported. Bioactive compounds of virgin olive oil may also account for the protective effect of this oil, which is the main source of fat in the Mediterranean diet. Experimental studies have also provided evidence of several putative mechanisms of action of dietary lipids on cancer. Lipids can influence the hormonal status, modify cell membranes structure and function, cell signalling transduction pathways and gene expression, and modulate the function of the immune system. Although further studies are needed to evaluate and verify these mechanisms in humans, based on the multiple ways dietary lipids can act, they may have an important influence on tumorigenesis.

Dietary stearate reduces human breast cancer metastasis burden in athymic nude mice

Stearate is an 18-carbon saturated fatty acid found in many foods in the western diet, including beef and chocolate. Stearate has been shown to have anti-cancer properties during early stages of neoplastic progression. However, previous studies have not investigated the effect of dietary stearate on breast cancer metastasis. In this study, we present evidence that exogenously supplied dietary stearate dramatically reduces the size of tumors that formed from injected human breast cancer cells within the mammary fat pads of athymic nude mice by approximately 50% and partially inhibits breast cancer cell metastasis burden in the lungs in this mouse model system. This metastatic inhibition appears to be independent of primary tumor size, as stearate fed animals that had primary tumors comparable in size to littermates fed either a safflower oil enriched diet or a low fat diet had reduced lung metastasis. Also stearate fed mice sub-groups had different primary tumor sizes but no difference in metastasis. This anti-metastasis effect may be due, at least in part, to the ability of stearate to induce apoptosis in these human breast cancer cells. Overall, this study suggests the possibility of dietary manipulation with selected long-chain saturated fatty acids such as stearate as a potential adjuvant therapeutic strategy for breast cancer patients wishing to maximize the suppression of metastatic disease.

Oleic acid induces ERK1/2 activation and AP-1 DNA binding activity through a mechanism involving Src kinase and EGFR transactivation in breast cancer cells

GPR40 and GPR120 are G-protein-coupled receptors that can be activated by medium- and long-chain fatty acids. GPR40 is expressed in several breast cancer cell lines and its stimulation with oleic acid (OA) induces cell proliferation. However, the signal transduction pathways activated by OA have not been studied in detail. Our results demonstrate that both GPR40 and GPR120 are expressed in MCF-7 cells. Stimulation of MCF-7 and MDA-MB-231 cells with OA promoted the phosphorylation of ERK1/2 at Thr-202 and Tyr-204 and the formation of AP-1-DNA complex in a fashion dependent of Src kinase activity and EGFR transactivation. Furthermore, proliferation induced by OA is restricted to breast cancer cells in a fashion dependent of ERK1/2 activation and matrix metalloproteinases. In summary, our data indicate that proliferation induced by OA is restricted to breast cancer cells, and that ERK1/2 activation and AP-1-DNA complex formation are mediated by Src family kinases and transactivation of EGFR.

Arachidonic acid promotes FAK activation and migration in MDA-MB-231 breast cancer cells

Arachidonic acid (AA) is a common dietary n-6 polyunsaturated fatty acid that is present in an esterified form in cell membrane phospholipids, and it might be present in the extracellular microenvironment. In particular, AA promotes MAPK activation and mediates the adhesion of MDA-MB-435 breast cancer cells to type IV collagen. However, the signal transduction pathways mediated by AA have not been studied in detail. Our results demonstrate that stimulation of MDA-MB-231 breast cancer cells with AA promotes an increase in the phoshorylation of Src and FAK, as revealed by site-specific antibodies that recognized the phosphorylation state of Src at Tyr-418, and of FAK at tyrosine-397 and in vitro kinase assays. In addition, AA also induces an increase in the migration of MDA-MB-231 cells. In contrast, AA does not induce phosphorylation of FAK and an increase in cell migration of non-tumorigenic epithelial cells MCF10A. Inhibition of Gi/Go proteins, LOX and Src activity prevent FAK activation and cell migration. In conclusion, our results demonstrate, for the first time, that Gi/Go proteins, LOX and Src play an important role in FAK activation and cell migration induced by AA in MDA-MB-231 breast cancer cells.

Comparison of baseline dietary intake of Hispanic and matched non-Hispanic white breast cancer survivors enrolled in the Women's Healthy Eating and Living study

OBJECTIVE

To assess the reported baseline dietary intake of Hispanic and non-Hispanic white breast cancer survivors in the Women's Healthy Eating and Living study, a randomized plant-based dietary intervention clinical trial.

DESIGN

Dietary data from 4 days repeated 24-hour recalls within 3 weeks included daily total intake of energy, protein, carbohydrates, cholesterol, total fat, monounsaturated fat, saturated fat, polyunsaturated fat, fruit/vegetable servings, carotenoids, alcohol, caffeine, and percentage of energy from protein, carbohydrates, alcohol, and fats.

SUBJECTS

One hundred sixty-five Hispanic breast cancer survivors age-matched to 165 non-Hispanic white breast cancer survivors diagnosed with Stage I, II, or IIIA primary operable breast cancer.

STATISTICAL ANALYSES

Two-sample t tests and Wilcoxon rank sum tests to compare dietary intake, and logistic and ordinal logistic regression analyses to examine the association between ethnicity, alcohol, and lycopene consumption, while controlling for place of birth, education, body mass index, and time since diagnosis.

RESULTS

Hispanics were more likely to be foreign-born (P<0.001), less educated (P<0.0001) and to consume higher amounts of lycopene (P=0.029), while non-Hispanic whites were more likely to consume alcohol (P=0.001). However, no differences were observed in the average amounts of alcohol consumed or total percents of energy from alcohol. Both groups consumed more than five servings of fruits and vegetables daily. Being Hispanic remained a significant predictor of lower alcohol use (P=0.004) and higher lycopene consumption (P=0.005) after controlling for place of birth, education, body mass index, and time since diagnosis.

CONCLUSIONS

There are more similarities than differences in the dietary intake of Hispanic and non-Hispanic white breast cancer survivors in the Women's Healthy Eating and Living study. Further analysis is needed to determine if higher lycopene consumption shown among the Hispanic participants will translate to greater protection against breast cancer recurrence or increased survival.

Low-fat dietary pattern and risk of benign proliferative breast disease: a randomized, controlled dietary modification trial

Modifiable factors, including diet, might alter breast cancer risk. We used the Women's Health Initiative Dietary Modification trial to test the effect of the intervention on risk of benign proliferative breast disease, a condition associated with increased risk of, and considered to be on the pathway to, invasive breast cancer. The Women's Health Initiative Dietary Modification trial was a randomized, controlled, primary prevention trial conducted in 40 U.S. clinical centers from 1993 to 2005. A total of 48,835 postmenopausal women, ages 50 to 79 years, without prior breast cancer, were enrolled. Participants were randomly assigned to the dietary modification intervention group or to the comparison group. The intervention was designed to reduce total dietary fat intake to 20% of total energy intake, and to increase fruit and vegetable intake to > or =5 servings/d and intake of grain products to > or =6 servings/d, but resulted in smaller, albeit significant, changes in practice. Participants had biennial mammograms and regular clinical breast exams. We identified women who reported breast biopsies free of cancer, obtained the histologic sections, and subjected them to standardized central review. During follow-up (average, 7.7 years), 570 incident cases of benign proliferative breast disease were ascertained in the intervention group and 793 in the comparison group. The hazard ratio for the association between dietary modification and benign proliferative breast disease was 1.09 (95% confidence interval, 0.98-1.23). Risk varied by levels of baseline total vitamin D intake but it varied little by levels of other baseline variables. These results suggest that a modest reduction in fat intake and increase in fruit, vegetable, and grain intake do not alter the risk of benign proliferative breast disease.

Molecular mechanisms of the effects of olive oil and other dietary lipids on cancer

Cancer is one of the main causes of mortality worldwide. Geographical differences in incidence rates suggest a key effect of environmental factors, especially diet, in its aetiology. Epidemiologic and experimental studies have found a role of dietary lipids in cancer, particularly breast, colorectal, and prostate cancers. Their incidence in the Mediterranean countries, where the main source of fat is olive oil, is lower than in other areas of the world. Human studies about the effects of dietary lipids are little conclusive, probably due to methodological issues. On the other hand, experimental data have clearly demonstrated that the influence of dietary fats on cancer depends on the quantity and the type of lipids. Whereas a high intake of n-6 PUFA and saturated fat has tumor-enhancing effects, n-3 PUFA, conjugated linoleic acid and gamma-linolenic acid have inhibitory effects. Data regarding MUFA have not always been conclusive, but high olive oil diets seem to have protective effects. Such effects can be due to oleic acid, the main MUFA in olive oil, and to certain minor compounds such as squalene and phenolic compounds. This work aims to review the current knowledge about the relationship between dietary lipids and cancer, with a special emphasis on olive oil, and the molecular mechanisms underlying these effects: modifications on the carcinogenesis stages, hormonal status, cell membrane structure and function, signal transduction pathways, gene expression, and immune system.

Body mass index and intake of selected foods in African American men

BACKGROUND

There are minimal data on the relationship between dietary consumption of fats, vegetables, and fruits and body mass index (BMI) in African American men.

OBJECTIVE

This study tested the relationships between selected dietary consumption and BMI.

DESIGN

The sample was a community-based cohort of 204 African American Southern men who attended a free prostate cancer educational and screening program. The screening was part of an all-day African American celebration that included a health fair. Diet was assessed with a Brief Dietary Scale for Selected Food Intake and Preparation.

RESULTS

Most of the men were overweight (34%) or obese (47%). The majority of men ate their chicken (90%) and fish (96%) fried. Few men ate vegetables at supper (29.4%) or lunch (15.8%). Three fatty food items were significantly associated with BMI: leaving the chicken skin on chicken (p=.03); intake of low-fat or skim milk (p=.02); and cooking vegetables with butter (p=.03).

CONCLUSION

African American men need culturally appropriate dietary interventions to reduce obesity.

Soyfood Intake in the Prevention of Breast Cancer Risk in Women: A Meta-Analysis of Observational Epidemiological Studies

Many studies have suggested that the intake of soy products may protect against the occurrence of breast cancer because of the considerable amount of isoflavones they contain. To review the results of the observational studies, we performed this meta-analysis of the relevant literature. We searched Medline for reports that examined the association between soyfood consumption (or isoflavone intake) and breast cancer risk from January 1966 to April 2006. The random-effects model was used to estimate the pooled relative risk (RR). Twenty-one independent studies (14 case-control studies and 7 cohort studies) were included in the final analysis. The pooled RR of breast cancer for soyfood intake was 0.75 with a 95% CI of 0.59-0.95. As the main types of soyfood in Japan and China, tofu and miso showed clear protective effects. Isoflavone intake resulted in a 20% decrease in risk (RR = 0.81, 95% CI 0.67-0.99). The pooled RR varied little according to study stratification. When the studies published in Japanese and Chinese were added, the inverse associations between soyfood, tofu and breast cancer risk became slightly stronger. The weak association of miso was possibly due to the high concentration of salt in miso soup. In the present analysis, we did not find strong evidence for publication bias in the combination of the studies. This meta-analysis supported the hypotheses that soyfood intake may be associated with a decreased risk of breast cancer due to the isoflavones. Further epidemiological studies need to be conducted with more comprehensive information about the soyfood, and more accurate assessment of the isoflavones.

Milk Consumption in Relation to Incidence of Prostate, Breast, Colon, and Rectal Cancers: Is There an Independent Effect?

Milk contains a wide variety of ingredients, such as nutrients, hormones, and chemical contaminants. Whether milk consumption is associated with the risk of prostate, breast, colon, and rectal cancers is unclear and was evaluated in this study. Data on milk consumption for 9 time periods (1964-1994) and incidence rates of prostate, female breast, colon, and rectal cancers, mostly around 1993-1997, in 38 countries were obtained from the Food and Agriculture Organization and World Health Organization, respectively. Milk consumption was strongly correlated with incidence rates of prostate cancer (r = 0.65-0.69; all P < 0.0001) and breast cancer (r = 0.64-0.74; all P < 0.0001) in all the nine time periods examined. A modest positive correlation was found for colon and rectal cancers in both sexes (all P < 0.05, except for rectal cancer in the first three time periods). The previous findings remained essentially unchanged after adjustment for vegetable, alcohol, and cigarette consumption but disappeared after further adjustment for non-milk fat consumption, except for breast cancer in the last three time periods. The present study does not support an overall substantial effect of milk consumption on the risk of prostate, breast, colon, and rectal cancers at the population level.

Oleate promotes the proliferation of breast cancer cells via the G protein-coupled receptor GPR40

Evidence from epidemiological studies and animal models suggests a link between high levels of dietary fat intake and risk of breast cancer. In addition, obesity, in which circulating lipids are elevated, is associated with increased risk of various cancers. Relative to this point, we previously showed that oleate stimulates the proliferation of breast cancer cells and that phosphatidylinositol 3-kinase plays a role in this process. Nonetheless, questions remain regarding the precise mechanism(s) by which oleate promotes breast cancer cell growth. Pharmacological inhibitors of the GTP-binding proteins G(i)/G(o), phospholipase C, Src, and mitogenic-extracellular signal-regulated kinase 1/2 (MEK 1/2) decreased oleate-induced [3H]thymidine incorporation in the breast cancer cell line MDA-MB-231. In addition, oleate caused a rapid and transient rise in cytosolic Ca2+ and an increase in protein kinase B phosphorylation. Overexpressing in these cells the G protein-coupled receptor GPR40, a fatty acid receptor, amplified oleate-induced proliferation, whereas silencing the GPR40 gene using RNA interference decreased it. Overexpressing GPR40 in T47D and MCF-7 breast cancer cells that are poorly responsive to oleate allowed a robust proliferative action of oleate. The data indicate that the phospholipase C, MEK 1/2, Src, and phosphatidylinositol 3-kinase/protein kinase B signaling pathways are implicated in the proliferative signal induced by oleate and that these effects are mediated at least in part via the G protein-coupled receptor GPR40. The results suggest that GPR40 is implicated in the control of breast cancer cell growth by fatty acids and that GPR40 may provide a link between fat and cancer.

Oleic acid, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu (erbB-2) expression and synergistically enhances the growth inhibitory effects of trastuzumab (Herceptin) in breast cancer cells with Her-2/neu oncogene amplification

BACKGROUND

The relationship between the intake of olive oil, the richest dietary source of the monounsaturated fatty acid oleic acid (OA; 18:1n-9), and breast cancer risk and progression has become a controversial issue. Moreover, it has been suggested that the protective effects of olive oil against breast cancer may be due to some other components of the oil rather than to a direct effect of OA.

METHODS

Using flow cytometry, western blotting, immunofluorescence microscopy, metabolic status (MTT), soft-agar colony formation, enzymatic in situ labeling of apoptosis-induced DNA double-strand breaks (TUNEL assay analyses), and caspase-3-dependent poly-ADP ribose polymerase (PARP) cleavage assays, we characterized the effects of exogenous supplementation with OA on the expression of Her-2/neu oncogene, which plays an active role in breast cancer etiology and progression. In addition, we investigated the effects of OA on the efficacy of trastuzumab (Herceptin), a humanized monoclonal antibody binding with high affinity to the ectodomain of the Her-2/neu-coded p185(Her-2/neu) oncoprotein. To study these issues we used BT-474 and SKBr-3 breast cancer cells, which naturally exhibit amplification of the Her-2/neu oncogene.

RESULTS

Flow cytometric analyses demonstrated a dramatic (up to 46%) reduction of cell surface-associated p185(Her-2/neu) following treatment of the Her-2/neu-overexpressors BT-474 and SK-Br3 with OA. Indeed, this effect was comparable to that found following exposure to optimal concentrations of trastuzumab (up to 48% reduction with 20 microg/ml trastuzumab). Remarkably, the concurrent exposure to OA and suboptimal concentrations of trastuzumab (5 microg/ml) synergistically down-regulated Her-2/neu expression, as determined by flow cytometry (up to 70% reduction), immunoblotting, and immunofluorescence microscopy studies. The nature of the cytotoxic interaction between OA and trastuzumab revealed a strong synergism, as assessed by MTT-based cell viability and anchorage-independent soft-agar colony formation assays. Moreover, OA co-exposure synergistically enhanced trastuzumab efficacy towards Her-2/neu overexpressors by promoting DNA fragmentation associated with apoptotic cell death, as confirmed by TUNEL and caspase-3-dependent PARP cleavage. In addition, treatment with OA and trastuzumab dramatically increased both the expression and the nuclear accumulation of p27(Kip1), a cyclin-dependent kinase inhibitor playing a key role in the onset and progression of Her-2/neu-related breast cancer. Finally, OA co-exposure significantly enhanced the ability of trastuzumab to inhibit signaling pathways downstream of Her-2/neu, including phosphoproteins such as AKT and MAPK.

CONCLUSIONS

These findings demonstrate that OA, the main monounsaturated fatty acid of olive oil, suppresses Her-2/neu overexpression, which, in turn, interacts synergistically with anti-Her-2/neu immunotherapy by promoting apoptotic cell death of breast cancer cells with Her-2/neu oncogene amplification. This previously unrecognized property of OA offers a novel molecular mechanism by which individual fatty acids may regulate the malignant behavior of breast cancer cells and therefore be helpful in the design of future epidemiological studies and, eventually, dietary counseling.

Effects of an oncologist's recommendation to exercise on self-reported exercise behavior in newly diagnosed breast cancer survivors: a single-blind, randomized controlled trial

BACKGROUND

Increased attention has focused on exercise as a quality of life intervention for breast cancer survivors during and after adjuvant therapy.

PURPOSE

Our objective was to examine the effects of an oncologist's recommendation to exercise on self-reported exercise behavior in newly diagnosed breast cancer survivors attending their first adjuvant therapy consultation.

METHODS

Using a single-blinded, 3-armed, randomized controlled trial, 450 breast cancer survivors were randomly assigned to receive an oncologist exercise recommendation only, an oncologist exercise recommendation plus referral to an exercise specialist, or usual care. The primary outcome was self-reported total exercise (in metabolic equivalent [MET] hours per week) at 5 weeks postconsultation.

RESULTS

The follow-up assessment rate was 73% (329 of 450). Intention-to-treat analysis based on participants with follow-up data indicated a significant difference in total exercise in favor of the recommendation-only group over the usual care group (mean difference, 3.4 MET hr per week; 95% confidence interval [CI], 0.7-6.1 MET hr per week; p = .011). There was no significant difference between the recommendation-plus-referral group and the usual care group (mean difference, 1.5 MET hr per week; 95% CI, -1.0 to 4.0 MET hr per week; p = .244). Ancillary "on-treatment" analyzes showed that participants who recalled an exercise recommendation reported significantly more total exercise than participants who did not recall an exercise recommendation (mean difference, 4.1 MET hr per week: 95% CI, 1.9-6.4 MET hr per week; p < .001).

CONCLUSIONS

Our findings suggest that an oncologist recommendation may increase exercise behavior in newly diagnosed breast cancer survivors, particularly if it is recalled 1 week after the recommendation.

Dieta e câncer: um enfoque epidemiológico

Epidemiologistas que estudam câncer têm observado que a sua prevalência no mundo tem aumentado de maneira significativa no último século. Acredita-se que este resultado está relacionado, entre outros aspectos, com a industrialização e a urbanização ocorridas neste período. De fato, a morbi-mortalidade associada ao câncer observada em países desenvolvidos é maior do que em países em desenvolvimento. Além disso, algumas formas específicas de câncer, como o de cólon e reto, próstata e mama feminina, são mais freqüentes em países desenvolvidos, enquanto outras, como de estômago, esôfago e colo de útero têm maior incidência nos países em desenvolvimento. Padrões distintos de câncer também são observados entre indivíduos que emigram para um novo país ou região. Com base em estudos epidemiológicos, analisou-se a relação entre câncer e nutrição, e algumas modificações na alimentação que podem prevenir alguns tipos de cânceres.

High-Fat Corn Oil Diet Promotes the Development of High Histologic Grade Rat DMBA-Induced Mammary Adenocarcinomas, While High Olive Oil Diet Does Not

Effects of a high corn oil and a high olive oil diet on the histopathologic characteristics of rat dimethylbenz(alpha)anthracene-induced mammary adenocarcinomas were investigated in comparison with those of a control low-fat diet. Two experimental series (A and B) studied the influence of a high corn oil diet on the initiation and the promotion of mammary carcinogenesis, while another one (C) assessed the effects of the two dietary lipids on the promotion. Nine parameters have been analyzed and a new histologic grading method, adapted to rat tumors, has been applied in each carcinoma. High corn oil diets, particularly when acting as promoters, associated with higher-grade carcinomas than control (p < 0.05) and high olive oil groups. Stromal invasion and tumoral necrosis were more prominent and a prevailing cribriform pattern was observed (p < 0.05). High olive oil diet adenocarcinomas exhibited a predominantly low histologic grade and few necrotic and invasive areas, similar to the control, and they presented the highest percentage of papillary areas. Lymphoplasmacytic and mast cell infiltration were also influenced by the dietary lipids. Thus, high corn oil diet adenocarcinomas presented a higher degree of morphological malignancy than control and high olive oil tumors, which is in line with the greater clinical malignancy described in rats from the former group and the non-promoting effect of the high olive oil diet. As far as we are concerned, a similar histopathologic approach of the effects of the dietary lipids on experimental breast cancer has not been carried out up to now.

Effect of linoleic acid on proliferation and gene expression in the breast cancer cell line T47D

Human and animal studies have linked n-6 polyunsaturated fatty acids with mammary carcinogenesis. We investigated the cellular and molecular effects of linoleic acid on the human breast cancer cell line T47D. Linoleic acid had a stimulatory effect on the growth of T47D cells, associated with an increase in the proportion of cells in the S phase of the cell cycle. Microarray, functional group and quantitative PCR analyses indicate that linoleic acid may affect T47D cell growth by modulation of the estrogen receptor (ERalpha), the G13alpha G protein, and p38 MAP kinase gene expression as well genes involved in RNA transcription and cell cycle regulation.

Consumption of dairy products and the risk of breast cancer: a review of the literature

Differences in eating patterns and breast cancer rates across countries suggest that several dietary components, including dairy products, could affect breast cancer risk. However, dairy products are a diverse food group in terms of the factors that could potentially influence risk. Some dairy products, such as whole milk and many types of cheese, have a relatively high saturated fat content, which may increase risk. Moreover, milk products may contain contaminants such as pesticides, which have carcinogenic potential, and growth factors such as insulin-like growth factor I, which have been shown to promote breast cancer cell growth. In contrast, the calcium and vitamin D contents of dairy products have been hypothesized to reduce breast cancer risk. We reviewed the current epidemiologic literature on the relation between dairy product intakes and breast cancer risk, focusing primarily on the results of cohort and case-control studies. Most of the studies reviewed showed no consistent pattern of increased or decreased breast cancer risk with a high consumption of dairy products as a whole or when broken down into high-fat and low-fat dairy products, milk, cheese, or butter. Measurement error may have attenuated any modest association with dairy products. The available epidemiologic evidence does not support a strong association between the consumption of milk or other dairy products and breast cancer risk.

Existence of GPR40 functioning in a human breast cancer cell line, MCF-7

GPR40, which has recently been identified as a G-protein-coupled cell-surface receptor for long-chain fatty acids, was assessed in a human breast cancer cell line (MCF-7). We detected GPR40 mRNA by RT-PCR and found that oleate and linoleate, but not palmitate or stearate, caused an increase in cellular Ca(2+) concentrations, which was partially blocked by the pertussis toxin (PTX) treatment. We examined the expression of GPR40 mRNA by quantitative RT-PCR in the relation to cell number. It was significantly increased at the beginning and at the end of cell proliferation. These results indicate the possibility that GPR40 for long-chain fatty acids may be involved in cellular function such as cell proliferation, providing a new perspective for the action of long-chain fatty acids on mammary epithelial cells.