Omega-3 fatty acids for the prevention of breast cancer: an update and state of the science

Single nucleotide polymorphism of fatty acid desaturase gene and breast cancer risk in estrogen receptor subtype

BACKGROUND

Breast cancer (BC) is the most common cancer of women and the second most common cancer overall globally. Data suggest that the plasma concentration of omega fatty acids (n-3 and n-6) and the impact of the genetic variant are associated with diet-related inflammatory disease, BC. This study was aimed to find an association between genetic variant rs174537 of fatty acid desaturase gene 1(FADS 1) and breast cancer estrogen receptor subtype.

METHODOLOGY

Hundred and two blood samples from women were quantified for fatty acids by gas chromatography. SNP rs 174537(G > T) showed maximum variability and the strongest genetic determinant in the Genome-wide association study were genotyped using Sanger sequencing.

RESULTS

The highest tertile of ALA showed a significantly reduced risk of BC compared to the lowest tertile (OR = 0.2, 95 %CL = 0.1-1.14, P = 0.03). Median values of ALA were higher in GT/TT genotype in ER +ve molecular subtype (P = 0.03) and DPA was higher in GG genotype of ER-ve molecular subtype (P = 0.037). When both the groups were put together the highest tertile of GG tertile showed significantly reduced risk of BC compared with the other lowest tertiles of GG and GT/TT genotypes (OR, 95% CL = 0.45(0.2-0.9).

CONCLUSION

The high levels of arachidonic acid and low levels of n-3 fatty acids result in a pro-inflammatory milieu and that these pro-inflammatory effects might contribute to BC. We conclude that the individuals with genetically determined lower activity of FADS1(minor allele T) will derive greater advantage from n-3 FAs than those with higher FADS1 activity (G allele) and reduce the BC risk.

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.

Biotin anchored nanostructured lipid carriers for targeted delivery of doxorubicin in management of mammary gland carcinoma through regulation of apoptotic modulator

Mammary gland tumour has the highest incidence rate and mortality in women, worldwide. The present study envisaged a molecularly targeted nanostructured lipid carrier (NLCs) for doxorubicin (Dox) delivery capable of inducing cellular apoptosis in mammary gland tumour. NLCs were prepared utilizing Perilla frutescens oil (54-69% ω3-fatty acid) as liquid lipid to enhance entrapment of Dox through molecular ion pairing. Biotin decorated NLCs (b-Dox-NLCs) were evaluated in vitro and in vivo. The b-Dox-NLCs showed particle size of 105.2 ± 3.5 nm, zeta potential -35 ± 2 mV, entrapment 99.15 ± 1.71%, drug content 19.67 ± 2.6 mg.g-1, biotin content 5.85 ± 0.64 µg.g-1 and drug release 98.67 ± 2.43% (facilitated by acidic microenvironment) respectively. MTT assay and Flow cytometric analysis revealed higher anti-proliferative capability of b-Dox-NLCs to force apoptosis in MCF-7 cell line vis-à-vis marketed Dox, evidenced by reactive oxygen species level and mitochondrial membrane potential mediated apoptosis. Enhanced antitumor targeting, therapeutic safety and efficacy was exhibited by b-Dox-NLCs, as investigated through tumour volume, animal survival, weight variation, cardiotoxicity and biodistribution studies in 7,12-Dimethylbenz[a]anthracene induced mammary gland tumour. Immunoblotting assay demonstrated b-Dox-NLCs downregulated anti-apoptotic proteins, i.e. bcl-2, MMP-9 while upregulated pro-apoptotic proteins, i.e. caspase-9, p16 and BAX. The experimental results suggest that biotinylated ω3-fatty acid augmented NLCs loaded with Dox are capable of inducing programmed cell death in mammary tumour and can be utilized as safe and effective delivery system with enhanced potential for mammary gland carcinoma therapy.

Docosahexaenoic Acid in Combination with Dietary Energy Restriction for Reducing the Risk of Obesity Related Breast Cancer

There is strong evidence that obesity poses a significant risk factor for postmenopausal breast cancer. There are multiple mechanisms by which obesity can predispose to breast cancer, prominent among which is the creation of a pro-inflammatory milieu systemically in the visceral and subcutaneous tissue, as well as locally in the breast. Although dietary intervention studies have shown in general a favorable effect on biomarkers of breast cancer risk, it is still unclear whether losing excess weight will lower the risk. In this manuscript, we will review the evidence that omega-3 fatty acids, and among them docosahexaenoic acid (DHA) in particular, may reduce the risk of obesity related breast cancer primarily because of their pleotropic effects which target many of the systemic and local oncogenic pathways activated by excess weight. We will also review the evidence indicating that intentional weight loss (IWL) induced by dietary energy restriction (DER) will augment the tumor protective effect of DHA because of its complementary mechanisms of action and its ability to reverse the obesity-induced alterations in fatty acid metabolism predisposing to carcinogenesis. We believe that the combination of DER and DHA is a promising safe and effective intervention for reducing obesity-related breast cancer risk which needs to be validated in appropriately designed prospective, randomized clinical trials.

Implications of dietary ω-3 and ω-6 polyunsaturated fatty acids in breast cancer

Breast cancer represents one of the most common forms of cancer in women worldwide, with an increase in the number of newly diagnosed patients in the last decade. The role of fatty acids, particularly of a diet rich in ω-3 and ω-6 polyunsaturated fatty acids (PUFAs), in breast cancer development is not fully understood and remains controversial due to their complex mechanism of action. However, a large number of animal models and cell culture studies have demonstrated that high levels of ω-3 PUFAs have an inhibitory role in the development and progression of breast cancer, compared to ω-6 PUFAs. The present review focused on recent studies regarding the correlation between dietary PUFAs and breast cancer development, and aimed to emphasize the main molecular mechanisms involved in the modification of cell membrane structure and function, modulation of signal transduction pathways, gene expression regulation, and antiangiogenic and antimetastatic effects. Furthermore, the anticancer role of ω-3 PUFAs through the modulation of microRNA expression levels was also reviewed.

Recommendations of the Spanish Menopause Society on the consumption of omega-3 polyunsaturated fatty acids by postmenopausal women

The consumption of long-chain omega-3 polyunsaturated fatty acids (LCO3-PUFAs) has shown a great variety of beneficial effects, including cardiovascular, metabolic and inflammatory effects, which make them interesting for the postmenopausal woman. Because LCO3-PUFAs could be effective and safe during this period, a panel of experts from the Spanish Menopause Society met to establish a set of recommendations for their use in postmenopausal women based on the best available evidence. The decrease in triglycerides is the most consistent effect observed with LCO3-PUFAs (at doses greater than 3g/day). In addition, LCO3-PUFAs have antiarrhythmic effects, reduce blood pressure, improve depressive and psychotic symptoms, and do not increase the risk of cancer. However, further studies are needed to confirm the benefit of LCO3-PUFAs in the relief of menopause symptoms and osteoporosis.

Immunomodulatory Effectiveness of Fish Oil and omega-3 Fatty Acids in Human Non-melanoma Skin Carcinoma Cells

Fish oil is composed of various fatty acids among which omega-3 fatty acids are considered as most beneficial. The effects of fish oil on the activity of a topical anticancer drug, imiquimod, and the immunomodulatory activity of omega-3 fatty acids was investigated in human basal and squamous cell carcinoma cell lines. Imiquimod-fish oil mixture exhibited higher carcinoma cell growth inhibition and immunomodulatory activity than imiquimod alone, especially against squamous cell carcinoma cells. Omega-3 fatty acids exhibited growth inhibition of both basal cell and squamous cell carcinoma cell lines and modulated the immune response. Omega-3 fatty acids of fish oil serve as inducers of interleukin-10, an anti-inflammatory cytokine, and as suppressors of interleukin-6 and tumor necrosis factor-alpha, which not only depress tumor growth but also adequately control the inflammatory side effects of imiquimod. Thus, imiquimod administration with fish oil could be beneficial for inhibition of non-melanoma skin carcinoma cells but further in vivo studies are needed to understand their role in skin cancer.

Incorporation of eicosapentaenioic and docosahexaenoic acids into breast adipose tissue of women at high risk of breast cancer: a randomized clinical trial of dietary fish and n-3 fatty acid capsules

SCOPE

The fatty acid profile of dietary lipids is reflected in mammary adipose tissue and may influence mammary gland biology and cancer risk. To determine the effects of fish consumption on breast adipose tissue fatty acids, we conducted a study of fish versus n-3 PUFA supplements in women at increased risk of breast cancer.

METHODS AND RESULTS

High risk women were randomized to comparable doses of marine n-3 PUFAs as canned salmon + albacore or capsules for 3 months. Pre- and posttreatment fatty acid profiles were obtained by GC. Dietary fish (n = 12) and n-3 PUFA capsules (n = 13) yielded increased eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in plasma (p < 0.0001), erythrocyte membranes (p < 0.0001), and breast fat (p < 0.01) at 3 months. Women taking capsules had higher plasma and erythrocyte membrane EPA changes (∼four versus twofold, p = 0.002), without significant differences in DHA. Increases in breast adipose EPA, DHA were similar for both groups. Higher BMI correlated with smaller changes in plasma, erythrocyte membrane EPA, and breast adipose EPA, DHA. Adherence was excellent at 93.9% overall and higher in the fish arm (p = 0.01).

CONCLUSION

Fish provides an excellent source of n-3 PUFAs that increases breast adipose EPA, DHA similar to supplements and represents a well-tolerated intervention for future studies of the impact of n-3 PUFAs and dietary patterns on breast cancer.

Breast cancer prevention across the cancer care continuum

OBJECTIVES

To review the current state of breast cancer prevention from primary prevention through survivorship, highlight cross-cutting issues, and discuss strategies for clinical integration and future research.

DATA SOURCES

Published articles between 1985 and 2015 and original research.

CONCLUSION

Cancer risk persists across the lifespan. Interprofessional strategies to reduce morbidity and mortality from cancer include primary, secondary, and tertiary prevention (survivorship). Prevention strategies across the cancer care continuum are cross-cutting and focus on measures to: prevent the onset of disease, identify and treat asymptomatic persons who have already developed risk factors or preclinical disease, and restore function, minimize the negative effects of disease, and prevent disease-related complications.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses and advanced practice nurses are vital in the delivery of breast cancer prevention strategies.

Omega-3 fatty acids reduce obesity-induced tumor progression independent of GPR120 in a mouse model of postmenopausal breast cancer

Obesity and inflammation are both risk factors for a variety of cancers, including breast cancer in postmenopausal women. Intake of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) decreases the risk of breast cancer, and also reduces obesity-associated inflammation and insulin resistance, but whether the two effects are related is currently unknown. We tested this hypothesis in a postmenopausal breast cancer model using ovariectomized, immune-competent female mice orthotopically injected with Py230 mammary tumor cells. Obesity, whether triggered genetically or by high-fat diet (HFD) feeding, increased inflammation in the mammary fat pad and promoted mammary tumorigenesis. The presence of tumor cells in the mammary fat pad further enhanced the local inflammatory milieu. Tumor necrosis factor-alpha (TNF-α) was the most highly upregulated cytokine in the obese mammary fat pad, and we observed that TNF-α dose-dependently stimulated Py230 cell growth in vitro. An ω-3 PUFA-enriched HFD (referred to as fish oil diet, FOD) reduced inflammation in the obese mammary fat pad in the absence of tumor cells and inhibited Py230 tumor growth in vivo. Although some anti-inflammatory effects of ω-3 PUFAs were previously shown to be mediated by the G-protein-coupled receptor 120 (GPR120), the FOD reduced Py230 tumor burden in GPR120-deficient mice to a similar degree as observed in wild-type mice, indicating that the effect of FOD to reduce tumor growth does not require GPR120 in the host mouse. Instead, in vitro studies demonstrated that ω-3 PUFAs act directly on tumor cells to activate c-Jun N-terminal kinase, inhibit proliferation and induce apoptosis. Our results show that obesity promotes mammary tumor progression in this model of postmenopausal breast cancer and that ω-3 PUFAs, independent of GPR120, inhibit mammary tumor progression in obese mice.

Mammary tumour development is dose-dependently inhibited by n-3 polyunsaturated fatty acids in the MMTV-neu(ndl)-YD5 transgenic mouse model

Background

Breast cancer is attributable to modifiable risk factors including the intake of dietary n-3 polyunsaturated fatty acids (PUFA). A key piece of evidence, yet to be addressed, that would demonstrate a causal relationship between n-3 PUFA and breast cancer, is a dose-dependent effect of n-3 PUFA on tumour outcomes. Thus, the objective of the present study was to determine whether n-3 PUFA reduces mammary gland tumor outcomes in a dose-dependent manner in female MMTV-neu(ndl)-YD5 transgenic mice, an aggressive model of human breast cancer.

Methods

Harems were provided one of three experimental diets comprised of 0, 3 or 9% (w/w) menhaden fish oil containing n-3 PUFA. Female offspring were weaned onto the same parental diet and maintained on their respective diet for 20 weeks. Tumour onset, size and multiplicity were measured throughout the study. Fatty acid composition of mammary gland and tumours were determined by gas–liquid chromatography.

Results

Tumour size was significantly (p < 0.05) reduced in a dose-dependent manner. n-3 PUFA were also incorporated in a dose-dependent manner; differential incorporation was observed for eicosapentaenoic and docosapentaenoic acids into mammary gland tissue, while docosahexaenoic acid was preferentially incorporated into tumours.

Conclusion

Overall, the present study provides fundamental knowledge about the dose-dependent effect of n-3 PUFA on tumour outcomes in a pre-clinical model and also sheds light on the differential role of individual n-3 PUFA on tumour outcomes.

Obesity and cancer pathogenesis

Overweight and obesity have reached pandemic levels on a worldwide basis and are associated with increased risk and worse prognosis for many but not all malignancies. Pathophysiologic processes that affect this association are reviewed, with a focus on the relationship between type 2 diabetes mellitus and cancer, lessons learned from the use of murine models to study the association, the impact of obesity on pancreatic cancer, the effects of dietary fats and cholesterol on cancer promotion, and the mechanisms by which the intestinal microbiome affects obesity and cancer.