Carotenoids, vitamin A, and estrogen receptor status in breast cancer

Biochemical and Immunological implications of Lutein and Zeaxanthin

Throughout history, nature has been acknowledged for being a primordial source of various bioactive molecules in which human macular carotenoids are gaining significant attention. Among 750 natural carotenoids, lutein, zeaxanthin and their oxidative metabolites are selectively accumulated in the macular region of living beings. Due to their vast applications in food, feed, pharmaceutical and nutraceuticals industries, the global market of lutein and zeaxanthin is continuously expanding but chemical synthesis, extraction and purification of these compounds from their natural repertoire e.g., plants, is somewhat costly and technically challenging. In this regard microbial as well as microalgal carotenoids are considered as an attractive alternative to aforementioned challenges. Through the techniques of genetic engineering and gene-editing tools like CRISPR/Cas9, the overproduction of lutein and zeaxanthin in microorganisms can be achieved but the commercial scale applications of such procedures needs to be done. Moreover, these carotenoids are highly unstable and susceptible to thermal and oxidative degradation. Therefore, esterification of these xanthophylls and microencapsulation with appropriate wall materials can increase their shelf-life and enhance their application in food industry. With their potent antioxidant activities, these carotenoids are emerging as molecules of vital importance in chronic degenerative, malignancies and antiviral diseases. Therefore, more research needs to be done to further expand the applications of lutein and zeaxanthin.

Immune enhancement activities of silk lutein extract from Bombyx mori cocoons

Background

Declining immune function poses an important clinical challenge worldwide and supplementation with natural products that possessing immune enhancing properties is a promising approach for preventing or delaying immune function decline. Cocoons from yellow silkworms are a significant source of lutein, and this unexplored silk extract could be a viable alternative source for dietary lutein. This study assessed immunomodulatory activities of the silk lutein extract. Female BALB/c mice orally received lutein, either as silk or marigold extracts (10 or 20 mg/kg daily), or vehicle only (1% tween 80 in PBS pH 7.4) for 4 weeks. Natural killer (NK) cell activity, specific antibody production, lymphocyte subpopulations, mitogen-induced lymphocyte proliferation, and cytokine production were examined.

Results

Silk lutein extract increased NK cell activity, and the effect was dose-related whereas marigold lutein extract was ineffective. Silk lutein extract dose-dependently enhanced antibody production in pre-immunized mice but marigold lutein extract had no effect. Feeding with silk lutein extract increased the populations of CD3+ and CD4 + CD3 + cells. Silk lutein extract also stimulated concanavalin A- and lipopolysaccharide-induced proliferations of T and B lymphocytes, respectively. Moreover, silk lutein extract increased IL-2 and IFN-γ production while the effect of marigold lutein extract was undetectable.

Conclusions

Together, silk lutein extract enhanced both innate and adaptive immune functions. This preparation may prove to be an effective supplement for strengthened immunity.

Plant sterols as anticancer nutrients: evidence for their role in breast cancer

While many factors are involved in the etiology of cancer, it has been clearly established that diet significantly impacts one’s risk for this disease. More recently, specific food components have been identified which are uniquely beneficial in mitigating the risk of specific cancer subtypes. Plant sterols are well known for their effects on blood cholesterol levels, however research into their potential role in mitigating cancer risk remains in its infancy. As outlined in this review, the cholesterol modulating actions of plant sterols may overlap with their anti-cancer actions. Breast cancer is the most common malignancy affecting women and there remains a need for effective adjuvant therapies for this disease, for which plant sterols may play a distinctive role.

Carotenoids: actual knowledge on food sources, intakes, stability and bioavailability and their protective role in humans

Carotenoids are one of the major food micronutrients in human diets and the overall objective of this review is to re-examine the role of carotenoids in human nutrition. We have emphasized the attention on the following carotenoids present in food and human tissues: beta-carotene, beta-cryptoxanthin, alpha-carotene, lycopene, lutein and zeaxanthin; we have reported the major food sources and dietary intake of these compounds. We have tried to summarize positive and negative effects of food processing, storage, cooking on carotenoid content and carotenoid bioavailability. In particular, we have evidenced the possibility to improve carotenoids bioavailability in accordance with changes and variations of technology procedures.

Intake of fruits, and vegetables in relation to breast cancer risk by hormone receptor status

SUMMARY

The inconsistent associations between fruit and vegetable intake and breast cancer risk may be due to heterogeneity of associations by estrogen (ER) and progesterone receptor (PR) status of the tumors. We evaluated this hypothesis in a large (2,386 cases and 2,503 controls) population-based case-control study in Poland, conducted between 2000 and 2003. We observed significant associations between reduced overall risk of breast cancer and increasing levels of total fruit intake (odds ratio (OR) for highest versus lowest quartile = 0.76, 95%CI = 0.63-0.91; p-trend = 0.01), but not for total vegetable intake (1.13 (0.93-1.37), p-trend = 0.25), after controlling for age, energy intake and known risk factors for breast cancer. The inverse association with total fruit intake was stronger for risk of ER+ (0.69 (0.54-0.88), p-trend = 0.01) than ER- tumors (0.89 (0.67-1.19), p-trend = 0.57) (p-heterogeneity = 0.02). In conclusion, this study suggests that fruit intake might have differential associations for breast tumor subtypes defined by ER status.

Effect of dietary intake of phytoestrogens on estrogen receptor status in premenopausal women with breast cancer

Although many dietary studies have focused on breast cancer risk, few have examined dietary influence on tumor characteristics such as estrogen receptor (ER) status. Because phytoestrogens may modulate hormone levels and ER expression, we analyzed ER status and phytoestrogen intake in a case-case study of 124 premenopausal breast cancer patients. We assessed intake with a food-frequency questionnaire and obtained ER status from medical records. Rather than focusing on risk, we evaluated whether low intakes were more strongly associated with ER-negative tumors than with ER-positive disease. In logistic regression adjusting for potential confounders, threefold greater risks of ER-negative tumors relative to ER-positive tumors were associated with low intake of the isoflavones genistein (odds ratio, OR=3.50; 95% confidence interval, CI=1.43-8.58) and daidzein (OR=3.10; 95% CI=1.31-7.30). Low intake of the flavonoid kaempferol (OR=0.36; 95% CI=0.16-0.83), the trace element boron (OR=0.33; 95% CI=0.13-0.83), and the phytosterol beta-sitosterol (OR=0.42; 95% CI=0.18-0.98) were associated with decreased risk of ER-negative tumors relative to ER-positive disease. Other phytoestrogens were not significantly associated with ER status. Thus, in premenopausal patients, some phytoestrogens may affect breast carcinogenesis by influencing ER status. Such findings suggest new directions for mechanistic research on dietary factors in breast carcinogenesis that may have relevance for prevention and clinical treatment.

Lutein and Zeaxanthin and Their Potential Roles in Disease Prevention

Lutein and zeaxanthin are xanthophyll carotenoids found particularly in dark-green leafy vegetables and in egg yolks. They are widely distributed in tissues and are the principal carotenoids in the eye lens and macular region of the retina. Epidemiologic studies indicating an inverse relationship between xanthophyll intake or status and both cataract and age-related macular degeneration suggest these compounds can play a protective role in the eye. Some observational studies have also shown these xanthophylls may help reduce the risk of certain types of cancer, particularly those of the breast and lung. Emerging studies suggest as well a potential contribution of lutein and zeaxanthin to the prevention of heart disease and stroke. Even as the evidence for a role of lutein and zeaxanthin in disease prevention continues to evolve, particularly from human studies directed to their bioavailability, metabolism, and dose-response relationships with intermediary biomarkers and clinical outcomes, it is worth noting that recommendations to consume foods rich in xanthophylls are consistent with current dietary guidelines.

Fruits, Vegetables, and Micronutrients in Relation to Breast Cancer Modified by Menopause and Hormone Receptor Status

Whether fruit, vegetable, and antioxidant micronutrient consumption is associated with a reduction in breast cancer incidence remains unresolved. To address this issue, we analyzed data from a large population-based case-control study, with consideration given to whether the associations varied with menopausal status or with clinical characteristics of the cases' disease. Study participants completed a modified Block food frequency questionnaire, which included assessment of the frequency and portion sizes of 13 fruits and fruit juices and 16 vegetables and the use of multiple and single vitamin supplements. Statistical analyses were done on 1,463 cases and 1,500 controls. Among postmenopausal women, reduced odds ratios [OR; 95% confidence intervals (95% CI)] were noted for the highest fifth, as compared with the lowest fifth, of intake of any vegetables [0.63 (0.46–0.86); P for trend < 0.01] and leafy vegetables [0.66 (0.50–0.86); P for trend = 0.03] after controlling for age and energy intake. Adjusted ORs (95% CIs) were also decreased for postmenopausal breast cancer in relation to high intake of carotenoids, α-carotene, β-carotene, lutein, and particularly lycopene [0.66 (0.48–0.90); P for trend = 0.03]. Inverse associations for fruits and vegetables were stronger for postmenopausal women with estrogen receptor (ER)+ tumors (OR, 0.65; 95% CI, 0.51–0.82) than ER− tumors (OR, 0.92; 95% CI, 0.64–1.32), but results were less consistent for micronutrients. No similarly reduced associations were observed among premenopausal women. ORs did not appreciably differ by in situ or invasive breast cancer or by whether cases had begun chemotherapy. Our results support an inverse association for fruit and vegetable intake among postmenopausal but not premenopausal breast cancer, which may be more pronounced among women with ER+ tumors.

Fish Intake Is Positively Associated with Breast Cancer Incidence Rate

Animal studies have, in general, been supportive of a protective effect of fish and fish (n-3) PUFA against breast cancer risk; but the epidemiologic evidence of such a relationship is limited. Case-control and cohort studies have rarely shown significant associations. The association between total fish intake and the effect of fat content and preparation method of the fish, in relation to the incidence rate ratios of breast cancer, were investigated among postmenopausal women. We also investigated the effect of fish intake with respect to estrogen receptor expression of breast cancer tumors. A total of 23,693 postmenopausal women from the prospective study "Diet, Cancer and Health" were included in the study. During follow-up, 424 women were diagnosed with breast cancer. The incidence rate ratio (IRR) and 95% CI per each additional 25 g of mean daily intake of fish were 1.13 (CI, 1.03-1.23). Analysis of fatty fish gave IRR of 1.11 (CI, 0.91-1.34), and the result for lean fish was 1.13 (CI, 0.99-1.29). When fish intake was stratified into three types of preparation methods, the IRR for fried fish was 1.09 (CI, 0.95-1.25), for boiled fish 1.09 (CI, 0.85-1.42), and for processed fish 1.12 (CI, 0.93-1.34). The IRR per additional 25 g of mean daily intake of fish was 1.14 (CI, 1.03-1.26) for estrogen receptor-positive (ER+) and 1.00 (CI, 0.81-1.24) for estrogen receptor-negative (ER-) breast cancer. In conclusion, this study showed that higher intakes of fish were significantly associated with higher incidence rates of breast cancer. The association was present only for development of ER+ breast cancer.

Fruits and vegetables intake differentially affects estrogen receptor negative and positive breast cancer incidence rates

Despite intensive research, the evidence for a protective effect of fruits and vegetables on breast cancer risk remains inconclusive. Other risk factors for breast cancer seem to vary with the estrogen receptor status of the breast tumor, and it is thus possible that the inconsistent results regarding a preventive effect of fruits and vegetables are due to lack of controlling for estrogen receptor status. The objective of this study was to investigate the effect of fruit and vegetable intake on postmenopausal breast cancer and explore whether the estrogen receptor status of the tumor modifies this relation. Postmenopausal women (n = 23,798; aged 50-64 y) provided information about diet and established risk factors for breast cancer in the cohort "Diet, Cancer and Health." During follow-up, 425 cases were diagnosed with breast cancer. Associations between intake of fruits and vegetables and the breast cancer rate were analyzed using Cox's regression model. The association for all breast cancers was an incidence rate ratio (IRR) of 1.02 (95% CI, 0.98-1.06) per 100 g/d increment of total intake of fruits, vegetables and juice. For estrogen receptor-positive (ER(+)) breast cancer, a borderline significant increase in the rate was seen, IRR: 1.05 (95% CI, 1.00-1.10), whereas a preventive effect was seen for estrogen receptor-negative (ER(-)) breast cancers, IRR: 0.90 (95% CI, 0.81-0.99). In conclusion, we did not find the overall breast cancer rate to be associated with the intake of fruits and vegetables, but there seemed to be different effects for ER(+) and ER(-) breast cancer.

Dietary intake of selected fatty acids, cholesterol and carotenoids and estrogen receptor status in premenopausal breast cancer patients

Although a wealth of research has focused on the influence of diet on breast cancer risk, the relationships between dietary factors and tumor characteristics of breast cancer, like estrogen receptor (ER) status, are not well characterized. In a case-case study, we evaluated self-reported dietary intake for five individual carotenoids, selected fatty acids, and cholesterol 1 year before diagnosis in 34 premenopausal breast cancer patients with ER-negative tumors and 86 premenopausal breast cancer patients with ER-positive tumors from The University of Texas M. D. Anderson Cancer Center. In multivariate logistic regression analysis adjusted for age, body mass index, and ethnicity, high intakes of linoleic acid were associated with more than a threefold greater risk of ER-negative disease than ER-positive disease (odds ratio (OR) = 3.48, 95% confidence interval (CI) = 1.42-8.54), whereas high cholesterol intake was associated with lower risk of ER-negative disease (OR = 0.35, 95% CI = 0.14-0.92). In a model evaluating carotenoids, selected fatty acids, and cholesterol together, the association with high intake of linoleic acid remained statistically significant (OR = 3.96,95% CI = 1.53-10.25), while those for high intake of cholesterol (OR = 0.38, 95% CI = 0.14-1.03) and low intake of cryptoxanthin (OR = 0.43, 95% CI = 0.17-1.06) were of marginal significance. While no striking associations were observed for the intakes of total carotenoids, selected fatty acids, and cholesterol, our analysis revealed an association for the consumption of a specific fatty acid (i.e., linoleic acid), suggesting dietary influence of this factor on ER status in premenopausal breast cancer patients. However, larger studies are needed to clarify the role of micronutrients in ER status in breast cancer.

Retinoids, carotenoids, and human breast cancer cell cultures: a review of differential effects

Cancer of the breast is the most common incident cancer and cause of death from cancer in women. Several epidemiologic studies have reported a significant inverse relationship between the intake of vitamin A and/or provitamin A-rich foods and the incidence of certain cancers, including breast cancer. A large number of studies have been conducted to determine the effect of retinoids (all-trans-retinoic acid, in particular), and to a lesser extent of carotenoids, on breast cancer using cell culture models. In general, the results of these studies demonstrate beneficial effects of all-trans-retinoic acid on different breast cancer cells. This review compares studies conducted in different laboratories using retinoids and carotenoids as treatments for breast cancer cells and suggests what may be the underlying reasons for the differential effects of these compounds on the same cell lines.

Involvement of nuclear steroid/thyroid/retinoid receptors and of protein kinases in the regulation of growth and of c-erbB and retinoic acid receptor expression in MCF-7 breast cancer cells

Nuclear steroid/thyroid/retinoid receptors and c-erbB membrane receptor tyrosine kinases control epithelial growth and differentiation. Retinoid receptors can dimerize with the vitamin D receptor, the glucocorticoid receptor or the thyroid receptor. Furthermore, multiple c-erbB receptor dimers have been identified. It has been shown that some of these receptor pathways communicate with each other via cross-connected regulatory networks. Molecular interactions between retinoid receptors or estrogen receptors (ER) and c-erbB-2, and between ER and retinoic acid receptor(RAR)-alpha have been reported. Here, we demonstrate the effects of steroids/thyroids/retinoids and of activators of protein kinase A (forskolin, Forsk) and C (12-O-tetradecanoylphorbol-13-acetate, TPA), on growth and expression of c-erbB and RARs in MCF-7 breast cancer cells, which contain high levels of RAR-alpha and -gamma, and which express significant amounts of c-erbB-2 and -3. All trans-retinoic acid (tRA), the anti-estrogen ICI 182 780 (ICI), Forsk and TPA reduced, whereas triiodothyronine and 17beta-estradiol (E2) stimulated cell growth. Flow cytometry revealed that tRA and E2 reduced c-erbB-2 and -3, whereas tamoxifen, Forsk and TPA up-regulated c-erbB-2. c-erbB-3 was co-regulated with c-erbB-2. Northern analysis demonstrated that RAR-alpha was down-regulated by dexamethasone, ICI, and TPA, whereas vitamin D3 and E2 up-regulated RAR-alpha. RAR-gamma expression was less responsive to such treatment, being reduced only by ICI and Forsk. These data indicate that nuclear receptor and protein kinase signaling communicate with each other and control the expression of RARs and c-erbB receptors. Efficient growth control requires the coordinated interplay of both receptor systems.

Dietary lutein but not astaxanthin or beta-carotene increases pim-1 gene expression in murine lymphocytes

This study investigates the effect of dietary carotenoids on pim-1 gene expression in mouse splenocytes. Female BALB/c mice were fed 0%, 0.02%, or 0.4% astaxanthin, beta-carotene, and lutein for two weeks. Plasma and liver were obtained for the analysis of carotenoids. Splenocytes were isolated and cultured in the presence of concanavalin A, and the level of pim-1 mRNA was determined by Northern blot analysis. None of the carotenoids were detectable in the plasma and liver of unsupplemented mice. In plasma the concentration of astaxanthin (4.9-54.7 mumol/l) was dramatically higher than that of lutein (1.4-2.0 mumol/l) and beta-carotene (0.1-0.7 mumol/l). Carotenoid uptake by the spleen but not the liver reflected that observed in plasma. In mice fed 0.4% of each carotenoid, the absolute concentration of the carotenoid in the liver was highest for astaxanthin (24 nmol/g) followed by beta-carotene (7.5 nmol/g) and lutein (1.58 nmol/g). Mice fed lutein showed a dose-related increase in pim-1 mRNA expression. The steady-state level of pim-1 mRNA in mice fed 0.4% lutein was sixfold higher than in mice fed 0.02% lutein. In contrast, dietary astaxanthin and beta-carotene did not affect pim-1 expression. Therefore, an increase in pim-1 mRNA was observed in splenocytes stimulated with concanavalin A in lutein-fed mice. This appears to be a unique effect of lutein and may be associated with its antitumor activity observed in vivo.

Dietary lutein from marigold extract inhibits mammary tumor development in BALB/c mice

High levels of dietary lutein can inhibit mammary tumor growth in mice. However, the antitumor effect of low levels of dietary lutein on mammary tumors is unavailable. Female BALB/c mice and the WAZ-2T (-SA) mammary tumor cell line were used in two experiments. A preliminary tumor cell dose titration study (Experiment 1) was designed to determine the inoculation dose to produce approximately 65% tumor incidence. Mice (n = 10/dose) were inoculated with 0 to 1 x 10(6) tumor cells in the right inguinal mammary fat pad. A tumor cell load of 2.5 x 10(3) cells/inoculation produced approximately 65% tumor incidence. This dose was used in a subsequent study (Experiment 2) of the efficacy of dietary lutein against mammary tumor development. Mice (n = 20/treatment) were fed a semisynthetic diet containing 0, 0.002, 0.02, 0.2 or 0.4% lutein from marigold extract. After 14 d, all mice were inoculated with 2.5 x 10(3) tumor cells, and tumor growth was measured daily for 70 d at which time blood, liver, spleen and tumors were obtained. Lutein + zeaxanthin uptake increased dose-dependently (P < 0.05) with dietary lutein levels from 0 to 0.02% (spleen) or 0.2% (plasma, liver and tumor). Low levels (0.002 and 0.02%) of dietary lutein lowered (P < 0.05) mammary tumor incidence, tumor growth and lipid peroxidation, and increased tumor latency, whereas higher dietary levels (0.2 or 0.4%) were less effective. Therefore, very low amounts of dietary lutein (0.002%) can efficiently decrease mammary tumor development and growth in mice.

Dietary lutein absorption from marigold extract is rapid in BALB/c mice

Even though lutein can stimulate immunity and decrease cancer growth, no systematic studies are available on the uptake of lutein in mice. We studied the uptake of lutein in 8-wk-old female BALB/c mice fed a diet containing 0, 0.05, 0.1, 0.2 or 0.4% lutein. Mice were killed on d 0, 3, 7, 14, 21 and 28 (n = 6/period), and blood, spleen and liver were collected. Food intake and body, liver and spleen weights did not differ among treatment groups. Lutein + zeaxanthin were not detectable in the plasma, liver and spleen of unsupplemented mice. Mice fed lutein showed very rapid lutein + zeaxanthin absorption. On d 3, concentrations of plasma lutein + zeaxanthin had rapidly increased (P < 0.05) in lutein-fed mice and no further increases were observed. Plasma lutein + zeaxanthin concentrations did not differ among lutein-fed mice by d 7 (2.58 +/- 0.2 micromol/L). Even though maximal uptake of plasma lutein + zeaxanthin was observed by d 3, uptake of lutein + zeaxanthin by the liver and especially by the spleen generally continued to increase (P < 0.05) through d 28 to reach concentrations of 0.11 +/- 0.001 (spleen) and 0.71 +/- 0. 0002 (liver) nmol/g. Therefore, dietary lutein is readily absorbed into the plasma and taken up by liver and spleen of mice. Plasma lutein + zeaxanthin concentrations were higher than in human studies; however, mice were fed lutein at a level several hundredfold greater than in humans. The liver is a major storage organ for lutein + zeaxanthin in mice. Uptake of lutein + zeaxanthin by the spleen suggests a role for lutein in modulating immunity.

Interactions between hormones and chemicals in breast cancer

Development of breast cancer in women is dependent on diverse factors, including genetic predisposition, exposure to both exogenous and endogenous chemicals, which can modulate initiation, promotion and progression of this disease, and the timing of exposure to these agents. Several compounds--including 16 alpha-hydroxyestrone (16 alpha-OHE1), catecholestrogens, and aromatic amines--have been proposed as initiators of mammary carcinogenesis in humans; however, their role as genotoxins is unconfirmed. Lifetime exposure to estrogens has been established as an important risk factor for breast cancer, and it has been suggested that xenoestrogens may directly add to the hormonal risk or indirectly increase risk by decreasing 2-hydroxyestrone (2-OHE1)/16 alpha-OHE1 metabolite ratios. Results of recent studies suggest that chemical-induced modulation of 2-OHE1/16 alpha-OHE1 metabolite ratios is not predictive of xenoestrogens or mammary carcinogens. Moreover, based on current known dietary intakes of natural and xenoestrogenic/antiestrogenic chemicals, it is unlikely that xenoestrogens contribute significantly to a woman's overall lifetime exposure to estrogens. More information is required on the identities and serum levels of both natural and xenoendocrine active compounds, their concentrations in serum, and the mammary gland and levels of these compounds at critical periods of exposure.

Dietary supplement use by women at risk for breast cancer recurrence. The Women's Healthy Eating and Living Study Group

OBJECTIVE

To develop a method of collecting, organizing, and analyzing information on nutrient and nonnutrient dietary supplement use by women at risk for breast cancer recurrence as a component of nutrition assessment and monitoring, and to describe the characteristics associated with dietary supplement use in this population at enrollment in a clinical trial to prevent breast cancer recurrence.

DESIGN

Cross-sectional descriptive study design.

SUBJECTS

Women diagnosed with breast cancer within the previous 4 years (n=435).

ANALYSIS

Dietary supplements reported in four 24-hour dietary recalls were categorized according to primary nutrient and nonnutrient contents. Prevalence of dietary supplement use is described. Associations between supplement use and demographic and participant characteristics were examined using chi(2) analysis and logistic regression.

RESULTS

Dietary supplement use was reported by 80.9% of the women. Increased likelihood of supplement use was associated with demographic (eg, older age, higher level of education, white race vs other ethnic groups) and personal (eg, lower body mass index, moderate alcohol consumption) characteristics. Use of vitamin C and related compounds, other nutrients (eg, n-3 fatty acids, evening primrose oil), and herbal products was inversely associated with months since diagnosis; use of miscellaneous supplements (eg, shark cartilage) was directly associated with more advanced stage at diagnosis.

APPLICATIONS

Monitoring dietary supplement use is an important aspect of nutrition assessment, especially in populations with chronic health conditions or medical diagnoses. Demographic and personal characteristics, time passed since diagnosis, and stage of cancer at diagnosis are predictive of dietary supplement use by women at risk for breast cancer recurrence. Associations in this population may be present in other groups that are the object of nutrition intervention efforts.