In vitro inhibition of proliferation of estrogen-dependent and estrogen-independent human breast cancer cells treated with carotenoids or retinoids

Association between dietary carotenoid intake and breast cancer risk: a case-control study among Korean women

The association between dietary carotenoids and breast cancer (BC) risks were inconsistent. Therefore, this study investigated the association between dietary carotenoid and BC risks among Korean women. We recruited participants from the National Cancer Centre of Korea. Odds ratios and 95% confidence intervals were calculated with a logistic regression model. There was an inverse association between dietary carotenoid subclasses and BC risks; in particular, a higher intake of β-carotene and lutein/zeaxanthin was associated with reduced BC risks. After subgroup analysis with estrogen receptor (ER)/progesterone receptor (PR) status, there was similar trend among ER-/PR- women. We further investigated which foods contribute to the carotenoid intake. A higher intake of radish leaves, kale, and bracken was associated with lowered BC risks. Accordingly, dietary carotenoid, particularly β-carotene and lutein/zeaxanthin, appears to be associated with a lower risk of BC among Korean women.

The Association between Circulating Carotenoids and Risk of Breast Cancer: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

Carotenoids appear to have anticancer effects. Prospective evidence for the relation between serum carotenoids and breast cancer is controversial. The present systematic review and meta-analysis aimed to investigate the link between circulating carotenoids and the risk of breast cancer. We performed a systematic search of PubMed, Scopus, and Web of Science up to 30 November, 2022. Prospective studies on adults aged ≥18 y that have reported risk estimates for the association between circulating carotenoids and breast cancer risk were considered. Study quality was assessed using the Newcastle-Ottawa Scale. A random-effects model was used for combining studies' risk estimates. Dose-response relations were explored through a 1-stage random-effects model. Fifteen publications (17 nested case-control studies and 1 cohort study) with 20,188 participants and 7608 cases were included. We observed an inverse association between the highest level of circulating total carotenoids (relative risk [RR]: 0.76; 95% confidence interval [CI]: 0.62, 0.93; n = 8), α-carotene (RR: 0.77; 95% CI: 0.68, 0.87; n = 13), β-carotene (RR: 0.80; 95% CI: 0.65, 0.98; n = 15), β-cryptoxanthin (RR: 0.85; 95% CI: 0.74, 0.96; n = 11), lycopene (RR: 0.86; 95% CI: 0.76, 0.98; n = 13), and lutein (RR: 0.70; 95% CI: 0.52, 0.93; n = 6) and the risk of breast cancer compared with the lowest level. Additionally, each 10 μg/dL of total carotenoids, α-carotene, β-carotene, and β-cryptoxanthin was associated with 2%, 22%, 4%, and 10% lower risk of breast cancer, respectively. This relationship was stronger at lower levels of total carotenoids and β-cryptoxanthin. The certainty of evidence was rated from very low to low. Most studies were performed among Western nations, which should be acknowledged for extrapolation of findings. Total circulating carotenoids, α-carotene, β-carotene, β-cryptoxanthin, lycopene, and lutein seem to be related to a decreased risk of breast cancer. Our findings could have practical importance for public health. This study was registered at PROSPERO as CRD42023434983.

Targeting nuclear hormone receptors for the prevention of breast cancer

Advancements in research have led to the steady decline of breast cancer mortality over the past thirty years. However, breast cancer incidence has continued to rise, resulting in an undue burden on healthcare costs and highlighting a great need for more effective breast cancer prevention strategies, including targeted chemo preventative agents. Efforts to understand the etiology of breast cancer have uncovered important roles for nuclear receptors in the development and progression of breast cancer. Targeted therapies to inhibit estrogen receptor (ER) and progesterone receptor (PR) signaling (selective ER modulators, aromatase inhibitors and selective PR modulators) have shown great promise for the treatment and prevention of hormone receptor (HR)-positive breast cancer. However, these drugs do not prevent HR-negative disease. Therefore, recent efforts have focused on novel targeted therapies with the potential to prevent both HR-positive and HR-negative breast cancer. Among these include drugs that target other nuclear receptors, such as retinoic acid receptor (RAR), retinoid X receptor (RXR) and vitamin D receptor (VDR). In this review we provide an overview of recent preclinical and clinical trials targeting members of the nuclear receptor superfamily for the prevention of breast cancer.

Anti-microbial, anti-oxidant, and anti-breast cancer properties unraveled in yeast carotenoids produced via cost-effective fermentation technique utilizing waste hydrolysate

Introduction

Natural carotenoids are well known for their anti-oxidant property and also shown to have antimicrobial and anticancer efficacy. Production of carotenoids from microbial resources mainly from yeast has attracted commercial interest. Breast cancer has the highest incidence among women, and therapy resistance and lack of effective therapeutic strategies are major treatment bottlenecks, particularly for triple-negative subtypes. Yeast carotenoids are recently being evaluated for affordable, non-toxic, natural product-based therapies. In the present study, we have shown an environment-friendly and inexpensive method for carotenoid production from yeasts, utilizing "mandi" wastes, and investigated the biomedical properties of carotenoids, particularly antineoplastic properties.

Methods

Vegetable "mandi" waste was used to prepare waste hydrolysate, a culture medium, in which oleaginous red yeast Rhodosporidium sp. was grown. Carotenoid pigments were extracted using the solvent extraction method and analyzed by UV spectroscopy, thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC). Antimicrobial, antioxidant, and anticancer activities of the extract were evaluated, followed by in silico docking and absorption, distribution, metabolism, and excretion/toxicity (ADME/T) studies.

Results

Carotenoid extract was found to be composed of three main pigments-β-carotene, torulene, and torularhodin. Extract exhibited significant antioxidant, antimicrobial, and anti-breast cancer activities in vitro while being biocompatible. Interestingly, carotenoids have shown better efficacy in triple-negative breast cancer (TNBC) cells than ER+PR+ cells. In silico evaluation predicted binding with breast cancer-specific molecular targets, specifically the three components showed good binding energy toward VEGF receptors and good drug likeliness properties, as well as less toxicity.

Discussion

This is the first report on anti-breast cancer activities, particularly targeting TNBC cells by red yeast carotenoids (β-carotene, torulene, and torularhodin) produced via a sustainable environment-friendly bioprocess utilizing waste hydrolysate.

Are dietary factors involved in the association of CDH4 methylation and breast cancer risk?

DNA methylation is one of the most important epigenetic modifications in breast cancer (BC) development, and long-term dietary habits can alter DNA methylation. Cadherin-4 (CDH4, a member of the cadherin family) encodes Ca²⁺-dependent cell-cell adhesion glycoproteins. We conducted a case-control study (380 newly diagnosed BC and 439 cancer-free controls) to explore the relationship of CDH4 methylation in peripheral blood leukocyte DNA (PBL DNA), as well as its combined and interactive effects with dietary factors on BC risk. A case-only study (335 newly diagnosed BC) was conducted to analyse the association between CDH4 methylation in breast tissue DNA and dietary factors. CDH4 methylation was detected using quantitative methylation-specific PCR. Unconditional logistic regressions were used to analyse the association of CDH4 methylation in PBL DNA and BC risk. Cross-over analysis and unconditional logistic regression were used to calculate the combined and interactive effects between CDH4 methylation in PBL DNA and dietary factors in BC. CDH4 hypermethylation was significantly associated with increased BC risk in PBL DNA (OR_adjusted (OR_adj) = 2·70, (95 % CI 1·90, 3·83), P < 0·001). CDH4 hypermethylation also showed significant combined effects with the consumption of vegetables (OR_adj = 4·33, (95 % CI 2·63, 7·10)), allium vegetables (OR_adj = 7·00, (95 % CI 4·17, 11·77)), fish (OR_adj = 7·92, (95 % CI 3·79, 16·53)), milk (OR_adj = 6·30, (95 % CI 3·41, 11·66)), overnight food (OR_adj = 4·63, (95 % CI 2·69, 7·99)), pork (OR_adj = 5·59, (95 % CI 2·94, 10·62)) and physical activity (OR_adj = 4·72, (95 % CI 2·87, 7·76)). Moreover, consuming milk was significantly related with decreased risk of CDH4 methylation (OR = 0·61, (95 % CI 0·38, 0·99)) in breast tissue. Our findings may provide direct guidance on the dietary intake for specific methylated carriers to decrease their risk for developing BC.

Tomatoes: An Extensive Review of the Associated Health Impacts of Tomatoes and Factors That Can Affect Their Cultivation

Simple Summary

The research outlined in this review paper discusses potential health benefits associated with a diet enriched with tomatoes and tomato products. This includes details of previous studies investigating the anticancer properties of tomatoes, protection against cardiovascular and neurodegenerative diseases and diabetes, maintenance of a healthy gut microbiome, and improved skin health, fertility, immune response, and exercise recovery. The specific parts of a tomato fruit that contribute these health benefits are also outlined. The potential disadvantages to a tomato-rich diet are detailed, especially the consumption of supplements that contain compounds found in tomatoes, such as lycopene. This review also discusses how the cultivation of tomato plants can affect the nutritional value of the fruit harvested. Different environmental growing conditions such as light intensity, growing media, and temperature are explained in terms of the impact they have on the quality of fruit, its nutrient content, and hence the potential health benefits acquired from eating the fruit.

Abstract

This review outlines the health benefits associated with the regular consumption of tomatoes and tomato products. The first section provides a detailed account of the horticultural techniques that can impact the quality of the fruit and its nutritional properties, including water availability, light intensity, temperature, and growing media. The next section provides information on the components of tomato that are likely to contribute to its health effects. The review then details some of the health benefits associated with tomato consumption, including anticancer properties, cardiovascular and neurodegenerative diseases and skin health. This review also discusses the impact tomatoes can have on the gut microbiome and associated health benefits, including reducing the risk of inflammatory bowel diseases. Other health benefits of eating tomatoes are also discussed in relation to effects on diabetes, the immune response, exercise recovery, and fertility. Finally, this review also addresses the negative effects that can occur as a result of overconsumption of tomato products and lycopene supplements.

An Updated Comprehensive Review on Vitamin A and Carotenoids in Breast Cancer: Mechanisms, Genetics, Assessment, Current Evidence, and Future Clinical Implications

Vitamin A and carotenoids are fat-soluble micronutrients that play important role as powerful antioxidants modulating oxidative stress and cancer development. Breast cancer is the most common malignancy in women. As the risk of breast cancer is dependent on various lifestyle factors such as dietary modifications, there is increasing interest surrounding the anti-cancerous properties of vitamin A and carotenoids. Despite the suggested protective roles of vitamin A and carotenoids in breast cancer development, their clinical application for the prevention and treatment of breast cancer is limited. In this narrative review, we discuss the roles of vitamin A and carotenoids along with the evaluation method of vitamin A status. We also exhibit the association of genetic variations involved in metabolism of vitamin A and carotenoids with cancers and other diseases. We demonstrate the epidemiological evidence for the relationship of vitamin A and carotenoids with breast cancer risk, their effects on cancer mechanism, and the recent updates in clinical practice of vitamin A or carotenoids as a potential therapeutic agent against breast cancer. This review provides insight into the preventive and therapeutic roles of vitamin A and carotenoids in breast cancer development and progression.

Dietary Vitamin A and Breast Cancer Risk in Black Women: The African American Breast Cancer Epidemiology and Risk (AMBER) Consortium

BACKGROUND

Studies in women of European descent showed an inverse association of dietary vitamin A (retinol and carotenoids) intake with breast cancer risks, mainly in premenopausal women.

OBJECTIVES

We examined whether higher compared with lower levels of dietary vitamin A are associated with reduced breast cancer risks among Black women by estrogen receptor (ER) and menopausal statuses.

METHODS

In this pooled analysis, data were from 3564 breast cancer cases and 11,843 controls (mean ages = 56.4 and 56.3 years, respectively) in the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. Dietary intake was assessed by FFQs. Multivariable logistic regressions were performed to estimate ORs and 95% CIs for study-specific quintiles of total vitamin A equivalents and individual carotenoids, and a pooled OR was estimated by a random-effect model.

RESULTS

We observed an inverse association of total vitamin A equivalents with ER-positive breast cancer (quintiles 5 compared with 1: pooled OR: 0.82; 95% CI: 0.67-1.00; P-trend = 0.045). The association was seen among premenopausal women (pooled OR: 0.60; 95% CI: 0.43-0.83; P-trend = 0.004), but not among postmenopausal women (pooled OR: 0.99; 95% CI: 0.77-1.28; P-trend = 0.78). Additionally, there were inverse associations of dietary β-carotene (quintiles 5 compared with 1: pooled OR: 0.70; 95% CI: 0.51-0.95; P-trend = 0.08) and lutein (pooled OR: 0.63; 95% CI: 0.45-0.87; P-trend = 0.020) with ER-positive breast cancer among premenopausal women. There was no evidence for an association of total vitamin A equivalents or individual carotenoids with ER-negative breast cancer, regardless of menopausal status.

CONCLUSIONS

Our findings on dietary vitamin A and breast cancer risks in Black women are consistent with observations in women of European descent and advance the literature showing an inverse association for ER-positive disease.

Carotenoids and Some Other Pigments from Fungi and Yeasts

Carotenoids are an essential group of compounds that may be obtained by microbiological synthesis. They are instrumental in various areas of industry, medicine, agriculture, and ecology. The increase of carotenoids' demand at the global market is now essential. At the moment, the production of natural carotenoids is more expensive than obtaining their synthetic forms, but several new approaches/directions on how to decrease this difference were developed during the last decades. This review briefly describes the information accumulated until now about the beneficial effects of carotenoids on human health protection, their possible application in the treatments of various diseases, and their use in the food and feed industry. This review also describes some issues that are linked with biotechnological production of fungal and yeasts carotenoids, as well as new approaches/directions to make their biotechnological production more efficient.

Breast cancer prevention in premenopausal women: role of the Mediterranean diet and its components

Breast cancer (BC) is a growing public health concern in most developed and developing countries. Since an increasing number of patients with BC are diagnosed before the menopause and premenopausal women show a more aggressive phenotype, there is consistent interest in promoting prevention strategies in order to reduce the incidence of BC in the premenopause. The Mediterranean diet (MD) has been reported to have beneficial effect in terms of cancer prevention. This healthy dietary pattern consists primarily of foods having important antioxidant properties along with a favourable fatty acid profile, all associated with a reduced risk of cancer. Due to the large variability in study subject characteristics, the protective role of the MD on BC still remains controversial and studies that have investigated the association between adherence to the MD and risk of BC in premenopausal women are fewer than those in postmenopausal women. In addition, the possibility that the beneficial effects of the MD are due to a single component or might more probably derive from the synergic effects of all components of the MD remains a scantly explored field. Considering the increased risk of recurrence and mortality rate of BC in premenopausal women as compared with postmenopausal women, the aim of the present report is to provide a general overview of the current evidence on the relationship between BC and the MD specifically in premenopausal women, and to emphasise the potential role of the MD as an effective measure to reduce the risk of developing BC in premenopausal women.

Comparative Analysis of Lycopene Content from Different Tomato-Based Food Products on the Cellular Activity of Prostate Cancer Cell Lines

Lycopene is more bioavailable in processed tomato products than in raw tomatoes, since arrangement of cis-isomers of lycopene during food processing and storage may increase its biological activity. The aim of the study is evaluate the influence of lycopene content from different tomato-based food products (extract, paste, ketchup and sauce) on cell proliferation, cell cycle, and rate of apoptosis of human prostate cancer cell lines. DU-145 and PC-3 cell lines were treated with lycopene content from different tomato-based food products (500-5000 μg/mL) for 96 h. The data showed a decrease in cell viability in both DU-145 and PC-3 cells after treatment with all lycopene extracts from tomato-based food products. Analysis of cell cycle revealed a decrease in the percentage of prostate cancer cells in G0/G1 and G2/M phases after 96 h of treatment when using lycopene content from tomato paste and tomato extract. However, lycopene extracted from tomato sauce and ketchup promoted a decrease in the percentage of cells in G0/G1 phase and an increase in S and G2/M phases after 96 h of treatment. Lycopene content from all of those tomato-based food products also increased apoptosis in both prostate cancer cell lines. In this regard, lycopene has proved to be a potent inhibitor of cell viability, arrest cell cycle and increase the apoptosis in human prostate cancer cells, suggesting an effect in the balance of human prostate cancer cell lines growth.

Bioactivities of phytochemicals present in tomato

Tomato is a wonder fruit fortified with health-promoting phytochemicals that are beneficial in preventing important chronic degenerative disorders. Tomato is a good source of phenolic compounds (phenolic acids and flavonoids), carotenoids (lycopene, α, and β carotene), vitamins (ascorbic acid and vitamin A) and glycoalkaloids (tomatine). Bioactive constituents present in tomato have antioxidant, anti-mutagenic, anti-proliferative, anti-inflammatory and anti-atherogenic activities. Health promoting bioactivities of tomatoes make them useful ingredient for the development of functional foods. Protective role of tomato (lycopene as a potent antioxidant) in humans against various degenerative diseases are known throughout the world. Intake of tomato is inversely related to the incidence of cancer, cardiovascular diseases, ageing and many other health problems. Bioavailability of phytoconstituents in tomato is generally not affected by routine cooking processes making it even more beneficial for human consumption. The present review provides collective information of phytochemicals in tomato along with discussing their bioactivities and possible health benefits.

ROS production and glutathione response in keratinocytes after application of β-carotene and VIS/NIR irradiation

The skin is exposed to many stress factors which, in turn, can promote a shift of the antioxidant (AO) network towards the prooxidative side, supporting the development of various skin disorders. A balanced diet, in combination with a healthy lifestyle could reduce oxidative stress. Carotenoids are essential nonenzymatic AOs and main components of the exogenous AO system. To examine the interdependence between endogenous and exogenous AOs, secondary keratinocytes (HaCaT) were treated with various Beta (β-)-carotene concentrations with subsequent stress treatment by moderate irradiation (700-2000 nm). To facilitate the uptake of β-carotene, an innovative nanocrystal solution was used. Cell viability assay was applied to HaCaT cells to evaluate suitable concentration of β-carotene, whereby the uptake was measured by resonant Raman spectroscopy. The redox status was determined before and after supplementation with two selected β-carotene concentrations (0.02 and 0.1 μg/ml) and irradiation. Reactive oxygen species (ROS) were measured by electron paramagnetic resonance spectroscopy and the AO glutathione (GSH) by a fluorescent-based assay for evaluating the endogenous redox status. An increase of ROS and a reduction of GSH after irradiation was observed. Interestingly, the applied β-carotene, already induce oxidative stress. Nevertheless, an effective protection against irradiation could be observed for the lower dose. The high dose turned pro-oxidative.

Plasma carotenoids and the risk of premalignant breast disease in women aged 50 and younger: a nested case-control study

PURPOSE

To examine the association of plasma carotenoids, micronutrients in fruits, and vegetables, with risk of premalignant breast disease (PBD) in younger women.

METHODS

Blood samples were collected at the Siteman Cancer Center between 2008 and 2012 from 3537 women aged 50 or younger with no history of cancer or PBD. The analysis included 147 participants diagnosed with benign breast disease or breast carcinoma in situ during a 27-month follow-up and 293 controls. Cases and controls were matched on age, race/ethnicity, and date of and fasting status at blood draw. Plasma carotenoids were quantified. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) and linear regression to assess racial differences in plasma carotenoids.

RESULTS

The risk reduction between the highest and lowest tertiles varied by carotenoid, with β-cryptoxanthin having the greatest reduction (OR 0.62; 95% CI, 0.62-1.09; P _trend = 0.056) and total carotenoids the least (OR 0.83; 95% CI, 0.48-1.44; P _trend = 0.12). We observed an inverse association between plasma carotenoids and risk of PBD in obese women (BMI ≥ 30 kg/m²; 61 cases and 115 controls) but not lean women (BMI < 25 kg/m²; 54 cases and 79 controls), although the interaction was not statistically significant. Compared to white women, black women had lower levels of α and β-carotene and higher levels of β-cryptoxanthin and lutein/zeaxanthin.

CONCLUSIONS

We observed suggestive inverse associations between plasma carotenoids and risk of PBD in younger women, consistent with inverse associations reported for invasive breast cancer. Carotenoids may play a role early in breast cancer development.

Lycopene acts through inhibition of IκB kinase to suppress NF-κB signaling in human prostate and breast cancer cells

We studied the effect of the potent dietary antioxidant lycopene on multiple points along the nuclear factor kappa B (NF-κB) signaling pathway in prostate and breast cancer cells. Lycopene significantly inhibited prostate and breast cancer cell growth at physiologically relevant concentrations of ≥1.25 μM. Similar concentrations also caused a 30-40 % reduction in inhibitor of kappa B (IκB) phosphorylation in the cells, as determined by western blotting. Furthermore, the same degree of inhibition by lycopene was observed for NF-κB transcriptional activity, as determined by reporter gene assay. Concomitant with this, immunofluorescence staining of lycopene-treated cells showed a significant suppression (≥25 %) of TNF-induced NF-κB p65 subunit nuclear translocation. Further probing of lycopene's effects on upstream elements of the NF-κB pathway showed a 25 % inhibition of both activity of recombinant IκB kinase β (IKKβ) kinase in a cell-free in vitro assay, as well as activity of IKKβ immunoprecipitated from MDA-MB-231 cells treated with lycopene. In conclusion, the anticancer properties of lycopene may occur through inhibition of the NF-κB signaling pathway, beginning at the early stage of cytoplasmic IKK kinase activity, which then leads to reduced NF-κB-responsive gene regulation. Furthermore, these effects in cancer cells were observed at concentrations of lycopene that are relevant and achievable in vivo.

Estrogenic endocrine disruptors: Molecular mechanisms of action

A comprehensive summary of more than 450 estrogenic chemicals including estrogenic endocrine disruptors is provided here to understand the complex and profound impact of estrogen action. First, estrogenic chemicals are categorized by structure as well as their applications, usage and effects. Second, estrogenic signaling is examined by the molecular mechanism based on the receptors, signaling pathways, crosstalk/bypassing and autocrine/paracrine/homeostatic networks involved in the signaling. Third, evaluation of estrogen action is discussed by focusing on the technologies and protocols of the assays for assessing estrogenicity. Understanding the molecular mechanisms of estrogen action is important to assess the action of endocrine disruptors and will be used for risk management based on pathway-based toxicity testing.

Relationship between Carotenoids, Retinol, and Estradiol Levels in Older Women

BACKGROUND

In vitro evidence suggests anti-estrogenic properties for retinol and carotenoids, supporting a chemo-preventive role of these phytochemicals in estrogen-dependent cancers. During aging there are significant reductions in retinol and carotenoid concentrations, whereas estradiol levels decline during menopause and progressively increase from the age of 65. We aimed to investigate the hypothesis of a potential relationship between circulating levels of retinol, carotenoids, and estradiol (E2) in a cohort of late post-menopausal women.

METHODS

We examined 512 women ≥ 65 years from the InCHIANTI study. Retinol, α-caroten, β-caroten, β-criptoxantin, lutein, zeaxanthin, and lycopene levels were assayed at enrollment (1998-2000) by High-Performance Liquid Chromatography. Estradiol and testosterone (T) levels were assessed by Radioimmunometry (RIA) and testosterone-to-estradiol ratio (T/E2), as a proxy of aromatase activity, was also calculated. General linear models adjusted for age (Model 1) and further adjusted for other confounders including Body Mass Index (BMI) BMI, smoking, intake of energy, lipids, and vitamin A; C-Reactive Protein, insulin, total cholesterol, liver function, and testosterone (Model 2) were used to investigate the relationship between retinol, carotenoids, and E2 levels. To address the independent relationship between carotenoids and E2 levels, factors significantly associated with E2 in Model 2 were also included in a fully adjusted Model 3.

RESULTS

After adjustment for age, α-carotene (β ± SE = -0.01 ± 0.004, p = 0.02) and β-carotene (β ± SE = -0.07 ± 0.02, p = 0.0007) were significantly and inversely associated with E2 levels. α-Carotene was also significantly and positively associated with T/E2 ratio (β ± SE = 0.07 ± 0.03, p = 0.01). After adjustment for other confounders (Model 2), the inverse relationship between α-carotene (β ± SE = -1.59 ± 0.61, p = 0.01), β-carotene (β ± SE = -0.29 ± 0.08, p = 0.0009), and E2 persisted whereas the relationship between α-carotene and T/E2 ratio was attenuated (β ± SE = 0.22 ± 0.12, p = 0.07). In a fully adjusted model (Model 3), only β-carotene (β ± SE = -0.05 ± 0.02, p = 0.03) was significantly and inversely associated with E2 levels independent of α-carotene. No association was found between retinol, total non-pro-vitamin A carotenoids, lutein, zeaxanthin, and lycopene, and E2 levels.

CONCLUSIONS

In older women, β-carotene levels are independently and inversely associated with E2.

Plasma carotenoids and risk of breast cancer over 20 y of follow-up

BACKGROUND

Increasing evidence suggests that carotenoids, which are micronutrients in fruit and vegetables, reduce breast cancer risk. Whether carotenoids are important early or late in carcinogenesis is unclear, and limited analyses have been conducted by breast tumor subtypes.

OBJECTIVES

We sought to examine issues of the timing of carotenoid exposure as well as associations by breast tumor subtypes.

DESIGN

We conducted a nested case-control study of plasma carotenoids measured by using reverse-phase high-performance liquid chromatography and breast cancer risk in the Nurses' Health Study. In 1989-1990, 32,826 women donated blood samples; in 2000-2002, 18,743 of these women contributed a second blood sample. Between the first blood collection and June 2010, 2188 breast cancer cases were diagnosed (579 cases were diagnosed after the second collection) and matched with control subjects. RRs and 95% CIs were calculated by using conditional logistic regression adjusted for several breast cancer risk factors.

RESULTS

Higher concentrations of α-carotene, β-carotene, lycopene, and total carotenoids were associated with 18-28% statistically significantly lower risks of breast cancer (e.g., β-carotene top compared with bottom quintile RR: 0.72; 95% CI: 0.59, 0.88; P-trend < 0.001). Associations were apparent for total carotenoids measured ≥10 y before diagnosis (top compared with bottom quintile RR: 0.69; 95% CI: 0.50, 0.95; P-trend = 0.01) as well as those <10 y before diagnosis (RR: 0.79; 95% CI: 0.64, 0.98; P-trend = 0.04, P-interaction = 0.11). Carotenoid concentrations were strongly inversely associated with breast cancer recurrence and death (e.g., β-carotene top compared with bottom quintile RR: 0.32; 95% CI: 0.21, 0.51; P-trend < 0.001) compared with not recurrent and not lethal disease (P-heterogeneity < 0.001).

CONCLUSION

In this large prospective analysis with 20 y of follow-up, women with high plasma carotenoids were at reduced breast cancer risk particularly for more aggressive and ultimately fatal disease.

MicroRNA-10a is reduced in breast cancer and regulated in part through retinoic acid

Background

MicroRNAs (miRNAs) are short non-coding RNA molecules that play a critical role in mRNA cleavage and translational repression, and are known to be altered in many diseases including breast cancer. MicroRNA-10a (miR-10a) has been shown to be deregulated in various cancer types. The aim of this study was to investigate miR-10a expression in breast cancer and to further delineate the role of retinoids and thyroxine in regulation of miR-10a.

Methods

Following informed patient consent and ethical approval, tissue samples were obtained during surgery. miR-10a was quantified in malignant (n = 103), normal (n = 30) and fibroadenoma (n = 35) tissues by RQ-PCR. Gene expression of Retinoic Acid Receptor beta (RARβ) and Thyroid Hormone receptor alpha (THRα) was also quantified in the same patient samples (n = 168). The in vitro effects of all-trans Retinoic acid (ATRA) and L-Thyroxine (T₄) both individually and in combination, on miR-10a expression was investigated in breast cancer cell lines, T47D and SK-BR-3.

Results

The level of miR-10a expression was significantly decreased in tissues harvested from breast cancer patients (Mean (SEM) 2.1(0.07)) Log₁₀ Relative Quantity (RQ)) compared to both normal (3.0(0.16) Log₁₀ RQ, p < 0.001) and benign tissues (2.6(0.17) Log₁₀ RQ, p < 0.05). The levels of both RARβ and THRα gene expression were also found to be decreased in breast cancer patients compared to controls (p < 0.001). A significant positive correlation was determined between miR-10a and RARβ (r = 0.31, p < 0.001) and also with THRα (r = 0.32, p < 0.001). In vitro stimulation assays revealed miR-10a expression was increased in both T47D and SK-BR-3 cells following addition of ATRA (2 fold (0.7)). While T₄ alone did not stimulate miR-10a expression, the combination of T₄ and ATRA was found to have a positive synergistic effect.

Conclusion

The data presented supports a potential tumour suppressor role for miR-10a in breast cancer, and highlights retinoic acid as a positive regulator of the microRNA.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1374-y) contains supplementary material, which is available to authorized users.

Interplay between estrogen and retinoid signaling in breast cancer--current and future perspectives

All-trans-retinoic acid (RA) is a promising agent for breast cancer treatment, but it induces several adverse effects and the few clinical trials performed up to now in breast cancer patients have provided disappointing results. The combination of RA and antiestrogenic compounds, such as tamoxifen, synergistically decreases the proliferation of breast cancer cells and an interplay between retinoid and estrogen signaling has begun to be unraveled, turning these combinations into an appealing strategy for breast cancer treatment. This review focus on the current knowledge regarding the interplay between retinoid and estrogen signaling in breast cancer and the combinations of RA with antiestrogens, aiming their future utilization in cancer therapy.

Certain carotenoids enhance the intracellular glutathione level in a murine cultured macrophage cell line by inducing glutamate-cysteine-ligase

SCOPE

Glutathione (GSH) increases in RAW264 murine macrophage cells exposed to β-carotene or β-cryptoxanthin, however, the underlying mechanism has not been clarified. In the present study, we investigated the expression of glutamate-cysteine-ligase (GCL), the rate-limiting enzyme in GSH synthesis, in these cells.

METHODS AND RESULTS

Both the protein and mRNA expression of GCL increased in a β-carotene concentration-dependent manner. Buthionine sulfoximine, a GCL inhibitor, abolished the β-carotene-induced GSH increase without affecting the β-carotene-induced GCL protein expression. Both cycloheximide, a translation inhibitor, and actinomycin D, a transcription inhibitor, completely suppressed the β-carotene-induced GCL protein expression and the concomitant GSH increase. Actinomycin D inhibited the β-carotene-induced Gcl mRNA expression as well. Similarly to β-carotene, β-cryptoxanthin upregulated the GCL protein expression, but lutein did not. The c-Jun N-terminal kinase (JNK) inhibitor, SP600125, suppressed the β-carotene-induced GSH increase, whereas a p38 mitogen-activated protein kinase inhibitor or an extracellular signal-regulated kinase 1/2 inhibitor did not. The JNK inhibitor also suppressed the β-carotene-induced GCL protein expression, and consistently β-carotene induced JNK phosphorylation.

CONCLUSION

These findings revealed that certain carotenoids induce the Gcl mRNA expression in RAW264 cells and subsequently the GCL protein expression, which concomitantly enhances the intracellular GSH level, in a JNK pathway-related manner.

Effects of tomato and soy on serum adipokine concentrations in postmenopausal women at increased breast cancer risk: a cross-over dietary intervention trial

CONTEXT

Breast cancer risk among postmenopausal women increases as body mass index increases. Practical preventive methods to reduce risk of breast cancer are lacking. Few studies have investigated the effects of carotenoids and isoflavones on circulating adipokines in postmenopausal women.

OBJECTIVE

The aim was to examine the effects of lycopene- and isoflavone-rich diets on serum adipokines.

DESIGN

This was a 26-week, two-arm, longitudinal crossover trial.

SETTING

Participants were recruited from clinics at The Ohio State University Comprehensive Cancer Center.

PARTICIPANTS

Seventy postmenopausal women at increased breast cancer risk participated in the study. The mean age and body mass index of participants was 57.2 years and 30.0 kg/m(2), respectively; the study was comprised of 81.4% whites.

INTERVENTIONS

The interventions included 10 weeks of consumption of a tomato-based diet (≥25 mg lycopene daily) and 10 weeks of consumption of a soy-based diet (≥40 g of soy protein daily), with a 2-week washout in between.

MAIN OUTCOME MEASURES

Changes in serum adiponectin, leptin, and the adiponectin to leptin ratio were examined for each intervention through linear mixed models, with ratio estimates corresponding to postintervention adipokine concentrations relative to preintervention concentrations.

RESULTS

After the tomato intervention, among all women, adiponectin concentration increased (ratio 1.09, 95% confidence interval (CI) 1.00-1.18), with a stronger effect observed among nonobese women (ratio 1.13, 95% CI 1.02-1.25). After the soy intervention, adiponectin decreased overall (ratio 0.91, 95% CI 0.84-0.97), with a larger reduction observed among nonobese women (ratio 0.89, 95% CI 0.81-0.98). Overall, no significant changes in leptin or the adiponectin to leptin ratio were observed after either intervention.

CONCLUSIONS

Increasing dietary consumption of tomato-based foods may beneficially increase serum adiponectin concentrations among postmenopausal women at increased breast cancer risk, especially those who are not obese. Additional studies are essential to confirm these effects and to elucidate the specific mechanisms that may make phytonutrients found in tomatoes practical as breast cancer chemopreventive agents.

Circulating carotenoids and risk of breast cancer: pooled analysis of eight prospective studies

BACKGROUND

Carotenoids, micronutrients in fruits and vegetables, may reduce breast cancer risk. Most, but not all, past studies of circulating carotenoids and breast cancer have found an inverse association with at least one carotenoid, although the specific carotenoid has varied across studies.

METHODS

We conducted a pooled analysis of eight cohort studies comprising more than 80% of the world's published prospective data on plasma or serum carotenoids and breast cancer, including 3055 case subjects and 3956 matched control subjects. To account for laboratory differences and examine population differences across studies, we recalibrated participant carotenoid levels to a common standard by reassaying 20 plasma or serum samples from each cohort together at the same laboratory. Using conditional logistic regression, adjusting for several breast cancer risk factors, we calculated relative risks (RRs) and 95% confidence intervals (CIs) using quintiles defined among the control subjects from all studies. All P values are two-sided.

RESULTS

Statistically significant inverse associations with breast cancer were observed for α-carotene (top vs bottom quintile RR = 0.87, 95% CI = 0.71 to 1.05, P(trend) = .04), β-carotene (RR = 0.83, 95% CI = 0.70 to 0.98, P(trend) = .02), lutein+zeaxanthin (RR = 0.84, 95% CI = 0.70 to 1.01, P(trend) = .05), lycopene (RR = 0.78, 95% CI = 0.62 to 0.99, P(trend) = .02), and total carotenoids (RR = 0.81, 95% CI = 0.68 to 0.96, P(trend) = .01). β-Cryptoxanthin was not statistically significantly associated with risk. Tests for heterogeneity across studies were not statistically significant. For several carotenoids, associations appeared stronger for estrogen receptor negative (ER(-)) than for ER(+) tumors (eg, β-carotene: ER(-): top vs bottom quintile RR = 0.52, 95% CI = 0.36 to 0.77, P(trend) = .001; ER(+): RR = 0.83, 95% CI = 0.66 to 1.04, P(trend) = .06; P(heterogeneity) = .01).

CONCLUSIONS

This comprehensive prospective analysis suggests women with higher circulating levels of α-carotene, β-carotene, lutein+zeaxanthin, lycopene, and total carotenoids may be at reduced risk of breast cancer.

The role of lycopene and its derivatives in the regulation of transcription systems: implications for cancer prevention

Evidence from epidemiologic studies has suggested that carotenoids, and lycopene in particular, decrease the risk of cancer: however, not all studies support this view. To gain insight into the molecular mechanisms whereby lycopene and other carotenoids may exert their chemoprotective effects, we and others performed a series of studies that used a large panel of cancer cell lines of different lineages and animal models of human cancer. In this review we address some of the mechanisms proposed for the cancer-preventive activity of tomato lycopene, focusing on the induction of the antioxidant response element transcription system and the inhibition of the transcriptional activity of sex hormones, such as estrogens and androgens, and the activity of growth factors, such as insulin-like growth factor. We also considered the modulation by lycopene of the transcription factors peroxisome proliferator-activated receptor, retinoid X receptor, liver X receptor, and activating protein-1. The ligands and the phytonutrient regulators of these transcription systems contain electrophilic active groups, whereas lycopene and nonxanthophylic carotenoids are devoid of them. Thus, we suggest that at least some of the cellular effects of carotenoids are mediated through their derivatives formed either by chemical oxidation or by enzymatic cleavage inside the cells. This review highlights findings that pertain to this exciting avenue of research, which is currently under intense scrutiny in several laboratories worldwide.

Effect of lycopene on cell viability and cell cycle progression in human cancer cell lines

BACKGROUND

Lycopene, a major carotenoid component of tomato, has a potential anticancer activity in many types of cancer. Epidemiological and clinical trials rarely provide evidence for mechanisms of the compound's action, and studies on its effect on cancer of different cell origins are now being done. The aim of the present study was to determine the effect of lycopene on cell cycle and cell viability in eight human cancer cell lines.

METHODS

Human cell lines were treated with lycopene (1-5 μM) for 48 and 96 h. Cell viability was monitored using the method of MTT. The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick labeling (TUNEL) and by DAPI.

RESULTS

Our data showed a significant decrease in the number of viable cells in three cancer cells lines (HT-29, T84 and MCF-7) after 48 h treatment with lycopene, and changes in the fraction of cells retained in different cell cycle phases. Lycopene promoted also cell cycle arrest followed by decreased cell viability in majority of cell lines after 96 h, as compared to controls. Furthermore, an increase in apoptosis was observed in four cell lines (T-84, HT-29, MCF-7 and DU145) when cells were treated with lycopene.

CONCLUSIONS

Our findings show the capacity of lycopene to inhibit cell proliferation, arrest cell cycle in different phases and increase apoptosis, mainly in breast, colon and prostate lines after 96 h. These observations suggest that lycopene may alter cell cycle regulatory proteins depending on the type of cancer and the dose of lycopene administration. Taken together, these data indicated that the antiproliferative effect of lycopene was cellular type, time and dose-dependent.

Selective inhibition of cell proliferation by lycopene in MCF-7 breast cancer cells in vitro: a proteomic analysis

Lycopene, a red pigmented carotenoid present in many fruits and vegetables such as tomatoes, has been associated with the reduced risk of breast cancer. This study sought to identify proteins modulated by lycopene during cell proliferation of the breast cancer cell line MCF-7 to gain an understanding into its mechanism of action. MCF-7 breast cancer cells and MCF-10 normal breast cells were treated with 0, 2, 4, 6, 8, and 10 μM of lycopene for 72 h. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tetrazolium reduction assay was used to measure cell proliferation and two-dimensional fluorescence difference gel electrophoresis to assess the changes in protein expression, which were identified using MALDI-ToF/ToF (matrix-assisted laser desorption ionization tandem time-of-flight) and Mascot database search. MTT and cell proliferation assays showed that lycopene selectively inhibited the growth of MCF-7 but not MCF-10 cells. Difference gel electrophoresis analysis revealed that proteins in the MCF-7 cells respond differently to lycopene compared with the MCF-10 cells. Lycopene altered the expression levels of proteins such as Cytokeratin 8/18 (CK8/18), CK19 and their post translational status. We have shown that lycopene inhibits cell proliferation in MCF-7 human breast cancer cells but not in the MCF-10 mammary epithelial cells. Lycopene was shown to modulate cell cycle proteins such as beta tubulin, CK8/18, CK19 and heat shock proteins.

Anti-tumor effects of all-trans retinoic acid are enhanced by genistein

The effects of all-trans retinoic acid (ATRA) on cancer are complex. ATRA has anti-cancer effects as it promotes cancer cell differentiation. However, ATRA also up-regulates expression of vascular endothelial growth factor (VEGF) in cancer cells, which leads to angiogenesis and can, thus, facilitate cancer growth. Genistein, a crucial non-nutrient component in soybean, exhibits anti-cancer effects by inhibiting protein tyrosine kinase that is involved in up-regulation of VEGF. We hypothesized that genistein, applied simultaneously with ATRA, would counter its undesired angiogenic effects and, thus, enhance the anti-cancer effects of ATRA. The purpose of this study was to document potential synergistic effects of genistein and ATRA in A549 lung adenocarcinoma cells. We further explored the role of genistein on countering the ATRA-induced VEGF expression. We demonstrate that genistein enhances the ATRA-induced growth inhibition of A549 cells by promoting apoptosis. Further, the combined use of ATRA and genistein leads to cancer cell arrest in G0/G1 and G2/M cell cycle phases. Finally, expression of VEGF (both mRNA and protein) was diminished in A549 cells exposed to both ATRA and genistein. In conclusion, our results demonstrate that genistein effectively enhances anti-cancer effects of ATRA, particularly, by countering the ATRA-induced up-regulation of VEGF. Our study provides an experimental basis for combined use of ATRA and genistein in the treatment of lung cancer.

Carotenoid intakes and risk of breast cancer defined by estrogen receptor and progesterone receptor status: a pooled analysis of 18 prospective cohort studies

BACKGROUND

Epidemiologic studies examining associations between carotenoid intakes and risk of breast cancer by estrogen receptor (ER) and progesterone receptor (PR) status are limited.

OBJECTIVE

We investigated these associations in a pooled analysis of 18 cohort studies.

DESIGN

Of 1,028,438 participants followed for a maximum follow-up of 26 y across studies, 33,380 incident invasive breast cancers were identified. Study-specific RRs and 95% CIs were estimated by using Cox proportional hazards regression and then pooled by using a random-effects model.

RESULTS

α-Carotene, β-carotene, and lutein/zeaxanthin intakes were inversely associated with the risk of ER-negative (ER-) breast cancer (pooled multivariable RRs of the comparison between the highest and lowest quintiles): α-carotene (0.87; 95% CI: 0.78, 0.97), β-carotene (0.84; 95% CI: 0.77, 0.93), and lutein/zeaxanthin (0.87; 95% CI: 0.79, 0.95). These variables were not inversely associated with the risk of ER-positive (ER+) breast cancer (pooled multivariable RRs for the same comparison): α-carotene (1.04; 95% CI: 0.99, 1.09), β-carotene (1.04; 95% CI: 0.98, 1.10), and lutein/zeaxanthin (1.00; 95% CI: 0.93, 1.07). Although the pooled RRs for quintile 5 for β-cryptoxanthin were not significant, inverse trends were observed for ER- and ER+ breast cancer (P-trend ≤ 0.05). Nonsignificant associations were observed for lycopene intake. The associations were largely not appreciably modified by several breast cancer risk factors. Nonsignificant associations were observed for PR-positive and PR-negative breast cancer.

CONCLUSIONS

Intakes of α-carotene, β-carotene, and lutein/zeaxanthin were inversely associated with risk of ER-, but not ER+, breast cancer. However, the results need to be interpreted with caution because it is unclear whether the observed association is real or due to other constituents in the same food sources.

Effects of lycopene and apigenin on human umbilical vein endothelial cells in vitro under angiogenic stimulation

Angiogenesis is the formation process of new blood vessels from preexisting vessels. Solid tumors need angiogenesis for growth and metastasis. The suppression of tumor growth by inhibition of neoangiogenic processes represents a potential approach to cancer treatment. Lycopene has powerful antioxidant capacities and anticarcinogenic properties. The aim of this study was to investigate the effects of lycopene on angiogenesis in vitro. For this reason, we measured in vitro angiogenesis in human umbilical vein endothelial cells including parameters of cell proliferation, tube formation, cell migration. Lycopene and apigenin were observed to block the endothelial cell proliferation in a dose-dependent manner. In addition, they significantly decreased the capillary-like tube lengths, tube formation and endothelial cell migration. This study provides indications that apigenin and lycopene, which are considered as chemopreventive agents, to be effective in vitro on endothelial cells and angiogenesis.

Effects of a carrot juice intervention on plasma carotenoids, oxidative stress, and inflammation in overweight breast cancer survivors

Evidence suggests that higher plasma carotenoid concentrations are protective in relation to breast cancer recurrence. This simple randomized carrot juice intervention study was designed to test the hypothesis that daily intake of 8 ounces of fresh BetaSweet (anthocyanin-rich) or Balero orange carrot juice would increase plasma total carotenoid concentrations to levels previously shown to be associated with reduced breast cancer recurrence. It was hypothesized that regular carrot juice intake would be associated with reductions in oxidative stress (8-iso-PGF2α) and inflammation (thromboxane B2, prostaglandin E2 metabolites, and hsC-reactive protein). Sixty-nine overweight breast cancer survivors consumed fresh carrot juice made from study-provided carrots for 3 wk. Total plasma carotenoids increased by 1.65 and 1.38 umol/L for the BetaSweet and Balero carrot juice, respectively. Rise in total plasma carotenoids for the overall sample was inversely associated with 8-iso-PGFα (OR: 0.13; 95% CI: 0.20 to 0.75; no differences were shown by carrot variety. These results suggest daily intake of fresh carrot juice is a simple and effective approach to increasing plasma total carotenoids and in turn reducing oxidative stress, but not inflammatory markers, in women previously treated for breast cancer.

Effects of tomato- and soy-rich diets on the IGF-I hormonal network: a crossover study of postmenopausal women at high risk for breast cancer

To determine whether dietary modifications with tomato products and/or a soy supplement affected circulating levels of insulin-like growth factor (IGF)-1 and other markers of cell signaling in postmenopausal women at risk for developing breast cancer. Eligible and consented postmenopausal women at high risk for developing breast cancer were enrolled in a 26-week, two-arm (tomato and soy, 10 weeks each) longitudinal dietary intervention study in which each woman served as her own control. Changes in biochemical endpoints including IGF-I, IGF-binding protein (IGFBP)-3, estradiol, sex hormone-binding globulin (SHBG), C-peptide, and insulin were measured for each intervention arm. Carotenoid and isoflavone levels were measured to assess adherence. Significant increases in carotenoid and isoflavone levels during the tomato and soy study arms, respectively, suggested that women were adherent to both arms of the intervention. The tomato-rich diet had little effect on cell-signaling biomarkers previously associated with breast cancer risk. However, results of the soy intervention showed that concentrations of IGF-I and IGFBP-3 increased by 21.6 and 154.7 μmol/L, respectively (P = 0.001 for both) and SHBG decreased by 5.4 μmol/L (P < 0.001) after consumption of the soy protein supplement. Increased soy protein intake may lead to small, but significant, increases in IGF-I and IGFBP-3. Soy consumption also led to a significant decrease in SHBG, which has been hypothesized to promote, rather than prevent, cancer growth. Previous epidemiologic studies, however, have confirmed protective effect of soy on breast cancer. Additional investigation about the effect of soy on breast cancer risk and its mechanism of action is warranted.

Chemistry and biotechnology of carotenoids

Carotenoids are one of the most widespread groups of pigments in nature and more than 600 of these have been identified. Beside provitamin A activity, carotenoids are important as antioxidants and protective agents against various diseases. They are isoprenoids with a long polyene chain containing 3 to 15 conjugated double bonds, which determines their absorption spectrum. Cyclization at one or both ends occurs in hydrocarbon carotene, while xanthophylls are formed by the introduction of oxygen. In addition, modifications involving chain elongation, isomerization, or degradation are also found. The composition of carotenoids in food may vary depending upon production practices, post-harvest handling, processing, and storage. In higher plants they are synthesized in the plastid. Both mevalonate dependent and independent pathway for the formation of isopentenyl diphosphate are known. Isopentenyl diphosphate undergoes a series of addition and condensation reactions to form phytoene, which gets converted to lycopene. Cyclization of lycopene either leads to the formation of β-carotene and its derivative xanthophylls, β-cryptoxanthin, zeaxanthin, antheraxanthin, and violaxanthin or α-carotene and lutein. Even though most of the carotenoid biosynthetic genes have been cloned and identified, some aspects of carotenoid formation and manipulation in higher plants especially remain poorly understood. In order to enhance the carotenoid content of crop plants to a level that will be required for the prevention of diseases, there is a need for research in both the basic and the applied aspects.

Effects of ascorbic acid and β-carotene on HepG2 human hepatocellular carcinoma cell line

Recent studies have demonstrated that vegetable rich diets have protective effects on the occurrence and prognosis of various cancers. In addition to dietary intakes, ascorbic acid and β-carotene are also taken as supplements. The aim of this study was to assess effects of ascorbic acid, β-carotene and their combinations on human hepatocellular carcinoma cell line HepG2. Ascorbic acid and β-carotene were applied to cells as plasma peak concentrations (70 and 8 μM, respectively) and their half concentrations (35 and 4 μM, respectively) for 24 and 48 h. Genotoxic and cytotoxic effects of ascorbic acid and β-carotene were evaluated by alkali single cell gel electrophoresis (SCGE), acridine orange/ethidium bromide staining patterns of cells (apoptosis and necrosis) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Results of the SCGE demonstrated that both ascorbic acid and β-carotene caused DNA damage on HepG2 which were also concordant to increased apoptosis and necrosis of cells. Increased TBARS values also demonstrated increased lipid peroxidation in these cells. Results of the present study demonstrates that when dietary intakes of ascorbic acid and β-carotene and their relevant achievable plasma level concentrations were considered, both ascorbic acid and β-carotene induce genotoxic and cytotoxic damage on HepG2 together with increased oxidative damage in contrast to their protective effect on healthy cells. This may be correlated to oxidative status and balance of ROS in hepatocellular carcinoma cells.

Expression profiling of nuclear receptors in the NCI60 cancer cell panel reveals receptor-drug and receptor-gene interactions

We profiled the expression of the 48 human nuclear receptors (NRs) by quantitative RT-PCR in 51 human cancer cell lines of the NCI60 collection derived from nine different tissues. NR mRNA expression accurately classified melanoma, colon, and renal cancers, whereas lung, breast, prostate, central nervous system, and leukemia cell lines exhibited heterogeneous receptor expression. Importantly, receptor mRNA levels faithfully predicted the growth-inhibitory qualities of receptor ligands in nonendocrine tumors. Correlation analysis using NR expression profiles and drug response information across the cell line panel uncovered a number of new potential receptor-drug interactions, suggesting that in these cases, individual receptor levels may predict response to chemotherapeutic interventions. Similarly, by cross-comparing receptor levels within our expression dataset and relating these profiles to existing microarray gene expression data, we defined interactions among receptors and between receptors and other genes that can now be mechanistically queried. This work supports the strategy of using NR expression profiling to classify various types of cancer, define NR-drug interactions and receptor-gene networks, predict cancer-drug sensitivity, and identify druggable targets that may be pharmacologically manipulated for potential therapeutic intervention.

beta-Carotene and beta-cryptoxanthin but not lutein evoke redox and immune changes in RAW264 murine macrophages

The mechanism of immunological benefits induced by carotenoids has not been fully elucidated. Here, we investigated some of the immunity-related properties of beta-carotene and two other carotenoids, beta-cryptoxanthin, and lutein, on the murine macrophages cell line RAW264. beta-Carotene added to the culture medium accumulated in the cells in a time- and dose-dependent manner. The accumulation was positively correlated with cellular lipid peroxidation, demonstrating the pro-oxidative activity of beta-carotene, and also with the synthesis of glutathione, an intracellular antioxidant. Conversely, accumulation of beta-carotene was negatively correlated with the transcription of immune-active molecules, such as IL-1beta, IL-6, and IL-12 p40, in cells stimulated by LPS and INF-gamma. The transcription of the pro-inflammatory cytokines IL-1beta and IL-6 was more sensitive to the accumulation of beta-carotene than was IL-12 p40. The accumulation of beta-cryptoxanthin in cells resulted in effects similar to those of beta-carotene. However, lutein accumulated minimally and did not significantly affect the cells. These results demonstrate that beta-carotene, and beta-cryptoxanthin as well, can accumulate in RAW264 cells and induce changes in intracellular redox status, which in turn regulate the immune function of macrophages.

Effects of retinoic acid isomers on apoptosis and enzymatic antioxidant system in human breast cancer cells

Retinoic acids (RAs) modulate growth, differentiation, and apoptosis in normal, pre-malignant & malignant cells. In the present study, the effects of RA isomers (all-trans RA, 13-cis RA, and 9-cis RA) on the cell signal transduction of human breast cancer cells have been studied. The relationship between RAs and an enzymatic antioxidant system was also determined. Estrogen-receptor (ER) positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cells were treated with different doses of each RA isomers, all-trans RA, 13-cis RA, or 9-cis RA. Treatment of RA isomers inhibited cell viability and induced apoptosis of MCF-7 cells as a result of increased caspase activity in cytoplasm and cytochrome C released from mitochondria. All-trans RA was the most effective RA isomer in both cell growth inhibition and induction of apoptosis in MCF-7 cells. However, no significant effect of RA isomers was observed on the cell growth or apoptosis in ER-negative MDA-MB-231 cells. In addition, activities of antioxidant enzymes such as catalase and glutathione peroxidase were decreased effectively after treatment of RA in MCF-7 cells, whereas SOD activity was rarely affected. Thus, the present data suggest that all-trans RA is the most potential inducer of apoptosis and modulator of antioxidant enzymes among RA isomers in MCF-7 human breast cancer cells.

Greater vegetable and fruit intake is associated with a lower risk of breast cancer among Chinese women

The effect of vegetable and fruit consumption on breast cancer risk is controversial. We examined the association between vegetable and fruit intake and breast cancer risk in a hospital-based case-control study conducted in Guangdong, China. Four hundred and thirty-eight cases were frequency matched to 438 controls by age (5-year interval) and residence (rural/urban). Dietary intake was assessed by face-to-face interviews using a validated food frequency questionnaire. Multivariate logistic regression was used to estimate the odds ratios (ORs) and 95% confidence interval (CI) after adjusting for various potential confounders. Total vegetable and fruit intake was found to be inversely associated with breast cancer risk. The ORs of the highest quartile relative to the lowest quartile of total vegetable and fruit intake were 0.28 (95% CI 0.18-0.43) and 0.53 (95% CI 0.34-0.82), respectively. Consumption of individual vegetable and fruit groups such as dark green leafy vegetables, cruciferous vegetables, carrots and tomatoes, banana, watermelon/papaya/cantaloupe were all inversely and significantly related with breast cancer risk. An inverse association was also observed for vitamin A, carotene, vitamin C, vitamin E, and fiber intake. These data indicate that greater intake of vegetables and fruits is associated with a decreased risk of breast cancer among Chinese women residing in Guangdong.

The vitamin A family can significantly decrease the expression of ERbeta of ERs positive breast cancer cells in the presence or absence of ER ligands and paclitaxel

Taxanes have high activity against breast cancer cells either as the single agent or in combination with other anticancer compounds. The aim of the study was to determine the effects of vitamin A compounds on the cytotoxic action of paclitaxel and on the expression of ERs in the MCF-7 breast cancer cells. Retinol and beta-carotene, but not retinoids, added to the culture exerted an effect on paclitaxel activity. However, only beta-carotene significantly reduced the percentage of proliferating cells (40.36% +/- 5.64, p < 0.01). We observed that vitamin A and its derivatives combined with paclitaxel and estradiol decreased the percentage of proliferating cells, but only in comparison to estradiol group, whereas retinol and lycopene administered together with paclitaxel and tamoxifen decrease significantly the percentage of proliferatin cells (36.85% +/- 4.71, p < 0.0001 and 37.22% +/- 1.59, p < 0.0001 respectively, compared with paclitaxel group). We have shown that paclitaxel increases the expression of ERalpha and ERbeta mRNA in MCF-7 line. The strongest effect of transcription inhibition ERalpha (2.5 times) and especially ERbeta (10 times) was observed after addition of 9-cis retinoic acid and paclitaxel. This data suggests a synergistic effect of the compounds on ERbeta down-regulation. Our results support the use of retinoid is treatment of ER positive breast cancer patients.