Alcohol intake and late-stage promotion of breast cancer

Reduced S-nitrosylation of TGFβ1 elevates its binding affinity toward the receptor and promotes fibrogenic signaling in the breast

Transforming Growth Factor β (TGFβ) is a pleiotropic cytokine closely linked to tumors. Previously, we pharmacologically inhibited basal nitric oxide (NO) production in healthy mammary glands and found that this induced precancerous progression accompanied by upregulation of TGFβ and desmoplasia. In the present study, we tested whether NO directly S-nitrosylates (forms an NO-adduct at a cysteine residue) TGFβ for inhibition, whereas reduction of NO denitrosylates TGFβ for de-repression. We introduced mutations to 3 C-terminal cysteines of TGFβ1 which were predicted to be S-nitrosylated. We found that these mutations indeed impaired S-nitrosylation of TGFβ1 and shifted the binding affinity towards the receptor from the latent complex. Furthermore, in silico structural analyses predicted that these S-nitrosylation-defective mutations strengthen the dimerization of mature protein, whereas S-nitrosylation-mimetic mutations weaken the dimerization. Such differences in dimerization dynamics of TGFβ1 by denitrosylation/S-nitrosylation likely account for the shift of the binding affinities toward the receptor versus latent complex. Our findings, for the first time, unravel a novel mode of TGFβ regulation based on S-nitrosylation or denitrosylation of the protein.

Reduced S-nitrosylation of TGFβ1 elevates its binding affinity towards the receptor and promotes fibrogenic signaling in the breast

Transforming Growth Factor β (TGFβ) is a pleiotropic cytokine closely linked to tumors. TGFβ is often elevated in precancerous breast lesions in association with epithelial-to-mesenchymal transition (EMT), indicating its contribution to precancerous progression. We previously reported that basal nitric oxide (NO) levels declined along with breast cancer progression. We then pharmacologically inhibited NO production in healthy mammary glands of wild-type mice and found that this induced precancerous progression accompanied by desmoplasia and upregulation of TGFβ activity. In the present study, we tested our hypothesis that NO directly S-nitrosylates (forms an NO-adduct at a cysteine residue) TGFβ to inhibit the activity, whereas the reduction of NO denitrosylates TGFβ and de-represses the activity. We introduced mutations to three C-terminal cysteines of TGFβ1 which were predicted to be S-nitrosylated. We found that these mutations indeed impaired S-nitrosylation of TGFβ1 and shifted the binding affinity towards the receptor from the latent complex. Furthermore, in silico structural analyses predicted that these S-nitrosylation-defective mutations strengthen the dimerization of mature protein, whereas S-nitrosylation-mimetic mutations weaken the dimerization. Such differences in dimerization dynamics of TGFβ1 by denitrosylation/S-nitrosylation likely account for the shift of the binding affinities towards the receptor vs. latent complex. Our findings, for the first time, unravel a novel mode of TGFβ regulation based on S-nitrosylation or denitrosylation of the protein.

Reduced Basal Nitric Oxide Production Induces Precancerous Mammary Lesions via ERBB2 and TGFβ

One third of newly diagnosed breast cancers in the US are early-stage lesions. The etiological understanding and treatment of these lesions have become major clinical challenges. Because breast cancer risk factors are often linked to aberrant nitric oxide (NO) production, we hypothesized that abnormal NO levels might contribute to the formation of early-stage breast lesions. We recently reported that the basal level of NO in the normal breast epithelia plays crucial roles in tissue homeostasis, whereas its reduction contributes to the malignant phenotype of cancer cells. Here, we show that the basal level of NO in breast cells plummets during cancer progression due to reduction of the NO synthase cofactor, BH₄, under oxidative stress. Importantly, pharmacological deprivation of NO in prepubertal to pubertal animals stiffens the extracellular matrix and induces precancerous lesions in the mammary tissues. These lesions overexpress a fibrogenic cytokine, TGFβ, and an oncogene, ERBB2, accompanied by the occurrence of senescence and stem cell-like phenotype. Consistently, normalization of NO levels in precancerous and cancerous breast cells downmodulates TGFβ and ERBB2 and ameliorates their proliferative phenotype. This study sheds new light on the etiological basis of precancerous breast lesions and their potential prevention by manipulating the basal NO level.

Chronic ethanol exposure enhances the aggressiveness of breast cancer: the role of p38γ

Both epidemiological and experimental studies suggest that ethanol may enhance aggressiveness of breast cancer. We have previously demonstrated that short term exposure to ethanol (12–48 hours) increased migration/invasion in breast cancer cells overexpressing ErbB2, but not in breast cancer cells with low expression of ErbB2, such as MCF7, BT20 and T47D breast cancer cells. In this study, we showed that chronic ethanol exposure transformed breast cancer cells that were not responsive to short term ethanol treatment to a more aggressive phenotype. Chronic ethanol exposure (10 days - 2 months) at 100 (22 mM) or 200 mg/dl (44 mM) caused the scattering of MCF7, BT20 and T47D cell colonies in a 3-dimension culture system. Chronic ethanol exposure also increased colony formation in an anchorage-independent condition and stimulated cell invasion/migration. Chronic ethanol exposure increased cancer stem-like cell (CSC) population by more than 20 folds. Breast cancer cells exposed to ethanol in vitro displayed a much higher growth rate and metastasis in mice. Ethanol selectively activated p38γ MAPK and RhoC but not p38α/β in a concentration-dependent manner. SP-MCF7 cells, a derivative of MCF7 cells which compose mainly CSC expressed high levels of phosphorylated p38γ MAPK. Knocking-down p38γ MAPK blocked ethanol-induced RhoC activation, cell scattering, invasion/migration and ethanol-increased CSC population. Furthermore, knocking-down p38γ MAPK mitigated ethanol-induced tumor growth and metastasis in mice. These results suggest that chronic ethanol exposure can enhance the aggressiveness of breast cancer by activating p38γ MAPK/RhoC pathway.

ErbB2 and p38γ MAPK mediate alcohol-induced increase in breast cancer stem cells and metastasis

Background

Both epidemiological and experimental studies suggest that excessive alcohol exposure increases the risk for breast cancer and enhances metastasis/recurrence. We have previously demonstrated that alcohol enhanced the migration/invasion of breast cancer cells and cancer cells overexpressing ErbB2/HER2 were more sensitive to alcohol exposure. However, the underlying mechanisms remain unclear. This study was designed to investigate the mechanisms underlying alcohol-enhanced aggressiveness of breast cancer. Cancer stem cells (CSCs) play a critical role in cancer metastasis and recurrence.

Methods

We evaluated the effect of chronic alcohol exposure on mammary tumor development/metastasis in MMTV-neu transgenic mice and investigated the cell signaling in response to alcohol exposure in breast cancer cells overexpressing ErbB2/HER2.

Results and discussion

Chronic alcohol exposure increased breast cancer stem cell-like CSC population and enhanced the lung and colon metastasis in MMTV-neu transgenic mice. Alcohol exposure caused a drastic increase in CSC population and mammosphere formation in breast cancer cells overexpressing ErbB2/HER2. Alcohol exposure stimulated the phosphorylation of p38γ MAPK (p-p38γ) which was co-localized with phosphorylated ErbB2 and CSCs in the mammary tumor tissues. In vitro results confirmed that alcohol activated ErbB2/HER2 and selectively increased p-p38γ MAPK as well as the interaction between p38γ MAPK and its substrate, SAP97. However, alcohol did not affect the expression/phosphorylation of p38α/β MAPKs. In breast cancer cell lines, high expression of ErbB2 and p-p38γ MAPK was generally correlated with more CSC population. Blocking ErbB2 signaling abolished heregulin β1- and alcohol-stimulated p-p38γ MAPK and its association with SAP97. More importantly, p38γ MAPK siRNA significantly inhibited an alcohol-induced increase in CSC population, mammosphere formation and migration/invasion of breast cancer cells overexpressing ErbB2.

Conclusions

p38γ MAPK is downstream of ErbB2 and plays an important role in alcohol-enhanced aggressiveness of breast cancer. Therefore, in addition to ErbB2/HER2, p38γ MAPK may be a potential target for the treatment of alcohol-enhanced cancer aggressiveness.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0532-4) contains supplementary material, which is available to authorized users.

Influence of metabolic indicators, smoking, alcohol and socioeconomic position on mortality after breast cancer

BACKGROUND

Factors differently distributed among social groups like obesity, metabolic syndrome, diabetes, smoking, and alcohol intake predict survival after breast cancer diagnosis and therefore might mediate part of the observed social inequality in survival.

MATERIAL AND METHODS

We conducted a cohort study among 1250 postmenopausal breast cancer patients identified among 29 875 women in the Danish Diet, Cancer and Health Study. Participants completed questionnaires and anthropometric measurements were made at enrollment. Information on survival, socioeconomic position, and comorbidity was obtained by linkage to national Danish registries. Clinical information was obtained from the nationwide Danish Breast Cancer Database. Selected information was obtained from hospital records at time of diagnosis. All analyses were based on Cox proportional hazard models, using death from all causes as outcome.

RESULTS

Median follow-up was 9.6 years [interquartile range (IQR), 2.2-17.0 years]. The hazard ratio (HR) for death from all causes increased with lower education (p for trend, 0.01). Adjustment for disease-related prognostic factors, comorbidity and metabolic indicators measured as BMI, waist circumference and diabetes, and smoking and alcohol affected but did not explain the social gradient.

CONCLUSION

The findings indicate that these factors explain some but not all the social inequality in survival after breast cancer and that improvement of lifestyle to some extent would improve survival among women with low socioeconomic position.

Alcohol promotes mammary tumor growth through activation of VEGF-dependent tumor angiogenesis

Alcohol consumption has been recognized as a risk factor for breast cancer. Experimental studies demonstrate that alcohol exposure promotes the progression of existing mammary tumors. However, the mechanisms underlying this effect remain unclear. In the present study, the role of vascular endothelial growth factor (VEGF) in alcohol promotion of breast cancer development was investigated using a mouse xenograft model of mammary tumors and a three-dimensional (3D) tumor/endothelial cell co-culture system. For the mouse xenograft model, mouse E0771 breast cancer cells were implanted into the mammary fat pad of C57BL6 mice. These mice were exposed to alcohol in their drinking water. For the 3D co-culture system, E0771 cells and MDA-MB231 breast cancer cells were co-cultured with SVEC4-10EE2 and human umbilical vein endothelial cells, respectively. The results demonstrated that alcohol increased tumor angiogenesis and accelerated tumor growth. Furthermore, it appeared that alcohol induced VEGF expression in breast cancer cells in vitro and in vivo. Blocking VEGF signaling by SU5416 inhibited tumor angiogenesis in the 3D tumor/endothelial cell co-culture system. Furthermore, injection of SU5416 into mice inhibited alcohol-promoted mammary tumor growth in vivo. These results indicate that alcohol may promote mammary tumor growth by stimulating VEGF-dependent angiogenesis.

Ethanol promotes mammary tumor growth and angiogenesis: the involvement of chemoattractant factor MCP-1

Alcohol consumption is a risk factor for breast cancer in humans. Experimental studies indicate that alcohol exposure promotes malignant progression of mammary tumors. However, the underlying cellular and molecular mechanisms remain unclear. Alcohol induces a pro-inflammatory response by modulating the expression of cytokines and chemokines. Monocyte chemoattractant protein-1 (MCP-1), also known as chemokine (C-C motif) ligand 2, is a pro-inflammatory chemokine implicated in breast cancer development/malignancy. We investigated the role of MCP-1 in alcohol-promoted mammary tumor progression. Using a xenograft model, we demonstrated that alcohol increased tumor angiogenesis and promoted growth/metastasis of breast cancer cells in C57BL/6 mice. Alcohol up-regulated the expression of MCP-1 and its receptor CCR2 in breast cancer cells in vitro and in vivo. Using a three-dimensional tumor/endothelial cell co-culture system, we demonstrated MCP-1 regulated tumor/endothelial cell interaction and promoted tumor angiogenesis. More importantly, MCP-1 mediated alcohol-promoted angiogenesis; an antagonist of the MCP-1 receptor CCR2 significantly inhibited alcohol-stimulated tumor angiogenesis. The CCR2 antagonist abolished ethanol-stimulated growth of mammary tumors in mice. We further demonstrated that MCP-1 enhanced the migration, but not the proliferation of endothelial cells as well as breast cancer cells. These results suggest that MCP-1 plays an important role in ethanol-stimulated tumor angiogenesis and tumor progression.

Alcohol consumption promotes mammary tumor growth and insulin sensitivity

Epidemiological data show that in women, alcohol has a beneficial effect by increasing insulin sensitivity but also a deleterious effect by increasing breast cancer risk. These effects have not been shown concurrently in an animal model of breast cancer. Our objective is to identify a mouse model of breast cancer whereby alcohol increases insulin sensitivity and promotes mammary tumorigenesis. Our results from the glucose tolerance test and the homeostasis model assessment show that alcohol consumption improved insulin sensitivity. However, alcohol-consuming mice developed larger mammary tumors and developed them earlier than water-consuming mice. In vitro results showed that alcohol exposure increased the invasiveness of breast cancer cells in a dose-dependent manner. Thus, this animal model, an in vitro model of breast cancer, may be used to elucidate the mechanism(s) by which alcohol affects breast cancer.

Alcohol and breast cancer: the mechanisms explained

Breast cancer is a leading cause of death amongst women, several studies have shown significant association between alcohol consumption and breast cancer. The aim of this overview is to highlight some of the mechanisms by which alcohol consumption could increase the risk of developing breast cancer. Using online Medline search engine, article containing details about mechanisms which explain the link between alcohol and breast cancer were examined. A number of mechanisms were found by which alcohol could increase the risk of breast cancer, alcohol's interaction and effect on oestrogen secretion; number of oestrogen receptors; the generation of acetaldehyde and hydroxyl free radicals; cells migration and metastasis; secretion of IGF1 and interaction with HRT and folate metabolism. In conclusion, it is essential for clinicians to understand these mechanisms and inform patients of the link between alcohol and breast cancer.

Alcohol intake and breast cancer risk among young women

INTRODUCTION

Alcohol intake has been consistently associated with breast cancer risk, but the importance of timing of intake and the impact of beverage type are unclear.

METHODS

We evaluated whether early, lifetime or recent alcohol intake was associated with breast cancer risk, and whether risk varied by type of alcoholic drinks in 1,728 newly diagnosed population-based breast cancer patients and 435 control subjects aged 20-49 years. We used multivariable logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) as measures of the relative risk of breast cancer associated with intake of alcoholic drinks.

RESULTS

Intake of alcoholic drinks during the recent five year period before the breast cancer diagnosis was associated with increased breast cancer risk (P (trend) = 0.04). Intake of two or more alcoholic drinks per day during this five year period was associated with an 82% increase in breast cancer risk relative to never drinkers (OR = 1.82, 95% CI = 1.01-3.28). No risk increase was observed for alcohol intake at ages 15-20 years or for lifetime alcohol intake. Risk did not vary by type of alcohol consumed.

CONCLUSIONS

Our results suggest that recent alcohol consumption may be associated with increased breast cancer risk in young women.

Modifiable Risk Factors for Breast Cancer Recurrence: What Can We Tell Survivors?

The potential for recurrence causes considerable distress for breast cancer survivors. Major information sources for survivors and providers offer few clear recommendations for postdiagnosis lifestyle change related to recurrence. To design interventions to improve long-term survivors' care and quality of life, we must know what survivors are doing to prevent recurrence in the absence of solid evidence, whether survivors' perceptions and behaviors correspond to hypothesized modifiable risk factors for recurrence, and whether survivors are adopting behaviors that could otherwise be harmful to their health. Our review first addresses the general lack of consensus on the impact of specific lifestyle factors on breast cancer recurrence and the resulting equivocal lifestyle recommendations for survivors. Second, we describe inadequacies of the studies of survivors' lifestyle changes related to recurrence. Because much of the existing knowledge about modifiable risk factors for recurrence comes from studies of survivors whose participation and behavior change were potentially influenced by their concern about recurrence, we need large, population-based observational studies of randomly selected breast cancer survivors, adequately representing the target population. Critical are data on lifestyle change from prediagnosis to postdiagnosis and changes over time after diagnosis, extensive data on conventional and nonconventional treatments, and the temporal relationship between behaviors and treatments, and inclusion of the full complement of potential lifestyle risk factors for recurrence. Understanding in detail the current status of survivors' perceptions and behaviors related to modifiable risk factors for recurrence can provide considerable practical information to inform future interventions and communication strategies for breast cancer survivors.

College students' knowledge of risk and screening recommendations for breast, cervical, and testicular cancers

BACKGROUND

There is a gap in the literature regarding the knowledge of college students about breast, cervical, and testicular cancers.

METHODS

I surveyed 3362 college students were surveyed about their knowledge of risk factors and screening recommendations for these 3 cancers during the 2002-2003 school year at a large public university in the Northeast.

RESULTS

Students knew approximately 50% of the information about risk factors and screening recommendations for these 3 cancers. CONCLUSIONS. Based on these results, college students appear to have limited knowledge about breast, cervical, and testicular cancers and need education about them.

Role of matrix metalloproteinase-2 in ethanol-induced invasion by breast cancer cells

Ethanol is a tumor promoter and may enhance the metastasis of breast cancer. However, the underlying cellular/molecular mechanisms remain unknown. Amplification of ErbB2, a receptor tyrosine kinase, is found in 20-30% of breast cancer patients. Ethanol preferably stimulates invasion by breast cancer cells over-expressing ErbB2 in vitro. Over-expression of ErbB2 is positively associated with elevated levels of matrix metalloproteinase-2 (MMP-2) and MMP-9. Ethanol at physiologically relevant concentrations activates MMP-2 without altering its expression level in mammary epithelial cells over-expressing ErbB2, but not in cells expressing low levels of ErbB2. The activation is dependent on c-jun N-terminal kinases (JNK) and reactive oxygen species. Selective inhibitors of MMP-2 and anti-oxidants significantly inhibit ethanol-stimulated cell invasion. Similarly, knocking down MMP-2 by small interference RNA induces a partial blockage on ethanol-promoted cell invasion. Matrix metalloproteinase-2 is predominantly expressed in stromal fibroblasts; ethanol also activates fibroblastic MMP-2. The conditioned medium collected from ethanol-exposed fibroblasts dramatically stimulates the invasion of breast cancer cells. The role of MMP-2 in ethanol-induced tumor promotion is discussed.

MMP-2 mediates ethanol-induced invasion of mammary epithelial cells over-expressing ErbB2

Ethanol is a tumor promoter and may enhance the metastasis of breast cancer. We have previously demonstrated that over-expression of ErbB2 promoted ethanol-mediated invasion of mammary epithelial cells and breast cancer cells. However, the underlying cellular/molecular mechanisms remain unknown. By gelatin zymography, we showed that over-expression of ErbB2 increased the production of matrix metalloproteinase-2 (MMP-2) and MMP-9 in human mammary epithelial cells (HB2). Transient or stable transfection of ErbB2 cDNA to HB2 cells upregulated the transcripts and the activity of the MMP-2/-9 gene promoter; the upregulation of MMP-2/-9 expression was mediated by p38 mitogen-activated protein kinase (p38 MAPK) and phosphatidylinositol 3-kinase (PI3K). Although ethanol, at physiologically relevant concentrations (100-400 mg/dl), did not affect the production of MMP-2/-9, it activated MMP-2 in HB2 cells over-expressing ErbB2 (HB2(ErbB2)), but not HB2 cells; it enhanced the cleavage of proform MMP-2 (72 kDa) to an active form (62 kDa). The activation was dependent on c-jun N-terminal kinases (JNKs) and reactive oxygen species (ROS). On the other hand, ethanol affected neither the expression nor the activation of MMP-9. Selective inhibitors of MMP-2 (SB-3CT and OA-Hy) and antioxidants significantly inhibited ethanol-stimulated invasion of HB2(ErbB2) cells. Furthermore, knocking down MMP-2 by small interference RNA also induced a partial blockage on ethanol-promoted invasion of HB2(ErbB2) cells. Thus, ethanol-stimulated invasion of cells over-expressing ErbB2 was mediated, at least partially, by MMP-2 activation.

National Institute on Alcohol Abuse and Alcoholism Report on Moderate Drinking

In support of the 2005 update of the U.S. Department of Agriculture/U.S. Department of Health and Human Services Dietary Guidelines, the National Institute on Alcohol Abuse and Alcoholism was asked to assess the strength of the evidence related to health risks and potential benefits of moderate alcohol consumption, with particular focus on the areas of cardiovascular disease, breast cancer, obesity, birth defects, breastfeeding, and aging. The findings were reviewed by external researchers with extensive research backgrounds on the consequences and benefits of alcohol consumption. This report now serves as the National Institutes of Health's formal position paper on the health risks and potential benefits of moderate alcohol use.

Investigation of systemic folate status, impact of alcohol intake and levels of DNA damage in mononuclear cells of breast cancer patients

Folate is required for DNA synthesis, repair and methylation. Low folate status has been implicated in carcinogenesis, possibly as a result of higher rate of genetic damage. The aim of this study is to compare folate status and levels of DNA damage between breast cancer and benign breast disease control patients. Fasting blood samples from 64 histologically confirmed untreated breast cancer patients (mean age 57 years) and 30 benign breast disease control patients (mean age 51 years) were obtained. Red cell folate (RCF) and plasma homocysteine were measured. Mononuclear cells (MNC) were isolated for genetic damage analysis using the basic alkaline comet assay. Results are expressed as tail moment. Data were log transformed as appropriate before analysis for normalisation purposes. The geometric mean (95% confidence interval) of RCF (ng ml⁻¹) in breast cancer patients was 339.07 (333.3–404.6) vs 379.5 (335.8–505.2) in control patients (P=0.24). Corresponding plasma homocysteine concentrations (μmol l⁻¹) were 11.9 (10.6–16.4) vs 10.1 (9.3–11.9) (P=0.073), respectively. The mean tail moment (s.d.) of DNA damage in MNC of breast cancer patients detected by the basic comet assay was 1.4 (0.66) vs –0.17 (0.79) in controls (P<0.0001, t-test), the modified comet assay ‘endonuclease III (Endo III)’ was 1.7 (0.70) vs 0.86 (0.81) (P<0.0001, t-test), and the modified comet assay ‘formamidopyrimidine glycosylase (FPG)’ was 1.6 (0.62) vs 0.99 (0.94) (P<0.0001, t-test). There was a significant negative correlation between RCF levels and DNA damage detected by modified comet assay ‘FPG’ (Pearson Correlation Coefficient r²=−0.26, P=0.02) and DNA damage was found to be significantly higher in MNC of breast cancer patients compared to benign breast disease control patients. Breast cancer patients tended to have lower RCF levels and higher levels of plasma homocysteine, but these differences were not significant. The study provides preliminary evidence that reduced folate status may be implicated in the aetiology of breast cancer perhaps by increasing the in vivo level of genetic instability.

Ethanol-induced in vitro invasion of breast cancer cells: the contribution of MMP-2 by fibroblasts

Ethanol is a tumor promoter and may promote metastasis of breast cancer. However, the underlying cellular/molecular mechanisms remain unknown. Overexpression and high activity of matrix metalloproteinase-2 (MMP-2) are frequently associated with metastatic breast cancers and serve as a prognostic indicator of clinical outcome. MMP-2 is predominantly expressed in stromal fibroblasts and plays a pivotal role in regulating the invasive behavior of breast tumor cells. We hypothesized that ethanol may enhance the invasion of breast tumor cells by modulating the activity of fibroblastic MMP-2. With in vitro models (HS68 and CCD1056SK human fibroblasts), we showed that ethanol at physiologically relevant concentrations (50-200 mg/dl) activated MMP-2; conversely, at a higher concentration (400 mg/dl), it inhibited the MMP-2 activity. Consistently, conditioned medium collected from ethanol (50-200 mg/dl)-exposed fibroblasts markedly enhanced the invasive potential of breast cancer cells and mammary epithelial cells overexpressing ErbB2/HER2 (BT474, SKBR-3 and HB2(ErbB2) cells) but had little effect on cells with low ErbB2 levels (BT20 and HB2 cells). In contrast, conditioned medium obtained from ethanol (400 mg/dl)-treated fibroblasts inhibited cell invasion. Selective inhibitors of MMP-2 (SB-3CT and OA-Hy) eliminated ethanol-stimulated invasion, indicating that the effect of ethanol was mediated by MMP-2. Ethanol activated conventional PKCs and JNKs in fibroblasts; inhibitors of PKC (Go6850 and Go6976) and JNKs (SP600125) significantly inhibited ethanol-mediated MMP-2 activation as well as cell invasion, indicating that PKCs and JNKs play a role in ethanol-induced MMP-2 activation and cell invasion in vitro. Thus, ethanol-promoted breast cancer cell invasion may be mediated by the modulation of fibroblastic MMP-2.

Use of Oral Contraceptives, Alcohol, and Risk for Invasive Breast Cancer

The aim of our study was to examine how the use of oral contraceptives (OCs) interact with alcohol on breast cancer risk within the large prospective follow-up study, Norwegian Women and Cancer Study. Between 1991 and 1997, women aged 30 to 70 years were drawn at random from the central person register and mailed an invitation. Follow-up information was collected throughout 2001 by linkage to national registries. Only women (n = 86,948) with complete information on alcohol consumption and duration of OC use were included in the present analysis. A total of 1,130 invasive breast cancers were diagnosed during 618,638 person-years of follow-up. Consumption of ≥10.0 g/d alcohol was associated with a breast cancer relative risk (95% confidence interval) of 1.69 (1.32-2.15), consistent with a linear relationship (P for trend &lt; 0.0001). Among alcohol consumers, an excess risk of breast cancer was observed for total duration of OC use only among women who consumed &lt;5 g/d alcohol (P for trend = 0.0009). We observed a negative interaction between duration of OC use and alcohol consumption effects (P for interaction = 0.01). After stratification on menopausal status, the association between high alcohol intake and breast cancer was more prominent among postmenopausal women than among premenopausal women (P for heterogeneity = 0.01). No interaction between alcohol and duration of OC use were significant after stratification on menopausal status. Our findings in conjunction with biological data imply that alcohol and OCs have antagonistic effects on breast cancer risk through a common pathway. Whether the interactive effect differs according to menopausal status remains unclear and needs further investigations.

Increased fruit, vegetable and fiber intake and lower fat intake reported among women previously treated for invasive breast cancer

OBJECTIVE

To describe the dietary intake patterns of women before and after breast cancer diagnosis.

SUBJECTS AND SETTING

3,084 women (age range 27 to 70 years) who had been treated for early-stage breast cancer, who were free of recurrent disease, and who were willing to complete study questionnaires.

DESIGN

A descriptive analysis of baseline demographic and lifestyle questionnaire data, including reported dietary intake data from women who have had breast cancer participating in a randomized, controlled dietary intervention trial. Outcomes include dietary intakes of high- and low-fat foods, fruits and vegetables, and whole grains.

STATISTICAL ANALYSIS PERFORMED

Analyses included frequency of intake of selected food items, chi2 analysis to determine associations between reported intakes and demographic and personal characteristics, and logistic regression to assess odds of making more healthful changes.

RESULTS

Women who have had breast cancer reported higher fruit, vegetable, and fiber-rich food intakes (58%, 60%, 38% more, respectively) and lower intakes of high-fat foods, including fast foods, after diagnosis. Those older than age 60 years were more likely to report no change in intake, including red meat (41%), vegetables (51%), and whole grains (62%). Odds ratios (OR) for more healthful diet choices varied by age and time since diagnosis. The longer the time since diagnosis the more likely women selected low-fat (vs high-fat) foods (OR 1.56, 95% confidence interval [CI] 1.16-2.09 for 3 to 4 years vs <1 year after diagnosis) and reduced added fats (OR 1.47, 95% CI 1.17-1.84 for 3 to 4 years vs <1 year after diagnosis).

APPLICATIONS

Women who have had breast cancer report more healthful diet habits after diagnosis. Through nutrition education and counseling, dietetics professionals may be able to promote healthful and evidence-based eating habits among women previously treated for breast cancer.

Diet and cancer prevention

Research from several sources provides strong evidence that vegetables, fruits, and whole grains, dietary fibre, certain micronutrients, some fatty acids and physical activity protect against some cancers. In contrast, other factors, such as obesity, alcohol, some fatty acids and food preparation methods may increase risks. Unravelling the multitude of plausible mechanisms for the effects of dietary factors on cancer risk will likely necessitate that nutrition research moves beyond traditional epidemiological and metabolic studies. Nutritional sciences must build on recent advances in molecular biology and genetics to move the discipline from being largely 'observational' to focusing on 'cause and effect'. Such basic research is fundamental to cancer prevention strategies that incorporate effective dietary interventions for target populations.

Stimulation of cell invasion and migration by alcohol in breast cancer cells

Increasing epidemiological studies suggest that alcohol consumption confers a high risk for development of breast cancer. In this study, we found that biologically relevant concentrations of alcohol elicited a significant stimulation of cell adhesion, migration, and invasion in MCF-7 human breast cancer cells. Moreover, the promotion of invasion and migration potential by alcohol was associated with the significant decrease of E-cadherin, alpha, beta, and gamma three major catenin, and BRCA1 expression. In addition, an enhanced expression of BRCA1 significantly blocked alcohol-stimulated cell invasion. Thus, our present study suggests that alcohol as a breast cancer risk factor plays an important role not only in carcinogenesis, but also in promotion of cell invasion and migration.