Na+,HCO3- cotransporter NBCn1 accelerates breast carcinogenesis.

Cell metabolism increases during carcinogenesis. Yet, intracellular pH in solid cancer tissue is typically maintained equal to or above that of normal tissue. This is achieved through accelerated cellular acid extrusion that compensates for the enhanced metabolic acid production. Upregulated Na+,HCO3- cotransport is the predominant mechanism of net acid extrusion in human and murine breast cancer tissue, and in congruence, the protein expression of the electroneutral Na+,HCO3- cotransporter NBCn1 is increased in primary breast carcinomas and lymph node metastases compared to matched normal breast tissue. The capacity for net acid extrusion and level of steady-state intracellular pH are lower in carcinogen- and ErbB2-induced breast cancer tissue from NBCn1 knockout mice compared to wild-type mice. Consistent with importance of intracellular pH control for breast cancer development, tumor-free survival is prolonged and tumor growth rate decelerated in NBCn1 knockout mice compared to wild-type mice. Glycolytic activity increases as function of tumor size and in areas of poor oxygenation. Because cell proliferation in NBCn1 knockout mice is particularly reduced in larger-sized breast carcinomas and central tumor regions with expected hypoxia, current evidence supports that NBCn1 facilitates cancer progression by eliminating intracellular acidic waste products derived from cancer cell metabolism. The present review explores the mechanisms and consequences of acid-base regulation in breast cancer tissue. Emphasis is on the Na+,HCO3- cotransporter NBCn1 that accelerates net acid extrusion from breast cancer tissue and thereby maintains intracellular pH in a range permissive for cell proliferation and development of breast cancer.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast.

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.

Delphinidin suppresses breast carcinogenesis through the HOTAIR/microRNA-34a axis.

Delphinidin, one of the main anthocyanidins, has potent anti-cancer properties. In this study, we investigated the effect of delphinidin on 1-methyl-1-nitrosourea (MNU)-induced breast carcinogenesis on rats and the mechanism of delphinidin via negative regulation of the HOTAIR/microRNA-34a axis. We found administration of delphinidin could effectively suppress MNU-induced mammal breast carcinogenesis. Delphinidin downregulated the level of HOTAIR and upregulated miR-34a in breast carcinogenesis. Western blot analysis confirmed that delphinidin treatment can significantly decrease the expression of ß-catenin, glycogen synthase kinase-3ß (Gsk3ß), c-Myc, cyclin-D1, and matrix metalloproteinase-7(MMP-7) expression in breast cancer cells, and inhibition of miR-34a significantly reduced the effect of delphinidin on c-Myc, cyclin-D1, and MMP-7. HOTAIR overexpression also blocked the effect of delphinidin on miR-34a and the Wnt/ß-catenin signaling pathway in MDA-MB-231 cells. RNA immunoprecipitation (RIP) assay and chromatin immunoprecipitation (ChIP) assay results showed that delphinidin upregulated miR-34a by inhibiting HOTAIR, coupled with enhancement of the zeste homolog 2 (EZH2) and histone H3 Lys27 trimethylation (H3K27me3). This study indicated that delphinidin may potentially suppress breast carcinogenesis and exert its anti-cancer effect through the HOTAIR/miR-34a axis. These findings provided new evidence for the use of delphinidin in preventing breast carcinogenesis.

Molecular profile of atypical hyperplasia of the breast.

PURPOSE: Atypical ductal and atypical lobular hyperplasia (AH) of the breast are important proliferative lesions which are associated with a significantly increased risk for breast cancer. The breast cancer which develops in association with AH may occur synchronously, representing local progression, or metachronously at a later date in either the ipsilateral or contralateral breast. These high-risk characteristics of AH suggest they contain significant genomic changes. METHODS: To define the genomic changes in AH, a comprehensive review of the literature was conducted to identify the numerical chromosomal and structural chromosomal changes, DNA methylation, and gene expression abnormalities in atypical ductal and atypical lobular hyperplasia. RESULTS: AHs are characterized by advanced genomic changes including aneuploidy, loss of heterozygosity, gross chromosomal rearrangements such as amplifications and large-scale deletions, DNA methylation of tumor suppressor and other genes, and gene expression differences between AH and surrounding normal breast tissue including significant estrogen receptor expression. Many of these changes are shared by an associated synchronous breast cancer, consistent with an important precursor role for AH. At the same time, many of the genomic changes of AHs are also shared by common sporadic breast cancer, consistent with a high risk for future development of metachronous breast cancer. CONCLUSIONS: This molecular profile should help clarify the genomic characteristics and malignant predisposition of AH, and aid in the identification of new targets for the prevention of breast cancer.

Activation of antioxidant defences of human mammary epithelial cells under leptin depend on neoplastic state.

BACKGROUND: Obesity is associated with oxidative stress, a major factor in carcinogenesis, and with high leptin concentration. The aim of this study was to determine the effects of leptin on the antioxidant response in three human mammary epithelial cells each presenting a different neoplastic status: healthy human mammary epithelial cells (HMEC), oestrogen-receptor positive MCF-7 cells and triple-negative MDA-MB-231 cells. METHODS: This in vitro kinetic study characterized the cell antioxidant response after 1, 6 and 24 h in the presence of leptin (10 or 100 ng/ml).The antioxidant response was defined in terms of cell glutathione content, gene expression and catalytic activity of antioxidant enzymes (i.e. glutathione peroxidase 1 (Gpx1), glutathione reductase (GR), glutathione S transferase (GST), heme-oxygenase 1 (HO-1) and cyclooxygenase-2 (COX-2)). Oxidative stress occurrence was assessed by lipid hydro peroxide (HPLIP) and isoprostane concentrations in culture media at 24 h. RESULTS: At both concentrations used, leptin induced ROS production in all cell models, contributing to various antioxidant responses linked to neoplastic cell status. HMEC developed a highly inducible antioxidant response based on antioxidant enzyme activation and an increase in cell GSH content at 10 ng/ml of leptin. However, at 100 ng/ml of leptin, activation of antioxidant response was lower. Conversely, in tumour cells, MCF-7 and MDA-MB-231, leptin did not induce an efficient antioxidant response, at either concentration, resulting in an increase of lipid peroxidation products. CONCLUSIONS: Leptin can modulate the oxidative status of mammary epithelial cells differently according to their neoplastic state. These novel results shed light on oxidative status changes in mammary cells in the presence of leptin.

Somatic loss of estrogen receptor beta and p53 synergize to induce breast tumorigenesis.

BACKGROUND: Upregulation of estrogen receptor beta (ERß) in breast cancer cells is associated with epithelial maintenance, decreased proliferation and invasion, and a reduction in the expression of the receptor has been observed in invasive breast tumors. However, proof of an association between loss of ERß and breast carcinogenesis is still missing. METHODS: To study the role of ERß in breast oncogenesis, we generated mouse conditional mutants with specific inactivation of ERß and p53 in the mammary gland epithelium. For epithelium-specific knockout of ERß and p53, ERß F/F and p53 F/F mice were crossed to transgenic mice that express the Cre recombinase under the control of the human keratin 14 promoter. RESULTS: Somatic loss of ERß significantly accelerated formation of p53-deficient mammary tumors. Loss of the receptor also resulted in the development of less differentiated carcinomas with stronger spindle cell morphology and decreased expression of luminal epithelial markers. CONCLUSIONS: Our results show that synergism between ERß and p53 inactivation functions to determine important aspects of breast oncogenesis and cancer progression.

Docosahexaenoic acid attenuates breast cancer cell metabolism and the Warburg phenotype by targeting bioenergetic function.

Docosahexaenoic acid (DHA; C22:6n-3) depresses mammary carcinoma proliferation and growth in cell culture and in animal models. The current study explored the role of interrupting bioenergetic pathways in BT-474 and MDA-MB-231 breast cancer cell lines representing respiratory and glycolytic phenotypes, respectively and comparing the impacts of DHA with a non-transformed cell line, MCF-10A. Metabolic investigation revealed that DHA supplementation significantly diminished the bioenergetic profile of the malignant cell lines in a dose-dependent manner. DHA enrichment also resulted in decreases in hypoxia-inducible factor (HIF-1α) total protein level and transcriptional activity in the malignant cell lines but not in the non-transformed cell line. Downstream targets of HIF-1α, including glucose transporter 1 (GLUT 1) and lactate dehydrogenase (LDH), were decreased by DHA treatment in the BT-474 cell line, as well as decreases in LDH protein level in the MDA-MB-231 cell line. Glucose uptake, total glucose oxidation, glycolytic metabolism, and lactate production were significantly decreased in response to DHA supplementation; thereby enhancing metabolic injury and decreasing oxidative metabolism. The DHA-induced metabolic changes led to a marked decrease of intracellular ATP levels by 50% in both cancer cell lines, which mediated phosphorylation of metabolic stress marker, AMPK, at Thr172. These findings show that DHA contributes to impaired cancer cell growth and survival by altering cancer cell metabolism, increasing metabolic stress and altering HIF-1α-associated metabolism, while not affecting non-transformed MCF-10A cells. This study provides rationale for enhancement of current cancer prevention models and current therapies by combining them with dietary sources, like DHA.

An updated systemic review and meta-analysis on human papillomavirus in breast carcinogenesis.

Background: Breast Cancer (BC) stands out as the widely prevalent malignancy among all the types of cancer affecting women worldwide. There is significant evidence that the pathogenicity of BC may be altered by Human Papillomavirus (HPV) infection; however, conclusive data are not yet available. Methods: By searching five databases, including EMBASE, IBECS, PubMed, Scopus, Science Direct, Google Scholar, and Web of Science, a thorough systematic analysis was conducted on the prevalence of HPV in BC patients from 1990 to June 30, 2022. After applying extensive eligibility criteria, we selected 74 publications for further analysis based on the prevalence of HPV infections in breast tissues. All of the data were analyzed using a random-effects meta-analysis, Cochran Q test and I2 statistic were used to calculate the heterogeneity of the prevalence among these studies using subgroup analysis. Variations in the HPV prevalence estimates in different subgroups were evaluated by subgroup meta-analysis. Results: In total, 3156 studies were initially screened, resulting in 93 full-text studies reviewed, with 74 meeting inclusion criteria. Among a total of 7156 BC biopsies, the pool prevalence of HPV was 25.6% (95% CI= 0.24-0.33, τ2 = 0.0369 with significant heterogeneity between estimates (I 2 = 97% and p< 0.01). Consequently, 45 studies with available controls were further studied, and the prevalence of HPV in case-control studies was 26.2% with overall odds 5.55 (95% CI= 3.67-8.41, I 2 = 38%, τ2 = 1.4878, p< 0.01). Further subgroup analysis of HPV revealed HPV-16 had a maximum prevalence of 9.6% (95% CI= 3.06-11.86, I 2 = 0%, τ2 = 0.6111, p< 0.01). Among different geographical regions, Europe reported the maximum prevalence of HPV, i.e., 39.2% (95% CI=1.29-7.91, I 2 = 18%, τ2 = 1.2911, p< 0.01). Overall distribution showed HPV-18 was a frequent HPV subtype reported in Australia. Conclusion: Current study provides a global estimate of HPV prevalence in BC patients and demonstrates a significant association between this virus and BC etiology. Nevertheless, we recommend further investigation into the underlying mechanism is essential to validate this hypothesis.

Effect of Delphinidin on Metabolomic Profile in Breast Carcinogenesis.

BACKGROUND: Breast cancer is a malignant tumor which threat to women's physical and mental health. Delphinidin, one of the main anthocyanidins, has potent anti-cancer properties. In previous study, we found that delphinidin has the preventive role in MNU-induced breast carcinogenesis of rats, but the molecular mechanism by which delphinidin combats breast cancer has not been completely elucidated.The aim of the present study was to identify metabolic profile that account for delphinidin on the preventive effect on 1-methyl-1-nitrosourea (MNU)-induced breast carcinogenesis of rats. METHODS: In the present study, liquid chromatography-mass spectrometry (LC-MS) was conducted to identify metabolic profiles of rat tissues collected from normal mammary glands (normal group), breast tumors derived from MNU-induced breast carcinogenesis models (control group) and delphinidin administration models (delphinidin group). Principal component analysis (PCA) and partial least squares-discriminate analysis (PLS-DA) were employed to identify biochemical patterns. The values of variable importance in the projection (VIP) in PLS-DA model combined with the P value of Student's t-test were used to determine important metabolites. An orthogonal partial least square discriminant analysis (OPLS-DA) was used to conduct the supervised analysis. The fitness and prediction capabilities of PCA modes were measured by R 2 and Q 2 value respectively. Potential biomarkers were subjected to pathway analysis with Metaboanalyst 3.0 based on the KEGG Pathway Database to identify related metabolic pathways. RESULTS: The PCA and PLS-DA analysis indicated that the proposed method were satisfactory for metabolomic analysis. Metabolites from the obtained features were further filtered by PLS-DA analysis with VIP>1.0 and P<0.05. The significant difference was appeared in 190 metabolites between normal group and control group (P<0.05). Eight most significant metabolic pathways were obtained on the basis of the results of P<0.05 data analysis between control and normal group, embodying in aminoacyl-tRNA biosynthesis, arginine biosynthesis, biosynthesis of unsaturated fatty acids, valine, leucine and isoleucine biosynthesis, purine metabolism, alanine, aspartate and glutamate metabolism, glycerophospholipid metabolism, histidine metabolism. A total of 48 metabolites were identified to be associated with protective effects of delphinidin on MNU-induced rats significantly(P<0.05). Compared with control group, a total of 5 metabolic pathways were significantly perturbed in response to delphinidin administration (p<0.05), including in taurine and hypotaurine metabolism, Glycerophospholipid metabolism, arachidonic acid metabolism, aminoacyl-tRNA biosynthesis and primary bile acid biosynthesis. CONCLUSION: Metabolites and metabolic pathways were identified to be associated with protective effects of delphinidin on MNU-induced rats. The findings provided new insights into the precise mechanism of delphinidin in preventing breast carcinogenesis.

Geospatiotemporal and causal inference study of cannabis and other drugs as risk factors for female breast cancer USA 2003-2017.

Breast cancer (BC) is the commonest human cancer and its incidence (BC incidence, BCI) is rising worldwide. Whilst both tobacco and alcohol have been linked to BCI genotoxic cannabinoids have not been investigated. Age-adjusted state-based BCI 2003-2017 was taken from the Surveillance Epidemiology and End Results database of the Centers for Disease Control. Drug use from the National Survey of Drug Use and Health, response rate 74.1%. Median age, median household income and ethnicity were from US census. Inverse probability weighted (ipw) multivariable regression conducted in R. In bivariate analysis BCI was shown to be significantly linked with rising cannabis exposure {ß-est. = 3.93 [95% confidence interval 2.99, 4.87], P = 1.10 × 10-15}. At 8 years lag cigarettes:cannabis [ß-est. = 2660 (2150.4, 3169.3), P = 4.60 × 10-22] and cannabis:alcoholism [ß-est. = 7010 (5461.6, 8558.4), P = 1.80 × 10-17] were significant in ipw-panel regression. Terms including cannabidiol [CBD; ß-est. = 16.16 (0.39, 31.93), P = 0.446] and cannabigerol [CBG; ß-est. = 6.23 (2.06, 10.39), P = 0.0034] were significant in spatiotemporal models lagged 1:2 years, respectively. Cannabis-liberal paradigms had higher BCI [67.50 ± 0.26 v. 65.19 ± 0.21/100 000 (mean ± SEM), P = 1.87 × 10-11; ß-est. = 2.31 (1.65, 2.96), P = 9.09 × 10-12]. 55/58 expected values >1.25 and 13/58 >100. Abortion was independently and causally significant in space-time models. Data show that exposure to cannabis and the cannabinoids Δ9-tetrahydrocannabinol, CBD, CBG and alcoholism fulfil quantitative causal criteria for BCI across space and time. Findings are robust to adjustment for age and several known sociodemographic, socio-economic and hormonal risk factors and establish cannabinoids as an additional risk factor class for breast carcinogenesis. BCI is higher under cannabis-liberal legal paradigms.

Potential Mechanisms by which Glucocorticoids Induce Breast Carcinogenesis through Nrf2 Inhibition.

Breast cancer is the most common malignancy among women worldwide. Several studies indicate that, in addition to established risk factors for breast cancer, other factors such as cortisol release related to psychological stress and drug treatment with high levels of glucocorticoids may also contribute significantly to the initiation of breast cancer. There are several possible mechanisms by which glucocorticoids might promote neoplastic transformation of breast tissue. Among these, the least known and studied is the inhibition of the nuclear erythroid factor 2-related (Nrf2)-antioxidant/electrophile response element (ARE/EpRE) pathway by high levels of glucocorticoids. Specifically, Nrf2 is a potent transcriptional activator that plays a central role in the basal and inducible expression of many cytoprotective genes that effectively protect mammalian cells from various forms of stress and reduce the propensity of tissues and organisms to develop disease or malignancy including breast cancer. Consequently, a loss of Nrf2 in response to high levels of gluco-corticoids may lead to a decrease in cellular defense against oxidative stress, which plays an important role in the initiation of human mammary carcinogenesis. In the present review, we provide a comprehensive overview of the current state of knowledge of the cellular mechanisms by which both glucocorticoid pharmacotherapy and endogenous GCs (cortisol in humans and corticosterone in rodents) may contribute to breast cancer development through inhibition of the Nrf2-ARE/EpRE pathway and the protective role of melatonin against glucocorticoid-induced apoptosis in the immune system.

JFK Is a Hypoxia-Inducible Gene That Functions to Promote Breast Carcinogenesis.

Many carcinomas feature hypoxia, a condition has long been associated with tumor progression and poor prognosis, as well as resistance to chemoradiotherapy. Here, we report that the F-box protein JFK promotes mammary tumor initiation and progression in MMTV-PyMT murine model of spontaneous breast cancer. We find that JFK is inducible under hypoxic conditions, in which hypoxia-inducible factor HIF-1α binds to and transcriptionally activates JFK in breast cancer cells. Consistently, analysis of public clinical datasets reveals that the mRNA level of JFK is positively correlated with that of HIF-1α in breast cancer. We show that JFK deficiency leads to a decrease in HIF-1α-induced glycolysis in breast cancer and sensitizes hypoxic breast cancer cells to ionizing radiation and chemotherapeutic treatment. These results indicate that JFK is an important player in hypoxic response, supporting the pursuit of JFK as a potential therapeutic target for breast cancer intervention.

In vivo and in vitro studies evaluating the chemopreventive effect of metformin on the aryl hydrocarbon receptor-mediated breast carcinogenesis.

Metformin (MET) is a clinically used anti-hyperglycemic agent that shows activities against chemically-induced animal models of cancer. A study from our laboratory showed that MET protectes against 7, 12-dimethylbenz[a]anthracene (DMBA)-induced carcinogenesis in vitro human non-cancerous epithelial breast cells (MCF10A) via activation of the aryl hydrocarbon receptor (AhR). However, it is unclear whether MET can prevent the initiation of breast carcinogenesis in an in vivo rat model of AhR-induced breast carcinogenesis. Therefore, the main aims of this study are to examine the effect of MET on protecting against rat breast carcinogenesis induced by DMBA and to explore whether this effect is medicated through the AhR pathway. In this study, treatment of female rats with DMBA initiated breast carcinogenesis though inhibiting apoptosis and tumor suppressor genes while inducing oxidative DNA damage and cell cycle proliferative markers. This effect was associated with activation of AhR and its downstream target genes; cytochrome P4501A1 (CYP1A1) and CYP1B1. Importantly, MET treatment protected against DMBA-induced breast carcinogenesis by restoring DMBA effects on apoptosis, tumor suppressor genes, DNA damage, and cell proliferation. Mechanistically using in vitro human breast cancer MCF-7 cells, MET inhibited breast cancer stem cells spheroids formation and development by DMBA, which was accompanied by a proportional inhibition in CYP1A1 gene expression. In conclusion, the study reports evidence that MET is an effective chemopreventive therapy for breast cancer by inhibiting the activation of CYP1A1/CYP1B1 pathway in vivo rat model.

90 YEARS OF PROGESTERONE: Progesterone receptor signaling in the normal breast and its implications for cancer.

Progesterone is considered as the pregnancy hormone and acts on many different target tissues. Progesterone receptor (PR) signaling is important for normal development and the physiologic function of the breast and impinges on breast carcinogenesis. Both systemically and locally, in the breast epithelium, there are multiple layers of complexity to progesterone action, many of which have been revealed through experiments in mice. The hormone acts via its receptor expressed in a subset of cells, the sensor cells, in the breast epithelium with different signaling outcomes in individual cells eliciting distinct cell-intrinsic and paracrine signaling involving different mediators for different intercellular interactions. PR expression itself is developmentally regulated and the biological outcome of PR signaling depends on the developmental stage of the mammary gland and the endocrine context. During both puberty and adulthood PR activates stem and progenitor cells through Wnt4-driven activation of the myoepithelium with downstream Adamts18-induced changes in extracellualr matrix (ECM) / basal membrane (BM). During estrous cycling and pregnancy, the hormone drives a major cell expansion through Rankl. At all stages, PR signaling is closely tied to estrogen receptor α (ER) signaling. As the PR itself is a target gene of ER, the complex interactions are experimentally difficult to dissect and still poorly understood. Ex vivo models of the human breast and studies on biopsy samples show that major signaling axes are conserved across species. New intraductal xenograft models hold promise to provide a better understanding of PR signaling in the normal breast epithelium and in breast cancer development in the near future.

Mitochondria Autoimmunity and MNRR1 in Breast Carcinogenesis: A Review.

We review here the evidence for participation of mitochondrial autoimmunity in BC inception and progression and propose a new paradigm that may challenge the prevailing thinking in oncogenesis by suggesting that mitochondrial autoimmunity is a major contributor to breast carcinogenesis and probably to the inception and progression of other solid tumors. It has been shown that MNRR1 mediated mitochondrial-nuclear function promotes BC cell growth and migration and the development of metastasis and constitutes a proof of concept supporting the participation of mitochondrial autoimmunity in breast carcinogenesis. The resemblance of the autoantibody profile in BC detected by IFA with that in the rheumatic autoimmune diseases suggested that studies on the autoantibody response to tumor associated antigens and the characterization of the mtDNA- and nDNA-encoded antigens may provide functional data on breast carcinogenesis. We also review the studies supporting the view that a panel of autoreactive nDNA-encoded mitochondrial antigens in addition to MNRR1 may be involved in breast carcinogenesis. These include GAPDH, PKM2, GSTP1, SPATA5, MFF, ncRNA PINK1-AS/DDOST as probably contributing to BC progression and metastases and the evidence suggesting that DDX21 orchestrates a complex signaling network with participation of JUND and ATF3 driving chronic inflammation and breast tumorigenesis. We suggest that the widespread autoreactivity of mtDNA- and nDNA-encoded mitochondrial proteins found in BC sera may be the reflection of autoimmunity triggered by mitochondrial and non-mitochondrial tumor associated antigens involved in multiple tumorigenic pathways. Furthermore, we suggest that mitochondrial proteins may contribute to mitochondrial dysfunction in BC even if mitochondrial respiration is found to be within normal limits. However, although the studies show that mitochondrial autoimmunity is a major factor in breast cancer inception and progression, it is not the only factor since there is a multiplex autoantibody profile targeting centrosome and stem cell antigens as well as anti-idiotypic antibodies, revealing the complex signaling network involved in breast carcinogenesis. In summary, the studies reviewed here open new, unexpected therapeutic avenues for cancer prevention and treatment of patients with cancer derived from an entirely new perspective of breast carcinogenesis.

Dissecting the prevention of estrogen-dependent breast carcinogenesis through Nrf2-dependent and independent mechanisms.

Breast cancer is the most common malignancy among women worldwide. Various studies indicate that prolonged exposure to elevated levels of estrogens is associated with development of breast cancer. Both estrogen receptor-dependent and independent mechanisms can contribute to the carcinogenic effects of estrogens. Among them, the oxidative metabolism of estrogens plays a key role in the initiation of estradiol-induced breast cancer by generation of reactive estrogen quinones as well as the associated formation of oxygen free radicals. These genotoxic metabolites can react with DNA to form unstable DNA adducts which generate mutations leading to the initiation of breast cancer. A variety of endogenous and exogenous factors can alter estrogen homeostasis and generate genotoxic metabolites. The use of specific phytochemicals and dietary supplements can inhibit the risk of breast cancer not only by the modulation of several estrogen-activating enzymes (CYP19, CYP1B1) but also through the induction of various cytoprotective enzymes (eg, SOD3, NQO1, glutathione S-transferases, OGG-1, catechol-O-methyltransferases, CYP1B1A, etc.) that reestablish the homeostatic balance of estrogen metabolism via nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent and independent mechanisms.

Prevention of Breast Cancer by Natural Phytochemicals: Focusing on Molecular Targets and Combinational Strategy.

Starting from the 21st century, breast cancer can be classified as the most common invasive malignancy in women. Among the preventive or therapeutic strategies of breast cancer, combination therapy is the most promising approach. This mode of treatment of breast cancer concurrently maximizes efficacy, overcomes multidrug resistance, and minimizes harmful side effects caused by radiotherapy and chemotherapy alone. The risk of cancer can be reduced by supplementing diets with naturally occurring products known as phytochemicals. These phytochemicals have well-defined roles in the management of every stage of breast carcinogenesis. In this review, the collective data of dietary phytochemicals used to sensitize breast cancer cells to therapeutic approaches are reported and their specific molecular targets through synergistic, additive, and potentiation effects are highlighted. The concept of combining natural agents with medicines to augment therapeutic responses creates an optimal modality, which may facilitate clinical applications of combination regimens in the future.

Novel application of normalized pointwise mutual information (NPMI) to mine biomedical literature for gene sets associated with disease: use case in breast carcinogenesis.

Advances in technology within biomedical sciences have led to an inundation of data across many fields, raising new challenges in how best to integrate and analyze these resources. For example, rapid chemical screening programs like the US Environmental Protection Agency's ToxCast and the collaborative effort, Tox21, have produced massive amounts of information on putative chemical mechanisms where assay targets are identified as genes; however, systematically linking these hypothesized mechanisms with in vivo toxicity endpoints like disease outcomes remains problematic. Herein we present a novel use of normalized pointwise mutual information (NPMI) to mine biomedical literature for gene associations with biological concepts as represented by Medical Subject Headings (MeSH terms) in PubMed. Resources that tag genes to articles were integrated, then cross-species orthologs were identified using UniRef50 clusters. MeSH term frequency was normalized to reflect the MeSH tree structure, and then the resulting GeneID-MeSH associations were ranked using NPMI. The resulting network, called Entity MeSH Co-occurrence Network (EMCON), is a scalable resource for the identification and ranking of genes for a given topic of interest. The utility of EMCON was evaluated with the use case of breast carcinogenesis. Topics relevant to breast carcinogenesis were used to query EMCON and retrieve genes important to each topic. A breast cancer gene set was compiled through expert literature review (ELR) to assess performance of the search results. We found that the results from EMCON ranked the breast cancer genes from ELR higher than randomly selected genes with a recall of 0.98. Precision of the top five genes for selected topics was calculated as 0.87. This work demonstrates that EMCON can be used to link in vitro results to possible biological outcomes, thus aiding in generation of testable hypotheses for furthering understanding of biological function and the contribution of chemical exposures to disease.

Inhibitory Effect of Filipendula ulmaria on Mammary Carcinogenesis Induced by Local Administration of Methylnitrosourea to Target Organ in Rats.

BACKGROUND: The meadowsweet (Filipendula ulmaria (L.) Maxim.) may have a cancer prophylactic activity, since its extracts exhibit antioxidant, anti-inflammatory and other effects. We investigated the ability of a meadowsweet decoction to inhibit mammary carcinogenesis induced by intramammary injections of Methylnitrosourea (MNU) to the target organ in rats. MATERIALS AND METHODS: The chemical composition of meadowsweet extracts was studied by traditional methods. In animal experiments, adult outbred female rats received single injections of MNU at a dose 1mg directly into the tissue of each mammary gland. After carcinogenic exposure one group (MNU) of rats continued to receive standard feed and tap water throughout life. In another group (MNU+meadowsweet), rats were given daily a decoction of the meadowsweet instead of drinking water and standard feed. RESULTS: Meadowsweet extracts showed a sufficiently high content of flavonoids and tannins and also some individual phenolic compounds. In rats after injections of MNU the overall incidence of tumors was 90% with tumor multiplicity of 3.1. The majority of rats (86%) developed multiple malignant tumors of the mammary gland (most often adenocarcinomas). In rats from the group MNU+meadowsweet, there was a statistically significant decrease of the overall tumor multiplicity-by 1.5 times, and the incidence and multiplicity of breast tumors-by 1.6 and 2.2 times, respectively. CONCLUSIONS: Meadowsweet extract can be considered an effective inhibitor of breast carcinogenesis.

Retrospective methods to estimate radiation dose at the site of breast cancer development after Hodgkin lymphoma radiotherapy.

BACKGROUND: An increased risk of breast cancer following radiotherapy for Hodgkin lymphoma (HL) has now been robustly established. In order to estimate the dose-response relationship more accurately, and to aid clinical decision making, a retrospective estimation of the radiation dose delivered to the site of the subsequent breast cancer is required. METHODS: For 174 Dutch and 170 UK female patients with breast cancer following HL treatment, the 3-dimensional position of the breast cancer in the affected breast was determined and transferred onto a CT-based anthropomorphic phantom. Using a radiotherapy treatment planning system the dose distribution on the CT-based phantom was calculated for the 46 different radiation treatment field set-ups used in the study population. The estimated dose at the centre of the breast cancer, and a margin to reflect dose uncertainty were determined on the basis of the location of the tumour and the isodose lines from the treatment planning. We assessed inter-observer variation and for 47 patients we compared the results with a previously applied dosimetry method. RESULTS: The estimated median point dose at the centre of the breast cancer location was 29.75 Gy (IQR 5.8-37.2), or about 75% of the prescribed radiotherapy dose. The median dose uncertainty range was 5.97 Gy. We observed an excellent inter-observer variation (ICC 0.89 (95% CI: 0.74-0.95)). The absolute agreement intra-class correlation coefficient (ICC) for inter-method variation was 0.59 (95% CI: 0.37-0.75), indicating (nearly) good agreement. There were no systematic differences in the dose estimates between observers or methods. CONCLUSION: Estimates of the dose at the point of a subsequent breast cancer show good correlation between methods, but the retrospective nature of the estimates means that there is always some uncertainty to be accounted for.