The impact of endocrine disrupting compounds and carcinogens in wastewater: Implications for breast cancer.

The incidence of breast cancer is often associated with geographic variation which indicates that a person's surrounding environment can be an important etiological factor in cancer development. Environmental risk factors can include exposure to sewage- or wastewater, which consist of a complex mixture of pathogens, mutagens and carcinogens. Wastewater contains primarily carbonaceous, nitrogenous and phosphorus compounds, however it can also contain trace amounts of chemical pollutants including toxic metal cations, hydrocarbons and pesticides. More importantly, the contamination of drinking water by wastewater is a potential source of exposure to mammary carcinogens and endocrine disrupting compounds. Organic solvents and other pollutants often found in wastewater have been detected in various tissues, including breast and adipose tissues. Furthermore, these pollutants such as phenolic compounds in some detergents and plastics, as well as parabens and pesticides can mimic estrogen. High estrogen levels are a well-established risk factor for estrogen-receptor (ER) positive breast cancer. Therefore, exposure to wastewater is a risk factor for the initiation, progression and metastasis of breast cancer. Carcinogens present in wastewater can promote tumourigenesis through various mechanisms, including the formation of DNA adducts, gene mutations and oxidative stress. Lastly, the presence of endocrine disrupting compounds in wastewater can have negative implications for ER-positive breast cancers, where these molecules can activate ERα to promote cell proliferation, survival and metastasis. As such, strategies should be implemented to limit exposure, such as providing funding into treatment technologies and implementation of regulations that limit the production and use of these potentially harmful chemicals.

The effect of HIF-1α inhibition in breast cancer cells prior to doxorubicin treatment under conditions of normoxia and hypoxia.

BACKGROUND: Oxygen deprivation is a key hallmark within solid tumours that contributes to breast-tumour pathophysiology. Under these conditions, neoplastic cells activate several genes, regulated by the HIF-1 transcription factor, which alters the tumour microenvironment to promote survival - including resistance to cell death in therapeutic attempts such as doxorubicin (Dox) treatment. METHODS: We investigated HIF-1ɑ as a therapeutic target to sensitize breast cancer cells to Dox treatment. Under both normoxic (21% O2) and hypoxic (∼0.1% O2) conditions, the HIF-1 inhibitor, 2-methoxyestradiol (2-ME), was investigated as an adjuvant for its ability to alter MCF-7 cell viability, apoptosis, autophagy and molecular pathways which are often associated with increased cell survival. RESULTS: Here we observed that an inverse relationship between HIF-1ɑ and apoptosis exists and that Dox promotes autophagy under hypoxic conditions. Although adjuvant therapy with 2-ME induced an antagonistic effect in breast cancer cells, upregulated HIF-1ɑ expression in a hypoxic environment promotes treatment resistance and this was attenuated once HIF-1ɑ gene expression was silenced. CONCLUSION: Therefore, highlighting the identification of possible hypoxia-targeting therapies for breast cancer patients can be beneficial by promoting more favourable treatment responses.

The impact of mitochondria on cancer treatment resistance.

BACKGROUND: The ability of cancer cells to develop treatment resistance is one of the primary factors that prevent successful treatment. Although initially thought to be dysfunctional in cancer, mitochondria are significant players that mediate treatment resistance. Literature indicates that cancer cells reutilize their mitochondria to facilitate cancer progression and treatment resistance. However, the mechanisms by which the mitochondria promote treatment resistance have not yet been fully elucidated. CONCLUSIONS AND PERSPECTIVES: Here, we describe various means by which mitochondria can promote treatment resistance. For example, mutations in tricarboxylic acid (TCA) cycle enzymes, i.e., fumarate hydratase and isocitrate dehydrogenase, result in the accumulation of the oncometabolites fumarate and 2-hydroxyglutarate, respectively. These oncometabolites may promote treatment resistance by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, inhibiting the anti-tumor immune response, or promoting angiogenesis. Furthermore, stromal cells can donate intact mitochondria to cancer cells after therapy to restore mitochondrial functionality and facilitate treatment resistance. Targeting mitochondria is, therefore, a feasible strategy that may dampen treatment resistance. Analysis of tumoral DNA may also be used to guide treatment choices. It will indicate whether enzymatic mutations are present in the TCA cycle and, if so, whether the mutations or their downstream signaling pathways can be targeted. This may improve treatment outcomes by inhibiting treatment resistance or promoting the effectiveness of anti-angiogenic agents or immunotherapy.

Serum amyloid A and inflammasome activation: A link to breast cancer progression?

Breast cancer is the most frequently diagnosed cancer in women globally. Although there have been many significant advances made in the diagnosis and treatment of breast cancer, numerous unresolved challenges remain, which include prevention, early diagnosis, metastasis and recurrence. The role of inflammation in cancer development is well established and is believed to be one of the leading hallmarks of cancer progression. Recently, the role of the inflammasome, a cytosolic multiprotein complex, has received attention in different cancers. By contributing to the activation of inflammatory cytokines the inflammasome intensifies the inflammatory cascade. The inflammasome can be activated through several pathways, which include the binding of pattern associated molecular patterns (PAMPs) and damage associated molecular patterns (DAMPs) to toll-like receptors (TLRs). Serum amyloid A (SAA), a non-specific acute-phase protein, can function as an endogenous DAMP by binding to pattern recognition receptors like TLRs on both breast cancer cells and cancer associated fibroblasts (CAFs). SAA can thus stimulate the production of IL-1ß, thereby creating a favourable inflammatory environment to support tumour growth. The aim of this review is to highlight the possible role of SAA as an endogenous DAMP in the tumour microenvironment (TME) thereby promoting breast cancer growth through the activation of the NLRP3 inflammasome.

Vascular function and cardiovascular risk in a HIV infected and HIV free cohort of African ancestry: baseline profile, rationale and methods of the longitudinal EndoAfrica-NWU study.

BACKGROUND: People living with the Human Immunodeficiency Virus (PLHIV) have an increased susceptibility to develop non-communicable diseases such as cardiovascular disease (CVD). Infection with HIV contributes to the development of CVD independent of traditional risk factors, with endothelial dysfunction being the central physiological mechanism. While HIV-related mortality is declining due to antiretroviral treatment (ART), the number of deaths due to CVD is rising in South Africa - the country with the highest number of PLHIV and the world's largest ART programme. The EndoAfrica study was developed to determine whether HIV infection and ART are associated with cardiovascular risk markers and changes in vascular structure and function over 18 months in adults from different provinces of South Africa. This paper describes the rationale, methodology and baseline cohort profile of the EndoAfrica study conducted in the North West Province, South Africa. METHODS: In this case-control study, conducted between August 2017 and June 2018, 382 volunteers of African descent (276 women; 106 men), comprising of 278 HIV infected and 104 HIV free individuals were included. We measured health behaviours, a detailed cardiovascular profile, and performed biomarker analyses. We compared baseline characteristics, blood pressure, vascular function and biochemical markers between those infected and HIV free. RESULTS: At baseline, the HIV infected participants were older (43 vs 39 years), less were employed (21% vs 40%), less had a tertiary education (7% vs 16%) and their body mass index was lower (26 vs 29 kg/m2) than that of the HIV free participants. While the cardiovascular profile, flow-mediated dilation and pulse wave velocity did not differ, glycated haemoglobin was lower (p = 0.017) and total cholesterol, high density lipoprotein cholesterol, triglycerides, gamma-glutamyltransferase and tobacco use were higher (all p < 0.047) in PLHIV. CONCLUSION: Despite PLHIV being older, preliminary cross-sectional analysis suggests that PLHIV being treated with ART do not have poorer endothelial or vascular function compared to the HIV free participants. More detailed analyses on the baseline and follow-up data will provide further clarity regarding the cardiovascular profile of South Africans living with HIV.

The paracrine effects of fibroblasts on Doxorubicin-treated breast cancer cells.

Breast cancer is frequently diagnosed in women and poses a major health problem throughout the world. Currently, the unresponsiveness of cancer cells to chemotherapeutics is a major concern. During chemotherapeutic treatment with Doxorubicin, neighbouring cells in the tumor microenvironment are also damaged. Depending on the concentration of Doxorubicin, apoptotic or senescent fibroblasts in the tumor microenvironment can then secrete a variety of bioactive molecules which promote tumor growth, metastasis and drug resistance. Mouse embryonic fibroblasts (MEFs) were treated with Doxorubicin to induce apoptosis and senescence respectively. Conditioned media was collected from the MEFs and was used to assess the paracrine effects between fibroblasts and E0771 murine breast cancer cells. Senescent fibroblasts significantly increased cell viability in E0771 cells following Doxorubicin treatment by activating Akt and ERK. Autophagy contributed to cancer cell death and not to treatment resistance in breast cancer cells. Our results highlight the complexity of the tumor microenvironment where chemotherapeutic agents such as Doxorubicin can induce significant changes fibroblasts which can affect tumor growth via the secretion of paracrine factors. Here we have demonstrated that those secreted paracrine factors enhance breast cancer growth and induce therapeutic resistance through the evasion of apoptotic cell death.

A health profile associated with excessive alcohol use independently predicts aortic stiffness over 10 years in black South Africans.

OBJECTIVE: Black populations exhibit higher arterial stiffness than whites and suffer a disproportionate burden of cardiovascular disease. It is therefore important to identify modifiable health behaviours predicting large artery stiffness in blacks. We examined whether traditional cardiovascular risk factors and health behaviours of black South Africans predict large artery stiffness 10 years later. METHODS: We included 650 HIV-free participants (32.8% men) and collected data in rural and urban areas of the North West Province in 2005 and 2015. We collected questionnaire data, anthropometry, blood pressure and determined cardiometabolic and inflammatory markers from blood samples. We measured carotid-femoral pulse wave velocity (PWV) at follow-up. RESULTS: A total of 25.3% of our population, aged 65 ±â€Š9.57 years, had a PWV exceeding 10 m/s. In multivariable-adjusted regression analyses, the strongest predictors of PWV were mean arterial pressure, age and heart rate (all P < 0.024). Urban locality (R = 0.31, ß = 0.12, P = 0.001), self-reported alcohol use (ß = 0.11, P = 0.018) and plasma glucose (ß = 0.08 P = 0.023) associated positively with PWV at follow-up. We found a negative association between PWV and BMI (ß = -0.15, P = 0.001), and no associations with sex, smoking, inflammatory markers, lipids, liver enzymes or antihypertensive medication. When replacing self-reported alcohol with gamma-glutamyltransferase, the latter associated positively with PWV (ß = 0.09, P = 0.023). CONCLUSION: A health profile associated with excessive alcohol use, including an urban setting, elevated plasma glucose and lower BMI predicts large artery stiffness independently of age and blood pressure in black South Africans over 10 years. This observation prompts urgent public health strategies to target alcohol overuse.

Monocyte Chemoattractant Protein-1 and Large Artery Structure and Function in Young Individuals: The African-PREDICT Study.

To better understand hypertension development, the authors determined whether monocyte chemoattractant protein-1 (MCP-1) is associated with arterial stiffness (pulse wave velocity [PWV]) and carotid intima-media wall thickness (cIMT) in a young apparently healthy black and white population (N=403, aged 20-30 years). Carotid-femoral PWV, central systolic blood pressure, and cIMT were measured, and MCP-1, reactive oxygen species, inflammatory markers (interleukin 6, tumor necrosis factor α), and endothelial activation (intercellular adhesion molecule, vascular cell adhesion molecule) were determined from blood samples. Although carotid-femoral PWV and cIMT were similar between blacks and whites, black men and women showed higher central systolic blood pressure, MCP-1, and reactive oxygen species than whites (all P<.05). In addition, black women had higher brachial blood pressure and interleukin 6 (all P<.001). A consistent positive association only in black women between cIMT and MCP-1 in multiple regression analyses was found (R²=0.151, ß=0.248; P=.021). In this model, cIMT was also independently associated with vascular cell adhesion molecule (ß=0.251; P=.022). The authors found elevated central systolic blood pressure and MCP-1 in young blacks, where cIMT was independently associated with MCP-1 in black women.

Large artery stiffness is associated with gamma-glutamyltransferase in young, healthy adults: The African-PREDICT study.

Increased arterial stiffness is linked to cardiovascular disease development, particularly in black populations. Since detrimental health behaviors in young adults may affect arterial stiffness, we determined whether arterial stiffness associates with specific health behaviors, and whether it is more pronounced in young healthy black compared to white adults. We included 373 participants (49% black, 42% men) aged 20-30 years. Mean arterial pressure was higher for blacks than whites (P < .001), but carotid-femoral pulse wave velocity was similar (6.37 vs. 6.36 m/s; P = .89) after adjustment for mean arterial pressure. The black group had higher gamma-glutamyltransferase (GGT) (P < .001), cotinine, reactive oxygen species, interleukin-6, and monocyte-chemoattractant protein-1 (all P ≤ .017). Pulse wave velocity related positively and independently to GGT in both groups before and after multiple adjustments (both ß = 0.15; P ≤ .049). Blacks had an unfavorable vascular profile and higher GGT, possibly indicating a higher vulnerability to cardiovascular disease development, including changes in arterial stiffness. However, this observation needs confirmation.

Soluble urokinase plasminogen activator receptor as a prognostic marker of all-cause and cardiovascular mortality in a black population.

BACKGROUND: Elevated inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) are well-known risk factors for cardiovascular mortality. The less familiar marker, soluble urokinase plasminogen activator receptor (suPAR), is known to predict cancer, infections and all-cause mortality. We determined whether suPAR, CRP and IL-6 are predictive of both all-cause and cardiovascular mortality in a black population, highly burdened by cardiovascular disease and HIV infection. METHODS: We included 1425 black South Africans, of which 208 died within five years after baseline data collection. EDTA plasma biomarker levels were determined, while all-cause and cardiovascular mortality were used as endpoints. RESULTS: At baseline suPAR, CRP and IL-6 were higher in non-survivors than in survivors (P<0.001). SuPAR (HR 1.27, 95% CI 1.09-1.48), IL-6 (HR 1.49, 95% CI 1.24-1.78) and CRP (HR 1.39, 95% CI 1.17-1.65) predicted all-cause mortality, while only suPAR (HR 1.40, 95% CI 1.04-1.87) and IL-6 (HR 1.61, 95% CI 1.10-2.35) predicted cardiovascular mortality. The prognostic value of suPAR was independent of IL-6 and CRP (P≤0.015). CONCLUSION: SuPAR predicted both all-cause and cardiovascular mortality, independent of traditional risk factors, HIV and other inflammatory markers, underlining the prognostic value of suPAR in a black population.

Associations of suPAR with lifestyle and cardiometabolic risk factors.

BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR), a novel indicator of low-grade inflammation, is associated with cardiovascular disease and mortality in the general population, while an unhealthy lifestyle influences inflammatory status. We aimed to explore the relationship of suPAR with lifestyle and cardiometabolic risk factors in a black South African population. DESIGN: This cross-sectional study includes 1068 men and women (56·4 ± 10·1 years) from the North West province who took part in the South African leg of the Prospective Urban and Rural Epidemiology (PURE) study in 2010. Captured data included a detailed lifestyle profile (tobacco use, alcohol consumption, physical activity, psychological and dietary intake status), biochemical analyses (suPAR, C-reactive protein (CRP), glucose and lipids), as well as cardiovascular and anthropometric measurements. RESULTS: In exploratory analyses, we observed positive relationships between suPAR and lifestyle factors, such as tobacco use (P-trend < 0·001), both alcohol consumption (P-trend = 0·001) and γ-glutamyl transferase (GGT) (P-trend < 0·001) and unemployment (P-trend = 0·002). suPAR and CRP correlated significantly (r = 0·23; P < 0·001). These relationships were confirmed in multiple regression analyses as suPAR independently associated with tobacco use (ß = 0·13; P < 0·001), GGT (ß = 0·24; P < 0·001) and unemployment (ß = 0·07; P = 0·039). suPAR did not associate with the cardiometabolic factors glucose, lipids, blood pressure or measures of adiposity. CONCLUSION: suPAR was independently associated with unhealthy lifestyle behaviours, but not with cardiometabolic risk factors suggesting that suPAR, as known predictor of cardiovascular disease and mortality, is augmented by modifiable cardiovascular risk factors. These findings emphasise the need for a healthy lifestyle to decrease the burden of cardiovascular disease in Africans.

Low testosterone and hyperkinetic blood pressure responses in a cohort of South African men: the SABPA Study.

Hypertension (HT) and the metabolic syndrome are major problems in Africa. The role of sex hormones in the cardiovascular profile of black Africans in South Africa has not been studied. Our objective was to study the association between the sex hormones and ambulatory blood pressure and the heart rate (HR) in black and white South Africans. The 24-hour ambulatory blood pressure measurements were performed and the blood samples were taken between 07:00 and 09:00 hours. A total of 80 black and 98 white South African teachers between 25 and 65 years of age from similar socioeconomic backgrounds from the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study were included. As a result, a more vulnerable cardiovascular profile was observed in Africans compared with Caucasians. In the African group, low testosterone (T) explained 19%-36% of the variance in systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR, whereas in the Caucasian group non-sex-hormone-binding globulin (non-SHBG)-bound T explained 27% of the variance in HR. In the African males, inverse associations between blood pressure and T (SBP: P = .08; DBP: P = .02) and non-SHBG-bound T (SBP: P < .001; DBP: P < .01) and HR (P < 0.01) were observed. Ambulatory HR predicted a prediabetic state in Africans. In conclusion, low T levels may predispose or result in impaired cardiovascular function in African men. The possibility exists that a prediabetic state, vagal-impaired HR, and hyperkinetic blood pressure responses may predispose or result in low T levels in African men.

Sex hormones associated with subclinical kidney damage and atherosclerosis in South African men: the SABPA study.

BACKGROUND: Hypertension and increased blood glucose are associated with subclinical kidney damage, atherosclerosis and with low testosterone values. Low testosterone in men is often accompanied by increased levels of estradiol. OBJECTIVES AND METHODS: In this study, the association between estradiol, subclinical kidney damage and atherosclerosis in African and white men in a South African cohort was investigated. Cardiovascular variables were studied by means of B-mode ultrasound and ambulatory blood pressure (BP) monitoring. The sex hormones and other biochemical values were measured from fasting venous blood and overnight urine samples. The ethnic groups were stratified into low and high testosterone groups by means of median split. RESULTS: The low testosterone African group demonstrated a higher cardiovascular risk compared with the low testosterone white men with 91% being hypertensive and having increased albumin-to-creatinine ratio (ACR), left carotid intima-media thickness (L-CIMTf) and estradiol-to-testosterone ratio. In the low-testosterone African men, estradiol explained 33% of the variance in ACR, whereas the estradiol-to-testosterone ratio explained 22% of the variance in L-CIMTf, respectively. Estradiol-to-testosterone ratio was positively associated with ACR in the low testosterone whites. CONCLUSION: We conclude that increased levels of estradiol may play a role in the development of subclinical kidney damage in both African and white men as well as atherosclerosis in low-testosterone African men.

Blood glutathione and subclinical atherosclerosis in African men: the SABPA Study.

BACKGROUND: Sub-Saharan Africans face an increasing burden of hypertension and related cardiac and cerebrovascular morbidity and mortality, making the identification of factors leading to early vascular abnormalities imperative. METHODS: We investigated the possible influence of the antioxidant glutathione (GSH) on early subclinical atherosclerosis in 63 hypertensive (aged 45.2 years) and 34 normotensive (aged 38.9 years; P < 0.001) nondiabetic African men. We measured ambulatory daytime systolic and diastolic blood pressure (SBP, DBP) as well as daytime mean arterial pressure (MAP), carotid intima-media thickness (CIMT), and calculated the cross-sectional wall area. We determined the reduced form of GSH in whole blood and blood glucose in serum. RESULTS: Blood glucose (110 vs. 92 mg/dl; P < 0.001) and CIMT (0.75 vs. 0.61 mm; P < 0.001) were higher in hypertensives compared to normotensives. No significant difference existed for GSH. Associations in normotensives suggested the hypotensive effect of GSH after single (SBP: r = -0.35, P < or = 0.05; DBP: r = -0.37, P < or = 0.05; MAP: r = -0.38, P < or = 0.05) and multiple (SBP: B = -0.015, P < 0.05; DBP: B = -0.011, P < 0.05; MAP: B = -0.012, P < 0.05) regression analyses. In hypertensives, CIMT (B = -0.00027, P < 0.01) and cross-sectional wall area (CSWA) (B = -0.0066, P < 0.05) correlated negatively with GSH. These findings were consistent after excluding 10 human immunodeficiency virus (HIV)-positive hypertensive subjects. CONCLUSIONS: In hypertensive African men, CIMT is negatively associated with GSH, suggesting a possible contributory role of attenuated GSH levels in the development of subclinical atherosclerosis.