1,273 research outputs found
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Breast cysts and aluminium-based antiperspirant salts
On the basis that aluminium-based antiperspirant salts are designed to block apocrine sweat ducts of the axilla, and that breast cysts result from blocked breast ducts in the adjacent region of the body, it has been proposed that breast cysts may arise from antiperspirant use if sufficient aluminium is absorbed into breast tissues over long-term usage. This review collates evidence that aluminium can be absorbed from dermal application of antiperspirant salts and describes studies measuring levels of aluminium in breast tissues, including in breast cyst fluids. It is notable that breast cysts, as for breast cancers, start most frequently in the upper outer quadrant of the breast, which is the region closest to the site of underarm antiperspirant application. Mechanistic evidence is reviewed for a link between aluminium levels in breast tissue, cyst formation and development of breast cancer. If excessive use of antiperspirant is a cause of breast cysts, then reduction or cessation of use could provide a preventative or even treatment strategy. Furthermore, if cyst formation from antiperspirant use is an indicator of increased risk for breast cancer, then reduction in use of antiperspirant could also provide a strategy for reducing breast cancer risk
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Overview of air pollution and endocrine disorders
Over recent years, many environmental pollutant chemicals have been shown to possess the ability to interfere in the functioning of the endocrine system and have been termed endocrine disrupting chemicals. These compounds exist in air as volatile or semi-volatile compounds in the gas phase or attached to particulate matter. They include components of plastics (phthalates, bisphenol A), components of consumer goods (parabens, triclosan, alkyl phenols, fragrance compounds, organobromine flame retardants, fluorosurfactants), industrial chemicals (polychlorinated biphenyls), products of combustion (polychlorinated dibenzodioxins/ furans, polyaromatic hydrocarbons), pesticides, herbicides and some metals. This review summarises current knowledge concerning the sources of endocrine disrupting chemicals in air, measurements of levels of endocrine disrupting chemicals in air and the potential for adverse effects of endocrine disrupting chemicals in air on human endocrine health
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The potential for estrogen disrupting chemicals to contribute to migration, invasion and metastasis of human breast cancer cells
Estrogen disrupting chemicals are environmental compounds which mimic, antagonize or interfere in the action of
physiological estrogens. They occur naturally (plant phytoestrogens) but the majority are man-made compounds,
which, through their use in agricultural, industrial and consumer products, have become widely present in human
tissues including breast tissue. Since exposure to estrogen is a risk factor for breast cancer, estrogen disrupting chemicals may also contribute to breast cancer development. This review discusses evidence implicating estrogen disrupting chemicals in increasing migratory and invasive activity of breast epithelial cells, in epithelial-to-mesenchymal transition, and in growth of breast tumours at metastatic sites as well as the primary site. Mechanisms may be through the ability of such chemicals to bind to estrogen receptors, but unlike for proliferation, effects on cell migration and invasion are not limited to estrogen receptor-mediated mechanisms. Furthermore, whilst effects on proliferation can be measured within hours/days of adding an estrogen disrupting chemical to estrogen-responsive breast cancer cells, effects on cell migration occur after longer times (weeks). Most studies have focused on individual chemicals, but there is now a need to consider the environmentally relevant effects of long-term, low-dose
exposure to complex mixtures of estrogen disrupting chemicals on mechanisms of metastasis
Anti-Microbial Dendrimers against Multidrug-Resistant P. aeruginosa Enhance the Angiogenic Effect of Biological Burn-wound Bandages.
Multi-drug resistant Pseudomonas aeruginosa has increased progressively and impedes further regression in mortality in burn patients. Such wound infections serve as bacterial reservoir for nosocomial infections and are associated with significant morbidity and costs. Anti-microbial polycationic dendrimers G3KL and G3RL, able to kill multi-drug resistant P. aeruginosa, have been previously developed. The combination of these dendrimers with a class of biological bandages made of progenitor skin cells, which secrete growth factors, could positively impact wound-healing processes. However, polycations are known to be used as anti-angiogenic agents for tumor suppression. Since, neovascularization is pivotal in the healing of deep burn-wounds, the use of anti-microbial dendrimers may thus hinder the healing processes. Surprisingly, we have seen in this study that G3KL and G3RL dendrimers can have angiogenic effects. Moreover, we have shown that a dendrimer concentration ranging between 50 and 100 μg/mL in combination with the biological bandages can suppress bacterial growth without altering cell viability up to 5 days. These results show that antimicrobial dendrimers can be used in combination with biological bandages and could potentially improve the healing process with an enhanced angiogenesis
Mind the gap: Can we explain declining male reproductive health with known antiandrogens?
This article has been made available through the Brunel Open Access Publishing Fund.Several countries have experienced rises in cryptorchidisms, hypospadias and testicular germ cell cancer. The reasons for these trends are largely unknown, but Skakkebaek has proposed that these disorders form a testicular dysgenesis syndrome and can be traced to androgen insufficiency in foetal life. This suggests that antiandrogenic chemicals might contribute to risks, but few chemicals have been linked to these diseases in epidemiological studies. In animal studies with p,p0-dichlorodiphenyldichloroethylene, effects typical of disruptions of male sexual differentiation became apparent when the foetal levels of this androgen receptor (AR) antagonist approached values associated with responses in in vitro assays. This prompted us to analyse whether the 22 chemicals with AR antagonistic properties would produce mixture effects in an in vitro AR antagonism assay when combined at concentrations found in human serum. Other antiandrogenic modalities could not be considered. Two scenarios were investigated, one representative of average serum levels reported in European countries, the other in line with levels towards the high exposures. In both situations, the in vitro potency of the 22 selected AR antagonists was too low to produce combined AR antagonistic effects at the concentrations found in human serum, although the high exposure scenario came quite close to measurable effects. Nevertheless, our analysis exposes an explanation gap which can only be bridged by conjuring up as yet undiscovered high potency AR antagonists or, alternatively, high exposures to unknown agents of average potency
Replicating viral vector platform exploits alarmin signals for potent CD8+ T cell-mediated tumour immunotherapy
Viral infections lead to alarmin release and elicit potent cytotoxic effector
T lymphocyte (CTLeff) responses. Conversely, the induction of protective
tumour-specific CTLeff and their recruitment into the tumour remain
challenging tasks. Here we show that lymphocytic choriomeningitis virus (LCMV)
can be engineered to serve as a replication competent, stably-attenuated
immunotherapy vector (artLCMV). artLCMV delivers tumour-associated antigens to
dendritic cells for efficient CTL priming. Unlike replication-deficient
vectors, artLCMV targets also lymphoid tissue stroma cells expressing the
alarmin interleukin-33. By triggering interleukin-33 signals, artLCMV elicits
CTLeff responses of higher magnitude and functionality than those induced by
replication-deficient vectors. Superior anti-tumour efficacy of artLCMV
immunotherapy depends on interleukin-33 signalling, and a massive CTLeff
influx triggers an inflammatory conversion of the tumour microenvironment. Our
observations suggest that replicating viral delivery systems can release
alarmins for improved anti-tumour efficacy. These mechanistic insights may
outweigh safety concerns around replicating viral vectors in cancer
immunotherapy
Integrative analyses identify modulators of response to neoadjuvant aromatase inhibitors in patients with early breast cancer
Introduction
Aromatase inhibitors (AIs) are a vital component of estrogen receptor positive (ER+) breast cancer treatment. De novo and acquired resistance, however, is common. The aims of this study were to relate patterns of copy number aberrations to molecular and proliferative response to AIs, to study differences in the patterns of copy number aberrations between breast cancer samples pre- and post-AI neoadjuvant therapy, and to identify putative biomarkers for resistance to neoadjuvant AI therapy using an integrative analysis approach.
Methods
Samples from 84 patients derived from two neoadjuvant AI therapy trials were subjected to copy number profiling by microarray-based comparative genomic hybridisation (aCGH, n = 84), gene expression profiling (n = 47), matched pre- and post-AI aCGH (n = 19 pairs) and Ki67-based AI-response analysis (n = 39).
Results
Integrative analysis of these datasets identified a set of nine genes that, when amplified, were associated with a poor response to AIs, and were significantly overexpressed when amplified, including CHKA, LRP5 and SAPS3. Functional validation in vitro, using cell lines with and without amplification of these genes (SUM44, MDA-MB134-VI, T47D and MCF7) and a model of acquired AI-resistance (MCF7-LTED) identified CHKA as a gene that when amplified modulates estrogen receptor (ER)-driven proliferation, ER/estrogen response element (ERE) transactivation, expression of ER-regulated genes and phosphorylation of V-AKT murine thymoma viral oncogene homolog 1 (AKT1).
Conclusions
These data provide a rationale for investigation of the role of CHKA in further models of de novo and acquired resistance to AIs, and provide proof of concept that integrative genomic analyses can identify biologically relevant modulators of AI response
DMXL2 drives epithelial to mesenchymal transition in hormonal therapy resistant breast cancer through Notch hyper-activation
The acquisition of endocrine therapy resistance in estrogen receptor a (ERa) breast cancer patients represents a major clinical problem. Notch signalling has been extensively linked to breast cancer especially in patients who fail to respond to endocrine therapy. Following activation, Notch intracellular domain is released and enters the nucleus where activates transcription of target genes. The numerous steps that cascade after activation of the receptor complicate using Notch as biomarker. Hence, this warrants the development of reliable indicators of Notch activity. DMXL2 is a novel regulator of Notch signalling not yet investigated in breast cancer. Here, we demonstrate that DMXL2 is overexpressed in a subset of endocrine therapy resistant breast cancer cell lines where it promotes epithelial to mesenchymal transition through hyper-activation of Notch signalling via V-ATPase dependent acidification. Following DMXL2 depletion or treatment with Bafilomycin A1, both EMT targets and Notch signalling pathway significantly decrease. We show for the first time that DMXL2 protein levels are significantly increased in ERa positive breast cancer patients that progress after endocrine therapy. Finally, we demonstrate that DMXL2 is a transmembrane protein with a potential extra-cellular domain. These findings identify DMXL2 as a novel, functional biomarker for ERa positive breast cancer
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
Hydrophobically directed aldol reactions: polystyrene-supported L-proline as a recyclable catalyst for direct asymmetric aldol reactions in the presence of water
A simple synthetic methodology for the preparation of a polystyrene-
supported L-proline material is reported, and this
material has been used as catalyst in direct asymmetric aldol
reactions between several ketones and arylaldehydes to furnish
aldol products in high yields and stereoselectivities.
Screening of solvents showed that these reactions take place
only in the presence of water or methanol, at lower levels of
conversion in the latter case. This solvent effect, coupled
with the observed high stereoselectivities, has been ex-
Introduction
In the last decade organocatalysis has became a field of
great interest.[1] Organocatalysts are metal-free small organic
molecules that are able to function as efficient and
selective catalysts for a large variety of enantioselective
transformations. In this context, -proline and its derivatives
have emerged as powerful organocatalysts.[2] -Proline
can be regarded as the simplest “enzyme” and it has been
successfully applied in many reactions, such as Robinson
annulations,[3] aldol reactions,[4] Mannich reactions,[5]
Michael reactions,[6] direct electrophilic α-aminations,[7] Diels–
Alder reactions,[8] Baylis–Hillman reactions,[9] aza-Morita-
Baylis–Hillman reactions,[10] α-selenenylation,[11] oxidation,[
12] chlorination,[13] and others.[14]
Among all these processes, -proline-mediated aldol reactions
affording β-hydroxy ketones have been investigated
in great depth. Indeed, the aldol reaction is one of the most
important C–C bond-formation methods in organic synthesis.[
15] Proline and its derivatives operate by bifunctional catalysis
and play the role of a simplified version of the type I
[a] Dipartimento di Chimica Organica “E.Paternò”, Università di
Palermo,
Viale delle Scienze, Pad. 17, 90128 Palermo, Italy
Fax: +39-091-596825
E-mail: [email protected]
© 2007 Wiley-VCH Verlag GmbH 4688 & Co. KGaA, Weinheim Eur. J. Org. Chem. 2007, 4688–4698
plained in terms of the formation of a hydrophobic core in
the inner surface of the resin, whereas the hydrophilic proline
moiety lies at the resin/water interface. Such a microenvironment
both promotes the aldol reaction and increases the
stereoselectivity. Recycling investigations have shown that
this material can be reused, without loss in levels of conversion
and stereoselectivity, for at least five cycles
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