Estrogen matters in metastasis

Chronic Exposure to Low Levels of Parabens Increases Mammary Cancer Growth and Metastasis in Mice

Methylparaben (MP) and propylparaben (PP) are commonly used as food, cosmetic, and drug preservatives. These parabens are detected in the majority of US women and children, bind and activate estrogen receptors (ER), and stimulate mammary tumor cell growth and invasion in vitro. Hemizygous B6.FVB-Tg (MMTV-PyVT)634Mul/LellJ female mice (n = 20/treatment) were exposed to MP or PP at levels within the US Food and Drug Administration's "human acceptable daily intake." These paraben-exposed mice had increased mammary tumor volume compared with control mice (P < 0.001) and a 28% and 91% increase in the number of pulmonary metastases per week compared with the control mice, respectively (P < 0.0001). MP and PP caused differential expression of 288 and 412 mammary tumor genes, respectively (false discovery rate < 0.05), a subset of which has been associated with human breast cancer metastasis. Molecular docking and luciferase reporter studies affirmed that MP and PP bound and activated human ER, and RNA-sequencing revealed increased ER expression in mammary tumors among paraben-exposed mice. However, ER signaling was not enriched in mammary tumors. Instead, both parabens strongly impaired tumor RNA metabolism (eg, ribosome, spliceosome), as evident from enriched KEGG pathway analysis of differential mammary tumor gene expression common to both paraben treatments (MP, P < 0.001; PP, P < 0.01). Indeed, mammary tumors from PP-exposed mice had an increased retention of introns (P < 0.05). Our data suggest that parabens cause substantial mammary cancer metastasis in mice as a function of their increasing alkyl chain length and highlight the emerging role of aberrant spliceosome activity in breast cancer metastasis.

The Interplay between the Cellular Response to DNA Double-Strand Breaks and Estrogen

Cancer development is often connected to impaired DNA repair and DNA damage signaling pathways. The presence of DNA damage in cells activates DNA damage response, which is a complex cellular signaling network that includes DNA repair, activation of the cell cycle checkpoints, cellular senescence, and apoptosis. DNA double-strand breaks (DSBs) are toxic lesions that are mainly repaired by the non-homologous end joining and homologous recombination repair (HRR) pathways. Estrogen-dependent cancers, like breast and ovarian cancers, are frequently associated with mutations in genes that play a role in HRR. The female sex hormone estrogen binds and activates the estrogen receptors (ERs), ERα, ERβ and G-protein-coupled ER 1 (GPER1). ERα drives proliferation, while ERβ inhibits cell growth. Estrogen regulates the transcription, stability and activity of numerus DDR factors and DDR factors in turn modulate ERα expression, stability and transcriptional activity. Additionally, estrogen stimulates DSB formation in cells as part of its metabolism and proliferative effect. In this review, we will present an overview on the crosstalk between estrogen and the cellular response to DSBs. We will discuss how estrogen regulates DSB signaling and repair, and how DDR factors modulate the expression, stability and activity of estrogen. We will also discuss how the regulation of HRR genes by estrogen promotes the development of estrogen-dependent cancers.

Copper-based metal-organic framework impedes triple-negative breast cancer metastasis via local estrogen deprivation and platelets blockade

Metastasis is one of the main causes of failure in the treatment of triple-negative breast cancer (TNBC). Abnormally estrogen level and activated platelets are the key driving forces for TNBC metastasis. Herein, an "ion/gas" bioactive nanogenerator (termed as IGBN), comprising a copper-based MOF and loaded cisplatin-arginine (Pt-Arg) prodrug is developed for metastasis-promoting tumor microenvironment reprogramming and TNBC therapy. The copper-based MOF not only serves as a drug carrier, but also specifically produces Cu2+ in tumors, which catalytic oxidizing estrogen to reduce estrogen levels in situ. Meanwhile, the rationally designed Pt-Arg prodrug reduced into cisplatin to significantly promote the generation of H2O2 in the tumor, then permitting self-augmented cascade NO gas generation by oxidizing Arg through a H2O2 self-supplied way, thus blocking platelet activation in tumor. We clarified that IGBN inhibited TNBC metastasis through local estrogen deprivation and platelets blockade, affording 88.4% inhibition of pulmonary metastasis in a 4T1 mammary adenocarcinoma model. Notably, the locally copper ion interference, NO gas therapy and cisplatin chemotherapy together resulted in an enhanced therapeutic efficacy in primary tumor ablation without significant toxicity. This "ion/gas" bioactive nanogenerator offers a robust and safe strategy for TNBC therapy.

The Pathological Mechanisms of Estrogen-Induced Cholestasis: Current Perspectives

Estrogens are steroid hormones with a wide range of biological activities. The excess of estrogens can lead to decreased bile flow, toxic bile acid (BA) accumulation, subsequently causing intrahepatic cholestasis. Estrogen-induced cholestasis (EIC) may have increased incidence during pregnancy, and within women taking oral contraception and postmenopausal hormone replacement therapy, and result in liver injury, preterm birth, meconium-stained amniotic fluid, and intrauterine fetal death in pregnant women. The main pathogenic mechanisms of EIC may include deregulation of BA synthetic or metabolic enzymes, and BA transporters. In addition, impaired cell membrane fluidity, inflammatory responses and change of hepatocyte tight junctions are also involved in the pathogenesis of EIC. In this article, we review the role of estrogens in intrahepatic cholestasis, and outlined the mechanisms of EIC, providing a greater understanding of this disease.

Nitrogen and 17β-Estradiol level regulate Thermosynechococcus sp. CL-1 carbon dioxide fixation, monosaccharide production, and estrogen degradation

Thermosynechococcus sp. CL-1 (TCL-1), a thermophilic cyanobacterium from a hot spring in Taiwan, has been known of its efficiency in CO₂ fixation, byproducts production (pigments, macromolecules). This study observed the performance of TCL-1 in CO₂ fixation, estrogen degradation, and monosaccharide production under various levels of Dissolved Inorganic Nitrogen (DIN) and 17β-estradiol (E2) as nitrogen supply and estrogen addition. Under nitrogen starvation, TCL-1 performed similar results on CO₂ fixation rate and biomass production but enhanced the monosaccharide production compared to the cases of high nitrogen supply. The highest CO₂ fixation rate and glucose productivity reached to 151.8 ± 6.6 and 38.1 ± 0.9 mg/L/h, under DIN level of 0.58 mM and 0.5 mg/L E2. Adding E2 in the system did not inhibit the performance of TCL-1. During the cultivation, TCL-1 converted E2 into E1 and the biodegradation was the main path for estrogen degradation. Total E2 degradation reached to 69.4 ± 2.0%.

Estrogen inhibits the growth of colon cancer in mice through reversing extracellular vesicle-mediated immunosuppressive tumor microenvironment

Postmenopausal women taking estrogen supplements are at a lower risk of advanced colorectal cancer, but the underlying mechanism remains unclear. Thus, this study examined the role of estrogen in colorectal cancer. Estrogen receptor expression levels in in situ colorectal cancer tissue from female patients increased significantly, indicating their estrogen sensitivity. Compared with the sham-operated group, the growth of MC38 tumors was enhanced in ovariectomized mice, which was reversed in ovariectomized mice with E2 supplementation. The PD-L1⁺ M2-like macrophage, regulatory T (Treg) cell, and myeloid-derived suppressor cell (MDSC) populations significantly increased, and the population of cytotoxic CD8⁺ T cells declined in MC38 tumors in ovariectomized mice, which were all reversed in ovariectomized mice with E2 supplementation. MC38 cell-derived extracellular vesicles (MC38-EVs), but not EVs derived from MC38 cells treated with E2 (E2-MC38-EVs), were involved in the establishment of immunosuppressive tumor microenvironment. E2-MC38-EVs contained lower TGF-β1 levels and were less capable of inducing Treg cells than MC38-EVs in vitro. Overall, these results show that estrogen treatment prevents MC38 tumor growth via regulating the tumor immune microenvironment through MC38-EVs.

Development and validation of a high performance liquid chromatography/diode array detection method for estrogen determination: Application to residual analysis in meat products

In this work, an HPLC-DAD method was developed for the residual analysis of some estrogens such as estrone (E1), 17-β estradiol (E2), estriol (E3), natural estrogens, and 17-α ethinylestradiol (E4), an exoestrogen, in meat samples of different categories (chicken, n = 155, beef, n = 124, sheep, n = 122, and camels, n = 40), collected from the Saudi Market. Although banned, the use of E4 as a growth promoter in the black market is still encountered. Symmetry C18 column (3.5 µm, 4.6 mm × 150 mm) was used with a mobile phase consisting of 50% aqueous acetonitrile. Protein precipitation with acetonitrile was used for the sample preparation. The method was fully validated, as per the ICH guidelines, in the concentration ranges of 0.35–125 µg/g (E1, E2), 0.188–125 µg/g (E3), and 0.188–450 µg/g (E4). The method allowed the trace analysis of estrogens with LOD values of 0.094 (E3, E4) and 0.126 µg/g (E1, E2), and LOQ values of 0.188 (E3, E4) and 0.350 µg/g (E1, E2). The analyzed samples contained different levels of estrogens. Within the same category, processed products contained the highest levels of E4, while the internal organs contained the least estrogen content. Finally, the estimated daily intake, µg/kg bw/day, of estrogens through the consumption of meat-based food products was calculated.

Retinoic acid signaling in ovarian folliculogenesis and steroidogenesis

Retinoids are essential for reproduction. Most research has focused on the role of retinoic acid signaling in the regulation of meiosis during early fetal germ cell development. However, less attention has been paid to the possible effects of retinoic acid signaling in adult female gonads. Retinoic acid, its receptors, and the key enzymes required for retinoic acid synthesis are expressed in the ovaries and they are involved in the regulation of folliculogenesis and steroidogenesis. Exposure to compounds that can interfere with normal retinoic acid signaling is associated with adverse ovarian outcomes, including altered steroidogenesis and reduction in indicators of ovarian reserve in women and laboratory animal models. These observations call for more attention to retinoids as regulators of adult ovarian physiology and as possible targets of endocrine disruption by environmental chemicals. In this review, we summarize the current knowledge of retinoids in folliculogenesis and steroidogenesis in post-pubertal mammalian ovaries.