Crucial role of phospholamban phosphorylation and S-nitrosylation in the negative lusitropism induced by 17β-estradiol in the male rat heart.

Background/Aims: 17β-estradiol (17βE2) plays an important cardiovascular role by activating estrogen receptors (ER) α and ERβ. Previous studies demonstrated that the novel estrogen G protein-coupled receptor (GPR30/GPER) mediates estrogen action in different tissues. We have recently shown in the rat heart that 17βE2 elicits negative inotropism through ERα, ERβ and GPR30, by triggering activation of ERK1/2, phosphatidylinositol 3-kinase (PI3K), protein kinase A (PKA) and endothelial Nitric Oxide synthase (eNOS) signaling. Methods: In the present study, using the isolated and Langendorff-perfused rat heart as a model system we analyzed: i) whether and to which extent 17βE2 modifies mammalian ventricular myocardial relaxation (lusitropism); ii) the type of ERs and the signaling pathways involved in this effect. Results: We found that 17βE2 negatively modulated the ventricular lusitropic performance. This effect, which partially involved the vascular endothelium, recruited ERβ and occurred via PI3K, eNOS-NO-cGMP-protein kinase G (PKG) transduction cascade. Of note, 17βE2-mediated negative lusitropism associated with a modification of phospholamban (PLN) phosphorylation and S-nitrosylation (SNO) both in isolated Langendorff rat heart and in isolated cardiomyocytes. Conclusion: Taken together, our results allow including 17βE2 to the family of substances that control ventricular relaxation. This is of relevance in relation not only to the normal endocrine control of cardiac function, but also to physio-pathologic conditions characterized by an altered ventricular diastolic performance

A mitochondrial based oncology platform for targeting cancer stem cells (CSCs) : MITO-ONC-RX

Here, we wish to propose a new systematic approach to cancer therapy, based on the targeting of mitochondrial metabolism, especially in cancer stem cells (CSCs). In the future, we envision that anti-mitochondrial therapy would ultimately be practiced as an add-on to more conventional therapy, largely for the prevention of tumor recurrence and cancer metastasis. This mitochondrial based oncology platform would require a panel of FDA-approved therapeutics (e.g. Doxycycline) that can safely be used to inhibit mitochondrial OXPHOS and/or biogenesis in CSCs. In addition, new therapeutics that target mitochondria could also be developed, to optimize their ability to eradicate CSCs. Finally, in this context, mitochondrial-based biomarkers (i.e. “Mito-signatures”) could be utilized as companion diagnostics, to identify high-risk cancer patients at diagnosis, facilitating the early detection of tumor recurrence and the prevention of treatment failure. In summary, we suggest that new clinical trials are warranted to test and possibly implement this emerging treatment strategy, in a variety of human cancer types. This general approach, using FDA-approved antibiotics to target mitochondria, was effective in killing CSCs originating from many different cancer types, including DCIS, breast (ER(+) and ER(-)), prostate, ovarian, lung and pancreatic cancers, as well as melanoma and glioblastoma, among others. Thus, we propose the term MITO-ONC-RX, to describe this anti-mitochondrial platform for targeting CSCs. The use of re-purposed FDA-approved drugs will undoubtedly help to accelerate the clinical evaluation of this approach, as these drugs can move directly into Phase II clinical trials, saving considerable amounts of time (10–15 y) and billions in financial resources

Activation of the S100A7/RAGE Pathway by IGF-1 Contributes to Angiogenesis in Breast Cancer

Background: Breast cancer (BC) mortality is increased among obese and diabetic patients. Both obesity and diabetes are associated with dysregulation of both the IGF-1R and the RAGE (Receptor for Advanced Glycation End Products) pathways, which contribute to complications of these disorders. The alarmin S100A7, signaling through the receptor RAGE, prompts angiogenesis, inflammation, and BC progression. Methods: We performed bioinformatic analysis of BC gene expression datasets from published studies. We then used Estrogen Receptor (ER)-positive BC cells, CRISPR-mediated IGF-1R KO BC cells, and isogenic S100A7-transduced BC cells to investigate the role of IGF-1/IGF-1R in the regulation of S100A7 expression and tumor angiogenesis. To this aim, we also used gene silencing and pharmacological inhibitors, and we performed gene expression and promoter studies, western blotting analysis, ChIP and ELISA assays, endothelial cell proliferation and tube formation assay. Results: S100A7 expression correlates with worse prognostic outcomes in human BCs. In BC cells, the IGF-1/IGF-1R signaling engages STAT3 activation and its recruitment to the S100A7 promoter toward S100A7 increase. In human vascular endothelial cells, S100A7 activates RAGE signaling and prompts angiogenic effects. Conclusions: In ER-positive BCs the IGF-1 dependent activation of the S100A7/RAGE signaling in adjacent endothelial cells may serve as a previously unidentified angiocrine effector. Targeting S100A7 may pave the way for a better control of BC, particularly in conditions of unopposed activation of the IGF-1/IGF-1R axis

Novel Mechanisms of Tumor Promotion by the Insulin Receptor Isoform A in Triple-Negative Breast Cancer Cells

The insulin receptor isoform A (IR-A) plays an increasingly recognized role in fetal growth and tumor biology in response to circulating insulin and/or locally produced IGF2. This role seems not to be shared by the IR isoform B (IR-B). We aimed to dissect the specific impact of IR isoforms in modulating insulin signaling in triple negative breast cancer (TNBC) cells. We generated murine 4T1 TNBC cells deleted from the endogenous insulin receptor (INSR) gene and expressing comparable levels of either human IR-A or IR-B. We then measured IR isoform-specific in vitro and in vivo biological effects and transcriptome in response to insulin. Overall, the IR-A was more potent than the IR-B in mediating cell migration, invasion, and in vivo tumor growth. Transcriptome analysis showed that approximately 89% of insulin-stimulated transcripts depended solely on the expression of the specific isoform. Notably, in cells overexpressing IR-A, insulin strongly induced genes involved in tumor progression and immune evasion including chemokines and genes related to innate immunity. Conversely, in IR-B overexpressing cells, insulin predominantly induced the expression of genes primarily involved in the regulation of metabolic pathways and, to a lesser extent, tumor growth and angiogenesis

The Cholesterol Metabolite 25-Hydroxycholesterol Activates Estrogen Receptor α-Mediated Signaling in Cancer Cells and in Cardiomyocytes

The hydroxylated derivatives of cholesterol, such as the oxysterols, play important roles in lipid metabolism. In particular, 25-hydroxycholesterol (25 HC) has been implicated in a variety of metabolic events including cholesterol homeostasis and atherosclerosis. 25 HC is detectable in human plasma after ingestion of a meal rich in oxysterols and following a dietary cholesterol challenge. In addition, the levels of oxysterols, including 25 HC, have been found to be elevated in hypercholesterolemic serum.Here, we demonstrate that the estrogen receptor (ER) α mediates gene expression changes and growth responses induced by 25 HC in breast and ovarian cancer cells. Moreover, 25 HC exhibits the ERα-dependent ability like 17 β-estradiol (E2) to inhibit the up-regulation of HIF-1α and connective tissue growth factor by hypoxic conditions in cardiomyocytes and rat heart preparations and to prevent the hypoxia-induced apoptosis.The estrogen action exerted by 25 HC may be considered as an additional factor involved in the progression of breast and ovarian tumors. Moreover, the estrogen-like activity of 25 HC elicited in the cardiovascular system may play a role against hypoxic environments

Ruolo di GPER sulla funzione cardiovascolare in condizioni di ipertensione: caratterizzazione fisiologica del recettore in Ratti Spontaneamente ipertesi (SHR)

Dottorato di ricerca in Biologia animle, Ciclo XXVI, a.a. 2012-2013Estrogens promote beneficial effects in the cardiovascular system mainly through the estrogen receptor (ER)α and ERβ, which act as ligand-gated transcription factors. Recently, the G protein-coupled estrogen receptor (GPER) has been implicated in the estrogenic signaling in diverse tissues, including the cardiovascular system. In this study, we demonstrate that left ventricles of male Spontaneously Hypertensive Rats (SHR) express higher levels of GPER compared to normotensive Wistar Kyoto (WKY) rats. In addition, we show that the selective GPER agonist G-1 induces negative inotropic and lusitropic effects to a higher extent in isolated and Langendorff perfused hearts of male SHR compared to WKY rats. These cardiotropic effects elicited by G-1 involved the GPER/eNOS transduction signaling, as determined by using the GPER antagonist G-15 and the eNOS inhibitor L-NIO. Similarly, the G-1 induced activation of ERK1/2, AKT, GSK3β, c-Jun and eNOS was abrogated by G-15, while L-NIO prevented only the eNOS phosphorylation. In hypoxic Langendorff perfused WKY rat heart preparations, we also found an increased expression of GPER along with that of the hypoxic mediator HIF-1α and the fibrotic marker CTGF. Interestingly, G-15 and L-NIO prevented the ability of G-1 to down-regulate the expression of both HIF- 1α and CTGF, which were found expressed to a higher extent in SHR compared to WKY rat hearts. Collectively, the present study provides novel data into the potential role played by GPER in hypertensive disease on the basis of its involvement in myocardial inotropism and lusitropism as well as the expression of the apoptotic HIF-1α and fibrotic CTGF factors. Hence, GPER may be considered as a useful target in the treatment of some cardiac dysfunctions associated with stressful conditions like the essential hypertension.Università della Calabri