p53 rapidly restructures 3D chromatin organization to trigger a transcriptional response.

Activation of the p53 tumor suppressor triggers a transcriptional program to control cellular response to stress. However, the molecular mechanisms by which p53 controls gene transcription are not completely understood. Here, we uncover the critical role of spatio-temporal genome architecture in this process.

NR5A2/LRH-1 regulates the PTGS2-PGE-PTGER1 pathway contributing to pancreatic islet survival and function.

LRH-1/NR5A2 is implicated in islet morphogenesis postnatally, and its activation using the agonist BL001 protects islets against apoptosis, reverting hyperglycemia in mouse models of Type 1 Diabetes Mellitus. Islet transcriptome profiling revealed that the expression of PTGS2/COX2 is increased by BL001. Herein, we sought to define the role of LRH-1 in postnatal islet morphogenesis and chart the BL001 mode of action conferring beta cell protection.

Exploring the Implication of DDX3X in DENV Infection: Discovery of the First-in-Class DDX3X Fluorescent Inhibitor.

In the absence of effective drugs or vaccines for the treatment of the five Dengue Virus serotypes, the search for novel antiviral drugs is of primary importance for the scientific community. In this context, drug repurposing represents the most used strategy; however, the study of host targets is now attracting attention since it allows identification of broad-spectrum drugs endowed with high genetic barrier. In the last ten years our research group identified several small molecules DDX3X inhibitors and proved their efficacy against different viruses including novel emerging ones.

Effects of oestrogen on microRNA expression in hormone-responsive breast cancer cells.

Oestrogen receptor alpha (ERα) is a ligand-dependent transcription factor that mediates oestrogen effects in hormone-responsive cells. Following oestrogenic activation, ERα directly regulates the transcription of target genes via DNA binding. MicroRNAs (miRNAs) represent a class of small noncoding RNAs that function as negative regulators of protein-coding gene expression.

Direct regulation of microRNA biogenesis and expression by estrogen receptor beta in hormone-responsive breast cancer.

Estrogen effects on mammary epithelial and breast cancer (BC) cells are mediated by the nuclear receptors ERα and ERβ, transcription factors that display functional antagonism with each other, with ERβ acting as oncosuppressor and interfering with the effects of ERα on cell proliferation, tumor promotion and progression. Indeed, hormone-responsive, ERα+ BC cells often lack ERβ, which when present associates with a less aggressive clinical phenotype of the disease. Recent evidences point to a significant role of microRNAs (miRNAs) in BC, where specific miRNA expression profiles associate with distinct clinical and biological phenotypes of the lesion.

Identification of proteins associated with ligand-activated estrogen receptor α in human breast cancer cell nuclei by tandem affinity purification and nano LC-MS/MS.

Estrogen receptor α (ER-α) is a key mediator of estrogen actions in breast cancer (BC) cells. Understanding the effects of ligand-activated ER-α in target cells requires identification of the molecular partners acting in concert with this nuclear receptor to transduce the hormonal signal. We applied tandem affinity purification (TAP), glycerol gradient centrifugation and MS analysis to isolate and identify proteins interacting with ligand-activated ER-α in MCF-7 cell nuclei.

A large set of estrogen receptor β-interacting proteins identified by tandem affinity purification in hormone-responsive human breast cancer cell nuclei.

Estrogen receptors α (ER-α) and β (ER-β) play distinct biological roles in onset and progression of hormone-responsive breast cancer, with ER-β exerting a modulatory activity on ER-α-mediated estrogen signaling and stimulation of cell proliferation by mechanisms still not fully understood. We stably expressed human ER-β fused to a tandem affinity purification-tag in estrogen-responsive MCF-7 cells and applied tandem affinity purification and nanoLC-MS/MS to identify the ER-β interactome of this cell type. Functional annotation by bioinformatics analyses of the 303 proteins that co-purify with ER-β from nuclear extracts identify several new molecular partners of this receptor subtype that represents nodal points of a large protein network controlling multiple processes and functions in breast cancer cells.

Comparative analysis of nuclear estrogen receptor alpha and beta interactomes in breast cancer cells.

Estrogen Receptor alpha and beta (ER-α and -β) are members of the nuclear receptor family of transcriptional regulators with distinct roles in mediating estrogen dependent breast cancer cell growth and differentiation. Following activation by the hormone, these proteins undergo conformation changes and accumulate in the nucleus, where they bind to chromatin at regulatory sites as homo- and/or heterodimers and assemble in large multiprotein complexes. Although the two ERs share a conserved structure, they exert specific and distinct functional roles in normal and transformed mammary epithelial cells and other cell types.

Molecular analysis of the apoptotic effects of BPA in acute myeloid leukemia cells.

Background: BPA (bisphenol A or 2,2-bis(4-hydroxy-phenol)propane) is present in the manufacture of polycarbonate plastic and epoxy resins, which can be used in impact-resistant safety equipment and baby bottles, as protective coatings inside metal food containers, and as composites and sealants in dentistry. Recently, attention has focused on the estrogen-like and carcinogenic adverse effects of BPA. Thus, it is necessary to investigate the cytotoxicity and apoptosis-inducing activity of this compound.

Quantitative expression profiling of highly degraded RNA from formalin-fixed, paraffin-embedded breast tumor biopsies by oligonucleotide microarrays.

Microarray-based gene expression profiling is well suited for parallel quantitative analysis of large numbers of RNAs, but its application to cancer biopsies, particularly formalin-fixed, paraffin-embedded (FFPE) archived tissues, is limited by the poor quality of the RNA recovered. This represents a serious drawback, as FFPE tumor tissue banks are available with clinical and prognostic annotations, which could be exploited for molecular profiling studies, provided that reliable analytical technologies are found. We applied and evaluated here a microarray-based cDNA-mediated annealing, selection, extension and ligation (DASL) assay for analysis of 502 mRNAs in highly degraded total RNA extracted from cultured cells or FFPE breast cancer (MT) biopsies.

Differentiation of myeloid cell lines correlates with a selective expression of RIZ protein.

Background: The retinoblastoma-interacting zinc-finger gene RIZ is expressed in two forms (RIZ1 and RIZ2) that differ for the presence near the N-terminus of RIZ1 of a conserved domain, defined PR (PRDI-BF1-RIZ homology), homologous to a similar domain present in other proteins recognized as tumor suppressor gene products. The RIZ1 form is usually absent or expressed at low levels in tumor cells, whereas RIZ2 is frequently expressed. We investigated a possible involvement of RIZ1 in differentiation control using a myeloid cell maturation model that is easily modulated by retinoids and other agents.

Serum anti-p53 antibodies in lung cancer: comparison with established tumor markers.

As reported earlier, p53 antibodies are detected in the sera of patients with different types of cancer, including lung cancer. In contrast, in the serum of healthy subjects the presence of anti-p53 antibodies is extremely rare. We collected the venous blood samples of 109 patients affected with lung cancer (LC): 57 patients (46 M, 11 F) with non-small-cell carcinoma (NSCLC), 52 others (40 M, 12 F) with small-cell carcinoma (SCLC).

Estradiol induces functional inactivation of p53 by intracellular redistribution.

Estrogen treatment of MCF-7 cells grown in serum-free medium induced a modification of the intracellular distribution of p53 protein. Western blot analysis and immunofluorescence staining showed that p53 was localized in the nucleus of untreated cell and that after 48 h of hormone treatment, it was mostly localized in the cytoplasm. This effect was blocked by the antiestrogen ICI182,780.

Tyrosine kinase/p21ras/MAP-kinase pathway activation by estradiol-receptor complex in MCF-7 cells.

The mechanism by which estradiol acts on cell multiplication is still unclear. Under conditions of estradiol-dependent growth, estradiol treatment of human mammary cancer MCF-7 cells triggers rapid and transient activation of the mitogen-activated (MAP) kinases, erk-1 and erk-2, increases the active form of p21ras, tyrosine phosphorylation of Shc and p190 protein and induces association of p190 to p21ras-GAP. Both Shc and p190 are substrates of activated src and once phosphorylated, they interact with other proteins and upregulate p21ras.

In vitro phosphorylation and hormone binding activation of the synthetic wild type human estradiol receptor.

A tyrosine kinase purified from calf uterus activates the hormone binding of endogenous estradiol receptor (ER) predephosphorylated and preinactivated by a nuclear phosphotyrosine phosphatase. The kinase also activates and phosphorylates the human estradiol receptor HEO synthesized in vitro, which differs from the wild type receptor HEGO because a glycine is replaced by a valine at position 400. Moreover, the kinase activates and phosphorylates a deletion mutant of HEO which consists almost exclusively of the hormone binding domain.

In vitro interaction of estradiol receptor with Ca2+-calmodulin.

Estradiol receptor (ER) activity requires interaction with hormone and specific DNA sequence. We now report that this receptor also interacts with calmodulin (CaM), the major intracellular mediator of Ca2+ action in eucaryotic cells. This interaction has been observed using both CaM-Sepharose and [125I]CaM.

Oestradiol stimulates tyrosine phosphorylation and hormone binding activity of its own receptor in a cell-free system.

Recent experiments have shown that calf uterus oestrogen receptor exists in a tyrosine-phosphorylated hormone binding form and in non-phosphorylated, non-hormone binding form. We report here that physiological concentrations of oestradiol in complex with the receptor stimulate the calf uterus receptor kinase that converts the non-hormone binding receptor into hormone binding receptor through phosphorylation of the receptor on tyrosine. The activity of this enzyme has been followed by reactivation of hormone binding sites and phosphorylation on tyrosine of calf uterus phosphatase-inactivated receptor.

Phosphorylation on tyrosine of oestradiol-17 beta receptor in uterus and interaction of oestradiol-17 beta and glucocorticoid receptors with antiphosphotyrosine antibodies.

In whole rat uterus incubated in the presence of [32P]orthophosphate the oestradiol receptor is [32P]phosphorylated on tyrosine. This finding follows our previous observation that in vitro this receptor can be phosphorylated on tyrosine by a uterus kinase that endows the receptor with oestradiol-binding activity. The calf uterus oestradiol receptor interacts with high affinity with 2G8 and 1G2 antiphosphotyrosine antibodies coupled to Sepharose (Kd values of 0.

Estradiol and progesterone receptors in malignant gastrointestinal tumors.

Estradiol and progesterone receptors were assayed in tumors from 79 patients with primary colorectal and 56 patients with stomach adenocarcinomas. Eighteen of 79 colorectal cancers contained estradiol receptor, while 34 specimens were positive for progesterone receptor. In stomach cancer, the positive samples were 8 for estradiol and 14 for progesterone receptors.

Estrogen and progesterone binding proteins in human colorectal cancer. A preliminary characterization of estradiol receptor.

Estradiol receptor (ER) and progesterone receptor (PgR) were assayed in tumors from 20 patients with primary colorectal cancer. Ten of 20 tumors contained high affinity sites for 17 beta-estradiol and progesterone. The highest concentration of ER was 56 fmol/mg of protein.