Lysine 268 adjacent to transmembrane helix 5 of hamster P-glycoprotein is the major photobinding site of iodomycin in CHO B30 cells.

P-glycoprotein (Pgp) detoxifies cells by exporting hundreds of chemically dissimilar hydrophobic and amphipathic compounds and is implicated in multidrug resistance (MDR) in the treatment of cancers. Photoaffinity labeling of plasma membrane vesicles of MDR CHO B30 cells with the anthracycline [ I]-iodomycin, subsequent sequential cleavage with BNPS-skatol and endoproteinase Lys-C, and the Edman sequencing of the purified photoaffinity-labeled peptide identified the lysine residue at position 268 in the hamster Pgp primary sequence as the major photobinding site of iodomycin in CHO B30 cells. Lysine 268 is located adjacent to the cytosolic terminus of transmembrane 5.

Synthesis and investigation of the anticancer effects of estrone-16-oxime ethers in vitro.

An expanding body of evidence indicates the possible role of estrane derivatives as useful anticancer agents. The aim of this study was to describe the cytotoxic effects of 63 newly synthetized estrone-16-oxime ethers on human cancer cell lines (cervix carcinoma HeLa, breast carcinoma MCF7 and skin epidermoid carcinoma A431), studied by means of the MTT assay. Four of the most promising compounds were selected for participation in additional experiments in order to characterize the mechanism of action, including cell cycle analysis, morphological study and the 5-bromo-2'-deoxyuridine incorporation assay.

Novel estrogen-related genes and potential biomarkers of ovarian endometriosis identified by differential expression analysis.

In the search for novel biomarkers of endometriosis, we selected 152 genes from the GeneLogic database based on results of genome-wide expression analysis of ovarian endometriosis, plus 20 genes related to estrogen metabolism and action. We then performed low-density array analysis of these 172 genes on 11 ovarian endometriosis samples and 9 control endometrium samples. Principal component analysis of the gene expression levels showed clear separation between the endometriosis and control groups.

Species used for drug testing reveal different inhibition susceptibility for 17beta-hydroxysteroid dehydrogenase type 1.

Steroid-related cancers can be treated by inhibitors of steroid metabolism. In searching for new inhibitors of human 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD 1) for the treatment of breast cancer or endometriosis, novel substances based on 15-substituted estrone were validated. We checked the specificity for different 17beta-HSD types and species.

Ligand-based NMR spectra demonstrate an additional phytoestrogen binding site for 17beta-hydroxysteroid dehydrogenase type 1.

The enzyme 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) has become an important drug target for breast cancer because it catalyzes the interconversion of estrone to the biologically more potent estradiol which also plays a crucial role in the etiology of breast cancer. Patients with an increased expression of the 17beta-HSD1 gene have a significantly worse outcome than patients without. Inhibitors for 17beta-HSD1 are therefore included in therapy development.

In vivo mouse model for analysis of hydroxysteroid (17beta) dehydrogenase 1 inhibitors.

Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) catalyzes the reaction between the low active 17-ketosteroids and the highly active 17beta-hydroxysteroids. In the present study, we have generated transgenic (TG) mice expressing human (h) HSD17B1 under mouse mammary tumor virus (MMTV) promoter (MMTV-hHSD17B1TG mice). The MMTV-hHSD17B1TG mice were used to characterize HSD17B1 enzyme activity and properties of HSD17B1 inhibitor in vivo.

Estrone C15 derivatives--a new class of 17beta-hydroxysteroid dehydrogenase type 1 inhibitors.

Lowering local estradiol concentration by inhibition of the estradiol-synthesizing enzyme 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) has been proposed as a promising new therapeutic option to treat estrogen-dependent diseases like endometriosis and breast cancer. Based on a molecular modelling approach we designed and synthesized novel C15-substituted estrone derivatives. Subsequent biological evaluation revealed that potent inhibitors of human 17beta-HSD1 can be identified in this compound class.

Structure-activity study in the class of 6-(3'-hydroxyphenyl)naphthalenes leading to an optimization of a pharmacophore model for 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) inhibitors.

17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyzes the transformation of estrone (E1) into the most potent estrogen, estradiol (E2), which stimulates cell proliferation and decreases apoptosis. 17beta-HSD1 is often strongly overexpressed in estrogen-dependent diseases (like breast cancer and endometriosis). Thus, this over expressed enzyme is a promising novel target for the development of selective inhibitors, which could be used as drugs for the treatment of these diseases.

Disturbed estrogen and progesterone action in ovarian endometriosis.

Endometriosis is a very common disease in pre-menopausal women, where defective metabolism of steroid hormones plays an important role in its development and promotion. In the present study, we have examined the expression of 11 estrogen and progesterone metabolizing enzymes and their corresponding receptors in samples of ovarian endometriomas and control endometrium. Expression analysis revealed significant up-regulation of enzymes involved in estradiol formation (aromatase, sulfatase and all reductive 17beta-hydroxysteroid dehydrogenases) and in progesterone inactivation (AKR1C1 and AKR1C3).

Substituted 6-phenyl-2-naphthols. Potent and selective nonsteroidal inhibitors of 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1): design, synthesis, biological evaluation, and pharmacokinetics.

17beta-Estradiol (E2) is implicated in the genesis and the development of estrogen-dependent diseases. Its concentration is mainly regulated by 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1), which catalyzes the reduction of the weak estrogen estrone (E1) to the highly potent E2. This enzyme is thus an important target for the treatment of hormone-dependent diseases.

Design, synthesis, and biological evaluation of (hydroxyphenyl)naphthalene and -quinoline derivatives: potent and selective nonsteroidal inhibitors of 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) for the treatment of estrogen-dependent diseases.

Human 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyzes the reduction of the weak estrogen estrone (E1) to the highly potent estradiol (E2). This reaction takes place in the target cell where the estrogenic effect is exerted via the estrogen receptor (ER). Estrogens, especially E2, are known to stimulate the proliferation of hormone-dependent diseases.

Expression analysis of the genes involved in estradiol and progesterone action in human ovarian endometriosis.

Endometriosis is defined as the presence of endometrial glands and stroma within extrauterine sites, and it is well known that endometriosis is an estrogen-dependent disease. The defective formation and metabolism of steroid hormones is responsible for the promotion and development of endometriosis. In the present study we examined the mRNA levels of six enzymes that are involved in the metabolism of estrogen and progesterone--aromatase, 17beta-hydroxysteroid dehydrogenase (17beta-HSD) types 1, 2 and 7, sulfatase and sulfotransferase--and of the steroid receptors--estrogen receptors alpha and beta (ERalpha, ERbeta) and progesterone receptors A and B (PRAB)--implicated in human ovarian endometriosis.

Expression and regulation of estrogen-converting enzymes in ectopic human endometrial tissue.

Objective: To investigate the regulation of estrogen-converting enzymes in human ectopic endometrial tissue.

Design: Animal study.

Setting: Academic medical center.

Purification and characterisation of a jacalin-related, coleoptile specific lectin from Hordeum vulgare.

A plant lectin was isolated from barley (Hordeum vulgare) coleoptiles using acidic extraction and different chromatographic methods. Sequencing of more than 50% of the protein sequence by Edman degradation confirmed a full-length cDNA clone. The subsequently identified open reading frame encodes for a 15 kDa protein which could be found in the soluble fraction of barley coleoptiles.

Human hydroxysteroid (17-beta) dehydrogenase 1 expression enhances estrogen sensitivity of MCF-7 breast cancer cell xenografts.

Hydroxysteroid (17-beta) dehydrogenase 1 (HSD17B1) catalyzes the conversion between estrone (E1) and estradiol (E2). The reaction is reversible in vitro, but the data in cultured cells suggest that E2 production is the predominant reaction in physiological conditions. However, the hypothesis has not been verified in vivo.

New inhibitors of 17beta-hydroxysteroid dehydrogenase type 1.

The estradiol-synthesizing enzyme 17beta-hydroxysteroid dehydrogenase type 1 (17betaHSD1) is mainly responsible for the conversion of estrone (E1) to the potent estrogen estradiol (E2). It is a key player to control tissue levels of E2 and is therefore an attractive target in estradiol-dependent diseases like breast cancer or endometriosis. We selected a unique non-steroidal pyrimidinone core to start a lead optimization program.

Caspase-dependent regulation and subcellular redistribution of the transcriptional modulator YY1 during apoptosis.

The transcriptional regulator Yin Yang 1 (YY1) controls many aspects of cell behavior and is essential for development. We analyzed the fate of YY1 during apoptosis and studied the functional consequences. We observed that this factor is rapidly translocated into the cell nucleus in response to various apoptotic stimuli, including activation of Fas, stimulation by tumor necrosis factor, and staurosporine and etoposide treatment.

Dydrogesterone (Duphaston) and its 20-dihydro-derivative as selective estrogen enzyme modulators in human breast cancer cell lines. Effect on sulfatase and on 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity.

Estradiol (E2) is one of the main factors which control the growth and evolution of breast cancer. Consequently, to block the formation of E2 inside cancer cells has been an important target in recent years. Breast cancer cells possess all the enzymatic systems (e.

Phosphatidylcholine metabolism of rat trachea in relation to lung parenchyma and surfactant.

Pulmonary surfactant prevents alveolar collapse and contributes to airway patency by reducing surface tension. Although alveolar surfactant, consisting mainly of phospholipids (PL) together with neutral lipids and surfactant-specific proteins, originates from type II pneumocytes, the contribution of airway epithelia to the PL fraction of conductive airway surfactant is still debated. We, therefore, analyzed the composition, synthesis, and release of phosphatidylcholine (PC) molecular species as the main surfactant PL of the rat trachea compared with the lung.

Occurrence of estrogen receptor alpha in bovine placentomes throughout mid and late gestation and at parturition.

The bovine placenta produces estrogens from the first trimester until the end of its life span. However, with the exception of the immediate prepartal and intrapartal phases, in which an involvement of placental estrogens has been suggested for the preparation of parturition, their function has not been elucidated yet. To test for a role of placental estrogens as local factors regulating placental growth and differentiation, placentomes from cows that were pregnant for 150, 220, 240, and 270 days, and parturient cows (3 animals per group) were screened immunohistochemically for the expression of estrogen receptor alpha (ERalpha).

Purification and characterization of the thyrotropin-releasing hormone (TRH)-degrading serum enzyme and its identification as a product of liver origin.

Previous biochemical studies have indicated that the membrane-bound thyrotropin-releasing hormone (TRH)-degrading enzyme (TRH-DE) from brain and liver and the serum TRH-DE are derived from the same gene. These studies also suggested that the serum enzyme is of liver origin. The present study was undertaken to verify these hypotheses.