IGFBP-2 expression in MCF-7 cells is regulated by the PI3K/AKT/mTOR pathway through Sp1-induced increase in transcription.

Insulin-like growth factor binding protein 2 (IGFBP-2) has been implicated in the pathophysiology of neoplasia. The PI3K/AKT/mTOR pathway has recently been shown to be a predominant regulator of IGFBP-2 at the protein level in MCF-7 breast cancer cells. However, there are gaps in knowledge with respect to the molecular mechanisms that underlie this regulation. Here, we show that the PI3K/AKT/mTOR pathway regulates IGFBP-2 protein levels by modulating IGFBP-2 mRNA abundance in MCF-7 cells. This change is achieved by regulating transcription through a critical region present in the first 200 bp upstream of the transcription initiation site where Sp1 transcription factor binds and drives transcription. IGF-1 treatment leads to increased nuclear abundance of Sp1 and increased IGFBP-2 mRNA and protein levels. Rapamycin and LY294002 induce a decline in Sp1 nuclear abundance and IGFBP-2 mRNA and protein levels. This work provides a mechanistic explanation for the observed effects of the PI3K/AKT/mTOR pathway on IGFBP-2 levels in MCF-7 cells.

PTEN genomic deletion is associated with p-Akt and AR signalling in poorer outcome, hormone refractory prostate cancer.

PTEN haploinsufficiency is common in hormone-sensitive prostate cancer, though the incidence of genomic deletion and its downstream effects have not been elucidated in clinical samples of hormone refractory prostate cancer (HRPC). Progression to androgen independence is pivotal in prostate cancer and mediated largely by the androgen receptor (AR). Since this process is distinct from metastatic progression, we examined alterations of the PTEN gene in locally advanced recurrent, non-metastatic human HRPC tissues. Retrospective analyses of PTEN deletion status were correlated with activated downstream phospho-Akt (p-Akt) pathway proteins and with the androgen receptor. The prevalence of PTEN genomic deletions in transurethral resection samples of 59 HRPC patients with known clinical outcome was assessed by four-colour FISH analyses. FISH was performed using six BAC clones spanning both flanking PTEN genomic regions and the PTEN gene locus, and a chromosome 10 centromeric probe. PTEN copy number was also evaluated in a subset of cases using single nucleotide polymorphism (SNP) arrays. In addition, the samples were immunostained with antibodies against p-Akt, p-mTOR, p-70S6, and AR. The PTEN gene was deleted in 77% of cases, with 25% showing homozygous deletions, 18% homozygous and hemizygous deletions, and 34% hemizygous deletions only. In a subset of the study group, SNP array analysis confirmed the FISH findings. PTEN genomic deletion was significantly correlated to the expression of downstream p-Akt (p < 0.0001), AR (p = 0.025), and to cancer-specific mortality (p = 0.039). PTEN deletion is common in HRPC, with bi-allelic loss correlating to disease-specific mortality and associated with Akt and AR deregulation.

Fascin regulates prostate cancer cell invasion and is associated with metastasis and biochemical failure in prostate cancer.

PURPOSE: Prostate cancer metastasis to secondary organs is considered an initial event in the development of hormone refractory disease and remains the major cause of death among prostate cancer patients. In this study, we investigated the role of fascin, a cytoskeleton actin-bundling protein involved in the formation of filopodia and cell migration, in prostate cancer progression. EXPERIMENTAL DESIGN: Fascin protein expression was examined by immunohistochemistry in a cohort of 196 patients with localized prostate cancer and across several stages of disease progression, including hormone refractory disease. Cellular changes were also assessed in vitro and in vivo in DU145 prostate cancer cell line using fascin gene silencing. RESULTS: Fascin epithelial expression was significantly up-regulated in localized and hormone refractory prostate cancer compared with benign prostate tissue (P<0.05). Furthermore, high fascin expression was associated with an increased rate of prostate-specific antigen recurrence following radical prostatectomy (P=0.075), signifying more aggressive clinical course, thus supporting a function for fascin in prostate cancer progression. In cellular models, fascin gene silencing using small interfering RNA in the androgen-independent prostate cancer cell line DU145 decreased cell motility and invasiveness while increasing cell adhesive properties. In addition, fascin small interfering RNA-expressing DU145 cells implanted orthotopically in mouse prostate showed significantly decreased growth (P<0.005) and drastically prevented the formation of lymph node metastases (P<0.001) compared with their matched controls. CONCLUSIONS: Our data show a function of fascin in the regulation of prostate cancer progression and emphasize the importance of fascin as a prognostic marker for aggressive disease and as a potential therapeutic target for advanced androgen independent disease.

Identification of deregulated genes by single wall carbon-nanotubes in human normal bronchial epithelial cells.

To identify genes affected by single-walled carbon nanotubes (SWCNTs) in human normal lung cells, we compared the gene expression profiles of untreated human normal bronchial epithelial (HNBE) cells to profiles of HNBE cells treated with SWCNTs. A complementary DNA microarray analysis consisting of 54,675 human genes revealed marked changes in the expression of 14,294 genes, with 7,029 genes being upregulated and 7,265 being downregulated. This comprehensive list of genes included those associated with cell cycle, apoptosis, cell survival, cell adhesion and motility, signal transduction, and transcription regulation. Additional analysis of 19 genes using reverse transcription-polymerase chain reaction confirmed the microarray analysis. More specifically, our study demonstrates to our knowledge for the first time, evidence that 9 of the 19 genes (most of which encode cell apoptotic, signal transduction, and transcription regulator products) are upregulated in the SWCNTs-treated HNBE cells as compared with untreated cells, whereas the remaining 10 of the 19 (involved in cell adhesion and motility, cell proliferation, and cell survival) are downregulated in SWCNTs-treated HNBE cells in comparison with untreated controls. These findings provide a large body of information regarding gene expression profiles associated with SWCNTs exposure in human lung bronchial epithelial cells, and also represent a source to investigate the mechanism of the effect of SWCNTs in human normal lung cells. From the clinical editor: In this study, the gene expression profile of human normal bronchial epithelial cells was compared with single-wall carbon nanotubes-treated cells. A cDNA microarray analysis consisting of 54,675 human genes revealed significant changes in the expression of 14,294 genes, with 7,029 genes being up-regulated and 7,265 being down-regulated. This serves as a first step in clarification of mechanisms of action and to investigate toxicity in this model.

Focal adhesion kinase-related proline-rich tyrosine kinase 2 and focal adhesion kinase are co-overexpressed in early-stage and invasive ErbB-2-positive breast cancer and cooperate for breast cancer cell tumorigenesis and invasiveness.

Early cancer cell migration and invasion of neighboring tissues are mediated by multiple events, including activation of focal adhesion signaling. Key regulators include the focal adhesion kinase (FAK) and FAK-related proline-rich tyrosine kinase 2 (Pyk2), whose distinct functions in cancer progression remain unclear. Here, we compared Pyk2 and FAK expression in breast cancer and their effects on ErbB-2-induced tumorigenesis and the potential therapeutic utility of targeting Pyk2 compared with FAK in preclinical models of breast cancer. Pyk2 is overexpressed in tissues from early and advanced breast cancers and overexpressed with both FAK and epidermal growth factor receptor-2 (ErbB-2) in a subset of breast cancer cases. Down-regulation of Pyk2 in ErbB-2-positive, FAK-proficient, and FAK-deficient cells reduced cell proliferation, which correlated with reduced mitogen-activated protein kinase (MAPK) activity. In contrast, Pyk2 silencing had little impact on cell migration and invasion. In vivo, Pyk2 down-regulation reduced primary tumor growth induced by a metastatic variant of ErbB-2-positive MDA 231 breast cancer cells but had little effect on lung metastases in contrast to FAK down-regulation. Dual reduction of Pyk2 and FAK expression resulted in strong inhibition of both primary tumor growth and lung metastases. Together, these data support the cooperative function of Pyk2 and FAK in breast cancer progression and suggest that dual inhibition of FAK and Pyk2 is an efficient therapeutic approach for targeting invasive breast cancer.

Identification of a novel truncating PALB2 mutation and analysis of its contribution to early-onset breast cancer in French-Canadian women.

BACKGROUND: PALB2 has recently been identified as a breast cancer susceptibility gene. PALB2 mutations are rare causes of hereditary breast cancer but may be important in countries such as Finland where a founder mutation is present. We sought to estimate the contribution of PALB2 mutations to the burden of breast cancer in French Canadians from Quebec. METHODS: We screened all coding exons of PALB2 in a sample of 50 French-Canadian women diagnosed with either early-onset breast cancer or familial breast cancer at a single Montreal hospital. The genetic variants identified in this sample were then studied in 356 additional women with breast cancer diagnosed before age 50 and in 6,448 newborn controls. RESULTS: We identified a single protein-truncating mutation in PALB2 (c.2323 C>T, resulting in Q775X) in 1 of the 50 high-risk women. This variant was present in 2 of 356 breast cancer cases and in none of 6,440 newborn French-Canadian controls (P = 0.003). We also identified two novel new non-synonymous single nucleotide polymorphisms in exon 4 of PALB2 (c.5038 A>G [I76V] and c.5156 G>T [G115V]). G115V was found in 1 of 356 cases and in 15 of 6,442 controls (P = 0.6). The I76V variant was not identified in either the extended case series or the controls. CONCLUSION: We have identified a novel truncating mutation in PALB2. The mutation was found in approximately 0.5% of unselected French-Canadian women with early-onset breast cancer and appears to have a single origin. Although mutations are infrequent, PALB2 can be added to the list of breast cancer susceptibility genes for which founder mutations have been identified in the French-Canadian population.

Systemic distribution of steroid sulfatase and estrogen sulfotransferase in human adult and fetal tissues.

Estrogens play a key role in various target tissues. Enzymes involved in the biosynthesis and metabolism of these sex steroids also regulate estrogenic actions in these tissues. Estrone sulfate (E1S) is a major circulating plasma estrogen that is converted into the biologically active estrogen, estrone (E1), by steroid sulfatase (STS). E1 is also sulfated and reverted into E1S by estrogen sulfotransferase (EST). These two enzymes have recently been shown to play important roles in the in situ estrogen actions of various sex steroid-dependent human tumors. However, the distribution of STS and EST in normal adult and fetal human tissues remains largely unknown. Therefore, in this study, in addition to examining the tissue distribution of both STS and EST mRNA in human adult and fetal tissues using RT followed by quantitative PCR, we studied the activity of these enzymes using (3)H-labeled E1/E1S as substrates in the homogenates of various human adult tissues. We also examined the localization of STS and EST protein in human adult and fetal tissues using immunohistochemistry, and that of EST mRNA in the adult kidney using laser dissection microscopy and PCR. STS mRNA, enzyme activity, and immunoreactivity were either absent or detected at very low levels in all adult and fetal tissues examined in this study. EST mRNA expression, however, was detected in all of the tissues examined, except for adult spleen and pancreas. EST enzyme activities were consistent with those of mRNA expression in the great majority of the tissues examined. Marked EST immunoreactivity was detected in hepatocytes, adrenal gland (adult, zona fasciculate to the reticularis; fetus, fetal zone), and epithelial cells of the gastrointestinal tract, smooth muscle cells of the tunica media in aorta, Leydig cells of the testis, and syncytiotrophoblast of the placenta. Patterns of EST immunolocalization were similar between adult and fetal human tissues, but EST immunoreactivity was detected in the urinary tubules of adult kidney, whereas in the fetal kidney, it was localized in the interstitial cells surrounding the urinary tubules. In the adult kidney, the presence of EST mRNA was also confirmed in the cells of urinary tubules using laser dissection microscopy and RT-PCR. Although the number of human tissues available for examination in this study was limited, our results suggest that between the enzymes involved in estrogen activation or inactivation, EST and not STS is the more widely expressed enzyme in various peripheral tissues in humans. We speculate that EST may play an important role in protecting peripheral tissues from possible excessive estrogenic effects.

Progesterone production and actions in the human central nervous system and neurogenic tumors.

Progesterone has been suggested to be involved in the functions of the nervous system, but it has yet to be examined in humans. Progesterone has also been postulated to be involved in the biological behavior of various human neurogenic tumors via progesterone receptors A and B (PR-A and PR-B). In this study we examined the expression of PR and the enzymes responsible for progesterone biosynthesis (P450scc, 3betahydroxysteroid dehydrogenase, and steroidogenic acute regulatory protein) in human brain. We also examined the distribution of PR isoforms in neurogenic tumors using immunohistochemistry and RT-PCR analysis. The presence of PR and mRNA for P450scc, 3beta-hydroxysteroid dehydrogenase, and steroidogenic acute regulatory protein was detected in human brain. PR isoforms were detected in neurogenic tumors. PR-A and PR-B were equally expressed in meningiomas, but PR-B was the predominant isoform compared with PR-A in astrocytic tumors and Schwannomas. There was a statistically significant inverse correlation between PR-A and the proliferation index in meningiomas and astrocytic tumors. These findings suggest that progesterone is locally synthesized and exerts its actions through PR in the human central nervous system, and that progesterone may be involved in regulation of the growth and development of neurogenic tumors via PR, especially in the inhibition of tumor cell proliferation via PR-A.

Expression of urocortin and corticotropin-releasing factor receptor subtypes in the human heart.

Urocortin (Ucn) is a new member of the corticotropin-releasing factor (CRF) neuropeptide family and has positive inotropic actions and protective effects against ischemia in the rat heart. Ucn binds with very high affinity to both CRF receptor type 1 (CRF-R1) and CRF receptor type 2 (CRF-R2). However, to date, endogenous ligand(s) for CRF receptors expressed in the human heart have yet to be elucidated. In this study, we therefore examined the expression of Ucn and CRF receptors in human heart obtained at autopsy by RT-PCR, immunohistochemistry, and RIA. RT-PCR analysis demonstrated that Ucn and CRF-R2alpha mRNAs were detected in all four chambers. CRF-R1 mRNA was weakly present in some left atria, left ventricles, and in one right ventricle. CRF-R2beta mRNA was detected predominantly in the left atrium. CRF mRNA was not detected in any of the four chambers. Immunostaining for both Ucn and CRF receptors was detected in cardiac myocytes in all four chambers. Ucn-like immunoreactivity was detected in all four chambers by RIA, with the highest concentrations in the left ventricle (1.90 +/- 0.5 pmol/g wet weight, mean +/- SEM; n = 4). On the other hand, CRF-like immunoreactivity was very low or undetectable in the human heart. Sephadex G-50 column chromatography demonstrated that most of the Ucn-like immunoreactivity in the human heart was eluting earlier than the standard Ucn, with one minor peak in the position for Ucn. Ucn immunoreactivity was not detected in skeletal muscle by immunohistochemistry or RIA. These results suggest that Ucn is produced in the human heart and stored there mainly in the larger molecular weight forms. Endogenously produced Ucn may therefore exert its effects mostly through CRF-R2 in an autocrine and/or paracrine manner in the human heart.

Orexin-A expression in human peripheral tissues.

Orexin-A is a neuropeptide present in the brain and is known to regulate feeding and sleeping. In this study, we examined the systemic distribution of orexin-A in human tissues. Immunoreactivity for orexin-A was detected in ganglion cells of the thoracic sympathetic trunk, myenteric plexuses and endocrine cells of the gastrointestinal tract, islet cells of the pancreas and syncytiotrophoblasts and decidual cells of the placenta. In the gastrointestinal tract, orexin-A immunoreactivity was detected in the myenteric plexuses from 26 gestational weeks to birth. In double immunostaining in the pancreas, a great majority of insulin-positive cells was simultaneously positive for orexin-A. mRNA expression for prepro-orexin was also detected in the kidney, adrenal gland, pancreas, placenta, stomach, ileum, colon and colorectal epithelial cells. These results suggest the production of orexin-A in various human peripheral tissues and orexin-A may also play important roles in some peripheral organs.

The possible roles of mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type 2 in cardiac fibrosis in the spontaneously hypertensive rat.

In hypertension, aldosterone has been demonstrated to play a crucial role in cardiac fibrosis, which generally increases cardiac morbidity and death. However, few studies have reported the expression of the mineralocorticoid receptor (MR) and 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) in the heart under hypertensive conditions. Therefore, in this study, spontaneously hypertensive rats (SHR) were examined to elucidate the possible actions of mineralocorticoids via binding to MR. Wister Kyoto Rat (WKY), SHR, stroke-prone SHR (SHRSP), and malignant SHRSP (M-SHRSP) were used. Total RNA was extracted from the left ventricle of these rats, and examined for the expression levels of MR, 11beta-HSD2 and Collagen types 1 and 3 using reverse transcription real-time quantitative polymerase chain reaction employing the Light Cycler Instrument. Blood pressure was significantly different among each group. The mean mRNA levels for MR, 11beta-HSD2 and Collagen types 1 and 3 in M-SHRSP were found to be significantly increased compared to those of WKY, whereas no significant differences in mRNA levels were detected among SHR and SHRSP. Findings from the present study appear to demonstrate that MR and 11beta-HSD2 mRNA significantly rise in the left ventricle of M-SHRSP and increase of these mRNA is one of the cause of cardiac fibrosis.

TMPRSS2-ERG fusion is frequently observed in Gleason pattern 3 prostate cancer in a Canadian cohort.

PURPOSE: TMPRSS2-ERG gene fusion was recently reported as the most common gene rearrangement in prostate cancer (PCA). RESULTS: In this cohort 41% of the patients showed positive gene fusion status in their PCA. The TMPRSS2-ERG gene fusion status was homogenous within the same cancer focus and 82% of fusion positive PCA were present in GS 6 or 7 vs. 14% in GS 8 (p = 0.004). Moreover, TMPRSS2-ERG fusion was present in 42% of Gleason pattern 3 vs. 27% of Gleason pattern 4 (p = 0.014). However, in this study, no significant association was noticed between TMPRSS2-ERG fusion status in relation to pathological stage, surgical margin or biochemical failure. EXPERIMENTAL DESIGN: Using break-apart FISH assay to indirectly assess the fusion of TMPRSS2-ERG. We sought to characterize the incidence, pathological features and clinical parameters of TMPRSS2-ERG gene fusion in a cohort of 196 Canadian men treated by radical prostatectomy for localized PCA, and to investigate its potential as a biomarker in PCA. CONCLUSION: The higher association of TMPRSS2-ERG with Gleason score 6 and 7 should be further investigated. If confirmed, this could have significant clinical impact in further stratifying patients with PCA should the TMPRSS2-ERG be confirmed as a prognostic biomarker.

High-risk HPV/ErbB-2 interaction on E-cadherin/catenin regulation in human carcinogenesis.

Human papillomaviruses (HPVs) are a group of host-specific DNA viruses, with more than 120 different types identified to date. HPVs are classified as high- or low-risk (HR or LR) depending on their potential to induce cancer. Persistent infections with HR types of HPVs present a major risk factor for the development of a variety of human cancers including cervical, colorectal, head and neck as well as breast cancers. On the other hand, the deregulation of ErbB family tyrosine kinase receptors has also been associated with several types of human cancers. For instance, ErbB2 has been shown to have an important role in human carcinomas, specifically breast cancer. Moreover, the E-cadherin/catenin complex plays a pivotal role in the maintenance of normal adhesion in epithelial cells, and has been demonstrated to suppress tumor invasion and participate in cell signaling in human carcinomas. This review focuses on the interaction between HR-HPV/ErbB2 tyrosine receptors and the E-cadherin/catenin complex in human carcinomas including cervical, colorectal, head and neck and breast cancers.

Progesterone metabolism in human leukemic monoblast U937 cells.

Progesterone markedly inhibits the functions of human macrophages and T lymphocytes, and acts as an immunosuppressant during pregnancy. It is important to examine progesterone metabolites to understand the overall bioactive properties of this sex steroid. However, progesterone metabolism has not been examined in human immune cells. The human leukemic monoblast U937 cell line exhibits monocytic lineage and provides a valuable model to analyze monocyte-macrophage differentiation. Therefore, in this study, we analyzed progesterone metabolism in U937 cells by thin-layer chromatography. Progesterone was metabolized to 5alpha-pregnan-3beta,6alpha-diol-20-one via 5alpha-dihydroprogesterone and 5alpha-pregnan-3beta-ol-20-one, and 5alpha-pregnan-3beta,20alpha-diol was also detected as a final metabolic product via 20alpha-dihydroprogesterone and 5alpha-pregnan-20alpha-ol-3-one. 5alpha-reduction (5alpha-reductase type 1) and 20alpha-reduction were involved in the first step of metabolism. To identify the enzyme responsible for the 20alpha-reduction, we screened an U937 cDNA library, and obtained a clone (1.2 kb), which was identical to the human hepatic bile acid-binding protein or 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). 293 cells transfected with this cDNA demonstrated marked 20alpha-reduction of progesterone to 20alphaDHP, but 20alpha-oxidative, 3alpha-HSD or 17beta-HSD activity was found to be negligible. In experimental animals, the importance of 20alpha-HSD has been reported to be involved in the protection of immune cells from the toxic effects of progesterone. Therefore, our present data suggest that 20alpha-HSD plays an important role in the regulation of progesterone actions in human immune cells.

Expression of 11 beta-hydroxysteroid dehydrogenase type 1 in alveolar epithelial cells in rats.

11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) behaves predominantly as an oxoreductase converting the receptor-inactive glucocorticoids to their active forms in vivo, while the type 2 isoform (11beta-HSD2) possesses only dehydrogenase activity and inactivates cortisol in human or corticosterone in rat. We determined enzyme activity of 11beta-HSD in rat lungs from fetus to adult, and examined whether 11beta-HSD1 exists in alveolar type II cells, the most important site for the synthesis of pulmonary surfactant in mature lungs, by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Enzyme activity of 11beta-HSD1 and 2 in lung tissue homogenate were determined as NADP(+)- and NAD(+)-dependent conversion of corticosterone to 11-dehydrocorticosterone, respectively. We found that 11beta-HSD1 activity was increased progressively from 21 days gestation to 7 weeks after birth. 11beta-HSD2 activity was significantly lower than that of 11beta-HSD1 throughout gestation and after birth. Immunoreactivity for 11beta-HSD1 was detected in the cytoplasm of the cells in the alveolar region of adult rats. Some of these expressing 11beta-HSD1 were considered to be alveolar type II cells, because of their cuboid shape and localization at the corner of the alveoli. RT-PCR demonstrated 11beta-HSD1 mRNA in isolated alveolar type II cells. Our results suggest that alveolar type II cells enhance intracellular glucocorticoid availability via 11beta-HSD1. 11beta-HSD1 in alveolar type II cells is thought of as an autocrine amplifier of glucocorticoid action in the lung.

Differential expression of progesterone receptor isoforms A and B in the normal ovary, and in benign, borderline, and malignant ovarian tumors.

Human epithelial ovarian neoplasm is well-known to be sex steroid-related, but the possible biological significance of progesterone actions in these tumors remains controversial. In this study, we examined the differential expression patterns of the two progesterone receptor (PR) isoforms, PRA and PRB, using immunohistochemistry and real-time quantitative RT-PCR in normal and neoplastic ovarian tissues, and in cell lines derived from a normal ovarian surface epithelium and an ovarian epithelial carcinoma in order to further elucidate the possible involvement of progesterone in the development of ovarian neoplasms. The median H scores for PR isoforms in normal (n = 8), benign (n = 10), borderline (n = 8) and malignant (n = 24) ovarian tissues were as follows; PRA: 194.0, 171.0, 49.5, 0 (P < 0.05), and PRB: 175.0, 180.5, 251.5, 168.5, respectively. In ovarian cancer cell lines (OVCAR-3 and Caov-3), the PRB / PRAB mRNA ratio was increased by 17beta-estradiol, both time- and dose-dependently. However, this ratio was unaltered following the addition of 17beta-estradiol in a normal ovarian epithelial cell line (NOV-31). Immunoblotting analysis demonstrated that PRB protein expression was markedly up-regulated in OVCAR-3, whereas the PRA and PRB isoforms both appeared to be increased in NOV-31. These results suggest that down-regulation of PRA is associated with the development of ovarian epithelial carcinoma.

Retinoid receptors in the developing human lung.

Nuclear receptors and their ligands are known to play very important roles in lung development. Among these receptors, retinoid receptors, members of the steroid/thyroid hormone receptor superfamily, are classified into retinoic acid receptor (RAR) isoforms alpha, beta, and gamma and retinoid X receptor (RXR) isoforms alpha, beta, and gamma. In addition, isoforms I and II of the orphan receptor chicken ovalbumin upstream promoter-transcription factor (COUP-TF) have been shown to negatively regulate the activation of retinoid receptors. Both of these receptors have been shown to regulate lung development in the mouse. In the present study we utilized immunohistochemistry and real-time quantitative PCR to examine the expression of RAR-alpha, -beta and -gamma, RXR-alpha, -beta and -gamma and COUP-TFII in the human fetal lung at 13-16 gestational weeks, a very critical stage of human pulmonary development, in order to study possible roles in pulmonary morphogenesis by comparing these findings with those of the adult lung. RXR-gamma immunoreactivity was detected at both proximal (epithelia and mesenchyme of the trachea and bronchi associated with cartilage) and distal (epithelia and mesenchyme of smaller distal bronchi) sites in the fetal lung, but was markedly weaker in the adult lung. RAR-beta immunoreactivity was detected in distal mesenchymal cells of the fetal lung, but was not discernible in distal mesenchymal cells in the adult lung (bronchioles, alveolar ducts and alveolus). Relatively intense RAR-gamma immunoreactivity was detected in the chondrocytes of bronchial cells. COUP-TFII immunoreactivity was detected with a similar pattern to that of RAR-beta. Real-time quantitative PCR analyses revealed that mRNA levels of RXR-gamma at proximal and distal sites (ratio of fetal lung/adult lung: 3.4+/-0.05-fold and 3.1+/-0.03-fold respectively; P <0.01), RAR-beta at distal sites (2.4+/-0.01-fold; P <0.05) and RAR-gamma at proximal sites (2.2+/-0.11-fold; P <0.05) were significantly higher in the fetus than in the adult.

Sex steroid receptors in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a disease characterized primarily by chronic inflammatory synovitis and is well-known to be associated with significant sex differences in its prevalence and clinical features. Sex steroids have been proposed to be involved in the pathogenesis of RA, but details pertaining to the expression of sex steroid receptors in RA synovial tissue have yet to be fully characterized. In the present study, we examined oestrogen receptor (ER) alpha, ERbeta, progesterone receptor (PR) and androgen receptor (AR) mRNA expression using real-time reverse transcriptase-PCR (RT-PCR) in eight female RA synovial tissues and six female synovial tissues without inflammation, and determined immunolocalization of ERalpha, ERbeta, PR-A, PR-B and AR using immunohistochemistry in synovial tissues obtained from 22 RA patients. Real-time RT-PCR analysis demonstrated the expression of ER, PR and AR mRNAs in both RA and non-inflamed synovial tissues. Relative abundance of ER mRNAs was significantly higher in RA synovial tissue than non-inflamed synovial tissue (P<0.05). In addition, the relative ERalpha/ERbeta mRNA expression ratio was significantly lower in RA than non-inflamed synovial tissue (RA, 2.34 +/- 1.60; and non-inflamed, 20.7 +/- 19.1; P<0.05). There were no significant differences in relative abundance of PR mRNA. Relative abundance of AR mRNA was significantly lower in RA (P<0.05). Immunoreactivity for ERalpha, ERbeta, PR-B and AR was detected in the lining cells, inflammatory cells and fibroblasts in all the patients examined. The labelling indices for ERbeta and PR-B were more abundant in both lining cells (ERbeta, 54.2 +/- 12.2%; PR-B, 73.6 +/- 18.9%) and inflammatory cells (ERbeta, 74.6 +/- 16.2%; PR-B, 75.9 +/- 16.1%) than in fibroblasts (ERbeta, 36.5 +/- 15.6%; PR-B, 49.4 +/- 18.0%). Labelling indices for ERalpha and AR were significantly higher in lining cells (ERalpha, 14.4 +/- 8.6%; AR, 31.2 +/- 11.3%) and fibroblasts (ERalpha, 12.1 +/- 7.5%; AR, 20.1 +/- 9.6%) than those in inflammatory cells (ERalpha, 5.7 +/- 3.3%; AR, 9.2 +/- 4.4%). There were significant differences (P<0.05) in the labelling indices for ERalpha, ERbeta and PR-B between men and women under 50 years of age in fibroblasts of RA synovial tissues. These results indicate that sex steroid receptors are present in RA and non-inflamed synovial tissues, including inflammatory cells in RA, and suggest that sex steroids may play important roles in the regulation of inflammation of RA synovial tissue.

Dexamethasone upregulates 11beta-hydroxysteroid dehydrogenase type 2 in BEAS-2B cells.

The actions of natural and synthetic glucocorticoids are in part determined by 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2). We examined whether carbenoxolone, a potent inhibitor of 11beta-HSD, would potentiate the inhibitory action of dexamethasone on interleukin-8 release from BEAS-2B cells, and whether prolonged treatment with dexamethasone at therapeutic doses would upregulate 11beta-HSD2 in the cells. We found that carbenoxolone increased the potency of dexamethasone almost 10-fold. Reverse transcription-polymerase chain reaction and Western blot revealed that BEAS-2B cells expressed 11beta-HSD2, but not 11beta-HSD1. An enzyme activity assay of the cell homogenate demonstrated only NAD+-dependent dehydrogenase activity. The Km value for cortisol in intact BEAS-2B cells was estimated to be 42 nM. When the cells were incubated with dexamethasone for up to 72 hours at increasing concentrations (10(-9) to 10(-5) M), there were considerable increases in mRNA and protein levels of 11beta-HSD2. Prolonged treatment with dexamethasone also increased the enzyme activity of 11beta-HSD in the cells in a dose- and time-dependent manner, with complete inhibition by RU38486. These results suggest that bronchial epithelial cells possess an autoregulatory system for glucocorticoids in the control of their own bioactive levels by inducing the expression of 11beta-HSD2, and that 11beta-HSD2 in the bronchial epithelium may play a role in the local regulation of inhaled glucocorticoid actions.