Stanniocalcin 1 induction by thyroid hormone depends on thyroid hormone receptor β and phosphatidylinositol 3-kinase activation

CONTEXT

Thyroid hormone (TH) mediated changes in gene expression were thought to be primarily initiated by the nuclear TH receptor (TR) binding to a thyroid hormone response element in the promoter of target genes. A recently described extranuclear mechanism of TH action consists of the association of TH-liganded TRβ with phosphatidylinositol 3-kinase (PI3K) in the cytosol and subsequent activation of the PI3K pathway.

OBJECTIVE

The aim of this study was to examine the effect of TH, TRβ and PI3K on stanniocalcin 1 (STC1) expression in human cells.

DESIGN

We treated human skin fibroblasts with triiodothyronine (T3) in the absence or presence of the PI3K inhibitor LY294002, a dominant negative PI3K subunit, Δp85α, and the protein synthesis inhibitor cycloheximide (CHX). The role of the TRβ was studied in cells from patients with resistance to thyroid hormone (RTH). STC-1 mRNA expression was measured by real-time PCR.

RESULTS

We found an induction of STC1 by T3 in normal cells, but less in cells from subjects with RTH (2.7 ± 0.2 vs. 1.6 ± 0.04, P < 0.01). The effect of T3 was completely abrogated by blocking PI3K with LY294002 (3.9 ± 0.5 vs. 0.85 ± 0.5; P < 0.05) and greatly reduced after transfection of a dominant negative PI3K subunit, demonstrating dependency on the PI3K pathway.

CONCLUSION

These results establish STC1 as a TH target gene in humans. Furthermore, we show that STC1 induction by TH depends on both TRβ and PI3K activation.

Purification and characterization of a new D-galactose-specific lectin from the housefly, Musca domestica, and its antiproliferative effect on human K562 and MCF-7 tumor cells

In the present work, a D-galactose-specific lectin with novel N-terminal sequence was purified from Musca domestica L. (Diptera: Muscidae) pupae. The purification was performed using affinity chromatography, ultra-filtration, and HPLC. The haemagglutinating activity of M. domestica lectin was specifically inhibited by D-galactose. The haemagglutinating activity of this lectin was stable at temperatures up to 65 degrees C and in pH ranging from 4 to 8. Salts including FeCl(3) and MnCl(2) inhibited the haemagglutinating process, whereas NaCl, KCl, CaCl(2), MgCl(2), ZnCl(2), and AlCl(3) did not. By SDS-PAGE, purified M. domestica pupae lectin yielded a single band with a molecular weight of 40 kDa, with or without reduction of beta-mercaptoethanol, and it could be stained with Alcian Blue 8 GX. The morphology of purified lectin was observed by atomic force microscopy, which indicated that M. domestica lectin was an 8.27 nm high, globular shaped glycoprotein with a 1.41 nm high polysaccharide chain. In addition, antiproliferative activity of this lectin against tumor cells K562 and MCF-7 was determined with a colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, which showed that the antiproliferative process was time- and dose-dependent with an IC(50) of 5.7 and 6.7 at 24 h, 5.5 and 6.4 at 36 h, 5.2 and 6.5 microM at 48 h, respectively.

The neuronal repellent SLIT2 is a target for repression by EZH2 in prostate cancer

The neuronal repellent SLIT2 is repressed in a number of cancer types primarily through promoter hypermethylation. SLIT2, however, has not been studied in prostate cancer. Through genome-wide location analysis we identified SLIT2 as a target of Polycomb group (PcG) protein EZH2. The EZH2-containing Polycomb repressive complexes bound to the SLIT2 promoter inhibiting its expression. SLIT2 was down-regulated in a majority of metastatic prostate tumors exhibiting a negative correlation with EZH2. This repressed expression could be restored by methylation inhibitors or EZH2-suppressing compounds. In addition, a low level of SLIT2 expression was associated with aggressive prostate, breast and lung cancers. Functional assays showed that SLIT2 inhibited prostate cancer cell proliferation and invasion. Thus, this study demonstrated for the first time epigenetic silencing of SLIT2 in prostate tumors, and supported SLIT2 as a potential biomarker for aggressive solid tumors. Importantly, PcG-mediated repression may serve as a precursor for the silencing of SLIT2 by DNA methylation in cancer.

Pharmacokinetics of methyl protodioscin in rats

Methyl protodioscin (MPD), a natural furostanol saponin, showed distinct antitumor activity and is distributed in many traditional Chinese medicines. The pharmacokinetics, distribution and excretion of MPD were first investigated after i.v. injection to rats in this study. The dose-dependent pharmacokinetics of MPD were characterized after i.v. injection (20, 40 and 120 mg/kg of MPD) to rats. A good linearity (r = 0.9989, P < 0.05) was found in the regression analysis of the AUC0-t -dose. The plasma concentrations of MPD declined rapidly with an elimination half-life (t1/2) from 25.56 to 29.32 min. The MPD kinetics was in line with one-compartment model after i.v. injection. 23.43% and 32.86% of MPD was recovered in urine and bile, respectively. The concentrations of MPD in plasma and most examined tissues 5 h after injection were close to or below the Low Limit of Quantification (LLOQ). This indicated that MPD was distributed and eliminated rapidly in rats.

Purification of lectin from larvae of the fly, Musca domestica, and in vitro anti-tumor activity in MCF-7 cells

A new lectin was purified from larvae of the fly, Musca domestica L. (Diptera: Muscidae) (MLL-2, 38 kDa) using affinity chromatography and HPLC. Anti-tumor activity of MLL-2 was demonstrated by its inhibition of proliferation of human breast cancer (MCF-7) cells in a time-and dose-dependent manner. The results of acridine orange staining indicated that MLL-2 caused apoptosis in MCF-7 cells. DNA fragmentation in MCF-7 cells has been detected by TUNEL. Flow cytometric analysis also demonstrated that MLL-2 caused dose-dependent apoptosis of MCF-7 cells through cell arrest at G2/M phase. The MLL-2 induced a sustained increase in concentration of intracellular free calcium. Western blot revealed that MLL-2 induced apoptosis in MCF-7 cells was associated with typical apoptosis proteins in the mitochondrial pathway. In addition, the caspase-3 activity in MCF-7 cells treated with MLL-2 for 48 hours was significantly increased compared to controls (407.4 ± 3.0 vs. 1749.2 ± 6.0, P <0.01). Since MLL-2 induced apoptosis in MCF-7cells the mitochondrial pathway may be the main pathway of antitumor activity.

Purification and characterization of a new D-galactose-specific lectin from the housefly, Musca domestica, and its antiproliferative effect on human K562 and MCF-7 tumor cells

In the present work, a D-galactose-specific lectin with novel N-terminal sequence was purified from Musca domestica L. (Diptera: Muscidae) pupae. The purification was performed using affinity chromatography, ultra-filtration, and HPLC. The haemagglutinating activity of M. domestica lectin was specifically inhibited by D-galactose. The haemagglutinating activity of this lectin was stable at temperatures up to 65 degrees C and in pH ranging from 4 to 8. Salts including FeCl(3) and MnCl(2) inhibited the haemagglutinating process, whereas NaCl, KCl, CaCl(2), MgCl(2), ZnCl(2), and AlCl(3) did not. By SDS-PAGE, purified M. domestica pupae lectin yielded a single band with a molecular weight of 40 kDa, with or without reduction of beta-mercaptoethanol, and it could be stained with Alcian Blue 8 GX. The morphology of purified lectin was observed by atomic force microscopy, which indicated that M. domestica lectin was an 8.27 nm high, globular shaped glycoprotein with a 1.41 nm high polysaccharide chain. In addition, antiproliferative activity of this lectin against tumor cells K562 and MCF-7 was determined with a colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, which showed that the antiproliferative process was time- and dose-dependent with an IC(50) of 5.7 and 6.7 at 24 h, 5.5 and 6.4 at 36 h, 5.2 and 6.5 microM at 48 h, respectively.

Regeneration of foreign genes co-transformed plants of Medicago sativa L by Agrobacterium rhizogenes

Gene encoding sulphur amino acid-rich protein (HNP) and rol genes were transferred into Medicago sativa L (alfalfa) mediated by Agrobacterium tumafeciens. Regeneration of transgenic plants was induced successfully from hairy root tissue of cotyledon in alfalfa. Cotyledon tissues were an ideally transformed recipient. There was a negative correlation between age of hairy roots and embryogenesis frequency in alfalfa. Production of co-transformed plants with greater yield and super quality was important for development of new alfalfa varieties.

New mutations in the transglutaminase 1 gene in three families with lamellar ichthyosis

BACKGROUND

Autosomal recessive lamellar ichthyosis (LI) is a severe skin disorder characterized by generalized hyperkeratosis. Gene mutation in transglutaminase 1 (TGM1), which mediates cross-links in the formation of the cell envelope during terminal differentiation of epidermis, has been identified as a cause of LI.

OBJECTIVES

To determine mutations of TGM1 gene in three Chinese families with LI.

METHODS

The TGM1 gene was sequenced to identify disease-causing mutations in the three families with LI. One of the results was confirmed by using reverse transcriptase PCR and in situ hybridization. An in situ transglutaminase (TGase) 1 assay was performed to estimate TGase 1 activity in the patients' skin.

RESULTS

Four novel mutations of keratinocyte TGase1 (Q203X, D254N, R687H and IVS4 + 1G-->T) were found in the three families. No TGase 1 mRNA was detected in patient skin using RT-PCR and in situ hybridization, and the in situ TGase assay showed that there was no or decreased TGase 1 activity in patient skin.

CONCLUSIONS

Our findings suggest that four novel mutations in TGM1 gene result in decrease or absence of TGase activity in the skin and, as a consequence, cause the phenotype of LI.

BNIP3L (Nix) expression in colon cancer

e15097

Background: Microenvironmental adaptation to hypoxic conditions is critical for a cell to survive in a growing solid tumor. BNIP3L (Nix) mediates apoptosis during hypoxia in cancer cell lines, and Nix knockdown promotes tumor growth in-vivo through decreased apoptosis and increased proliferation, suggesting a means by which cells can adapt. Little is known specifically about Nix expression and its importance in human colon cancer. To gain insight into expression of this gene in colon tumors, the present study analyzed mRNA microarray data from 227 colon tumors and 22 normal colon tissue samples and queried differential expression of Nix. These results were compared to the protein levels present in human colon tumors. Methods: mRNA expression of 227 human colon tumors (made available by the Expression Project for Oncology (expO)) and 22 normal colon samples (retrieved from the Gene Expression Omnibus (GEO)) was analyzed. These samples were hybridized to the Affymetrix GeneChip Human Genome U133 Plus 2.0 Array, assaying 17,726 NCBI Entrez genes. Immunohistochemistry was performed on human tissue microarray CO701 (US Biomax, Inc.) containing 62 tumor samples. Results: Nix mRNA levels were shown to increase from normal to cancer (log-fold change of 0.961, Benjamini-Hochberg FDR adjusted p < 0.001). IHC demonstrated variable levels of Nix present in colon tumors: 38/62 (61.3%) of tumors stained positive for Nix while 24/62 (38.7%) were negative. Conclusions: We have shown that mRNA levels of Nix are upregulated in the transition from normal colon tissue to cancer but that protein levels in tumors demonstrate variable expression. This suggests that silencing of Nix occurs at various stages of tumorigenic progression and results in isolated populations of cells within a growing tumor that are uniquely resistant to apoptosis. Better understanding of Nix in the context of a growing colon tumor is needed and could lead to development of more successful therapeutics.

No significant financial relationships to disclose.

False-positive diagnosis of breast cancer by diffused optical tomography with ultrasound

e22085

Background: Breast cancer is one of the most common cancer in women. Early detection, early diagnosis and early treatment play key role in fighting against breast cancer. OPTIMUS system is a system of diffused optical tomography with ultrasound. It provides dual modality images for early diagnosis of breast cancer. The aim of this study was to evaluate the OPTIMUS system on diagnosis of breast disease. Methods: OPTIMUS system was applied to 160 breast tumor patients. All patients had received surgical treatment and had definite pathological diagnosis. OPTIMUS system was evaluated as diagnostic tool of breast tumor in this study. Results: There were 42 cases diagnosed as benign breast disease and 118 cases diagnosed as breast cancer by OPTIMUS system. Pathology confirmed 60 cases of benign disease and 100 cases of breast cancer. False positive rate of breast cancer was 30% (18/60). False negative rate of breast cancer was 0% (0/100). The pathology of false positive cases was mild and severe papillomatosis (6/18), non-typical hyperplasia (4/18), chronic inflammation (3/18), fibroadenoma (3/18) and fat necrosis (2/18). Papillomatosis and non-typical hyperplasia are precancerous lesions and often difficult for clinical diagnosis. In this study the false positive diagnostic rate of mammography and ultrasonography is 13% and 11.1% respectively. Conclusions: OPTIMUS system is a non- invasive and highly effective diagnostic tool for breast disease. Its sensitivity is reached to 100% and specificity is about 70% on the diagnosis of breast cancer. OPTIMUS system could be used as assistant diagnostic tool for breast tumor.

No significant financial relationships to disclose.

Molecular characterisation of outbreak-related strains of vancomycin-resistant Enterococcus faecium from an intensive care unit in Beijing, China

We investigated an outbreak of vancomycin-resistant Enterococcus faecium affecting 14 patients in a 20-bed intensive care unit (ICU) between September 2006 and August 2007 (incidence: 3.56 cases per 1000 ICU patient days). Eighteen isolates of vanA type E. faecium were analysed by pulsed field gel electrophoresis, which showed 14 types overall. Multilocus sequence typing (MLST) identified eight different sequence types (STs) (ST78, ST117, ST203, ST316, ST362, ST363, ST364 and ST365), including four new types (ST362, ST363, ST364 and ST365) and 17 strains belonged to clonal complexes CC17. Sixteen of these carried the esp gene. Eighteen Tn1546-like elements encoding vanA-type VRE were classified into three types (types I to III) and all of them contained both IS1216V and IS1542 insertions. Vancomycin resistance of 14 vanA type E. faecium isolates was transferred at a frequency of 1.3 x 10(-6) to 6.4 x 10(-5) between E. faecium strains during filter mating. Our findings indicate that conjugative dissemination of Tn1546-like elements among CC17 E. faecium occurred during the outbreak in this ICU.

Screening and characterization of monoclonal antibodies to the surface antigens of Listeria monocytogenes serotype 4b

AIMS

This study aims to develop and characterize monoclonal antibodies (Mabs) with high specificity and affinity for surface antigens of an epidemiologically important serotype 4b of Listeria monocytogenes.

METHODS AND RESULTS

Hybridoma clones were derived from B lymphocytes of mice immunized with L. monocytogenes serotype 4b and screened against this strain by an enzyme-linked immunosorbent assay. Twenty-nine clones secreting Mabs reactive with formalin-killed bacteria were obtained; 15, 8, 5 and 1 Mabs were immunoglobulin subclasses IgG2a, IgG2b, IgM and IgG1, respectively. Immunofluorescence or immunogold labelling demonstrated all except five IgM and one IgG2a Mabs bound to the surface of a live L. monocytogenes serotype 4b. The majority of the 23 surface-binding Mabs recognized linear epitopes on a 77-kDa protein. These surface-binding Mabs exhibited little or no cross-reactivity with non-4b serotypes (1/2a, 1/2b, 3a, etc.) of L. monocytogenes, five other Listeria species, Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium.

CONCLUSIONS

The Mabs recognizing a 77-kDa surface protein are novel antibodies with specificity and affinity for L. monocytogenes serotype 4b.

SIGNIFICANCE AND IMPACT OF THE STUDY

These anti-77 kDa surface protein Mabs may be explored as reagents for the development of Mabs-based diagnostic immunoassays for L. monocytogenes serotype 4b strains.

212 EFFECTS OF VASCULAR ENDOTHELIAL GROWTH FACTOR ON THE EARLY DEVELOPMENT AND POLYSPERMY RATE OF OVINE EMBRYOS PRODUCED IN VITRO

To investigate the effect of vascular endothelial growth factor (VEGF) on the early development and polyspermy rate of ovine embryos in vitro, 2 experiments were conducted with human recombinant VEGF165 supplemented to the media during maturation, fertilization, and culture in vitro, respectively. Ovaries were collected from ewes at a local slaughterhouse. All oocytes surrounded by a multilayer of cumulus cells were collected and rinsed 3 times in maturation medium (control medium and treatment medium, respectively). A total of 100 oocytes in each group were cultured in 4-well plates (Nunc) containing 800 μL of maturation medium at 38.5°C in an atmosphere of 5% CO2 with saturated humidity. Four replicates of each experiment were conducted. Statistical analyses were conducted by ANOVA with SPSS 12.0 software (SPSS Inc., Chicago, IL, USA). Data are expressed as means, and P < 0.05 was considered significant. In Experiment 1, to investigate the effect of VEGF on the early development of ovine embryos in vitro, VEGF was used at 5 ng mL–1 (treatment group A) and 10 ng mL–1 (treatment group B) in maturation medium (TCM-199 + BSA), HSOF fertilization medium, and SOF culture medium. The results showed that the maturation rate was increased significantly (P < 0.01), from 75.76% in the control treatment to 83.98 and 80.23% in treatment group A and treatment group B, respectively. The cleavage rate was increased from 75.85% in the control group to 79.39% in treatment group A (P > 0.05). The development rates of morulae (45.03%) and blastocysts (23.54%) in treatment group A were significantly higher (P < 0.01) than those in the control group (38.94 and 18.09%, respectively). In addition, the development rates of blastocysts in treatment group B (21.05%) were lower than those in treatment group A (P > 0.05) and higher than those in the control group (P > 0.05). In Experiment 2, to investigate the effect of VEGF on the polyspermy rate of ovine embryos in vitro, 5 ng mL–1 of VEGF was used in TCM-199 + BSA maturation medium in this experiment. The results showed that the fertilization rate after 18 h of IVF was increased significantly (P < 0.01), from 75.75% in the control group to 83.86% in the treatment group, and that the polyspermy rate was decreased significantly (P < 0.01), from 12.64% in the control group to 7.68% in the treatment group. These results indicate that VEGF significantly improved the maturation and fertilization rates of ovine oocytes and, consequently, the rate of embryo development in vitro, especially when the medium was supplemented with 5 ng mL–1 of VEGF. The VEGF obviously decreased the polyspermy rate and bated the phenomenon of polyspermy in the process of ovine oocyte IVF. The present study was supported by the National Natural Science Foundation of China (No. 30371035).

Therapeutic effects on experimental metastatic tumor-bearing mice by vaccination with GM-CSF gene-modified and tumor antigen-pulsed macrophages

Macrophages, with potent cytotoxic and antigen-presenting activities, can be used in cancer treatment. The biological characteristics and antitumor effect of GM-CSF gene-modified and tumor antigen-pulsed macrophages were investigated. The high levels of GM-CSF could be detected in the supernatants of macrophages after gene transfer. The cytotoxicity and the expression of MHC class II molecules of the gene-modified macrophages increased significantly and the antigen-presenting ability was enhanced. The gene-modified macrophages were then pulsed with tumor antigen and used to treat the experimental pulmonary metastastic mice. The number of pulmonary metastases was reduced significantly and the cytotoxicity of the CTL induced from the splenocytes of the tumor-bearing mice also increased. The results demonstrated that adenovirus-mediated GM-CSF gene transfer can activate macrophages to some extent and GM-CSF gene-modified, antigen-pulsed macrophages may be a new type of effective effector cells in the immunogene therapy of cancer.