Qing Sheng - Academia.edu (original) (raw)

Papers by Qing Sheng

Advanced Materials Research, Aug 1, 2013

Journal of insect science (Online), 2015

Heat shock proteins (HSPs) are abundant and ubiquitous in almost all organisms from bacteria to m... more Heat shock proteins (HSPs) are abundant and ubiquitous in almost all organisms from bacteria to mammals. BmHSP20.8 is a small (sHSP) in Bombyx mori that contains a 561 bp open reading frame that encodes a protein of 186 amino acid residues with a predicted molecular mass of 20.8 kDa. The subcellular localization prediction indicated that BmHSP20.8 is likely distributed in the mitochondria with a 51% probability. To identify the subcellular localization of BmHSP20.8, three recombinant vectors were constructed and used to transfect BmN cells. The cytoplasmic and mitochondrial proteins were extracted 72 h after transfection. The Western blot showed that recombinant BmHSP20.8 exists only in the mitochondria. To locate the mitochondrial localization signal domain of BmHSP20.8 more accurately, we cloned four truncated recombinant vectors. The Western blot analysis of the cytoplasmic and mitochondrial proteins showed that the mitochondrial localization signal domain of BmHSP20.8 is located...

Cancer cell, Jan 13, 2015

Phosphoinositide-3-kinase (PI3K)-α inhibitors have shown clinical activity in squamous cell carci... more Phosphoinositide-3-kinase (PI3K)-α inhibitors have shown clinical activity in squamous cell carcinomas (SCCs) of head and neck (H&N) bearing PIK3CA mutations or amplification. Studying models of therapeutic resistance, we have observed that SCC cells that become refractory to PI3Kα inhibition maintain PI3K-independent activation of the mammalian target of rapamycin (mTOR). This persistent mTOR activation is mediated by the tyrosine kinase receptor AXL. AXL is overexpressed in resistant tumors from both laboratory models and patients treated with the PI3Kα inhibitor BYL719. AXL dimerizes with and phosphorylates epidermal growth factor receptor (EGFR), resulting in activation of phospholipase Cγ (PLCγ)-protein kinase C (PKC), which, in turn, activates mTOR. Combined treatment with PI3Kα and either EGFR, AXL, or PKC inhibitors reverts this resistance.

Acta diabetologica, 2014

MicroRNAs (miRNAs) play a crucial role in the pathogenesis of type 2 diabetes (T2D); they regulat... more MicroRNAs (miRNAs) play a crucial role in the pathogenesis of type 2 diabetes (T2D); they regulate several metabolic pathways including insulin secretion, glucose homeostasis, so their potential as biomarkers of diagnosis and prognosis has became increasingly appreciated. In this study, we explore serum miRNA profiles in T2D patients. A total of ten candidate miRNAs were identified by Solexa sequencing scanning and followed by a stem-loop quantitative reverse transcription PCR (qRT-PCR) to assess these candidate serum miRNAs. The results of qRT-PCR assessment revealed low serum levels of miR-23a, let-7i, miR-486, miR-96, miR-186, miR-191, miR-192, and miR-146a in T2D. Except for significantly lower in T2D and pre-diabetes patients compared with normal glucose tolerance (NGT) controls (P = 2.87E-05 and P = 3.75E-02), the levels of miR-23a demonstrated also significant decline in T2D patients compared with pre-diabetes patients (P = 1.06E-02). This marker yielded an AUC of 0.835 (95 %...

The International journal of biological markers

Cyclin B2 (CCNB2), a member of the cyclin protein family, has been found to be up-regulated in hu... more Cyclin B2 (CCNB2), a member of the cyclin protein family, has been found to be up-regulated in human cancers. To evaluate the potential use of circulating CCNB2 in serum in cancer surveillance, we examined relative expression levels of serum circulating CCNB2 mRNA in 103 cancer patients, 19 normal controls, and 40 benign disease patients using real-time quantitative reverse transcriptase polymerase chain reaction. We found that the relative expression level of circulating CCNB2 mRNA in cancer patients was significantly higher (p<0.0001) than that in normal controls and benign diseases group. Circulating CCNB2 mRNA level was significantly (p<0.001) correlated with cancer stage and metastasis status. Receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.87 and 0.83 (p<0.05) in identifying cancer patients' metastasis status in lung and digestive tract cancer, respectively. Moreover, we observed that expression levels of circulating CCNB...

Process Biochemistry, 2014

ABSTRACT It is important to study enzyme inhibition of α-glucosidase (EC 3.2.1.20) due to its cli... more ABSTRACT It is important to study enzyme inhibition of α-glucosidase (EC 3.2.1.20) due to its clinical relevance as a target enzyme for the treatment of type 2 diabetes mellitus. In this study, we investigated Co2+-induced inhibition as well as structural changes of α-glucosidase integrated with computational simulations. α-Glucosidase activity was inhibited by Co2+ in a dose-dependent manner. Co2+ inhibited α-glucosidase in a parabolic non-competitive inhibition reaction (Ki = 0.78 ± 0.08 mM) and directly induced regional unfolding of the enzyme resulting in a slight decrease in hydrophobic surface. The computational simulations using molecular dynamics showed that simulation with Co2+ resulted in a loss of secondary structure by positioning Co2+ near the active site for glucose production, implying that the Co2+ stimulate enzyme unfolding. Our study revealed the mechanism of Co2+ ligand binding mediated structural changes as well as inhibition of α-glucosidase activity, and suggested that Co2+ could act as a potent inhibitor of α-glucosidase for the treatment of type 2 diabetes mellitus.

Applied biochemistry and biotechnology, 2014

The E(spl)mγ gene in Drosophila is a regulatory target gene downstream of the Notch pathway. BmE(... more The E(spl)mγ gene in Drosophila is a regulatory target gene downstream of the Notch pathway. BmE(spl)mγ (Bombyx mori, E(spl)mγ) is an ortholog of the Drosophila E(spl)mγ gene, and the gene encodes a protein with 248 amino acid residues. This gene was cloned and overexpressed in Escherichia coli BL21(DE3). The recombinant protein was purified and subsequently used to generate a rabbit polyclonal antibody. Western blotting analyses showed that BmE(spl)mγ expression is high in pupa and egg, and low in larva and moth. In the fifth instar larva, the protein levels are high in head, epidermis, sexual gland, trachea, and the fatbody and low in the Malpighian tubule, hemolymph, gut, and silk gland. The further immunohistochemical analyses also showed higher BmE(spl)mγ expression in the head of fifth instar larva and pupa. Of the four moth parts studied, the thorax had the highest expression level. Thus, BmE(spl)mγ might be associated with neurogenesis in silkworm. Furthermore, DAPT (a γ-sec...

PLoS ONE, 2012

EMX2 is a human orthologue of the Drosophila empty spiracles homeobox gene that has been implicat... more EMX2 is a human orthologue of the Drosophila empty spiracles homeobox gene that has been implicated in embryogenesis. Recent studies suggest possible involvement of EMX2 in human cancers; however, the role of EMX2 in carcinogenesis needs further exploration. In this study, we reported that down-regulation of EMX2 expression was significantly correlated with EMX2 promoter hypermethylation in gastric cancer. Restoring EMX2 expression using an adenovirus delivery system in gastric cancer cell lines lacking endogenous EMX2 expression led to inhibition of cell proliferation and Wnt signaling pathway both in vitro and in a gastric cancer xenograft model in vivo. In addition, we observed that animals treated with the adenoviral EMX2 expression vector had significantly better survival than those treated with empty adenoviral vector. Our study suggests that EMX2 is a putative tumor suppressor in human gastric cancer. The adenoviral-EMX2 may have potential as a novel gene therapy for the treatment of patients with gastric cancer.

Oncogene, 2012

Ovarian cancer, the most deadly gynecologic malignancy, is often diagnosed late and at the advanc... more Ovarian cancer, the most deadly gynecologic malignancy, is often diagnosed late and at the advanced stage when the cancer cells have already migrated and invaded into other tissues and organs. Better understanding of the mechanism of metastasis in ovarian cancer cells is essential to the design of effective therapy. In this study, we investigated the function of scaffolding adaptor protein Gab2 in ovarian cancer cells. Gab2 is found to be overexpressed in a subset of ovarian tumors and cancer cell lines. Gab2 expression mainly regulates the migratory behaviors of ovarian cancer cells. Overexpression of Gab2 promotes the migration and invasion, and down-regulates Ecadherin expression in ovarian cancer cells with low-Gab2 expression. Conversely, knockdown of Gab2 expression inhibits the migration and invasion, and promotes E-cadherin expression in ovarian cancer cells with high-Gab2 expression. By expressing Gab2 wild type and Gab2 mutants that are defective in activation the PI3K and Shp2-Erk pathways, we find that Gab2 inhibits Ecadherin expression and enhances the expression of Zeb1, a transcription factor involved in epithelial-to-mesenchymal transition (EMT), and cell migration and invasion through the activation of the PI3K pathway. Knockdown of Zeb1 expression blocks Gab2-induced suppression of E-cadherin expression and increase in cell invasion. LY294002 and GDC-0941, inhibitors of PI3K, or Rapamycin, an inhibitor of PI3K downstream target mTOR, can reverse the effects of Gab2 on migration and invasion. Overall, our studies reveal that Gab2 overexpression, via activation of the PI3K-Zeb1 pathway, promotes characteristics of EMT in ovarian cancer cells.

Molecular and Cellular Biochemistry, 2014

Dysregulation of miR-452 has been observed in many tumors, but its biological function in hepatoc... more Dysregulation of miR-452 has been observed in many tumors, but its biological function in hepatocellular carcinoma (HCC) is still unknown. Our results showed that miR-452 expression is significantly increased in HCC tissues and HCC cell lines. We also found that overexpression of miR-452 dramatically accelerated proliferation, induced cell cycle from G1 to S transition, and blocked apoptosis of HCC cells. Migration and matrigel invasion assays indicated that miR-452 significantly promotes HepG2 and QGY-7703 cells migration and invasion in vitro. Further studies showed that miR-452 directly targets the 3&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-untranslated region of cyclin-dependent kinase inhibitor 1B (CDKN1B), ectopic miR-452 expression suppressed CDKN1B expression on mRNA and protein level. Silencing CDKN1B by small interfering RNA resembled the phenotype resulting from ectopic miR-452 expression. This study provides new insights into the potential molecular mechanisms that miRNA-452 contributed to HCC.

Journal of Biomedicine and Biotechnology, 2010

The human growth hormone (hGH) has been expressed in prokaryotic expression system with low bioac... more The human growth hormone (hGH) has been expressed in prokaryotic expression system with low bioactivity previously. Then the effective B. mori baculovirus system was employed to express hGH identical to mature hGH successfully in larvae, but the expression level was still limited. In this work, the hGH was expressed in B. mori pupae by baculovirus system. Quantification of recombinant hGH protein (BmrhGH) showed that the expression of BmrhGH reached the level of approximately 890 μg/mL pupae supernatant solution, which was five times more than the level using larvae. Furthermore, Animals were gavaged with BmrhGH at the dose of 4.5 mg/rat.day, and the body weight gain (BWG) of treated group had a significant difference (P < .01) compared with the control group. The other two parameters of liver weight and epiphyseal width were also found to be different between the two groups (P < .05). The results suggested that BmrhGH might be used as a protein drug by oral administration.

Chinese Journal of Chemical Engineering, 2007

A Lactobacillus brevis CGMCC 1306 isolated from fresh milk without pasteurization was found to ha... more A Lactobacillus brevis CGMCC 1306 isolated from fresh milk without pasteurization was found to have higher glutamate decarboxylase (GAD) activity. An effective isolation and purification procedure of GAD from a cell-free extract of Lactobacillus brevis was developed, and the procedure included four steps: 30%-90% saturation (NH 4 ) 2 SO 4 fractional precipitation, Q sepharose FF anion-exchange chromatography, sephacryl S-200 gel filtration, and resource Q anion-exchange chromatography. Using this protocol, the purified GAD was demonstrated to possess electrophoretic homogeneity via SDS-PAGE. The purification fold and activity recovery of GAD were 43.78 and 16.95%, respectively. The molecular weight of the purified GAD was estimated to be approximately 62 kDa via SDS-PAGE. The optimum pH and temperature of the purified GAD were 4.4 and 37℃, respectively. The purified GAD had a half-life of 50min at 45℃ and the K m value of the enzyme from Lineweaver-Burk plot was found to be 8.22. 5′-pyridoxal phosphate (PLP) had little effect on the regulation of its activity.

Cancer Research, 2013

We examined the effects of LJM716, an HER3 (ERBB3) neutralizing antibody that inhibits ligand-ind... more We examined the effects of LJM716, an HER3 (ERBB3) neutralizing antibody that inhibits ligand-induced and ligand-independent HER3 dimerization, as a single agent and in combination with BYL719, an ATP competitive p110α-specific inhibitor, against HER2-overexpressing breast and gastric cancers. Treatment with LJM716 reduced HER2-HER3 and HER3-p85 dimers, P-HER3 and P-AKT, both in vitro and in vivo. Treatment with LJM716 alone markedly reduced growth of BT474 xenografts. The combination of LJM716/lapatinib/trastuzumab significantly improved survival of mice with BT474 xenografts compared with lapatinib/trastuzumab (P = 0.0012). LJM716 and BYL719 synergistically inhibited growth in a panel of HER2+ and PIK3CA mutant cell lines. The combination also inhibited P-AKT in HER2-overexpressing breast cancer cells and growth of HER2+ NCI-N87 gastric cancer xenografts more potently than LJM716 or BYL719 alone. Trastuzumab-resistant HER2+/PIK3CA mutant MDA453 xenografts regressed completely after 3 weeks of therapy with LJM716 and BYL719, whereas either single agent inhibited growth only partially. Finally, mice with BT474 xenografts treated with trastuzumab/LJM716, trastuzumab/BYL719, LJM716/BYL719, or trastuzumab/LJM716/BYL719 exhibited similar rates of tumor regression after 3 weeks of treatment. Thirty weeks after treatment discontinuation, 14% of mice were treated with trastuzumab/LJM716/BYL719, whereas &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;80% in all other treatment groups were sacrificed due to a recurrent large tumor burden (P = 0.0066). These data suggest that dual blockade of the HER2 signaling network with an HER3 antibody that inhibits HER2-HER3 dimers in combination with a p110α-specific inhibitor in the absence of a direct HER2 antagonist is an effective treatment approach against HER2-overexpressing cancers.

BMC Genomics, 2008

Background: MicroRNAs (miRNAs) are small RNA molecules that regulate gene expression by targeting... more Background: MicroRNAs (miRNAs) are small RNA molecules that regulate gene expression by targeting messenger RNAs (mRNAs) and causing mRNA cleavage or translation blockage. Of the 355 Arthropod miRNAs that have been identified, only 21 are B. mori miRNAs that were predicted computationally; of these, only let-7 has been confirmed by Northern blotting.

Applied Mechanics and Materials, 2013

Applied Biochemistry and Biotechnology, 2009

A recombinant Bombyx mori profilin protein (rBmPFN) was overexpressed in Escherichia coli BL21. P... more A recombinant Bombyx mori profilin protein (rBmPFN) was overexpressed in Escherichia coli BL21. Purified rBmPFN was used to generate anti-BmPFN polyclonal antibody, which were used to determine the subcellular localization of BmPFN. Immunostaining indicated that profilin can be found in both the nucleus and cytoplasm but is primarily located in the cytoplasm. Real-time RT-PCR and Western blot analyses indicated that, during the larvae stage, profilin expression levels are highest in the silk gland, followed by the gonad, and are lowest in the fatty body. Additionally, BmPFN expression begins during the egg stage, increases during the larvae stage, reaches a peak during the pupa stage, and decreases significantly in the moth. Therefore, we propose that BmPFN may play an important role during larva stage development, especially in the silk gland.

Applied Biochemistry and Biotechnology, 2010

Using molecular approaches, a new member of the Bombyx mori small heat shock protein family was c... more Using molecular approaches, a new member of the Bombyx mori small heat shock protein family was cloned and characterized. The isolated gene contains an open reading frame of 672 bp, encodes a polypeptide of 223 amino acid residues with a predicted molecular mass of 25.4 kDa, and is therefore named BmHSP25.4. The gene codes for a protein homologous to the previously characterized HSP20.4 and HSP19.9. Western blotting analysis revealed that BmHSP25.4 existed in the fifth-instar larva's fatty body and blood tissues. Immunohistochemistry assay also showed that BmHSP25.4 was located in the fifth-instar larva's fatty body. The results of above studies have indicated constitutive expression of BmHSP25.4 in fatty body, blood tissues, and Bm5 cells. Finally, we examined the effect of heat stress on localization of BmHSP25.4 using anti-BmHSP25.4 polyclonal antibody by immunofluorescence. Under normal conditions, BmHSP25.4 was mostly found in the cytoplasm. However, after heat treatment, most of BmHSP25.4 distributed in the cell membrane. After 3 h of recovery following the heat shock treatment, the localization of BmHSP25.4 was the same as that under normal conditions.