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Biomedical subjects

Xia Wang

Publications and source records attributed to Xia Wang.

At least 73 records · Page 4Linked to original sources
PubMed2004

A hybrid protein of the amino-terminal fragment of urokinase and mutant plasminogen activator inhibitor-2 efficiently inhibits tumor cell invasion and metastasis.

The urokinase plasminogen activator(uPA) system plays important roles in tumor cell invasion and metastasis. In the present study, we evaluated the effects of ATF-PAI2CD, a hybrid protein of the amino-terminal fragment of urokinase and mutant plasminogen activator inhibitor-2, on 95D cells in vitro and in vivo. Furthermore, our results support a current hypothesis that fusion protein blocks tumor invasion and motility by inhibiting localized pericellular proteolysis. Treatment of 95D cells with ATF-PAI2CD resulted in a dose-dependent decrease in tumor-cell invasion through matrigel, and ATF-PAI2CD was much more effective than PAI-2CD. In addition, extracellular regular protein kinase (ERK1/2) expression was downregulated and the adhesion ability to fibronectin was increased in 95D cells treated with the fusion protein, which was confirmed by cell adhesion assay. A high-concentration of ATF-PAI2CD caused a significant reduction in tumor volume and weight in BALB/c (nu/nu) mice female inoculated with human 95D cells (5 x 10(6)); the antitumor effects were significant, which demonstrated a 67.9+/-4.2% reduction in tumor growth compared with control mice. The number of lymphatic metastasis was significantly reduced in mice treated with high- and middle- concentrations of ATF-PAI2CD, whereas a low-concentration of ATF-PAI2CD failed to exhibit any antimetastatic effects. In conclusion, the results suggested that the hybrid protein has therapeutic potential for lung carcinoma and other tumors to inhibit tumor invasion and metastasis.

Animals↗
PubMed2004

Morpho-regulation of ectodermal organs: integument pathology and phenotypic variations in K14-Noggin engineered mice through modulation of bone morphogenic protein pathway.

Ectodermal organs are composed of keratinocytes organized in different ways during induction, morphogenesis, differentiation, and regenerative stages. We hypothesize that an imbalance of fundamental signaling pathways should affect multiple ectodermal organs in a spatio-temporal-dependent manner. We produced a K14-Noggin transgenic mouse to modulate bone morphogenic protein (BMP) activity and test the extent of this hypothesis. We observed thickened skin epidermis, increased hair density, altered hair types, faster anagen re-entry, and formation of compound vibrissa follicles. The eyelid opening was smaller and ectopic cilia formed at the expense of Meibomian glands. In the distal limb, there were agenesis and hyperpigmentation of claws, interdigital webbing, reduced footpads, and trans-differentiation of sweat glands into hairs. The size of external genitalia increased in both sexes, but they remained fertile. We conclude that modulation of BMP activity can affect the number of ectodermal organs by acting during induction stages, influence the size and shape by acting during morphogenesis stages, change phenotypes by acting during differentiation stages, and facilitate new growth by acting during regeneration stages. Therefore during organogenesis, BMP antagonists can produce a spectrum of phenotypes in a stage-dependent manner by adjusting the level of BMP activity. The distinction between phenotypic variations and pathological changes is discussed.

Animals↗
PubMed2004

Interaction of plasminogen activator inhibitor-2 and proteasome subunit, beta type 1.

The apoptosis protection by plasminogen activator inhibitor -2(PAI-2) is dependent on a 33 amino acids fragment between helix C and D of PAI-2 which is probably may be due to the interaction of PAI-2 with unknown intracellular proteins. In this study we used the fragment between helix C and D of PAI-2 as bait to screen a HeLa cells cDNA library constructed during apoptosis in a yeast two-hybrid system and retrieved a clone that encodes 241 amino acids of proteasome (prosome, macropain) subunit, beta type 1(PSMbeta1) which plays important roles in NF-kappaB activation. GST-pulldown experiments confirmed the interaction between PAI-2 and PSMB1 in vitro. These data suggest that the antiapoptosis activity of PAI-2 is probably related to its interaction with PSMbeta1.

Amino Acid Sequence↗
PubMed2004

Antisense Tiam1 down-regulates the invasiveness of 95D cells in vitro.

As a specific guanine nucleotide exchange factor of Rac1, Tiam1 (T-lymphoma invasion and metastasis inducing protein 1) is involved in a number of cellular events, such as cytoskeleton reorganization, cell adhesion, and cell migration. Since Tiam1 was implicated in the invasion and metastasis of T-lymphoma cells and breast tumor cells, we compared the expression level of Tiam1 in two human giant-cell lung carcinoma cell strains with high or low metastasis potential, and found that Tiam1 expression level in high-metastatic 95D cells was higher than that in low-metastatic 95C cells. To further confirm the role of Tiam1 in invasion and metastasis, we constructed the antisense Tiam1 expression plasmid (pcDNA3-anti-Tiam1), which was transfected into 95D cells. A stable transfected clone with decreased Tiam1 expression was screened and selected for further research. Transwell assay showed that down-regulation of endogenous Tiam1 by anti-Tiam1 can reduce the in vitro invasiveness of 95D cells. Our results suggested that Tiam1 signaling contributed to the invasion and metastasis of the human giant-cell lung carcinoma cells.

Base Sequence↗
PubMed2004

Endogenous regulators of protein phosphatase-1 during mouse oocyte development and meiosis.

Reversible phosphorylation, involving protein kinases and phosphatases (PP), is important in regulating oocyte meiosis. Okadaic acid (OA) inhibition of PP1 and/or PP2A stimulates oocyte germinal vesicle breakdown (GVB). In oocytes, PP1 is localized in the cytoplasm and nucleus, yet endogenous regulation of oocyte PP1 has not been investigated. The objectives of the study were to identify intra-oocyte mechanisms regulating PP1 during acquisition of OA-sensitive meiotic competence and meiotic resumption. Immunohistochemical studies revealed that GVB-incompetent oocytes contained equivalent cytoplasmic and nuclear PP1. Upon development of OA-sensitive meiotic competence, PP1 displayed differential intracellular localization with significantly greater nuclear staining with distinct nucleolar rimming compared with cytoplasmic staining. Germinal vesicle-intact oocytes contained neither nuclear inhibitor of PP1, nor PP1 cytoplasmic inhibitor-1 transcripts or proteins. Reverse transcription-PCR with PP1 cytoplasmic inhibitor-2 (I2) primers and oocyte RNA amplified a predicted 330-bp product with the identical sequence to mouse liver I2. Oocytes contained a heat-stable PP1 inhibitor with biochemical properties of I2. Phosphorylation of PP1 at Thr320 by cyclin dependent kinase-1 (CDK1) causes PP1 inactivation. Germinal vesicle-intact oocytes did not contain phospho-Thr320-PP1. Upon GVB, PP1 became phosphorylated at Thr320 and this phosphorylation did not occur if GVB was blocked with the CDK1 inhibitor, roscovitine (ROSC). Inhibition of oocyte GVB with ROSC was reversible and coincided with PP1 phosphorylation at Thr320. Increased oocyte staining of nuclear PP1 compared with cytoplasmic staining at a chronological stage when oocytes gain meiotic competence, and phosphorylation and inhibition of PP1 by CDK1 at or around GVB appear to be important mechanisms in regulating oocyte PP1 activity and meiosis. In addition, these studies provide further support for PP1 being the OA-sensitive PP important in the regulation of the acquisition of meiotic competence, nuclear events during meiotic arrest, and GVB.

Animals↗
PubMed2004

[Preliminary study on preparation and pharmaceutic features of adrimycin-loaded human serum albumin microspheres].

OBJECTIVE: To prepare adrimycin-loaded human serum albumin microspheres(ADR-HSA-MS) and to study its pharmaceutic properties and in vitro cytotoxicity. METHODS: ADR-HSA-MS, consisting of ADR and HSA, were prepared by emulsion heating solidification method and its morphology was observed by optical microscopy and scanning electron microscopy. Pepsin digestion method was used for determining drug loading of ADR-HSA-MS and membrane diffusion technique for detection of in vitro release of ADR from the microspheres. MTT colorimetric assay was used to determine cytotoxicity of ADR-HSA-MS for human hepatoma SMMC-7721 cell line. RESULTS: ADR-HSA-MS looked like smooth red spheres with an average diameter of 1.2 microns and had an apparent drug-loading of 2.73% or an effective drug-loading of 1.69%. Its peak of the accumulated drug-releasing fraction was 65%, and 50% of ADR releasing from the MS would take five days, which suggested a slow release of ADR from the albumin microspheres. ADR-HSA-MS exerted remarkable cytotoxicity to human hepatoma SMMC-7721 cells with dose-dependence at a range of ADR concentration from 0.3 microgram/ml to 2.5 micrograms/ml when incubated with the target cells for four days. Its killing curve was similar to that of free ADR. CONCLUSION: Emulsion heating solidification method could be used for preparation of adrimycin-loaded human serum albumin microspheres with sustained release property.

Antibiotics, Antineoplastic↗
PubMed2004

[Mandibular contour sculpture by osteotomy].

OBJECTIVE: To investigate the method for mandible osteotomy in order to make the mandible of various square face appear harmony. METHODS: According to different types of the mandible, mandible angle osteotomy was performed in combination with mandible edge, mandible half ring osteotomy or chin augmentation. RESULTS: A total of 312 cases have been treated since 1996. In this series, mandible angle and mandible edge osteotomy was performed in 200 cases; only mandible edge osteotomy in 23; mandible half ring osteotomy in 15, chin sharpening in 9, chin augmentation with autogenous bone implantation, in 32. Postoperative follow-up of 150 cases for 1-12 months showed that the satisfactory rate was 97%. CONCLUSION: Integrated mandible osteotomy can make the square face look natural and nice-looking.

Humans↗
PubMed2004

[Speciation and distribution characters of rare earth elements in the Baotou Section of the Yellow River].

As a whole of water column, suspended matter and surface sediment in the mainstream and the branch taking up industry wastewater, speciation and distribution characters of rare earth elements (REEs) were investigated systemically in the Baotou section of the Yellow River. This study shows that rare earth elements in the mainstream of the Baotou section of the Yellow River mainly exist in suspended particles, and the dissolved contents are in extremely minute quantities. REEs mainly exist in dissolved particles in the branch taking up industry wastewater, and suspended sigma REE and dissolved sigma REE are obviously higher than those in the mainstream. The change of sigma REE of dissolved particles in water phase along the Baotou section of the Yellow River is very similar to that of sigma REE of suspended particles, and consistent along the main river, it is that sigma REE increase appreciably from the control profile to the keystone discharged section, come to a head in the D site and reduce in the E site. This distribution pattern indicates pile industry wastewater of Baotou to rare earth elements in the mainstream of the Yellow River, particularly LREE. The REE distribution in the mainstream of the Baotou section of the Yellow River is the same, with LREE enrichment and Eu depletion. But LREE origin of D site is different from the other sites by excursion of LREE distribution curve and other geochemical parameters, they are origin of industry wastewater piled, otherwise the other four sites are origin of loess altiplano. And HREE are origin of loess altiplano in all the sites. The speciation characteristics of REE in the sediments and suspended matter are quite similar with the amount in as follows: residual >> bound to carbonates, bound to Fe-Mn oxides > bound to organic matter >> exchangeable. REEs exchangeable in surface sediment and suspended matter in the branch taking up industry wastewater are higher than those in the mainstream, it confirms that REEs in the mainstream mainly exist in suspended particles, and mainly exist in dissolved particles in the branch.

Geologic Sediments↗
PubMed2004

[Effects of the site and method of liposuction on differentiation of human preadipocytes].

OBJECTIVE: To illustrate the effects of the site and method of liposuction on differentiation of human preadipocytes. METHODS: Forty-two fatty samples were obtained with liposuction, which were then divided into four groups according to operation sites (abdomen, hip or extremity) and the methods (conventional negative-pressure or syringe method). Each sample was treated with collagenase I to release preadipocytes for in vitro culture. Affected by the differentiation-induced agents for 9 days or 28 days, the cultured adipocytes were stained with Nile red and observed under a fluorescent microscope. The differentiation rates were examined with flow cytometric analysis and the quantity of intracytoplasmic lipids was determined with oil red O staining. The results were analyzed with independent samples t-test (Mann-Whitney) using SPSS 10.0. RESULTS: There was no statistical difference in differentiation at the 9th day or 28th day among the preadipocytes obtained from the abdomen, hip or extremity with the negative-pressure method. The preadipocytes from the abdomen differentiated more at the 28th day than the 9th day (P < 0.05), which was not observed in the hip or the extremity. The preadipocytes obtained from the abdomen with the negative-pressure method differentiated more than those with the syringe method (P < 0.05). CONCLUSION: No essential difference was found in preadipocyte differentiation among the liposuction sites, while the abdomen might have some superiority. The negative-pressure method of liposuction is the first option in future research of tissue engineering. The flow cytometric analysis is a convenient way to study preadipocyte differentiation.

Abdomen↗
PubMed2004

[Cloning, ligation and expression of the variable region genes of the monoclonal antibody against human HnRNPA2/B1].

OBJECTIVE: To clone the variable region genes of the monoclonal antibody (McAb) against human heterogeneous nuclear ribonucleoprotein A2/B1 (HnRNPA2/B1), ligate them to assemble single chain Fv (ScFv) gene and express in Escherichia coli. METHODS: The specificity of the anti-HnRNPA2/B1 McAb 3E8 to synthetic HnRNPA2/B1 peptide, HnRNPA2/B1 protein in lung cancer cells were examined by dot-immunobinding assay, Western blot and immunohistochemistry. The variable region genes of heavy chain (VH) and light chain (VL) were amplified from hybridoma cell by reverse transcription-polymerase chain reaction(RT-PCR), and then were linked by a linker peptide using SOE-PCR (splicing by overlap extension-PCR) to construct recombination ScFv gene. The latter was cloned into the expression vector pET28 (a+) and expressed in E coli BL21. The expressed product was identified by SDS-PAGE and competitive ELISA inhibition test. RESULTS: It was shown that the McAb combined specifically with synthetic HnRNPA2/B1 peptide and HnRNPA2/B1 protein in three lung cancer cells. The cloned VH gene and VL gene were 345 bp and 309 bp respectively and were linked successfully to obtain ScFv gene. The ScFv protein was expressed in the form of inclusion body, with molecular weight of 28,000 and immunoreactivity to HnRNPA2/B1. CONCLUSION: VH gene, VL gene and ScFv gene of anti-HnRNPA2/B1 antibody were cloned, constructed and functionally expressed in E coli. These results provide the experimental basis for elucidating the role of HnRNPA2/B1 in lung cancer.

Adenocarcinoma↗
PubMed2003

Conformation of CCAAT/enhancer-binding protein alpha dimers varies with intranuclear location in living cells.

The structure of a protein defines its biochemical properties, but the impact of intracellular location and environment on protein structure remains poorly defined. CCAAT/enhancer-binding protein alpha (C/EBPalpha) is a master regulator of transcription and cellular proliferation that concentrates and is kept inactive at transcriptionally quiescent, pericentromeric regions in mouse cell nuclei. C/EBPalpha dimer structure was measured in living cells from the amounts of fluorescence energy transferred between derivatives of the green fluorescent protein attached to different C/EBPalpha domains. Comparing the levels of fluorescence resonance energy transfer at pericentromeric and nonpericentromeric regions of the nucleus indicated that the DNA binding domains of C/EBPalpha dimers were further apart and interacted more poorly at pericentromeric heterochromatin than in the more euchromatic regions of the nucleus. In contrast, the position and interactions of the transcriptional activation domains were similar throughout the nucleus. Phorbol ester treatment caused a shift in the position of the transcriptional activation domain relative to the DNA binding domain. Thus, C/EBPalpha conformation varies with intranuclear location and with cellular environment. These "fluorescence resonance energy transfer nanoscopy" techniques will be broadly applicable for associating conformational and kinetic variations to subcompartment-specific actions of C/EBPalpha or any protein in the dynamic intracellular environment.

3T3 Cells↗
PubMed2003

Glycogen synthase kinase-3 regulates mouse oocyte homologue segregation.

Intracellular regulation of oocyte meiosis is not completely understood. However, reversible phosphorylation, which involves serine/threonine protein kinases and phosphatases (PP), is an important mediator. Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase. Currently no reports exist on presence or function of GSK-3 in mammalian oocytes. The aim of this study was to determine GSK-3 presence/absence, transcript and protein expression, intracellular protein distribution, and to investigate the functional importance of GSK-3 in mouse oocyte meiosis. Germinal vesicle-intact (GVI) oocytes contained both GSK-3 transcript and protein. Although GSK-3 beta-isoform is the only transcript identifiable in GVI oocytes, both alpha- and beta-isoforms were recognized by Western blot analysis. In growing, meiotic-incompetent oocytes GSK-3 was present, diffusely located throughout the cytoplasm and absent in the nucleus, whereas in meiotic-competent oocytes this cytoplasmic GSK-3 displays a predominant peri-oolemma staining. Treatment of mouse GVI oocytes with lithium chloride (LiCl), which inhibits both inositol monophosphatase (IMPase) and GSK-3, had no significant influence on oocyte viability, morphology, or development to metaphase II (MII). However, LiCl caused abnormal spindle formation and significantly increased incidence of abnormal homologue segregation during the first meiotic division. L690,330, which is a specific IMPase inhibitor, had no significant effect on oocyte viability, morphology, MII development, or homologue segregation. This is the first report of GSK-3 in mammalian oocytes. LiCl inhibition of mouse oocyte GSK-3 modified organization of microtubules and/or function of meiotic spindles thus compromising segregation of condensed bivalent chromosomes.

Animals↗
PubMed2003

Specific inhibition of mouse oocyte nuclear protein phosphatase-1 stimulates germinal vesicle breakdown.

Okadaic acid (OA)-induced germinal vesicle breakdown (GVBD) and localization of protein phosphatase-1 (PP1) in oocyte nuclei are suggestive of PP1's role in regulating oocyte GVBD. To explore this possibility, we microinjected protein phosphatase (PP) inhibitors OA, anti-PP1 antibody (anti-PP1), PP1 inhibitor I2, and anti-PP2A antibody (anti-PP2A) into nuclei of roscovitine (ROSC)-arrested mouse oocytes. Oocytes were also injected with recombinant PP1 in the absence of ROSC. Oocytes were assessed for GVBD and metaphase II (MII) development at 2 and 18 hr post-injection. Data were analyzed using Cochran-Mantel-Haenszel Statistics adjusted for time. Microinjection of OA significantly enhanced GVBD in comparison to controls at 2 and 18 hr (P < 0.01), yet had no effect on MII development. Similarly, microinjection of anti-PP1 resulted in significantly higher levels of GVBD compared to controls at 2 and 18 hr (P < 0.01). Interestingly, anti-PP1 microinjection also tended to enhance MII development at 18 hr in comparison to controls (P < 0.09). Microinjection of I2, anti-PP2A, and PP1 had no effect on GVBD or MII development. If reduction of PP1 activity was important for GVBD, one would anticipate an endogenous means of regulating PP1 activity at this developmental stage. In somatic cells, phosphorylation of PP1 at Thr320 causes PP1 inactivation. Germinal vesicle-intact oocytes did not contain phosphorylated PP1, as determined using a specific Thr320-Phospho-PP1 antibody, Western blot analysis, and confocal immunocytochemistry. At or around the time of GVBD, oocyte PP1 became phosphorylated at Thr320, which remained phosphorylated through MII development. These data indicate that inhibition of intra-nuclear PP1, through specific antibody neutralization, mimics OA-stimulated GVBD, providing the first direct evidence that nuclear PP1 is involved in regulation of oocyte nuclear membrane integrity. In addition, phosphorylation of PP1 occurs at/or around GVBD indicating that inactivation of PP1 is an important intracellular event in regulation of nuclear envelope dissolution at GVBD.

Animals↗
PubMed2003

Oxidative stress is associated with increased apoptosis leading to spermatozoa DNA damage in patients with male factor infertility.

OBJECTIVE: To evaluate ejaculated spermatozoa from patients with male factor infertility for the role of cytochrome c and caspases 9 and 3 (the proteins known to mediate apoptosis) and to examine association between semen quality and apoptosis in the presence of oxidative stress. DESIGN: Prospective study. SETTING: Male infertility clinic at a tertiary health care center. PATIENT(S): Semen specimens from 35 patients with idiopathic infertility and 8 normal healthy donors. MAIN OUTCOME MEASURE(S): Levels of ROS, cytochrome c, and caspases 9 and 3 and semen variables. RESULT(S): Compared with normal donors, infertile patients had significantly higher levels (expressed as median [25th and 75th percentiles]) of ROS (4.15 x 10(6) counted photons per minute [cpm] [0.26, 40.16 x 10(6) cpm] vs. 0.06 x 10(6) cpm [0.02, 0.29 x 10(6) cpm]; P<.01), cytochrome c (2.78 [2.21, 43.65 vs. 1.5 [1.25, 2.2]; P<.01)], caspase 9 (2.52 [0.9, 4.28] vs. 6 [4.85, 7.63]; P<.006), and caspase 3 (0.56 [0.32, 1.02] vs. 1.69 [1.66, 2.67]; P<.01). Semen variables (motility, concentration, and morphology) were negatively correlated with caspase 9 and 3 (P<.05). Reactive oxygen species was positively correlated with cytochrome c (r=.43; P<.03), caspase 9 (r=.56; P<.001), and caspase 3 (r=.65;P<.01). CONCLUSION(S): Infertile men have decreased sperm variables induced by higher ROS levels in semen. A positive relationship exists between increased sperm damage by ROS and higher levels of cytochrome c and caspases 9 and 3, which indicate positive apoptosis in patients with male factor infertility.

Apoptosis↗