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Gang Li

Publications and source records attributed to Gang Li.

At least 127 records · Page 7Linked to original sources
PubMed2005

[Adeno-associated virus-mediated expression of human endostatin and its biological activity in vitro].

OBJECTIVE: To construct the recombinant adeno-associated viral vector containing human endostatin gene (rAAV-hEndo) and observe the biological activity of the expressed human endostatin in vitro. METHODS: rAAV-hEndo was prepared using a helper virus-free packaging system. The rAAV viral genome titer was quantified by Taqman real-time PCR, and the endostatin expressed in human umbilical vein endothelial cell line ECV304 was detected by immunofluorescence staining. The effects of endostatin on ECV340 cells were evaluated by MTT cell proliferation assay, cell cycle analysis and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) technique. RESULTS: The viral titer of rAAV-hEndo prepared was 2 x 10(12) vg/ml and the vector had an infection efficiency of 98%. Immunofluorescence staining showed that the human endostatin protein was expressed mainly in the cytoplasm of ECV304 cells, and the proliferation of the cells was obviously inhibited by the supernatant of rAAV-hEndo, with a inhibition rate of 67.3% 72 h after the addition of the supernatant. ECV304 cells infected with rAAV-hEndo were obviously arrested in G(1) phase, and the G(1)-phase cell percentage of treatment group were significantly higher than that of control group [(72.5+/-4.0)% vs (52.1+/-2.1)%, P<0.01]. ECV304 cells infected with rAAV-hEndo demonstrated markedly enhanced apoptosis, with a significantly greater apoptotic index than that of the control cells [(32.6+/-3.2)% vs (4.2+/-1.9)%, P<0.01]. CONCLUSION: rAAV-hEndo can effectively mediate the expression of biologically active human endostatin, which may facilitate further study of antiangiogenic gene therapy with endostatin for cancers.

Cell Proliferation↗
PubMed2005

[Identification of nm23-M2/NDPK B expression during the blastocyst adhesiveness in the mouse endomerium by two-dimentional electrophoresis and MALDI-TOF-MASS spectrometry].

The nm23 gene family was involved in cellular multiphysiopathological processes including differentiation, development, apoptosis and cancer promotion, progression or metastasis. Some data indicate that nm23 plays an important role in regulating reproductive processes. In the present study, we analyzed the proteome of the implantation sites and the peri-implantation sites in NIH. mice on Day 5 of gestation by using two-Dimensional gel electrophoresis (2-D PAGE), while the virgin mice as the control. A protein spot with pI 7.1, Mr 18 kDa showed up-regulated expression in endometrium during the blastocysts adhesiveness. Using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), this protein was identified as nm23-M2/NDPK B. The nm23-M2 expression in mice endometrium was shown progressive increase on Day 5 of gestation by RT-PCR, which was consistent with the result obtained by immunohistochemistry. These findings suggest that nm23-M2/NDPK B was involved in the process of blastocyst implantation.

Animals↗
PubMed2005

[Fusion expression, purification and bioassay of IFN-gamma inducible protein-10 and thioredoxin gene in E. coli].

Interferon gamma-inducible protein 10, a member of the family of CXC chemokines, is secreted by interferon gamma-stimulated, monocytes, endothelial cells and keratinocytes. Interferon gamma-inducible protein 10 plays an important role in recruiting activated T cells into sites of tissue inflammation. In this experiment, PCR products of Interferon gamma-inducible protein 10 were cloned into prokaryote expression vector pET 32(a) to generate recombinant pET-IP10 with S-Tag at the N-terminus, and expressed successfully in E. coli BL21 (DE3). The total expressed products amounted to 25.3% in all bacterion proteins. pET-IP10 mainly formed inclusion body in E. coli. Soluble recombinant protein accounted for 20% among IP-10 fusion protein. The soluble recombinant proteins were purified by using S-Tag affinity chromatography effectively with purity of over 90%. The chemotaxis biological activity of purified Interferon gamma-inducible protein 10 could specifically exhibit the directional migration of stimulated T cells at concentration of 100 ng/ml. The results indicated that the strategy we used in this experiment was effective for recombinant Interferon gamma-inducible protein 10 production with biological activity.

Chemokine CXCL10↗
PubMed2005

[Effect of full-length cyclin B1 antisense cDNA on chemosensitivity of lewis lung carcinoma cells to gemicitabine in vitro and in vivo].

OBJECTIVE: To evaluate the effect of full-length cyclin B1 antisense cDNA (AS-CLB1) on chemosensitivity of Lewis lung carcinoma cells (LL/2) to gemicitabine (GEM) in vitro and in vivo and hence provide a therapeutic regiment for treating non-small cell lung (NSCL) cancer using AS-CLB1 combined with GEM. METHODS: Cell cycle phase distribution and apoptosis of LL/2 parent cells, LL/2/vect and LL/2/AS-CLB1 transfectants (LP, LV and LA cells) were determined by flow cytometry. In addition, the three kinds of cells were treated with GEM (20 nmol/L-20 micromol/L) in vitro for 1 h and 24 h respectively, and then cytotoxicity of GEM was measured by MTT assay. After inoculation with the three kinds of cells respectively, the C57BL/6 mice were treated with GEM [25 - 125 mg/(kg x day)] once every three days for four times when tumors developed; tumorigenicity and survival were observed and cell apoptosis in tumor tissues was determined by flow cytometry. RESULTS: LA cells displayed apparent apoptosis and G1 arrest compared with LP and LV cells (controls). Additionally, cytotoxicity of GEM to LA cells was more obvious than that to controls. Moreover, tumorigenicity was inhibited, cell apoptosis in tumor tissues was induced, and survival was evidently increased in LA cells group. CONCLUSION: AS-CLB1 slightly increased the sensitivity of LL/2 cells to GEM in vitro and in vivo. The function of AS-CLB1 may be associated with its ability to enhance the anti-tumor activity of GEM by inducing cell apoptosis and G1 arrest.

Animals↗
PubMed2005

[Simultaneous determination of 25 persistent organic pollutants in rice by gas chromatography-mass spectrometry with selected ion monitoring mode].

A multi-residue analytical method for the simultaneous determination of persistent organic pollutants (POPs) in rice samples was developed. POPs were extracted from rice with ethyl acetate/n-hexane (80:20, v/v) by sonication, and determined by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode. A fused silica capillary column DB-35MS (30 m x 0.25 mm i.d. x 0.25 microm) was employed. Operating conditions were as follows: injector port temperature, 300 degrees C; column temperature, programming; carrier gas, helium; flow rate, 1.0 mL/min; sample size, 1 microL with splitless injection. The mass spectrometric detector (MSD) was operated in electron impact ionization mode with an ionizing energy of 70 eV. Analysis was performed with selected ion monitoring (SIM) using one target and one or two qualifier ion. POPs were confirmed by their retention times, their qualifier and target ions, and their qualifier/target abundance ratios. Recovery studies were performed at 0.05, 0.1, and 0.5 mg/L spiked levels of each POPs, and the recoveries obtained ranged from 81.99% to 100.60% with relative standard deviations between 2.37% and 18.48%. The detection limits of the method ranged from 0.1 to 5 ng/g for the different POPs except endrin, trans-chlordane and cis-chlordane. The results show that the method developed is sensitive and reliable.

Chlordan↗
PubMed2005

[Effective inhibition of EB virus-encoded latent membrane protein-1 by siRNA in EB virus (+) nasopharyngeal carcinoma cell].

OBJECTIVE: To evaluate the application of RNA interference in the study of latent membrane protein-1 (LMP-1) in EB virus-positive nasopharyngeal carcinoma (NPC) cell line C611. Observe the effects of LMP-1 silencing on NPC cell growth. METHODS: Four synthesized small interference RNA (siRNA) were transfected into NPC cell using Oligofectamine reagent. LMP-1 mRNA level was determined by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Flow cytometry and MTT assay were employed to analyze the effects on cell cycle and proliferation. RESULTS: The most effective sequence found out among the 4 candidates. Single dose of this siRNA caused nearly 90% loss of LMP-1 mRNA in C611 cell. The specific inhibition could last for 96 hours if re-transfection was preformed. LMP-1 siRNA treatment resulted in cell cycle arrest at G0-G1 stage in C611, accompany with a reduction of cell proliferation by 32.9%. While EBV-negative NPC cells appeared unaffected. CONCLUSIONS: These results provided solid testimony that EBV-encoded latent membrane protein-1 was vulnerable to RNA interference and, selective inhibition of LMP-1 had anti-proliferation effect on NPC cell. RNA interference could be a powerful tool in further investigations of LMP-1 and a novel therapeutic strategy for EBV-related NPC patients.

Cell Line, Tumor↗
PubMed2005

[Regulatory effect of Smad7 gene on MAPK signal pathway in malignant transformation of immortalized human bronchial epithelial BEP2D cells].

BACKGROUND & OBJECTIVE: Smad7 is an inhibitor of transforming growth factor-beta (TGF-beta) signal pathway. TGF-beta could induce the expression of several genes through activating SMAD and ras/MEK/ERK pathways. This study was to determine whether Smad7 is involved in regulating mitogen-activated protein kinase (MAPK) signal pathway with TGF-beta in malignant transformation of human bronchial epithelial BEP2D cells. METHODS: Immortalized BEP2D cells and malignant BERP35T2 cells were co-transfected with full-length Smad7 cDNA constructed pCISmad7.neo or Smad7 siRNA, transactivator vector pTet-Elk or pTet-Jun, and reporter vector pTRE-Luc, and stimulated with TGF-beta. The regulatory effect of Smad7 on MAPK signal pathway was investigated by standard luciferase assay. RESULTS: In BEP2D cells, when treated with TGF-beta1, phosphorylated activities of Elk and Jun were up-regulated (P(Elk)=0.033, P(Jun)=0.016); after co-transfection of Elk or Jun with pCISmad7.neo, phosphorylated activity of Elk was increased, and that of Jun was decreased (P(Elk)=0.017, P(Jun)=0.028); after co-transfection of Elk or Jun with Smad7 siRNA, phosphorylated activity of Elk was decreased, and that of Jun was increased (P(Elk)=0.018, P(Jun)=0.005). In BERP35T2 cells, when treated with TGF-beta1, phosphorylated activity of Elk was up-regulated (P=0.006); after co-transfection of Elk and Smad7 siRNA, phosphorylated activity of Elk was decreased (P=0.000); no activity of Jun was detected in BERP35T2 cells. CONCLUSIONS: In the process of malignant transformation of BEP2D cells, the intervention of Smad7 in MAPK signal pathway leads to the activity imbalance between extracellular signal-related protein kinase (ERK) and c-Jun NH2-terminal kinase (JNK), which in turn promotes cell proliferation. All these could contribute to further malignant transformation of these cells.

Bronchi↗
PubMed2005

Reuse rate of treated wastewater in water reuse system.

A water quality model for water reuse was made by mathematics induction. The relationship among the reuse rate of treated wastewater (R), pollutant concentration of reused water (Cs), pollutant concentration of influent (C0), removal efficiency of pollutant in wastewater (E), and the standard of reuse water were discussed in this study. According to the experiment result of a toilet wastewater treatment and reuse with membrane bioreactors, R would be set at less than 40%, on which all the concemed parameters could meet with the reuse water standards. To raise R of reuse water in the toilet, an important way was to improve color removal of the wastewater.

Bioreactors↗
PubMed2005

Expression and switching of TH1/TH2 type cytokines gene in human gliomas.

OBJECTIVE: To study the expression and switching of Th1/Th2 cytokines gene in human gliomas and its effects on occurring and developing of human gliomas. METHODS: Interleukin (IL)-2 and interferon-gamma represent Th1 type cytokines. IL-4, IL-6, IL-10, and IL-13 represent Th2 type cytokines. The gene expressions of Thl/Th2 cytokines in human glioma cells, glioma infiltrating lymphocytes, and glioma cell lines were detected by reverse transcription polymerase chain reaction (RT-PCR). The biological activity of cytokines in the supernatant of glioma cell lines was assayed by enzyme-linked immunosorbent assay (ELISA). RESULTS: The total positive rates of Th1 and Th2 type cytokines gene in human glioma cells were 14.77% and 75%. The total positive rates of Th1 and Th2 type cytokines gene in glioma infiltrating lymphocytes were 22.73% and 68.17%. There was obviously predominant expression of Th2 type cytokines in human glioma tissues, glioma infiltrating lymphocytes, and glioma cell lines. There was no unbalanced expression of Th1/Th2 cytokines in normal brain tissues. CONCLUSION: There is a predominant expression of Th2 type cytokines in human glioma cells. The switching of Thl/Th2 cytokines gene may play an important role in the occurring and developing of human gliomas.

Adolescent↗
PubMed2005

[Adeno-associated virus-mediated gene transfer of endostatin for inhibiting growth and metastasis of human nasopharyngeal carcinoma in nude mice].

OBJECTIVE: To investigate the inhibitory effect on growth and metastasis of human nasopharyngeal carcinoma in nude mice by adeno-associated virus-mediated gene transfer of human endostatin. METHODS: The infectious efficiency of recombinant adeno-associated virus (rAAV) in vitro was detected. The endostatin expressed in human umbilical vein endothelial cell ECV304 was detected by immunofluorescence staining. MTT was used to assay inhibitory effect of the infecting supernatant of recombinant adeno-associated viral vectors carrying human endostatin gene (rAAV-hEndo)on ECV304 cell. Heterotopic implantation model of human nasopharyngeal carcinoma cell C666-1 in nude mice was established. rAAV-hEndo or rAAV-EGFP or PBS were injected into the tail vein of tumor bearing mice. Three weeks after implantation, the volumes of tumor, inhibition rate, the percentage of lung metastases, microvessel density (MVD) and apoptotic index (AI) were evaluated respectively. RESULTS: The infectious efficiency of rAAV was 98% in vitro. Immunofluorescence staining showed the humam endostatin protein was expressed mainly in cytoplasm. ECV304 cell proliferation was obviously inhibited by the infecting supernatant of rAAV-hEndo. The inhibitory rate was 67.3% when the supernatant was used 72 h later. Compared with PBS group, the restrained percentage of tumor in hEndo group was 70.7%. The percentage of lung metastases in hEndo group, EGFP group and PBS group was 0.0%, 50.0% and 66.7% respectively. The average MVD of hEndo group (3.67 +/- 1.63) was significantly lower than that of EGFP group (19.67 +/- 2.16) and PBS group (22.50 +/- 3.02) (P < 0.01). The apoptotic index increased significantly in hEndo group(28.83 +/- 5.27)% versus EGFP group (6.17 +/- 2.79)% and PBS group (4.50 +/- 2.17)% (P < 0.01). The survival time of tumor bearing mice in hEndo group (36.50 +/- 8.46) d was significantly longer than EGFP group (24.00 +/- 5.66) d and PBS group (21.17 +/- 3.92) d (P < 0.01). CONCLUSIONS: The gene transfer of human endostatin mediated by adeno-associate virus can inhibit the growth and metastasis of human nasopharyngeal carcinoma in nude mice effectively. The mechanism may be due to the effect of antiangiogensis and inducement of tumor cell apoptosis.

Animals↗
PubMed2004

Morphine aggravates the apoptosis of simian immunodeficiency virus infected CEM x174 cells in the prolonged culture in vitro.

This study was designed to assess the in vitro effects of morphine on the lymphocytes infected with SIV. CEM x174 cells were cotreated with morphine and simian immunodeficiency virus (SIVmac239). Cells were cultured for 96 h and the effects of morphine on the viability of infected cells were determined. At the concentration of 1 micromol/l, morphine could inhibit the proliferation of CEM x174 cells at the culture of 72 h. The stronger effect was observed in the case of viral infection. During 72 h SIV loading, the cells were accumulated in S phase in all SIV infected groups. The S arrest was observed in every experimental group and statistically different from normal groups (P<0.05). The results from annexin V binding assay showed that SIV infection resulted in a lower proportion of vital cells and higher mortality compared with corresponding control (P<0.01). Morphine failed to induce detectable alteration in the cell cycle profile of viral infected cells. Western blotting showed that the synthesis of intracellular p53 and bax protein was gradually up-regulated in the virus-loading period of 72 h. Naloxone had an apparent additive rather than antagonistic effect on the morphine-associated enhancement of bax expression. The ratio of bax/bcl-2 proteins appeared to tilt the balance toward apoptosis. At 72 h of infection, 1 micromol/l of morphine significantly elevated the level of caspase-3. These results indicated that the alteration in the balance of intracellular apoptotic and anti-apoptotic elements is one of the reasons of accelerated progression of acquired immunodeficiency syndrome (AIDS) by opioids abuse.

Annexin A5↗
PubMed2004

The novel tumor suppressor p33ING2 enhances UVB-induced apoptosis in human melanoma cells.

The roles of p33ING2 as a tumor suppressor candidate have been shown through regulation of gene transcription, induction of cell cycle arrest, and apoptosis. As p33ING2 shares 58.9% homology with p33ING1b, we hypothesized that p33ING2 shares functional similarities with p33ING1b. We previously found that p33ING1b cooperates with p53 to enhance UVB-induced apoptosis. Here, we report that overexpression of p33ING2 enhanced apoptosis in UVB-irradiated and non-irradiated melanoma MMRU cells. We demonstrate that enhancement of apoptosis by p33ING2 requires the presence of functional p53. Furthermore, we found that overexpression of p33ING2 significantly downregulated the expression of Bcl-2 after UVB irradiation, resulting in an increased Bax/Bcl-2 ratio. Moreover, we found that p33ING2 promoted Bax translocation to mitochondria, altered the mitochondrial membrane potential, and induced cytochrome c release and thus the activation of caspases 9 and 3. In addition, we showed that under non-stress conditions p33ING2 upregulates Fas expression and activates caspase 8. Taken together, we demonstrate that p33ING2 cooperates with p53 to regulate apoptosis via activation of both the mitochondrial/intrinsic and death-receptor/extrinsic apoptotic pathways.

Apoptosis↗
PubMed2004

Effects of c-myb antisense RNA on TGF-beta1 and beta1-I collagen expression in cultured hepatic stellate cells.

AIM: To investigate the effects of c-myb antisense RNA on cell proliferation and the expression of c-myb, TGF-beta1 and beta1-I collagen in cultured hepatic stellate cells (HSC) from rats. METHODS: Recombinant retroviral vector of c-myb antisense gene (pDOR-myb) was constructed, and then transfected into retroviral package cell line PA317 by means of DOTAP. The pseudoviruses produced from the resistant PA317 cells were selected with G418 to infect HSCs isolated from rat livers. The cell proliferation was measured by 3-[4, 5-Dimethylthiazolzyl]-2, 5-diphenyl tetrazo-dium bromide(MTT) method. The expression of c-myb, alpha (1)-I collagen and TGF-beta1 mRNA, and c-myb protein in HSCs was detected with semi-quantitive reverse transeription-polymerase chain reaction (RT-PCR) and Western-blot respectively. RESULTS: HSCs from rats were isolated successfully with the viability >98%. In the pDOR-myb infected HSCs, the c-myb protein expression, cell proliferation,and alpha (1)-I collagen and TGF-beta1 mRNA expression were repressed significantly compared with their corresponding control groups (P<0.01). CONCLUSION: c-myb plays a key role in activation and proliferation of HSC. c-myb antisense RNA can inhibit cell proliferation, alpha (1)-I collagen and TGF-beta1 mRNA expression, suggesting that inhibition of c-myb gene expression might be a potential way for the treatment of liver fibrosis.

Animals↗
PubMed2004

New types of the flexible self-assembled metal-organic coordination polymers constructed by aliphatic dicarboxylates and rigid bidentate nitrogen ligands.

The reaction of metal ions, flexible aliphatic dicarboxylates and rigid bidentate linear ligands under mild conditions in water afford four novel metal-organic coordination polymers, [Cd(mu-mal)(mu-pyz)(0.5)(H(2)O)](n) 1 (mal = malonate dianion, pyz = pyrazine), [Cd(2)(mu-suc)(2)(mu-pyz)(H(2)O)(2)](n) 2 (suc = succinate dianion), and ([M(mu-bipy)(H(2)O)4][suc].4H(2)O)(n)(M = Co, 3, M = Zn, 4, bipy = 4,4'-bipyridine). The molecular structures of 1-4 have been established by single-crystal X-ray crystallography. 1 is a 3D network being composed of layers of octahedrally coordinated Cd atoms bridged by malonate anions in syn-anti configurations within the layers and pyz molecules between layers. Unlike that in 1, each Cd atom in 2 displays uncommon pentagonal-bipyramidal geometry to form 2D infinite grid sheets with square grid dimensions of ca. 7.936 x 7.936 [Angstrom]. Both 3 and 4 exhibit 1D linear -M-bipy-M-bipy- chain polymers, and these chains were packed as ...ABCABC... layered structures. The bridging succinate ligands in 2 adopt the syn-anti mode with a torsion angle of 60.8(7) degrees, while the solvated succinate ligands in 3 and 4 adopt the anti-anti mode with a torsion angle of 180.0 degrees. To our knowledge, compound 2 represents the first example of flexible self-assembled succinate-pyrazine mixed bridging ligand coordination network. 3 and 4 are the first two cases of succinate-bipy polymers with non-coordinated succinate. The magnetic behavior for 3 was studied in the temperature range of 5-300 K. The result indicates the occurrence of a weak antiferromagnetic coupling between the cobalt(II) ions.

Journal Article↗
PubMed2004

Mutational analysis of the nuclease domain of Escherichia coli ribonuclease III. Identification of conserved acidic residues that are important for catalytic function in vitro.

The ribonuclease III superfamily represents a structurally distinct group of double-strand-specific endonucleases with essential roles in RNA maturation, RNA decay, and gene silencing. Bacterial RNase III orthologs exhibit the simplest structures, with an N-terminal nuclease domain and a C-terminal double-stranded RNA-binding domain (dsRBD), and are active as homodimers. The nuclease domain contains conserved acidic amino acids, which in Escherichia coli RNase III are E38, E41, D45, E65, E100, D114, and E117. On the basis of a previously reported crystal structure of the nuclease domain of Aquifex aeolicus RNase III, the E41, D114, and E117 side chains of E. coli RNase III are expected to be coordinated to a divalent metal ion (Mg(2+) or Mn(2+)). It is shown here that the RNase III[E41A] and RNase III[D114A] mutants exhibit catalytic activities in vitro in 10 mM Mg(2+) buffer that are comparable to that of the wild-type enzyme. However, at 1 mM Mg(2+), the activities are significantly lower, which suggests a weakened affinity for metal. While RNase III[E41A] and RNase III[D114A] have K(Mg) values that are approximately 2.8-fold larger than the K(Mg) of RNase III (0.46 mM), the RNase III[E41A/D114A] double mutant has a K(Mg) of 39 mM, suggesting a redundant function for the two side chains. RNase III[E38A], RNase III[E65A], and RNase III[E100A] also require higher Mg(2+) concentrations for optimal activity, with RNase III[E100A] exhibiting the largest K(Mg). RNase III[D45A], RNase III[D45E], and RNase III[D45N] exhibit negligible activities, regardless of the Mg(2+) concentration, indicating a stringent functional requirement for an aspartate side chain. RNase III[D45E] activity is partially rescued by Mn(2+). The potential functions of the conserved acidic residues are discussed in the context of the crystallographic data and proposed catalytic mechanisms.

Alanine↗
PubMed2004

Two-stage adaptive strategy for superiority and non-inferiority hypotheses in active controlled clinical trials.

In active controlled trials without a placebo arm, there are usually two study objectives: to test a superiority hypothesis that the experimental treatment is more effective than the active control therapy, and to test a non-inferiority hypothesis that the experimental treatment is therapeutically no worse than the active control within a defined margin. For a two-stage adaptive design, it is not necessary to give a fixed sample size calculation at the planning stage of the study when treatment effect information is often insufficient. Instead, decision and estimation of the design specifications can be made more reliably after the first stage when interim results are available. We propose the use of conditional power approach to determine the sample size and critical values for testing the superiority and non-inferiority hypotheses for the second stage based on the observed result of the first stage. The proposed adaptive procedure preserves the overall type I error rate for both superiority and non-inferiority, and has the flexibility of early termination of the study (for futility or efficacy) or extending the study by appropriate sample size.

Controlled Clinical Trials as Topic↗