Lin Pan

Ningbo University, Ning-po, Zhejiang Sheng, China

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Publications (4)9.16 Total impact

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    ABSTRACT: The let-7 family of microRNAs (miRNAs) are known to act as tumor suppressors and down-regulated in lung cancer. Recently, the RNA-binding protein Lin-28 was demonstrated to inhibit biogenesis of let-7 miRNAs by blocking both Drosha- and Dicer-mediated cleavage and accelerating decay of let-7 precursors. We selected NCI-H446 lung small cell lung cancer cell to determine whether it is broadly representative that Lin-28 can promote cell proliferation and affect cell cycle through negatively regulating let-7 biogenesis. Here, we showed that Lin-28 mRNA was up-regulated in NCI-H446 cell with a high c-Myc state. The result of real-time RT-PCR further indicated that pri-let-7a-1/7g and mature let-7g were remarkably down-regulated. The expression of lin-28 was down-regulated while the mature let-7g transcript was up-regulated inversely. The MTT assay indicated that the proliferation of lung cancer cells with lin-28 inhibition was signally impaired. The cells with lin-28 knockdown revealed a higher proportion of cells at G1/G0 phase and less at S phase. The results presented here demonstrate that induction of Lin-28 could mediate repression of let-7 family members, promote cell cycle progression and suppress cell proliferation.
    Molecular and Cellular Biochemistry 05/2011; 355(1-2):257-63. · 2.33 Impact Factor
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    ABSTRACT: Oral tolerance mediated by autoantigens has been applied successfully as a potential therapeutic strategy for preventing and treating autoimmune diseases. We previously showed cholera toxin B subunit (CTB) is an efficient mucosal carrier molecule for induction of systemic T cell tolerance to linked insulin antigens. In this study, we used an oral antigen consisting of a fusion protein composed of CTB and triple copies of glutamic acid decarboxylase 65 (GAD65) peptides 531-545 (3p531) to test its in vivo effect and investigate the mechanism of immune tolerance. Non-obese diabetic mice fed microgram quantities of the CTB-3p531 fusion protein showed a prominent reduction in pancreatic islet inflammation and a delay in the development of diabetes. Increased anti-GAD65 IgG1, serum IgA and unchanged IgG2a antibodies titers; together with an increase of IL-4, IL-10 production and a decrease of IFN-gamma production suggested possible activation of GAD65-specific Th2 immune responses. Adoptive transfer of splenocytes indicated oral administration of CTB-3p531 fusion protein generated potent regulatory cells that can suppress diabetogenic T cells. This study demonstrates the CTB-3p531 fusion protein protects against autoimmune diabetes by generation of regulatory T cells and induction of immunological tolerance.
    Vaccine 05/2010; 28(24):4052-8. · 3.77 Impact Factor
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    ABSTRACT: Cyclin-dependent kinase 2 (CDK2) is a member of serine/ threonine protein kinases, which initiates the principal transitions of the eukaryotic cell cycle and is a promising target for cancer therapy. The present study was designed to inhibit cdk2 gene expression to induce cell cycle arrest and cell proliferation suppression. Here, we constructed a series of RNA interference (RNAi) plasmids which can successfully express small interference RNA (siRNA) in the transfected human cells. The results showed that the RNAi plasmids containing the coding sequences for siRNAs down-regulated the cdk2 gene expression in human cancer cells at the mRNA and the protein levels. Furthermore, we found that the cell cycle was arrested at G0G1 phases and the cell proliferation was inhibited by different siRNAs. These results demonstrate that suppression of CDK2 activity by RNAi may be an effective strategy for gene therapy in human cancers.
    BMB reports 04/2010; 43(4):291-6. · 1.63 Impact Factor
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    ABSTRACT: Induction of specific immunological unresponsiveness by oral autoantigens such as glutamic acid decarboxylase 65 (GAD65) is termed oral tolerance and may be a potential therapy for autoimmune diabetes. However, the requirement for large amounts of protein will limit clinical testing of autoantigens, which are difficult to produce. Mucosal adjuvants such as cholera toxin B subunit (CTB) may lower the level of autoantigens required. Here we describe cloning, expression, purification and identification study of the CTB and triple GAD(531-545) epitopes fusion gene. The fusion gene was ligated via a flexible hinge tetrapeptide and expressed as a soluble protein in Escherichia coli BL21 (DE3) driven by the T7 promoter. We purified the recombination protein from the cell lysate and obtained approximately 2.5mg of CTB-GAD((531-545)3) per liter of culture with greater than 90% purity by a Ni-NTA resin column. The bacteria produced this protein as the pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB and GAD65. Further studies revealed that oral administration of bacterial CTB-GAD((531-545)3) fusion protein showed the prominent reduction in pancreatic islet inflammation in non-obese diabetic mice. The results presented here demonstrate that the bacteria bioreactor is an ideal production system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes.
    Protein Expression and Purification 05/2009; 66(2):191-7. · 1.43 Impact Factor