Ai-Min Leng

Central South University, Ch’ang-sha-shih, Hunan, China

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Publications (4)4.87 Total impact

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    ABSTRACT: Primary liver cancer is one of the highly malignant tumours. The traditional surgery, chemotherapy and radiation therapy only established 6% of 5-year survival rate in HCC (hepatocellular carcinoma). Therefore there is an urgent need to develop new therapeutic strategies. HSP90 (heat shock protein 90) is one of the important molecular chaperones and was identified with high expression in the primary liver cancer. In this study, we evaluated the therapeutic effect of specific HSP90 inhibitor 17-DMAG (17-dimethylaminoethylamino-17-demethoxy geldanamycin) in HCC cells. The time and concentration effects of 17-DMAG were investigated in HCC cells. Cell proliferation was measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and cell counting. Apoptosis was detected by flow cytometry with staining of Annexin V-FITC/PI (propidium iodide). The protein levels of survivin, cyclin D1, p53 and NF-κB (nuclear factor κB) were measured by Western blotting. 17-DMAG inhibited the proliferation of HCC cells in a time- and concentration-dependent manner. Treatment with 400 nmol/l 17-DMAG for 48 h significantly induced early-stage apoptosis (22.4%). Conversely, it induced less late-stage apoptosis (3.03%). The 5 mg/l of cisplatin induced significantly less early-stage apoptosis (6.5%), but similar proportion of late-stage apoptosis (4.89%) compared with 17-DMAG. Inhibition of HSP90 activity by 400 nmol/l 17-DMAG decreased protein levels of survivin, cyclin D1 and NF-κB protein levels, whereas increased p53 protein level. HSP90 plays a key role in HCC cell growth and survival through regulation of survivin, cyclin D1, p53 and nucleus NF-κB protein levels and the specific HSP90 inhibitor 17-DMAG can play a therapeutic role in HCC treatment.
    Preview · Article · Jun 2012 · Cell Biology International
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    ABSTRACT: Pim-1 kinase is involved in the control of cell growth, differentiation and apoptosis. Recent evidence suggests that Pim kinases play a role in immune regulation and inflammation. However, the role of Pim-1 kinase in inflammatory bowel diseases (IBD) remains unclear. The aims of this study were to explore the role of Pim-1 kinase in the pathology of IBD and to assess whether inhibiting Pim-1 kinase may be of therapeutic benefit as a treatment regimen for IBD. Colitic mouse model was established by the induction of dextran sodium sulfate. The expression of Pim-1 in the colonic samples of control and colitic mice was examined. Furthermore, the mice were treated with Pim-1inhibitor (PIM-Inh), then the body weight and colon inflammation were evaluated, and the production of cytokines including IFN-γ, IL-4, TGF-β and IL-17 in colon tissues was determined by ELISA. The expression of T cell master transcription factors T-bet, ROR-γt, GATA-3 and Foxp3 and Nuclear factor κB (NF-κB) and inducible nitric oxide synthase in colon tissues was detected by real-time PCR and western blot. Finally, the effect of LPS on Pim-1 expression and the effects of PIM-Inh on LPS-induced upregualtion of p65 and TNF-α in RAW264.7 cells were examined by real-time PCR and western blot. Pim-1 expression was correlated with the degree of mucosal inflammation in vivo, and it was significantly induced by LPS in vitro. PIM-Inh had protective effects on acute colitis in vivo. Mechanistically, PIM-Inh reduced the proinflammatory immune response through the inhibition of the overactivation of macrophages and the down-regulation of excessive Th1- and Th17-type immune responses. Furthermore, PIM-Inh could skew T cell differentiation towards a Treg phenotype. Pim-1 kinase is involved in mucosal injury/inflammation and Pim-1 kinase inhibitor may provide a novel therapeutic approach for IBD.
    No preview · Article · Apr 2012 · Digestive Diseases and Sciences
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    ABSTRACT: This research aimed to construct a new combination gene vector: pcDNA3.1 (-)VEGF-siRNA/ yCDglyTK, study its expression quality and lethal effet in human gastric cancer cell line SGC7901. First, RNA interference (RNAi) targeting vascular endothelial growth factor (VEGF) was applied to construct interfering plasmid pGenesil-VEGF-siRNA. Then, the siRNA expression cassette (including U6 promotor ) was amplified by PCR and subcloned into pcDNA3.1 (-)CV-yCDglyTK to build a new combination gene plasmid: pcDNA3.1(-) VEGF-siRNA/yCDglyTK. The recombinant plasmid was identified by restriction enzyme digestion and gene sequencing. All of the three plasmids were delivered into SGC7901 cells using calcium phosphate nanoparticles (CPNPs). Expressions of yCDglyTK and VEGF were detected by RT-PCR and Western-blot. MTT assays were applied to determine the cytotoxic effect of plasmids in the presence of 5-FC. Restriction enzyme digestion and gene sequencing confirmed the combination gene vector pcDNA3.1 (-)VEGF-siRNA/yCDglyTK was constructed successfully. RT-PCR, Western-blot showed expression of yCDglyTK and inhibition of VEGF in SGC7901 cells transfected with the combined gene plasmid, which were the most sensitive to 5-FC in the MTT assays. The combination gene vector pcDNA3.1(-)VEGF-siRNA/yCDglyTK was constructed successfully. It was tentatively confirmed that RNAi targeting VEGF could synergize with suicide gene therapy.
    No preview · Article · May 2010 · Progress in Biochemistry and Biophysics
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    ABSTRACT: To evaluate the diagnostic valve of double balloon enteroscopy in patients with obscure abdominal pain and analyze the etiology of chronic abdominal pain resulted from enteral diseases. Sixty-seven cases with chronic abdominal pain underwent a previous negative gastroscopy, colonoscopy, gastrointestinal barium, B ultrasound and electrocardiogram were received double balloon enteroscopy during June 2005 to June 2008. Thirty-six of 67 patients was done by enteroscopy via anus, and 19 cases via oral, and 12 cases via both anus and oral. The lesions were found in 41 of the 67 patients, with overall diagnostic yield of 61.19%. Among 41 cases of abdominal pain resulted from small bowel diseases, Crohn's disease were found in 15 cases (36.59%), non-specific small enteritis in 10 cases (24.39%), tumors in 8 cases (19.51%), other enteral diseases in 8 cases (19.51%). Double balloon enteroscopy was a diagnostic modality with a high diagnostic value for obscure abdominal pain resulted from small bowel diseases. The most common causes of obscure abdominal pain were Crohn's disease, non-specific small enteritis and tumors.
    No preview · Article · Mar 2009 · Zhonghua nei ke za zhi [Chinese journal of internal medicine]