PTEN and PDCD4 are bona fide targets of microRNA-21 in human cholangiocarcinoma / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the expression profile of microRNA-21 in human cholangiocarcinoma tissues and to validate its bona fide targets in human cholangiocarcinoma cells.</p><p><b>METHODS</b>The expression profile of microRNA-21 in human cholangiocarcinoma tissues and cholangiocarcinoma cell line, QBC939, was evaluated by using real-time PCR analysis. The bona fide targets of microRNA-21 were analyzed and confirmed by dual luciferase reporter gene assay and western blot, respectively. The expressional correlation of microRNA-21 and its targets was probed in human cholangiocarcinoma tissues by using real-time PCR, locked nucleic acid in situ hybridization (LNA-ISH), and immunohistochemistry analysis.</p><p><b>RESULTS</b>Real-time PCR analysis revealed that microRNA-21 expression depicted a significant up-regulation in human cholangiocarcinoma tissues about 5.6-fold as compared to the matched normal bile duct tissues (P<0.05). The dual luciferase reporter gene assay revealed endogenous microRNA-21 in cholangiocarcinoma cell line, QBC939, inhibited the luciferase reporter activities of wild-type PTEN (P<0.01) and PDCD4 (P<0.05) and had no this effect on mutated PTEN and PDCD4. Moreover, loss of microRNA-21 function led to a significant increase of PTEN and PDCD4 protein levels in QBC939 cells. Elevated microRNA-21 levels were accompanied by marked reductions of PTEN and PDCD4 expression in the same cholangiocarcinoma tissue.</p><p><b>CONCLUSION</b>microRNA-21 expression is up-regulated in human cholangiocarcinoma and PTEN, PDCD4 are direct effectors of microRNA-21.</p>

Bio panning of human stem cell factor(2) mimetic peptides from phage displayed random peptide library / 中国医学科学院学报

<p><b>OBJECTIVE</b>To screen human stem cell factor (hSCF) mimetic peptides in vitro with a phage-display random peptide library.</p><p><b>METHODS</b>Phage clones with high hSCF receptor (rc-kit/Ig 1-3)-binding activity was screened from phage-displayed random hepta/dodecapeptide library by phage enzyme-linked immunosorbent assay (ELISA). Phage single DNA was extracted and sequenced. Four kinds of peptide with higher c-Kit/Ig 1-3 binding activity were chosen for synthesis and characterized by using cell proliferation assay with 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) method in UT-7 cells.</p><p><b>RESULTS</b>Eleven Ph.D.-C7C clones and eight Ph.D-12 phage clones with high hSCF receptor-binding activity were selected from phage-displayed random hepta/dodecapeptide library, respectively. Sequence analysis showed there were no homologous sequence between hSCF and these screened mimetic peptides except one homologous sequence DPSPHTH found in heptapeptide library. All these four synthesized peptides (CE3, CE16, LE4, and LE20), particularly CE16 and LE20, stimulated UT-7 cell proliferation.</p><p><b>CONCLUSION</b>Four hSCF mimetic peptides were successfully isolated from phage-displayed random peptide library..</p>

Expression, purification, and characterization of the first three immunoglobulin-like domains of human stem cell factor receptor / 中国医学科学院学报

<p><b>OBJECTIVE</b>To express the first three immunoglobulin-like domains of human stem cell factor receptor (c-Kit/Ig1-3) in E. coli and HEK293 ET cells and study their binding activity for stem cell factor (SCF).</p><p><b>METHODS</b>In prokaryotic expression system, a double mutant form of c-Kit /Ig1-3 (c-Kit /Ig1-3(DM) was produced by overlap PCR and cloned into pET16b. The recombinant protein was expressed in E. coli BL21 (DE3) and refolded by dilution. In eukaryotic expression system, the gene of c-Kit/Igl13 with eight histidine segments was cloned into pEAK12 and the recombinant plasmid was transfected into HEK293 ET cells. The fusion protein was harvested from the growth medium and purified on Ni-NTA agarose column. The recombinant protein was tested for the receptor binding activity with his-tag pull-down and enzyme-linked immunosorbent binding assay.</p><p><b>RESULTS</b>In E. coli c-Kit /Ig1-3(DM) as produced as an inclusion body and showed low binding activity for SCF after refolding. Two HEK293 ET cell clones that express high levels of c-Kit/Ig1-3 were produced and each clone secreted 2p micro/ml of recombinant protein, whose relative molecular mass was about 58,000. Eukaryotically expressed c-Kit/Ig1-3 had specific binding activity for SCF, and the dissociation constant (Kd) was 9.39 nmol/L.</p><p><b>CONCLUSION</b>c-Kit/Ig1-3 with high receptor binding activity is successfully produced in HEK293 ET cells.</p>

Expression of human HSF in E. coli and its effects on mobilization of hematopoietic stem cells in rhesus monkeys / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the expression of hHSF in E. coli and its effect on the mobilization of hematopoietic stem/progenitor cells.</p><p><b>METHODS</b>The hHSF gene was obtained by overlapping PCR and cloned into the vector pET30a to yield pET30a-hHSF, which was transformed into E. coli BL21(DE3) and expressed with IPTG induction. Subsequently, rhHSF was purified by gel filtration and cation exchange chromatography and subjected to refolding. Molecular weight of hHSF was measured by MALDI-TOF Mass Spectroscopy. The N terminal amino acid sequence rhHSF was determined by protein sequencing. rhHSF was profiled in rhesus monkey for mobilization of peripheral blood stem cells. Eight rhesus monkeys were equally divided into two groups. The first group was administered single subcutaneous injection of 500 microg/kg hHSF, while the other one was administered 10 microg.kg(-1).d(-1) G-CSF for 4 days followed by a single subcutaneous injection of 500 microg/kg rhHSF.</p><p><b>RESULTS</b>The sequence coding hHSF was confirmed by sequencing and the induced-expression level was about 30% of total cell proteins. The purity of target protein was over 95%. The sequence of N terminal 10 amino acids and the amino acid composition were consistent with the theoretical parameters; molecular weight of rhHSF was 7540. The peripheral CD34(+) cells, CFU-GM yields, and neutrophils peaked at 3 h (16.3-folds increase compared with baseline), 1 h (1.9-folds increase) and 45 min (4.4-folds increase) respectively after the single injection of rhHSF. The addition of rhHSF after the last dose of G-CSF boosted these levels to 25.8-folds, 8.7-folds and 8.3-folds respectively.</p><p><b>CONCLUSION</b>hHSF is highly expressed in E. coli and rapidly mobilizes the hematopoietic stem/progenitor cells and neutrophils in rhesus monkeys. hHSF shows distinct synergistic effect with G-CSF.</p>

The effects of rhG-CSF and rhSCF on peripheral blood leukocytes and CFU-GM in rhesus monkeys / 中国实验血液学杂志

To evaluate the effects of rhG-CSF and rhSCF on mobilization of the peripheral blood stem cells, 15 monkeys were divided into control, rhG-CSF 10 micro g/(kg x day) and rhG-CSF 10 micro g/(kg x day) + rhSCF 50 micro g/(kg x day) treated groups. Monkeys were administered with vehicle, rhG-CSF and rhG-CSF + rhSCF subcutaneously once daily for 14 days, respectively. The results showed that the highest counts of leukocyte of rhG-CSF treated group were 411% of baseline value on day 7 after administration, compared with that of rhG-CSF + rhSCF treated group which were 538% on day 9. The highest counts of leukocytes lasted for 3 days in combined treated group. CFU-GM from peripheral blood in the two groups were 8.37 and 11.75 times higher at 5 and 9 days respectively after the mobilization. It is concluded that rhG-CSF significantly increases the number of peripheral blood leukocytes and CFU-GM, and a better effect can be obtained by rhSCF + rhG-CSF combined administration.

Gene therapy of rat prolactinomas mediated by adenoviral vectors with rat tyrosine hydroxylase gene / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the potential of gene therapy of rat prolactinomas mediated by adenoviral vectors with a gene encoding rat tyrosine hydroxylase.</p><p><b>METHODS</b>Recombinant replication-deficient adenovirus named Ad-GFP-TH with rat TH-cDNA and control adenovirus named Ad-GFP were constructed by homologous recombination in bacterial cells. The rat pituitary prolactinoma cell line MMQ are chosen as the target cells to study the effect of gene therapy on their growth and prolactin secretion mediated by Ad-GFP-TH.</p><p><b>RESULTS</b>Recombinant Ad-GFP-TH and Ad-GFP were successfully reconstructed. Transfection of MMQ cells with Ad-GFP-TH not only restrained their growth but also decreased their PRL secretion.</p><p><b>CONCLUSION</b>Gene therapy may serve for a potential treatment for prolactinomas, especially invasive prolactinomas.</p>

The transcriptional regulation study on human delta globin gene with CAAT box C-->T point mutation in its promoter / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the transcriptional regulation of human delta globin gene with C-->T point mutation at -64 in its promoter.</p><p><b>METHODS</b>Human delta globin genes including wild CAAT box and mutant CAAT box (-64C-->T) were separately cloned into eukaryotic expression vector pcDNA3.1 (-)/Myc-His A which was cut out the strong promoter CMV, transfected MEL cells, and induced by DMSO to express. The transcriptional regulation of human delta globin gene was analysed using semi-quantitative RT-PCR.</p><p><b>RESULTS</b>The expression level of human delta globin gene with mutant CAAT box was 2.2-fold as high as that with wild CAAT box.</p><p><b>CONCLUSION</b>The defective CAAT box of human delta globin gene promoter region may be one of the major reasons for its low expression level.</p>