Relationship between miR-218 and CDK6 expression and their biological impact on glioma cell proliferation and apoptosis / 中华病理学杂志

<p><b>OBJECTIVES</b>To investigate the relationship between the expression of miR-218 and CDK6 in glioma cells, and their biological impacts on the tumor cell proliferation and apoptosis.</p><p><b>METHODS</b>Expression levels of miR-218 as well as CDK6 and Ki-67 proteins were analyzed in 60 cases of gliomas with various grades and 10 control brain tissue samples by tissue microarray, locked oligonucleotide probe in situ hybridization and immunohistochemistry. Glioblastoma multiform cell line (U87MG) was transfected with miR-218 mimics (mimics group) and a control sequence (control group), followed by qRT-PCR detection of miR-218 and immunocytochemical stain of CDK6 and Ki-67, respectively. Single cell gel electrophoresis was used to detect the presence of apoptotic cell.</p><p><b>RESULTS</b>The miR-218 labeling indexes (LI) were statistically different (P<0.05) among all groups including control (22.45 +/- 0.59) and various glioma groups (grades I - II 4.00 +/- 1.07, grade III 1.87 +/- 1.06 and grade IV 0.94 +/- 0.78, respectively). The CDK6 LI of the four groups was 7.25 +/- 1.20, 16.71 +/- 0.80, 24.43 +/- 0.62 and 32.05 +/- 0.43, respectively. Significant differences existed between the control group and the glioma groups, and between grade IV and grades I - II glioma groups (P<0.01). Ki-67 positive cell densities of the above four groups (0.00 +/- 0.00, 9.30 +/- 3.48, 31.15 +/- 9.44 and 60.15 +/- 13.60) were significantly different from one and another (P<0.01). The expression of miR-218 negatively correlated with CDK-6 LI (r = -0.480, P<0. 01) and Ki-67 positive cell density (r = - 0.534, P<0.01), while the latter two positively correlated with each other (r = 0.530, P<0.01). U87MG transfection experiment showed that the miR-218 level of the mimics group was significantly higher than that of the control group (P<0.01). CDK6 and Ki-67 LI of the mimics group (14.74 +/- 1.19 and 30.88 +/- 3.31) were significantly lower than those of the control group (79.06 +/- 2.07 and 64.94 +/- 3.96, P<0.01), whilst its apoptotic index (AI) (68.44 +/- 7.05) was significantly higher than that of the control group (13.04 +/- 0.97, P<0.01).</p><p><b>CONCLUSIONS</b>The expression level of miR-218 is an important reference indicator for the assessment of the grade of gliomas. An aberrant decrease of its expression may lead to an increase of the CDK6 expression and proliferative activity of giloma cells. Introducing exogenous miR-218 may effectively down-regulate the CDK6 expression, inhibit cell proliferation and induce apoptosis of malignant giloma cells. These findings imply that miR-218 may serve as a therapeutic agent against malignant glioma.</p>

Enhanced expression of human vimentin intermediate filaments in hepatocellular carcinoma cells decreases their proliferative and invasive abilities in vitro / 中华肿瘤杂志

<p><b>OBJECTIVE</b>Expression of vimentin in carcinoma cells is a marker for poor prognosis in patients. The aim of this investigation was to assess the influence of vimentin on the characteristics of carcinoma cells.</p><p><b>METHODS</b>The full-length vimentin gene open reading frame (1401 base pairs) was cloned into the plasmid vector pcDNA 3.1 (+), and these vectors were used to stably transfect the human hepatocellular carcinoma HepG2 cell line. Vimentin gene expression was evaluated by RT-PCR and Western blot. Proliferative activity and invasive potential of tumor cells were determined by the CellTiter 96 aqueous one solution cell proliferation assay and BioCoat GFR Matrigel invasion chamber, respectively.</p><p><b>RESULTS</b>DNA sequencing and restriction endonuclease digestion analysis demonstrated that the recombinant vector was correctly cloned. The stable cell line demonstrated a higher vimentin RNA and protein expression. However, both proliferative and invasive abilities of the cells were reduced in vitro ( P < 0.05).</p><p><b>CONCLUSION</b>A recombinant plasmid pcDNA3. 1-VIM is successfully constructed and a carcinoma cell line HepG2-pV highly expressing vimentin is obtained. Recombinant vimentin protein suppresses the proliferative and invasive abilities of HepG2 cells, suggesting that it might decrease malignant phenotype of tumor cells in vitro. This work makes a foundation for further study on the relationship between vimentin and biological phenotype of carcinoma cells.</p>

Searching for genes interacting with human PCIA1 gene by using the bacterial two-hybrid system / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To search for the genes which could interact with newly found homo sapiens cross-immune reaction antigen (PCIA1) gene and accordingly to provide insights into the study of the gene function.</p><p><b>METHODS</b>The Stratagene's BacterioMatch Two-Hybrid System and BacterioMatch Fetal Kidney Library were adopted and the recombinant bait plasmid pBT-PCIA1 was cotransformated with the target plasmid pTRG-cDNA library DNA into the reporter stain. After screening and isolation of positive pTRG clones, the target genes were identified by DNA sequencing and bioinformation analysis.</p><p><b>RESULTS</b>Among all the seven detected target genes, three genes' function were not known, the other four genes had important functions. Their mutations or abberant expression resulted in severe diseases and overexpression of ACTN4 (actinin, alpha 4), PSAP (prosaposin) or EIF3S10 (eukaryotic translation initiation factor 3, subunit 10 theta) could promote tumor development and progression.</p><p><b>CONCLUSION</b>The bacterial two-hybrid system technique is an efficient method, which can provides insights into the study of novel genes' function by detecting protein-protein interactions. This study indicates that PCIA1 gene expression correlates with tumor formation, invasion and metastasis.</p>

Specific inhibition of Raf-1 gene expression in HNE1 by RNA interference / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To silence the expression of Raf-1 gene in HNE1 cells using vector-based RNA interference (RNAi) technique.</p><p><b>METHODS</b>The vector containing the human U6 promoter was used for targeted gene silencing when a dsDNA oligonucleotide encoding an appropriate shRNA was ligated into the vector, and 67nt oligonucleotide fragment was inserted into the downstream of the U6 promoter. Plasmids containing different Raf-1 target sequences [ (1) pshuttle-Raf-1-a( 225), (2) pshattle-Raf-1-b ( 358) and (3) pshuttle-Raf-1-c(474)], were transfected into HNE1 cells. Expression of Raf-1 mRNA was assayed by RT-PCR. Apoptosis were determined by cytometry.</p><p><b>RESULTS</b>Vector-based RNAi had advantages over antisense RNA because it could be delivered to the target cell more efficiently, and effect could last longer. Raf-1 expression could be inhibited by plasmid-expressed shRNA. Three different targeting sequences were selected from Raf-1 gene, and the inhibitory effect of pSIREN shuttle-Raf-1-b (358) was biggest.</p><p><b>CONCLUSION</b>Raf-1 expression in HNE1 cells can be inhibited significantly using plasmid-based RNAi.</p>

Construction of the recombinant adenovirus vector expressing human CD40 ligand gene / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To construct a recombinant adenovirus vector expressing hCD40L gene and explore it in the use of anti-tumor gene therapy.</p><p><b>METHODS</b>1,900 bp gene fragment was obtained form plasmid pORF-hCD40L by Xho I/Swa I cutting and then cloned directionally into the pShuttle plasmid, finally, the resultant plasmid was digested by restriction endonnuclease PmeI and subsequently cotransformtion into BJ5183 cells with the adenoviral backbone pAdEasy-1 to obtain the homologous recombinant and then the recombinant was packaged in the 293 cells. Some methods such as PCR and endonulease digestion were employed to identify the recombinant adenovirus.</p><p><b>RESULTS</b>The evidences of endonulease digestion and PCR analysis confirmed that recombinant hCD40L gene was correctly inserted into adenovirus vector.</p><p><b>CONCLUSION</b>The adenoviral vector which expressed hCD40L gene was constructed. It provides an experimental basis for studies on it expression in the mammalian cells and in tumor gene therapy.</p>

Prokaryotic expression of extracellular ligand binding domains of chick tie-2 and its anti-angiogenesis effect / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the prokaryotic expression of extracellular ligand binding domains of chick tie-2, the purification, refolding conditions of the recombinant protein, and its anti-angiogeneic effect.</p><p><b>METHODS</b>A DNA fragment encoding extracellular ligand binding domains of chick tie-2 was obtained by PCR amplification using a previous constructed plasmid as a template. The amplified fragment was then inserted into prokaryotic expression vector pQE30, and was expressed in E.Coli XL-1 blue by adding isopropyl-beta-D-thiogalactoside(IPTG). The recombinant protein in inclusion bodies was purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography under denatured conditions. Then the refolding of the purified protein was performed with gradient dialysis. The target protein was injected s.c. into mouse, and the antibody was detected by ELISA and Western blot analysis. The antibody was purified from the antiserum and then incubated with human umbilical endothelial vein cell (HUEVC) to find its anti-angiogenesis in vitro by using propidium iodide(PI) dying through FACS. Alginate encapsulated tumor cell assays were performed and micro-vessel density was determined by counting per high power field in the sections stained with an antibody reactive to CD31 to test its inhibition of angiogenesis.</p><p><b>RESULTS</b>The recombinant protein was highly expressed in E.Coli XL-1 blue, and the antibody produced in mouse could specifically recognize the recombinant protein. The purified antibody could induce apoptosis of HUEVC in vitro. The anti-angiogenic effect of the antibody could also be found in alginate-encapsulate tumor cell assay and by counting micro-vessel density.</p><p><b>CONCLUSION</b>The protein of extracellular ligand binding domains of chick tie-2 can be expressed at high level in the prokaryotic expression system, and the expressed protein can induce immune response in mouse. Furthermore, the antibody can induce the anti-angiogenic effect.</p>

Construction of eukaryotic expression plasmid pSecTag2B-msBlyS expressing mouse soluble B lymphocyte stimulator / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study was to clone the soluble form of the mouse BlyS (msBlyS) and insert it into a eukaryotic expression vector pSecTag2B in order to further elucidat the antitumor activity induced by msBlyS expressed by the recombined plasmid pSecTag2B-msBlyS.</p><p><b>METHODS</b>Full length cDNA of mouse soluble BlyS (msBlyS) was amplified by reverse transcription-PCR from total RNA of mouse spleen. The PCR product was ligated directly with linearized vector pCR2.1 supplied in the TA cloning kit. The recombined plasmid pCR2.1-msBlyS which was selected and identified using blue-white screening method and restriction map analysis and the purified original plasmid pSecTag2B were both cut by HindIII and EcoR I. The digested fragments were extracted and purified from low-melting temperature agarose and ligated by T4DNA ligase. The recombined plasmid pSecTag2B-msBlyS were isolated and identified by restricted endonuclease cutting and Sanger dideoxy DNA sequencing.</p><p><b>RESULTS</b>The sequencing data indicated that inserted msBlyS gene had correct DNA sequence and orientation.</p><p><b>CONCLUSION</b>Eukaryotic expression vector pSecTag2B. Expressing mouse BlyS have successfully been cloned. This will provide us an opportunity to do further research work on BlyS.</p>