Improvement and Evaluation on Bisulfite Modification of DNA for DNA Methylation Detection / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To establish a rapid and convenient method of DNA modification by bisulfite sodium for the detection of DNA methylation.</p><p><b>METHODS</b>Through increasing the bisulfite sodium concentration and the temperature of treatment, cutting down the modification time, besides using glassmilk to adsorb the DNA in the purification and recovery, to improve the methods of DNA modification. Efficiency of cytosine converted to thymine in MAGE-A3 gene and DAP-K gene fragments were analyzed by bisulfite sequencing PCR in order to evaluate the DNA modification effect among the improved method, traditional method and kit method.</p><p><b>RESULTS</b>The operating time of test was shortened to about 3 hours by the improved method; conversion rate of unmethylated cytosine to thymine was over 99%; compared with the traditional method and kit method, there was no significant difference (χ(2) = 0.0564, P > 0.05); the improved method was only for the unmethylated cytosine conversion modification, and there was no significant difference in process of methylated cytosine converted to thymine comparing with the traditional method (χ(2) = 0.0149, P > 0.05).</p><p><b>CONCLUSION</b>The improved method has high efficiency of DNA modification and has no significant effect on excessive modification;meanwhile, it has many advantages such as time-saving and easy to operate etc.</p>

Value of DAPK Gene Methylation Patterns in the Diagnosis of Leukemia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To screen the differential methylation patterns of tumor suppressor gene DAPK and evaluate its value as a biomarker for the diagnosis of leukemia.</p><p><b>METHODS</b>The methylation status of DAPK gene promoter's CpG island was analyzed in the genomes of normal human white blood cells and HL-60, U937 and Jurkat cell lines by bisulfite sequencing PCR (BSP). The effectiveness of differential methylation patterns of DAPK gene for diagnosis of leukemia was verified in the leukemia cell lines and peripheral blood samples by methylation specific PCR (MSP).</p><p><b>RESULTS</b>The methylation pattern of DAPK gene in different cell genomes displayed that the degree of unmethylation in normal cell genome was higher than that of leukemia cell lines. The differential CpG sites were found and could be used to differentiate HL-60 and the other 3 cell lines by MSP. Meanwhile, the differential methylation patterns in clinical specimens could distinguish acute non-lymphocytic leukemia (ANLL) and other types of leukemia by MSP. The diagnostic sensitivity, specificity and accuracy were 59.1%, 100% and 82.7% respectively. No relationship was found between MSP diagnosis results and clinical pathological typing.</p><p><b>CONCLUSION</b>The differential methylation patterns of DAPK gene as potential tumor biomarker for diagnosis of leukemia can enrich the means of diagnosis of leukemia, provide idea and basis for finding all kinds of tumor's DNA methylation biomarkers in the future.</p>

Effect of Twist gene on the migration and invasion of gastric carcinoma cells / 中南大学学报(医学版)

OBJECTIVE@#To explore the effect of Twist gene on the migration and invasion of human gastric carcinoma cells.@*METHODS@#MKN28 cells, a human gastric carcinoma cell line, were transfected with PcDNA3.1-Twist plasmid by lipofectamine transfecting technique. The transfected cells were selected with geneticin. Expressions of Twist,ecadherin and vimentin protein were detected by Western blot in cells transfected Twist gene. Matrigel invision chambers were performed to analyse the cell migration and invasion.@*RESULTS@#MKN28 cells transfected with PcDNA3.1-Twist plasmid showed stronger intracellular expression of Twist protein than MKN28 cells transfected with PcDNA3.1 and MKN28 cells without transfection. The expression of ecadherin protein in MKN28 cells transfected with PcDNA3.1-Twist plasmid was significantly decreased compared with that in MKN28 cells transfected with PcDNA3.1 and MKN28 cells without the transfection. However, The expression of vimentin protein in MKN28 cells transfected with PcDNA3.1-Twist plasmid was significantly increased compared with that in MKN28 cells transfected with PcDNA3.1 and MKN28 cells without transfection. The migration and invasion ability of Twist+ - MKN28 cells were stronger than that of MKN28 cells transfected with PcDNA3.1 and MKN28 cells without transfection.@*CONCLUSION@#Twist gene may promote the migration and invasion ability of gastric carcinoma cells through epithelial mesenchymal transition.

Effect of EphA2 protein on the expression of VEGF and MMP9 proteins in HCT116 cells / 中南大学学报(医学版)

OBJECTIVE@#To determine the effect of EphA2 protein on the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP9) proteins in HCT116 cells.@*METHODS@#High expression of EphA2 protein in HCT116 cells was confirmed by Western blot. HCT116 cells were transfected with EphA2 antisense oligonucleotide. The expression of the transfection efficiency was analyzed by Western blot. VEGF proteins in the cell supernatants were detected by enzyme linked immunosorbent assay(ELISA), and the expressions of MMP9 in cell supernatants were examined by gelatin zymography.@*RESULTS@#EphA2 antisense oligonucleotide suppressed the expression of VEGF and MMP9 proteins in HCT116 cells.@*CONCLUSION@#EphA2 could decrease the invasion and metastasis of HCT116 cells by suppressing the expression of VEGF and MMP9.

SHP-1 gene's methylation status of Daudi lymphoma cell and the demethylation effect of 5-aza-2'-deoxycytidine / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the transcription regulation of 5-aza-2'-deoxycytidine(5-Aza-CdR) on SHP-1 gene and its effects on Daudi cell line growth.</p><p><b>METHODS</b>MTT method and flow cytometry were used to detect the growth and apoptosis of Daudi cells after treated with different dosage of 5-Aza-CdIR. Bisulfite sequencing PCR ( BSP) , T-A cloning and sequence analysis were evaluated for methylation status. The SHP-I mRNA and protein were determined by reverse transcription polymerase chain reaction (RT-PCR) ,immunohistochemistry.</p><p><b>RESULTS</b>(1)After 7 d treatment with 2. 00 micromol/L of 5-Aza-CdR, all cytosines (C) in Daudi cells genome DNA were converted to thymidine, and SHP-1 mRNA and protein expressed again in the cells while those Cs in CpG dinucleotides in untreated Daudi cells remained Cs; (2)5-Aza-CdR inhibited the cell growth,The effects within certain extent were dose and time dependent:after 72 h treatment with 5-Aza-CdR at 200. 00, 20. 00, 2. 00 and 0. 20 micromol/L, the inhibitive rates were 72. 0% , 65. 1%, 51. 5%, 28.8% ,23.4% respectively; (3) 5-Aza-CdR increased apoptosis rate of tumor cells with a dose and times dependent manner within certain extent, too:at the 1,3,5 d treatment with 5-Aza-CdR 2. 00 micromol/L,the apoptosis rates were 2. 3% ,10. 8 % and 17. 1% ; respectively. (4) 5-Aza-CdR also changed cell cycle of tumor cells: at 24 h treatment with 5-Aza-CdR 2.00 micromol/L,92. 7% tumor cells stopped at S phase and G, phase cells were increased gradually with time.</p><p><b>CONCLUSION</b>DNA promoter hypermethylation is associated with SHP-1 gene silence in Daudi lymphoma cell line. 5-Aza-CdR could effectively cause demethylation and inhibit the growth of tumor cell by reactivating the gene transcription.</p>

Growth suppression of colon cancer cells in vitro by DPC4 gene expression and its mechanism / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the effect of DPC4 gene expression on the growth of colon cancer cells and its mechanism.</p><p><b>METHODS</b>Expression plasmid pcDNA3.1-DPC4 was constructed and transfected into the colon cancer cell line SW620 by use of lipofectamine gene transfer technique. DPC4 protein expression was detected by Western blot and immunocytochemistry. The effect of DPC4 gene on the growth of SW620 cells was monitored by population doubling time (PDT) and cloning efficiency. The influence of DPC4 expression on p21WAF1 transcription was investigated by RT-PCR to detect p21WAF1 mRNA.</p><p><b>RESULTS</b>Successful expression of DPC4 protein was detected in the transfected SW620 cells. Compared with the control cells, PDT (74 h) of the DPC4 expressing cells was prolonged and the cloning efficiency (21%) decreased. In addition, the mRNA level of p21(WAF1) in DPC4 transfected cells was increased.</p><p><b>CONCLUSIONS</b>Overexpression of DPC4 gene inhibits the growth of colon cancer in vitro, and induction of p21(WAF1) expression may be an important functional aspect of DPC4.</p>

Effect of matrine on PLA_2 activity of LPS-induced inflammatory rats and its mechanism / 中草药

Object To study the antiinflammatory effect of matrine and its active mechanism. Methods The matrine effects on activities of secretory phospholipase A 2 (sPLA 2) in peripheral serum and cytosolic phospholipase A 2 (cPLA 2) in leucocyte were measured with Escherichia coli membrane incorporated by arachidonic acid as the substrate; the Ca 2+ level of leucocyte was determined using Frua2 AM loading method, and the rat plantar swelling test was used to examine the antiinflammatory effect of matrine. Results One hour after ip 30 mg/mL matrine, the inhibitory rate of sPLA 2 activity was (81.9?1.8)% , cPLA 2 (28.4?6.0) %, while Ca 2+ concentration was (157.10?20.56) nmol/L which was 15.3% higher than that of the control. Plantar swelling test showed that matrine had a significant anti inflammatory effect. Conclusion Matrine is a novel PLA 2 inhibitor with anti inflammatory effect.