Construction and expression of disulphide stabilized anti-CD3/anti-Pgp diabody / 生物工程学报

We constructed and expressed an anti-CD3/anti-Pgp (P-glycoprotein) diabody previously. However, the two chains of diabody are associated non-covalently, resulting in being capable of dissociating. The aim of this study is to enhance the stability of the diabody. We introduced cysteine residues into the CD3 or Pgp V-domain to covalently lock the two chains together. The disulphide crosslinked diabody were expressed by Escherichia coli (E. coli) 16C9 and purified by a cation exchange column and an anti-Etag affinity chromatography. The purified proteins were verified through SDS-PAGE. Flow cytometry (FCM) was used to analyse the binding properties, competitive binding capacity and stability in vitro. The dsPpg-diabody failed to form disulphide bond properly. The designed disulphide bridge between the different chains of dsCD3-diabody was formed correctly. FCM demonstrated the dsCD3-diabody has specific antigen binding activity, the same binding activity and competitive binding activity as its parent diabody. The dsCD3-diabody retained the full activity even after 72 h incubation at 37 degrees C in human serum, in contrast, the parent diabody began to lose activity after only 1 h and lose all its activity 24 hours later. The induced disulphide bond in the CD3 V-domain effectively enhanced the stability of anti-CD3/anti-Pgp diabody. The method of stabilizing a diabody by introducing a disulphide bond into is practical.

Soluble-expression, purification and activity analysis of extracellular domain III of flt1 / 生物工程学报

To prepare a soluble human extracellular III domain of Flt1 and analyze its biological activity. The gene encoding extracellular domain III of Flt-1 was cloned into the expression vector pAZY by RT-PCR from human umbilical vein endothelial cell (HUVEC), and induced to express in Escherichia coli by low phosphoric medium, the product was purified by E-tag affinity chromatography. SDS-PAGE and Western blotting analysis showed that Flt-1 gene domain III gene was expressed in E. coli and the yield of the soluble fusion protein was about 1.10 mg/L. Enzyme-Linked ImmunoSorbent Assay (ELISA) revealed that the Flt-1 domain III was able to bind to VEGF165 dose-dependently. Monolayer denudation assay and Transwell assay showed that the fusion protein could inhibit HUVECs migration induced by conditional medium with 50 ng/mL VEGF165 and 100 ng/mL bFGF. In conclusion, Flt-1 gene domain III gene has been successfully cloned and expressed in E. coli, which will be useful in both the research on the function of Flt-1 gene domain III and preparation of anti-Flt-1 monoclonal antibody in the future.

Effect of VEGF-C Gene Transfection on the Expression of VEGF-C in Human Cervical Carcinoma HeLa Cells and the Molecular Meehnisms of Its Anti-apoptosis Effect / 中国肿瘤临床

Objective: TO explore the effect of VEGF-C gene transfection on the expression of VEGF-C in human cervical carcinoma HeLa cells and the mechanisms of its anti-apoptosis effect. Methods: The con-structed pcDNA3.1(+)NEGF-C vector was transformed into human cervical cancer HeLa cells and was select-ed by G418. The changes in the expression level of VEGF-C mRNA and protein were determined by semi-quantitive RT-PCR and ELISA. HeLa cells with overexpression of VEGF-C were named as HeLa/S1. The expression level of NF-KB and bcl-2 mRNA was determined by RT-PCR in transfected cells. Results: After transfection by liposome, the VEGF-C mRNA level and the expression of VEGF-C protein in transfected cells were higher than those in the control groups. HeLa/S1 cell line was successfully established. In HeLa/S1 cells, the expression of NF-κB (2.06±0.09 vs 1.35±0.02 vs 1.38±0.02 P<0.05) and bcl-2 gene mRNA (2.02± 0.67 vs 0.41±0.06 vs 0.37±0.06, P<0.05) level were higher than those in the control groups. Conclusion: VEGF-C gene transfection by liposome can increase the expression of VEGF-C in human cervical cancer HeLa cells. NF-κB is stimulated and induces the overexpression of bcl-2 gene in HeLa/S1 cells.

Study on the construction and expression of the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein / 生物工程学报

Several studies have demonstrated the role of 4-1BBL in T cell activation. Furthermore, enhanced 4-1BB/4-1BBL interaction has been shown to amplify T-cell-mediated antitumor immunity in several mouse models. However, when applied in humans, it was difficult to generate sufficient T cells ex vivo and whole cell vaccines to transfer back into patients. To overcome this difficulty, we have focused on producing the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein. In this report, PCR and overlap PCR were used to construct the human 4-1BBL extracellular domain/anti-CD20 Fab' expression vector. DNA sequence was analyzed by the Terminus of Dideoxy Nucleotide. The product was purified by affinity chromatography and analyzed by SDS-PAGE and HPLC; its antigen binding activity was examined by rosetting assay. The data of DNA sequence showed that the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein was corrected. The fusion protein was recovered in high yield (up to 200 microg/mL) after E-taq purification. The fusion protein was capable of simultaneous binding to stimulated Jurkat cells and Raji cells as shown by cellular rosetting. In conclusion, the human 4-1BBL extracellular domain/anti-CD20 Fab' fusion protein was induced to express in E. coli 16C9. The results of some biological activity experiments indicated that the fusion protein could bind to stimulated Jurkat cells and Raji cells. Furthermore, 4-1BBL-negative tumors can be converted into 4-1BBL-positive tumors by the fusion protein without the need for 4-1BBL gene transfer to the malignant cells.

Expression and clinical implications of the soluble drug resistance-related calcium-binding protein (sorcin) gene in leukemia patients / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the relationship between the expression of soluble drug resistance-related calcium-binding protein (sorcin) gene and the clinical multidrug resistance in acute leukemia (AL).</p><p><b>METHODS</b>A semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to investigate the transcription levels of the human sorcin gene in 95 AL patients and 27 controls.</p><p><b>RESULTS</b>Sorcin gene expression was significantly higher in AL patients than in normal contrls (P < 0.001), and higher in relapsed/refractory acute myeloid leukemia (AML) patients than in those newly diagnosed or in complete remission. Sorcin gene overexpression was significantly lower in non-resistant patients than in resistant ones (P < 0.001). CR rates of these two groups were 20.0% and 80.0%, respectively. Sorcin gene expression was higher in AML-M(5) patients than M(2), M(3), M(4) patients.</p><p><b>CONCLUSION</b>Sorcin gene overexpression is significantly associated with clinical multidrug resistance and prognosis, it is one of the indicators for predicting prognosis of AL patients.</p>

Expression and clinical implication of soluble resistance-associated calcium-binding protein gene and multi-drug resistance gene in leukemia / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the relationship between soluble resistance-related calcium-binding protein (sorcin) gene and multidrug resistance gene (mdr1), and their significance in clinical drug resistance and prognosis of acute myeloid leukemia (AML).</p><p><b>METHODS</b>Amplification of sorcin gene and mdr1 gene in K562/A02 cell detected by Northern blot, were monitored by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) in 65 AML patients and 27 normal controls, with their relationship and clinical outcame analyzed.</p><p><b>RESULTS</b>The amplification of sorcin gene and mdr1 gene in AML patients were significantly higher than that in the normal control, which were related to clinical drug resistance and prognosis. The amplification of sorcin gene was related to the amplification of mdr1 gene in the two groups. The clinical drug resistance incidence rate and complete remission rate were 92.9% and 7.1% in sorcin(+)/mdr1(+) group. They were 8.6% and 91.4% in the sorcin(-)/mdr1(-) group (P < 0.001).</p><p><b>CONCLUSION</b>The co-amplification of sorcin and mdr1 gene can be taken as a good indicator of clinical drug resistance and prognosis of AML.</p>

Study on the construction and expression of anti-CD3/anti-CD20 Diabody / 中国免疫学杂志

Objective:To construct and express anti CD3/anti CD20 Diabody and identify its biological activity.Methods:PCR and overlap PCR were used to construct anti CD3/anti CD20 Diabody.DNA sequence was analyzed by the Terminus of Dideoxy Nucleotide.The product was purified by affinity chromatography and analyzed by both the detection of Western blot and size exclusion chromatography;its antigen binding activity was examined by FACS and rosetting assay.Results:The data of DNA sequence showed that the anti CD3/anti CD20 Diabody was corrected.The Diabody was recovered in high yield(up to 1 mg/ml) after E taq purification and predominantly(90%) as a dimer.The Diabody binded Jurkat cells(CD3 +) and Daudi cells (CD20 +),respectively.Furthermore,the Diabody was capable of simultaneous binding to Jurkat cells and Daudi cells as shown by cellular rosetting.Conclusion:The anti CD3/anti CD20 BsF(ab') 2 was first recast into the Diabody format and succeeded to obtain high level expression.The results of some biological activity experiments indicated that the Diabody could bind to Jurkat cells and Daudi cells.

Research of anti-tumor effect of PHⅡ-7 to K562/A02 cells / 中国药理学通报

Aim To study the mechanism of anti-tumor effect of PHⅡ-7 to K562 and K562/A02 cells.Methods The effects of individual and combined doxorubicin on K562 and K562/A02 cells were observed by MTT assay.The coefficient of drug interaction was used to analyse the synergistic effect of PHⅡ-7,obtaining the RNA from the cells stimulated by PHⅡ-7 with different doses to analyse the MDR1 gene expression level.Finally,the cumulation of doxorubicin was observed in K562 and K562/A02 cells after being coped with PHⅡ-7.Results PH Ⅱ-7 had anti-tumor effect with IC50 of (1.37?0.37) ?mol?L-1;(1.48?0.34) ?mol?L-1 for K562 and K562/A02,respectively.It could potentiate the anti-tumor effect of dororubicin with CDI of 0.22 and 0.09 for K562 and K562/A02,respectively.PHⅡ-7 could synergistically inhibit the proliferation of K562 and K562/A02 cells.The decrease of MDR1 expression level depended on the increase of dose of PHⅡ-7 acting on cells.PHⅡ-7 could also develop the cumulation of doxorubicin in cells.Conclusion PHⅡ-7 is not only a Cytotoxinic drug but also can synergistically inhibit the proliferation of K562 and K562/A02 cells with the decrease of MDR1 expression level,especially in K562/A02 cells.

The metastasis suppressing ability and its mechanism of calmodulin antagonist EBB in human metastatic ovarian clear cell line ES-2 / 中国药理学通报

Aim To investigate the potential suppressing effect of calmodulin antagonist EBB on metastasis-associated properties of human metastatic ovarian clear cell adenocarcinoma cell ES-2.Methods MTT assay was used to assess the growth inhibition of EBB on ES-2 cells.The invasive capacity and motility potential were determined by Transwell chamber assay and Wound assay.[Ca2+]i was observed under the laser scanning confocal microscopy.Results EBB inhibited the proliferation of ES-2 cells in vitro.The IC50 on ES-2 cells was(13.67?1.56)?mol?L-1.The invasive ability and motility potential of ES-2 cells were decreased after exposure to 3,7 and 14 ?mol?L-1 EBB respectively(P