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Objective:To study the therapeutic effect of a novel double-target system,in which human umbilical cord-derived MSCs were used as vehicles to deliver fusion protein scFvCD20:sTRAIL to non-Hodgkin ’ s lymphoma. Methods: The traditional methods in molecular biology were used to construct lentivirus expression vectors pLenR. scFvCD20: sTRAIL and contrast vectors. Human umbilical cord-derived MSCs ( HUMSCs ) were labeled with the copGFP by transducing with pseudo viral particles which had been packaged in 293T cells with four plasmid-lentivirus packaging system. Fusion protein scFvCD20:sTRAIL were secreted from MSC. scFvCD20:sTRAIL after that HUMSCs were infected by pseudo viral particles. CCK8 assay was applied to detect the antigen-restricted cell death induced by scFvCD20:sTRAIL in CD20-positive BJAB and Raji cells as well as CD20-negtive Jurkat cells and human normal peripheral blood mononuclear cells (PBMCs). To evaluate the therapeutic effect of MSC. scFvCD20:sTRAIL in vivo,ge-netically modified HUMSCs were intravenously injected into tumor-bearing mice with BJAB cells. The volume of tumor was measured every three days, and the inhibition ratio of tumor was calculated according to tumor volume. Results: Lentivirus expression vectors pLenR. scFvCD20:sTRAIL, pLenR. ISZ:sTRAIL, pLenR. scFvCD20 and pLenR. CopGFP were successfully constructed and these constructs could be expressed stably in HUMSCs by lentivirus transduction. scFvCD20:sTRAIL fusion protein produced a potent inhibition of cell proliferation in CD20-positive BJAB cells,moderate inhibition of the growth of Raji cells,and weak inhibition in CD20-negtive Jurkat cells when compared with ISZ-sTRAIL treatment,and it had no effect on normal human peripheral blood mononuclear cells (PBMCs). The MSC. scFvCD20:sTRAIL treatment significantly inhibited the tumor growth when compared with those treated with MSC. ISZ-sTRAIL. Conclusion: A double-target therapeutic system is well established, in which HUMSCs migrated to tumor site, secreted a novel fusion protein scFvCD20:sTRAIL,and thus locally concentrated scFvCD20:sTRAIL extended antigen-restricted anti-tumor activity. The engineered HUMSCs secreting scFvCD20:sTRAIL showed potent effect on inhibiting tumor growth in BJAB lymphoma malignancy,which may play an essential role in the clinical research .
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Aim To investigate the expression of AB-CB5 and MDR1 in the cell line KG1 a and samples from acute myeloid leukemia ( AML) and their effects on multidrug resistance. Methods The expression of ABCB5 and P-gp ( the expressed product of MDR1 ) in KG1 a cells were detected by flow cytometry as well as Western blot analysis; KG1 a cells were transfected with the specific siRNA of ABCB5 using lipo2000 to reduce the expression of ABCB5; intracellular rhoda-mine123 was measured by flow cytometry;cell viability was detected by MTT; the expressions of ABCB5 and MDR1 in samples from AML were detected by real time PCR. Results ABCB5 and P-gp were overexpressed in KG1 a;the specific siRNA of ABCB5 transiently in-hibited the expression of ABCB5 in KG1 a; the siAB-CB5-KG1 a cells increased the intracellular rhodamine 123 and have been more sensitive to adriamycin com-pared with the parent KG1a. ABCB5 gene expression in samples from AML was higher than healthy people. Further, the expression of ABCB5 in 38 relapse or re-fractory AML significantly exceeded the 33 drug sensi-tive. And we found a significant positive correlation between ABCB5 expression and MDR1 gene expression in the 38 patients with relapse or refractory AML. Conclusion ABCB5 , as well as P-gp contributes to mediate multidrug resistance of AML, which provides a novel target for the therapy of relapse or refractory AML.
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Background and purpose:Breast cancer is one of the most common carcinoma among female patients with high mortalities. Drug-resistance is the major reason that leads to chemotherapy failure in clinical practice. MCF-7/ADR is a multi-drug resistant cell line that was established on the basis of breast cancer cell line MCF-7. This research aimed to investigate the anti-apoptotic effect of c-fos in resistant breast cancer cell MCF-7/ADR, and to compare with its sensitive counterpart MCF-7.Methods:Doxorubicin with various concentrations was used to treat MCF-7 as well as its MDR- counterpart MCF-7/ADR. The growth inhibitory rate of MCF-7 and MCF-7/ADR wasdetermined by MTT assay. Additionally, RT-PCR was used to test the expression of P-gp and c-fos mRNA in MCF-7 and MCF-7/ADR; The expression of c-fos mRNA was detected by RT-PCR after 3 μmol doxorubicin treatment;We further established cell lines that stably interfered with c-fos, named MCF-7/ADR/si-fos-8B, MCF-7/ADR/si-fos-3D. Flow cytometry and MTT assay were used to investigate the apoptosis rate and inhibitory rate in these above cells under the treatment of 5-FU, CDDP or γ-radiation. At last, RT-PCR and Western blot analysis were used to detect the expression of bax, bcl-2, puma, p53.Results:The expression of c-fos and P-gp (MDR-1) was up-regulated in MCF-7/ADR, compared with its sensitive counterpart MCF-7. Additionally, the resistant fold of MCF-7/ADR to doxorubicin was nearly 40; The expression of c-fos was gradually up-regulated after 3 μmol doxorubicin treatment; The sensitivity to drugs (5-FU and CDDP) was increased after c-fos interference while the apoptosis rate was also increased after 5-FU, CDDP and γ-radiation treatment. RT-PCR and Western blot analysis indicated that up-regulation ofbax,puma,p53 after c-fos interference while the expression of bcl-2 was down-regulated.Conclusion:c-fos may act as an anti-apoptotic protein in resistant breast cancer cell line MCF-7/ADR by regulating the expression of apoptosis related proteins, and may play a vital role in the formation of multi-drug resistance phenotype.
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Objective:To prepare anti-human c-kit monoclonal antibody(McAb) by genetic immunization in spleen,and to determine practicability of these means to produce McAbs based on the biological activity of anti-human c-kit antibody.Methods:Recombinant plasmid pcDNA3.1/c-kit extracellular domain was constructed by molecular cloning techniques,and was used to immunize BALB/c mice in spleen directly to prepare mAb against human c-kit by routine hybridoma technique.FASC、fluorescence microscope and Western blot were utilized to identify the prepared antibody.Results:c-kit extracellular region was cloned and insert pcDNA3.1 plasmid successfully.Three hybridoma cell lines 6C4、2C5 and 5D5 that secrete anti-human c-kit McAbs were obtained after using intra-spleen immunization with a DNA vaccine.The isotypes of these three antibodies were all IgM,and the epitopes were different with each other.Conclusion:The method of genetic immunization into spleen can be used to prepare anti-human c-kit monoclonal antibodies.