Search

To investigate the cytotoxic effect and its mechanism of the micromolecule compound on the leukemia cells.The cytotoxic effects of 28 Nilotinib derivatives on K562, KA, KG, HA and 32D cell lines were detected by MTT assays, and the compound Nilo 22 was screen out. Cell apoptosis and cell cycle on leukemia cells were detected by flow cytometry. The effect of compound screened out on leukemogenesis potential of MLL-AF9 leukemia mice GFPNilo 22 serves as the most outstanding candidate out of 28 Nilotinib derivatives, which impairs leukemia cell lines, but spares normal hematopoietic cell line. Comparing with Nilotinib, Nilo 22 could induce the apoptosis of GFPNilo 22 shows a significant cytotoxic effect on mice and human leukemia cells, especially for drug resistance cells. Nilo 22 is a promising anti-leukemia agent to solve the common clinical problems of drug resistance and relapse of leukemia.探究新型端粒酶抑制剂Nilo 22对白血病细胞的杀伤作用与机制.探讨一系列人工合成的小分子化合物对白血病细胞的杀伤作用及其作用机制.采用MTT法检测28个小分子化合物对K562、KA、KG、HA及32D细胞系的杀伤作用，筛选出安全有效的化合物Nilo 22。采用流式细胞术检测该化合物对MLL-AF9小鼠白血病细胞（GFP筛选到能有效杀伤白血病细胞系且对32D细胞系相对安全的小分子化合物Nilo 22；相对于尼洛替尼，Nilo 22诱导小鼠白血病细胞凋亡的作用更加显著，轻微地阻滞细胞周期于GNilo 22对白血病细胞有显著的杀伤作用，尤其对耐药细胞有很好的杀伤效果，有望成为治疗白血病的先导化合物以解决目前临床常见的白血病耐药和复发问题.

To investigate the role of NF-κB inhibitor in occurence and development of AML.AML and normal bone marrow samples were collected from 8 AML patients and 8 normal persons. The expression of NF-κB signaling pathway genes was detected by NF-κB PCR array. Then, AML mouse model was constructed to test the role of NF-κB inhibitor in AML.The NF-κB signal pathway was activated in AML patients. The up-regulated genes, EDARADD, TNFSF14, could activate the NF-κB signal pathway, IL6 could regulate the inflammatory signal. The down-regulated genes, TNFRSF 10B, TNFRSF1A, could lead to cell apoptosis. the AML mouse model was constructed successfully. Then administration of NF-κB inhibitor reduced the inhibition of leukemia niche to the normal hematopoietic stem cells (HSCs), promoted the HSC to enter into cell cycle.The NF-κB signal pathway is activated in AML cells. AML mouse model is constructed successfully. NF-κB inhibitor has a potential to treat AML and promotes the HSC to enrter into cell cycle.

To investigate the effect of ADAR1 on the occurrence and development of mouse T cell acute lymphoblastic leukemia (T-ALL).Lck-Cre; ADAR1lox/lox mice were generated through interbreeding. The lineage-cells of Lck-Cre; ADAR1lox/lox mice and the control were enriched respectively by the means of MACS, and the lin- cells were transfected with retrovirus carrying MSCV-ICN1-IRES-GFP fusion gene. Then the transfection efficiency was detected by the means of FACS, and the same number of GFP+ cells were transplanted into lethally irradiated recipient mice to observe the survival of mice in 2 recipient group after transplantation.T cell-specific knockout ADAR1 mice were generated, and Notch1-induced T-ALL mouse model was established successfully. The leukemia with T-ALL characteristics occured in the mice of control group, but did not in the ADAR1 kmockout mice after transplantation.ADAR1 plays a key role in the incidence and development of Notch1-induced T-ALL.

To explore an efficient, stable system and method to verify the regulation effect of small molecule compounds on human hematopoietic stem cells (hHSC).By using combination of flow cytometry with study results of surface markers on hHSC, and optimation of sorting process for further studying the effect of small molecular compounds on stem property of hHSC, the single hHSC was treated with published small molecular compounds such as SR1 and UM171 which possess the expansion effect. After treating with hHSC for 14 d, the flow cytometric analysis of cell phenotypes and cell morphologic observation were performed, at the same time the hematopoietic function of cultured hHSC was verified by colony-forming cell (CFC) test and cobblestone area forming cell (CAFC) test.The effects of SR1 and UM171 and their compositions in multi-cell culture were consistent with the published data, therefore the useful concentration of compounds were obtained. The results of multiparameter sorting of single cell (CD34+ CD38- CD45RA- CD90+ CD49f+) and ex vivo culture were consistent with the results of bulk cell culture. The results of cell phenotype analysis was in accordance with flow cytometric results. In addition, CFC test and CAFC test revealed that the colony-forming ability in treated group was significantly higher than that in control group (P0.05).The rapid, efficient stably amplified and short-time culture system for single hHSC and method for varifying the effect of small molecular compounds are established, which provides platform for screening small molecular compounds and lays the foundation for further study of hHSC expansion.

To investigate the growth inhibitory effect of Imatinib derivative TEB-415 on various multiple myeloma (MM) cell lines, such as U226, H929, RPMI8226, MM1R and MM1S.TEB-415, a derivative of Imatinib was synthesized by modifying the chemical structure of Imatinib. MM cell lines (U226, H929, RPMI8226, MM1R and MM1S) were treated with TEB-415, Imatini and Bortezomib of various concentrations. Cells were grown for 72 hours and the growth rate was measured by CCK-8 method, cell morphology was observed and the IC50 was calculated.TEB-415 could inhibit H929 and RPMI8226 growth significantly. When the concentration of TEB-415 was0.1 nmol/L,50% H929 cells died. The IC50 of Imatinib was 0.123 mol/L while the IC50 of Bortezomib was 0.03 nmol/L. In RPMI8226 cell line, when the concentration of TEB-415 was 11.9 mol/L, more than 50% of cells died. In contrast, when RPMI8266 were treated with Imatinib of the concentration of 12.8 mol/L, cells grew normally.In comparison to Imatinib, TEB-415, a derivative of Imatinib, can kill H929 MM cells much effectively, its effecacy is only inferior to Bortezomib. RPMI8226, an MM cell line is insensitive to Imatinib, but still sensitive to TEB-415 and its growth can be inhibited by TEB-415.

Hematopoietic stem cells are capable of self-renewal or differentiation when they divide. Three types of cell divisions exist. A dividing stem cell may generate 2 new stem cells (symmetrical renewal division), or 2 differentiating cells (symmetrical differentiation division), or 1 cell of each type (asymmetrical division). This study was aimed to explore an efficient and stable method to distinguish the way of cell division in hematopoietic stem cells. Previous studies showed that the distribution of Numb in a cell could be used to distinguish the type of cell division in various kinds of cells. Therefore, the distribution of Numb protein was detected by immunofluorescence in mitotic CD48(-)CD150(+)LSK cells of mice exploring the relationship between Numb protein and centrosomes. Since CD48 positive marks the HSC that have lost the ability to reconstitute the blood system in mice, CD48 marker could be used to distinguish cell fate decision between self-renewal and differentiation as a living marker. In this study, the CD48(-)CD150(+)LSK cells were sorted from bone marrow cells of mice and the cells were directly labeled with Alexa Fluor (AF) 488-conjugated anti-CD48 antibody in living cultures. After 3 days, the percentage of AF488(+) cells was evaluated under microscope and by FACS. Then colony forming cell assay (CFC) was performed and the ability of cell proliferation were compared between AF488(+) and AF488(-) cells. The results showed that Numb could be used to distinguish different cell division types of hematopoietic stem cells, which was symmetrically or asymmetrically segregated in mitotic CD48(-)CD150(+)LSK cells. The self-labeled fluorochrome could be detected both by FACS as well as microscope. There were about 40% AF488(+) cells after 3 day-cultures in medium titrated with self-labeled AF 488-conjugated anti-CD48 antibody, and the results were consistent between confocal fluorescence microscopy and flow cytometry analysis. The colony forming ability of AF488(+) cells was significantly higher than that of AF488(-) cells (P0.05). The proliferation ability of AF488(-) cells was also significantly higher than AF488(+) cells (P0.05). It is concluded that the expression of CD48 can distinguish cell division of hematopoietic stem cells and can be used as a live marker for the loss of stemness. In comparison with the Numb protein staining, this method can be used in living cells, thus provides greater convenience for subsequent cell culture studies and cell transplantation experiments.

This study was aimed to investigate the effect of SNS-032 (C17 H24 N4O2S2) on cell cycle, apoptosis, differentiation and self-renewal of hematopoietic stem cells (HSC) in mice. The self-renewal capability of bone marrow cells was measured by cobblestone forming cell test. The expressions of self-renewal regulation genes, cell cycle-related genes, apoptosis-related genes were measured by real-time PCR. The cell cycle status and apoptosis of HSC and HPC were detected by flow cytometry. The results showed that there was no significant difference of the frequency of HSC between SNS-032 and control group. The expressions of CDK1, CDK2, CDK7 and p27 decreased in HSC (P0.05) while the expressions of CDK4, CDK6, p21, p18, p19, Bcl-2, Bax, Puma, p53, Bim1, Sall4 and Notch1 showed no difference between SNS-032 group and control group (P0.05). The fraction of viable HSC in each phase of cell cycle remained unchanged after the treatment of SNS-032 (P0.05). Furthermore, there was no statistical difference in the apoptotic fractions between control and drug-treated groups (P0.05). It is concluded that SNS-032 induce apoptosis of cancer cells. Interestingly, SNS-032 has no significant inhibitory effect on self-renewal and differentiation of normal HSC, as well as no obvious effect inducing apoptosis of normal HSC and HPC.

This study was aimed to investigate the growth and multiple differentiation potential of human umbilical cord tissue derived mesenchymal stem cells (UC-MSCs) transfected by a retroviral vector with catalase (CAT) gene. The UC-MSCs cultured in vitro were transfected by using pMSCV carrying GFP (pMSCV-GFP) and pMSCV carrying CAT (pMSCV-GFP-CAT) respectively, then the MSC-GFP cell line and MSC-GFP-CAT cell line were obtained by sorting of flow cytometry. The GFP expression was observed by a fluorescent microscopy at 48 hours after CAT gene transfection. The GFP+ cells were sorted by flow cytometry. The activity of CAT in GFP+ cells was detected by catalase assay kit. The proliferative capacity of transfected UC-MSCs was determined by cell counting kit-8. The differentiation ability of gene-transfected GFP+ cells into osteogenesis and adipogenesis was observed by von Kossa and oil red O staining. The results indicated that green fluorescence in UC-MSCs was observed at 48 hours after transfection, and the fluorescence gradually enhanced to a steady level on day 3. The percentage of MSCs-GFP was (25.54+/-8.65)%, while the percentage of MSCs-GFP-CAT was (35.4+/-18.57)%. The activity of catalase in UC-MSCs, MSCs-GFP, MSCs-GFP-CAT cells were 19.5, 20.3, 67.2 U, respectively. The transfected MSCs-GFP-CAT could be induced into osteoblasts and adipocytes. After 21 days, von Kossa staining showed induced osteoblasts. Many lipid droplets with high refractivity occurred in cytoplasm of the transfected UC-MSCs, and showed red fat granules in oil red O staining cells. There were no significant differences between transfected and non-transfected UC-MSCs cells (p0.05). It is concluded that UC-MSCs are successfully transfected by retrovirus carrying GFP or CAT gene, the activity of catalase increased by 3.4-fold. The transfected UC-MSCs maintain proliferation potential and ability of differentiation into osteoblasts and adipocytes.

To investigate the role of Ara-C in regulating anti-CD3/anti-Pgp mediating T-lymphocytes activities against multi-drug resistant leukemia cells.The diabody of anti-CD3/anti-Pgp was purified by E-tag affinity chromatography. K562 and K562/A02 cells were treated with Ara-C. The expressions of B7-1 and B7-2 on K562 and K562/AO2 cells were detected by FACS. The cytotoxicity of T-lymphocytes combined with anti-CD3/anU-Pgp plus Ara-C was analyzed by CytoTox 96 nonradioactive method.The expressions of B7-1 and B7-2 on K562 and K562/A02 cells treated by Ara-C was significantly higher than those untreated. The effect/target ratio was from 0.39:1 to 25:1, and the killing rate of activated T cells to anti-drug-resistant leukemia cells was from (16.44 +/- 1.20)% to (60.49 +/- 2.90)%. The killing rates were increased gradually, with both the effect/target ratio and the antibody concentration increasing (P0.05).Ara-C may be an important adjuvant for improving anti-CD3/anti-Pgp mediating T-lymphocytes activities against multi-drug resistant leukemia cells.

To prepare monoclonal antibody (McAb) against anti-CD3 ScFv for purifying and detecting serum anti-CD3 antibody concentration.McAb against anti-CD3 ScFv was prepared by hybridoma technique and used to prepare affinity chromatography column, which was used to purify anti-CD3 ScFv and Diabody [CD3 x Pgp] without E-tag. The binding activities of anti-CD3 ScFv, Diabody [CD3 x Pgp] without E-tag, and Diabody [CD3 x Pgp] purified by anti-CD3 affinity chromatography column or anti-E-tag affinity chromatography column against K562/A02 cell and Jurket cells were detected by fluorescence activated cell sorting (FACS) method. ELISA was used to identify the specificity of the McAb.McAb against anti-CD3 ScFv specifically detected serum anti-CD3 ScFv without reacting with sera. The anti-CD3 ScFv purified by anti-CD3 affinity chromatography column and purified by anti-E-tag affinity chromatography column had the same specific binding activity with Jurkat cells. The positive binding rates of Diabody [CD3 x Pgp] without E-tag to K562/A02 and Jurkat cells were 89.87% and 83.95%, respectively. In the competitive binding experiments with K562/A02 and Jurkat cells, the binding rates of Diabody [CD3 x Pgp] without E-tag decreased to 56.30% and 43.78%, respectively.The McAb against anti-CD3 ScFv prepared in our lab can be used to purify and detect serum anti-CD3 antibody concentration.

To observe the effects of Ara-c on the expression of CD86 molecule on acute leukemia cells and explore the possible mechanisms.The expression of CD86 on U937, HL-60 and NB4 cell lines treated with or without Ara-C wa assayed by flow cytometry. The mRNA expression of CD86, NF-kappaB, IFN-gamma was examined by semiquantitative RT-PCR.UP-regulation of CD86 was observed on those cells treated by Ara-c. The level of CD86 and NF-kappaB mRNA in Ara-c treated cells was significantly enhanced. IFN-gamma was detectable 72 hours after T cell activation.Ara-C can enhance CD86 and NF-kappaB expression on acute leukemia cells, which may play critical role in T cell activation and differentiation.

To construct and express a diabody [CD3 x Pgp] without Etag and analyse its biological activity.In this study, the diabody [CD3 x Pgp] was obtained by PCR and restriction cleavage, and expressed in E.coli 16C9. The product was purified by anti-anti-CD3 scFv affinity chromatography and verified through SDS-PAGE electrophoresis. Flow cytometry(FCM) was used to analyse the bingding properties and competitive bingding capacity.The sequence of diabody [CD3 x Pgp] without Etag was correct. It migrated as two bands with the expected molecular weight(25 kD and 26 kD) in SDS-PAGE. The binding rate to CD3 and Pgp antigen was 83.95% and 89.87% respectively. The competitive bingding rate to CD3 and Pgp was 43.78% and 50.25% respectively.The diabody [CD3 x Pgp] without Etag has been successfully constructed, expressed and purified. The product can bind to CD3 and Pgp antigen specifically, and its biological activity doesn't decrease.

To explore the design and activity determination of small molecular inhibitors of integrin alphavbeta3 through structure-based virtual screening.Based on the crystal structure of integrin ctv33 extracellular segment in complex with an ARG-GLY-ASP ligand, docking procedure against the receptor binding domain was performed on 3D database. Integrin alphavbeta3-mediated cell adhesion assay was performed to assess the adhesion-inhibiting ability of the candidate compounds. Cell migration assay and capillary-structure-like formation inhibition assay were used to estimate the effects of the compounds on integrin alphavbeta3. Analysis of molecular graphics was carried out to deduce a probable binding model of compound with integrin alphavbeta3.From the top 1000 compounds with the best DOCK energy score, 50 compounds were selected for biological assay based on chemical and drug-like diversity. Seven of 50 compounds showed notable inhibition activity on cell adhesion, and two with half-maximum inhibition concentration (IC50) values less than 100 mol/L. The compound with best activity (1-37) showed high inhibitory activity in cell migration assay and capillary-structure-like formation inhibition assay. Molecular graphics analysis indicated that metal ion-dependent adhesion site (MIDAS) might be involved in the compound 1-37-mediated inhibition of ligand binding with integrin alphavbeta3.Through virtual screening combined with biological assay, a promising lead compound was discovered to inhibit integrin alphavbeta3, which embodies the rational drug design with computation aid and brings a new thought and approach to find novel inhibitors of integrin.

To study the specific cytotoxicity mediated by anti-P-gp/anti-CD(3) diabodies in multidrug resistant solid tumor using P-gp as target.The anti-P-gp/anti-CD(3) diabodies were secreted from E. coli strain 16C9 containing the expression plasmid PAYZDCP, grown at 30 degrees C in a shaker flask; the diabodies were purified by affinity chromatography and identified by SDS-PAGE; the effect of the anti-P-gp/anti-CD(3) diabody mediated lysis of P-gp-expressing tumor cells was assayed by (51)Cr release assay in vitro, and by human KB nude mouse xenograft models in vivo.The diabodies were generated by bacteria as a soluble functional form and purified by one-step affinity chromatography with a yield4 mg/L culture medium. In (51)Cr release assay, the diabodies targeted human activated T cells to lyse P-gp(+)-KB/MDR cells in a dose-dependent manner. It suggested that the diabody was able to induce an efficient lysis of the target cells by human T cells in vitro. When combined with activated human T cells, the diabody significantly inhibited the growth of KB/MDR, but had no effect on KB xenografts.The anti-P-gp/anti-CD(3) bispecific antibody is a potent agent for targeting human T lymphocytes to lyse solid tumor cells overexpressing P-gp in vitro and in vivo.

To study the specific targeting cytotoxicity to drug-resistant leukemia cells mediated by anti-Pgp/anti-CD3 diabody.The diabody was purified by affinity chromatography and identified by SDS-PAGE and FACS. The effect of the anti-Pgp/anti-CD3 diabody mediated lysis of Pgp-expressing tumor cells was assayed by human leukemia nude mice xenograft model in vivo.The diabody was produced in E.coli in a soluble functional form and could bind both Jurkat cells (CD3(+)) and K562/A02 cells (Pgp(+)). The binding rates were 86.25% and 86.26%, respectively. It could inhibit tumor growth by 98.57% and prolonged the survival of mice bearing xenografted K562/A02 cells.The diabody was proved to be a potent agent for mediating T lymphocyte cytotoxicity to lyse Pgp expressing tumor cells in vitro and in vivo.

The use of tumor antigen specific antibodies for the delivery of therapeutic agents offers the possibility of targeting therapy with reduced toxicity to normal tissues compared to conventional treatments. However, several factors restrict the use of anti-PGP monoclonal antibodies(Mabs). First, Pgp is expressed in normal tissues, particularly in epithelial and endothelial cells of the gastrointestinal tract, liver, kidney, blood brain barrier, choroids plexus and other organs. It plays a significant role to transport drugs and toxins in these organs. Therefore, anti-PGP antibodies in combination with cytotoxic compounds or radiolabelled antibodies should neither inhibit the activity of PGP, nor harm the cells which expressed PGP normally. BiMab exploit the specificity of Mab and ensures activation of cellular cytotoxic mechanisms which kill tumor cells only, but not harm normal cells. It will provide a strategy for resistant cancer therapy using anti-PGP antibodies. Second, Repeated administration of murine antibodies generates a strong human anti-mouse immune (HAMA) response in up to 50% of patients after the first dose, and appro ximately 90% following a second treatment. In an effort to reduce the toxicity and antigenicity, we focus to produce anti-PGP antibodies which have the binding activity only, but not inhibit the function of the "pump", and to construct a small and partially humanized recombinant molecule with dual specificity for both PGP and CD3 complex to activate the host immune response toward the tumour. PCR and overlap PCR were used to construct anti-CD3/ anti-Pgp 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, cellular RIA. Plasmid pAYZDCP which expressed the anti-CD3/anti-Pgp Diabody was constructed correctly. The diabody was recovered in high yield( up to 2mg/ L) after E-taq purification and predominantly(90%) as a dimer. The diabody can bind to Jurkat cells (CD3+) and K562/A02 cells(Pgp+). The affinities of the diabody were similar with the anti-CD3 ScFv or anti-Pgp ScFv, respectively. The anti-CD3/ anti-Pgp 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 K562/A02 cells. Multidrug resistance can be reversed experimentally by a variety of drugs, among which the best known are verapamil and trifluoperazine, which unfortunately are of limited use in practice due to severe collateral cardiac toxicity. Anti-PGP x anti-CD3 diabody will provide another therapeutic strategy against multidrug resistance cancer.

To design and evaluate the small peptide mimetic of anti-P-glycoprotein (P-gp) antibody (PHMA02).From the three dementional structure analysis of computer modeling of PHMA02 CDR loops, a small peptide mimetic was designed and determined by flow cytometry.Anti-P-gp peptide mimetic functionally similar to PHMA02 was developed. The peptide mimetic competitively inhibits PHMA02 binding to P-gp and partially block the P-gp function as a drug efflux pump in K562/A02 cells.Some special conformational properties of CDR loops of antibody might serve as lead structures for develop new biological peptide mimetics. Antibody-structure-based design would develop new drug in the future.