Topoisomerase inhibitor upregulates MICA/B expression in breast cancer cells through ATM/ATR and NF-κB pathway / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of chemotherapeutic agents widely used in clinical practice on major histocompatibility complex class I-related chain A and B (MICA/B) expression in breast cancer cells, and to explore the molecular mechanisms involved.@*METHODS@#We examined MICA/B mRNA and surface protein expressions in breast cancer cells treated with chemotherapeutic agents by real-time RT-PCR and flow cytometry respectively. The blocking effects of ataxia telangiectasia mutated and Rad3-related kinase (ATM/ATR) inhibitor caffeine and nuclear factor κB (NF-κB) inhibitor pynolidine dithiocarbamate (PDTC) on etoposide-upregulated MICA/B mRNA and surface protein expressions were investigated. Electrophoretic mobility shift assay (EMSA) was taken to investigate whether etoposide enhanced the binding of NF-κB to MICA/B gene promoter.@*RESULTS@#Three topoisomerase inhibitors etoposide, camptothecin and doxorubicine upregulated MICA and MICB mRNA expressions in breast cancer cell MCF-7. Comparing to no-drug-treated cells, MICA mRNA levels increased to (1.68±0.17), (2.54±0.25) and (3.42±0.15) fold, and levels of MICB mRNA increased to (1.82±0.24), (1.56±0.05) and (5.84±0.57) fold respectively in cancer cells treated by etoposide at the concentrations of 5, 20 and 100 μmol/L (P<0.05). MICA and MICB mRNA levels also increased significantly when MCF-7 cells were incubated with camptothecin or doxorubicine at the specific concentrations (P<0.05). MICB mRNA expression also increased slightly in another breast cancer cell SK-BR-3 treated by topoisomerase II inhibitors etoposide and camptothecin (P<0.05). Furthermore, etoposide and camptothecin upregulated MICA/B surface protein expression in MCF-7 cells (P<0.05), and the upregulation was found in both living and apoptotic cells. Our study showed that etoposide induced-MICA/B expression in MCF-7 was inhibited by caffeine at different concentrations. When cancer cells were treated by caffeine with 1, 5 and 10 mmol/L, MICA mRNA levels decreased from (3.75±0.25) to (0.89±0.05), (0.81±0.02) and (0.48±0.04) fold respectively (P<0.001), and MICB mRNA levels decreased from (6.85±0.35) to (1.36±0.13), (0.76±0.06) and (0.56±0.03) fold (P<0.05), while MICA/B protein levels decreased from (3.42±0.05) to (1.32±0.03), (1.21±0.06) and (1.14±0.03) fold (P<0.001), indicating that etoposide-induced MICA/B expression was inhibited by ATM/ATR inhibitor. Similarly, NF-κB inhibitor PDTC also inhibited MICA/B mRNA and protein expressions induced by etoposide significantly when MCF-7 cells were incubated with PDTC at the concentrations of 10, 50 and 100 μmol/L (P<0.05), indicating that NF-κB was also involved in this process. EMSA showed that the binding of NF-κB to MICA/B promoter enhanced in MCF-7 cells after etoposide treatment.@*CONCLUSION@#Topoisomerase inhibitor increased MICA/B mRNA and protein expressions in breast cancer cells, indicating that chemotherapeutic agents might increase the recognizing and killing ability of immunocytes to breast cancer cells. ATM/ATR and NF-κB pathways might be involved in it.

Bone marrow-derived mesenchymal stem cells regulate the proliferation and activity of natural killer cells / 中国实验血液学杂志

This study was aimed to explore the effect of bone marrow-derived mesenchymal stem cells (MSC) on proliferation and activity of natural killer (NK) and NK-T cells. MSC was co-cultured with peripheral mononuclear cells from healthy donors in presence of IL-2, phytohemagglutinin (PHA) and mouse anti-human CD3 McAb (culture condition known to expand NK cells). The ratio of NK cells and NK-T cells was measured by flow cytometry and the effect of MSC on killing activity of NK cells against K562 cells was detected by MTT method after co-cultured with different densities of MSC. The results showed that MSC inhibited the production of NK cells in a dose-dependent manner generally. At the densities of 0, 1 × 10(5) and 5 × 10(5)/ml, the ratios of NK cells in the co-culture conditions were (16.9 ± 4.6), (14.0 ± 8.6) and (6.4 ± 4.6), respectively (P < 0.05). However, MSC could promote the formation of NK cells at lower MSC density (1 × 10(4)/ml), the ratio of NK cells reached to (20.9 ± 7.1), which was higher than that of culture condition without MSC (P < 0.05). The different densities of MSC in the co-culture conditions had no much influence on the ratio of NK-T cells (P > 0.05). MTT assay showed that the killing activity of suspended cells in co-culture system against K562 cells was parallel with the ratio of NK cells. Different densities of MSC regulated bidirectionally killing activity of NK to K562 cells by regulating bidirectionally ratio of NK cells. It is concluded that the MSC can promote the formation of NK cells and enhance its activity against tumor cells in the lower doses, while suppress the formation of NK cells and attenuate its tumor-killing effect in higher dose condition.

Effects of quercetin on multidrug resistance and expression of related genes in human erythroleukemic K562/a cells / 中国实验血液学杂志

The study was aimed to investigate the effect of quercetin, flavonoid molecules on reversing leukemia multidrug resistance and its mechanism. K562/A cells were cultured in vitro with different concentrations of quercetin. Cell growth inhibition and adriamycin (ADR) sensitivity were detected by MTT method. Intracellular ADR concentration was determined by flow cytometry. Cell apoptosis was assayed by Annexin V/PI staining method. The expressions of drug transporter and apoptosis related genes were measured by real-time PCR array. The results indicated that quercetin inhibited the proliferation of K562 and K562/A in 5-160 µmol/L and with dose-dependent manner. Quercetin increased the sensitivity of K562/A cells to ADR in a low toxicity concentration. Flow cytometry showed that the quercetin increased the accumulation of ADR in K562/A cells when cells were co-cultured with 5 µmol/L ADR for 2 hours. Quercetin could induce the apoptosis of K562 and K562/A cells with dose dependent manner. Furthermore, some drug transport related genes such as ATP-binding cassette (ABC) and solute carrier (SLC) and some apoptosis-related genes such as BCL-2, tumor necrosis factor (TNF), tumor necrosis factor receptor (TNFR) families were down-regulated by quercetin. It is concluded that quercetin reverses MDR of leukemic cells by multiple mechanisms and the reversing effect is positively related to drug concentration.

Apoptosis-inducing effect of quercetin and kaempferol on human HL-60 cells and its mechanism / 中国实验血液学杂志

The purpose of this study was to explore the anti-leukemia effect of quercetin and kaempferol and its mechanism. The HL-60 cells were used as the leukemia models. The inhibitory effects of quercetin and kaempferol on growth of HL-60 cells was assessed by MTT assay. The effect of quercetin and kaempferol on cell cycle in HL-60 cells was detected by flow cytometry. The cytotoxic effect of these 2 drugs was analysed by single cell electrophoresis assay. Western blot analysis was used to study the apoptotic mechanism of HL-60 cells. The results showed that the quercetin and kaempferol had a significant anti-leukemia effect in vitro. The proliferation of HL-60 cells was significantly inhibited in dose-and time-dependent manners after treating with quercetin (r = 0.77) and kaempferol (r = 0.76) respectively, and the cytotoxicity of quercetin was superior to that of kaempferol. The quercetin and kaempferol induced G(2)/M arrest and apoptosis of HL-60 cells. The quercetin and kaempferol could down-regulate the survivin expression. It is concluded that the quercetin and kaempferol have significant anti-leukemia effect in vitro. Furthermore the apoptosis-inducing effect of quercetin is stronger than that of kaempferol, both of which induce apoptosis of HL-60 cells through depressing cell growth, arresting cell cycle and inhibiting expression of survivin.

Dendritic cells elicit cellular immune response by targeting to capture breast cancer cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the specific anti-breast cancer immune response induced by dendritic cells (DC) loaded with trastuzumab and apoptotic Her-2+ breast cancer cells.</p><p><b>METHODS</b>DCs were generated from healthy peripheral blood mononuclear cells (PBMCs) in the presence of recombinant cytokines GM-CSF, IL-4 and TNF-alpha. Mature DCs were harvested after 7 days' co-culture of PBMCs and trastuzumab-treated apoptotic SKBr3 cells. The morphologic characteristics and ultrastructure of the DC were observed under the inverted phase-contrast microscope and transmission electron microscope (TEM), respectively. Flow cytometry (FCM) was used to check the expression of several DC specific markers: CD14, CD1a, CD64, CD80, CD83, CD86, HLA-ABC and HLA-DR. DC-cytokine induced killer (DC-CIK) cells were prepared by co-culture of DCs and peripheral blood lymphocytes in the presence of anti-CD3 antibodies and human IL-2 at an appropriate concentration. The number of antigen-specific T cells was analyzed by human interferon gamma enzyme linked immunospot (ELISPOT) assay. MTT assay was employed to assess the lysis of breast cancer cell line induced by DC-CIK cells.</p><p><b>RESULTS</b>5 minutes after the adding of DCs to SKBr3 cells pretreated with trastuzumab, the apoptotic SKBr3 cells were found to be circled by DCs. 48 hours later, many membrane-wrapped organelles of the apoptotic target cells in the cytoplasm of DCs were found by TEM. The majority of the organelles were degraded. Fewer organelles from the apoptotic cells were found in DCs without Herceptin. More than 60% in every group of DCs expressed a high-affinity receptor for IgG (FcgammaRI or CD64). CD14 expression on the mature DCs were comparatively lower, and HLA-DR and HLA-ABC expressions were higher in the trastuzumab group. The expression of CD1a, CD80, CD83 and CD86 in trastuzumab group were higher than those in immature DCs group (P < 0.05). ELISPOT assay suggests that the spot number of antigen-specific T cells were higher in trastuzumab group than that in the antigen unloaded DCs group (P < 0.05). The lysis of SKBr3 cells induced by the SKBr3 antigen loaded DC-CIK cells were 1.7 times higher than that of CIK.</p><p><b>CONCLUSION</b>The lysis of SKBr3 cells induced by DC-CIK was increased after that DCs were combined with trastuzumab to capture antigen from SKBr3 cells. These findings support further investigation into the use of combination immunotherapy of the humanized monoclonal antibody, DC vaccines and immunological effector cells.</p>

Correlation of chemokine CCL-2/MCP-1 level in the plasma with aGVHD and idiophathic pneumonia syndrome after allogeneic hematopoietic stem cell transplantation / 中国实验血液学杂志

The aim of this study was to investigate the relationship between the plasma levels of chemokine CCL-2/MCP-1 and acute graft-versus-host disease (aGVHD) and/or idiopathic pneumonia syndrome (IPS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). ELISA assays were used to detect the plasma level of CCL-2/MCP-1 of 22 patients who received allo-HSCT, including 14 patients without or with grade I, 8 patients with grade II - IV aGVHD, respectively. 8 out of 22 patients were also diagnosed with IPS clinically. The dynamic changes of the plasma levels of CCL-2/MCP-1 chemokine and its correlation with aGVHD and/or IPS were analysized retrospectively. The results showed that the plasma levels of CCL-2/MCP-1 in the patients with moderate and serious aGVHD (grade II - IV) significantly increased, as compared with that prior to allo-HSCT (p < 0.05). The plasma levels of CCL-2/MCP-1 in the patients with aGVHD and/or IPS were higher significantly than those without any of these complications (p = 0.001). The retrospective analysis indicated that the plasma levels of CCL-2/MCP-1 in the patients with IPS significantly increased (p = 0.006). It is concluded that plasma level of CCL-2/MCP-1 correlates with aGVHD and/or IPS, and plays a role in the pathogenesis of these complications.

Human/mouse chimeric anti-CD20 monoclonal antibody enhances antigen presentation in dendritic cells and induces anti-lymphoma CTL effects / 中国实验血液学杂志

In order to investigate the cellular immunoresponses mediated by chimeric anti-CD20 monoclonal antibody (anti-CD20 McAb) through dendritic cells (DCs), mononuclear cells were isolated from human peripheral blood (PBMNC) and DCs from PBMNCs in vitro were generated with normal methods. Human CD20 positive lymphoma cell line-Raji cells were treated with different methods including treatment with anti-CD20 McAb (group R), treatment with heat-induced apoptosis (group A) and treatment with anti-CD20 McAb+heat-induced apoptosis (group R+A), then Raji cells treated with above-mentioned methods as tumor antigen were loaded on DCs. The phagocytosis of DCs to tumor antigen was observed by transmission electron microscope (TEM), the auto-mixed lymphocyte reaction was performed with antigen-primed DCs, the release of INF-gammafrom effector cells was detected by ELISPOT, the killing of effector cells on Raji cells was assayed by MTT. The results showed that under TEM, no pronounced phagocytosis of DCs was seen in group R, while the phagocytosis of apoptotic bodies could be easily seen in group A and the more cell fraqments were observed in group R+A. The FCM indicated that the expressions of CD80, CD86 and HLA-DR on DCs in 3 experimental groups were higher than those in group control (p<0.05), while expression positive rate in group R+A was higher than those in group R and A (p<0.05). The detection of lymphocyte surface antigen revealed that proportions of CD8+ cells in all experimental groups were higher than those in group control (p<0.05), count of CD56+ cells in group R and R+A increased, as compared with group A and control, difference was significant (p<0.05). ELISPOT assay indicated that amount of cells releasing IFN-gamma in all experimental groups was higher than that in group control, and also number of spots in group R+A significantly higher than that in other groups at effector-targetor ratio=1:10 (p<0.05). The results of killing assay demonstrated that killing rate on Raji cells in all experimental groups increased as compared with group control (p<0.05), while killing rate in group R+A was higher than that in group R and A. It is concluded that anti-CD20 McAb can mediate DC to induce cellular immunoresponse against lymphoma, that is, to stimulate and amplify specific CTLs and NK cells. Anti-CD20 McAb combined with DCs primed by heat-stressed tumor cells as antigen can further enhance cellular immunoresponse against lymphoma.

rhIL-11 accelerates the engraftment of platelets after unrelated cord blood transplantation / 中华血液学杂志

<p><b>OBJECTIVE</b>To observe whether rhIL-11 could accelerate the engraftment of platelets after unrelated cord blood transplantation (CBT).</p><p><b>METHODS</b>Nine patients (3 children and 6 adults) were enrolled in this study. The degree of HLA disparity was 0-2 loci. Cord blood was given two units for adults and one unit for children. Conditioning regimens were CY/TBI in 1 and BU/CY in 8 cases, both with antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and short-term methotrexate. On day +1, rhIL-11 was used at 50 microg x kg(-1) x d(-1) and G-CSF at 5 microg x kg(-1) x d(-1) to accelerate hematopoiesis recovery.</p><p><b>RESULTS</b>The median age of the patients was 22.3 years and the median weight 52.3 kg. Among the 9 patients, 8 (88.9%) experienced engraftment. The median time to neutrophil > 0.5 x 10(9)/L was 21.3 (14-37) days and to platelet > 20 x 10(9)/L was 25 (18-36) days. 42.9% of the patients developed grade I aGVHD and 33.3% developed localized chronic GVHD. Six patients were alive and disease-free at a median follow-up of 7 months. Infection was the primary cause of death. The expected 1-year survival was 77.8%, 2-year survival was 52.2%. Five of 8 patients (62.5%) who received IL-11 presented leakage syndrome. On prophylaxis with drugs containing Arnebia root extract, all patients could tolerate the treatment.</p><p><b>CONCLUSION</b>rhIL-11 maybe helpful for accelerating the platelet recovery and reducing aGVHD severity in unrelated CBT. The major side effect is leakage syndrome. It is well tolerated on prophylaxis with drugs containing Arnebia root.</p>

Immunological effector cells enhance apoptosis induced by adriamycin in a multi-drug resistant human breast cancer cell line / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effects of immunologic effector cells to enhance apoptosis induced by adriamycin (ADR) in multi-drug resistant human breast cancer cell line MCF7/ADR.</p><p><b>METHODS</b>The immunologic effector cells were induced and expanded by IFN-gamma, McAb CD3, IL-1 and IL-2. The expression of P-glycoprotein (P-gp) and its relation to apoptosis in target cells were detected by TUNEL technique and immunohistochemical staining. Flow cytometry (FCM) was carried out to determine the expression level of human breast cancer related P185 antigen and the positive rate of Annexin V-FITC/PI expression. The subcellular distribution of ADR and Annexin V expression in the target cells were detected by fluorescence microscopy.</p><p><b>RESULTS</b>The immunologic effector cells down-regulated the expression of P185 and P-gp in MCF7/ADR cells. The accumulation and subcellular distribution of ADR in MCF7/ADR cells were increased after co-culture with the immunologic effector cells. After treatment with the immunologic effector cells in combination with ADR, apoptosis rate of the target cells was 10 times higher than that induced by ADR alone, and 13 times higher than that induced by the immunologic effector cells alone.</p><p><b>CONCLUSION</b>Immunologic effector cells can simultaneously down-regulate the expression of P185 and P-gp in MCF7/ADR cell line, and increase the apoptosis rate of MCF7/ADR cells in combination with ADR.</p>

Effect of the new human transcription factor hBKLF on the proliferation, differentiation of K562 cell line and hemoglobin synthesis / 中国实验血液学杂志

The human basic Krüppel-like factor (hBKLF) is a newly cloned human transcription factor from the cDNA library of fetal liver. It belongs to the Krüppel-like transcription factor family. Previous expression study showed that it is a hematopoietic related factor. This study was aimed to investigate the effect of hBKLF on cell proliferation, differentiation and hemoglobin synthesis by using K562 cell line as model. The sense and antisense expression plasmids of hBKLF were constructed, and transfected into K562 cells by lipofectamine. After G418 selection for 4 weeks, the cell line with stable expression of the gene was obtained. Then the hBKLF expression level, proliferation ability, colony formation and hemoglobin production were detected by RT-PCR and Western blot, MTT method, methyl cellulose semisolid culture method and benzidine test respectively. The morphologic change of cell was observed with inverted microscope. The results showed that the sense plasmid could increase hBKLF level and antisense plasmid could decrease hBKLF expression. When hBKLF level was down-regulated, K562 cells could proliferate more quickly and synthesize more hemoglobin. But there were no differences in colony formation ability and no apparent morphologic change. It is concluded that hBKLF can inhibit hematopoietic cell proliferation and hemoglobin synthesis. It is suggested that hBKLF plays an important role in the proliferation and differentiation of hematopoietic cells.

Construction of recombinant vector expressing ALAS2 gene in X-linked sideroblastic anemia / 中国实验血液学杂志

X-linked sideroblastic anemia (XLSA) is caused by mutations of erythroid-specific 5-aminolevulinate synthetase (ALAS2) gene. In this study a eukaryotic expression vector of ALAS2 was constructed and transfected into eukaryotic cells to observe the expression of ALAS2 gene. The full length cDNA of ALAS2 gene was inserted into plasmid pDs-red2-N1, named pDs-red2-N1/ALAS2. Then, the vector was transfected into K562 cells via electroporation. At 48 hours after transfection, total RNA from K562 cells was extracted, expressions of ALAS2 gene and protein with red fluorescence in the K562 cells were detected by RT-PCR and flow cytometry, respectively. The vector was also transfected into COS 7 cells via liposome. Both mRNA and protein expression in COS7 cells were detected by RT-PCR and fluorescence microscopy. The result showed that after the pDs-red2-N1/ALAS2 eukaryotic expression vector was digested by KpnI and BamHI, two fragments of 4 700 bp and 1 764 bp were displayed by electrophoresis on agarose gel. Sequence method confirmed that the sequence was correct. RT-PCR amplified the total RNA extracted from the transfected K562 and COS7 cells, and could find mRNA of ALAS2 gene that can't be found in K562 and COS7 cells usually. The expressions of both fluorescein and ALAS2 were significantly increased. The percentage of positive cells reached about 19.2% and 10.7%, respectively. ALAS2 expression lasted for 10 days in COS7 cells and the peak was at the third day. It is concluded that the eukaryotic expression vector of ALAS2 gene is successfully constructed; K562 and COS7 cells transfected with the vector via electroporation and liposome can express ALAS2 protein. So, the vector has the potential in gene replacement and can be used for patients with XLSA in future.

Cytokine-induced killer cells showing multidrug resistance and remaining cytotoxic activity to tumor cells after transfected with mdr1 cDNA / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Routine treatment of cancer such as surgery, radiation or chemotherapy is sometimes unable to eradicate metastatic malignant cells. So we tried a new method and increased the adoptive immunotherapy of Cytokine-induced killer (CIK) cells in tumor patients and the multidrug resistance (mdr1) cDNA was transfected into CIK cells.</p><p><b>METHODS</b>CIK cells were obtained from peripheral blood and induced by IFN-gamma, anti-CD3 monoclonal antibody, IL-2 and IL-1. CIK cells were transfected with plasmid PHaMDR containing human mdr1 cDNA by electroporation. RT-PCR was used to detect mdr1 mRNA in transfected CIK cells. P-glycoprotein (P-gp) expressed on surface of CIK cells was assayed by FITC-conjugated anti-P-gp monoclonal antibody and flow cytometry. Multidrug resistance to doxorubicin and colchicine and cytotoxic activity to human breast cancer cell line MCF7 were performed using MTT method.</p><p><b>RESULTS</b>mdr1 mRNA was detected in transfected CIK cells. P-gp was expressed on the surface of the transfected CIK cells, and the P-gp positive cells reached 21% - 37% of the total CIK cells after transfection. The IC50 to doxorubicin increased to 22.3 - 45.8 times, and that to colchicines to 6.7 - 11.35 times, as compared to those of untransfected CIK cells. However, the cytotoxic activity to MCF7 cell line remained unaltered.</p><p><b>CONCLUSIONS</b>CIK cells were successfully transfected with mdr1 cDNA by using electroporation. The transfected CIK cells had the characteristics of multidrug resistance without change in their cytotoxic activity to tumor cells.</p>

CIK cells acquired multidrug resistance and maintained cytotoxic activity to tumor cells after mdr1 gene transfection / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate whether the cytokine-induced killer (CIK) cells could acquire multidrug resistance and maintain the original cytotoxic activity after multidrug resistance (mdr1) genes transfection.</p><p><b>METHODS</b>CIK cells were generated from peripheral blood cultured with IFN-gamma, CD(3) monoclonal antibody, IL-2, IL-1 and transfected with a plasmid (pHamdr) containing human mdr1 gene via electroporation. RT-PCR method was used to assay mRNA expression of mdr1 gene in transfected CIK cells, flow cytometry with anti-P-gp monoclonal antibody to detect P-glycoprotein (P-gp) expression on CIK cells membrane, and MTT assay to compare both the multidrug resistance to doxorubicin and colchicines and cytotoxic activity to human mammary cancer cell line MCF7 between transfected and non-transfected CIK cells.</p><p><b>RESULTS</b>mdr1 expression was detected in the transfected CIK cells. There was a strong expression of P-gp on the transfected CIK cells and the percentages of P-gp positive cells were 21% - 37% (average 27%). The IC(50) of transfected CIK cells to doxorubicin was 22.3 - 45.8 times and 6.7 - 11.35 times to colchicines of those of non-transfected CIK cells. The cytotoxic activity to MCF7 remained unchanged (P > 0.05).</p><p><b>CONCLUSION</b>It demonstrated that CIK cells transfected with mdr1 gene via electroporation could express multidrug resistance successfully without changes of cytotoxic activity.</p>

Reversal effect of berbamine on multidrug resistance of K562/A02 cells and its mechanism / 中国实验血液学杂志

This preject is to explore the reversal efficacy of calmodulin antagonist berbamine (BBM) on multidrug resistance (MDR) and its mechanism. Human erythroleukemic cell line K562 and its adriamycin-resistant counterpart K562/A02 were used in the study. The cells were co-cultured with ADR and BBM in different concentrations. MTT assay was used to analyze the effect of BBM on cell growth inhibition. According to the MTT assay, the 50% inhibitory concentration (IC(50)), the multiples of drug resistance and increased sensitivity of ADR were calculated. The concentration of intracellular ADR and expression level of P-gp were detected by flow cytometry (FCM). The expression level of mdr1 mRNA and survivin mRNA was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) with beta-actin as internal reference. The results showed that IC(50) of ADR in K562 and K562/A02 cells was 1.16 +/- 0.09 micro mol/L and 37.47 +/- 1.76 micro mol/L, respectively. The resistant multiple of K562/A02 cells to ADR was 32.30 higher than that of K562 cells. BBM increased the chemo-sensitivity of ADR in K562/A02 cells with dose-dependent relationship, i.e. when 5, 10 and 20 micro mol/L BBM was added in the culture the chemo-sensitivity of ADR was increased to 2.01-, 9.68-, and 41.18-fold (P < 0.01), respectively. After treating K562/A02 cells by 5 or 10 micro mol/L BBM for 2 hours the accumulation of intracellular ADR was increased to 1.41- and 1.52-fold (P < 0.01), respectively. Treating by BBM for 72 hours decreased 4.12% (P < 0.05) and 27.09% (P < 0.01) of P-gp expression, respectively, meanwhile down-regulated expression of mdr1 mRNA and survivin mRNA was found. In conclusion, BBM could increase intracellular concentration of ADR in K562/A02 that down-regulated expression level of mdr1 mRNA and P-gp and survivin so that the sensitivity of K562/A02 to ADR was increased significantly.

The experimental study on the idiotypic nucleic Acid vaccine constructed from the genomic DNA to lymphoma / 中国实验血液学杂志

This study was to investigate the anti-lymphocytic malignancy immunologic effects induced by two types of the idiotypic nucleic acid vaccines which were constructed from the genomic DNA and RNA of the human B lymphoma cell line respectively. Namalwa cell line and BALB/c mice were used as the models. The gene fragments of the IgH variable region (IgHV), which were obtained from the genomic DNA and RNA of Namalwa cell respectively, were cloned into the eukaryocytic expression vector pcDNA 3.0 to be used as the idiotypic nucleic acid vaccines. After transfecting COS cells with one of vaccines constructed from the genomic DNA by using LipofectAMINE, the result of transcription was identified by using RT-PCR. The experimental mice were immunized by intramuscular injection with two types of vaccines. The specific anti-idiotypic antibody was detected by indirect immunofluorescence assay. The results showed that the nucleic acid vaccine constructed from the genomic DNA can be transcribed in COS cells, the transcription product turned shorter, and the intron region of 86 bp was spliced accurately. When immunizing the mice, two vaccines both induced the anti-idiotypic antibody against Namalwa cell, the anti-idiotypic antibody could be detected since detected since after immunization, and got to the peak of titer on the sixth week. It was concluded that the nucleic acid vaccines against lymphoma can be constructed from both the genomic DNA and RNA.

Inhibitory effect on proliferation of KG1a cell line by methyltransferase inhibitors / 中国实验血液学杂志

To explore the possibility of a new therapeutic strategy for leukemia by intervening in the DNA methylation to re-express p15 suppressor gene, methylation inhibitors, 5-Aza-2'-deoxycytidine (5-Aza-CdR) and cell differentiation agent (CDAII) were used to treat myelogenous leukemia cell line KG1a in which p15 gene expression was suppressed due to DNA hypermethylation. The biological characteristics of KG1a cells untreated or treated with the agents were investigated and analyzed using morphology, methylation specific-PCR (MSP), (3)H-labeled microassay technique, restriction endonuclease reaction, flow cytometry and immunofluorescence methods. The results indicated that both agents showed concentration-dependent and time-dependent inhibition of cell proliferation. 5-Aza-CdR and CDAII induced apoptosis and cell differentiation with G(2) and G(0)/G(1) arrest respectively. Furthermore, DNA methyltransferase activity and level of methylation in genomic DNA were decreased and p15 protein was re-expressed partially. It is concluded that it is possible to treat leukemia by intervening in the DNA methylation using methyltransferase inhibitors and it is worth to make a thorough study on mechanism of the new strategy.

Cytokine-induced killer cells induce apoptosis of K562 cells expressed bcr-abl / 中国实验血液学杂志

In order to investigate whether cytokine-induced killer (CIK) cells can induce apoptosis of bcr-abl(+) K562 cells, apoptosis of K562 cells and CEM cells induced by CIK cells, etoposide or camptothecin was detected with flow cytometry DNA assay. RT-PCR showed that K562 cells expressed the bcr-abl fusion gene, K 562 cells, K562 cells/etoposide or K562 cells/camptothecin groups showed no sub-G(1) peak. K562 cells/CIK cells group showed sub-G(1) peak (38.1%). CEM cells showed no sub-G(1) peak. CEM cells/camptothecin or CEM cells/etoposide groups showed sub-G(1) peak (23.5% or 32.3% respectively). CEM cells/CIK cells group showed sub-G(1) peak (45.4%). Etoposide or camptothecin did not induce apoptosis of K562 cells. CIK cells induce apoptosis of K562 cells. Bcr-abl fusion gene prevented apoptosis induced by etoposide or camptothecin, but did not prevent apoptosis induced by CIK cells. This property may support the observed adoptive immunologic effect of allogeneic bone marrow transplantation and donor lymphocyte transfusions of CML case relapsing after allogeneic bone marrow transplantation.