OBJECTIVETo explore the feasibility and efficiency of immunotherapy with dendritic cell (DC) in leukemic mice model after allogeneic bone marrow transplantation (allo-BMT).

METHODSMature DC were expanded from mice bone marrow mononuclear cells (MNC) by adding mouse granulocyte-macrophage colony stimulating factor (mGM-CSF) and interleukin-4 (mIL-4). Three days later they were pulsed with frozen thawing L7212 leukemia-related antigen. Mice bearing leukemia received allo-BMT at d 0, and then were divided into control group (A), T cells group (B) and DC + T cells group (C) to receive respective immune therapy at d 14. The survival rate, survival time, occurrence of graft-versus-host disease (GVHD), cytotoxicity of spleen cells and serum cytokine level were observed. The survivors in each group were rechallenged with L7212 cells to observe the immune response to the leukemia.

RESULTSMature DC were successfully induced from bone marrow MNC. In groups B and C, the relapse rates were 30% and 0%, while the long term survival rates after BMT was 30% and 70% respectively. Both of the differences were statistically significant (P < 0.05). However, the incidence of GVHD in these two groups were similar. The mean survival times were (32.95 +/- 13.29) days and (41.15 +/- 13.88) days, respectively (P < 0.01). MTT assay indicated that spleen cells from group C had specific killing activity to L7212 cells. Enzyme-labeled immunosorbent assay (ELISA) showed that the serum IL-2 level in group C was (419.75 +/- 26.66) pg/ml, being significantly higher than that in the other two groups (P < 0.01). When the survivors were rechallenged with L7212 cells, there was difference between the survival rates of groups C and B (85.7% vs 33.3%, P < 0.05).

CONCLUSIONImmunotherapy with leukemia related antigen-pulsed DC in combination with donor lymphocyte infusions is an effective approach to reinforce GVL effect and decrease relapse after allo-BMT.

Animals ; Bone Marrow Cells ; cytology ; drug effects ; immunology ; Bone Marrow Transplantation ; Cancer Vaccines ; immunology ; Cell Differentiation ; Dendritic Cells ; immunology ; Female ; Graft vs Leukemia Effect ; Immunotherapy ; Leukemia, Experimental ; immunology ; surgery ; therapy ; Male ; Mice ; Mice, Inbred BALB C ; Survival Rate ; Transplantation, Homologous

OBJECTIVETo explore the pathogenesis of idiopathic thrombocytopenic purpura (ITP) and improve the differential diagnosis from myelodysplastic syndromes (MDS).

METHODSPolymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was performed to detect the point mutation of codon 12,13 in N-ras gene and codon 301, 969 in fms gene in adult and aged ITP and MDS patients.

RESULTSIn 25 ITP patients, N-ras mutation and fms mutation were detected in one each (4%). Mutations were found in 3 of 8 MDS patients: two (25%) with N-ras mutation and one (12.5%) with fms mutation.

CONCLUSIONSPatients with N-ras or fms gene mutation diagnosed as MDS rather than ITP.

Adult ; Aged ; Female ; Genes, fms ; genetics ; Genes, ras ; genetics ; Humans ; Male ; Middle Aged ; Myelodysplastic Syndromes ; genetics ; Point Mutation ; Polymerase Chain Reaction ; Polymorphism, Single-Stranded Conformational ; Purpura, Thrombocytopenic, Idiopathic ; genetics

To establish lentivirus-mediated system of double suicide genes and explore its killing effects on K562 cells, lentivirus transfer vector for double suicide genes was constructed using molecular methods, three plasmids of lentivirus gene transfer vector system were transferred into packaging cell line 293T using lipofectine method, the transfer effect was observed through fluorescence microscopy, the lentivirus particles were observed by means of electron microscopy. High titer of lentivirus was harvested from the supernatant of virus-producing cell culture and concentrated by high-speed centrifugation with Poly-L-Lysine (PLL). The K562 cells were infected with the concentrated supernatant containing the virus with the double suicide genes. Fluorescence microscopy and RT- PCR confirmed the integration and expression of extraneous gene. The cytotoxicity to these transgenic cells treated with 5-FC and GCV was measured by MTT assays. The growth inhibition ratio (GIR) of cells and inhibition concentration 50 (IC(50)) were counted. After administration of GCV and 5-FC, the changes of those cells were observed through scanning electron microscope. The results showed that lentivirus transfer vector with double suicide genes was constructed successfully. The above-mentioned plasmids were effectively transferred into 293T cells. So much green fluorescence was observed through fluorescence microscope. A lot of lentivirus particles were observed through transmission electron microscope. Double suicide genes mediated by lentivirus were stably integrated and expressed in K562 cells after infection with the concentrated virus using fluorescence microscopy and RT-PCR. The GIR of K562 cells using GCV or 5-FC was 48.73% or 50.69% respectively and it was apparently higher than that of untransfected cells (P < 0.01). When using GCV and 5-FC together, the GIR was 87.69%, which was apparently higher than that of group using GCV or 5-FC alone (P < 0.01). In conclusion, lentivirus-mediated gene transfer system could transfer CD and TK double suicide genes into K562 cells with high efficiency and it had strong killing effects when giving 5-FC and/or GCV. The cytotoxic effects of double suicide genes were superior to that of single suicide gene. The lentivirus-mediated double suicide gene transfer system is a high-efficiency gene transfer vector.
Cytosine Deaminase ; genetics ; Flucytosine ; pharmacology ; Ganciclovir ; pharmacology ; Genetic Therapy ; Genetic Vectors ; genetics ; HIV-1 ; genetics ; Humans ; K562 Cells ; Thymidine Kinase ; genetics

OBJECTIVETo selectively knockdown the expression of Angiotensin II receptor subtype 1a (AT1aR) in rat vascular smooth muscle cells (VSMCs) by RNA interference and the sequential effects on cellular viability and proliferation.

METHODSThe primary cultured rat aortic VSMCs were transfected by plasmids pAT1a-shRNA1 and pAT1a-shRNA2, each carrying an U6 promoter and an AT1a-specific shRNA-coding template sequence, or by a control plasmid pGenesil-Control (pCon) carrying a nonspecific shRNA-coding sequence. The mRNA and protein expressions of AT1a, AT2 were analyzed by semi-quantified RT-PCR and Western blot, respectively and normalized to the internal control gene beta-actin. Cellular viability and proliferation were determined with methylthiazoletetrazolium (MTT) assay.

RESULTSAT1a mRNA and protein were reduced by 82% and 69% by pAT1a-shRNA1, 77% and 56% by pAT1a-shRNA2, respectively while no change was found in pCon treated VSMCs. AT2 receptor level in VSMCs remains unchanged after various treatments. The A(490nm) values obtained by MTT measurements were similar among groups in the absence of Ang II but decreased significantly in pAT1a-shRNA1 and pAT1a-shRNA2 treated VSMCs in the presence of Ang II.

CONCLUSIONRNA interference can selectively knockdown AT1a expression in cultured VSMCs and attenuate the Ang II induced cell proliferation. Future studies are warranted to explore the potential role of RNA interference on AT1 function and as a new gene therapy tool for cardiovascular diseases.

Animals ; Cells, Cultured ; Gene Knockdown Techniques ; Male ; Muscle, Smooth, Vascular ; metabolism ; Plasmids ; RNA Interference ; RNA, Small Interfering ; Rats ; Rats, Sprague-Dawley ; Receptors, Angiotensin ; metabolism ; Transfection

OBJECTIVETo explore the spatial genetic structure of two HIV-I-resistant polymorphisms (CCR2-64 I and SDF1-3'A) alleles in the population of Shandong Province, China.

METHODSUsing the techniques of spatial stratified sampling and spatial statistics, the spatial genetic structure of the locus (CCR2-64 I and SDF1-3'A), which was shown to be important co-receptor for HIV infection, was quantified from the populations of 36 sampled counties of Shandong Province, and a total of 3147 and 3172 samples were taken for testing CCR2-64I and SDF1-3'A respectively from individuals without known history of HIV-I infection and AIDS symptoms.

RESULTSThere were significantly spatial genetic structures of the two alleles at different spatial distance classes on the scale of populations, but on the scale of individuals, no spatial structure was found in either the whole area of Shandong Province or the area of each sampled county. Although the change of frequencies of the two alleles with geographic locations in Shandong Province both showed gradual increase trends, their changing directions were inverse. The frequency of CCR2-64I allele gradually increased from the southwest to the northeast, while the frequency of SDF1-3'A allele gradually increased from the northeast to the southwest. However the RH to AIDS of combined types of their different genotypes did not represent obvious geographic diversity on the whole area of the Province.

CONCLUSIONThe frequency of allele usually has some spatial genetic structures or spatial autocorrelation with different spatial distance classes, but the genotypes of individuals have random distribution in the same geographic area. Evaluating spatial distribution of the genetic susceptibility of HIV (AIDS) to CCR2-64I and SDF1-3'A alleles, should focus on the frequencies of combined genotypes of CCR2 and SDF1 based on the two-locus genotypes of each individual rather than the frequencies of CCR2-64I and SDF1-3'A alleles.

Acquired Immunodeficiency Syndrome ; epidemiology ; genetics ; Chemokine CXCL12 ; Chemokines, CXC ; genetics ; China ; epidemiology ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; HIV-1 ; Humans ; Immunity, Innate ; genetics ; Mutation ; Polymorphism, Genetic ; Receptors, CCR2 ; Receptors, Chemokine ; genetics

OBJECTIVETo construct two recombinant plasmids of mdr1 and mcl1 shRNA, and to investigate their reversal effect on drug resistance in K562 adriamycin resistant cell lines (K562/A02).

METHODSTwo oligonucleotides of mdr1 and mcl1 gene were designed referring to that of GenBank, double-stranded DNA was derived through annealing, and cloned into pRNAT vector digested by two restricted endoenzymes. K562/A02 cells were transfected with the recombinant plasmids. The mdr1 mRNA expression and its protein product P-glycoprotein (P-gp) were detected by RT-PCR and flow cytometry. The expression of mcl1 gene was detected by RT-PCR. 50% inhibition concentration (IC50) of adriamycin (ADM) on K562/A02 cells was determined by MTT method. Cells apoptosis was analyzed by flow cytometry.

RESULTSComparing with K562/A02 cells, the shRNA of mdrl or mcl1 gene in vitro can remarkably increase the sensitivity of K562/A02 to adriamycin, down-regulate mdr1 or mcl1 gene expression, increase the K562/A02 cells apoptosis rates induced by adriamycin. Cotransfection of mdrl and mcl1 genes shRNA can also down-regulate the expression of their gene, more remarkably increase the sensitivity and apoptosis of K562/ A02 to adriamycin.

CONCLUSIONTransfection of mdrl or mcl1 gene shRNA can promote the sensitivity of K562/A02 to adriamycin and cotransfection of the two shRNA can more remarkably do so. The mel1 gene might be involved in adriamycin resistant in K562/A02 cells.

ATP-Binding Cassette, Sub-Family B, Member 1 ; biosynthesis ; genetics ; Apoptosis ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Flow Cytometry ; Gene Expression ; Humans ; K562 Cells ; Myeloid Cell Leukemia Sequence 1 Protein ; Neoplasm Proteins ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; RNA Interference ; RNA, Messenger ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

This study was aimed to investigate the effect of CD44 gene silence on the drug resistance and biologic activity of human multidrug resistant leukemia cell line K562/A02. The oligonucleotides of CD44 gene were designed according to related data of GenBank, double-stranded DNA was produced by annealing, and was inserted into pGCsilencerU6/Neo/GFP vector. The resultant recombinant plasmid pGCsiRNA-CD44 was transfected into K562/A02 cell line. Expressions of CD44, mdr-1 and blc-2 mRNA were assayed by real time RT-PCR. The 50% inhibitory concentration (IC50) of doxorubicin (ADM) for K562/A02 cell line was determined by MTT method. Cell cycle was determined by flow cytometry. The morphology of apoptotic cells was examined by Hochst 33258 staining. The results indicated that the siRNA eukaryotic plasmid directing at CD44 gene could effectively silence the CD44 gene of K562/A02 cells; as compared with control group, the CD44 expression in K562/A02 cells transfected with 4 pGCsiRNA-CD44 plasmids was obviously inhibited, while the inhibition of CD44 expression in cells transfected with siCD44-1 was strongest. After being transfected with pGCsiRNA-CD44, the expression of CD44 mRNA in K562/A02 cells reduced by 64.1% (p<0.05), at the same time the expression of mdr-1 and bcl-2 mRNA in pGCsiRNA-CD44-transfected K562/A02 cells reduced by 25.6% and 50.8% respectively. IC50 of K562/A02 cells after transfection decreased to (8.77+/-1.63) microg/ml and was obviously lower than that of control (17.97+/-1.61) microg/ml (p<0.01). After transfection for 48 hours, the ratio of K562/A02 cells in G0/G1 increased by 10.7%, and the cells displayed karyopyknosis, nuclear margination and apoptotic bodies. It is concluded that the siRNA plasmid specifically targeting CD44 gene can remarkably down-regulate the expression of CD44 gene, inhibit K562/A02 cell proliferation, induce its apoptosis and effectively reverse the multidrug resistance of K562/A02 cells.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Gene Silencing ; Genetic Vectors ; Humans ; Hyaluronan Receptors ; genetics ; K562 Cells ; RNA, Small Interfering

OBJECTIVETo explore the feasibility and efficiency of cytosine deaminase (CD)/thymidine kinase (TK) gene-modified donor T cells used in allogeneic bone marrow transplantation (allo-BMT) as an approach to mitigate GVHD without compromising engraftment.

METHODSThe pseudotyped lentivirus vectors containing CD and TK double suicide genes were transfected with lipofectine to donor T cells. Lethally irradiated 615 leukemia mice were transplanted with BALB/c bone marrow plus CD(+)TK(+)T cells. GVHD prophylaxis was by administration of ganciclovir (GCV) and 5-Fluoride cytosine (5-FC).

RESULTSThe pseudotyped lentivirus-mediated gene transfer system could efficiently transfer CD and TK double suicide genes into donor T cells. Administration of GCV and 5-FC to the mice could markedly potentiate the CFU-S and CFU-GM yields and raise the number of peripheral white blood cells. 1 x 10(7) CD(+)TK(+) allogeneic T cells caused GVHD of a similar magnitude and time course to that of fresh, naive T cells after allo-BMT. Administration of GCV and 5-FC in mice received CD(+)TK(+)T cells reduced the severity of GVHD and resulted in significantly longer survival as compared with non-administration mice, and the effect was stronger than that of administration of GCV or 5-FC alone.

CONCLUSIONAdministration of CD + TK gene-modified donor T cells to recipient in allo-BMT might be an approach to mitigate GVHD without compromising alloengraftment.

Animals ; Body Weight ; Bone Marrow Transplantation ; Cytosine Deaminase ; genetics ; Female ; Genetic Therapy ; Graft vs Host Disease ; pathology ; therapy ; Lentivirus ; genetics ; Mice ; Mice, Inbred BALB C ; Thymidine Kinase ; genetics ; Transplantation, Homologous

OBJECTIVETo investigate the effect of DNA methylation in combination with histone deacetylase inhibitor on transcription regulation of Ras associated domain family gene 1(RASSF1A) tumor suppressor gene and the molecular biological behaviors in U266 cells.

METHODSThe U266 cells were treated with different doses of 5-Aza-2'-deoxycytidine (5-Aza-CdR) and Valproate (VPA) each alone or in combination. Methylation-specific PCR (MSP) was used to detect CpG island methylation in RASSF1A promoter. Quantitative real-time reverse transcription polymerase chain reaction (RQ-PCR) was used to examine the expression of RASSF1A gene in U266 cells. MTT was used for cell proliferation. Cell apoptosis and cell cycle were analyzed by flow cytometry.

RESULTSThe methylation of RASSF1A gene promoter was detected in U266 cells, while there was little RASSF1A gene expressing in the control group. The demethylation effect could be detected in the 5-Aza-CdR treated and combined treatment groups but no in the VPA group. The expression level of RASSF1A was induced by 5-Aza-CdR in a concentration-dependent manner while VPA had no such effect. The expression level of RASSF1A mRNA was increased significantly in the combined treatment group. Higher growth inhibition and apoptosis effects were found in 5-Aza-CdR and VPA combination group than that in 5-Aza-CdR or VPA alone group (P < 0.05). After treatment with 5-Aza-CdR or VPA alone for 72 h, more cells were arrested in G(0)/G(1) phase as conpared with control group (P < 0.05), and even more cells were so arrested in combined treatment group (P < 0.05).

CONCLUSIONDNA methylation and histone deacetylase inhibitor can synergistically induce demethylation of the RASSF1A gene, re-express RASSF1A gene silenced in U266 cells, inhibit the proliferation of U266 cells and induce cell apoptosis.

Cell Line, Tumor ; CpG Islands ; DNA Methylation ; Gene Expression ; Histone Deacetylase Inhibitors ; Humans ; Promoter Regions, Genetic

OBJECTIVETo investigate the in vitro effect of HSV-tk/GCV using a hTERT promoter-driven vector system on Skov3 ovarian cancer cells.

METHODSAn expression vector (pBTdel-279-tk) containing tk gene under the hTERT promoter was constructed by molecular biological methods, and then was transfected into Skov3 ovarian cancer cells, normal ovarian epithelial cells (NOEC) and human embryonic lung fibroblast by cationic liposome. Following the transfection with tk, GCV was added, and MTT and flow cytometry methods were applied to investigate its antitumor effect. RT-PCR was used to detect the tk gene in ovarian cancer cells and normal cells after the transfection of pcDNA3-tk or pBTdel-279-tk.

RESULTSpBTdel-279-tk/GCV system induced apoptosis in hTERT-positive ovarian cancer cells, but not in hTERT-negative normal ovarian epithelial cells and fibroblasts. The hTERT promoter system was almost as efficient in inducing cancer cell death as the CMV promoter. tk gene was expressed in Skov3 cells and NOEC after pcDNA3-tk transfection, while positive was only in ovarian cancer cells after pBTdel-279-tk transfection.

CONCLUSIONThe telomerasespecific transfer of the tk gene under the hTERT promoter is a novel targeting approach for the treatment of ovarian cancer and may lead to an effective and specific gene therapy.

Apoptosis ; genetics ; Cystadenocarcinoma, Serous ; genetics ; pathology ; DNA-Binding Proteins ; Female ; Ganciclovir ; pharmacology ; Genetic Therapy ; Humans ; Ovarian Neoplasms ; genetics ; pathology ; Promoter Regions, Genetic ; genetics ; Simplexvirus ; genetics ; Telomerase ; genetics ; Thymidine Kinase ; genetics ; Transfection ; Tumor Cells, Cultured