Resveratrol-downregulated phosphorylated liver kinase B1 is involved in senescence of acute myeloid leukemia stem cells.

Senescence is an important obstacle to cancer development. Engaging a senescent response may be an effective way to cure acute myeloid leukemia (AML). The aim of this study was to examine the effect of resveratrol-downregulated phosphorylated liver kinase B1 (pLKB1) on the senescence of acute myeloid leukemia (AML) stem cells.

[Mechanism involving blm gene underlies repair of DNA damage of Jurkat cells induced by mitomycin C].

The defect or block of apoptosis is an important factor involved in the drug resistance of tumor cells. Blm gene plays a great role in DNA damage and repair. This study was aimed to explore the relationship of blm gene expression with cell cycle and apoptosis after Jurkat DNA damage.

[Effect of MLL-AF9 fusion gene silence of acute monocytic leukemia cell line THP-1 on cyclin-dependent kinase inhibitor p27 expression].

Objective: To explore the effect of MLL-AF9 fusion gene silence on p27 expression and transcription regulation in THP-1 cells.

Methods: Small interference RNA (siRNA) fragments targeting THP-1 cells specific MLL-AF9 fusion gene were designed and constructed, and transfected into THP-1 by lipofectamine. Flow cytometry was used to detect siRNA transfection efficiency.

[Effect of down-regulating mll-af9 gene expression on proliferation of acute monocytic leukemia cell line THP-1].

This study was aimed to investigate the effect of small interfering RNA (siRNA) on the expression of mll-af9 oncogene and the proliferation of human acute monocytic leukemia cell line THP-1. One group of siRNA was designed targeting mll-af9 mRNA and finally obtained by chemosynthesis. Then the obtained siRNA was transfected into cultured human acute monocytic leukemia cell line THP-1 by lipofectamine.

[Enhancement of Fas-mediated apoptosis in leukemic cell line HL-60 by Bay 11 - 7082].

The aim of study was to explore the effects of NF-kappaB inhibitor Bay 11 - 7082 on Fas/FasL system and Fas-mediated apoptosis in HL-60 cells. The mRNA and protein expression levels of Fas, FasL and XIAP after treatment with Bay 11 - 7082 were detected by RT-PCR and FCM respectively. The level of sFasL was detected by ELISA before and after treatment with Bay 11 - 7082; apoptosis was detected by FCM before and after treatment with Bay 11 - 7082.

hMRE11 plays an important role in U937 cellular response to DNA double-strand breaks following etoposide.

MRE11 plays an important role in the signal transduction of DNA damage response, therefore this study was purposed to explore the relationship between hMRE11 focus formation and DNA double-strand breaks (DSBs) caused by etoposide (VP-16) in human promonocytic cells U937. After U937 cells were treated with VP-16, the drug-induced DSBs were assessed by pulsed-field gel electrophoresis (PFGE), the gene transcription levels of hMRE11 were evaluated by RT-PCR, the nuclear focus formation of hMRE11 protein was examined using immunofluorescence technique, the cell cycle in parallel was analyzed by flow cytometry. The results showed that the percentage of U937 cells with DSBs induced by VP-16 raised from 13.

Comparison of immunophenotype and clinical manifestations between patients with M5a and M5b of acute monocytic leukemia.

Acute monocytic leukemia is a distinct subtype of acute myeloid leukemia (AML) with characteristic biology and clinical features. This study was designed to compare the immunophenotypical features and clinical manifestations of the patients with AML-M(5a) to that of patients with AML-M(5b), and to identify differences between M(5a) and M(5b) and to explore their relations. A total of 58 cases of de novo adult patients with AML M(5) were investigated.

Depressing the immune escape of acute myelomonocytic leukemia via an anti-Fas ribozyme.

In order to investigate the inhibition role of anti-Fas hammerhead ribozyme on Fas expression and Fas-mediated apoptosis in CTLL-2 cells (mouse CTL cell line), and to explore a new way for enhancing the ability of T cells against Leukemia in donor lymphocytes infusion, CTLL-2 cells were transfected with pEGFP-RZ596 and pEGFPC1 (mock-transfected) via electroporation. Fas expression on CTLL-2 cells was detected by RT-PCR and Western blot. The killing effect of CTL against WEHI-3 (mouse acute myelomonocytic leukemia cell line) highly expressing FasL in vitro was detected by MTT assay.

Comparison of cytogenetics and clinical manifestations between M5a and M5b of acute monocytic leukemia.

To compare the cytogenetic difference between M5a and M5b of acute monocytic leukemia and to study the correlation between karyotypes and clinical manifestations, a total of 58 cases of de novo adult AML M5 have been investigated. Chromosome metaphases of bone marrow cells were prepared by using direct method and 24 hours short-term culture. The karyotypes were analyzed by G-banding.

[Expression of immune response molecules and function of fas ligand on surface of AML WEHI-3 cells].

The purpose of this study was to investigate the expression of Fas, Fas ligand (FasL) and CD80 and function of FasL on the surface of acute myelomonocytic leukemia cells from WEHI-3 line. The expression of Fas, FasL and CD80 on the surface of WEHI-3 were detected by flow cytometry, the apoptosis of YAC-1 cell induced by FasL on the surface of WEHI-3 were detected by (3)H-TdR incorporation. The results showed that the expression rate of Fas, FasL and CD80 on the surface of WEHI-3 cells were (6.

[Blocking the escape of leukemic cells from killing of T cell by combining anti-Fas ribozyme and CD80-IgG fusion protein].

Objective: To study Fas expression regulation of cytotoxic T lymphocyte(CTL)via anti-Fas ribozyme, increasing of CD80 epitope on the surface of acute myelomonocytic leukemia cells by CD80-IgG fusion protein and their effects on the apoptosis and killing ability against acute myelomonocytic leukemia cells of CTL.

Methods: A hammerhead ribozyme gene targeting the Fas mRNA was synthesized and its expression vector pEGFP-RZ596 was constructed and transfected into the mouse spleen T cells via electroporation. The Fas expression on T cells was detected by RT-PCR and Western bloting.

Cytobiological and clinicobiological features of AML with 11q23 chromosome abnormalities.

To investigate the interrelationship among morphology, immunology and clinical features in adult acute myeloid leukemia cases with 11q23 chromosome abnormalities, 210 newly diagnosed AML patients were retrospectively analyzed by cell morphology, immunophenotyping, G-banding or R-bamding analysis and clinical features. The results showed that 13 cases were found with 11q23 rearrangements or deletion (the incidence rate was 6.19%.

[Expression of BLM mRNA in six tumor cell strains].

The mutations of BLM gene may result in Bloom's syndrome which includes immunodeficiency, predisposition to malignant tumors and so on, and enhances sister chromati exchange (SCE), DNA replication failure, genome instability, and increases cancer susceptibility. This study was aimed to investigate the variability of mRNA expression level and cDNA structure of BLM gene in tumor cell strains so as to look for a new cancerogenic mechanism and to find a new therapeutic target. The expression level of mRNA and the structure of cDNA of BLM gene in six tumor cell strains and the normal human bone marrow mononuclear cells were detected with RT-PCR and DNA sequencing was performed.

[Recombinant adenovirus mediated hVEGF165 gene transfer promotes recovery of hematopoiesis in post-BMT mice].

To investigate the effects of vascular endothelial growth factor (VEGF) on the recovery of hematopoiesis in post-BMT mice, the recombinant adenovirus Ad-EGFP/hVEGF(165) was injected into syngeneic BMT BALB/c mice via the tail vein. At day 10, 20, 30 after BMT, the in vivo expression of hVEGF(165) was measured. At the same different time points, the numbers of WBC, Plt, RBC in peripheral blood and MNC in bone marrow were counted.

Impact of trisomy 8 on cytobiological and clinical features of acute myelomonocytic and monocytic leukemia.

To evaluate the impact of trisomy 8 on cytobiological and clinical features of acute myelomonocytic and monocytic leukemia (M(4), M(5)), a total of 56 cases of acute myelomonocytic and monocytic leukemia were investigated. Karyotypes were analyzed by G-banding or R-banding. The immunotypes in all cases were detected by flow cytometry.

Inhibitory effect of anti-fas ribozyme on apoptosis of mouse T cells.

Background & Objective: Tumor cells can express FasL, and induce apoptosis of activated T cells expressing Fas, which is so called "Fas counterattack". This study was to investigate inhibitory effect of anti-Fas ribozyme on apoptosis of mouse T cells, and explore a new way to enhance antitumor ability of T cells.

Methods: A hammerhead ribozyme targeting Fas mRNA was synthesized, its in vitro cleavage reaction was performed.

[Experimental study of inhibiting CTLL-2 cell apoptosis and enhancing cytotoxicity to Yac-1 cell by hammerhead ribozyme].

Objective: To investigate the inhibition role of anti-Fas hammerhead ribozyme on Fas expression and Fas-mediated apoptosis in mouse cytotoxic T lymphocyte (CTL) cell line--CTLL-2 cells, and explore a novel approach to enhance the ability of T cells against leukemia in donor lymphocytes infusion (DLI).

Methods: A hammerhead ribozyme targeting the Fas mRNA was synthesized and transfected into CTLL-2 cells by electroporation. Fas expression in CTLL-2 cells was detected by using RT-PCR, Western blot and flow cytometry, CTLL-2 cells viability was measured by MTT assay, caspase-3 proteolytic activity by caspase-3 detection kit, and cell apoptosis by flow cytometry.

[Study on the expression of hematopoietic growth factor gene in human umbilical vein endothelial cells using gene chip].

In order to detect the hematopoietic growth factor gene expressed in human umbilical vein endothelial cells using gene chip, human umbilical vein endothelial cells (ECV304) were cultured in vitro and divided into VEGF group and control group in same medium. 50 ng/ml hVEGF165 was added in the VEGF group. After culture for 24 hours all cells were collected for total RNA extraction.

Inhibition of Fas-mediated apoptosis in Yac-1 cell via Anti-Fas ribozyme.

To detect a new and more effective way against apoptosis mouse lymphomatic cell line Yac-1 in which fas gene was expressed highly was used as a model for studying the effects of anti-Fas ribozyme on Fas-mediated apoptosis. A hammerhead ribozyme gene targeting the fas mRNA was synthesized and its in vitro transcription vector was constructed, which was transfected into Yac-1 cells using electroporation. Rz596 expression was detected using RT-PCR, and Fas expression in Yac-1 cells was detected using RT-PCR, Western blot and flow cytometry.

Study on blocking the leukemia immune escape after BMT by Fas-Fas ligand pathway.

Background: To investigate if bone marrow transplantation (BMT) with bone marrow mononuclear cells (BMMCs) transducted with murine soluble Fas gene (sFas) using adenovirus vector could block the immune escape of leukemia cells eliminate the residual leukemia cells and reduce their relapse.

Methods: The recombinant adenovirus vector with murine sFas, adsFas, and the control vector adEGFP were constructed using homologous recombination between two plasmids in Escherichia coli. BMT was carried out after the BMMCs were infected with Adenoviruses.

[Role of apoptosis in cryoinjury of cord blood hematopoietic stem/progenitor cells and its mechanism].

To investigate the role and mechanism of apoptosis in cryoinjury of cord blood hematopoietic stem/progenitor cells, apoptosis of CD34(+) cells, mitochondrial membrane potential (MMP) and Fas antigen expression were detected by flow cytometry (FCM), the Bcl-2 protein expression was detected by immunohistochemistry, caspase-3 expression was determined by Western blot and caspase-3 activity analysis, colony-forming units (CFU) was performed by semi-solid methylcellulose culture. The results showed that when cells were store at -196 degrees C for 2 weeks or 4 weeks, apoptotic cells increased, gel electrophoresis displayed typical DNA ladder, and CFU decreased by 25.2% and 30.

[Study on blocking the tumor immune escape by Fas ligand pathway].

The expression of Fas ligand (FasL) on the membrane of many kinds of leukemia or solid tumor cells played an important role in the immune escape of tumor cells. This study was aimed to know if the soluble Fas (sFas), expressed by adenovirus, could block the immune escape of tumor cells by FasL pathway. The two recombinant adenoviral vectors, AdsFas with murine soluble Fas gene and AdEGFP with enhanced GFP protein gene, were constructed by homologous recombination between two plasmids in Escherichia coli with the AdEasy adenovirus vector system.

[Experimental study on blocking immune escape of leukemia cells in the recipient after bone marrow transplantation].

Objective: To investigate whether murine soluble Fas gene transfected marrow graft could block the immune escape of leukemia cells, so as to eliminate the residual leukemia cells and reduce relapse after bone marrow transplantation (BMT).

Methods: The murine leukemia/lymphoma models were established by inoculating female C57BL/6 mice (H-2b) with 10(5) EL4 cells/mouse through caudal vein. Donors of BM grafts were C57BL/6 male mice.

[FasL-cDNA transfected into mouse bone marrow cells ex vivo to prevent graft versus host disease].

To explore the new approach to prevent graft versus host disease (GVHD) by purging ex vivo T lymphocytes of bone marrow graft through Fas-FasL way, FasL-cDNA was transfected into BALB/c mouse bon e marrow cells by liposome ex vivo. The transfected cells were cultured together with BAC (BALB/c x C57BL/6) mouse bone marrow graft. The mixing bone marrow graft was infused into BALB/c mouse recipients after 60Co-gamma irradiation.

[A new method for construction of EGFP-labled recombinant adenovirus containing hVEGF(165) and its property in vitro].

By using AdEasy system, which is based on the homologous recombination in bacteria, an EGFP labled recombinant adenovirus vector containing hVEGF(165) was generated quickly and its property was studied in vitro. First, hVEGF(165) coding sequence was subcloned into the shuttle plasmid pAdTrack-CMV, then linearized and cotransferred with adenoviral backbone vector pAdEasy-1 into E. coli strain BJ(5183).