Iron overload as a risk factor for poor graft function following allogeneic hematopoietic stem cell transplantation.

Hematological malignancies are increasingly treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). Unfortunately, iron overload is a frequent adverse effect of allo-HSCT and is associated with poor prognosis. In the present study, we investigated hematopoiesis in iron-overloaded mice and elucidated the effects of iron overload on the bone marrow (BM) microenvironment. Iron-overloaded BALB/C mice were generated by injecting 20 mg/mL saccharated iron oxide intraperitoneally. Hematoxylin-eosin staining was performed to evaluate the effects of an iron overload in mice. BM cells obtained from C57BL/6 mice were transplanted into irradiated BALB/C mice (whole-body irradiation of 4 Gy, twice with a 4-hours interval) by tail vein injection. Two weeks after allo-HSCT, the hematopoietic reconstitution capacity was evaluated in recipients by colony-forming assays. Histopathological examinations showed brown-stained granular deposits, irregularly arranged lymphocytes in the liver tissues, and blue-stained blocks in the BM collected from mice received injections of high-dose saccharated iron oxide (20 mg/mL). Iron-overloaded mice showed more platelets, higher-hemoglobin (HGB) concentration, fewer granulocyte-macrophage colony-forming units (CFU-GM), erythrocyte colony-forming units (CFU-E), and mixed granulocyte/erythrocyte/monocyte/megakaryocyte colony-forming units (CFU-mix) than healthy mice. Iron-overloaded recipients presented with reduced erythrocytes and HGB concentration in peripheral blood, along with decreased marrow stroma cells, CFU-GM, CFU-E, and CFU-mix relative to healthy recipients. Taken together, our findings demonstrate that iron overload might alter the number of red blood cells after transplantation in mice by destroying the BM microenvironment, thereby affecting the recovery of BM hematopoietic function.

In vitro effects of reprogramming factors on the expressions of pluripotent genes and CD34 gene in human acute promyelocytic leukemia HL-60 cells.

OBJECTIVE: Our study aims to explore the in vitro effects of reprogramming factors on the expressions of pluripotent genes and CD34 gene in HL-60 cells. METHODS: According to the construction of lentiviral vector LV-OSCK of reprogramming factors (Oct-4, Sox2, Klf4, c-Myc), 293T cells were transfected to detect virus titer. The endogenous pluripotent genes (Oct4, SOX2, c-Myc and Klf4) and CD34 mRNA and protein expressions were detected by AP staining, immunofluorescence staining, qRT-PCR and flow cytometry. RESULTS: Expressions of Oct4, SOX2, c-Myc and Klf4 were 0.220±0.013, 0.186±0.009, 0.287±0.015 and 0.153±0.007. These levels were significantly higher in the experimental group than the control and blank groups. CD34 protein expression in the experimental group was also discovered to be significantly higher than the other two groups. CONCLUSION: The reprogramming factors could increase the expressions of pluripotent genes and CD34 gene in HL-60 cells.

Bone marrow-derived mesenchymal stem cells overexpressing MiR-21 efficiently repair myocardial damage in rats.

OBJECTIVE: We investigated the ability of bone marrow derived mesenchymal stem cells (BMSCs) overexpressing microRNA-21 (miR-21) to repair cardiac damage induced by anthracyclines in rats. METHODS: Sprague-Dawley (SD) rats of 2~3 weeks old were selected to isolate and culture BMSCs. A lentivirus harboring pLVX-miR-21 was generated and transfected into rat BMSCs. The rats were assigned into an untreated negative control group, and groups injected with adriamycin alone or with adriamycin followed by BMSCs, pLVX-BMSCs or pLVX-miR-21-BMSCs (n = 10 each). Proliferation and migration of cells were detected by cholecystokinin-8 (CCK- 8) and transwell. MiR-21 expression, mRNA expressions of B cell lymphoma 2 (Bcl2), BAX (BCL-2-associated X protein) and vascular endothelial growth factor (VEGF) were tested by qRT-PCR. Western blotting was applied to detect protein expressions of Bcl-2, Bax and VEGF. RESULTS: Using CCK- 8 and transwell assays, we found that pLVX-miR-21-BMSCs, which overexpressed miR-21, exhibited greater proliferation and migration than untransfected BMSCs or pLVX-BMSCs. Ultrasonic cardiograms and immunohistochemical analysis demonstrated that among the five groups, the pLVX-miR-21-BMSC group exhibited the most improved heart function and enhanced angiogenesis. Moreover, the pLVX-miR-21-BMSC group showed enhanced expression of Bcl-2, VEGF and Cx43 and reduced expression of Bax, BNP and troponin T. CONCLUSION: These findings suggest miR-21 overexpression enhanced the proliferation, invasiveness and differentiation of BMSCs as well as expression of key factors (Bcl-2, VEGF and Bax) essential for repairing the cardiac damage induced by anthracyclines and restoring heart function.

The Construction and Identification of Induced Pluripotent Stem Cells Derived from Acute Myelogenous Leukemia Cells.

OBJECTIVE: The present study aimed to establish an induced pluripotent stem cell (iPSC) line from acute myelogenous leukemia (AML) cells in vitro and identify their biological characteristics. METHODS: Cells from the AML-infiltrated skin from an M6 patient were infected with a lentivirus carrying OCT4, SOX2, KLF4 and C-MYC to induce iPSCs. The characteristics of the iPSCs were confirmed by alkaline phosphatase (ALP) staining. The proliferation ability of iPSCs was detected with a CCK-8 assay. The expression of pluripotency markers was measured by immunostaining, and the expression of stem cell-related genes was detected by qRT-PCR; distortion during the induction process was detected by karyotype analysis; the differentiation potential of iPSCs was determined by embryoid body-formation and teratoma-formation assays. ALP staining confirmed that these cells exhibited positive staining and had the characteristics of iPSCs. RESULTS: The CCK-8 assay showed that the iPSCs had the ability to proliferate. Immunostaining demonstrated that iPSC clones showed positive expression of NANOG, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. qRT-PCR results revealed that the mRNA expression of Nanog, Lin28, Cripto, FOX3, DNMT3b, DPPA2, and DPPA4 significantly increased in iPSCs. Karyotype analysis found no chromosome aberration in the iPSCs. The results of the embryoid body-formation and teratoma-formation assays indicated that the iPSCs had the potential to differentiate into all three germ layers. CONCLUSION: Our study provided evidence that an iPSC line derived from AML cells was successfully established.

Constitutive activation of NF-κB signaling by NOTCH1 mutations in chronic lymphocytic leukemia.

NOTCH1 mutations occur in approximately 10% of patients with chronic lymphocytic leukemia (CLL). However, the relationship between the genetic aberrations and tumor cell drug resistance or disease progression remains unclear. Frameshift deletions were detected by gene sequencing in the NOTCH1 PEST domain in three naive CLL patients. These mutations were associated with chromosomal abnormalities including trisomy 12 or 13q deletion. Of note, one of the patients developed Richter's transformation during FCR treatment. Immunofluorescent and western blot analyses revealed a markedly higher intracellular domain of NOTCH (ICN) expression in the mutated cells compared with their unmutated counterparts and normal CD19+ B lymphocytes (P<0.01 and P<0.001, respectively). In addition, strong DNA-κB binding activities were observed in the mutant cells by gel shift assays. RT-PCR analysis revealed elevated RelA mRNA expression in the mutant cells, while RelB levels were variable. Reduced levels of RelA and RelB mRNA were observed in unmutated CLL and normal B cells. Compared to unmutated CLL and normal B cells, increased apoptosis occurred in the mutant cells in the presence of GSI (ICN inhibitor) and PDTC (NF-κB inhibitor), particularly under the synergistic effects of the two drugs (P=0.03). Moreover, IKKα and IKKß, the active components in the NF-κB pathway, were markedly inhibited following prolonged treatment with GSI and PDTC. These results suggested that NOTCH1 mutations constitutively activate the NF-κB signaling pathway in CLL, which is likely related to ICN overexpression, indicating NOTCH1 and NF-κB as potential therapeutic targets in the treatment of CLL.

Adverse drug interactions as a high-risk factor for lethal post-transplant complications in Chinese population.

Metabolism of triazole antifungal agents is highly competitive to conventional post-transplant immunosuppressants like cyclosporine A (CsA) via the cytochrome P450-dependent pathway. We present the first report on lethal complications that may arise due to this type of drug interaction. A retrospective survey identified 10 of 104 cases (9.62%) that suffered life-threatening complications associated with the interaction between CsA and itraconazole or voriconazole following allogeneic hematopoietic stem cell transplantation (allo-HSCT) at our center. According to the close drug monitoring, all 10 patients experienced supratherapeutic levels of CsA even with a preemptive CsA dosage reduction and prompt dose adjustment. Six patients developed grade I to III acute graft-versus-host disease (aGVHD) and eventually died from either idiopathic pneumonia syndrome or diffuse alveolar hemorrhage; another four patients died from CSA-associated neurological complications. Impaired hepatic and renal function was noted in only one of these 10 cases. The high frequency as well as the unpredictability of severe complications lead us to suggest that triazole should always be replaced by another antifungal medication (e.g., amphotericin B or Echincandins) while patients receive CsA after HSCT, especially in the Chinese population.

A novel nonradioactive CFDA assay to monitor the cellular immune response in myeloid leukemia.

BACKGROUND: Donor lymphocyte transfusion (DLT) may induce the graft-versus-leukemia (GVL) effect for patients with AML relapsed after transplant. However, AML is a highly diverse disease and the limited overall efficacy of DLT in clinical practice emphasizes the importance of identifying a specific subgroup of patients who might benefit from this treatment approach. OBJECTIVE: To monitor the cellular immune response after DLT, we developed an active specific immunization strategy using in vitro generated AML-trained T cells to induce a highly specific antileukemic T-cell response and thus established a novel nonradioactive assay system to assess the antileukemia immunity by flow cytometry, correlated with [3H]-thymidine uptake. METHODS: The myeloid blasts derived from five patients with AML relapsed post-allogeneic hematopoietic stem cell transplantation (allo-HSCT) were first labeled with CFDA (5,6-carboxyfluorescein diacetate succinimidyl ester). To analyze the growth inhibitory potential of the donor T cells trained by AML progenitor cells, the myeloid blasts were induced to proliferate by means of a cytokine cocktail (50ng/mL of SCF; 25ng/mL of IL-3; 100ng/mL of GM-CSF; 100ng/mL of G-CSF; 2U/mL of EPO; 0.47g/L of transferrin; and 5×10(-5)mmol/L of 2-ME). The T cell mediated growth inhibitory potential was detected after 5 days by flow cytometry and correlated with [3H]-thymidine uptake. The simultaneous use of TO-PRO-dye and calibrate beads allowed not only the cell viability to be known but also allowed quantification of the effector function. RESULTS: Here, we applied a CFDA dye to track the proliferation and expansion of AML blasts in response to the cytokine cocktail in vitro. AML-trained T cells, expressed high levels of the activation markers CD25 and CD69, and were generated to recognize the leukemic progenitor cells and inhibit cytokine-induced leukemic cell proliferation, which is an active specific immunization strategy circumventing the identification of leukemia-associated antigens. The capability of proliferation inhibition of AML-trained T cells evaluated with our nonradioactive, CFDA-based assay provided comparable results with the classic [3H]-thymidine assay with an even lower ratio of effector to target cells. CONCLUSION: Taken together, the novel, nonradioactive, CFDA-based assay was a robust tool to monitor the antileukemic immune response after DLT in myeloid leukemias.

[Clinical study of umbilical cord-derived mesenchymal stem cells for treatment of nineteen patients with steroid-resistant severe acute graft-versus-host disease].

OBJECTIVE: To evaluate the safety and efficacy of umbilical cord-derived mesenchymal stem cells (MSCs) infusion in patients with steroid-resistant severe acute graft-versus-host disease (aGVHD). METHODS: A total of 19 patients with steroid-resistant severe aGVHD received MSCs infusion treatment. The treatment response, transplantation-related mortality, events associated with infusion and relapse rate were analyzed. RESULTS: Two patients with grade II, 5 patients with grade III and 12 patients with grade IV aGVHD received a total of 58 infusions of MSCs. The mean total dose of MSCs was 2.13 (range 0.60 - 7.20)×10(6) cells per kg bodyweight. Seven patients received one infusion, 2 patients received two infusions, and 10 patients received three or more infusions. Eleven patients had a complete response and 4 had a partial response and 4 had no response. No patients had side-effects during or immediately after infusions, and no MSCs related tumorigenesis was detected to date. Eleven patients survived and 8 died, 4 for aGVHD, 1 for infection and 2 for aGVHD with concomitant infection and 1 for underlying leukemia relapse. The cell viability of freshly prepared MSCs is 93% (92% - 95%) by trypan blue staining. The cell viability of programmatically frozen and thawed MSCs is 72% (70% - 74%). CONCLUSION: Infusion of umbilical cord-derived MSCs expanded in vitro is an effective therapy for patients with steroid-resistant severe aGVHD without negative impact on relapse. Freshly prepared MSCs are superior to frozen and thawed cells in terms of cell viability.

[Clinical analysis on 40 patients with chronic lymphocytic leukemia].

This study was aimed to analyze the clinical and laboratorial characteristics of patients with chronic lymphocytic leukemia (CLL), as well as their relationship with outcomes of patients. The clinical and laboratorial data of 40 CLL patients admitted from 2004 to 2010 in our hospital were analyzed retrospectively. The results indicated that the most of CLL attacked the elderly male patients with median age 66 (from 42 to 80). Flow cytometric analysis showed that 25 cases were positive for typical immunophenotype of CLL. On the other hand, all the patients clearly expressed CD19 and CD5, 7 cases (17.5%) and 14 cases (35%) were positive for the expression of CD38 and Zap70 respectively. 8 cases harbored a mutated immunoglobulin heavy-chain (VH) gene, among them 4 cases belong to VH3 family. Interphase FISH analysis showed that P53 deletion, RB1 deletion, trisomy 12 and normal chromosome were detected in 6, 3, 1, and 5 cases, respectively. The median PFS in 31 patients received treatment of fludarabine based chemotherapy was 48 months (95%CI: 39 - 57 months), among them 27 cases (87.1%) achieved CR + PR. While PFS was 14 months (95%CI: 10 - 18 months, P < 0.001) in 9 patients received other treatment regimen, out of them only 3 cases (33.3%) achieved CR + PR. Patients with normal level of serum ß2-microglobulin at diagnosis showed significantly higher overall survival (78%, 95%CI: 69% - 87%) in 36 months than those with abnormal level of serum ß2-microglobulin (47%, 95%CI: 35% - 59%, P = 0.004). Significant difference in the rate of CR + PR was noted in the Zap70 positive group (50%) and in negative group (88.5%, P = 0.006). All of 8 patients with IgVH mutation displayed CR after treatment, while 4 cases (66.7%) archived CR among 6 patients without IgVH mutation. It is concluded that CLL is characterized by high heterogeneity in both clinical features and molecular markers, which are associated with prediction of outcomes for patients. The treatment with fludarabine-based chemotherapy results in a major benefit and long survival for patients with CLL.

[A case of Richter syndrome transformed from chronic lymphocytic leukemia with karyotype aberration of trisomy 12].

This study was aimed to investigate the relationship between Richter's syndrome (RS) transformation and clinical characteristics as well as karyotype of patient with chronic lymphocytic leukemia (CLL). By the follow-up of a patient with CLL, the clinical characteristics, karyotype, treatment pattern and its effect, as well as disease progression were monitored regularly with serological test, flow cytometry and FISH technique. The results indicated that the patient typically presented with history of CLL at initial diagnosis, with expression of CD5(+), CD19(+) and CD23(+), Binet stage C, as well as karyotype aberration of trisomy 12, and poorly responded to 4 cycles of standard chemotherapy of FCR regimen. The disease progression was confirmed at 5 months with the symptoms of fever in the absence of infection, elevated lactate dehydrogenase level and rapidly enlarging lymphnodes which showed typically diffuse large B cell lymphoma by the biopsy. It is concluded that karyotype aberration of trisomy 12 is one of the risk factors for RS transformation, and treatment pattern of the patient with CLL may be associated with the transformation of RS.

[Homing characteristics of graft cells in leukemia mice after allogenic bone marrow transplantation with different conditioning regimens].

The aim of this study was to investigate the homing characteristics of bone marrow cells in leukemia mice after allogenic bone marrow transplantation with different conditioning regimens on the basis of a leukemia mouse model. Allogenic bone marrow transplantation was performed after three different kinds of conditioning regimen, including nonmyeloablative conditioning regimen (5 Gy (60)Co γ ray total body irradiation, A group), radiotherapeutic myeloablative conditioning regimen (9 Gy (60)Co γ ray total body irradiation, B group) and chemotherapeutic myeloablative conditioning regimen (large dose chemotherapy, C group). In the recipient mice, the nucleated cell number in peripheral blood, bone marrow and spleen was counted, the percentage of positive cells capable of connecting with FITC labeled anti-mouse H-2K(b) antibody was detected by flow cytometry and the homing ratio in bone marrow and spleen was calculated at 24, 48, 72, 96 h after bone marrow transplantation. The results showed that donor myeloid cells displayed homing and then mobilization (going out of home) in group A; homing, mobilization, and rehoming in group B and C, and there was a little delay of homing in the spleen in group C. In bone marrow, the homing efficiency of A group was the highest in early period and the lowest [(0.90 ± 0.09)%] in the fourth day with the mobilization of myeloid cells (P < 0.05), and the homing efficiency of B and C groups was lower in the early period and the highest [(2.17 ± 0.26)%, B group] in the fourth day with the rehoming of myeloid cells (P < 0.05). In spleen, the homing efficiency was similar to that in bone marrow and there still was a little delay in C group. It is concluded that the homing ratio is high in the early period and decrease obviously in 72 h after bone marrow of leukemia mice treated with nonmyeloablative conditioning regimen. The homing ratio is low in the early period and increases obviously in 72 h after bone marrow of leukemia mice treated with radio-or chemotherapeutic myeloablative conditioning regimens. The homing ratio does not obviously change between the early period and 72 h after bone marrow of leukemia mice treated with chemotherapeutic myeloablative conditioning regimen, and lies between group A and B.

[Comparison of the biological characteristics of serum-free and fetal bovine serum-contained medium cultured umbilical cord-derived mesenchymal stem cells].

OBJECTIVE: To compare the differences of biological characteristics between human umbilical cord-derived mesenchymal stem cells (UC-MSCs) cultured by serum-free medium or fetal bovine serum-contained complete medium to establish a xenogeneic protein-free UC-MSCs culture system. METHODS: Healthy human umbilical cord segments were digested with collagenase. UC-MSCs were cultured by serum-free MesenCult-XF medium and FBS-based αMEM complete medium, then analyzed the morphology, immunophenotype, expansion potential, lineage differentiation potential, karyotype and immunosuppression of early passages. RESULTS: The average cell diameters of UC-MSCs in suspension cultured by serum-free medium and FBS-based medium were 26 (18 - 39) µm and 35 (20 - 61) µm, respectively. Cell expansion folds with serum free medium and FBS-based medium were (5.2 ± 0.2) and (3.5 ± 0.1) respectively, in the first five passages. The expansion potential of serum-free medium cultured UC-MSCs was significantly higher than FBS-based medium cultured ones (P < 0.05). A panel of markers CD29, CD44, CD90, CD73, CD105 and HLA-ABC expressed on human UC-MSCs. Hematopoietic lineage markers CD34, CD45 and HLA-DR were not detectable on UC-MSCs. The cpm were (4.57 ± 0.14)×10(4), (2.04 ± 0.16)×10(4) and (0.42 ± 0.04)×10(4), respectively when serum-free medium cultured MSCs were added to the cultures at MSCs/T cell ratios of 1:100, 1:10 and 1:5. While the cpm was (4.57 ± 0.14)×10(4), (2.04 ± 0.16)×10(4) and (0.42 ± 0.04)×10(4), respectively when serum-free medium cultured UC-MSCs were added to the cultures. The immunosuppressive potential of serum-free medium-cultured UC-MSCs was higher than serum-contained medium cultured ones at three different MSC/T cell ratios (P < 0.05). CONCLUSION: Compare with serum-contained medium cultured early passages of UC-MSCs, the cell diameter of serum-free medium cultured UC-MSCs was smaller with higher expansion potential. No xenogeneic proteins were presented in UC-MSCs preparations when cultured with serum-free medium. Human UC-MSCs suppressed T-cell proliferation in a dose-dependent manner. The immunosuppressive potential of serum-free medium cultured UC-MSCs was higher than FBS-based medium cultured ones.

[Apoptosis-inducing effect of C-MYC siRNA on acute lymphoblastic leukemia Jurkat cell line].

The study was purposed to investigate the effects of C-MYC siRNA on the proliferation and apoptosis of acute lymphoblastic Jurkat cell line. siRNA targeting the site 1545-1565 of C-MYC mRNA was designed and chemically synthesized, then C-MYC siRNA was transfected into Jurkat cells by the transfer agent (HiPerFect Transfection Reagent), the morphological changes were observed under inverted microscope; the tetrazole compound (MTS) was applied to draw the cell growth curve; the cell colony test was used to detect the effect of C-MYC siRNA on the proliferation of Jurkat cells; the flow cytometry and TUNEL method were used to analyze the apoptosis of Jurkat cells. The results showed that after Jurkat cells were treated with different concentrations of C-MYC siRNA, the growth of Jurkat cells was inhibited to various degrees, inhibitory rate was enhanced as C-MYC siRNA concentration increased. C-MYC siRNA also could obviously inhibit the cell clony formation. The apoptosis of cells could be detected by flow cytometry and TUNEL method, the apoptosis rate of cells increased along with prolonging of treatment with C-MYC siRNA. It is concluded that the chemically synthesized C-MYC siRNA can inhibit significantly the proliferation and induce the apoptosis of Jurkat cells.

[Effects of small interference RNA against c-myc on expression of c-myc and h-tert genes in acute lymphoblastic leukemia cell line Jurkat].

This study was purposed to investigate the effect of small interfering RNA against c-myc on c-myc, h-tert gene and protein expressions in acute lymphoblastic leukemia cell line (Jurkat cells), so as to provide new methods and targets for gene therapy of leukemia. The siRNA against target sites 1545-1565 of c-myc mRNA was chemically synthesized and was transfected into Jurkat cells by transfectant. The c-myc, h-tert mRNA and protein expression levels before and after treatment with c-myc siRNA were detected by RT-PCR and Western blot, respectively. The results showed that c-myc siRNA obviously inhibited the proliferation of Jurkat cells, the half inhibitory concentration (IC50) for 48 hours was about 75 nmol/L. c-myc siRNA could decrease c-myc, h-tert mRNA and C-MYC, h-TERT protein expression levels of Jurkat cells. It is concluded that c-myc siRNA significantly reduce c-myc, h-tert mRNA and protein expression levels through inhibiting c-myc mRNA expression and decreasing intracellular level of C-MYC protein.

[Calcium ionophore induces the differentiation of chronic myeloid leukemia cells into dendritic cells].

The aim of this study was to investigate the ability of calcium ionophore (CI ) to induce the differentiation of CML cells into dendritic cells (DC), to analyze the P210 expression in DCs and to evaluate the stimulatory effect of CML-DC on production of cytotoxic activity against CML cells via activating the autologous T cells. The mononuclear cells were isolated from bone marrow of CML patients whose WBC counts were more than 30x10(9)/L when samples were collected, then the lymphocytes and monocytes were discarded by pouring out supernatant twice at different culture time point. Slightly adherent cells were cultured in RPMI 1640 containing 10% FCS, with or without CI (375 ng/ml) and GM-CSF (200 ng/ml) at 37 degrees C, 5% CO2, fully humidified atmosphere for 96 hours. The cell morphology was observed under the inverted microscope and electron microscope; the expression of CD antigens was analyzed with flow cytometry; the P210 expression was measured with Western blot. LDH assay was used to evaluate the effect of cultured CML cells (CML-DC) generating cytotoxic T lymphocyte (CTL) activity against CML cells. The results indicated that after treatment with calcium ionophore and GM-CSF for 96 hours, CML cells showed DC morphological characteristics under inverted microscope and electron microscope. The expression of CD83, CD86, CD40, CD80 and HLA-DR increased remarkably. P210 was expressed in the CML-DC, but the expression level was lower than that in CML cells without CI and GM-CSF treatment. LDH assay showed that the CTL activity against CML was found greater in autologous T cells activated by CML-DC than that by CML cells. It is concluded that the CML cells can be induced to quickly differentiate into DC when cultured with CI and GM-CSF. CML-DC expresses P210, but the expression level is lower than that in CML cells. CML-DC can stimulate autologous T cells to produce CTL against CML.

[Apoptosis of human myeloid leukemia cell line HL-60 cells induced by siRNA targeting gene c-myc].

This study was purposed to investigate the effects of siRNA targeting c-myc on apoptosis induction, proliferation in inhibition as well as c-myc protein and mRNA expression in human myeloid leukemia cell line HL-60 cells. C-myc siRNA synthesized in vitro was transfected into HL-60 cells by liposome. Changes of cell morphology were observed. Growth inhibition was detected by MTT assay and colony formation assay, and cell apoptosis was determined by DNA ladder. The expressions of c-myc mRNA and protein were detected by RT-PCR and Western-blot respectively. The results indicated that c-myc siRNA remarkably inhibited the cell proliferation, with an IC(50) value of 150 nmol/L. Data of DNA ladder showed that HL-60 cells apoptosis could be efficiently induced by c-myc siRNA, the apoptosis rate positively correlated with the time duration of treatment with drugs. The c-myc mRNA and protein expressions on HL-60 cells decreased after treatment with c-myc siRNA, which negatively correlated with time duration of treatment. It is concluded that c-myc siRNA can efficiently induce growth inhibition, decrease the expressions of c-myc mRNA and protein, and induce apoptosis in HL-60 cells.

In vitro inducing effect of dendritic cells cotransfected with survivin and granulocyte-macrophage colony-stimulating factor on cytotoxic T cell to kill leukemic cells.

BACKGROUND: Survivin is a rather specific gene in tumor tissue. We transfected dendritic cells (DCs) with recombinant adenovirus (Ad) containing survivin gene and granulocyte-macrophage colony-stimulating factor (GM-CSF) gene and tested the inducing effect of the transfected DCs on cytotoxic T lymphocytes (CTL) to kill leukemic cells. METHODS: After derived from the peripheral, DCs was assayed by mixed leukocyte reaction (MLR) tests. Lactate dehydrogenase (LDH) release test was used to evaluate cytotoxicity of CTL. RESULTS: Expression of survivin in transfected DCs was confirmed by Western blotting analysis. GM-CSF expression was confirmed by enzyme-linked immunosorbent assay (ELISA). In MLR assay, DCs coinfected with Ad-survivin and Ad-GM-CSF induced higher allogeneic lymphocyte reaction than control DCs at ratios of 1:5, 1:10, 1:50 and 1:100. DCs coinfected with Ad-survivin and Ad-GM-CSF had much higher activity of CTL to HL-60 cells than DCs infected with Ad-survivin only, Ad-GM-CSF only, or control DCs. Levels of interleukin-12 (IL-12) and interferon gamma (IFN-gamma) in lymphocyte supernatants containing DCs coinfected with Ad-survivin and Ad-GM-CSF were significantly higher than those in the control group. CONCLUSION: DCs coinfected with Ad-survivin and Ad-GM-CSF induce much higher anti-leukemic response in vitro than those infected with either factor. Therefore, adenovirus vectors containing survivin and GM-CSF genes may be promising vaccine candidates for leukemia therapy.

[Demethylation and transcription of p16 gene in malignant lymphoma cell line CA46 induced by EGCG].

The study was purposed to investigate the possible mechanism of epigallocatechin-3-gallate (EGCG) induced p16 gene demethylation and transcription regulation in the malignant lymphoma cell line-CA46. The induced growth inhibition of CA46 cells was assayed by growth curve and MTT; the DNA content of CA46 cells was analyzed by flow cytometry after being exposed to EGCG; the methylation status of the p16 gene in CA46 cell line before and after treatment with EGCG was detected by the nested-methylation specific PCR and DNA sequencing; the mRNA of p16 and DNA methyltransferases (DNMT3A and DNMT3B) gene were determined by RT-PCR. The results showed that in comparison with the control, all the 3 different concentration of EGCG were able to inhibit the growth of malignancy cell lines and increase the cell number in G(0)/G(1) phase. After treatment with EGCG for 48 hours, the methylation level was apparently attenuated in a concentration-dependent manner. Expression of p16 gene in untreated group was mild while in the treated groups it had been greatly strengthened, as compared with untreated group, the gray scale ratio of p16 to beta-actin 1 treated with EGCG (6, 12, 24) microg/ml was increased from (0.05 +/- 0. 01) to (0.19 +/- 0.03), (0.39 +/- 0.10), (0.85 +/- 0.09) respectively, exhibiting a significant difference (p < 0.05); as compared with the untreated group, after treatment with EGCG for 48 hours, the expressions of DNMT3A and DNMT3B were obviously down-regulated. It is concluded that EGCG can activate and up-regulate the expression of p16 gene mRNA which inhibits the proliferation of CA46 cell through inducing the G(0)/G(1) arrest by demethylation and/or by inhibiting DNMT3A and DNMT3B gene.

[Induction of anti-lymphoma cytotoxic T cell effect by dendritic cells transfected with recombinant adenovirus vectors carrying survivin gene].

This study was purposed to investigate the immunological effects of modified dendritic cells (DCs) in inducing cytotoxic T cells (CTLs) effect against lymphoma cells. The DCs were derived from human peripheral blood and transfected with recombined adenovirus vector carrying survivin gene, Western blot was used to detect the expression of survivin, the lactate dehydrogenase (LDH) release test was used to determine the cytotoxicity of CTLs, the mixed lymphocyte reaction (MLR) was used to measure the ability to proleferate allo-lymphocyte by DCs, ELISA was used to assay IL-12 level in supernatant. The results showed that the expression of survivin in transfected dentritic cells was confirmed by Western blot analysis. In MLR assay, DCs transfected with Ad-survivin could induce higher allogeneic lymphocytes reaction at the ratios of 1:5, 1:10, 1:50 and 1:100. DCs transfected with Ad-survivin had much higher activity of CTL to CA46 cells than control DCs. The levels of IL-12 of supernatants containing DCs transfected with Ad-survivin were significantly higher than that in the control group. It is concluded that DCs transfected with Ad-survivin can induce CTL response in vitro against lymphoma cells.