Therapeutic effect of focal adhesion kinase gene silence on leukemia / 中国实验血液学杂志

This study was aimed to investigate the effects of focal adhesion kinase (FAK) gene silence on leukemia cell growth, leukemogenesis and efficacy of chemotherapy drug. Vector containing lentiviral-FAK-shRNA was constructed and transfected into BCR/ABL-BaF3 leukemic cells, the cell growth and apoptosis were detected in vitro. The effect of FAK shRNA on leukemogenesis was studied in a murine model with leukemia. The apoptosis of leukemia cells and survival of leukemic mice treated by FAK shRNA combined with drug STI571 were monitored. The results showed that FAK gene expression was knocked down by lentiviral-FAK-shRNA. FAK gene silencing inhibited leukemia cell growth in vitro. The apoptosis test results showed that the percentages of Annexin V(+) cells in vector control group and FAK shRNA group were (3.46 ± 0.56)% and (7.3 ± 0.79)%, respectively, and the difference was statistically significant (p < 0.05). The mice in vector control group died at day 21 to 27, while the mice in FAK shRNA group died between day 52 and 60, and the difference was statistically significant (p < 0.05). Moreover, FAK gene silence combined with drug STI571 could enhance the apoptosis of leukemia cells and prolong survival time of leukemic mice. It is concluded that FAK gene silence inhibits leukemogenesis and promotes efficacy of chemotherapy drug on leukemia cells, indicating FAK gene silence may be considered as a new therapeutic strategy for leukemia.

Biphasic effect of TIMP-2 on the growth of leukemic SHI-1 cells in nude mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the influence of tissue inhibitor of metalloproteinase 2 (TIMP-2) on the infiltrative patterns of human monocytic leukemic cell line SHI-1 in nude mice.</p><p><b>METHODS</b>1) 1 x 10(7) TIMP-2 gene transduced SHI-1 (SHI-1-TIMP-2) and SHI-1 transduced MSCV gene (SHI-1-MSCV) cells were inoculated via tail vein into 6-week nude mice, which pretreated by splenectomy, cytoxan intraperitoneal injection, and sublethal irradiation(referred as SCI nude mice). 30 days after inoculation, half of the mice were sacrificed, and the infiltration patterns were investigated by histological exam and human CD45 immunohistochemistry, other mice were observed for survival time. 2) Leukemic cells inoculated subcutaneously into the axillary area of mice without any pre-treatment. On day 23 and 30, mice were sacrificed to measure the volume of neoplasm. TIMP-2 protein expression and the micro vein density were detected by immunohistochemistry.</p><p><b>RESULTS</b>In SCI nude mice inoculated via caudal vein with SHI-1-TIMP-2 cells, the survival time was shorter and infiltration (including in central nervous system) was higher than that in those inoculated with SHI-1-MSCV cells. However, in inoculated subcutaneously group, the neoplasm though grew rapidly at first, over expression of TIMP-2 limited the tumor growth and angiogenesis.</p><p><b>CONCLUSION</b>The functions of TIMP-2 are diversity; the role of TIMP-2 in tumor infiltration and metastasis was worthy of further investigation.</p>

Effects of NKG2D and its ligands RAE-1 and H60 on graft-versus-tumor response / 中国实验血液学杂志

The study was purposed to explore the effects of NKG2D receptor and its ligands RAE-1 and H60 on graft-versus-tumor (GVT) response induced by MHC haploidentical bone marrow/spleen cell transplantation. Female (BALB/c x C57BL/6) F1 mice (CB6F1, H-2K(b/d)) inoculated with H22 cells to develop a solid tumor model were the recipients, and bone marrow mixed with spleen cells of the healthy male C57BL/6 (H-2K(b)) mice were the donor cells. GVT response was observed after transplantation that from donor cells T and NK cells were purged with anti-CD3 and anti-NK monoclonal antibody, and the NKG2D receptor was blocked with anti-NKG2D monoclonal antibody, the expression levels of RAE-1 and H60 mRNA in tumor tissue were measured by means of semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) at different time points after transplantation. The results showed that the GVT response of transplantation was reduced after in vitro depletion of T and NK cells or blocking NKG2D receptor in donor cells of the graft, the expression levels of RAE-1 and H60 mRNA in tumor tissue increased after transplantation of haploidential bone marrow mixed with spleen cells. It is concluded that NKG2D and its ligands RAE-1 and H60 may play important roles in GVT response.

HB-1, an acute myeloid leukemic cell line with the capability of infiltrating into the brain in CBA/N mice / 生理学报

An acute myeloid leukemic HB-1 cell line was cloned and established from the spleen cells of irradiated CBA/N mice. Acute myeloma leukemia-like syndrome would be induced in normal CBA/N mice after intravenous injection of HB-1 cells, and the death of mouse happened within about two weeks. In general, leukemic cells transplanted into the mice would infiltrate into the hematopoietic organs, lungs, kidneys and liver. An interesting observation in our study was that HB-1 cells were present not only in the lung, kidney, and liver but also in the cerebrum and cerebellum. It was beyond our expectation that the leukemic cells could go through the blood-brain barrier in most circumstances. On the basis of the observation, we expect that HB-1 cells could be used as a very useful model to elucidate the mechanism of infiltrating the blood-brain barrier for certain type of cells.

STI571 combined with vincristine greatly suppressed the tumor formation of multidrug-resistant K562 cells in a human-nude mice xenograft model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The development of the targeted signal transduction inhibitor STI571 has prompted us to treat chronic myeloid leukemia in different ways. Since STI571 may reverse multidrug-resistance of K562/MDR cells in vitro, we studied the effect of STI571 on multidrug-resistant K562 cells in vivo.</p><p><b>METHODS</b>Multidrug-resistant human leukemia cell line K562-n/VCR expresses both bcr/abl fusion gene and multi-drug resistance (mdr1) gene. It is a vincristine resistant cell line subcloned from the vincristine (VCR) sensitive cell line K562-n induced by vincristine in vitro. K562-n and K562-n/VCR cells were inoculated subcutaneously into both sides of nude mice breast (5 x 106 cells/each) to establish a human leukemia xenograft model. The incidence and volume of tumor were observed. In the tumor-bearing nude mice, anti-tumor drugs vincristine, daunorubicin (DNR), STI571, and STI571 plus VCR for the treatment of mdr1 and bcr/abl double positive leukemia were studied respectively.</p><p><b>RESULTS</b>The tumor incidence was 100% in the nude mice inoculated with either K562-n or K562-n/VCR. The transcription of the mdr1 gene and expression of P-gp were negative in K562-n cells but positive in K562-n/VCR cells. The intracellular accumulation of DNR in K562-n cells was higher than that in K562-n/VCR cells (P < 0.05). The tumor incidence of K562-n/VCR cells in nude mice was much higher than that of K562-n cells in chemotherapy groups, and the mean volume of the tumors was also larger (P < 0.05). STI571 combined with VCR significantly suppressed the proliferation of K562-n/VCR cells.</p><p><b>CONCLUSIONS</b>The MDR characteristics of K562-n/VCR in vivo were the same as in vitro. STI571 had a significant tumor-suppressing effect on VCR-sensitive leukemia cells and a moderate effect on MDR leukemia cells. VCR combined with STI571 had an excellent tumor-suppressing effect on both K562-n/VCR and K562-n in the human-nude mice xenograft model.</p>

Experimental study on immunotherapy with dendritic cell in leukemic mice model / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the feasibility and efficiency of immunotherapy with dendritic cell (DC) in leukemic mice model after allogeneic bone marrow transplantation (allo-BMT).</p><p><b>METHODS</b>Mature 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.</p><p><b>RESULTS</b>Mature 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).</p><p><b>CONCLUSION</b>Immunotherapy 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.</p>

Growth and infiltration of human monocytic leukemia cell in nude mice: a model for central nervous system leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To establish a model of human monocytic leukemia with CNS infiltration in BALB/c nude mice.</p><p><b>METHODS</b>BALB/c nu/nu mice pre-treated by splenectomy, cytoxan intraperitoneal injection, and sublethal irradiation (SCI), were transplanted intravenously with 1 x 10(7) of human monocytic leukemic SHI-1 cells. The leukemic cells engrafted in the mice were detected by RT-PCR, histopathological examination, immunohistochemistry and FCM.</p><p><b>RESULTS</b>The survival time of SCI-nu/nu mice was 33-46 d. Paraplegia occurred in some of the mice. 5 weeks after transplantation, SHI-1 cells engrafted in SCI-nu/nu mice, multi-organs were involved and green solid neoplasms were formed in some organs. Histopathological examination found that SHI-1 cells infiltrated in liver, lung, kidney and testis of the mice and vertebral and skull bone marrow was replaced by leukemic cells. Leukemic cell penetrated through the surface of vertebrae, formed neoplasm, and entered the subdural space, but seldom involved the spinal parenchyma. In brain leukemia cells were filled in the subdural space and pia-arachnoid, covered the surface of cerebrum, cerebellum, spread along the virchow-robin space on the surface of pia mater, and eventually invaded the brain parenchyma.</p><p><b>CONCLUSION</b>SHI-1 cells could engrafted in the SCI-nu/nu mice, form an efficient and reproducible experimental model of CNSL and systematic leukemia. This model may be useful for studying the pathogenesis of CNSL.</p>

Anti-leukemia immunity induced by dendritic cells fused with L615 tumor cells / 中国实验血液学杂志

This study was aimed to investigate the specific anti-L615 leukemia cell immunity induced by L615/DC fused cell vaccine in vivo and in vitro. BM-derived DCs were generated from bone marrow of 615 mice by culturing for 9 - 10 days in culture medium supplemented with GM-CSF and IL-4. Irradiated L615 tumor cells were fused with DC by using PEG to form fused cell vaccine, with which 615 mice were immunized. After immunization, the specific proliferation ability and cytotoxicity against L615 leukemia cells in vitro were examined by MTT and LDH methods. Anti-leukemia effect of fused cell vaccine in vivo was studied by observing the immunotherapy effects on L615 tumor-bearing mice. The results showed that fully mature and functional bone marrow-derived DC were obtained. L615/DC fused cell vaccine could elicit potent specific proliferation response of spleen T cells from immunized mice when contacting with the same antigen at the second time, and could also elicit the effective cytotoxic activity against L615 leukemia cells in vitro, which were significantly different from other groups. In vivo the average survival time of the tumor-bearing mice received immunotherapy with L615/DC fused cell vaccine was 25.7 +/- 1 days, and one fourth of treated tumor-bearing mice survived for long time, but the mice of control group died all, their average of survival time was 17.5 +/- 1 days. The immunized mice survived with no evidence of recurrence when exposed to the second attack of lethal dose of living L615 cells 2 months later. It is concluded that L615/DC fused cell vaccine can improve the immunogenecity of L615 and induce effectively the specific anti-leukemia immunity against L615 leukemia cells to eliminate the residual leukemia cells, prolong the survival time and induce the immune memory to avoid the relapse. Thus, the fused cell vaccine may be an attractive strategy for malignance immunotherapy.

Establishment and characterization of a human acute monocytic leukemic cell line, SHI-1, carrying t(6;11)(q27;23) and p53 gene alteration / 中华血液学杂志

<p><b>OBJECTIVE</b>To establish a novel human monocytic leukemic cell line and characterize its biological features.</p><p><b>METHODS</b>Mononuclear cells isolated from the bone marrow of an acute monocytic leukemia (AML-M(5b)) patient at relapse were inoculated in a liquid culture system. And the biologic features of the established cell line SHI-1 were characterized by morphology, cytochemical staining, flow cytometry, karyotypic analysis, polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR), fluorescence in situ hybridization (FISH), tumorigenicity in nude mice, quantitative fluorescent polymerase chain reaction, broth medium culture, short tandem repeating sequences-PCR (STR-PCR), multiplex-FISH (M-FISH), and (3)H-thymidine incorporation assay.</p><p><b>RESULTS</b>A human acute monocytic leukemia cell line, SHI-1, was established and has proliferated continuously in vitro for over one year. The cell line presented typical morphology and immuno-profile of monocytic lineage with the original t(6;11)(q27;q23) and del(17)(p11) abnormalities. The MLL-AF6 fusion transcript was detected by RT-PCR. The rearrangement of MLL gene, deletion of p53 gene, and translocation between chromosomes 6 and 11 were revealed by FISH. A point mutation of ATC-->ACC at exon 6 of the p53 gene was found by sequencing of the PCR products. The clonality and the high tumorigenicity of the SHI-1 cell line were confirmed. Infections of EBV and mycoplasma were excluded. A derivative chromosome 7 resulting from a translocation between chromosomes 7 and 13, monosomy 18 and a minute derived from chromosome 8 in addition to t(6;11) and deletion(17)(p11) were detected by M-FISH in SHI-1 cells passaged to March 2003. Cell line authentication by STR-PCR confirmed the identity to the original leukemic cells of the patient. (3)H-thymidine incorporation assay showed that IL-4 and IL-15 had proliferative effects, while IFN-gamma, TNFalpha, IL-2, PDGF, and IL-7 had inhibitory effects on the cell line.</p><p><b>CONCLUSIONS</b>SHI-1 is a novel acute monocytic leukemia-derived cell line carrying t(6;11)(q27;q23) and p53 gene alteration and having high tumorigenicity in nude mice. It provides a new useful tool for leukemia research.</p>

Establishment of a transplantable human myeloid BALB/c nude mouse model / 中国实验血液学杂志

To establish a mouse model bearing transplantable human chronic myeloid leukemia for hematopoietic stem cell transplantation to treat leukemia, 4 - 5-week-old female BALB/c nude mice were given cyclophosphamide 2 mg/mouse at day -2, -1, and then the human chronic myeloid leukemia K562 cells were engrafted into the mice at day 0 by injection via tail vein or peritoneal cavity. PB and BM cells were collected, the CD45, CD13, and CD33 antigens were delected by using FCM, the bcr/abl fusion gene mRNA was examined by RT-PCR. The results showed that transplantable leukemic mice could be yielded from 4 - 5-week-old nude mice either by injection through tail vein or peritoneal cavity when the total number of inoculated tumor cells was more than 2 x 10(5) per mouse, whether being pretreated with 2 mg CTX/mouse or not. The transplanted mice could survive 30 - 60 day with leukemia. In conclusion, the mouse model bearing leukemia can be established by inoculation 2 x 10(5) K562 cells into immunodeficient BALB/c nude mice.

Establishment of a mouse model for detecting multi-drug resistant minimal residual leukemia cells expressing green fluorescent protein / 中国实验血液学杂志

This study aimed to investigate the pathophysiology and therapy of multi-drug resistant model of minimal residual leukemia in mice. The multi-drug resistant model of minimal residual leukemia was established by using P388/VCR-G cell line expressing enhanced green fluorescent protein (EGFP) and DBA mice. The results showed that P388/VCR-G were inoculated in the abdominal cavities of DBA mice, the incidence of leukemia was 100%. Any of these mice with leukemia could not obtain remission spontaneously. The model of leukemia was sensitive to cyclophosphamide (Cy) and the time of survival was related to the dose of Cy received. The logarithm of cells inoculated in mice correlated regressionally with the dose of Cy. So this model was ideal for research on minimal residual leukemia. The distribution of residual leukemia cells in complete remission was not uniform in different organs including liver, spleen, thymus and bone marrow. Minimal residual leukemia cells could be found by fluorescent microscopy in freezing tissue slice. It is concluded that the multi-drug resistant model of minimal residual leukemia expressing EGFP can be established by using P388/VCR-G cell line and DBA mice. The minimal residual leukemia cells can be observed by fluorescence microscopy in complete remission stage.

Poorly-immunogenic tumor is capable of inducing proliferation of CD4 (+) CD25 (+) regulatory T-lymphocytes in vitro / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the distribution of regulatory T-lymphocytes in the splenocytes cocultured with syngeneic low-immunogenic tumor cells, as compared with that of highly-immunogenic tumor cells, to investigate the mechanism underlining tumor evasion.</p><p><b>METHODS</b>Three different immunogenic tumor cells were cocultured with syngeneic splenocytes individually to mimic cancer immunity in vitro. The proliferation response of splenocytes was measured by thymidine incorporation. The distribution of TR cells, CD4(+) IFN-gamma (+) T cells and CD4(+) IL-10(+) T cells were analyzed by flow cytometry. The secretion of IFN-gamma and IL-10 in supernatants was measured by ELISA assay.</p><p><b>RESULTS</b>The stimulation Index of splenocytes cocultured with syngeneic highly-immunogenic H22 or FBL3 was much higher than that of poorly immunogenic melanoma D5. In each group, stimulation Index of splenocytes cocultured with allogeneic tumor cells was higher than that of the corresponding tumor immunity model. In addition, compared with those of highly-immunogenic tumors, there were more TR, CD4(+)IL-10(+) and less CD4 (+)IFN-gamma(+) T cells in the splenocytes, and higher IL-10 and lower IFN-gamma levels in the supernatant of the splenocytes stimulated with low-immunogenic D5 cells.</p><p><b>CONCLUSION</b>Poorly-immunogenic tumor cells can induce the proliferation of TR cells, which may play an important role in tumor evasion.</p>

Etude de l'activite cytotoxique in vitro des derives du cyclopentanone

The cytotoxicity of 30 cyclopentanone derivatives was studied in vitro, in a clonogenic assay using murine leukemia LI 210. Results are compared to those obtained with reference medicaments. 17 derivatives exhibit activities against L1 210 cells.

Study on blocking the leukemia immune escape after BMT by Fas-Fas ligand pathway / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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. The mice models of leukemia/lymphoma were constructed by inoculating female C57BL/6 mice (H-2b) with 10(5) EL4 cells/mouse through caudal vein. Donors of bone marrow grafts were syngeneic male mice. BMMCs were infected with AdsFas or AdEGFP 24 hours before (Group D or E). The following three groups were simultaneously used: Group A, no BMMCs transplanted; Group B, transplanted with BMMCs not infected with adenoviruses; Group C, only transfusing EL4 cells, neither irradiation nor BMT. The hematopoietic reconstitution, generation of leukemia/lymphoma and the survival rate were observed in all groups after BMT.</p><p><b>RESULTS</b>The adenovirus vectors were successfully constructed. The titre of virus after purification was up to 2.5 x 10(11) pfu/ml. Spleen indices examined 11 days after BMT were not obviously different among Group B, D and E (P > 0.05), but indices in Group A were significantly lower than those in the latter three groups (P < 0.01). Counts of leukocytes and platelets on +30 day showed mice were reconstituted satisfactorily in Group B and D, but very low in Group C and E. The Y-chromosomes existed 2 months after BMT and examination of bone marrow cytology showed that Group B and D were almost normal, but Group C and E had plenty of lymphoblast-like tumor cells. Tumors were obviously observed in the mice of Group C and E by histopathological examination, but the mice in Group B and D were normal. The survival rates were 0 (0/4) in Group A, 100% in Group B (6/6) and D (16/16), 12.5% (2/16) in Group C and 6.25% (1/16) in Group E respectively. It is demonstrated that, in contrast with the control (Group EGFP), survival rate was significantly increased in the sFas Group (P < 0.01).</p><p><b>CONCLUSIONS</b>The transfer of sFas gene by adenovirus changed the prognosis state of leukemia/lymphoma mice after auto-BMT. The transduction of sFas might block the effect of the immune escape of EL4 cells through FasL. These results could thus provide a new direction to find a way to treat the leukemia and its recurrence after BMT.</p>

Coculture of dendritic cell with cytokine-induced killer results in a significant increase in cytotoxic activity of CIK to tumor cells in vitro and in vivo / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore whether coculture of dendritic cells (DC) with cytokine-induced killer (CIK) lead to an increase of cytotoxicity against tumor cells in vitro and in vivo.</p><p><b>METHODS</b>DC and CIK were prepared from human peripheral blood mononuclear cells (PBMC) by conventional methods, the DC pulsed with or without NB4 leukemia cell lyses (LCL) was cocultured with the CIK (LCL-DC + CIK and DC + CIK), CIK was used as control. Cells phenotypes were analyzed by flow cytometry, secretion of IFN-gamma was determined by ELISPOT assay, and cytotoxicity was assayed in vitro with (51)Cr-release assay. A human leukemia cell NB4-bearing nude mice model was established to test in vivo antitumor efficacy and cell homing.</p><p><b>RESULTS</b>Compared with CIK, LCL-DC + CIK got a significant increasing of proliferation rate [(18.2 +/- 2.1) times vs (11.6 +/- 2.3) times, P < 0.05] and CD(3)(+)CD(56)(+) expression rate [(51.05 +/- 2.63)% vs (30.18 +/- 1.45)%, P < 0.05], and the number of IFN-gamma secreting cells was increased significantly [(13.86 +/- 3.28)/10(4) cells vs (8.74 +/- 2.53)/10(4) cells, n = 12, P < 0.05]. Meanwhile, LCL-DC + CIK led to an increase of cytotoxic activity to NB4, K562, and KG1a cells, and showed significant inhibition of the growth of transplanted tumor cells and increased tumor free survival rate of nude mice (100% vs 66.7%, P < 0.05), DiI labeled LCL-DC + CIK were detected in spleen, lymph node and tumor within a week after injection. There was no significant different in antitumor activity between LCL-DC + CIK cell and DC + CIK cell.</p><p><b>CONCLUSION</b>Coculture of CIK with DCs can promote the effect of CIK against tumor in vitro and in vivo. DC-CIK is promising as an immuno-therapeutic strategy for patients with leukemia.</p>

Induction of T-cell immunity against leukemia by dendritic cells pulsed with total RNA isolated from leukemia cells / 中华医学杂志(英文版)

<p><b>OBJECTIVES</b>To assess the feasibility and efficacy of eliciting leukemia-specific T-cell responses in syngeneic mice in vitro and in vivo using dendritic cells (DCs) pulsed with total RNA from leukemia cells.</p><p><b>METHODS</b>DCs generated from bone marrow culture in vitro in the presence of combined cytokines were pulsed with cellular total RNA isolated from cultured L615 cells by cationic lipid 1,2-dioleoyloxy-3-(trimethylammonium) propane (DOTAP). T-cell responses were evaluated by in vitro proliferation, and cytotoxicity assay. And in vivo immune protection and prognosis of mice with leukemia were studied.</p><p><b>RESULTS</b>DCs pulsed with total RNA isolated from cultured L615 cells (DCs/RNA) were remarkably effective in stimulating L615-specific T-cell response in vitro, but did not cross-react with other leukemia cells from syngeneic mice. Vaccination of naive mice with viable DCs/RNA vaccine was able to partly protect from challenge with a lethal dose of live L615 cells, leading to low leukemia incidence and overall survival prolongation. Statistically significant survival was also observed in a low lethal dose of L615-bearing mice that received treatment using viable DCs/RNA vaccine alone, suggesting that systemic administration of IL-2 could enhance the anti-tumor efficacy of leukemia RNA/DCs vaccine.</p><p><b>CONCLUSIONS</b>These data support the use of DCs/RNA vaccine as a feasible and effective route to elicit leukemia immunity against unidentified leukemia-associated antigens for treatment of leukemia-bearing animals.</p>

Experimental study of optimized H-2 haploidentical hematopoietic engraftment for the treatment of murine acute leukemia model / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the critical dose of T lymphocyte for preserving graft versus leukemia (GVL) while preventing GVHD in murine acute leukemia model treated with H-2 haploidentical hematopoietic stem cell transplantation (HSCT).</p><p><b>METHODS</b>(C57BL/6 x 615) F1 (H-2bk) mice which was inoculated with L615 cells to develop leukemic murine model was the recipient. The healthy C57BL/6 (H-2b) mice was the donor. CD(34)(+) cells from bone marrow and CD(3)(+)cells from spleen of the donor were purified by miniMACS. The purity of CD(34)(+) cells and CD(3)(+) cells were (81.5 +/- 2.4)% and (95.4 +/- 2.9)% respectively. Sixty-nine recipient mice were divided into seven groups. Group A received no treatment, group B received TBI only, the rest groups were irradiated 9 Gy by (60)Co and transfused 10(5) CD(34)(+) cells or mixed with 10(7) (E), 10(8) (F), 1.5 x 10(8) (G) of CD(3)(+) cells respectively. The mice were raised for 60 days, The cause of death was identified by pathology.</p><p><b>RESULTS</b>All mice in group E survived more than 60 days being significantly longer than that in the rest groups (p < 0.0001). The chimerisms from donor were 100% in the mice survived > 60 days. Mice died of leukemia relapse in group D and group E were significantly less than those in group C (p < 0.001). Mice died from GVHD in group G were significantly more than those in group E and group F (p < 0.001).</p><p><b>CONCLUSIONS</b>The leukemia relapse rate was highest in mice that were transplanted with CD(34)(+) cells alone. Those mice transfused with CD(3)(+) T lymphocyte in the graft higher than 10(8) cells died from the GVHD was significantly higher. The inclusive dosage of 5 x 10(7) CD(3)(+) T lymphocyte was enough to separate the GVHD from GVL.</p>

Study on nonmyeloablative allogeneic bone marrow transplantation in the treatment of L615 leukemia mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To establish strategies for preventing graft versus host disease (GVHD) and reducing treatment associated morbidity while preserving graft versus leukemia (GVL) effect in nonmyeloablative allogeneic bone marrow transplantation (allo-BMT), with or without donor lymphocyte infusion (DLI) after BMT.</p><p><b>METHODS</b>3 x 10(7) bone marrow cells mixed with 1 x 10(7) spleen cells from the same BALB/c mouse were transplanted into the nonablative irradiated inbred 615 mouse which received a single subcutaneous injection of 1 x 10(6) L615 leukemia cells three days before. The experiments were designed as follows (ten mice in each group): myeloablative BMT control group (group A), nonmyeloablative conditioning without BMT group (group B), nonmyeloablative BMT group (group C), and nonmyeloablative BMT + DLI group (group D). GVL effects were assessed by survival time, white blood cell count and L615 cells in peripheral blood and histologic changes. GVHD was assessed by signs of weight loss, ruffled fur, diarrhea and histologic changes of skin, liver and small intestines. Chimerism was detected by cytogenetic analysis and PCR technique.</p><p><b>RESULTS</b>The survival time of group A, B, C and D was (20.3 +/- 13.4), (15.9 +/- 1.1), (21.6 +/- 1.7) and (37.8 +/- 2.0) days, respectively, being no significant difference between group A and group C (P > 0.05). The survival time of group C was longer than that of group B (P < 0.01). And among group B, C and D, group D had the longest survival time (P < 0.01). GVHD signs and histologic changes were observed in 60% of control group mice at + 14 day, but none of group C and group D. 40% of mice in group A died of treatment associated morbidity within two weeks, but none in group C and group D. Allogeneic chimerism was kept in group A, but excluded gradually in group C.</p><p><b>CONCLUSION</b>GVL effect seems preserved in nonmyeloablative BMT mice, but weaker than that in myeloablative BMT mice. GVL effect seems to be enhanced by DLI after nonmyeloablative BMT. GVHD and transplantation associated morbidity seems to be reduced in nonmyeloablative BMT.</p>

Experimental study on blocking immune escape of leukemia cells in the recipient after bone marrow transplantation / 中华血液学杂志

<p><b>OBJECTIVE</b>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).</p><p><b>METHODS</b>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. Bone marrow mononuclear cells (BMMCs) were transfected with sFas or EGFP by adenovirus (adsFas or adEGFP) 24 hours before BMT (group D or E). The following three groups were set simultaneously: group A, no BMMCs transplanted; group B, BMMCs transplanted with no adenoviruses transfection; group C, EL4 cells transfusion only. Hematopoietic reconstitution, generation of leukemia/lymphoma and the survival rate were observed in all the groups after BMT.</p><p><b>RESULTS</b>The spleen indices examined 11 days after BMT were not obviously different among group B, D and E (P > 0.05), but in group A were significantly lower than those in the groups B, D, E (P < 0.01). The leukocyte and platelet counts on day 30 after BMT were recovered in group B and D, but were very low in group C and E. The Y-chromosomes appeared 2 months after BMT. Bone marrow pictures in group B and D were almost normal, but in group C and E had plenty of lymphoblast-like tumor cells. Tumors were obviously revealed in the mice of group C and E by histopathology examination, but did not in group B and D. The survival rate was 0 in group A, 100% in group B and D, 12.5% in group C and 6.25% in group E. Compared with that in group E, the survival was significantly increased in the sFas group (P < 0.01).</p><p><b>CONCLUSIONS</b>Graft transfected with sFas gene prolonged the post-BMT survival of leukemia/lymphoma mice. The transfection of sFas might block the effect of the immune escape of EL4 cells through FasL.</p>