Impact of posttransplant cyclophosphamide on the outcome of patients undergoing unrelated single-unit umbilical cord blood transplantation for pediatric acute leukemia.

BACKGROUND: Umbilical cord blood transplantation (UCBT) from unrelated donors is one of the successful treatments for acute leukemia in childhood. The most frequent side effect of UCBT is peri-engraftment syndrome (PES), which is directly associated with the greater prevalence of acute and chronic graft-versus-host-disease (aGvHD and cGvHD). In haploidentical stem cell transplantation, posttransplant cyclophosphamide (PTCY) has been demonstrated to be an effective method against GvHD. However, the effects of PTCY as a GvHD prophylactic in UCBT had not been investigated. This study aimed to evaluate the effects of PTCY on the outcomes of UCBT for pediatric acute leukemia. METHODS: This retrospective study included 52 children with acute leukemia who underwent unrelated single-unit UCBT after myeloablative conditioning regimens. The results from the PTCY and non-PTCY groups were compared. RESULTS: The incidence of transplantation-related mortality in non-PTCY and PTCY were 5% and 10% (p = 0.525), respectively. The incidence of relapse in non-PTCY and PTCY were 5% and 23% (p = 0.095), respectively. Second complete remission status (CR2) was an independent risk factor for relapse-free survival (hazard ratio = 9.782, p = 0.001). The odds ratio for sepsis or bacteremia incidence was significantly greater in the PTCY group (9.524, p = 0.017). PTCY group had increased rates of cytomegalovirus activity and fungal infection. The incidence of PES, aGvHD, cGvHD, and hemorrhagic cystitis in the PTCY group was lower than that in the non-PTCY group, although it was not significantly different. Additionally, higher doses of PTCY (29 mg/kg and 40 mg/kg) were associated with lower incidences of aGvHD and severe GvHD (65% and 29%, respectively) than lower doses (93% and 57%, respectively). Engraftment time and graft failure incidence were similar across groups. CONCLUSION: The results support the safety and efficiency of PTCY as part of PES controlling and GvHD prophylaxis in single-unit UCBT for children with acute leukemia. A PTCY dosage of 29 mg/kg to 40 mg/kg appears to be more effective in GvHD prophylaxis for UCBT patients.

Oroxylin A increases the sensitivity of temozolomide on glioma cells by hypoxia-inducible factor 1α/hedgehog pathway under hypoxia.

Microenvironmental hypoxia-mediated drug resistance is responsible for the failure of cancer therapy. To date, the role of the hedgehog pathway in resistance to temozolomide (TMZ) under hypoxia has not been investigated. In this study, we discovered that the increasing hypoxia-inducible factor 1α (HIF-1α) activated the hedgehog pathway in hypoxic microenvironment by promoting autocrine secretion of sonic hedgehog protein (Shh), and then upregulating transfer of Gli1 to the nucleus, finally contributed to TMZ resistance in glioma cells. Oroxylin A (C16H12O5), a bioactive flavonoid, could induce HIF-1α degradation via prolyl-hydroxylases-VHL signaling pathway, resulting in the inactivation of the hedgehog. Besides, oroxylin A increased the expression of Sufu, which is a negative regulator of Gli1. By this mechanism, oroxylin A sensitized TMZ on glioma cells. U251 intracranial transplantation model and GL261 xenograft model were used to confirm the reversal effects of oroxylin A in vivo. In conclusion, our results demonstrated that HIF-1α/hedgehog pathway conferred TMZ resistance under hypoxia, and oroxylin A was capable of increasing the sensitivity of TMZ on glioma cells in vitro and in vivo by inhibiting HIF-1α/hedgehog pathway and depressing the activation of Gli1 directly.

Modified conditioning regimen improves outcomes of unrelated donor peripheral blood stem cell transplantation for ß-thalassaemia major patients.

BACKGROUND: The objective of this study was to evaluate the feasibility of a modified conditioning regimen for the treatment of patients with ß-thalassaemia major (TM), using unrelated donor peripheral blood stem cell transplantation (UD-PBSCT). METHODS: A modified conditioning regimen based on intravenous busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin was performed in 50 consecutive childhood patients with ß-TM and a median age of 4.6 years (range, 2-12 years). According to Pesaro's classification, three classes of risk are identified using the criteria of degree of hepatomegaly, portal fibrosis, and quality of the chelation treatment. Patients with three adverse criteria constituted class III, none of the adverse criteria constituted class I, and one or two of the adverse criteria formed class II. Ten patients were class I, 36 class II, and four class III. All patients were transplanted with UDs containing 37 of 10/10 human leukocyte antigen (HLA)-matched pairs, 11 of 9/10 matched pairs, and two of 8/10 matched pairs. The median follow-up was 36 months (range, 9-96 months). RESULTS: All patients successfully achieved engraftment, two of whom developed persistent thrombocytopaenia. The incidence of acute graft-versus-host disease (aGVHD) grade III-IV and chronic graft-versus-host disease (cGVHD) were 12% and 8%, respectively. However, 8.3% of HLA-matched and 15.4% of HLA-mismatched patients developed aGVHD. The incidence of severe bacterial infections and fungal pneumonia was 12% and 20%, respectively. The 3-year overall survival, disease-free survival, graft rejection, and transplant-related mortality were 94%, 92%, 2%, and 6%, respectively. CONCLUSION: This modified conditioning protocol effectively improved outcomes of UD-PBSCT for patients with ß-TM.

Influence of c-Src on hypoxic resistance to paclitaxel in human ovarian cancer cells and reversal of FV-429.

SRC family kinase was documented to have vital roles in adjusting cancer cell malignant behaviors. To date, the role of c-Src, a member of SRC family kinase, in resistance to paclitaxel in human ovarian cancer cells under hypoxia has not been investigated. In the present study, we discovered that hypoxic environment suppressed paclitaxel-induced G2/M phase arrest and blockade of c-Src improved ovarian cancer cells' sensitivity to paclitaxel. FV-429, a derivative of natural flavonoid wogonin, could suppress gene expression and activation of c-Src, followed by deteriorated Stat3 nuclear translocation and its binding to HIF-1α, resulting in paclitaxel resistance reversal through G2/M arrest potentiation. Our study demonstrated that c-Src contributed to hypoxic microenvironment-rendered paclitaxel resistance in human epithelial ovarian cancer cells by G2/M phase arrest deterioration, and through c-Src suppression, FV-429 was capable of reversing the resistance by blocking c-Src/Stat3/HIF-1α pathway.

Oroxyloside A Overcomes Bone Marrow Microenvironment-Mediated Chronic Myelogenous Leukemia Resistance to Imatinib via Suppressing Hedgehog Pathway.

Imatinib (IM), as first inhibitor of the oncogenic tyrosine kinase BCR-ABL, has been widely used to treat chronic myeloid leukemia (CML) for decades in clinic. However, resistance to IM usually occurs in CML patients. The bone marrow (BM), as the predominant microenvironment of CML, secretes an abundant amount of cytokines, which may contribute to drug resistance. In current study, we utilized in vitro K562 co-culture model with BM stroma to investigate IM resistance. As a result, co-culturing of K562 with BM stroma was sufficient to cause resistance to IM, which was accompanied with the activation of hedgehog (Hh) signaling pathway and upregulation of BCR-ABL as well as its downstream proteins like phosphorylated Akt, Bcl-xL and survivin, etc. On the other hand, oroxyloside A (OAG), a metabolite of oroxylin A from the root of Scutellaria baicalensis Georgi, which had low toxic effect on K562 cells, was able to sensitize K562 cells co-cultured with BM stroma to IM treatment in vitro and in vivo. We observed that OAG suppressed Hh pathway and subsequently nuclear translocation of GLI1, followed by downregulation of BCR-ABL and its downstream effectors, thus facilitating IM to induce apoptosis of K562 cells. Together, BM microenvironment rendered K562 cells drug resistance through activating Hh signaling, however, OAG could overcome IM resistance of CML cells through inhibiting Hh-BCR-ABL axis in vitro and in vivo.

Wogonin reversed resistant human myelogenous leukemia cells via inhibiting Nrf2 signaling by Stat3/NF-κB inactivation.

Constitutive NF-E2-related factor 2 (Nrf2, NFE2L2) activation has been recently reported to play a pivotal role in enhancing cell survival and resistance to anticancer drugs in many tumors. Wogonin had strong reversal potency via reduction of Nrf2 mRNA in Adriamycin (ADR)-induced resistant human chronic myelogenous leukemia (CML) K562/A02, but the mechanism of reduction of Nrf2 mRNA was still unclear. In this study, we aimed to delineate the mechanism by which Wogonin suppressed transcription of Nrf2 in resistant CML cells and further evaluate the reversal effects of Wogonin on the established animal models. Data indicated that Wogonin suppressed transcription of Nrf2 by NF-κB inactivation. Wogonin inhibited the binding of p65 to Nrf2 by suppression of the κB-binding activity. Further research revealed the κB2 site was responsible for the decreased Nrf2 by Wogonin in resistant K562 cells. Furthermore, reduction of pY705-Stat3 was involved in inhibition of the binding of p65 to Nrf2 by Wogonin. In vivo, Wogonin potentiated the inhibitory effect of ADR on leukemia development by suppressing pY705-Stat3 and Nrf2 signaling. In summary, these results demonstrated Wogonin could combat chemoresistance effectively through inhibiting Nrf2 via Stat3/NF-κB signaling, and supported that Wogonin can be developed into an efficient natural sensitizer for resistant human myelogenous leukemia.

Activation of endoplasmic reticulum stress and the extrinsic apoptotic pathway in human lung cancer cells by the new synthetic flavonoid, LZ-205.

It has been shown that flavonoids have anti-tumor activity. In this study, LZ-205, a newly synthesized flavonoid, was found to be effective in inducing apoptosis in human lung cancer cells in vivo and in vitro. Mechanistically, LZ-205 triggers reactive oxygen species (ROS)-induced endoplasmic reticulum (ER) stress and unfolded protein response, which could be reversed by silencing CHOP, a mediator of the ER stress-associated apoptosis. In addition, LZ-205-induced apoptosis is accompanied by the activation of both the mitochondrial apoptotic and extrinsic pathways, followed by decreased mitochondrial membrane potential (ΔΨm) and the alteration of the expression of mitochondria-related pro- and anti-apoptotic proteins. LZ-205 exhibits a potential antitumor effect in BALB/c nude mice bearing H460 tumor with low systemic toxicity. In summary, both the ROS-mediated ER stress pathway and the exogenous apoptotic pathway are involved in LZ-205-induced apoptosis in vitro and in vivo. Our data show a therapeutic potential of LZ-205 for the treatment of lung cancer.

BM microenvironmental protection of CML cells from imatinib through Stat5/NF-κB signaling and reversal by Wogonin.

Constitutive Stat5 activation enhanced cell survival and resistance to imatinib (IM) in chronic myelogenous leukemia (CML) cells. However, the mechanism of Stat5 activation in mediating resistance to IM in bone marrow (BM) microenvironment has not been evaluated precisely. In this study, we reported HS-5-derived conditioned medium (CM) significantly enhanced IM resistance in K562 and KU812. Interestingly, upregulation of the proportion of CD34+ subpopulation was found in CML cells. Subsequently, the BCR/ABL-independent activation of Stat5 increased P-glycoprotein (P-gp) activity in CM-mediated protection of CML stem cells (LSCs) from IM. Further research revealed Stat5 activation increased the DNA binding activity of NF-κB though binding of p-Stat5 and p-RelA in nucleus. Moreover, highly acetylated RelA was required for Stat5-mediated RelA nuclear binding. The study further confirmed that Wogonin potentiated the inhibitory effects of IM on leukemia development by suppressing Stat5 pathway both in CM model and the K562 xenograft model. In summary, results clearly demonstrated BCR/ABL-independent Stat5 survival pathway could contribute to resistance of CML LSCs to IM in BM microenvironment and suggested that natural durgs effectively inhibiting Stat5 may be an attractive approach to overcome resistance to BCR/ABL kinase inhibitors.

LW-213 induces G2/M cell cycle arrest through AKT/GSK3ß/ß-catenin signaling pathway in human breast cancer cells.

LW-213 is a derivative of Wogonin and the anticancer activities of Wogonin have been reported. To study whether LW-213 inhibits cancer cells and explore a possible mechanism, we investigate the compound in several cancer cell lines. We found LW-213 arrests G2/M cycle in breast cancer cells by suppression of Akt/Gsk3ß/ß-catenin signaling pathway. In compound treated cells, cell cycle-related proteins cyclin A, cyclin B1, p-CDK1, p-Cdc25C, and p-Chk2 (Thr68) were upregulated, and ß-catenin nuclear translocation was inhibited. Electrophoretic mobility shift assay revealed LW-213 inhibits binding of ß-catenin/LEF complex to DNA. GSK3ß inhibitor LiCl and siRNA against GSK3ß partially reversed G2/M arrest in breast cancer MCF-7 cells. These results suggest LW-213 triggered G2/M cell cycle arrest through suppression of ß-catenin signaling. In BALB/c mice, growth of xenotransplanted MCF-7 tumor was also inhibited after treatment of LW-213. Regulation of cyclin A, cyclin B1, and ß-catenin by LW-213 in vivo was the same as in vitro study. In conclusion, we found LW-213 exerts its anticancer effect on cell proliferation and cell cycle through repression of Akt/Gsk3ß/ß-catenin signaling pathway. LW-213 could be a potential candidate for anticancer drug development.

GL-V9, a new synthetic flavonoid derivative, ameliorates DSS-induced colitis against oxidative stress by up-regulating Trx-1 expression via activation of AMPK/FOXO3a pathway.

GL-V9, a new synthesized flavonoid derivative, has been reported to possess anti-cancer properties in our previous studies. Uncontrolled overproduction of reactive oxygen species (ROS) has been implicated in oxidative damage of inflammatory bowel disease (IBD). In this study, we aimed to investigate the protective effect of GL-V9 against dextran sulfate sodium (DSS)-induced colitis. GL-V9 attenuated DSS-induced body weight loss, colon length shortening and colonic pathological damage. GL-V9 also inhibited inflammatory cells infiltration and decreased myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activities. Moreover, GL-V9 inhibited ROS and malondialdehyde (MDA) generation, but enhanced superoxide dismutase (SOD), glutathione (GSH) and total antioxidant capacity. GL-V9 reduced pro-inflammatory cytokines production in serum and colon as well. Mechanically, GL-V9 could increase Trx-1 via activation of AMPK/FOXO3a to suppress DSS-induced colonic oxidative stress. Furthermore, GL-V9 decreased pro-inflammatory cytokines and ROS production and increased the antioxidant defenses in the mouse macrophage cells RAW264.7 by promoting Trx-1 expression. In conclusion, our study demonstrated that GL-V9 attenuated DSS-induced colitis against oxidative stress by up-regulating Trx-1 via activation of AMPK/FOXO3a pathway, suggesting that GL-V9 might be a potential effective drug for colitis.

The overexpression and nuclear translocation of Trx-1 during hypoxia confers on HepG2 cells resistance to DDP, and GL-V9 reverses the resistance by suppressing the Trx-1/Ref-1 axis.

Microenvironmental hypoxia gives many tumor cells the capacity for drug resistance. Thioredoxin family members play critical roles in the regulation of cellular redox homeostasis in a stressed environment. In this study, we established a hypoxia-drug resistance (hypoxia-DR) model using HepG2 cells and discovered that the overexpression and nuclear translocation of thioredoxin-1 (Trx-1) are closely associated with this resistance through the regulation of the metabolism by the oxidative stress response to glycolysis. Intranuclear Trx-1 enhances the DNA-binding activity of HIF-1α via its interaction with and reducing action on Ref-1, resulting in increased expression of glycolysis-related proteins (PDHK1, HKII, and LDHA), glucose uptake, and lactate generation under hypoxia. Meanwhile, we found that GL-V9, a newly synthesized flavonoid derivative, shows an ability to reverse the hypoxia-DR and has low toxicity both in vivo and in vitro. GL-V9 could inhibit the expression and nuclear translocation of Trx-1 and then suppress HIF-1α DNA-binding activity by inhibiting the Trx-1/Ref-1 axis. As a result, glycolysis is weakened and oxidative phosphorylation is enhanced. Thus, GL-V9 leads to an increment in intracellular ROS generation and consequently intensified apoptosis induced by DDP.

[Therapeutic efficacy evaluation of rabbit anti-thymocyte globulin combined with cyclosporine A in children with aplastic anemia].

This study was aimed to investigate the therapeutic efficacy of rabbit anti-thymocyte globulin (r-ATG) combined with cyclosporine A (CsA) and to analyse the efficacy-related factors in children with aplastic anemia (AA). Twenty five AA children treated with r-ATG [3.5 mg/(kg·d)×5 days] combined with CsA were analyzed retrospectively. The lymphocyte subgroups, CD4(+)/CD8 ratio and expression of CD55, CD59 on surface of neutrophils and erythrocytes in peripheral blood were detected by direct immunofluorescence method and flow cytometry; the responsive time, effective rate, adverse effects and infections after immunosuppressive therapy (IST) were analyzed; the distribution of T-lymphocyte subgroups in IST-effective and IST-uneffective groups was compared, and therapeutic efficacy-related factors were evaluated. The results showed that the response to treatments was found in 21 out of 25 cases, the total responsive rate was 84.0%; the response time was 3 - 6 months, average of 4 months; the effective rates in month 3, 6, 9, 12 after treatment were 56.0%, 72.0%, 80.0% and 84.0% respectively. The AA children with age ≥ 5 years old, course of disease < 6 months and absolute neutrophil value ≥ 1.5 ×10(9)/L on 30 days after IST had good curative effect; the effective rate in AA children with age ≥ 5 years old, course of disease < 6 months, high or reverse ratio of CD4(+)/CD8(+) and absolute neutrophil value ≥ 1.5×10(9)/L after IST was higher than that in AA children with age < 5 years old, course of disease ≥ 6 months, normal ratio of CD4(+)/CD8(+) and absolute neutrophil value after IST < 1.5×10(9)/L (94.4% vs 57.1%, 90.4% vs 50.0%, 94.1% vs 62.5%, 94.1% vs 62.5%) (P < 0.05). The high effective rate was observed in AA children with decrease of CD55 and CD59 expression, but there was no significant difference (P > 0.05) as compared with normal expression of CD55, CD59. It is concluded that the treatment using r-ATG (3.5 mg/kg·d × 5 d) combined with CsA is a safe and effective for children with AA. Age, course of disease and absolute neutrophil value on 30 days after IST are the main factors affecting curative affect.

[Analysis of one case of adolescent blastic plasmacytoid dendritic cell neoplasm].

This study was purposed to summarize the clinical characteristics and laboratorial data of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in pediatric patients in order to enhance understanding this disease in diagnosis and therapy. A rare case of BPDCN in children was enrolled in this study. The blood routine test, examination of bone marrow cell morphology, histopathology and immunophenotype of the skin lesions were performed and analysed, the single cell suspensions of the biopsied skin mass were detected by flow cytometry. The results showed that tumor cells expressed CD4, CD56, CD43 and CD123, while not expressed CD19, CD20, CD3, CD8, CD13, CD11b and myeloperoxidase (MPO). According to the clinical and laboratorial features and the results from histopathological and immunophenotype examinations, BPDCN was confirmed. It is concluded that BPDCN in children is an extremely rare hematopoietic malignancy with presenting a rapidly and fatally aggressive clinical course. The diagnosis of this disease is mainly based on the clinical presentations, pathologic and immunohistochemical features. BPDCN is a highly aggressive disease, its prognosis is very poor, its pathogenesis remans still unclear. A standard treatment protocol for BPDCN has not yet been established.

Rabbit-antithymocyte globulin combined with cyclosporin A as a first-line therapy: improved, effective, and safe for children with acquired severe aplastic anemia.

PURPOSE: Acquired aplastic anemia is an organ-specific auto-immune disease characterized by pancytopenia and hypoplastic bone marrow. Immunosuppression with anti-thymocyte globulin (ATG) and cyclosporine A (CsA) is an effective and safe therapy for patients without undergoing hematopoietic stem cell transplantation. The aim of the current study was to investigate the effect of rabbit-ATG (r-ATG) combined with CsA as an intensive immunosuppressive therapy (IST) for acquired severe aplastic anemia (SAA) in children. METHODS: From January 2003 to November 2008, 46 children (30 boys and 16 girls), with a median age of 7 years (between 2 and 15 years) were diagnosed with acquired SAA. They received an IST of r-ATG combined with CsA. The average time was 3.4 months (ranging from 1 to 13 months). The effective rates 3, 6, 9, and 12 months after treatment were 30.4, 65.2, 78.8, and 84.8%, respectively. After 2 years of follow-up, the response rate was 84.8% (39/46). No response was found in five cases and relapse was found in two. RESULTS: Among the five cases without response, two received unrelated hematopoietic stem cell transplantation and are already disease-free and two died from infection caused by long-term dependence on infusion. No myelodysplastic syndrome or acute myeloid leukemia was found among the patients. CONCLUSIONS: We propose that r-ATG combined with CsA as an intensive IST is effective and safe in treating acquired SAA in children.

[Sequentially inducting murine embryonic stem cells into hematopoietic stem cells in vitro by hematopoietic development procedure for reconstitution of hematopoiesis in vivo].

This study was purposed to directly induce murine embryonic stem cells (ESC) into hematopoietic stem cells (HSC) by simulating the spatial and temporal hematopoietic microenvironment changes in embryonic development, and to investigate the function of in vivo hematopoietic reconstitution of these HSC. E14 ESC were induced into embryoid body (EB) firstly. Then the cells from EB were further co-cultured with human aorta-gonad-mesonephros (AGM) region, fetal liver (FL) and bone marrow (BM) stromal cells in Transwell non-contact system in sequential orders. After 6 days of each co-cultured stage, the induced cells derived from EB were collected to analyze the Sca-1(+)c-Kit(+) cells by flow cytometry, check teratoma formation and transplant to BALB/C female mice exposed to lethal dose (60)Co γ-ray. The recipient mice were divided randomly into 5 groups: AGM, AGM + FL, AGM + FL + BM, irradiation control and normal control groups. The survival rates, hematopoietic reconstitution and engraftment of donor cells in the different groups were monitored. The results showed that Sca-1(+)c-Kit(+) cell level in EB cells co-cultured with human AGM region and FL stromal cells reached to peak value (21.96 ± 2.54)%. Teratomas could be found in NOD-SCID mice after subcutaneous injection of EB cells co-cultured with human AGM region stromal cells, while there was no teratoma in the mice after subcutaneous injection of EB cells induced by human AGM region and FL stromal cells. The recipients in AGM group and irradiation control group all died. The survival rate was 77.8% in AGM+FL group, and 66.7% in AGM+FL+BM group. The peripheral blood cell count was near normal at day 21 after transplantation, and Sry gene copies from donor could be detected in recipient mice of these two groups. It is concluded that sequentially inductive system with feeder cells from human AGM region, fetal liver and bone marrow simulating embryonic defined hematopoiesis procedures can enhance the directed differentiation of ESC into HSC which can safely reconstitute hematopoiesis in vivo.

[Effects of human aorta-gonad-mesonephros region stromal cells on inducing differentiation of murine embryonic stem cells into hematopoietic stem/progenitor cells in vitro].

This study was aimed to investigate the effect of human aorta-gonad-mesonephros (AGM) region stromal cells on differentiation of murine embryonic stem cells (ESC) into hematopoietic stem cells (HSC) in vitro and to clarify their effect mechanism. E14 murine ESC were induced into embryo body (EB) firstly. Then the EB cells were further co-cultured with the stromal cells from human AGM region, fetal liver (FL) or bone marrow (BM) in Transwell non-contact system. According to the different culture methods, the EB cells were divided into 6 groups including EB control group, AGM group, FL group, BM group, AGM + FL group and AGM + BM group. The induced cells derived from EB were collected for Sca-1(+)/c-Kit(+) cells analysis by flow cytometry and colony forming unit (CFU) assay. The results showed that Sca-1(+)/c-Kit(+) cell proportion of EB cells significantly increased after being induced by different stromal cells (p < 0.01). The AGM + FL group had most Sca-1(+)/c-Kit(+) cells for the positive cell proportion reached (21.96 ± 2.54) % (p < 0.01). The Sca-1(+)/c-Kit(+) cell proportion of AGM + BM group was much high than that of BM group too (p < 0.01). The EB control group showed CFU amount less than any other groups, while the CFU amount of AGM + FL, AGM + BM groups were higher, especially in the AGM + FL group (p < 0.01). It is concluded that the human AGM region stromal cells may help to maintain certain number of primitive HSC with high proliferation potential. Human AGM region, FL or BM stromal cells, applied in sequential orders, can significantly expand in vitro the primitive hematopoietic stem/progenitor cells derived from ESC.

Allogeneic hematopoietic stem cell transplantation for childhood aplastic anemia: prospective trial in China.

We aim to investigate the efficacy and safety of the treatment with fully matched allogeneic hematopoietic stem cell transplants for children with severe aplastic anemia (SAA) in the first prospective trial in China. Six SAA children received allogeneic hematopoietic stem cell transplantation combined with chemotherapy. Five patients had successful engraftment while the sixth child regained normal peripheral blood counts consistent with spontaneous autologous hematopoiesis. Mean duration of follow-up was 2.75 years, and survival was 83%(5/6). The results indicated that allogeneic hematopoietic stem cell transplantation is a good option for the treatment of children with severe aplastic anemia.

Bone marrow mesenchymal stem cells reduce the antitumor activity of cytokine-induced killer/natural killer cells in K562 NOD/SCID mice.

Adoptive cellular immunotherapy is an important treatment to eliminate residual tumor cells after hematopoietic stem-cell transplantation. Bone marrow mesenchymal stem cells (MSC) have previously been shown to exert immunoregulation functions, including inhibition of proliferation and killing activities of T cells and natural killer (NK) cells in vitro and reduction of the graft-versus-host disease. MSC can survive in vivo for a long period of time, the influence of MSC on the antitumor activity of subsequently infused immune killer cells is not clear. The aim of this study was to investigate the influences of MSC infused via different paths and at different times on the antitumor activities of cytokine-induced killer (CIK)/NK cells derived from umbilical cord blood in K562 NOD/SCID mice. The potential interaction mechanisms of MSC and CIK/NK cells infused through different paths using different intervals in vivo were subsequently explored. The results show that the antitumor activities of CIK/NK cells was inhibited by MSC when injected via the same path (tail vein), and the suppressive effect of MSC on CIK/NK cells were less pronounced when they were injected separately through different paths. There were no effects of MSC on the antitumor activities of CIK/NK cells if the MSC and CIK/NK cells were injected with a 48-h interval. Moreover, the suppressive effect continuous, even if MSC were infused 48 h earlier than CIK/NK cells. It suggests that pre-injected MSC can reduce the antitumor activities of CIK/NK cells in vivo. The probable mechanisms are that MSC and CIK/NK cells might have a greater opportunity to meet and interact if they are injected simultaneously via the same path. The suppression of MSC on CIK/NK cells in vivo mainly takes place in the reticuloendothelial system, including the lung and the liver.