MicroRNA-3196 is inhibited by H2AX phosphorylation and attenuates lung cancer cell apoptosis by downregulating PUMA.

Histone H2AX is a tumor suppressor protein that plays an important role in apoptosis. However, the mechanism underlying the association of H2AX with apoptosis in cancer cells remains elusive. Here, we showed that H2AX knockdown in lung cancer A549 cells affected the expression of 16 microRNAs (miRNAs), resulting in the downregulation of 1 and the upregulation of 15 miRNAs. MicroRNA-3196 (miR-3196) was identified as a target of H2AX and shown to inhibit apoptosis in lung cancer cells by targeting p53 upregulated modulator of apoptosis (PUMA). Phosphorylated H2AX (γH2AX) was shown to bind to the promoter of miR-3196 and regulate its expression. In addition, H2AX phosphorylation increased H3K27 trimethylation in the promoter region of miR-3196 and inhibited the binding of RNA polymerase II to the promoter of miR-3196, leading to the inhibition of miR-3196 transcription. Taken together, these results indicated that H2AX phosphorylation regulates apoptosis in lung cancer cells via the miR-3196/PUMA pathway.

Identification of MicroRNAs Involved in Growth Arrest and Apoptosis in Hydrogen Peroxide-Treated Human Hepatocellular Carcinoma Cell Line HepG2.

Although both oxidative stress and microRNAs (miRNAs) play vital roles in physiological and pathological processes, little is known about the interactions between them. In this study, we first described the regulation of H2O2 in cell viability, proliferation, cycle, and apoptosis of human hepatocellular carcinoma cell line HepG2. Then, miRNAs expression was profiled after H2O2 treatment. The results showed that high concentration of H2O2 (600 µM) could decrease cell viability, inhibit cell proliferation, induce cell cycle arrest, and finally promote cell apoptosis. Conversely, no significant effects could be found under treatment with low concentration (30 µM). miRNAs array analysis identified 131 differentially expressed miRNAs (125 were upregulated and 6 were downregulated) and predicted 13504 putative target genes of the deregulated miRNAs. Gene ontology (GO) analysis revealed that the putative target genes were associated with H2O2-induced cell growth arrest and apoptosis. The subsequent bioinformatics analysis indicated that H2O2-response pathways, including MAPK signaling pathway, apoptosis, and pathways in cancer and cell cycle, were significantly affected. Overall, these results provided comprehensive information on the biological function of H2O2 treatment in HepG2 cells. The identification of miRNAs and their putative targets may offer new diagnostic and therapeutic strategies for liver cancer.

[Analysis of Risk Factors and Therapeutic Strategies for Relapse of Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation].

OBJECTIVE: To analyze the risk factors of patients with relapsed leukemia after allogeneic hematopoietic stem cell transplantation, and to explore the therapeutic strategies for recurrence. METHODS: The Cox proportional hazard regression model was used for univariate and multivariate analysis of transplantation-related index, a single center retrospective study of clinical data of 202 cases of leukemia received allo-HSCT from March 2004 to October 2014 had been conducted to screen the risk factors for recurrence after transplantation. RESULTS: In the leukemia patients received allo-HSCT, 68 cases relapsed. The relapse rate was 33.6%. The median time of relapse was 4(1.5-26 ) months. Univariate analysis indicated that there were 5 risk factors related with the disease relapse(P<0.05), including the type of disease, extramedullary disease prior to transplant, the course of induced remission, the status of disease at HSCT and chronic graft versus host disease(cGVHD). Multivariate analysis showed that extramedullary disease prior to transplant(RR=2.622, 95%CI 1.139-6.037), the course of induced remission(RR=1.156, 95%CI 0.682-1.957), cGVHD (RR=1.728,95%CI 0.999-2.991) were independent risk factors for relapse of the patients received transplantation. Treatment strategies for the relapsed patients included withdraw immunosuppressant, donor lymphocyte infusion, systemic chemotherapy and local radiotherapy, targeted therapy, and second transplantation. Individualized choice was needed according to the relapsed site. The relapse-related mortality was 25.2%. CONCLUSION: The relapsed patients with leukemia after allo-HSCT have poor prognosis, early interference has good effect. The evaluation and prevention of risk factors before transplantation is even more important.

MicroRNA­1915­3p prevents the apoptosis of lung cancer cells by downregulating DRG2 and PBX2.

Micro (mi)RNAs are short non­coding RNA molecules, which post­transcriptionally regulate gene expression and exert key roles in cell growth, differentiation and apoptosis. In the present study, the mechanism and the function of miR­1915­3p in the apoptotic regulation of lung cancer cell lines (NCI­H441 and NCI­H1650) were investigated. The expression analysis confirmed that the expression of miR­1915­3p was markedly decreased in the apoptotic cells. The overexpression of miR­1915­3p in the lung cancer cells prevented apoptosis induced by etoposide. Developmentally regulated GTP­binding protein 2 (DRG2) and pre­B cell leukemia homeobox 2 (PBX2) were identified as downstream targets of miR­1915­3p, which was shown to bind directly to the 3'­untranslated region of DRG2 and PBX2, subsequently lowering their mRNA and protein expression levels. Co­expression of miR­1915­3p and DRG2/PBX2 in the NCI­H441 and NCI­H1650 cells partly circumvented the effect of miR­1915­3p on apoptosis. The results in the present study revealed that miR­1915­3p functions as a silencer of apoptosis, which regulates lung cancer apoptosis via targeting DRG2/PBX2, and consequently this miRNA may be a putative therapeutic target in lung cancer.

[Unrelated Donor Peripheral Blood Stem Cell Transplantation Combined with Umbilical Cord Mesenchymal Stem Cells in Patients with Hematologic Malignancies].

OBJECTIVE: To explore the safety and efficiency of unrelated donor peripheral blood stem cells (URD-PBSC) transplantation combined with umbilical cord mesenchymal stem cells (UC-MSC). METHODS: The clinical data of 49 patients received unrelated donor peripheral blood stem cells transplantation (URD-PBSCT) for treating hematologic malignancies were retrospectively evaluated, including 12 ANLL, 17 ALL, 18 CML and 2 MDS. Out of them, 22 patients received the URD-PBSCT combined with UC-MSC and 27 patients received only URD-PBSCT. The average number of infusing UC-MSC was 1.0 × 106/kg in the UC-MSC+URD-PBSCT group. RESULTS: As compared with URD-PBSCT group, in UC-MSC+URD-PBSCT group the median recovery time of neutrophilc granulocytes was shorter (12 d vs 15 d) (P = 0.041), the incidence and severity of chronic graft versus host disease (cGVHD) were lower (20.0% vs 51.9%) (P = 0.026) (5.0% vs 33.3%) (P = 0.040), the incidence of CMV infection after transplantation was higher (81.8% vs 51.9%) (P = 0.028). In addition to these, the differences were not statistically significant in term of implantation level, PLT reconstitution, aGVHD, lung infection, hemorrhagic cystitis, 1-year relapse and survival between the 2 groups (P > 0.05). CONCLUSION: The transplantation of URD-PBSC combined with UC-MSC is effective and safe. The speed of neutrophils reconstitution is faster. The incidence and severity of cGVHD are lower, but the attention should be paid to prevent the CMV infection.

MiRNA-1469 promotes lung cancer cells apoptosis through targeting STAT5a.

MicroRNAs play key roles in cell growth, differentiation, and apoptosis. In this study, we described the regulation and function of miR-1469 in apoptosis of lung cancer cells (A549 and NCI-H1650). Expression analysis verified that miR-1469 expression significantly increased in apoptotic cells. Overexpression of miR-1469 in lung cancer cells increased cell apoptosis induced by etoposide. Additionally, we identified that Stat5a is a downstream target of miR-1469, which can bind directly to the 3'-untranslated region of the Stat5a, subsequently reducing both the mRNA and protein levels of Stat5a. Finally, co-expression of miR-1469 and Stat5a in A549 and NCI-H1650 cells partially abrogated the effect of miR-1469 on cell apoptosis. Our results show that miR-1469 functions as an apoptosis enhancer to regulate lung cancer apoptosis through targeting Stat5a and may become a critical therapeutic target in lung cancer.

Resveratrol induces apoptosis of human chronic myelogenous leukemia cells in vitro through p38 and JNK-regulated H2AX phosphorylation.

AIM: The phosphorylation of histone H2AX, a novel tumor suppressor protein, is involved in regulation of cancer cell apoptosis. The aim of this study was to examine whether H2AX phosphorylation was required for resveratrol-induced apoptosis of human chronic myelogenous leukemia (CML) cells in vitro. METHODS: K562 cells were tested. Cell apoptosis was analyzed using flow cytometry, and the phosphorylation of H2AX and other signaling proteins was examined with Western blotting. To analyze the signaling pathways, the cells were transfected with lentiviral vectors encoding H2AX-wt or specific siRNAs. RESULTS: Treatment of K562 cells with resveratrol (20-100 µmol/L) induced apoptosis and phosphorylation of H2AX at Ser139 in time- and dose-dependent manners, but reduced phosphorylation of histone H3 at Ser10. Resveratrol treatment activated two MAPK family members p38 and JNK, and blocked the activation of another MAPK family member ERK. Pretreatment with the p38 inhibitor SB202190 or the JNK inhibitor SP600125 dose-dependently reduced resveratrol-induced phosphorylation of H2AX, which were also observed when the cells were transfected with p38- or JNK-specific siRNAs. Overexpression of H2AX in K562 cells markedly increased resveratrol-induced apoptosis, whereas overexpression of H2AX-139m (Ser139 was mutated to block phosphorylation) inhibited resveratrol-induced apoptosis. K562 cells transfected with H2AX-specific siRNAs were resistant to resveratrol-induced apoptosis. CONCLUSION: H2AX phosphorylation at Ser139 in human CML cells, which is regulated by p38 and JNK, is essential for resveratrol-induced apoptosis.

[Influence of calcineurin on apoptosis of pre-B lymphocytes and the leukemia cells derived from pre-B lymphocytes].

This study was aimed to compare the differential expressions of calcineurin (PP2B, PP3) in the mouse Pre-B cell lines (S9) and the tumor cell lines (S4C2) derived from pre-B lymphocytes, and to clarify its possible mechanism involving in the leukemia cell apoptosis. The quantitative real-time PCR was used to detect the differential expressions of H2AX-associated phosphakinase ATM, ATR, DNA-PKs, JNK1, P38 and the γ-H2AX-related phosphatase PP1, PP2A, calcineurin, PP4, PP6, PP5 between S9 and S4C2 cell lines. CCK-8 assay and flow cytometry were used to detect the effect of imatinib (IM) and cyclosporine A (CsA) on cytotoxicity and apoptosis of 2 cell lines. The Western blot was used to detect the effects of 2 drugs on apoptosis of S9 and S4C2 cell lines. The results showed that the expression level of calcineurin gene in the leukemia cell S4C2 was about 3.5 times of that in S9 cells, while the expression of other genes in these 2 kinds of cells was not significantly different. The apoptosis and toxicity of IM and CsA on S4C2 cells was significantly stronger than that on S9 cells. The expression level of calcineurin in S4C2 cells was higher than that in S9 cells.When CsA inhibited the calcineurin activity, the expression of DNA damage marker γ-H2AX in S9 cells was significantly lower than that in S4C2 cells,while the expression level of γ-H2AX between the two cell lines was no significantly different after treatment with imatinib, the expression level of γ-H2AX in S9 cells was lower than that in S4C2 cells when the two drugs were combined. It is concluded that the calcineurin plays a role of anti-apoptosis in B leukemic cells, cyclosporine A can promote the leukemia cell apoptosis.

[Allogeneic hematopoietic stem cell transplantation for chronic myelomonocytic leukemia and juvenile myelomonocytic leukemia].

This study was purposed to explore the therapeutic efficacy and influencing factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with chronic myelomonocytic leukemia (CMML) and in patients with juvenile myelomonocytic leukemia (JMML). The clinical data of 3 cases of CMML and 2 cases of JMML underwent allo-HSCT were analysed in term of multiparameter. The results showed that the hematopoietic stem cells in 5 patients grafted successfully. One case of JMML died of pulmonary disease, other 4 cases survive without disease. The analysis found that the disease burden before transplant, chromosome karyotype, acute GVHD II-IV and poor risk cytogenetics all associated with the relapse rate and disease-free survival rate of CMML. The low intensity conditioning regimen was better than myeloablative conditioning regimen. Type of donor and source of stem cells did not statistically and significantly affect OS and RFS. The splenectomy before allo-HSCT as well as spleen size at time of the alloHSCT did not influence on posttransplantation outcome of JMML. However, cord blood HSCT for JMML patients delayed hematologic recovery as compared to that of bone marrow or peripheral blood HSCT. The age, GVHD, HbF level played an important role in leukemia replace. It is concluded that the allogeneic hematopoietic stem cell transplantation is a curative regimen for CMML and JMML, but there also is a serial problems to be resolved.

[Effect of BU and CY versus TBI and CY as conditioning regimens on the efficacy of haploidentical stem cell transplantation in patients with hematologic malignancy].

OBJECTIVE: To investigate the therapeutic effects of the conditioning regimen with busulfan plus cyclophosphamide (BU+CY) or total body irradiation plus cyclophosphamide (TBI+CY) on haploidentical stem cell transplantation (HSCT) in hematologic malignancy. METHODS: The clinical outcomes of 77 HSCT recipients with hematologic malignancy from January 2001 to December 2010, including 21 AML, 33 ALL, 19 CML and 4 MDS were retrospectively evaluated. Among them, 65 patients obtained complete remission (CR) and 12 non-remission (NR) before transplantation; 39 patients received conditioning regimen with BU+CY, and 38 with TBI+CY. RESULTS: There were no statistically significant differences in hematopoietic reconstitution, disease free survival (DFS), and transplant- related mortality (TRM) between two groups. The estimated 3- years overall survival (OS) was 56.4% for BU+CY and 31.6% for TBI + CY (P=0.0283). The overall relapse rate was similar between two groups (15.4% vs 34.2%; P=0.1538). However, the accumulative probability of relapse at 1-year was significantly lower in BU+CY than that in TBI+CY group (2.56% vs 26.67%; P=0.0116). The incidence of grade II-IV graft-versus-host disease (GVHD) was similar between two regimens (20.5% in BU+CY group and 18.4% in TBI+CY group; P=0.8168). The incidence of chronic GVHD (cGVHD) was higher in the TBI+CY group than that of BU+CY group (84.6% vs 41.1%; P=0.0007). The extensive GVHD obtained the similar outcome (30.8% vs 10.5%; P=0.0416). CONCLUSION: Patients using BU+CY as conditioning regimen before transplant could obtain a better 3 year OS and lower short-term relapse rate. The TBI+CY conditioning regimen could significantly increase the incidence of cGVHD without increasing the acute GVHD. BU+CY conditioning regimen could be used for HSCT, but the attention should be paid to prevent the related hemorrhagic cystitis.

H2AX phosphorylation regulated by p38 is involved in Bim expression and apoptosis in chronic myelogenous leukemia cells induced by imatinib.

Increasing evidence suggests that histone H2AX plays a critical role in regulation of tumor cell apoptosis and acts as a novel human tumor suppressor protein. However, the action of H2AX in chronic myelogenous leukemia (CML) cells is unknown. The detailed mechanism and epigenetic regulation by H2AX remain elusive in cancer cells. Here, we report that H2AX was involved in apoptosis of CML cells. Overexpression of H2AX increased apoptotic sensitivity of CML cells (K562) induced by imatinib. However, overexpression of Ser139-mutated H2AX (blocking phosphorylation) decreased sensitivity of K562 cells to apoptosis. Similarly, knockdown of H2AX made K562 cells resistant to apoptotic induction. These results revealed that the function of H2AX involved in apoptosis is strictly related to its phosphorylation (Ser139). Our data further indicated that imatinib may stimulate mitogen-activated protein kinase (MAPK) family member p38, and H2AX phosphorylation followed a similar time course, suggesting a parallel response. H2AX phosphorylation can be blocked by p38 siRNA or its inhibitor. These data demonstrated that H2AX phosphorylation was regulated by p38 MAPK pathway in K562 cells. However, the p38 MAPK downstream, mitogen- and stress-activated protein kinase-1 and -2, which phosphorylated histone H3, were not required for H2AX phosphorylation during apoptosis. Finally, we provided epigenetic evidence that H2AX phosphorylation regulated apoptosis-related gene Bim expression. Blocking of H2AX phosphorylation inhibited Bim gene expression. Taken together, these data demonstrated that H2AX phosphorylation regulated by p38 is involved in Bim expression and apoptosis in CML cells induced by imatinib.

[Treatment of leukemia with immunized donor cell infusion after nonmyeloablative haploidentical bone marrow transplantation].

This study was purposed to investigate the therapeutic effects of early transfusion of immunized donor lymphocytes after haploidentical transplantation by means of mouse model of nonmyeloablative haploidentical bone marrow transplantation. CB6F1 female mouse was served as recipient and C57BL/6 male mouse was served as donor. Each CB6F1 female mouse was subjected to intravenous transfusion with 1×10(6) erythroleukemia (EL9611) cells at day 4 before transplantation, followed with intraperitoneal injection of Ara-C (0.015 g) respectively at day 2 and day 1, then conditioned for BMT with TBI (450 cGy) at day 1 before transplantation. After conditioning (day 0), each of recipients was transplanted with 6×10(7) mixture of bone marrow and spleen cells from the C57BL/6 mice, and was infused with 6 × 10(7) immunized donor lymphocytes at day 15 after transplantation. All treated animals were evaluated for survival, development of leukemia and aGVHD. The donor CD3(+) cell chimerism and sex determining region Y gene (SRY)in recipients were monitored periodically after transplantation. The results showed tht all mice with only inoculation of 10(6) EL9611 cells survived for 15 ± 1 days (n = 4); all mice of other groups obtained the varying degrees of implantation. SRY could be detected at day 30 and 60 after transplantation. The chimerism of donor CD3(+) cells in mixed bone marrow transplantation (MT) group at day 14, 30 and 60 respectively reached 17.95% ± 12.03%, 37.34% ± 2.78% and 47.06% ± 6.1%. In donor lymphocyte infusion (DLI) group it reached 69.78% ± 12.62%, 75% ± 15.97%, 83.41% ± 16.07% at day 30, 45 and 60 after transplantation. The mice of MT and DLI group survived for 66.66 ± 1.47 days and 78.2 ± 7.82 days. It is concluded that the high tumor burden before transplantation can affect donor cell engraftment and prognosis.Early post-transplanted infusion of immunized lymphocytes from donor can help to improve the therapeutic efficacy and survival.

Genome-wide transcriptional analysis of apoptosis-related genes and pathways regulated by H2AX in lung cancer A549 cells.

Histone H2AX is a novel tumor suppressor protein and plays an important role in apoptosis of cancer cells. However, the role of H2AX in lung cancer cells is unclear. The detailed mechanism and epigenetic regulation by H2AX remain elusive in cancer cells. We showed that H2AX was involved in apoptosis of lung cancer A549 cells as in other tumor cells. Knockdown of H2AX strongly suppressed apoptosis of A549 cells. We clarified the molecular mechanisms of apoptosis regulated by H2AX based on genome-wide transcriptional analysis. Microarray data analysis demonstrated that H2AX knockdown in A549 cells affected expression of 3,461 genes, including upregulation of 1,435 and downregulation of 2,026. These differentially expressed genes were subjected to bioinformatic analysis for exploring biological processes regulated by H2AX in lung cancer cells. Gene ontology analysis showed that H2AX affected expression of many genes, through which, many important functions including response to stimuli, gene expression, and apoptosis were involved in apoptotic regulation of lung cancer cells. Pathway analysis identified the mitogen-activated protein kinase signaling pathway and apoptosis as the most important pathways targeted by H2AX. Signal transduction pathway networks analysis and chromatin immunoprecipitation assay showed that two core genes, NFKB1 and JUN, were involved in apoptosis regulated by H2AX in lung cancer cells. Taken together, these data provide compelling clues for further exploration of H2AX function in cancer cells.

[Detection of the expression of NK ligands in acute leukemia cell lines by real-time PCR].

OBJECTIVE: To detect the expression profile of NK ligands in acute leukemia cell lines and investigate the differential expression pattern between acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). METHODS: Using quantitative real-time PCR, 23 NK ligands (MICA, MICB, ULBP-1, ULBP-2, ULBP-3, ULBP-4, HLA-E, HLA-G, CD48, NBTA, HLA-F, LLT-1, PVR, Nectin2, CD72, CD80, ICAM-1, LFA-3, CRACC, Fas, DR4, DR5, TNFR1) were detected in 6 acute leukemia cell lines, including 3 ALL cell lines (CEM, Jurkat T, Reh) and 3 AML cell lines (HL-60, KG-1a, NB4), respectively. Independent-samples t test analysis was performed to determine statistical significance. RESULTS: Using ß-actin as reference gene, the relative expression results showed that the expression of 4 NK ligands between ALL and AML is significantly different. Specifically, the level of ULBP-2 is higher in ALL (CEM: 1, Jurkat T: 0.617, Reh: 0.246) than that in AML (HL-60: 0.000, KG-1a: 0.003, NB4: 0.000)(P = 0.047). However, the expressions of CD48, PVR(PVR-1, PVR-2) and DR4 is higher in AML (HL-60: 13.987, 4.403, 10.334, 8.711; KG-1a: 5.387, 2.900, 7.315, 4.512; NB4: 7.763, 3.248, 7.049, 6.127) than that in ALL (CEM: 1, 1, 1, 1; Jurkat T: 2.035, 1.553, 3.888, 0.449; Reh: 1.559, 0.000, 0.000, 1.304) (P = 0.044, 0.014, 0.014, 0.011). And there're no significant differences between the rest 19 NK ligands. CONCLUSIONS: ULBP-2, CD48, PVR and DR4 might play an important role in the distinct mechanisms in leukemogenesis between ALL and AML and could be potential targets for diagnosis and treatment.

[K562 cells induces apoptosis of activated NK cells in vitro].

OBJECTIVE: To investigate the apoptosis of NK cells induced by the erythroleukemia cell line K562 in vitro. METHODS: Primary NK cells isolated from the peripheral blood of healthy donors by magnetic-activated cell sorting were cultured with stem cell medium containing recombinant human interleukin-2 (rhIL-2). The NK cells and K562 cells were mixed and co-cultured at different E:T ratios for different time lengths. The apoptosis of NK cells and K562 cells were detected using PE-AnnexinV/7-AAD labeling and flow cytometry. RESULTS: The purity of isolated NK cells reached (93.99∓4.22)%. At the same E: T ratio, the apoptotic rate of NK cells induced by K562 cells increased significantly with time. As the E:T ratio reduced, the apoptotic rate of the NK cells increased and their cytotoxic activity against K562 cells was attenuated. CONCLUSION: K562 cells can induce the apoptosis of activated NK cells, which is one of the probable mechanisms of immune escape of tumors.

Imatinib induces H2AX phosphorylation and apoptosis in chronic myelogenous leukemia cells in vitro via caspase-3/Mst1 pathway.

AIM: Histone H2AX is a novel tumor suppressor and its phosphorylation at the C terminus (Ser139 and Tyr142) is required for tumor cell apoptosis. The aim of the present study was to elucidate the mechanisms underlying imatinib-induced C-terminal phosphorylation of H2AX in chronic myelogenous leukemia cells in vitro. METHODS: BCR-ABL-positive K562 cells were used. Microscopy, Western blotting and flow cytometry were used to study the signaling pathways that regulate imatinib-induced H2AX phosphorylation and the apoptotic mechanisms. RESULTS: Treatment of K562 cells with imatinib (1-8 µmol/L) induced phosphorylation of H2AX at Ser139 and Tyr142 in time- and dose-dependent manners. In contrast, imatinib at the same concentrations did not affect H2AX acetylation at Lys 5, and the acetylated H2AX maintained a higher level in the cells. Meanwhile, imatinib (1-8 µmol/L) activated caspase-3 and its downstream mammalian STE20-like kinase 1 (Mst1), and induced apoptosis of K562 cells. The caspase-3 inhibitor Z-VAD (40 µmol/L) reduced imatinib-induced H2AX phosphorylation at Ser139 and Tyr142 and blocked imatinib-induced apoptosis of K562 cells. Imatinib (4 µmol/L) induced expression of Williams-Beuren syndrome transcription factor (WSTF), but not wild-type p53-induced phosphatase 1 (Wip1) in K562 cells. CONCLUSION: The caspase-3/Mst1 pathway is required for H2AX C-terminal phosphorylation at Ser139 and Tyr142 and subsequent apoptosis in Bcr-Abl-positive K562 cells induced by imatinib.

[Veto T cells enhance engraftment allogeneic hematopoietic stem cells].

Veto activity was defined as the capacity of specifically downregulating cytotoxic T-precursor cell (CTL-p) directed against antigens of the veto cells themselves but not against third-party antigens. Many studies have shown that the most potent veto cells are CD8(+) cytotoxic T lymphocytes (CD8(+)CTLs). Effectively, CD8(+)CTLs of donor origin can facilitate engraftment of donor's stem cells by eliminating host-alloreactive T lymphocytes. In this article, effect mechanisms, depletion of GVH ex vivo, application in vivo, synergistic enhancement with rapamycin and regulatory T cells, and anti-tumor effect in the hematopoietic stem cell transplantation are summarized.

[Expression of NKG2D and NKG2A with their ligands MHC-I A/B and HLA-E in acute leukemia patients and its significance].

This study was aimed to explore the difference of NK cell receptor NKG2D and NKG2A expression on NK cells and CD3(+) T cells and their ligand MHC-I A/B (major histocompatibility complex class I-related chains A/B) and HLA-E expression in leukemia cells, as well as its immunological significance. Flow cytometry was used to detect the killing rate of NK92 cells to 8 leukemia cell lines, and the expression of NKG2D and NKG2A on NK cells and CD3(+) T cells as well as their ligand MHC-I A/B and HLA-E expression on leukemia cells. The results indicated that the NK92 showed different killing activity to different leukemia cell lines. The positive expression rate of NKG2D and NKG2A on NK cells and CD3(+) T cells in ALL patients was no significantly different from that in AML patients (p > 0.05), but positive expression rate of MHC-I A/B and HLA-E in ALL patients was obviously higher than that in AML patients (p < 0.05). It is concluded that there is difference of immune cell function between ALL and AML patients, this difference may be associated with the expression difference of NKG2D and NKG2A ligands on leukemia cells while does not associated with the killing and inhibiting receptors expressed on NK cells and CD3(+) T cells.

MAPKs and Mst1/Caspase-3 pathways contribute to H2B phosphorylation during UVB-induced apoptosis.

Apoptosis is a highly coordinated or programmed cell suicide mechanism in eukaryotes. Histone modification is associated with nuclear events in apoptotic cells. Specifically H2B phosphorylation at serine 14 (Ser14) catalyzed by Mst1 kinase has been linked to chromatin condensation during apoptosis. We report that activation of MAPKs (ERK1/2, JNK1/2 and p38) together with Mst1 and caspase-3 is required for phosphorylation of H2B (Ser14) during ultraviolet B light (UVB)-induced apoptosis. UVB can trigger activation of MAPKs and induce H2B phosphorylation at Ser14 but not acetylation in a time-dependent manner. Inhibition of ERK1/2, JNK1/2 or p38 activity blocked H2B phosphorylation (Ser14). Furthermore, caspase-3 was activated by UVB to regulate Mst1 activity, which phosphorylates H2B at Ser14, leading to chromatin condensation. Full inhibition of caspase-3 activity reduced Mst1 activation and partially inhibited H2B phosphorylation (Ser14), but ERK1/2, JNK1/2 and p38 activities were not affected. Taken together, these data revealed that H2B phosphorylation is regulated by both MAPKs and caspase-3/Mst1 pathways during UVB-induced apoptosis.