AIM: To explore whether inhibition of NF-?B by antioxidant pvrrolidine dithiocarbamate (PDTC) sensitizes leukemia cells to cytotoxic drugs and its mechanism. METHODS: The indirect immunofluorescence method and electrophoretic mobility shift assay (EMSA) were used to measure the activation of NF-?B. The apoptotic cells were evaluated by flow cytometry (FCM) and the in vitro growth inhibitory effect was performed using a MTT assay. RESULTS: EMSA showed that NF-?B was activated by daunorubicin (DNR), VP-16 and then was inhibited by PDTC in a dose-dependent manner. NF-?B activation was further verified because of subunit RelA of NF-?B locating in the nuclei. FCM analysis showed that apoptotic index of HL-60 cells was up to (8.97?0.81)%, (16.01?1.06)%, (22.96?1.33)% from (5.34?0.62)%, (10.16?0.42)%, (17.32?1.15)% after exposure of HL-60 cells to 2.5-10 mg/L VP-16 combined with PDTC. VP-16 added with PDTC produced greater growth inhibitory effect to HL-60 cells than did VP-16 or DNR only (P

Silencing ATM gene gave rise to enhanced apoptotic response to irradiation and irradiation-like chemotherapy agents, this paper explored the crucial identities of the molecular elements responsible for the enhanced apoptotic response in U937 cells mediated by silencing ATM gene. Two U937 cell mutants named U937-ASPI3K (ATM, negative) and U937-pZeosv2(+) (ATM, wild-type) were used as a cell model system to identify the critical molecule(s) responsible for the varied apoptotic response in the absence or presence of ATM gene. Apoptosis was examined by measuring concentrations of free nucleosome in U937 cells. Western blot was employed to measure nuclear protein abundance of CDC25A, CDC25B, CDC25C, total p34cdc2, p34cdc2, (Thr 161) or p34cdc2 (Thr 14, Tyr 15). RT-PCR was used to estimate CDC25 transcript levels. U937-ASPI3K exhibited an enhanced apoptotic response to lower dosage of irradiation, which could not be blocked by protein synthesis inhibitor. Protein serine-threonine phosphatase inhibitor or cyclin-dependent kinase (CDK) inhibitors, on the other hand, abolished the enhancement indicated that protein phosphorylation/dephosphorylation modification and CDK activity are required for the enhanced apoptotic response in the absence of ATM gene. Upon irradiation, p34cdc2 in U937-pZeosv2(+) was maintained in an inactive state by phosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with a dramatic decrease of nuclear CDC25A, CDC25B and CDC25C proteins. In contrast, p34cdc2 in U937-ASPI3K maintained in an active state by dephosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with constant nuclear CDC25A, CDC25B and CDC25C protein abundance before and after irradiation. The responsive decrease of nuclear CDC25 proteins occurred at the post-transcription level. Silencing ATM gene blocks the responsive decrease of nuclear CDC25 proteins, which is responsible for failure to inactivate p34cdc2 after irradiation. Active p34cdc2 and CDK2, in turn, acts as the death executors to trigger apoptosis. In summary, aberrantly activated CDK activity is the critical molecular mechanism central to enhanced apoptotic responses in the absence of ATM gene.

Objective To investigate the frequency of NPM1 mutation and its clinical significance in patients with cytogenetically normal acute myeloid leukemia (CN-AML). Methods The data of 190 patients with CN-AML were collected from Department of Hematology, Tongji Hospital between January 2008 and June 2015, and the discrepancies in clinical features and efficacy between CN-AML patients with NPM1 mutation and those without NPM1 mutation were also analyzed. Results Among the 190 CN-AML patients, NPM1 mutation was found in 44 patients (23.16 %). The proportion of bone marrow blast cells and the count of peripheral white blood cells in patients with NPM1 mutation were higher than those in patients without NPM1 mutation (75.82 % vs. 63.87 % , P <0.05; 75.7 ×109/L vs. 60.0 ×109/L, P <0.05). The rate of response (complete remission + partial remission) in patients with NPM1 mutation was also higher than that in patients without NPM1 mutation [70.09 %(22/31) vs. 56.91 %(45/79), P<0.05) ]. Conclusion NPM1 mutation is associated with higher tumor burden and higher remission rate in CN-AML patients.

Objective To analyze clinical and genetic risk factors of refractory or relapsed acute myeloid leukemia (AML) patients,and evaluate the efficacy of reinduction of chemotherapy.Methods 296 newly diagnosed AML patients,including 89 refractory or relapsed cases,were observed with clinical characteristics.And the efficiency of different reinduction chemotherapy regimens were compared.Results Compared with the non-refractory or relapsed AML,age,complex karyotype and Fms like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) gene mutations were risk factors of relapsed or refractory AML (P ＜ 0.05).Seventy-eight refractory and relapsed AML patients received reinduction therapy.The overall response rate (the complete response rate and the partial response rate) was 44.90 ％ (30/78).All reinduction regimens were divided into three categories:using the initial induction scheme or using new induction scheme including some chemotherapeutics without cross-resistance (regimen A),using the induction regimen containing medium-or high-dose cytarabine (regimen B),and using priming regimen containing of G-CSF,cytarabine,aclacinomycin or homoharringtonine (regimen C).Their overall response rate were 35.12 ％ (13/37),61.90 ％ (13/21) and 45.00 ％ (9/20),respectively,in which the overall response rate of regimen B was statistically higher than regimen A (P ＜ 0.05).Conclusions Age,complex karyotype and FLT3-ITD mutation were important causes of relapsed or refractory AML.The overall response rates were different among three different reinduction regimens.It is helpful to improve the overall response rate of reinduction therapy to use the regimen containing medium-or high-dose cytarabine,which was more suitable for young patients.For patients with poor tolerance,the priming regimen suit was more helpful to improve the overall response rate.

To evaluate the therapeutic effect of hematopoietic stem cell transplantation (HSCT), we performed HSCT in 30 patients with hematologic maligancies. Of the 30 patients, 10 underwent autologous peripheral blood stem cell transplantation (auto-PBSCT), 13 underwent myeloablative allogeneic HSCT while 7 underwent nonmyeloablative allogeneic HSCT, which were designated as autologous group, myeloablative group and nonmyeloablative group, respectively. All patients except the one who underwent cord blood transplantation, were successfully engrafted. Median time for the granulocytes > or = 0.5 x 10(9)/L and platelets > or = 20 x 10(9)/L were 12 days and 13 days respectively in autologous group, 16 days and 19 days in myeloablative group, 15 days and 12 days in nonmyeloablative group. In myeloablative group, acute graft-versus-host diseases (aGVHD) was observed in 3 patients, all of which were I-II grade. Oral mucous cGVHD was observed in 1 patient. In nonmyeloablative group, 1 patient developed intestinal aGVHD grade IV and cutaneous cGVHD was induced by donor lymphocyte infusions (DLI) in 3 patients. 1 patient had hematological relapse in autologous group. 1 patient had cytogenetic relapse in myeloablative group. In nonmyeloablative group 3 patients had cytogenetic relapse and were cured by DLI, 1 patient had hematological relapse. 4 of the 30 patients died of infection (2 patients), grade IV aGVHD (1) and relapse (1) respectively. 26 patients are still alive. 3 years overall survival (OS) and 3 years disease free survival (DFS) were 100% and 64.81% respectively in autologous group, 78.75% and 63% respectively in myeloablative group while both 66.67% in nonmyeloablative group. In conclusion, autologous group had less transplant-related complications and mortality. Active prophylaxis of relapse could significantly promote DFS. The transplant-related mortality limited DFS in myeloablative group. More relapses occurred in nonmyeloablative group, but could be cured by DLI.
China/epidemiology ; Follow-Up Studies ; Graft vs Host Disease/*epidemiology ; *Hematopoietic Stem Cell Transplantation/adverse effects ; Leukemia/*surgery ; Leukemia, Myelomonocytic, Chronic/surgery ; Leukemia, Nonlymphocytic, Acute/surgery ; Lymphoma/surgery

The effects of a novel immunosuppressive agent FTY720 on proliferation inhibition and apoptosis of acute leukemia cell lines HL-60 and U937, and the role of extracelluar regulated protein kinase (ERK) in the course of proliferation inhibition and apoptosis induced by FTY720 were studied. The proliferation inhibition rate of HL-60 and U937 cells by various concentrations of FTY720 was detected by MTT assay. Cell apoptosis was detected by DNA fragment analysis and flow cytometry. The phosphorylated ERK1/2 protein expression was observed by Western blotting. The change of intracellular distribution of ERK1/2 protein was identified by SP immunohistochemical staining. The results showed that FTY720 could inhibit the growth of HL-60 and U937 cells effectively in a dose-dependent manner. After incubation with FTY720 for 24 h, apoptosis was observed in HL-60 and U937 cells. The intracellular expression of phosphorylated ERK1/2 protein was also down-regulated and the distribution of ERK1/2 protein in cell nuclear was reduced during FTY720-induced apoptosis. So, that FTY720 inhibited ERK1/2 phosphorylation might mediate the role of FTY720-induced apoptosis and proliferation inhibition of leukemia cells.
Apoptosis ; drug effects ; Cell Division ; drug effects ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Fingolimod Hydrochloride ; HL-60 Cells ; Humans ; Immunosuppressive Agents ; pharmacology ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Phosphorylation ; Propylene Glycols ; pharmacology ; Signal Transduction ; Sphingosine ; analogs & derivatives ; U937 Cells

In order to investigate the regulative function of telomerase and phosphorylated (activated) extracellular regulated protein kinase (ERK) 1 and 2 in the leukemic cell lines HL-60 and K562 proliferation inhibition and apoptosis, three chemotherapeutic drugs Harringtonine (HRT), Vincristine (VCR) and Etoposide (Vp16) were selected as inducers. The proliferation inhibition rate was detected by MTT method, the cell cycle and cell apoptosis was analyzed by flow cytometry and the telomerase activity was detected by the telomeric repeat amplification protocol (TRAP) assay and bioluminescence analysis method. The phosphorylated ERK1/2 protein expression was detected by western blot method. The results showed that HRT, VCR and Vp16 could inhibit cell proliferation, induce apoptosis, inhibit telomerase activity and down-regulate the protein expression of phosphorylated ERK. It was suggested that ERK signal transduction pathway was involved in the down-regulation of telomerase activity and the onset of apoptosis in the leukemic cells treated by HRT, VCR and Vp16.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Division ; drug effects ; Down-Regulation ; Etoposide ; pharmacology ; HL-60 Cells ; Harringtonines ; pharmacology ; Humans ; K562 Cells ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinases ; metabolism ; Phosphorylation ; Telomerase ; metabolism ; Vincristine ; pharmacology

Silencing ATM gene gave rise to enhanced apoptotic response to irradiation and irradiation-like chemotherapy agents, this paper explored the crucial identities of the molecular elements responsible for the enhanced apoptotic response in U937 cells mediated by silencing ATM gene. Two U937 cell mutants named U937-ASPI3K (ATM, negative) and U937-pZeosv2(+) (ATM, wild-type) were used as a cell model system to identify the critical molecule(s) responsible for the varied apoptotic response in the absence or presence of ATM gene. Apoptosis was examined by measuring concentrations of free nucleosome in U937 cells. Western blot was employed to measure nuclear protein abundance of CDC25A, CDC25B, CDC25C, total p34cdc2, p34cdc2, (Thr 161) or p34cdc2 (Thr 14, Tyr 15). RT-PCR was used to estimate CDC25 transcript levels. U937-ASPI3K exhibited an enhanced apoptotic response to lower dosage of irradiation, which could not be blocked by protein synthesis inhibitor. Protein serine-threonine phosphatase inhibitor or cyclin-dependent kinase (CDK) inhibitors, on the other hand, abolished the enhancement indicated that protein phosphorylation/dephosphorylation modification and CDK activity are required for the enhanced apoptotic response in the absence of ATM gene. Upon irradiation, p34cdc2 in U937-pZeosv2(+) was maintained in an inactive state by phosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with a dramatic decrease of nuclear CDC25A, CDC25B and CDC25C proteins. In contrast, p34cdc2 in U937-ASPI3K maintained in an active state by dephosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with constant nuclear CDC25A, CDC25B and CDC25C protein abundance before and after irradiation. The responsive decrease of nuclear CDC25 proteins occurred at the post-transcription level. Silencing ATM gene blocks the responsive decrease of nuclear CDC25 proteins, which is responsible for failure to inactivate p34cdc2 after irradiation. Active p34cdc2 and CDK2, in turn, acts as the death executors to trigger apoptosis. In summary, aberrantly activated CDK activity is the critical molecular mechanism central to enhanced apoptotic responses in the absence of ATM gene.
Apoptosis ; drug effects ; genetics ; radiation effects ; Ataxia Telangiectasia Mutated Proteins ; CDC2 Protein Kinase ; metabolism ; Cell Cycle Proteins ; Cyclin-Dependent Kinases ; metabolism ; DNA-Binding Proteins ; Gene Silencing ; drug effects ; radiation effects ; Humans ; Protein-Serine-Threonine Kinases ; genetics ; Tumor Suppressor Proteins ; U937 Cells ; cdc25 Phosphatases ; metabolism

Autophagy plays an important dual role in the occurrence and development of acute leukemia, inducing the apoptosis of leukemia cells to suppress the development of acute leukemia, and protecting the leukemia cells to sustain the survival and to resist the apoptosis induced by chemotherapy drugs. Some studies have showed that the drug sensitivity of acute leukemia cells can be improved by regulating autophagy to induce the apoptosis of leukemia cells, and thus, regulating autophagy is expected to be an effective therapeutic strategy of refractory/relapsed acute leukemia. This article reviews the recent progress of autophagy and acute leukemia treatment.

Acute myeloid leukemia (AML) is considered to be an irreversible change of gene function caused by certain genetic changes, resulting in abnormal proliferation, differentiation disorder, and abnormal apoptosis of leukemia cells, leading to the occurrence and development of leukemia. Epigenetics refers to the change of heritable gene expression but the gene does not change in sequence. A large number of studies have shown that the pathogenesis of AML is closely related to the regulation of epigenetics. The regulation of epigenetic modification in the cellular metabolism, immune microenvironment and immune response of AML has been received increasing attention. This review will describe the regulation of epigenetics in the cellular metabolism, immune microenvironment and immune response of AML and the advances in the targeted intervention measures.