Background Homoharringtonine (HHT) is a cephalotaxine ester derived from an evergreen tree found wildely throughout southern China, which has antileukemic activities against a variety of acute myeloid leukemic cells. ...Background Homoharringtonine (HHT) is a cephalotaxine ester derived from an evergreen tree found wildely throughout southern China, which has antileukemic activities against a variety of acute myeloid leukemic cells. For the sake of illustrating the mechanisms of HHT in the treatment of leukemia, we assessed the effect of HHT on the apoptosis of human chronic myeloid leukemic cell line K562.Methods The apoptosis of K562 cells induced by HHT was analyzed by transmission electron microscopy, agarose gel electrophoresis of DNA, flow cytometry and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick labeling.Results Characteristic apoptosis-related features emerged in K562 cells after exposed to HHT at a concentration 0.05-100 μg/ml. Transmission electron microscopy of HHT treated K562 cells displayed chromatin condensation and aggregation under the nuclear membrane, nuclear fragmentation and apoptosis body formation. Typical DNA ladder in agarose gel electrophoresis was observed in the cells exposed to HHT. The cell cycle analysis measured by flow cytometry showed G1 phase cells decreased with the increase of S phase cells while apoptosis was induced by HHT in K562 cells. The percentage of apoptotic cells in K562 cells treated with 50 μg/ml of HHT decreased significantly when pretreated with 1 μg/ml of cycloheximide, 0.05 μg/ml of Actinomycin D respectively.Conclusions HHT has apoptotic effects on K562 cells. The HHT induced apoptosis mainly of the cells in G1 phase and this process required RNA transcription and protein synthesis.展开更多
This report characterizes the J6-1 cell line derived from a Chinese acute myelomonocytic leukemia patient and previously reported to be associated with EBV. These studies showed that J6-1 cells were also infected with...This report characterizes the J6-1 cell line derived from a Chinese acute myelomonocytic leukemia patient and previously reported to be associated with EBV. These studies showed that J6-1 cells were also infected with HHV-6 as demonstrate at the DNA level by PCR and Southern blot hybridization and by expression of HHV-6 early membrane antigen on the J6-1 cell surface. Further characterization showed J6-1 was co-infected with EBV type 2. Generally, cells infected with EBV type 2 do not grow well in vitro. However, J6-1 , although difficult to maintain in vitro, has been grown for 15 years. Possibly, co-infection with HHV6 confers this property. In this regard, J6-1 cells exhibited density dependent growth which could be inhibited with an anti-HHV-6-MA monoclonal antibody(MAb). In contrast, anti-HHV-6-VCA MAb stimulated the J6-1 cell proliferation. Electron microscopic analysis showed that, morphologically, there were two types of J6-1 cell, one with lymphoblastoid features and one with a monocytoid appearance. Accordingly, the flow profile of the J6-1 cell line showed heterogeneity. with two populations comprised of CD15-, CD19+ cells with low light scatter(small cells) and a population with greater light scatter(larger cells) which was CD15+ , CD19+. The population was negative for progenitor cell markers(CD33, 34 ), and T cell markers. Southern analysis showed no T cell receptor rearrangement, however there was a clonal JH and kappa light chain expressing population. Glycocytochemical analysis showed several endogenous lectin receptors on the J6-1 cell surface: BSA-Xylose, BSA-Rhamnose, BSAGal. BSA-Lac. This cell line shares many characteristics with other monocytic/ lymphoblastoid cell lines isolated elsewhere and provides circumstantial evidence linking Herpes viruses, as least as co- factors,to leukemia cell growth.展开更多
Chronic myeloid leukemia(CML)is a myeloproliferative disease characterized by the overproduction of granulocytes,which leads to high white blood cell counts and splenomegaly in patients.Based on clinical symptoms and ...Chronic myeloid leukemia(CML)is a myeloproliferative disease characterized by the overproduction of granulocytes,which leads to high white blood cell counts and splenomegaly in patients.Based on clinical symptoms and laboratory findings,CML is classified into three clinical phases,often starting with a chronic phase,progressing to an accelerated phase and ultimately ending in a terminal phase called blast crisis.Blast crisis phase of CML is clinically similar to an acute leukemia;in particular,B-cell acute lymphoblastic leukemia(B-ALL)is a severe form of acute leukemia in blast crisis,and there is no effective therapy for it yet.CML is induced by the BCR-ABL oncogene,whose gene product is a BCR-ABL tyrosine kinase.Currently,inhibition of BCR-ABL kinase activity by its kinase inhibitor such as imatinib mesylate(Gleevec)is a major therapeutic strategy for CML.However,the inability of BCR-ABL kinase inhibitors to completely kill leukemia stem cells(LSCs)indicates that these kinase inhibitors are unlikely to cure CML.In addition,drug resistance due to the development of BCRABL mutations occurs before and during treatment of CML with kinase inhibitors.A critical issue to resolve this problem is to fully understand the biology of LSCs,and to identify key genes that play significant roles in survival and self-renewal of LSCs.In this review,we will focus on LSCs in CML by summarizing and discussing available experimental results,including the original studies from our own laboratory.展开更多
Objective To summarize the risk stratification and current treatment strategies for acute myeloid leukemia （AML） and discuss the role of emerging novel agents that might be applied in future clinical trials.Data sou...Objective To summarize the risk stratification and current treatment strategies for acute myeloid leukemia （AML） and discuss the role of emerging novel agents that might be applied in future clinical trials.Data sources The data in this article were collected from PubMed database with relevant English articles published from 1991 to 2009.Study selection Articles regarding the risk stratification and therapeutic options of AML, as well as the characteristics of leukemic stem cells were selected.Results AML is a heterogeneous disease with variable clinical outcome dependent on several prognostic factors,including age, cytogenetics and molecular markers. The advances in the understanding of AML pathogenesis and development will generate potential novel agents that might improve the treatment results of standard chemotherapy.Conclusion Deeper insight into the multiple transforming events of AML may aid us in designing combinations of small molecule inhibitors based on the individual patient characteristics.展开更多
Objective To investigate the retrovirus mediated transfer and expression of multidrug resistance gene (mdr1) in hematopoietic cells and to develop a model for studying the possible reversal of the MDR mediated phen...Objective To investigate the retrovirus mediated transfer and expression of multidrug resistance gene (mdr1) in hematopoietic cells and to develop a model for studying the possible reversal of the MDR mediated phenotype Methods A retroviral vector HaMDR expressing the human mdr1 gene was packaged by PA317 cells with a titer of up to 8 5×10 5CFU/ml K562 leukemia cells were infected with MDR retrovirus, and transfectant K562/MDR cells were generated The integration and expression of the exogenous mdr1 gene in K562/MDR cells were determined by polymerase chain reaction and flow cytometry The reversal ability of P glycoprotein (P gp) antagonists was analyzed by in vitro drug sensitivity, accumulation and efflux of rhodamine 123 (Rh123) in this model Results Transduction with amphotropic MDR retrovirus resulted in integration and expression of the mdr1 gene in the resistant cells, where an aberrant splicing transcript of the mdr1 gene was found The K562/MDR cells displayed a classic MDR phenotype with a 41-78 fold resistance to vincristine and colchicine in comparison with parental K562 cells The drug sensitivity of K562/MDR cells to vincristine can be completely restored by cyclosporin A (CsA, 2?mg/L) and Cremophor EL (CRE 132?mg/L), either individually or in combination ( P <0 05) CsA (3 ?mg/L) can block the efflux pump function of P gp shown by the significantly increased accumulation and efflux reduction of Rh123 in K562/MDR cells Conclusions Retroviral vector HaMDR allows transfection with high level expression of the mdr1 gene in human myeloid progenitor cells K562 The transfected K562/MDR provides a simple, sensitive model for developing antagonists of P gp and studying their mechanism of action展开更多
Objective To evaluate the effect of human telomerase reverse transcriptase (hTERT) gene antisense oligodeoxynucleotide (ASODN) ontelomerase activity in K562 cells.Methods Telomerase activity was determined by polymera...Objective To evaluate the effect of human telomerase reverse transcriptase (hTERT) gene antisense oligodeoxynucleotide (ASODN) ontelomerase activity in K562 cells.Methods Telomerase activity was determined by polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA) in K562 cellstreated with ASODN and hTERT mRNA expression was detected by reverse transcriptase polymerase chain reaction (RT-PCR).Results The hTERT mRNA level was decreased, and teloraerase activity was significantly inhibited when the K562 cells were treated withASODN for 48 h.Conclusion It is suggested that hTERT ASODN might specifically inhibit telomerase activity of K562 cells at translation level, and it isfurther proved that hTERT gene has significant correlation with telomerase activity.展开更多
OBJECTIVE: To study the effect of all-trans retinoic acid (ATRA) and arsenic troxide (As2O3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia (APL) cells in vivo and in ...OBJECTIVE: To study the effect of all-trans retinoic acid (ATRA) and arsenic troxide (As2O3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia (APL) cells in vivo and in vitro. METHODS: PCA from freshly isolated APL blasts from APL patients treated with ATRA or As2O3 was detected using a one-stage clotting assay. TF antigen was detected by ELISA and TF mRNA by RT-PCR. The maturation sensitive (NB4) or resistant subclones (NB4-R1) of the promyelocytic NB4 cell line, as well as U937 cells infected with pMSCV-PML-RARa treated with or without ATRA or As2O3, were also examined. RESULTS: Both ATRA and As2O3 can down-regulate the TF antigen, its mRNA transcription and membrane PCA of APL cells in vivo and in vitro, in a time-dependent manner. The TF antigen level in PML-RARa + U937 cells was significantly higher than that in U937 cells infected with retrovirus vector. Both ATRA and As2O3 can also down-regulate the TF antigen in U937 cells transfected with or without PML-RARa. CONCLUSION: Tissue factor expression and PCA in APL cells may be down-regulated by ATRA and As2O3. By down-regulating TF expression, As2O3 might also be used to improve the DIC-related hemorrhage in APL. Our data indicate that elevated TF antigen in PML-RARa + U937 may be related to the fusion protein PML-RARa. The down-regulating effect of ATRA and As2O3 on TF expression in U937 cells might not involve this fusion protein.展开更多
Objective： To explore the effects of Danshen Injection （丹参注射液） on inhibition proliferation, inducing apoptosis and its possible mechanisms on human erythroid leukemic （HEL） cells. Methods： The commercial Ch...Objective： To explore the effects of Danshen Injection （丹参注射液） on inhibition proliferation, inducing apoptosis and its possible mechanisms on human erythroid leukemic （HEL） cells. Methods： The commercial Chinese patent medicine of Danshen Injection was extracted and isolated from Chinese herb of Salvia miltiorrhiza bung. The inhibition effects of proliferation were assayed by 3-（4,5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （M＇l-r） method in HEL cells treated by Danshen Injection at various concentrations for 48 h. The cellular apoptosis was observed in morphology, analyzed by flow cytometry with annexin V and propidium iodide （PI） staining, and examined by DNA degradation ladder on agarose gel electrophoresis. Meanwhile, the expression levels of mutant Janus kinasez （JAK2） gene and phosphorylation-JAK2 （P-JAK2） protein were detected by allele specific-polymerase chain reaction and Western blot. ]Results： The proliferation of HEL cells was effectively inhibited by Danshen Injection in a dose-dependent manner, with suppression rates from 19.46 ± 2.31% to 50.20 ± 5.21%. Typical apoptosis cells was observed in Danshen Injection treated HEL cells, the rates of annexin V positive cells increased obviously in a dose-dependent manner, as well as the DNA degradation ladder of apoptosis revealed on gel electrophoresis. The expression levels of mutant JAK2 gene and P-JAK2 protein reduced gradually with increasing dosage of Danshen injection. Conclusion： Danshen Injection could not only significantly inhibit the proliferation, but also induce apoptosis in HEL cells; down-regulation of the mutant JAK2 gene and P-JAK2 protein expressions are probably one of its molecular mechanisms.展开更多
To investigate whether the Bcl- 2 gene family is involved in m odulating mechanism of apoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL - 6 0 cell line and primary acute m y...To investigate whether the Bcl- 2 gene family is involved in m odulating mechanism of apoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL - 6 0 cell line and primary acute m yelogenous leukem ic cells,the Bcl- 2 family member Mcl- 1,Bax and Bak and cell cycle proteins including P2 7kipl,P2 1wafl,cyclin D3and p Rbp- were selected and their ex- pression detected by SABC imm uno- histochem ical stain m ethod.The attitude of sub- G1 peak in DNA histogram was determined by FCM.The TU NEL positive cell percentage was identified by term inal deoxynucleotidyl transferase (Td T ) - m ediated Biotin d U NP end labeling technique.It was found that when HL - 6 0 cells were treated with 2 5μm ol/ L curcumin for 2 4 h,the expression level of Mcl- 1was down- regulated,but that of Bax and Bak up- regulated time- dependently.There was significant difference in the expression level of Mcl- 1,Bax and Bak between the curcumin- treated groups and control group(P<0 .0 5 - 0 .0 1) .At the sam e time,curcumin had no effect on progress of cell cycle in prim aty acute m yelogenous leukemia at newly diagnosis,but could in- crease the peak of Sub- G1 (P<0 .0 5 ) ,and down- regulate the expression of Mcl- 1and up- regulate the expression of Bax and Bak with the difference being statistically significant.The expression of P2 7kipl,P2 1wafl and p Rbp- were elevated and thatof cyclin D3decreased in the presence of curcum in. These findings suggested thatthe Bcl- 2 gene fam ily indeed participated in the regulatory process of apoptosis induced by curcumin in HL - 6 0 cells and AML cells.Curcumin can induce apoptosis of primary acute myelogenous leukemic cells and disturb cell cycle progression of HL - 6 0 cells.The m echanism appeared to be m ediated by perturbing G0 / G1 phases checkpoints which associated with up- regulation of P2 7kipl,P2 1wafl and p Rbp- expression,and down- regulation of cyclin D3.展开更多
Bone marrow microenvironment (BMM) is the main sanctuary of leukemic stem cells (LSCs) and protects these cells against conventional therapies. However, it may open up an opportunity to target LSCs by breaking the clo...Bone marrow microenvironment (BMM) is the main sanctuary of leukemic stem cells (LSCs) and protects these cells against conventional therapies. However, it may open up an opportunity to target LSCs by breaking the close connection between LSCs and the BMM. The elimination of LSCs is of high importance, since they follow cancer stem cell theory as a part of this population. Based on cancer stem cell theory, a cell with stem cell-like features stands at the apex of the hierarchy and produces a heterogeneous population and governs the disease. Secretion of cytokines, chemokines, and extracellular vesicles, whether through autocrine or paracrine mechanisms by activation of downstream signaling pathways in LSCs, favors their persistence and makes the BMM less hospitable for normal stem cells. While all details about the interactions of the BMM and LSCs remain to be elucidated, some clinical trials have been designed to limit these reciprocal interactions to cure leukemia more effectively. In this review, we focus on chronic myeloid leukemia and acute myeloid leukemia LSCs and their milieu in the bone marrow, how to segregate them from the normal compartment, and finally the possible ways to eliminate these cells.展开更多
Objective To explore the effects of bufalin on inhibiting proliferation, up-regulating methylation of Wilm’ tumor 1 gene (WT1) as well as its possible mechanisms in human erythroid leukemic (HEL) cells. Methods The H...Objective To explore the effects of bufalin on inhibiting proliferation, up-regulating methylation of Wilm’ tumor 1 gene (WT1) as well as its possible mechanisms in human erythroid leukemic (HEL) cells. Methods The HEL cells were treated with bufalin at various concentrations to observe cellular morphology, proliferation assay and cell cycle. The mRNA and protein expression levels of WT1 were detected by reverse transcription polymerase chain reaction (RT-PCR), Western blot and immunocytochemistry, DNA methylation of WT1 and protein expression levels of DNA methyltransferase 3a (DNMT3a) and DNMT3b were analyzed by methylation-specific PCR, and Western blot respectively. Results The bufalin was effective to inhibit proliferation of HEL cells in a dose-dependent manner, their suppression rates were from 23.4%±2.1% to 87.2%±5.4% with an half maximal inhibit concentration (IC<sub>50</sub>) of 0.046 μmol/L. Typical apoptosis morphology was observed in bufalin-treated HEL cells. The proliferation index of cell cycle decreased from 76.4%±1.9% to 49.7%±1.3%. The expression levels of WT1 mRNA and its protein reduced gradually with increasing doses of bufalin, meanwhile, the methylation status of WT1 gene changed from unmethylated into partially or totally methylated. While, the expression levels of DNMT3a and DNMT3b protein gradually increased by bufalin treatment in a dose-dependent manner. Conclusions Bufalin can not only significantly inhibit the proliferation of HEL cells and arrest cell cycle at G<sub>0</sub>/G<sub>1</sub> phase, but also induce cellular apoptosis and down-regulate the expression level of WT1. Our results provide the evidence of bufalin for anti-leukemia, its mechanism may involve in increasing WT1 methylation status which is related to the up-regulation of DNMT3a and DNMT3b proteins in erythroid leukemic HEL cells.展开更多
BACKGROUND Accumulating evidence demonstrates that autoimmune hematopoietic failure and myeloid neoplasms have an intrinsic relationship with regard to clonal hematopoiesis and disease evolution.In approximately 10%-1...BACKGROUND Accumulating evidence demonstrates that autoimmune hematopoietic failure and myeloid neoplasms have an intrinsic relationship with regard to clonal hematopoiesis and disease evolution.In approximately 10%-15%of patients with severe aplastic anemia(SAA),the disease phenotype is transformed into myeloid neoplasms following antithymocyte globulin plus cyclosporine-based immunosuppressive therapy.In some of these patients,myeloid neoplasms appear during or shortly after immunosuppressive therapy.Leukemic transformation in SAA patients during anti-tuberculosis treatment has not been reported.CASE SUMMARY A middle-aged Chinese female had a 6-year history of non-SAA and a 2-year history of paroxysmal nocturnal hemoglobinuria(PNH).With aggravation of systemic inflammatory symptoms,severe pancytopenia developed,and her hemoglobinuria disappeared.Laboratory findings in cytological,immunological and cytogenetic analyses of bone marrow samples met the diagnostic criteria for“SAA.”Definitive diagnosis of disseminated tuberculosis was made in the search for infectious niches.Remarkable improvement in hematological parameters was achieved within 1 mo of anti-tuberculosis treatment,and complete hematological remission was achieved within 4 mo of treatment.Frustratingly,the hematological response lasted for only 3 mo,and pancytopenia reemerged.At this time,cytological findings(increased bone marrow cellularity and an increased percentage of myeloblasts that accounted for 16.0%of all nucleated hematopoietic cells),immunological findings(increased percentage of cluster of differentiation 34+cells that accounted for 12.28%of all nucleated hematopoietic cells)and molecular biological findings(identification of somatic mutations in nucleophosmin-1 and casitas B-lineage lymphoma genes)revealed that“SAA”had transformed into acute myeloid leukemia with mutated nucleophosmin-1.The transformation process suggested that the leukemic clones were preexistent but were suppressed in the PNH and SAA stages,as development of sy展开更多
文摘Background Homoharringtonine (HHT) is a cephalotaxine ester derived from an evergreen tree found wildely throughout southern China, which has antileukemic activities against a variety of acute myeloid leukemic cells. For the sake of illustrating the mechanisms of HHT in the treatment of leukemia, we assessed the effect of HHT on the apoptosis of human chronic myeloid leukemic cell line K562.Methods The apoptosis of K562 cells induced by HHT was analyzed by transmission electron microscopy, agarose gel electrophoresis of DNA, flow cytometry and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick labeling.Results Characteristic apoptosis-related features emerged in K562 cells after exposed to HHT at a concentration 0.05-100 μg/ml. Transmission electron microscopy of HHT treated K562 cells displayed chromatin condensation and aggregation under the nuclear membrane, nuclear fragmentation and apoptosis body formation. Typical DNA ladder in agarose gel electrophoresis was observed in the cells exposed to HHT. The cell cycle analysis measured by flow cytometry showed G1 phase cells decreased with the increase of S phase cells while apoptosis was induced by HHT in K562 cells. The percentage of apoptotic cells in K562 cells treated with 50 μg/ml of HHT decreased significantly when pretreated with 1 μg/ml of cycloheximide, 0.05 μg/ml of Actinomycin D respectively.Conclusions HHT has apoptotic effects on K562 cells. The HHT induced apoptosis mainly of the cells in G1 phase and this process required RNA transcription and protein synthesis.
文摘This report characterizes the J6-1 cell line derived from a Chinese acute myelomonocytic leukemia patient and previously reported to be associated with EBV. These studies showed that J6-1 cells were also infected with HHV-6 as demonstrate at the DNA level by PCR and Southern blot hybridization and by expression of HHV-6 early membrane antigen on the J6-1 cell surface. Further characterization showed J6-1 was co-infected with EBV type 2. Generally, cells infected with EBV type 2 do not grow well in vitro. However, J6-1 , although difficult to maintain in vitro, has been grown for 15 years. Possibly, co-infection with HHV6 confers this property. In this regard, J6-1 cells exhibited density dependent growth which could be inhibited with an anti-HHV-6-MA monoclonal antibody(MAb). In contrast, anti-HHV-6-VCA MAb stimulated the J6-1 cell proliferation. Electron microscopic analysis showed that, morphologically, there were two types of J6-1 cell, one with lymphoblastoid features and one with a monocytoid appearance. Accordingly, the flow profile of the J6-1 cell line showed heterogeneity. with two populations comprised of CD15-, CD19+ cells with low light scatter(small cells) and a population with greater light scatter(larger cells) which was CD15+ , CD19+. The population was negative for progenitor cell markers(CD33, 34 ), and T cell markers. Southern analysis showed no T cell receptor rearrangement, however there was a clonal JH and kappa light chain expressing population. Glycocytochemical analysis showed several endogenous lectin receptors on the J6-1 cell surface: BSA-Xylose, BSA-Rhamnose, BSAGal. BSA-Lac. This cell line shares many characteristics with other monocytic/ lymphoblastoid cell lines isolated elsewhere and provides circumstantial evidence linking Herpes viruses, as least as co- factors,to leukemia cell growth.
文摘Chronic myeloid leukemia(CML)is a myeloproliferative disease characterized by the overproduction of granulocytes,which leads to high white blood cell counts and splenomegaly in patients.Based on clinical symptoms and laboratory findings,CML is classified into three clinical phases,often starting with a chronic phase,progressing to an accelerated phase and ultimately ending in a terminal phase called blast crisis.Blast crisis phase of CML is clinically similar to an acute leukemia;in particular,B-cell acute lymphoblastic leukemia(B-ALL)is a severe form of acute leukemia in blast crisis,and there is no effective therapy for it yet.CML is induced by the BCR-ABL oncogene,whose gene product is a BCR-ABL tyrosine kinase.Currently,inhibition of BCR-ABL kinase activity by its kinase inhibitor such as imatinib mesylate(Gleevec)is a major therapeutic strategy for CML.However,the inability of BCR-ABL kinase inhibitors to completely kill leukemia stem cells(LSCs)indicates that these kinase inhibitors are unlikely to cure CML.In addition,drug resistance due to the development of BCRABL mutations occurs before and during treatment of CML with kinase inhibitors.A critical issue to resolve this problem is to fully understand the biology of LSCs,and to identify key genes that play significant roles in survival and self-renewal of LSCs.In this review,we will focus on LSCs in CML by summarizing and discussing available experimental results,including the original studies from our own laboratory.
文摘Objective To summarize the risk stratification and current treatment strategies for acute myeloid leukemia （AML） and discuss the role of emerging novel agents that might be applied in future clinical trials.Data sources The data in this article were collected from PubMed database with relevant English articles published from 1991 to 2009.Study selection Articles regarding the risk stratification and therapeutic options of AML, as well as the characteristics of leukemic stem cells were selected.Results AML is a heterogeneous disease with variable clinical outcome dependent on several prognostic factors,including age, cytogenetics and molecular markers. The advances in the understanding of AML pathogenesis and development will generate potential novel agents that might improve the treatment results of standard chemotherapy.Conclusion Deeper insight into the multiple transforming events of AML may aid us in designing combinations of small molecule inhibitors based on the individual patient characteristics.
文摘Objective To investigate the retrovirus mediated transfer and expression of multidrug resistance gene (mdr1) in hematopoietic cells and to develop a model for studying the possible reversal of the MDR mediated phenotype Methods A retroviral vector HaMDR expressing the human mdr1 gene was packaged by PA317 cells with a titer of up to 8 5×10 5CFU/ml K562 leukemia cells were infected with MDR retrovirus, and transfectant K562/MDR cells were generated The integration and expression of the exogenous mdr1 gene in K562/MDR cells were determined by polymerase chain reaction and flow cytometry The reversal ability of P glycoprotein (P gp) antagonists was analyzed by in vitro drug sensitivity, accumulation and efflux of rhodamine 123 (Rh123) in this model Results Transduction with amphotropic MDR retrovirus resulted in integration and expression of the mdr1 gene in the resistant cells, where an aberrant splicing transcript of the mdr1 gene was found The K562/MDR cells displayed a classic MDR phenotype with a 41-78 fold resistance to vincristine and colchicine in comparison with parental K562 cells The drug sensitivity of K562/MDR cells to vincristine can be completely restored by cyclosporin A (CsA, 2?mg/L) and Cremophor EL (CRE 132?mg/L), either individually or in combination ( P <0 05) CsA (3 ?mg/L) can block the efflux pump function of P gp shown by the significantly increased accumulation and efflux reduction of Rh123 in K562/MDR cells Conclusions Retroviral vector HaMDR allows transfection with high level expression of the mdr1 gene in human myeloid progenitor cells K562 The transfected K562/MDR provides a simple, sensitive model for developing antagonists of P gp and studying their mechanism of action
基金Science and Technology of Guangzhou City (2001-Z-037-01)Guangdong Province (99M1204G)
文摘Objective To evaluate the effect of human telomerase reverse transcriptase (hTERT) gene antisense oligodeoxynucleotide (ASODN) ontelomerase activity in K562 cells.Methods Telomerase activity was determined by polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA) in K562 cellstreated with ASODN and hTERT mRNA expression was detected by reverse transcriptase polymerase chain reaction (RT-PCR).Results The hTERT mRNA level was decreased, and teloraerase activity was significantly inhibited when the K562 cells were treated withASODN for 48 h.Conclusion It is suggested that hTERT ASODN might specifically inhibit telomerase activity of K562 cells at translation level, and it isfurther proved that hTERT gene has significant correlation with telomerase activity.
文摘OBJECTIVE: To study the effect of all-trans retinoic acid (ATRA) and arsenic troxide (As2O3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia (APL) cells in vivo and in vitro. METHODS: PCA from freshly isolated APL blasts from APL patients treated with ATRA or As2O3 was detected using a one-stage clotting assay. TF antigen was detected by ELISA and TF mRNA by RT-PCR. The maturation sensitive (NB4) or resistant subclones (NB4-R1) of the promyelocytic NB4 cell line, as well as U937 cells infected with pMSCV-PML-RARa treated with or without ATRA or As2O3, were also examined. RESULTS: Both ATRA and As2O3 can down-regulate the TF antigen, its mRNA transcription and membrane PCA of APL cells in vivo and in vitro, in a time-dependent manner. The TF antigen level in PML-RARa + U937 cells was significantly higher than that in U937 cells infected with retrovirus vector. Both ATRA and As2O3 can also down-regulate the TF antigen in U937 cells transfected with or without PML-RARa. CONCLUSION: Tissue factor expression and PCA in APL cells may be down-regulated by ATRA and As2O3. By down-regulating TF expression, As2O3 might also be used to improve the DIC-related hemorrhage in APL. Our data indicate that elevated TF antigen in PML-RARa + U937 may be related to the fusion protein PML-RARa. The down-regulating effect of ATRA and As2O3 on TF expression in U937 cells might not involve this fusion protein.
基金Supported by Zhejiang Province Administration of Traditional Chinese Medicine(No.2010ZA120)Zhejiang Provincial Natural Science Foundation of China(No.Y207632)
文摘Objective： To explore the effects of Danshen Injection （丹参注射液） on inhibition proliferation, inducing apoptosis and its possible mechanisms on human erythroid leukemic （HEL） cells. Methods： The commercial Chinese patent medicine of Danshen Injection was extracted and isolated from Chinese herb of Salvia miltiorrhiza bung. The inhibition effects of proliferation were assayed by 3-（4,5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （M＇l-r） method in HEL cells treated by Danshen Injection at various concentrations for 48 h. The cellular apoptosis was observed in morphology, analyzed by flow cytometry with annexin V and propidium iodide （PI） staining, and examined by DNA degradation ladder on agarose gel electrophoresis. Meanwhile, the expression levels of mutant Janus kinasez （JAK2） gene and phosphorylation-JAK2 （P-JAK2） protein were detected by allele specific-polymerase chain reaction and Western blot. ]Results： The proliferation of HEL cells was effectively inhibited by Danshen Injection in a dose-dependent manner, with suppression rates from 19.46 ± 2.31% to 50.20 ± 5.21%. Typical apoptosis cells was observed in Danshen Injection treated HEL cells, the rates of annexin V positive cells increased obviously in a dose-dependent manner, as well as the DNA degradation ladder of apoptosis revealed on gel electrophoresis. The expression levels of mutant JAK2 gene and P-JAK2 protein reduced gradually with increasing dosage of Danshen injection. Conclusion： Danshen Injection could not only significantly inhibit the proliferation, but also induce apoptosis in HEL cells; down-regulation of the mutant JAK2 gene and P-JAK2 protein expressions are probably one of its molecular mechanisms.
基金This project wassupport by a grantfrom National NaturalSciences Foundation ofChina(No. 39770 934)
文摘To investigate whether the Bcl- 2 gene family is involved in m odulating mechanism of apoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL - 6 0 cell line and primary acute m yelogenous leukem ic cells,the Bcl- 2 family member Mcl- 1,Bax and Bak and cell cycle proteins including P2 7kipl,P2 1wafl,cyclin D3and p Rbp- were selected and their ex- pression detected by SABC imm uno- histochem ical stain m ethod.The attitude of sub- G1 peak in DNA histogram was determined by FCM.The TU NEL positive cell percentage was identified by term inal deoxynucleotidyl transferase (Td T ) - m ediated Biotin d U NP end labeling technique.It was found that when HL - 6 0 cells were treated with 2 5μm ol/ L curcumin for 2 4 h,the expression level of Mcl- 1was down- regulated,but that of Bax and Bak up- regulated time- dependently.There was significant difference in the expression level of Mcl- 1,Bax and Bak between the curcumin- treated groups and control group(P<0 .0 5 - 0 .0 1) .At the sam e time,curcumin had no effect on progress of cell cycle in prim aty acute m yelogenous leukemia at newly diagnosis,but could in- crease the peak of Sub- G1 (P<0 .0 5 ) ,and down- regulate the expression of Mcl- 1and up- regulate the expression of Bax and Bak with the difference being statistically significant.The expression of P2 7kipl,P2 1wafl and p Rbp- were elevated and thatof cyclin D3decreased in the presence of curcum in. These findings suggested thatthe Bcl- 2 gene fam ily indeed participated in the regulatory process of apoptosis induced by curcumin in HL - 6 0 cells and AML cells.Curcumin can induce apoptosis of primary acute myelogenous leukemic cells and disturb cell cycle progression of HL - 6 0 cells.The m echanism appeared to be m ediated by perturbing G0 / G1 phases checkpoints which associated with up- regulation of P2 7kipl,P2 1wafl and p Rbp- expression,and down- regulation of cyclin D3.
文摘Bone marrow microenvironment (BMM) is the main sanctuary of leukemic stem cells (LSCs) and protects these cells against conventional therapies. However, it may open up an opportunity to target LSCs by breaking the close connection between LSCs and the BMM. The elimination of LSCs is of high importance, since they follow cancer stem cell theory as a part of this population. Based on cancer stem cell theory, a cell with stem cell-like features stands at the apex of the hierarchy and produces a heterogeneous population and governs the disease. Secretion of cytokines, chemokines, and extracellular vesicles, whether through autocrine or paracrine mechanisms by activation of downstream signaling pathways in LSCs, favors their persistence and makes the BMM less hospitable for normal stem cells. While all details about the interactions of the BMM and LSCs remain to be elucidated, some clinical trials have been designed to limit these reciprocal interactions to cure leukemia more effectively. In this review, we focus on chronic myeloid leukemia and acute myeloid leukemia LSCs and their milieu in the bone marrow, how to segregate them from the normal compartment, and finally the possible ways to eliminate these cells.
基金Supported by National Natural Science Foundation of China(No.81403223)Zhejiang Provincial Natural Science Foundation of China(No.LQ14H290003)Science and Technology Foundation of Zhejiang Province(No.2015C33173)
文摘Objective To explore the effects of bufalin on inhibiting proliferation, up-regulating methylation of Wilm’ tumor 1 gene (WT1) as well as its possible mechanisms in human erythroid leukemic (HEL) cells. Methods The HEL cells were treated with bufalin at various concentrations to observe cellular morphology, proliferation assay and cell cycle. The mRNA and protein expression levels of WT1 were detected by reverse transcription polymerase chain reaction (RT-PCR), Western blot and immunocytochemistry, DNA methylation of WT1 and protein expression levels of DNA methyltransferase 3a (DNMT3a) and DNMT3b were analyzed by methylation-specific PCR, and Western blot respectively. Results The bufalin was effective to inhibit proliferation of HEL cells in a dose-dependent manner, their suppression rates were from 23.4%±2.1% to 87.2%±5.4% with an half maximal inhibit concentration (IC<sub>50</sub>) of 0.046 μmol/L. Typical apoptosis morphology was observed in bufalin-treated HEL cells. The proliferation index of cell cycle decreased from 76.4%±1.9% to 49.7%±1.3%. The expression levels of WT1 mRNA and its protein reduced gradually with increasing doses of bufalin, meanwhile, the methylation status of WT1 gene changed from unmethylated into partially or totally methylated. While, the expression levels of DNMT3a and DNMT3b protein gradually increased by bufalin treatment in a dose-dependent manner. Conclusions Bufalin can not only significantly inhibit the proliferation of HEL cells and arrest cell cycle at G<sub>0</sub>/G<sub>1</sub> phase, but also induce cellular apoptosis and down-regulate the expression level of WT1. Our results provide the evidence of bufalin for anti-leukemia, its mechanism may involve in increasing WT1 methylation status which is related to the up-regulation of DNMT3a and DNMT3b proteins in erythroid leukemic HEL cells.
文摘BACKGROUND Accumulating evidence demonstrates that autoimmune hematopoietic failure and myeloid neoplasms have an intrinsic relationship with regard to clonal hematopoiesis and disease evolution.In approximately 10%-15%of patients with severe aplastic anemia(SAA),the disease phenotype is transformed into myeloid neoplasms following antithymocyte globulin plus cyclosporine-based immunosuppressive therapy.In some of these patients,myeloid neoplasms appear during or shortly after immunosuppressive therapy.Leukemic transformation in SAA patients during anti-tuberculosis treatment has not been reported.CASE SUMMARY A middle-aged Chinese female had a 6-year history of non-SAA and a 2-year history of paroxysmal nocturnal hemoglobinuria(PNH).With aggravation of systemic inflammatory symptoms,severe pancytopenia developed,and her hemoglobinuria disappeared.Laboratory findings in cytological,immunological and cytogenetic analyses of bone marrow samples met the diagnostic criteria for“SAA.”Definitive diagnosis of disseminated tuberculosis was made in the search for infectious niches.Remarkable improvement in hematological parameters was achieved within 1 mo of anti-tuberculosis treatment,and complete hematological remission was achieved within 4 mo of treatment.Frustratingly,the hematological response lasted for only 3 mo,and pancytopenia reemerged.At this time,cytological findings(increased bone marrow cellularity and an increased percentage of myeloblasts that accounted for 16.0%of all nucleated hematopoietic cells),immunological findings(increased percentage of cluster of differentiation 34+cells that accounted for 12.28%of all nucleated hematopoietic cells)and molecular biological findings(identification of somatic mutations in nucleophosmin-1 and casitas B-lineage lymphoma genes)revealed that“SAA”had transformed into acute myeloid leukemia with mutated nucleophosmin-1.The transformation process suggested that the leukemic clones were preexistent but were suppressed in the PNH and SAA stages,as development of sy
