Objective To elucidate the interaction between osteoblast of bone marrow microenvironment and leukemia cells,and to investigate the role of osteoblast in the leukemia cells survival and apoptosis and the influence of leukemia cells on the osteoblast.Methods Leukemia cells from AML1-ETO9a-Rac1 mouse leukemia model and osteoblast cells were used.The ratio of GFP+ leukemia cells that co-cultured with or without osteoblast was detected by FACS.In addition,the apoptosis level of leukemia cells was detected by flow cytometry by PI and Annexin Ⅴ labeling.Activation level of PARP was determined by Western-blot.Real-time PCR (RT-PCR) was utilized to detect the mRNA level of TPO,N-cadherin,OPN and Ang1 in osteoblast which was separated from leukemic mice.Results The ratio of GFP+ cells in AE9a-Rac1 leukemia cells co-cultured with osteoblast cell was significantly higher than that of AE9a-Rac1 leukemia cells cultured alone.The apoptotic level of AE9a-Rac 1 leukemia cells cultured alone was significant higher than that of AE9a-Rac 1 leukemia cells in co-culture system.Western blot showed that activated level of PARP in AE9a-Rac1 leukemia cells co-cultured with osteoblast was lower than that cultured alone.RT-PCR result showed that TPO and N-cadherin mRNA levels in primary osteoblast separated from leukemic mice were higher than that from normal mice.Ang1 and OPN mRNA levels of osteoblast from leukemia mice were lower.Conclusion Osteoblast cell can support the survival and inhibit the apoptosis of leukemia cells.Leukemia cells can influence the functions of osteoblast by microenvironment associated cytokines production.

Objective To detect the proteins levels of RhoA and CDC42 in bone marrow mononucleated cells (BMMC) of patients with primary acute leukemia,and further determine the role of abnormal interactions between hematopoietic progenitor and bone marrow microenvironment on abnormal behaviors of leukemia cells. Methods BMMC samples were separated from 54 primary acute leukemia patients and 22 normal donors and the cell lysis samples were prepared. RhoA and CDC42 proteins were determined by Western blotting. Independent pair T test was conducted to evaluate whether the differences in RhoA and CDC42 expression were statistically significant between leukemia patients and normal donors. Spearman was applied in analyzing the correlation between expression of RhoA and CDC42 proteins and clinical characters of patients. Results RhoA and CDC42 proteins level of primary acute leukemia patients was significantly higher than that of normal samples. Especially, patients with M2,M3 and M5 subtypes exhibited significant higher RhoA proteins levels and M3 subtype exhibited significant higher CDC42 protein levels. Conclusion RhoA and CDC42 protein levels of primary acute leukemia patients are significantly higher than that of normal donors. This result suggests that RhoA and CDC42 associated efficient migration of leukemia cells could be implicated in abnormal interaction of leukemic cell with bone marrow microenvironment.

Objective of this study was to detect the expression of HtrA2 and WT1 mRNA in acute myeloid leukemia (AML) and investigate the relationship of their expression levels with clinical variates and correlation between them. The expression levels of HtrA2 and WT1 were measured by RQ-PCR in bone marrow cells in 104 newly diagnosed AML patients and leukemia cell lines (K562, HL-60, NB4, Kasumi-1, U937), and the relationship between expression level and clinical parameters (age, sex, WBC count, diagnosis and prognosis) was investigated. The results showed that (1) the expression of HtrA2 gene in newly diagnosed AML was lower than that of the normal controls (P < 0.01), while expression of WT1 gene in newly diagnosed AML was higher than that of the normal controls (P < 0.01), the expression levels of HtrA2 and WT1 genes both did not correlate with age, sex and WBC counts of patients. There were no significant difference of HtrA2 gene expression between different NCCN prognosis group, while WT1 gene expression in better-risk group was significantly lower than that in intermediate-risk group (P = 0.003). The HtrA2 expression level rose after treatment in both CR group and non-CR group (P < 0.05), while WT1 expression level significantly decreased after treatment only in CR group (P < 0.01). Negative correlation between HtrA2 and WT1 expression was also observed (r = -0.249, P = 0.011). It is concluded that the low expression of HtrA2 and high expression of WT1 are closely related with occurrence and development of acute leukemia, so up-regulating expression of HtrA2 and interfering expression of WT1 may become the targets for leukemia therapy in the future.
Adolescent ; Adult ; Aged ; Cell Line, Tumor ; Female ; High-Temperature Requirement A Serine Peptidase 2 ; Humans ; Leukemia, Myeloid, Acute ; genetics ; metabolism ; Male ; Middle Aged ; Mitochondrial Proteins ; genetics ; metabolism ; Serine Endopeptidases ; genetics ; metabolism ; WT1 Proteins ; genetics ; metabolism ; Young Adult

OBJECTIVETo explore the signal transduction pathway in the differentiation and apoptosis of leukemia cells induced by heat shock protein 90 (HSP90) inhibitor 17-Allyl amide-17-demethoxygeldanamycin (17AAG).

METHODSKasumi-1 cells were treated with increasing concentrations or exposure time of 17AAG. The total kit protein (CD117), phosphorylated kit protein and its downstream signaling molecules were measured by Western blot analysis. Mutated kit protein from control and 17AAG-treated Kasumi-1 cells was immunoprecipitated and immunoblotted for associated chaperones.

RESULTSTotal kit protein and kit activity were decreased in 17AAG treated cells, but c-kit mRNA level was not. Total AKT protein and phospho-AKT, as well as phospho-STAT3 were rapidly down-regulated in Kasumi-1 cell after treatment with 17AAG. There was no change in total STAT3 protein. Immunoprecipitation showed that 1 microM 17AAG treatment for 1 hour caused kit associated HSP90 decrease and HSP70 increase.

CONCLUSION17AAG-induced apoptosis of Kasumi-1 cells is associated with a decline in Asn822Lys mutated kit protein level and phosphorylated kit, and with a downregulation in its downstream activated signaling molecules involved in proliferation. AKT is a client protein of HSP90. The changes of kit associated HSP90 and HSP70 satisfy the circulation mode of molecular chaperone complex.

Apoptosis ; drug effects ; Benzoquinones ; pharmacology ; Cell Differentiation ; drug effects ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; Heat-Shock Proteins ; metabolism ; Humans ; Lactams, Macrocyclic ; pharmacology ; Leukemia ; metabolism ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-kit ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tumor Cells, Cultured

OBJECTIVETo explore the effect of 17-allylamide-17-demethoxygeldanamycin (17AAG), a heat shock protein 90 (HSP90) inhibitor, on the growth, differentiation and apoptosis of leukemic Kasumi-1 cells.

METHODSKasumi-1 cells were treated with 17AAG at different concentrations in suspension culture. Cell proliferation was analysed by MTT assay, expression of myeloid-specific differentiation antigen and cell cycle by flow cytometry, cell apoptosis by annexin V staining, agarose gel electrophoresis and flow cytometry. KIT protein was analysed by Western blot and c-kit mRNA by RT-PCR.

RESULTS17AAG treatment caused a dose-dependent inhibition of the cell proliferation with the IC(50) of 0.62 micromol/L. A dose-dependent increase in early apoptosis occurred at 24 hours treatment and in late apoptosis at 48 hours treatment. 17AAG induced a time- and dose-dependent increase in expression of myeloid cell surface protein CD11b and CD15, a progressive decline in S-phase cell fraction and an increase in G(0)/G(1) cells. When Kasumi-1 cells were incubated with 1 micromol/L of 17AAG, KIT protein began to decrease at 2 hours and KIT protein could hardly be detected at 20 hours, but c-kit mRNA was not decreased.

CONCLUSION17AAG treatment of Kasumi-1 cells could lower KIT protein expression, inhibit cell proliferation, induce cell partial differentiation, apoptosis and accumulation in G(0)/G(1) phase.

Apoptosis ; drug effects ; Benzoquinones ; pharmacology ; Cell Cycle ; drug effects ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; Humans ; Lactams, Macrocyclic ; pharmacology ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; RNA, Messenger ; genetics

This study was aimed to investigate the expression of c-MPL in acute myeloid leukemia (AML) and the correlation of the c-MPL expression with CD34 and CD38, so as to define the expression of c-MPL in leukemic stem cells. The expression levels of CD34, CD38 and c-MPL were detected by flow cytometry in bone marrow cells from 29 newly diagnosed AML patients. The relationship of c-MPL positive cell ratio with clinical parameters and correlation of c-MPL with CD34 and CD38 expression in AML patients were analyzed. The results showed that expression level of c-MPL in AML patients was significantly higher than that of normal controls (P < 0.05), and the expression level of c-MPL did not correlate with age, sex, white blood cell count, AML1-ETO fusion gene and remission after chemotherapy, but the expression of c-MPL in M2 and M5 patients was higher than that of normal control (P < 0.05). Expression of c-MPL in CD34 positive AML patients was obviously higher than that in CD34 negative AML patients (P < 0.01). c-MPL was significantly higher expressed in CD34(+) cells than that in CD34(-) cells (P < 0.001), while c-MPL expression was not significantly different between CD34(+)CD38(-) and CD34(+)CD38(-) cell groups. Positive correlation between c-MPL and CD34 expression was observed (r = 0.380, P = 0.042). It is concluded that expression of c-MPL is higher in AML patients, and positively correlates with the expression level of CD34. The c-MPL expresses in leukemic stem cells.
Adolescent ; Adult ; Aged ; Case-Control Studies ; Child ; Female ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Male ; Middle Aged ; Neoplastic Stem Cells ; metabolism ; Receptors, Thrombopoietin ; metabolism ; Young Adult

This study was aimed to explore the role and mechanism of AML1a in abnormal hematopoiesis in mice. Plasmids pMSCV-FLAG-AML1a-IRES-YFP and pMSCV-IRES-YFP together with envelope-encoding plasmid pECO and packaging plasmid pGP were respectively transfected into 293T cells by using a method of calcium phosphate precipitation to produce retrovirus. Bone marrow mononuclear cells (BMMNC) from male C57BL/6J mice were transfected with the retroviral vector MSCV expressing FLAG-AML1a fusion protein and yellow fluorescent protein (YFP). The cells were cultured in M3434 semi-solid medium for colony formation assay and in M5300 fluid medium containing murine IL-3 (mIL-3), IL-6 (mIL-6) and SCF (mSCF) for long-term culture. The results showed that transfection of AML1a into BMMNC enhanced colony formation, colony size of the AML1a group was significantly larger than that of the control group, and the colonies were mainly composed of CFU-E and CFU-GEMM. In the long-term culture, AML1a-transfected BMMNC showed differentiation block, while the control cells were in a more mature stage. It is concluded that AML1a may block the normal hematopoiesis at the stage of primitive progenitors. At the same time, AML1a also enhances the proliferation activity of primitive progenitor cells.
Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; Cell Proliferation ; Colony-Forming Units Assay ; Core Binding Factor Alpha 2 Subunit ; genetics ; Genetic Vectors ; Hematopoietic Stem Cells ; cytology ; Male ; Mice ; Mice, Inbred C57BL ; Retroviridae ; genetics ; Transfection

iASPP can prompt the cell proliferation and inhibit the apoptosis of many cells. There are putative binding sites of transcription factor GATA-2 upstream of iASPP transcription start site. GATA-2 plays an important role in the proliferation and differentiation of hematopoietic stem cells (HSC) and progenitors. This study was aimed to explore the role of GATA-2 protein in iASPP gene transcription. Firstly, the expression of iASPP and GATA-2 protein in some leukemia cell lines was detected by Western blot. Second, The expressive vector of pCMV5-GATA2 and the luciferase reporter vectors containing possible binding sites of GATA-2 were constructed and co-transfected into HEK293 and CV-1 cells. Then the luciferase activity was assayed by luminometer. Also, ChIP assays were performed to further confirm the specific binding of GATA-2 to iASPP promoter. The results showed that GATA-2 was overexpressed in most cell lines with high level of iASPP. GATA-2 exhibited a significant effect on luciferase activity of reporter gene iASPP and in a dose-dependant manner. The relative luciferase activity was up-regulated to about two-fold of the empty vector control when the transfection dose of pCMV5-GATA2 plasmid was increased to 100 ng. While the effect was more significant in CV-1 cells and showed a 6.7-fold increase. The ChIP assay demonstrated the in vivo specific binding of GATA-2 to iASPP. The binding sites of GATA2 were located between nt -361 ∼ -334 in upstream of iASPP gene transcription start site. It is concluded that transcription factor GATA-2 can bind with the cis-regulatory region of the iASPP promoter and up-regulate iASPP expression.
Animals ; Cell Line ; Cercopithecus aethiops ; GATA2 Transcription Factor ; genetics ; Gene Expression Regulation, Leukemic ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; K562 Cells ; Repressor Proteins ; genetics ; Transcription, Genetic ; Transcriptional Activation ; Transfection

This study was purposed to explore the expression of Ang-1, Ang-2, Tie-2, Kindlin-2, Kindlin-3 in different leukemia cell lines and bone marrow of acute myeloid leukemia (AML) patients and its clinical significance. The levels of Ang-1, Ang-2, Tie-2, Kindlin-2, Kindlin-3 in bone marrow of AML patients and nontumorous control group as well as leukemia cell lines (K562, KG-1a, U937, HL-60 and Jurkat) were detected by RQ-PCR. The difference of positive rate and expression level between AML patients and controls was analyzed. The relation between 5 genes and their relationship with typing and prognosis of AML were investigated. The results showed that Ang-1, Ang-2, Kindlin-3 expressed in K562, KG-1a, U937, HL-60 and Jurkat cells. Tie-2 only expressed in KG-1a and HL-60 cells. Kindlin-2 expressed in K562, KG-1a and HL-60 cells. All of these 5 genes expressed in AML patients and nontumorous controls. The expression level of Ang-1 and Ang-2 in patients with higher WBC count (≥ 30 × 10(9)/L) was significantly higher than that in patients with lower WBC (< 30 × 10(9)/L, P < 0.001, P < 0.001). The expression level of Ang-1 and Ang-2 in patients with t(8;21) or t(15;17) was significantly lower (P < 0.001, P = 0.005). In the NCCN better-risk group, Ang-1 expressed lower (P = 0.020). The group with lower expression of Ang-1 showed a higher complete remission (CR) rate (P = 0.027). The expression level of Kindlin-2 was lower in AML patients (P = 0.010), lower in patients with higher WBC (≥ 30 × 10(9)/L, P = 0.020), and higher in patients with t(8;21) or t(15;17). The expression levels of both Kindlin-2 and Kindlin-3 were significantly higher after CR (P < 0.001, P = 0.004). It is concluded that Ang-1 closely correlated with the poor prognosis of AML. Kindlin-2 lowly expresses in AML, which has a close relation with the favorable prognosis of AML. Kindlin-2 can be a marker for favorable prognosis of AML.
Adolescent ; Adult ; Aged ; Angiopoietins ; metabolism ; Case-Control Studies ; Cell Line, Tumor ; Female ; Humans ; Leukemia, Myeloid, Acute ; diagnosis ; metabolism ; Male ; Membrane Proteins ; metabolism ; Middle Aged ; Neoplasm Proteins ; metabolism ; Prognosis ; Young Adult

OBJECTIVETo investigate the expression of cell surface E-cadherin in leukemia cell and the correlation of cell membrane localization of beta-catenin with E-cadherin expression.

METHODSBone marrow samples from 46 patients with acute leukemia and 17 normal donors were analyzed. Cell surface expression of E-cadherin and membrane localization of beta-catenin were labeled by immunofluorescence and analyzed with a laser scanning confocal fluorescence microscope in 14 specimens.

RESULTSCell surface E-cadherin expression level was significantly lower in leukemia cells (with the median fluorescent intensity of 16.78) than in normal hematopoietic progenitors (26.03). Correlation analysis showed that cell membrane localization of beta-catenin was correlated with E-cadherin expression (r = 0.74, P = 0.002). After E-cadherin was induced to express in leukemic cell by 5-Aza-CdR, membranous expression of beta-catenin was elevated while the nuclear expression reduced, indicating that E-cadherin-mediated adhesions could recruit beta-catenin to cell membrane.

CONCLUSIONThe loss of E-cadherin in leukemia cells may result in beta-catenin translocating to the nuclear and transcriptional activation of its target genes.

Cadherins ; metabolism ; Case-Control Studies ; Cell Membrane ; metabolism ; Humans ; Leukemia ; metabolism ; pathology ; beta Catenin ; metabolism