OBJECTIVETo 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.

METHODSThe 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.

RESULTSThe 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) 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.

CONCLUSIONSBufalin can not only significantly inhibit the proliferation of HEL cells and arrest cell cycle at G/Gphase, 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.

Apoptosis ; drug effects ; genetics ; Bufanolides ; pharmacology ; Cell Cycle Checkpoints ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Shape ; drug effects ; DNA (Cytosine-5-)-Methyltransferases ; metabolism ; DNA Methylation ; drug effects ; genetics ; Gene Expression Regulation, Leukemic ; drug effects ; Humans ; Leukemia, Erythroblastic, Acute ; enzymology ; genetics ; pathology ; RNA, Messenger ; genetics ; metabolism ; Up-Regulation ; drug effects ; genetics ; WT1 Proteins ; genetics ; metabolism

OBJECTIVETo explore the effects of Danshen Injection () on inhibition proliferation, inducing apoptosis and its possible mechanisms on human erythroid leukemic (HEL) cells.

METHODSThe 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 (MTT) 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.

RESULTSThe 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.

CONCLUSIONDanshen 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.

Apoptosis ; drug effects ; Base Sequence ; Cell Proliferation ; drug effects ; DNA Primers ; Down-Regulation ; drug effects ; Humans ; Janus Kinase 2 ; genetics ; metabolism ; Leukemia, Erythroblastic, Acute ; enzymology ; metabolism ; pathology ; Mutation ; Phosphorylation ; Plant Extracts ; pharmacology ; Polymerase Chain Reaction ; Salvia miltiorrhiza ; chemistry

The activity of the mTOR pathway is frequently increased in acute myeloid leukemia, and is tightly related with cellular proliferation. Leucine is tightly linked to the mTOR pathway and can activate it, thereby stimulating cellular proliferation. LAT3 is a major transporter for leucine, and suppression of its expression can reduce cell proliferation. Here, we show that suppression of LAT3 expression can reduce proliferation of the acute leukemia cell line, K562. We investigated the mRNA and protein expression of LAT3 in several leukemia cell lines and normal peripheral blood mononuclear cells (PBMNCs) using RT-PCR and Western blotting. We also evaluated cell viability using a methyl thiazolyl tetrazolium (MTT) assay after blocking LAT3 expression with either shRNA targeted to LAT3 or a small molecular inhibitor BCH (2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid). LAT3 mRNA and protein expression was detected in leukemia cell lines, but not in normal PBMNCs. Using K562 cells, it was found that cellular proliferation and mTOR pathway activity were significantly reduced when LAT3 was blocked with either shRNA or BCH. Our results suggest that leukemia cell proliferation can be significantly suppressed by blocking LAT3. This finding may lead to a new strategy to develop clinical therapy for the treatment of acute myeloid leukemia.
Amino Acid Transport Systems, Basic ; antagonists & inhibitors ; genetics ; metabolism ; Amino Acids, Cyclic ; pharmacology ; Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; Cell Survival ; drug effects ; genetics ; Cells, Cultured ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Leukemic ; genetics ; HL-60 Cells ; Humans ; Jurkat Cells ; K562 Cells ; Leukemia, Erythroblastic, Acute ; genetics ; metabolism ; pathology ; Phosphorylation ; drug effects ; RNA Interference ; Reverse Transcriptase Polymerase Chain Reaction ; TOR Serine-Threonine Kinases ; metabolism

The molecular pathogenesis of leukemia is poorly understood. Earlier studies have shown both Wilms' tumor 1 suppressor gene (WT1) and CML28 abnormally expressed in malignant diseases of the hematopoietic system and WT1 played an important role in leukemogenesis. However, the relationship between molecular CML28 and WT1 has not been reported. Here we described the use of small interfering RNA (siRNA) against WT1 and CML28 in leukemic cell line K562 to examine the interaction between CML28 and WT1. WT1 and CML28 gene expression in transfected K562 cells was detected by using RQ-PCR and Western blotting. K562 cells transfected with WT1-siRNA could greatly decrease both mRNA and protein expression levels of WT1 and CML28. In contrast, CML28-siRNA did not exert effect on WT1. Further, subcellular co-localization assay showed that the two proteins could co-localize in the cytoplasm of K562 cells, but WT1/CML28 complexes were not detected by using immunoprecipitation. It was suggested that there exists the relationship between CML28 and WT1. CML28 may be a downstream target molecule of WT1 and regulated by WT1, which will provide important clues for further study on the role of CML28 and WT1 in leukemic cells.
Antigens, Neoplasm ; metabolism ; Cell Line, Tumor ; Exosome Multienzyme Ribonuclease Complex ; metabolism ; Humans ; K562 Cells ; Leukemia, Erythroblastic, Acute ; metabolism ; Neoplasm Proteins ; metabolism ; Protein Interaction Mapping ; RNA-Binding Proteins ; metabolism ; Subcellular Fractions ; metabolism ; WT1 Proteins ; metabolism

OBJECTIVETo explore the role of aquaporin-1 (AQP1) gene in erythroid differentiation of erythroleukemia K562 cells induced by retinoic acid (RA).

METHODSK562 cells were cultured in the presence of 1 µmol/L RA for varying lengths of time, and γ-globin mRNA expression and hemoglobin content in the cells were detected by real-time PCR (RT-PCR) and ultraviolet spectrophotometry, respectively, to evaluate the erythroid differentiation of K562 cells. RT-PCR and Western blotting were used to examine AQP1 expression in the cells following RA treatment. A retroviral expression vector of AQP1 small interfering RNA (pSUPER-retro-puro-shAQP1) was constructed and transfected into K562 cells to establish a K562 cell line with stable AQP1 down-regulation (K562-shAQP1), in which the changes in γ-globin and hemoglobin expressions after RA treatment were detected.

RESULTSRA treatment significantly increased γ-globin and hemoglobin expressions in K562 cells (P<0.01), causing also significantly enhanced AQP1 mRNA and protein expressions over time (P<0.01). Transfection with the recombinant plasmids pSuper-retro-puro-shAQP1 resulted in stable AQP1 suppression in K562 cells (P<0.01), which showed markedly reduced γ-globin and hemoglobin expressions after RA induction as compared to the control K562 cells (P<0.01).

CONCLUSIONK562 cells show a significant increase of AQP1 expression after RA-induced erythroid differentiation, and suppression of AQP1 expression can partially block the effect of RA, suggesting the important role of AQP1 in RA-induced erythroid differentiation of K562 cells.

Aquaporin 1 ; antagonists & inhibitors ; metabolism ; Cell Differentiation ; drug effects ; Humans ; K562 Cells ; Leukemia, Erythroblastic, Acute ; metabolism ; RNA, Messenger ; genetics ; RNA, Small Interfering ; genetics ; Tretinoin ; pharmacology

This study was aimed to investigate the inhibitory effect of emodin on the proliferation of HEL cells, the inducing apoptosis effect of HEL cells and their mechanisms. The proliferation inhibition was detected by MTT method; the change of morphology was observed by AO/EB stains; the cell cycle and apoptosis was analyzed by flow cytometry; the expressions of Akt, P-Akt, P-GSK3β and HSP70 proteins were determined by Western blot. The results indicated that emodin displayed significant anti-proliferative effect on HEL cells in a dose dependent manner(r = 0.99), with IC(50) value of 4.19 µmol/L; AO/EB stains showed that the morphology of HEL cells obviously changed after emodin treatment for 24 hours, and at 24 and 48 hours the apoptosis rates of HEL cells treated by emodin were (27.35 ± 1.68)% and (58.49 ± 1.55)% respectively. Compared with blank control group, the cell ratio in G(0)/G(1) phase increased while that in S phase decreased (p < 0.01); the expression of Akt protein was not changed (p > 0.05), and that of P-Akt, P-GSK3β and HSP70 proteins were down-regulated (p < 0.05). It is concluded that emodin efficiently inhibits the HEL cell proliferation and induces apoptosis of HEL cells, which may be related to the down-regulation of P-Akt, P-GSK3β and HSP70 proteins expression.
Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Emodin ; pharmacology ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; HSP70 Heat-Shock Proteins ; metabolism ; Humans ; Leukemia, Erythroblastic, Acute ; metabolism ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism

OBJECTIVETo explore the mechanism of matrine (Mat) induced human erythroleukemia TF-1 cell apoptosis and its effect on SALL4 expression.

METHODDifferent concentrations of the Mat (0.5, 1.0, 1.5, 2.0 g x L(-1) ) were cultured in vitro in TF-1 cells at different time (24, 48, 72 h). Cell proliferation was assayed by MTT. Cell cycle was determined by flow cytometry (FCM). Cell apoptosis was detected by Annexin V and PI double staining method. SALL4 mRNA expression was detected by reverse transcription RT-PCR (RTT-PCR).

RESULTAdministrated with Mat (0.5-2.0 g x L(-1)) after 24, 48, 72 h, the proliferation of TF-1 cells were inhibited (P < 0.01) , and in dose- and time-dependent manner. Half inhibitory concentration (IC50 ) was 1.0 g L(-1) at 48 h. After 48 h that the Mat acted on TF-1 cells, the proportion of G0/G1 phase cells increased while compared with the control group, and S phase cells decreased (P < 0.01). Apoptosis were 8.6% , 11.21%, 15.26% , 17.63%, which showed statistically significant difference (P < 0.01) compared with the control group (5.05%). RT-PCR results showed the ratio between SALL4 mRNA expression and beta-actin (internal reference) expression significantly decreased (P < 0.01) with Mat dose increased.

CONCLUSIONIn a certain range of concentration and time, Mat can inhibit TFT-1 cells proliferation. The mechanism is to make the cells G0/G1 phase blocked, to inhibit SALL4 gene expression and induce cell apoptosis.

Alkaloids ; pharmacology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Gene Expression ; drug effects ; Humans ; Leukemia, Erythroblastic, Acute ; drug therapy ; genetics ; metabolism ; physiopathology ; Quinolizines ; pharmacology ; Transcription Factors ; genetics ; metabolism

OBJECTIVETo observe matrine-induced erythroid differentiation of K562 cells in relation to activation of the apoptotic pathway in vitro.

METHODSK562 cells were cultured in the presence or absence of matrine at different concentrations for 4 days, and the morphological and ultramicrostructural changes of the cells were observed using inverted microscopy and transmission electron microscopy, respectively. The expression of apoptosis-related protein p27kip1 was detected by immunocytochemistry.

RESULTSCompared to untreated K562 cells, the cells treated with matrine at 0.10 g/L exhibited apoptostic characteristics in the cellular morphology and ultramicrostructure, with the expression of p27kip1 protein upregulated in a concentration- and time-dependent manner.

CONCLUSIONMatrine-induced erythroid differentiation of K562 cells is associated with cell apoptosis, and upregulation of p27kip1 protein expression may play a crucial role in the process of apoptosis.

Alkaloids ; pharmacology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; physiology ; Cyclin-Dependent Kinase Inhibitor p27 ; biosynthesis ; Dose-Response Relationship, Drug ; Humans ; Immunohistochemistry ; K562 Cells ; Leukemia, Erythroblastic, Acute ; metabolism ; pathology ; Microscopy, Electron, Transmission ; Quinolizines ; pharmacology ; Signal Transduction ; drug effects ; Time Factors

The objective of this study was to investigate the biological characteristics and the therapeutic effect in patients with acute erythroleukemia (AML-M(6)). Morphology, immunophenotype and cytogenetics were retrospectively analyzed in 29 patients with AML-M(6) and were compared with 30 AML-M(2) patients. The results showed that there were immature cells (2% - 10%) and erythroblast, and puncture of bone marrow revealed myelodysplastic features involving multiple hemopoietic lineages in bone marrow of 19 patients. Flow cytometry indicated that the expression frequency of Gly-A in M(6) significantly increased (66.67 +/- 23.86)% and higher than that in M(1), M(2), M(3), M(4) and M(5) (P < 0.01). The expression frequencies of HLA-DR (60.00 +/- 24.79%), CD34 (40.00 +/- 24.79%), CD38 (33.33 +/- 23.86%) in M(6) were high, and the frequencies of myeloid immunophenotypes CD13 (66.67 +/- 23.86%), MPO (33.33 +/- 23.86%), CD33 (46.67 +/- 25.25%), CD15 (33.33 +/- 23.86%), CD117 (46.67 +/- 25.25%) were common as well in M(6). Lymphocytic immunophenotypes CD3, CD4, CD19 were detected in part of patients with M(6), and the expression frequencies of CD4 was 26.67%. The expression frequences of CD38, CD33, CD15, MPO in M(6) were less common than that in M(2) (P < 0.01). In 4 out of 9 M(6) patients the chromosomal abnormatility (44.44%) was seen, in one of which complex chromosome abnormality was found. The complete remmision rate of M(6) patients was 29.41%, and lower than that of M(2) patients (68.18%, P < 0.01). It is concluded that Gly-A is a specific immunophenotype in M(6), which can help to distinguish M(6) from other types of acute myeloid leukemia. Poor clinical therapeutic response may correlated with its biological characteristics.
Adolescent ; Adult ; Antigens, CD ; immunology ; metabolism ; Child ; Chromosome Aberrations ; Female ; Humans ; Immunophenotyping ; Karyotyping ; Leukemia, Erythroblastic, Acute ; immunology ; metabolism ; Male ; Membrane Glycoproteins ; immunology ; metabolism ; Middle Aged ; Retrospective Studies ; Young Adult

OBJECTIVETo investigate the effects of curcumin (Cur) and erythromycin (EM) on multidrug resistance (MDR) reversal of K562/A02 cell line and their mechanism.

METHODSMTT assay was employed to determine the sensitivity of Cur, EM-treated K562/A02 cells to adriamycin (ADM). Flow cytometry was used to measure intracellular mean fluorescence intensity (MFI) of daunorubicin (DNR). P-gp expression was determined by immunohistochemistry. RT-PCR technique was used to examine the mdr1 mRNA level.

RESULTSIC(50) of ADM in K562/A02 cells was decreased when treated with Cur or EM, and the reversal times (RvT) was 4.9, 3.7 respectively. The RvT reached to 11.3 when treated with Cur (2.5 microg/ml) combined with EM (120 microg/ml). The DNR MFI in K562/A02 cells was significantly lower than that in K562 cells (P < 0.01), and was increased significantly when treated with Cur (2.5 microg/ml) or EM (120 microg/ml) (P < 0.05). There was no significant difference between DNR MFI of K562/A02 cells treated with Cur (2.5 microg/ml) or EM (120 microg/ml). Immunohistochemistry showed that P-gp expression was significantly higher in K562/A02 cells than in K562 cells (P < 0.01), and was reduced in K562/A02 cells treated with each (P < 0.01), though being still higher than that in K562 cells (P < 0.01). P-gp expression of K562/A02 cells treated with each drug for 5 days were lower than that for 3 days (P < 0.01), and lowered further when treated with Cur and EM together (P < 0.01). Mdr1 mRNA level in K562/A02 cells was higher than in K562 cells (P < 0.01), and was decreased when treated with each of the drugs (P < 0.01). The mdr1 mRNA level of K562/A02 cells treated with Cur (2.5 microg/ml) plus EM (120 microg/ml) was decreased most significantly than that treated with other group of drugs. After 5 day treatment the mdr1 mRNA level of K562/A02 cells with Cur (2.5 microg/ml) was lower than that with EM 120 microg/ml (P < 0.01).

CONCLUSIONSEither Cur or EM can partly reverse the multidrug resistance of K562/A02 cells and decrease the expression and function of P-gp in a time-dependent way. MDR reversing effect of Cur combined with EM is stronger than that of Cur or EM alone.

ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Antineoplastic Agents ; pharmacology ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Curcumin ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drug Synergism ; Epirubicin ; pharmacology ; Erythromycin ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; Immunohistochemistry ; K562 Cells ; Leukemia, Erythroblastic, Acute ; genetics ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors