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

OBJECTIVETo investigate the effect of total flavonoids of Hedysarum polybotry on the proliferation, cell cycle, and expressions of p21(Ras) and proliferating cell nuclear antigen (PCNA) gene in erythroleukemia cell line K562.

METHODSThe effect of total flavonoids of Hedysarum polybotry on K562 cell line survival was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction assay. The time- and dose-dependent manner was also observed. The cell cycle and apoptosis were analyzed with flow cytometry (FCM). The immunocytochemistry method was applied to quantitatively analyze the effects of flavonoids of Hedysarum polybotry on changes p21(Ras) and PCNA gene expressions.

RESULTSFlavonoids of Hedysarum polybotry (20-100 μg/mL) significantly inhibited the proliferation of K562 cells in a time- and dose-dependent manner. After K562 cells were cultured for 48 h, total flavonoids of Hedysarum polybotry had no significant effect on the apoptosis of K562 cells but showed significantly inhibition (P<0.01), indicating that total flavonoids of Hedysarum polybotry could induce K562 cells arrested at G(0)/G(1) and G(2)/M phases. Compared with the control group, p21(Ras) and PCNA gene expressions were decreased significantly in K562 cells treated with total flavonoids of Hedysarum polybotry (40 and 80 μg/mL, respectively) for 48 h.

CONCLUSIONThe inhibitory effect on proliferation of K562 cells was observed in the groups treated with flavonoids of Hedysarum polybotry, which might be related to cells arresting.

Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Flavonoids ; pharmacology ; Gene Expression Regulation, Leukemic ; drug effects ; Humans ; K562 Cells ; Leukemia, Erythroblastic, Acute ; drug therapy ; genetics ; pathology ; Oncogene Protein p21(ras) ; genetics ; Proliferating Cell Nuclear Antigen ; genetics ; Ranunculaceae ; chemistry

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

AML relapsing as ALL has rarely been reported. We describe the case of a 62-yr-old man who was diagnosed with erythroleukemia with a complex karyotype and achieved complete hematologic and cytogenetic remission after induction chemotherapy. However, 4 months after the initial diagnosis, he showed relapse with blasts showing a different morphology and immunophenotype and was diagnosed with precursor B-cell ALL. The relapsing precursor B-cell ALL presented with the same leukemic clones as the primary erythroleukemia. Cytogenetic analysis of his bone marrow (BM) at the time of the primary erythroleukemia showed complex karyotypic abnormalities, including monosomy 5 and monosomy 7. At relapse, his BM showed reemergence of these leukemic clones of complex karyotypic abnormalities with clonal switch. To our knowledge, this is the first case of a lineage switch from erythroleukemia to ALL.
Acute Disease ; Antimetabolites, Antineoplastic/therapeutic use ; Bone Marrow Cells/pathology ; Cell Lineage ; Cell Transformation, Neoplastic ; Chromosome Deletion ; Chromosomes, Human, Pair 5 ; Chromosomes, Human, Pair 7 ; Cytarabine/therapeutic use ; Drug Therapy, Combination ; Humans ; Immunophenotyping ; Karyotyping ; Leukemia, Erythroblastic, Acute/*diagnosis/drug therapy ; Male ; Middle Aged ; Monosomy ; Naphthacenes/therapeutic use ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/*diagnosis/pathology ; Recurrence

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

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

To investigate the relationship between nm23-H1 gene and human chronic myeloblastic leukemia we designed siRNAs which target nm23-H1 gene. According to the principles of designing siRNA, we selected three siRNAs and transfected them into K562 cells by lipofectamine2000. The expression levels of nm23-H1 mRNA were detected by reverse transcriptase polymerase chain reaction after transfection for 24 hours. The expression levels of nm23-H1 protein were assayed by immunocytochemical method after transfection for 48 hours. And after transfection for 24, 48 and 72 hours, cell proliferation was determined by MTT method. Among the three siRNAs, siNM526 can effectively inhibit the expression of nm23-H1 on mRNA and protein levels. The growth of K562 cells was suppressed after transfection of siNM526. These results suggest that low expression level of nm23-H1 in K562 cells inhibited cell proliferation, namely reduced malignant degree of them. Therefore nm23-H1 gene might be a potential target of leukemia treatment.
Cell Proliferation ; Humans ; K562 Cells ; Leukemia, Erythroblastic, Acute ; genetics ; pathology ; NM23 Nucleoside Diphosphate Kinases ; biosynthesis ; genetics ; RNA Interference ; RNA, Messenger ; biosynthesis ; genetics ; RNA, Small Interfering ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

The changes in the cellular main components of the mouse erythroleukemia cell line MEL for TFAR19 gene transfection were studied by the technology of Fourier transform infrared spectroscopy (FTIR). Using the method of gene transfection with liposome, we obtained MEL-TF19 cell line, which stably carries TFAR19, a novel apoptosis-related gene. The expression of the gene on mRNA level was confirmed by RT-PCR. Then, FTIR spectra of the cells were measured in the course of apoptosis induced by serum deprivation. Our results indicated that after being transfected with TFAR19 gene, MEL-TF19 cells exhibited relatively higher protein content, higher transcriptional activity, and relatively lower phospholipid content as compared with those exhibited by MEL cells. All the above changes reflect the apoptosis-promoting effect of TFAR19 gene, and maybe account for the cellular rheological changes after TFAR19 gene transfection, which were discovered in our previous study.
Animals ; Apoptosis ; genetics ; Apoptosis Regulatory Proteins ; Cell Line, Tumor ; Genes, Tumor Suppressor ; Leukemia, Erythroblastic, Acute ; genetics ; pathology ; Mice ; Molecular Sequence Data ; Neoplasm Proteins ; genetics ; pharmacology ; Spectroscopy, Fourier Transform Infrared ; Transfection