OBJECTIVETo investigate the effect of SHIP gene mutation on the cell cycle and its related gene expression in K562 cells.

METHODSThe recombined green fluorescent protein (GFP) containing FIV-SHIP gene was transfected into K562 cells. The transfection efficiency and cell cycle of K562/SHIP were assessed by flow cytometry (FCM). The proliferation of K562 cells was detected by MTT assay, the mRNA levels of SHIP by real-time fluorescent relative-quantification reverse transcriptional PCR (FQ-PCR), and the protein levels of SHIP, Cyclin D1, p21(WAF1/CIPI) and p27(KIP1) by Western blot.

RESULTSWild type SHIP inhibited K562 cell proliferation and caused a G(0)/G(1) arrest \[(34.2 +/- 7.8)% vs (0.7 +/- 8.3)% (P < 0.01)\]; while the point mutation of SHIP gene did not show such effect. Western blot results showed that the Akt phosphorylation and cyclin D1 expression was significantly decreased (P < 0.01), and the expression of p27(KIP1) and p21(WAF1/CIPI) increased. Site-directed mutation of SHIP gene SH2 domain (TTC-->CTC, Phe-->Leu) did not influence the Akt phosphorylation and cyclins (P > 0.05).

CONCLUSION(1) wtSHIP gene can down-regulate Akt phosphorylation and result in inhibition of cyclin D1 expression, up-regulating p27(KIP1) and p21(WAF1/CIPI) expression, finally leading to the reduction of K562 cell proliferation, and inducing G(0)/G(1) phase arrest. (2) SHIP gene suppresses the proliferation of K562, being dependent on its intact structure and function.

Cell Cycle Proteins ; metabolism ; Humans ; Inositol Polyphosphate 5-Phosphatases ; K562 Cells ; Mutation ; Phosphoric Monoester Hydrolases ; genetics ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Transfection

OBJECTIVETo explore the effect of mutation in PxxP domain of SHIP on migration and invasion of leukemia cells and its mechanism.

METHODSThe lentiviral vector mediated wild type SHIP (wtSHIP) and mutant SHIP (muSHIP) plasmids were transfected into K562 cells through gene transfection techniques. Expression of SHIP at mRNA and protein level was detected by real-time PCR and Western blot, respectively. Transwell assay was used to analyze the difference between the migration and invasion ability of the K562/wtSHIP and the K562/muSHIP cells after transfection. Primary migration associated factor FAK, MMP and NF-κB were assayed by Western blot.

RESULTSAfter transfection, the SHIP expression in transfected K562 cells were significantly increased. Compared with the migration ability of K562/wtSHIP\[(15.8 ± 1.4)%\], that of K562/muSHIP cells \[(54.3 ± 2.4)% \] increased greatly and almost at the same level of that of K562/pFIV\[(50.3 ± 3.8)%\] (P < 0.01). The invasion assay also showed that K562/wtSHIP\[(32 ± 6)/HP\] has a lower invasion ability than that of the K562/muSHIP group \[(83 ± 16)/HP\] and K562/pFIV group \[(78 ± 13)/HP\] (P < 0.01). Western blot analysis showed that the expression of p-FAK and NF-κB was up-regulated in K562/muSHIP group compared to that of the K562/wtSHIP group.

CONCLUSIONSThe results confirmed that mutation in PxxP domain of SHIP gene played an important role in negative regulating function of SHIP gene. The mutation affects the cell migration and invasion ability through increase in MMP-9 expression, FAK phosphorylation and NF-κB activation. It suggested that the mutation of PxxP domain in SHIP gene might be pathogenic, and be one of the reasons for SHIP abnormality in leukemia.

Cell Movement ; Genetic Vectors ; Humans ; Inositol Polyphosphate 5-Phosphatases ; K562 Cells ; Leukemia ; pathology ; Mutation ; Phosphoric Monoester Hydrolases ; genetics ; Plasmids

The src homology 2 (SH2)-domain containing inositol-5-phosphatase (SHIP) is another recently identified lipid phosphatase after phosphatase and tensin homology deleted on chromosome ten gene (PTEN). It plays an important role in negatively regulating the proliferation of hematopoietic cells. The relationship between SHIP and the inhibition of tumor proliferation is rarely reported. The purpose of this study is to evaluate the apoptosis induced by SHIP gene in K562 cell line and to explore the involved signaling pathway. The K562 cells were transfected with human SHIP gene by using the lentiviral vector containing SHIP, and the transfection was verified by fluorescent quantitative PCR (FQ-PCR) and Western blot. Then the effects of SHIP protein expression on cell growth and apoptosis were measured. The levels of p-Akt, bcl-2 family, caspase and the activity of NFkappaB were assayed by Western blot and ELISA, respectively. The results are as follows: (1) Human leukemia cell line K562 was SHIP-negative; (2) Transfection with SHIP gene led to the re-expression of SHIP mRNA and protein in K562, as shown by FQ-PCR and Western blot; (3) The expression of SHIP protein inhibited cell growth and significantly increased apoptosis in K562 cells; (4) Compared to that in control group, the expression level of p-Akt-308 and p-Akt-473 in SHIP-expressing cell group decreased significantly (P<0.01); SHIP activated caspase-9, caspase-3, up-regulated protein levels of bad, p27, down-regulated expression of bcl-xL, while it had no effect on the expression of bcl-2 and bax. Furthermore, the inhibition of NF-kappaB was achieved along with the inactivation of Akt. These data suggest that SHIP gene has potential abilities to inhibit K562 leukemic cell proliferation and induce its apoptosis via inactivating PI3K/Akt pathway. The loss of SHIP might be the explanation of aberrant high-level p-Akt in human leukemia. It may be at least one of the mechanisms by which the loss of SHIP expression contributes to leukemia progression.
Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Cell Proliferation ; Down-Regulation ; Genetic Vectors ; Humans ; Inositol Polyphosphate 5-Phosphatases ; K562 Cells ; NF-kappa B ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphoric Monoester Hydrolases ; genetics ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; Transfection

OBJECTIVETo observe the expression of dynamin-1 and phosphor-dynamin-1 in the hippocampus of children and rats with mesial temporal lobe epilepsy (MTLE) and to investigate the roles of dynamin-1 and phosphor-dynamin-1 in the development of MTLE.

METHODSMale Sprague-Dawley rats (aged 25 days) were randomly divided into acute control (AC), acute seizure (AS), latent control (LC), latent seizure (LS), chronic control (CC) and chronic spontaneous seizure (CS) groups. Lithium chloride-pilocarpine was used to induce a rat model of MTLE. The hippocampus samples of 5 children with a pathologically confirmed hippocampal sclerosis who received surgical operation were collected as a human model (HM) group, and the hippocampus samples of 4 dead children (without organic lesion of the hippocampus) were collected by autopsy as a human control (HC) group. The expression of dynamin-1 and phosphor-dynamin-1 in the hippocampus of children and rats with MTLE was measured by Western blot and immunohistochemistry.

RESULTSThe Western blot showed that the expression of phosphor-dynamin-1 was significantly lower in the AS and CS groups than in the corresponding control groups (AC and CC groups) (P<0.05). The expression of phosphor-dynamin-1 was significantly lower in the HM group than in the HC group (P<0.05). There were no significant differences in the expression of dynamin-1 among the AS, LS and CS groups and between the HM and HC groups (P>0.05). The immunohistochemical results showed that phosphor-dynamin-1 was highly expressed in the cytoplasm of hippocampal neurons of AC, CC and HC groups, but its expression was significantly reduced in the AS, CS and HM groups (P<0.05).

CONCLUSIONSThe expression of phosphor-dynamin-1, not dynamin-1, is downregulated in the hippocampus of children and rats with MTLE during seizures, which suggests that the phosphorylation/dephosphorylation of dynamin-1 may be involved in the development of MTLE.

Animals ; Blotting, Western ; Child ; Dynamin I ; analysis ; metabolism ; Epilepsy, Temporal Lobe ; metabolism ; Female ; Hippocampus ; chemistry ; metabolism ; Humans ; Immunohistochemistry ; Male ; Phosphorylation ; Rats ; Rats, Sprague-Dawley

To evaluate the expression of cytoplasmic CD79a (CyCD79a) and other commonly used B-lymphoid immunomarkers including cytoplasmic CD22 (CyCD22), CD19, CD20 and CD10 in various acute leukemia cells and to define the most sensitive and specific markers in the diagnosis of precursor B-cell acute lymphoblastic leukemia (pB-ALL), the immunophenotypic data from 221 de novo adult and pediatric acute leukemia patients as studied using multi-parameter flow cytometry in addition to routine morphologic and enzyme cytochemical assay, were retrospectively analyzed. Cytogenetic and/or molecular biological data in all 45 cases of acute promyelocytic leukemia (APL) and 13 cases of acute leukemia suspected as AML with the fusion genes such as AML1/ETO and CBFbeta/MYH11 were investigated. The results showed that CyCD79a and CyCD22 were the most sensitive and specific markers respectively for pB-ALL. Expression of CyCD79a was seen in 100% of 58 cases of pB-ALL. At the same time, none (0%) of all 147 cases of acute myeloid leukemia (AML) and 15 cases of precursor T-cell acute leukemia (pT-ALL) was positive for CyCD22. The conclusion is made that united detection of CyCD79a and CyCD22 is the optimal immune combination for the diagnosis pB-ALL and the distinguishing pB-ALL with AML and pT-ALL.
Acute Disease ; B-Lymphocytes ; immunology ; Biomarkers, Tumor ; immunology ; CD79 Antigens ; immunology ; Cytoplasm ; immunology ; Flow Cytometry ; Humans ; Immunophenotyping ; Karyotyping ; Leukemia, Myeloid ; genetics ; immunology ; pathology ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ; immunology ; metabolism ; pathology ; Sialic Acid Binding Ig-like Lectin 2 ; immunology

This study was aimed to investigate the effect of recombinant mutant human TNF-related apoptosis-inducing ligand (rmhTRAIL) combined with As(2)O(3) on inducing apoptosis of adriamycin-resistant leukemia cell line K562/A02 (mdr-1(+)). The morphologic changes of cells treated with rmhTRAIL were observed by inverted microscope, taking adriamycin-sensitive cell line K562 (mdr-1(-)) as control; the inhibitory rate of cell proliferation after being treated with rmhTRAIL, As(2)O(3) alone or combined was assayed by MTT method; the apoptosis peaks of K562/AO2 and K562 were quantitatively detected by flow cytometry with PI staining after being treated with rmhTRAIL, As(2)O(3) alone or in combination. The results indicated that the inhibition effect of rmhTRAIL and As(2)O(3) in combination on K562/AO2 and K562 cells was higher than that of riTRAIL and As(2)O(3) alone (p < 0.01), rmhTRAIL combined with As(2)O(3) had synergistic effect in killing K562/AO2 and K562 cells by king's formula. The apoptosis rates of K562/AO2 and K562 cells were 34.93 +/- 0.10% and 10.53 +/- 0.16% (p < 0.01), as well as 5.95 +/- 0.07%, and 3.50 +/- 0.01% (p < 0.05), 50.95 +/- 0.91% and 20.75 +/- 0.95% (p < 0.05) respectively when their cells were treated by rmhTRAIL and As(2)O(3) alone. The apoptosis rate in K562/AO2 group was higher than that in K562 group. It is concluded that rmhTRAIL can induce K562/A02 and K562 cell apoptosis; rmhTRAIL combined As(2)O(3) had synergistic effects; the efficacy of on rmhTRAIL or As(2)O(3) inducing K562/AO2 cell apoptosis is higher than that on their parental cell line K562.
Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drug Synergism ; Humans ; K562 Cells ; Oxides ; pharmacology ; Recombinant Proteins ; pharmacology ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology

OBJECTIVETo investigate the methylation of CpG island in the SHP-1 gene promoter and its significance in lymphoma. To evaluate the effects of As2O3 on demethylation of SHP-1 in human lymphoma cell line T2 and on proliferation of T2 cells.

METHODST2 cells were treated with AsO3. Methylation specific PCR was used to detected the status of SHP-1 methylation in newly diagnosed lymphoma tissues and the T2 cells. The mRNA and protein expression of SHP-1 were determined by FQ-PCR and Western blot. The expression of phospha-c-kit was examined by Westren blot. MTT and flow cytometry were used to determine the growth and apoptosis in T2 cells.

RESULTST2 cells contained completely methylated SHP-1. Furthermore, there was constitutive c-kit phosphorylation. The expression of SHP-1 was recoverd when the cells exposed to AsO3, and concomitant with increasing SHP-1, a parallel down-regulation of phosphorylated c-kit occurred, so that by day 3 phosphorylated c-kit was barely detectable. As2O3 inhibited the cell growth, and the effects were dose- and time-dependent. As2O3 also increased apoptosis rate of T2 cells in a dose- and time-dependent manner, too, and on the 1, 2, 3 d treatment with AsO3 (2.5 micromol/L), the apoptosis rates were 6.12%, 26.53%, 50.90%, respectively. The frequency of methylation in SHP-1 gene promoter in lymphoma tissues was 87.5% (28/32). In the control group, however, 12 specimens of benign lymph node proliferation showed no methylation in CpG island of SHP-1 gene promoter.

CONCLUSIONHypermethylation of SHP-1 gene promoter in lymphoma indicates the inactivation of SHP-1 gene and its possible role in the tumorigenesis of lymphoma. As2O3 can effectively cause demethylation and inhibit the growth of tumor by reactivating the SHP-1 gene transcription. SHP-1 methylation leading to epigenetic activation of c-kit may have a tentative role in the pathogenesis of lymphoma. Therefore, As2O3 is potentially useful in the treatment of lymphoma as a demethylating agent.

Antineoplastic Agents ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; administration & dosage ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; CpG Islands ; DNA Methylation ; drug effects ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Neoplastic ; Humans ; Lymphoma ; metabolism ; pathology ; Lymphoma, Non-Hodgkin ; genetics ; metabolism ; pathology ; Oxides ; administration & dosage ; pharmacology ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; genetics ; metabolism ; Proto-Oncogene Proteins c-kit ; metabolism ; RNA, Messenger ; metabolism ; Transcriptional Activation ; drug effects ; Up-Regulation

In order to investigate the anti-tumor activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and the mechanism underlying the cell proliferation and apoptosis modulated in myeloma cells, the effects of mevastatin, an HMG-CoA reductase inhibitor, on cell growth, cell cycle progression and apoptosis in U266 human multiple myeloma (MM) cell line in vitro were explored by MTT colorimetric assay, morphologic observation, flow cytometry, DNA gel electrophoresis, and RT-PCR. The results demonstrated that mevastatin inhibited the growth of U266 cells in time- and dose-dependent manners. Cell cycle analysis showed that U266 cells underwent G(0)/G(1) arrest under exposure to mevastatin, but it did not affect p27 expression at both mRNA and protein level. Morphologic observations revealed cytoplasm shrinkage, nuclear condensation and fragmentation in mevastatin-treated cells, and fraction of annexin V(+)PI(-) cells increased significantly in the presence of the agent as determined by flow cytometric assay. In addition, mevastatin caused the collapse of mitochondrial transmembrane potential (Deltapsim), induced DNA fragmentation, and down-regulated the mRNA expression of bcl-2. The growth-inhibitory, cell cycle arresting, and proapoptotic effects of mevastatin in U266 cells could be effectively reversed by the addition of mevalonate (MVA), the immediate endproduct of the reaction catalyzed by HMG-CoA reductase. It is concluded that mevastatin suppresses proliferation by inducing G(0)/G(1) phase arrest and triggering apoptosis via down-regulation of bcl-2 and reduction of Deltapsim, which may be attributed to the inhibition of MVA pathway by mevastatin. Statins including mevastatin may find their future application in the treatment of MM.
Apoptosis ; drug effects ; Cell Division ; drug effects ; Cell Line, Tumor ; G1 Phase ; drug effects ; Genes, bcl-2 ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; Lovastatin ; analogs & derivatives ; pharmacology ; Multiple Myeloma ; drug therapy ; pathology

In order to investigate the role and the mechanism of protein tyrosine phosphatase (PTPase) signaling pathway in the regulation of proliferation, cell cycle and apoptosis in lymphoma cells, the effects of sodium orthovanadate, Na(3)VO(4), a specific PTPase inhibitor, were explored on Raji lymphoblast-like cell line by MTT assay and CFU-Raji culture, morphologic observation, DNA gel electrophoresis, FCM and RT-PCR. Results showed that MTT assay and CFU-Raji culture demonstrated that sodium or thovanadate inhibited the growth of Raji cells in a concentration-dependent fashion; morphologic observations showed that Raji cells exhibited cytoplasm shrinkage, cytoplasm membrane blebbing, nuclear fragmentation and chromatin condensation forming crescents along nuclear membrane characteristic of apoptosis in the presence of Na(3)VO(4); DNA gel electrophoresis revealed typical DNA ladder reminiscent of DNA cleavage at internucleosomal sites in Na(3)VO(4) treated cells; FCM and RT-PCR indicated that Na(3)VO(4) intervention increased the fraction of annexin V(+) PI(-) cells, reduced the value of mitochondrial transmembrane potential, induced G(2)/M arrest and down-regulated the expression of Bcl-2 and cyclin B1 at both mRNA and protein level in a concentration-dependent manner. It was concluded that PTPase pathway might be implicated in the regulation of cell proliferation, cell cycle and apoptosis, and PTPase specific inhibitor Na(3)VO(4) could induce Raji cell growth inhibition, G(2)/M arrest and apoptosis via down-regulation of Bcl-2 and cyclin B1, and reduction of mitochondrial transmembrane potential.
Apoptosis ; drug effects ; Cell Division ; drug effects ; Cyclin B ; analysis ; Cyclin B1 ; Enzyme Inhibitors ; pharmacology ; Humans ; Leukocyte Common Antigens ; analysis ; Membrane Potentials ; drug effects ; Mitochondria ; drug effects ; physiology ; Protein Tyrosine Phosphatases ; antagonists & inhibitors ; Vanadates ; pharmacology

The present study was purposed to investigate the inhibition effect of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) on growth of RPMI8226 cells and adhesion between RPMI8226 cells and bone marrow stroma cells (BMSC), and to explore its mechanism as well. The inhibition effects of TRAIL on cells growth and adhesion were assayed by MTT; cell apoptosis was detected by Annexin V and PI; expression of genes bax, bcl-2, mcl-1, CARP1, CARP2, XIAP and cFLIP were determined by semi-quantitative RT-PCR; apoptosis-related protein expression was detected by Western blot. The results showed that TRAIL inhibited the proliferation of RPMI8226 cells in dose- and time-dependent manners. TRAIL induced apoptosis in RPMI8226 cells, the expression level of genes bcl-2, mcl-1, CARP1, CARP2, XIAP and cFLIP decreased, while the expression level of Bax increased, but the expression level of caspase-3 and NF-kappaB P65(RelA) proteins decreased. Moreover, TRAIL up-regulated the expression level of adherent molecule CXCR4 in RPMI8226 cells significantly. It is concluded that TRAIL up-regulated the expression level of adherent molecule CXCR4 in RPMI8226 cells significantly, and induced the apoptosis of RPMI8226 cells. Growth inhibition effect of TRAIL on RPMI8226 cells is in dose- and time-dependent manners.
Apoptosis ; drug effects ; Bone Marrow Cells ; drug effects ; metabolism ; Cell Adhesion ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Multiple Myeloma ; metabolism ; pathology ; TNF-Related Apoptosis-Inducing Ligand ; genetics ; pharmacology