Effect of Metformin on Proliferation of Multiple Myeloma Cells / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of metformin on proliferation and apoptosis in multiple myeloma cell line RPMI8226 and U266, and to clarify the molecular mechanism of proliferation inhibition and apoptosis induced by metformin.</p><p><b>METHODS</b>RPMI8226, U266 cells were treated with 0, 5, 10, 20, 40, 80 mmol/L of metformin for 24, 48 and 72 hours, then the inhibition rate was detected by CCK-8; RPMI8226 cells were treated with 0, 10, 20, 40 mmol/L of metformin for 48 hours, the apoptosis rates were detected by flow cytometry with Annexin-V-FITC/PI double staining; RPMI8226 cells were treated with 0, 5, 10, 20 mmol/L of metformin for 48 hours, the expressions of Caspase-3, PARP, STAT3, p-STAT3, BCL-2, Cyclin D1 and P21 were detected by Western blot.</p><p><b>RESULTS</b>The inhibition rate increased in RPMI8226 and U266 cells treated with metformin in the dose- (r=0.982, r=0.967, P<0.05) and time-dependent (r=0.956, r=0.962, P<0.05) manner; the apoptosis rate increased(r=0.976, P<0.05) in RPMI8226 cells treated with metformin; it also was found that procaspase-3 was degraded and PARP was cleaved when treated with metformin. Proliferation inhibition and apoptosis of RPMI8226 cells were related with inhibition of STAT3 phosphorylation, down-regulation of BCL-2 and Cyclin D1, and up-regulation of P21.</p><p><b>CONCLUSION</b>Metformin can inhibit the proliferation and induce apoptosis of RPMI8226 and U266 cell lines, which may be related to down-regulation of STAT3 signal transduction pathway.</p>

Effect of PKF118-310 on Cell Cycle and Proliferation of K562 Cells and Its Mechanism / 中国实验血液学杂志

<p><b>UNLABELLED</b>Objetive: To investigate the effects of PKF118-310 on cell cycle and proliferation of K562 cell lines and its mechanism.</p><p><b>METHODS</b>After treatment of PKF118-310 with different concentration, the proliferation inhibition on K562 cell lines was detected by MTT, the existance of β-catenin and TCF-4 in the cells was observed by immunohistochemistry. The change of the cell cycle was detected by flow cytometry. The expressions of caspase-3, β-catenin, TCF and BCL-9 were detected by Western blot.</p><p><b>RESULTS</b>PKF118-310 can inhibit the proliferation of K562 cell line by S phase blocking. The β-catenin and TCF in the cells were observed by immunohistochemistry. After treating this cell line with PKF118-310 of different concentrations for 72 h, the expression level of caspase-3 increased, the expression levels of β-catenin, TCF and BCL-9 significantly decreased.</p><p><b>CONCLUSION</b>PKF118-310 induces cycle arest of K562 cells at the S phase and inhibits the proliferation of these cells through decreasing β-catenin/TCF/BCL-9 thrascriptional activity.</p>

Mechanism of cinnamic aldehyde-inducing apoptosis of chronic myeloid leukemic cells in vitro / 中国实验血液学杂志

The aim of this study was to investigate the apoptosis-inducing effect of cinnamic aldehyde (CA) on chronic myeloid leukemic (CML) cells and its mechanism. K562 cells and primary bone marrow mononuclear cells (MNC) from patients with CML were treated by various concentrations of CA. Flow cytometry was employed to measure the apoptosis of K562 cells and primary CML bone marrow MNC. Western blot was used to determine the expression of C-MYC and the phosphorylation of CrkL in K562 cells, and real-time polymerase chain reaction (real-time PCR) was used to quantify the expression of BCR-ABL mRNA in K562 cells. The results indicated that CA induced the apoptosis of K562 cells in a time- and dose-dependent manner. CA induced apoptosis of CML MNC dose-dependently. CA inhibited the expression of BCR-ABL mRNA and C-MYC, reduced CrkL phosphorylation levels in K562 cells. It is concluded that CA induces apoptosis of CML cells in vitro. Down-regulation of the expression and function of BCR-ABL may be one of its most important anti-leukemia mechanisms.

Effect of rapamycin on proliferation, apoptosis and regulation of chemokine receptor CXCR4 in RPMI8226 cells / 中国实验血液学杂志

This study was purposed to investigate the effect of rapamycin on proliferation, apoptosis, cell cycle progression and the regulation of chemokine receptor CXCR4 on RPMI8226 cells. Different concentrations of rapamycin were used to treat the multiple myeloma cell line RPMI8226 for different times. The proliferation of the cells was detected by MTT assay; the apoptosis rate and cell cycle were determined by flow cytometry (FCM); apoptosis of cells was observed by inverted microscopy; the cylin D1, CXCR4 and mTOR mRNA expressions were detected by RT-PCR or FQ-PCR after treating RPMI8226 cells with different concentrations of rapamycin. The results indicated that the rapamycin could inhibit the proliferation of RPMI8226 cells and induce their apoptosis. The cell cycle was arrested at the G(0)/G(1) phase. PCR results showed the down-regulation of mTOR, cyclin D1 and mTOR mRNA expressions after treating RPMI8226 cells with different concentrations of rapamycin for 24 hours. It is concluded that the rapamycin significantly inhibits the growth of RPMI8226 cells in a dose-and time-dependent mannes and induce cell apoptosis. Cell cycle arrests at the G(0)/G(1) phase, may be due to the down-regulation of the mTOR and cyclin D1 expressions. In additions, the down-regulation of CXCR4 mRNA expression is correlated with the reduction of adhesion between myeloma cells and stromal cells.

Mutation analysis of SHIP gene in acute leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>The SH2 domain containing inositol 5'-phosphatase (SHIP) is predominately expressed in hematopoietic cells, and is a crucial negative regulator in the development of hematopoietic cells. This paper is to evaluate the role of the SHIP gene in human leukemogenesis.</p><p><b>METHODS</b>Expression of SHIP gene in bone marrow and/or peripheral blood from 32 patients with acute myeloid leukemia (AML), 9 with acute lymphoblastic leukemia (ALL), as well as human hematopoietic cell lines was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), single strand conformational polymorphism (SSCP) and DNA sequencing.</p><p><b>RESULTS</b>RT-PCR showed that all samples expressed SHIP gene. Mutations of SHIP gene were detected in 7 (22%) of 32 AML patients and one (12%) of 9 ALL patients. Interestingly, two missense mutations that had been observed in a AML patient at diagnosis disappeared after complete remission (CR). In addition, in vitro Akt phosphorylation was prolonged and increased following IL-3 stimulation of this patient's cells.</p><p><b>CONCLUSION</b>Our data demonstrate for the first time the mutation of SHIP gene in acute leukemia and suggest a possible role of the mutation of this gene in the development of acute leukemia. SHIP may serve as a tumor suppressor by negatively regulating the PI3K/Akt signaling pathway in hematopoietic cells.</p>

Mutation analysis of hematopoietic cell phosphatase gene in acute leukemia / 中国实验血液学杂志

The hematopoietic cell phosphatase (HCP or SHP-1), the SH2 domain contain protein tyrosine phosphatase, is a crucial negative regulator in the process of hematopoietic cell development, proliferation and receptor-mediated mitogenic signaling pathways, and its mutation is responsible for the over-expansion and inappropriate activation of myelomonocytic population in motheaten mice. The aim of the study was to evaluate the role of the HCP gene in leukemogenesis. Bone marrow and/or peripheral blood from 32 acute myeloid leukemia (AML) patients, 9 acute lymphocytic leukemia (ALL) patients, 8 leukemia cell lines and 50 normal controls were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) based on single strand conformation polymorphism (SSCP) and sequencing. RT-PCR showed that all samples expressed HCP gene, only one missense mutation at codon 225 (AAC to AGC, Asn to Ser) within N-terminal SH2 domain was found in an ALL patient. In addition, four polymorphic base substitutions were detected in codon 69, 85, 86 and 266, respectively. In conclusion, mutation of HCP gene is an infrequent genetic aberration which may only play a role in pathogenesis of a small part of leukemia, however, its significance needs to be further clarified.

In vitro effects of mevastatin on the proliferation and apoptosis in human multiple myeloma cell line U266 / 中国实验血液学杂志

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.

Mutation analysis of SHIP gene in acute leukemia / 中国实验血液学杂志

The SH2 domain containing inositol 5'-phosphatase (SHIP) was initially described as a 145 kD protein phosphorylated on tyrosines upon growth factor and cytokine stimulation. SHIP is predominately expressed in hematopoietic cells, and is a crucial negative regulator in the development of hematopoietic cells. To evaluate the role of the SHIP gene in human leukemogenesis, expression and mutation of SHIP gene in bone marrow and/or peripheral blood from 32 patients with acute myeloid leukemia (AML), 9 patients with acute lymphoblastic leukemia (ALL), as well as human hematopoietic cell lines were analyzed by reverse transcription-polymerase chain reaction (RT-PCR), single strand conformational polymorphism (SSCP) and sequencing. The RT-PCR showed that all samples expressed SHIP gene. Mutations of SHIP gene were detected in 7 out of 32 AML patients (22%) and one out of 9 ALL patients (12%). Interestingly, two missense mutations that had been observed in one AML patient at diagnosis disappeared after complete remission (CR). In addition, Akt phosphorylation was prolonged and increased following IL-3 stimulation in this patient sample. In conclusion, data of this study demonstrate the mutation of the SHIP gene in acute leukemia for the first time and suggest a possible role of the mutation of this gene in the development of acute leukemia. SHIP serves as a tumor suppressor by negatively regulating the PI3K/Akt signaling pathway in hematopoietic cells.

mitochondrial ceramidase overexpression up-regulates Bcl-2 protein level in K562 cells, probably through its metabolite sphingosine-1-phosphate / 中国实验血液学杂志

Recently, a mitochondrial ceramidase has been identified and cloned, whose mitochondrial localization strongly suggests the existence of an unexpected mitochondrial pathway of ceramide metabolism that may play a key role in mitochondrial functions, especially in the regulation of apoptosis. To explore the biological effect of mitochondrial ceramidase on cells, pcDNA 3.1/His-CDase plasmid, containing mitochondrial ceramidase cDNA sequence, was transducted into K562 cells mediated by liposome, and G418 was used to screen for positive colonies. A stable transfected K562 cell line was established and named as 'K562TC'. The difference between K562 and K562TC cells in chemotheraputic cytotoxicity response and serum-withdrawal resistance and Bcl-2 protein expression were evaluated by MTT assay, annexin V/PI test, flow cytometry or Western blotting, respectively. The results showed that although survival was comparable between K562 and K562TC cells after exposed to adriamycin, etoposide or arsenious acid, K562TC cells with elevated Bcl-2 protein expression level as identified by FCM or Western blotting revealed stronger resistance to apoptosis induced by serum withdrawal than their parental cells. Inhibition of mitochondrial ceramidase expression in K562TC cells by its specific antisense oligodeoxynucleotide was correlated with a decrease in Bcl-2 protein level. N, N-dimethylsphingosine, a sphingosine kinase inhibitor, depleted intracellular sphingosine-1-phosphate production, also abrogated Bcl-2 protein expression in K562TC cells, while Bcl-2 protein level in K562 cells was up-regulated by exogenous sphingosine-1-phosphate. It is concluded that mitochondrial ceramidase overexpression in K562 cells leads to markedly elevated level of Bcl-2 protein and results in more resistance to serum withdrawal. This effect is initiated not by sphingosine, the direct metabolite of mitochondrial ceramidase, but via sphingosine-1-phosphate, its phosphorylated form. This is the first evidence that mitochondrial ceramidase, through its sphingoid metabolite sphingosine-1-phosphate, up-regulates Bcl-2 protein expression in K562 cells.

Effects of bcl-2 antisense oligodeoxynucleotide on proliferation and apoptosis of Raji cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the in vitro antitumor activity of bcl-2 fully phosporothioated antisense oligodeoxynucleotide (bcl-2 ASODN) to malignant lymphoblastic cells.</p><p><b>METHODS</b>Proliferation and apoptosis of Raji cells incubated with bcl-2 ASODN were evaluated by MTT assay, flow cytometry (FCM) and electron microscopy, and the level of bcl-2 protein and mRNA expression were assessed by FCM and RT-PCR, respectively.</p><p><b>RESULTS</b>MTT assay demonstrated that bcl-2 ASODN could partially inhibit the growth of Raji cells. After incubated with ASODN for 48 hours, Raji cells exhibited characteristic morphologic changes of apoptosis, including cytoplasm membrane blebbing, chromatin condensation crescents formation and nuclear fragmentation. The apoptosis rate of Raji cells treated with 20 micromol/L bcl-2 ASON for 72 hrs was 43.86% which is significantly higher than that of control (10.05%). The bcl-2 ASODN induced apoptosis of Raji cells was accompanied by declined expression of bcl-2 mRNA, which decreased to 0.88% at 72 hrs and was significantly lower than that of control (79.54%).</p><p><b>CONCLUSION</b>bcl-2 ASODN induced Raji cells apoptosis by downregulating bcl-2 protein.</p>

Effects of aminophylline on proliferation and apoptosis in Raji lympho-blastoid cell line / 中国实验血液学杂志

The aim of this study was to investigate whether and how phosphodiesterase (PDE) inhibitors modulate the proliferation, cell cycle and apoptosis in lymphoma cells. The effects of aminophylline (AM), a non-specific PDE inhibitor, on Raji cells were explored in vitro. MTT assay, light and transmission electron microscopy and annexin V staining were used to observe cell proliferation, morphologic changes and apoptosis rate in AM-treated cells, and FCM and RT-PCR techniques were adopted to detect the effect on cell cycle, the expression of cyclin B1 and Bcl-2 and mitochondrial transmembrane potential in AM-treated cells. The results showed that AM inhibited the growth of Raji cells in a concentration-dependent manner. Morphologic observations showed apoptosis changes in AM-treated cells, including cytoplamic shrinkage, cytoplasmic bubbling, karyopyknosis and nuclear fragmentation. FCM and RT-PCR detection showed that AM intervention increased the fraction of annexin V(+) cells, reduced the value of mitochondrial transmembrane potential, induced S phase arrest, and down-regulated the expression of Bcl-2 at both mRNA and protein level and cyclin B1 protein in a concentration-dependent manner. It is concluded that PDE inhibitor aminophylline may induce Raji cell growth inhibition, S phase arrest, apoptosis via down-regulation of Bcl-2 and reduction of mitochondrial transmembrane potential.

Improved RT-PCR for detection of PML/RARalpha fusion gene in rapid diagnosis of acute promyelocytic leukemia / 中国实验血液学杂志

Detection of the PML/RARalpha fusion gene by RT-PCR in acute promyelocytic leukemia (APL) blasts is not only critical to commence promptly the specific therapy with all-trans retinoic acid (ATRA) or arsenic trioxide (As(2)O(3)), but also essential for the definition of PML breakpoint type and subsequent monitoring of minimal residual disease (MRD). The current PML/RARalpha amplification techniques with conventional nested PCR are laborious and time consuming, which fails to meet the requirements for rapid diagnosis of APL in clinical practice. Therefore, an easily handled RT-PCR methodology for the rapid and accurate amplification of PML/RARalpha fusion transcripts is needed. A modified one round RT-PCR protocol was described with a few variations which includes rapid extraction of high quality cellular total RNA, cDNA synthesis with random hexamer and M-MLV reverse transcriptase, optimal concentrations of MgCl(2) (1 mmol/L), PCR primers (0.4 micro mol/L) and Taq polymerase (0.01 U/ micro l), hot-start procedure, and concomitant amplification of PML/RARalpha fusion gene and RARalpha internal control under the identical thermocycle parameters. The results in 40 patients with newly diagnosed APL showed that the improved RT-PCR protocol allowed the rapid detection of PML/RARalpha fusion gene and the accurate discrimination of its transcript types, and simultaneous amplification of RARalpha internal control under the identical program in less than 6 hours. There were no false positive or negative results found with the assay. In conclusion, the assay reported here is proved to be a simple, easily handled, and highly specific procedure for the diagnosis of APL cases, particularly those requiring such urgent therapeutic intervention as ATRA or As(2)O(3) and meriting its further application in APL management.

Effects of sodium orthovanadate on proliferation and apoptosis in raji cells and its mechanism / 中国实验血液学杂志

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.