Effect of bcl-2 siRNA on apoptosis of Burkitt's lymphoma cell line CA46 / 中国实验血液学杂志

The aim of this study was to investigate the effect of bcl-2 siRNA on bcl-2 gene expression and apoptosis of lymphoma cell line CA46. A siRNA was designed and synthesized. Then siRNA was transfected into CA46 cells by cationic liposome. At 48 hours after transfection, apoptosis and mitochondria transmembrane potential of CA46 cells were detected by flow cytometry, the expression of bcl-2 mRNA and BCL-2 protein in CA46 cells were detected by RT-PCR and flow cytometry respectively. The results showed that at 48 hours after transfection, apoptosis of CA46 cells occurred, mitochondria transmembrane potential changed. The expression of bcl-2 mRNA and BCL-2 protein in CA46 cells decreased significantly. In conclusion, bcl-2 siRNA depresses the expression of bcl-2 gene in CA46 cells specifically, then changes the mitochondria transmembrane potential, resulting in apoptosis of CA46 cells.

Effect of emodin on induction of apoptosis in jurkat cells and its possible mechanisms / 中国实验血液学杂志

The aim of study was to investigate the effect of a traditional Chinese medicine, emodin, on proliferation and apoptosis in T lymphocytic leukemic cell line Jurkat and its mechanisms. Cell proliferation inhibition was detected by MTT assay. Cell apoptosis was measured by DNA ladder and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. The expressions of related proteins and caspase family members were determined by Western blot. The results showed that emodin inhibited proliferation in Jurkat cells, with an IC50 about 20 micromol/L and induced cell apoptosis in both time-and dose-dependent manners. The expressions of proliferation-related protein C-MYC, hTERT and apoptosis-related protein BCL-2 were down-regulated in a time dependent manner after the treatment with emodin. The expressions of procaspase-3, -8 and -9 all decreased while activated caspase-3 and PARP expressions were up-regulated. It is concluded that emodin can remarkably inhibit cell proliferation and induce apoptosis in Jurkat cells. The down-regulation of proliferation-related proteins C-MYC, hTERT and apoptosis-related protein BCL-2 expressions and activation of caspase cascade may be involved in the process of apoptosis.

Emodin induces leukemic HL-60 cells apoptosis probably by inhibiting Akt signal pathway / 药学学报

This study is to investigate the effect of emodin on inducing human myeloid leukemia cell line HL-60 apoptosis and the role of Akt signal pathway in the apoptosis. HL-60 cells were exposed to various dosages of emodin. MTT assay was used to detect HL-60 cell proliferation. Distribution of HL-60 cells in cell cycle was analyzed by flow cytometry and cell apoptosis was observed by MitoCapture apoptosis detection. The protein expressions of Akt signal pathway were detected by Western blotting. The result showed that emodin remarkably inhibited the cell proliferation. The IC50 value for 48 h treatment was about 20 micromol x L(-1). Apoptosis in HL-60 cells could be efficiently induced by emodin in a dose dependent manner and cells were arrested at G0/G1. The expressions of Akt, p-Akt, IkappaB-alpha, p-IkappaB-alpha, p65, p-p65, mTOR and p-mTOR in Akt signal pathway were downregulated after emodin treatment. It can be concluded that emodin could efficiently induce growth inhibition and apoptosis in HL-60 cells. Akt signal pathway may be involved in this process.

Inhibitory effects of emodin on drug-resistant HL-60/ADR cell proliferation and its induction of apoptosis / 中国实验血液学杂志

The study was aimed to investigate the effects of emodin on the proliferation and apoptosis of adriamycin-resistant HL-60/ADR cells, and to explore the underlying mechanism. The cell viability and colony formation were detected by MTT assay and colony formation assay respectively. Apoptotic cells were tested by means of cell cycle analysis, mitochondrial transmembrane potential levels, caspase-3 activity detection, Annexin V FITC/PI staining and TUNEL labeling. RT-PCR was used to analyze the bcl-2 and c-myc mRNA expressions. The protein expressions of Bcl-2, c-Myc and caspase-3 precursor were determined by Western blot. The results showed that HL-60/ADR cell growth was significantly inhibited by emodin in dose and time dependent manners. Cell colony formation obviously decreased with IC50 5.79 micromol/L. G0/G1 phase cell population increased while G2/M phase cells decreased in 40 and 80 micromol/L groups compared with control group (p < 0.01), and no significant difference of cell cycle was observed in 20 micromol/L group (p > 0.05). The typical hypo-diploid peak (apoptotic peak) appeared in each dose group. The levels of mitochondrial transmembrane potential of HL-60/ADR cells decreased and caspase-3 activity increased when incubated with emodin for 12 and 24 hours respectively. Apoptosis occurred in a dose-dependent manner, and its earlier and later stages were identified by Annexin-V FITC/PI staining and TUNEL labeling methods respectively. The expressions of bcl-2, c-myc mRNA and Bcl-2, c-Myc, caspase-3 precursor protein were all down-regulated in a time-dependent manner after treatment with emodin at different times. It is concluded that emodin efficiently inhibits growth and induces apoptosis on HL-60/ADR cells, which may be related with the down-regulation of mitochondrial transmembrane potential and expressions of bcl-2 and c-myc, as well as up-regulation of caspase-3 activity.

A novel bcl-2 antisense oligodeoxynucleotide F951 increases sensitivity of HL-60 cells to Ara-C / 中国实验血液学杂志

To investigate whether F951, a novel bcl-2 antisense oligodeoxynucleotide, increases the sensitivity of HL-60 cells to Ara-C, HL-60 cells were cultured with F951 in different doses alone or with F951 combined with low-dose Ara-C; the proliferation of HL-60 cells was assayed by MTT and trypan blue exclusion test; expression of Bcl-2 protein and its mRNA were measured by FACS and RT-PCR, respectively; the apoptotic cells were detected by DNA ladder and TUNEL assay. The results showed that F951 combined with low dose Ara-C revealed stronger effects in the aspects of inhibiting the HL-60 cells proliferation than in different doses of F951 alone or Ara-C alone. HL-60 cells treated with F951 + Ara-C had significantly lower trypan blue exclusion rate than that treated with Ara-C alone. The inhibition rates of HL-60 cells treated with FNS, Ara-C, F951 and F951 + Ara-C were -2.8%, 27.63%, 37.66%, 57.24%, respectively. F951 significantly down-regulated the expression of bcl-2 mRNA and protein in HL-60 cells. HL-60 cells treated with F951 + Ara-C showed more apparent DNA ladder and more apoptotic cells. It is concluded that F951 can inhibit bcl-2 gene expression and enhance the cytotoxicity of Ara-C through promoting apoptosis in HL-60 cells, hence increases the antitumor effect of Ara-C.

Bcl-2 antisense oligonucleotides suppress HL-60 cell growth in a SCID mouse mode / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the effects of bcl-2 antisense phosphorothioate oligonucleotides (ASPO) on suppression of HL-60 cell growth in SCID mice and to investigate the feasibility of purging leukemia cells plus bcl-2 ASPO used in vitro.</p><p><b>METHODS</b>1 x 10(7) viable HL-60 cells were treated with 10 micro mol/L bcl-2 ASPO seven days before the intraperitoneal (IP) inoculation to the SCID mice, Treatment with sense oligonucleotides (SPO) was similar as for the controls. 35 days after the inoculation, all the SCID mice of both groups were sacrificed and their peripheral blood, bone marrow, liver and spleen were examined using half nested RT-PCR and histopathology for detecting the appearance and distribution of the HL-60 cells treated beforehand with antisense or sense oligonucleotides respectively.</p><p><b>RESULTS</b>ASPO could down regulate the expression of bcl-2 resulting in both inhibition of growth and induction of apoptosis in treated HL-60 cells, which failed to develop leukemia in SCID mice at all. However, SPO treated HL-60 cells still behaved their own ways and proliferated agressively, and developed leukemia at last.</p><p><b>CONCLUSION</b>The bcl-2 ASPO enables to suppress HL-60 cell growth and prevent the development of leukemia in the SCID mice. The purging leukemia cells used are seemed liable in inhibiting the development of leukemia in SCID mouse model.</p>

Effect of endogenous TGF-beta1 and TNF-alpha on the As(2)O(3) inducing apoptosis of HL-60 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effect of endogenous TGF-beta(1) and TNF-alpha on As(2)O(3) inducing apoptosis of HL-60 cells.</p><p><b>METHODS</b>The expressions of endogenous TGF-beta(1) and TNF-alpha in apoptotic HL-60 cells induced by As(2)O(3) were assayed by RT-PCR, quantitative RT-PCR, ELISA, DNA fragmentation and TUNEL. The effect of TGF-beta(1) and TNF-alpha antisense phosphorothioate oligodeoxynucleotides (PSODNs) on As(2)O(3) inducing apoptotic HL-60 cells was further studied.</p><p><b>RESULTS</b>(1) Expressions of endogenous TGF-beta(1) and TNF-alpha were significantly up-regulated in As(2)O(3) inducing apoptotic HL-60 cells (from 13,546 +/- 124 and 497,216 +/- 187 before treatment to 23,273 +/- 229 and 674,217 +/- 189 after treatment, respectively), accompanied with down-regulated bcl-2 mRNA expression (from 10,424 +/- 274 before treatment to 3,361 +/- 89 after treatment). (2) TGF-beta(1) and TNF-alpha antisense PSODNs could rescue As(2)O(3) induced apoptosis of HL-60 cells, with a restoration of bcl-2 gene expression.</p><p><b>CONCLUSIONS</b>Endogenous TGF-beta(1) and TNF-alpha played an important role in As(2)O(3) inducing HL-60 cells apoptosis through down-regulation of bcl-2 expression.</p>

New insight into the mechanism of p53 inducing leukemia cell apoptosis / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the expression changes of intrinsic cytokines TGF-beta(1) and TNF-alpha, telomerase activity and bcl-2 during ongoing apoptosis of HL-60 and K562 cells induced by p53.</p><p><b>METHODS</b>pN53cG (Val135), a temperature sensitive p53 mutant, which behaved like wild type p53 (wt-p53) at 32.5 degrees C, were introduced into p53-null HL-60 and K562 cells respectively by lipofectin. In the presence of G418, HL-60-pN53cG and K562 pN53cG clones expressing p53 protein were selected. The ongoing expression of intrinsic cytokines (TGF-beta(1) and TNF-alpha), bcl-2 oncogene and hTERT mRNA during the apoptosis of HL-60 and K562 cells induced by p53 and the effects of exogenous p53 gene, TGF-beta(1) and TNF-alpha antisense PS-ODNS on the apoptosis of HL-60 and K562 cells and the expression of bcl-2 were studied by RT-PCR, quantitative RT-PCR, DNA fragmentation, TdT-mediated dUTP nick end labeling (TUNEL) and flow cytometery. The levels of secreted TGF-beta(1) and telomerase activity were detected by ELISA and PCR-ELISA, respectively.</p><p><b>RESULTS</b>(1) The expressions of intrinsic TGF-beta(1) and TNF-alpha mRNA were up-regulated, while that of bcl-2 and hTERT down-regulated. The levels of TGF-beta(1) in the supernatant of HL-60 and K562 cells were increased, and the level of telomerase activity decreased. (2) Antisense PS-ODNS of TGF-beta(1) and TNF-alpha could obviously inhibit the p53 inducing cell apoptosis, and restore bcl-2 mRNA and protein to pre-treated level.</p><p><b>CONCLUSIONS</b>Exogenous p53 induces leukemia cell apoptosis via up-regulating the expression of intrinsic TGF-beta(1) and TNF-alpha and down-regulating the expression of hTERT and bcl-2.</p>

Effect of p53 gene on telomerase activity and hTERT gene expression in HL-60 cells / 中国实验血液学杂志

To investigate the change of telomerase activity and human telomerase reverse transcriptase (hTERT) gene expression in HL-60 cells transfected with wild type p53 gene, wild type p53 gene was introduced into HL-60 cells by Lipofectin transfection. Apoptosis was analyzed by TUNEL assay. Telomerase activity and the level of hTERT mRNA were detected by telomeric repeat amplification protocol (TRAP)-ELISA and RT-PCR, respectively. The results showed that the apoptotic rate of HL-60-pN53cG cells was 8.3% and 21.0% respectively after cultured at 32.5 degrees C for 24 h and 72 h. The level of hTERT mRNA was decreased to 68.4% and 55.8% and telomerase activity to 27.3% and 8.9% of control value in HL-60-pN53cG cells at the same points. In conclusions, hTERT mRNA and telomerase activity were down-regulated in HL-60 cells transfected with p53 gene. This may be one of mechanisms of apoptosis induced by wild type p53 gene.

Effects of SCL antisense ooligonucleotides on K562 and CEM cell lines / 中国实验血液学杂志

The stem cell leukemia (SCL) gene is a new oncogene related with leukemogenesis. To explore the effects of antisense oligonucleotides of SCL on leukemic cells, SCL antisense phosphorothioate oligodeoxynucleotides (AS-PS-ODN) were used to treat K562 and CEM leukemic cell lines to observe the effects on proliferation, differentiation, apoptosis and SCL mRNA expression in the cells. The results showed that incubation of K562 or CEM cells with AS-PS-ODN at different concentrations led to inhibition of cell proliferation, and the inhibitory effects varied with the incubation time. The positive rate of benzidine staining in K562 cells increased significantly after the inhibition with AS-PS-ODN, compared with S-PS-ODN treatment. The characteristics of apoptosis were observed in K562 cells treated with AS-PS-ODN, but not in CEM cells. Expression of SCL mRNA in K562 and CEM cells and SIL-SCL mRNA in CEM cells decreased after incubation of AS-PS-ODN. It is concluded that SCL AS-PS-ODN inhibits specifically the proliferation of K562 and CEM cells, also decreases the level of SCL and SIL-SCL mRNA expression. AS-PS-ODN enhances erythroid differentiation and induces premature apoptosis in K562 cells.

Effects of Exogenous Wild-Type p53 Gene on K562 Cells / 中国实验血液学杂志

To investigate the effects of wt-p53 gene on proliferation and differentiation of K562 cells and to explore the feasibility of wt-p53 in leukemia gene therapy, pC53-SN(3), containing wt-p53 cDNA, and temperature-sensitive p53 mutant pN53cG(Val135) which behaved like wt-p53 at 32.5 degrees C, were introduced into p53-null K562 cells respectively by lipofectin mediated DNA transfection. In the presence of G418, K-SN(3) and K-pN53cG clones expressing P53 protein were selected. The effects of exogenous wt-p53 gene on the proliferation and differentiation of K562 cells were studied by detection of cell growth curves, leukemic colony formation, cell cycle analysis and DNA fragmentation, TdT-mediated dUTP nick end labeling (TUNEL) and benzidine staining. The results showed: (1) The level of p53 mRNA in K-SN(3) cells was lower than that in K-pN53cG cells by RT-PCR. (2) K-SN(3) and K-pN53cG(32.5 degrees C) cells proliferated more slowly than the control K562 cells, and their colony formation was obviously suppressed. The cells in G(0)/G(1) phase increased, and the cells in S phase decreased. These features were more obvious in K-pN53cG(32.5 degrees C). (3) K-pN53cG(32.5 degrees C) showed the feature of apoptosis and K-SN(3) showed the characteristics of erythroid lineage differentiation. It was indicated that exogenous of wt-p53 was capable of inhibiting the proliferation of K562 cells and inducing apoptosis of the cells at higher p53 level and interestingly, inducing the cells differentiation on erythroid lineage at lower p53 level.

c-myc Antisense Oligodeoxynucleotides Induce Apoptosis of Human Myeloid Leukemia Cell Line HL-60 / 中国实验血液学杂志

In order to study the effects of c-myc antisense phosphorothioate oligodeoxynucleotide in inducing apoptosis of HL-60 cells, the expression of c-myc mRNA was determined by RT-PCR, the morphologic signs of apoptotic cells were observed by transmission electron microscopy, the proportion of apoptotic cells was detected by flow cytometry, and the DNA fragments were analysed by agarose gel electrophoresis. Results of RT-PCR showed marked decrease of c-myc mRNA expression in AspoI and II treated cells. The level of c-Myc protein was decreased 23.8% and 45.4%, respectively, in cells treated with 5 and 10 micro mol/L AspoI, and 38.4% after treatment of 10 micro mol/L AspoII. The apoptotic rates were 23.97% and 52.6% after 10 micro mol/L AspoI treatment and 28.8% and 45.19% after treatment with AspoII 10 micro mol/L for 48 and 72 hours, respectively. while apoptotic cells did not apear in control and sense oligodeoxynucleotide groups. Electron microscopy observation showed the characteritics of apoptosis. A ladder like pattern of DNA fragments was demonstrated on electrophoretogram. The results suggst that c-myc antisense oligodeoxynucleotides could be highly specific gene agents that can suppress the level of c-myc mRNA, decrease the c-Myc proteins and induce apoptosis of HL-60 cells.