Silencing of Bcl-2 gene expression by siRNA transfection in- hibits the protective effect of fluvastatin against cell apoptosis in human aortic endothelial cells

Objective To study the protective effect of fluvastatin,one of the HMG-CoA reductase inhibitors (statins),against oxygen radical-induced oxidative damages in human aortic endothelial cell,and the role of Bcl-2 in this protection.Methods Human aortic endothelial cells with or without Bcl-2 siRNA transfection were subjected to 1-100 nM of fluvastatin and 100 la hydrogen peroxide for 24 hours.Bcl-2 mRNA and protein expression were measured by Taqman quantitative PCR and Western blotting.Cell apoptosis was measured by normal and fluorescent microscopy and Cell Death Detection ELISA.Results In the Bcl-2-expressed cells,fluvastatin significantly reversed hydrogen peroxide-induced microscopic apoptosis and apoptotic DNA fragmentation,which were accompanied by a markedly upregulation of Bcl-2 expression by fluvastatin.However,the endothelial protection by fluvastatin was completely lost in Bcl-2 siRNA transfected cells.Conclusion Fluvastatin protects human endothelial cells against oxygen radical-induced cell apoptosis in vitro,and this protection seemed to be mediated in a Bcl-2 dependent pathway.(J Geriatr Cardil 12008;5:33-38)

Correlation between expression of gastrin, somatostatin and cell apoptosis regulation gene bcl-2/bax in large intestine carcinoma

AIM: To explore the correlation between expression of somatostatin (SS), gastrin (GAS) and cell apoptosis regulation gene bcl-2/bax in large intestine carcinoma.METHODS: Sixty-two large intestine cancer tissue samples were randomly and retrospectively selected from patients with large intestine carcinoma. Immunohistochemical staining for bcl-2, bax, GAS, SS was performed according to the standard streptavidin-biotin-peroxidase (S-P) method.According to the semi-quantitative integral evaluation, SS and GAS were divided into three groups as follows. Scores1-3 were defined as the low expression group, 4-8 as the intermediate expression group, 9-16 as the high expression group. Bax and bcl-2 protein expressions in different GAS and SS expression groups of large intestine carcinoma were assessed.RESULTS: The positive expression rate of bax had a prominent difference between SS and GAS high, intermediate and low expression groups (P＜0.05, x2ss = 9.246; P＜0.05,x2GAS = 6.981). The positive expression rate of bax in SS high (80.0%, 8/10) and intermediate (76.5%, 13/17)expression groups was higher than that in low expression group (40.0%, 14/35) (P＜0.05, x2high vs low = 5.242; P＜0.05,x2middle vs low = 6.097). The positive expression rate of bax in GAS high expression group (27.3%, 3/8) was lower than that in low expression group (69.4%, 25/36) (P＜0.05,x2 = 4.594). However, bax expression in GAS intermediate expression group (46.7%, 7/15) was lower than that in low expression group, but not statistically significant. The positive expression rate of bcl-2 had a prominent difference between SS and GAS high, intermediate and low expression groups (P＜0.05, x2ss = 7.178; P＜0.05, x2GAS = 13.831). The positive expression rate of bcl-2 in GAS high (90.9%, 10/11)and intermediate (86.7%, 13/15) expression groups was higher than that in low expression group (44.4%, 16/36)(P＜0.05,x2high vs low = 5.600; P＜0.05, x2 middle vs low = 7.695).However, the positive expression rate of bcl-2 in SS high (40.0%, 4/10) and intermediate (47.1%, 8/9) expression groups was lower than that in low expression group (77.1%, 27/35)(P＜0.05, x2 high vs low = 4.710; P＜0.05, x2 middle vs low = 4.706).There was a significant positive correlation between the integral ratio of GAS to SS and the integral of bcl-2 (P＜0.01,r=0.340). However, there was a negative correlation between the integral ratio of GAS to the SS and bax the integral of (P＜0.05, r = -0.299).CONCLUSION: The regulation and control of gastrin,somatostatin in cell apoptosis of large intestine carcinoma may be directly related to the abnormal expression of bcl-2, bax.

Effects of Bcl-2 Gene Interference on the Apoptosis,Proliferation and Progesterone Secretion of Goose Follicular Granulosa Cells

Based on published sequences for chicken Bcl-2,three siRNAs（small interfering RNA）were designed,and expression vectors were constructed and transfected into goose granulosa cells cultured in vitro.Bcl-2 protein,apoptosis and proliferation of granulosa cells,48 h after the transf ection,were analyzed by flow cytometry,and progesterone（P）secreted into the culture medium was measured by radioimmunoassay.In addition,apoptosis and Bcl-2 protein level were assessed in untreated granulosa cells from the four largest preovulatory follicles（F1F4）,the smallest preovulatory follicles（SPF）,small yellow follicles（SYF）and atretic follicles.The highest level of Bcl-2 protein was observed in granulosa cells from SPF,and levels in cells from healthy follicles were significantly higher than those of atretic follicles（P【0.05）.Bcl-2 protein levels in cells subjected to RNAi were significantly lower than those of controls（P【0.05）,while apoptosis indices（AI）,proliferation indices（PI）and P secretion in the RNAi treatments were higher than those of controls（P【0.05）.

Study on the Regulation of Bcl-2 Gene on Rat Spermatogenic Cells Apoptosis in Transcription Level

Objective To detect the change of Bcl 2 gene expression in the apopototic process of spermatogenic cells in rat with vasoligation and vasostomy, and to find out the relationship between the transcription of Bcl 2 and the apoptosis of spermatognic cells Materials & Methods Sixty adult male Sprague Dawley rats in 3 groups were operated with vasoligation and vasostomy. Then hybridization in situ with hypersensitive Bcl 2 RNA probe was used to detect the change of Bcl 2 mRNA. Results The transcription of Bcl 2 gene in spermatogenic cells was obviously inhibited in the vasoligation group compared with that in the control group (P<0.05), and the transcription in the vasostomy group showed no difference from that of the control group. Conclusion Bcl 2 gene has an anti apoptotic effect in rats with vasostomy, and there was a transcriptional regulation of Bcl 2 gene in rat spermatogenic cell during the period of pre vasoligation to post vasoligation and to post vasosotomy.

Hepatocellular carcinoma HepG2 cell apoptosis and caspase-8 and Bcl-2 expression induced by injectable seed extract of Coix lacryma-jobi

BACKGROUND:Many Chinese herbs,especially herbal injections,have been shown to have anti-tumor effects in recent years.However,since most reports focus on the clinical effectiveness of these herbs,their mechanisms of action are not well understood.In this study,we assessed apoptosis in the hepatocellular carcinoma (HCC) cell line HepG2 induced by an injectable extract from the seed of Coix lacryma-jobi (Semen coicis,SC),and monitored the expression of Bcl-2 and caspase-8.METHODS:Injectable SC was applied to HepG2 cells at different concentrations and the cells were collected 12,24 and 48 hours later.5-fluorouracil was used as a positive control group,and fluorescence-activated cell-sorting cytometry was used to measure the apoptosis rate of HepG2 cells and the expression of Bcl-2 and caspase-8 proteins.RESULTS:SC induced apoptosis in HepG2 cells in a concentration and time-dependent manner,and the expression of caspase-8 was elevated and prolonged.However,it did not significantly influence the expression of Bcl-2.CONCLUSION:Injectable SC may induce apoptosis in HCC cells by regulating the expression of caspase-8.

8-hydroxy-2-(di-n-propylamino)tetralin intervenes with neural cell apoptosis following diffuse axonal injury

Previous studies have reported a neuroprotective effect of 8-hydroxy-2-（di-n-propylamino）tetralin （8-OH-DPAT） against traumatic brain injury. In accordance with the Marmarou method, rat models of diffuse axonal injury were established. 8-OH-DPAT was intraperitoneally injected into model rats. 8-OH-DPAT treated rats maintained at constant temperature served as normal temperature controls TUNEL results revealed that neural cell swelling, brain tissue necrosis and cell apoptosis occurred around the injured tissue. Moreover, the number of Bax-, Bcl-2- and caspase-3-positive cells increased at 6 hours after diffuse axonal injury, and peaked at 24 hours. However, brain injury was attenuated, the number of apoptotic cells reduced, Bax and caspase-3 expression decreased, and Bcl-2 expression increased at 6, 12, 24, 72 and 168 hours after diffuse axonal injury in normal temperature control and in 8-OH-DPAT-intervention rats. The difference was most significant at 24 hours. All indices in 8-OH-DPAT-intervention rats were better than those in the constant temperature group. These results suggest that 8-OH-DPAT inhibits Bax and caspase-3 expression, increases Bcl-2 expression, and reduces neural cell apoptosis, resulting in neuroprotection against diffuse axonal injury. This effect is associated with a decrease in brain temperature.

SUMO-1 Enhancing the p53-induced HepG2 Cell Apoptosis

In order to investigate the effect of small ubiquitin-like modifier-1 (SUMO-1) on the p53-induced HepG2 cell apoptosis, HepG2 cells were transfected by recombinant plasmids as pwtp53, pMDM2 and pSUMO-1 respectively. Western blot was employed to detect the protein expression of the transfected recombinant plasmids and the rate of apoptosis was measured by flow cytometry. The results showed that in cells transfected with pwtp53 and pwtp53+pSUMO-1, the apoptosis rate was (16.79±1.62) % and (18.15±1.36) % respectively, while transfected with pwtp53+pMDM2, the rate was decreased to (5.17±1.23) %. The apoptosis rate was (14.06±1.84) % in the cells transfected with pwtp53+pMDM2+pSUMO-1, significantly higher than that in the cells Transfected with pwtp53+pMDM2 (P<0.01). The apoptosis rates in the cells were all less than 2 % and had no significant difference among the groups. It was suggested that in the HepG2 cells, SUMO-1 can increase the apoptosis induced by wild-type p53 through binding to p53 protein, post-translational modification and inhibiting the p53 degradation by MDM2.

Expression of bcl-2 gene increases in apoptosis of vascular endothelial cells induced by rattlesnake venom

Apoptosis of vascular endothelial cells (VEC) has been induced by deprivation of survival factors (aFGF and serum) and by rattlesnake venom. The expression of bcl-2 gene has been examined by Northern blotting in the two apoptosis inducing systems. Our results show that the expression of bcl-2 has not been detected in normal culture cells and in apoptotic cells induced by deprivation of survival factors. But in apoptotic cells induced by rattlesnake venom (10 μg/mL), the expression of bcl-2 increases, and its mRNA exhibits two bands. The data first suggest that increasing expression and splitting of bcl-2 mRNA may play an important role in apoptosis of VEC induced by rattlesnake venom, and this finding is helpful to understanding the role of bcl-2 in regulation of apoptosis.

Effects of Low Dose Radiation on Tumor Apoptosis, Cell Cycle and Apoptosis-Related Protein Bcl-2 in Tumor-Bearing Mice

To study the effects of low dose radiation (LDR) on tumor apoptosis, cellcycle progression and changes of apoptosis-related protein Bcl-2 in tumor-bearing mice. Methods:Male mice of Kunming strain were implanted subcutaneously with S180 sarcoma cells in the left inguenas an in situ experimental animal model. Seven days later, the mice were subjected to 75 mGywhole-body γ-irradiation. At 24 and 48 h after the irradiation, all mice were sacrificed. The tumorsizes were measured, and tumor cell apoptosis and cell cycle progression were analyzed by flowcytometry. The expression of apoptosis-related protein Bcl-2 and the apoptotic rate of tumor cellswere observed by immunohistochemistry and electron microscopy. Results: Tumors grew significantlyslower after LDR (P 【 0.05). The tumor cells were arrested in G1 phrase and the expression of Bcl-2protein decreased at 24 h. Apoptotic rate of tumor cells was increased significantly at 48 h afterLDR (P 【 0.01). Conclusion: LDR could cause a G1-phase arrest and increase the apoptosis of tumorcells through the low level of apoptosis-related protein bcl-2 in the tumor-bearing mice. Theorganized immune function and anti-tumor ability are markedly increased after LDR. Our studyprovides practical evidence of clinical application to cancer treatment.

Apoptosis Induced by Bcl-2 Antisense Peptide Acid in HL60 Cells

Objective To study the differences and similarities of the antisense drugs with different structures on the biological functions of HL60 cells. Methods Cytotoxic effects were measured by cell viability assay. The expression levels of protein were assayed by immunofluorescence using fluoresce isothiocyanate label. The morphological changes in apoptotic cells were observed. Flow cytometric analysis of DNA fragmentation was also performed. Results Antisense peptide nucleic acid (PNA) targeting the coding region of the Bcl-2 mRNA could effectively inhibit the growth of HL60 cells, down-regulate the synthesis of Bcl-2 protein and induce apoptosis. After HL60 cells were treated with 10 μmol/L Bcl-2 antisense PNA or antisense oligonucleotide for 72 h respectively, apoptotic rates of HL60 cells were 17.80±1.53 and 13.17±1.12, respectively( P <0.05). Conclusion Antisense PNA targeting the coding region of Bcl-2 mRNA may have stronger antisense effects than the antisense oligonucleotides and could induce apoptosis of HL60 cells.

Expression of Bcl-2 inhibited Fas-mediated apoptosis in human hepatocellular carcinoma BEL-7404 cells

Apoptosis plays an important role in embryonic development, tissue remodeling, immune regulation and tumor regression. Two groups of molecules (Bcl-2 family and "Death factor" family) are involved in regulating apoptosis. In order to know about the effect of Bcl-2 on apoptosis induced by Fas, a typical member of "Death factor" family, the transfection experiments with expression vectors pcDNA3-fl and pcDNA3-bcl-2 were performed in BEL-7404 cells, a human hepatocellular carcinoma cell line which expresses endogenous Fas, but not FasL and Bcl-2. The data showed that the expression of FasL in pcDNA3-fl transfected hepatoma cells obviously induced the apoptosis of the cells. However, the overexpression of Bcl-2 in pcDNA3-bcl-2 transfected 7404/b-16 cells counteracted pcDNA3-fl transient transfection mediated apoptosis. Further study by cotransfection experiments indicated that Bid but not Bax (both were pro-apoptotic proteins of Bcl-2 family) blocked the inhibitory effect of Bcl-2 on Fas-mediated apoptosis. These results suggested that Fas-mediated apoptosis in human hepatoma cells is possibly regulated by Bcl-2 family proteins via mitochondria pathway.

Gambogic acid induces mitochondria-dependent apoptosis by modulation of Bcl-2 and Bax in mantle cell lymphoma JeKo-1 cells

Objective： To study the mechanisms in gambogic acid （GA） -induced JeKo-1 human Mantle Cell Lymphoma cell apoptosis in vitro. Methods： The proliferation of GA-treated JeKo-1 cells was measured by CCK-8 assay and Ki-67 immunocytochemical detection. Apopt0sis, cell cycle and mitochondrial membrane potential were measured by flow cytometric analysis. Caspase-3, -8 and -9 were detected by colorimetric assay. Bcl-2 and Bax were analyzed by Western blotting. Results： GA inhibited cell growth in a time- and dose- dependent manner. GA induces apoptosis in JeKo- 1 cells but not in normal bone marrow cells, which was involved in reducing the membrane potential of mitochondria, activating caspases-3, -8 and -9 and decreasing the ratio of Bd-2 and Bax without cell cycle arresting. Conclusions： GA induced apoptosis in human MCL JeKo-1 cells by regulating Bcl-2/Bax and activating caspase-3, -8 and -9 via mitochondrial pathway without affecting cell cycle.

Simvastatin inhibits apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax

BACKGROUND: Many studies have showed that apoptosis of endothelial cells plays a curial role in the progress of sepsis. But the role of simvastatin in apoptosis of endothelial cells induced by sepsis is not clear. The present study aimed to investigate the role of simvastatin in apoptosis of endothelial cells induced by sepsis and its mechanism.METHODS: Human umbilical vein endothelial cells(HUVECs) were randomly divided into three groups: control group, sepsis serum intervention group(sepsis group) and simvastatin+sepsis serum intervention group(simvastatin group). After 24-hour incubation with corresponding culture medium, the relative growth rate of HUVECS in different groups was detected by MTT assay; the apoptosis of HUVECs was detected by Hoechst33258 assay and fl ow cytometry; and the expression of the Bcl-2 and Bax genes of HUVECs was detected by PCR.RESULTS: Compared with the sepsis group, HUVECs in the simvastatin group had a higher relative growth rate. Apoptotic HUVECs decreased significantly in the simvastatin group in comparison with the sepsis group. Expression of the Bcl-2 gene in HUVECs decreased obviously, but the expression of the Bax gene increased obviously after 24-hour incubation with sepsis serum; however, the expression of the Bcl-2 and Bax genes was just the opposite in the simvastatin group.CONCLUSIONS: Our study suggests that simvastatin can inhibit apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax. It may be one of the mechanisms for simvastatin to treat sepsis.

Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM: To investigate the signaling pathways implicated in phosphatidylethanolamine (PE)-induced apoptosis of human hepatoma HepG2 cells. METHODS: Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle, apoptosis and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE. RESULTS: PE inhibited the growth of HepG2 cells in a doseand timedependent manner. It did notaffect the cell cycle, but induced apoptosis. PE significantly decreased ΔΨm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a doseand time-dependent manner. CONCLUSION: Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.

Growth arrest-specific gene 2 suppresses hepatocarcinogenesis by intervention of cell cycle and p53-dependent apoptosis

BACKGROUND Growth arrest-specific gene 2(GAS2)plays a role in modulating in reversible growth arrest cell cycle,apoptosis,and cell survival.GAS2 protein is universally expressed in most normal tissues,particularly in the liver,but is depleted in some tumor tissues.However,the functional mechanisms of GAS2 in hepatocellular carcinoma(HCC)are not fully defined.AIM To investigate the function and mechanism of GAS2 in HCC.METHODS GAS2 expression in clinic liver and HCC specimens was analyzed by real-time PCR and western blotting.Cell proliferation was analyzed by counting,MTS,and colony formation assays.Cell cycle analysis was performed by flow cytometry.Cell apoptosis was investigated by Annexin V apoptosis assay and western blotting.RESULTS GAS2 protein expression was lower in HCC than in normal tissues.Overexpression of GAS2 inhibited the proliferation of HCC cells with wide-type p53,while knockdown of GAS2 promoted the proliferation of hepatocytes(P<0.05).Furthermore,GAS2 overexpression impeded the G1-to-S cell cycle transition and arrested more G1 cells,particularly the elevation of sub G1(P<0.01).Apoptosis induced by GAS2 was dependent on p53,which was increased by etoposide addition.The expression of p53 and apoptosis markers was further enhanced when GAS2 was upregulated,but became diminished upon downregulation of GAS2.In the clinic specimen,GAS2 was downregulated in more than 60%of HCCs.The average fold changes of GAS2 expression in tumor tissues were significantly lower than those in paired non-tumor tissues(P<0.05).CONCLUSION GAS2 plays a vital role in HCC cell proliferation and apoptosis,possibly by regulating the cell cycle and p53-dependent apoptosis pathway.

Bcl-2 over-expression and activation of protein kinase C suppress the Trail-induced apoptosis in Jurkat T cells

Trail, a tumor necrosis factor-related apoptosis-inducing ligand, is a novel potent endogenous activator of the cell death pathway through the activation of cell surface death receptors Trail-R1 and Trail-R2. Its role, like FasL in activation-induced cell death (AICD), has been demonstrated in immune system. However the mechanism of Trail induced apoptosis remains unclear. In this report, the recombinant Trail protein was expressed and purified. The apoptosis-inducing activity and the regulation mechanism of recombinant Trail on Jurkat T cells were explored in vitro. Trypan blue exclusion assay demonstrated that the recombinant Trail protein actively killed Jurkat T cells in a dose-dependent manner. Trail-induced apoptosis in Jurkat T cells were remarkably reduced by Bcl-2 over expression in Bcl-2 gene transfected cells. Treatment with PMA (phorbol 12-myristate 13-acetate), a PKC activator, suppressed Trail-induced apoptosis in Jurkat T cells. The inhibition of apoptosis by PMA was abolished by pretreatment with Bis, a PKC inhibitor. Taken together, it was suggested that Bcl-2 over-expression and PMA activated PKC actively down-regulated the Trail-mediated apoptosis in Jurkat T cell.

The Relationship of Expression of bcl-2, p53, and Proliferating Cell Nuclear Antigen (PCNA) to Cell Proliferation and Apoptosis in Renal Cell Carcinoma

To investigate the relationship of bcl-2, p53, proliferating cell nuclear antigen (PCNA) to cell proliferation, apoptosis and pathological parameters, the patterns of cell growth and turnover in renal cell carcinoma (RCC), formalin-fixed and paraffin-embedded tissue blocks from 34 patients with RCC were examined. Cell proliferation activity was detected by PCNA immunostaining and the proliferation index (PI) was expressed as a percentage of the PCNA-positive cells in the tumor cells. Apoptosis was detected by terminal deoxy- nucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and the apoptotic index (AI) was expressed as a percentage of the TUNEL-positive cells in the tumor cells. Expressions of bcl-2 and p53 were assessed immunohistochemically. Our results showed that the PI ranged from 6.0 % to 24.0 % (median 12.3 %) and the AI from 2.0 % to 8.0 % (median 5.4 %) in RCC. The expression of the bcl-2 protein was demonstrated in 15 cases (44.1 %); the expression of the p53 protein, however, was seen in only 3 case. bcl-2 positivity was not associated with PI or AI or any pathological parameters. There were close associations between PI and tumor grade and stage, and a significant relationship between AI and the tumor grade of RCC. Our study suggests that bcl-2 positivity was not associated with PI or AI or any pathological parameters. There are close associations between PI and AI and tumor grade and stage of RCC. Active cell proliferation may be accompanied by frequent apoptosis in RCC.

Combined transfection of Bcl-2 siRNA and miR-15a oligonucleotides enhanced methotrexate-induced apoptosis in Raji cells

Objective: B-cell lymphoma 2 (Bcl-2) is an important member of the Bcl-2 family of proteins that regulate the induction of apoptosis. This study aims to investigate whether Bcl-2 small interfering RNA (siRNA) combined with miR-15a oligonucleotides (ODN) could enhance methotrexate (MTX)-induced apoptosis in Raji cells. Methods: Chemically synthesized miR-15a ODN and Bcl-2 siRNA were transfected in Raji cells by using a HiPerFect Transfection Reagent and then combined with MTX. Expression levels of Bcl-2 protein were detected by Western blot. Cell proliferation was determined by CCK8 assay. The rate of cell apoptosis was determined by Annexin V/PI double staining. The morphology of apoptotic cells was observed by Hoechst-33 258 staining. Results: After the cells were transfected with miR-15a ODN combined with Bcl-2 siRNA, Bcl-2 protein levels were evidently decreased. CCK8 assay showed that cell proliferation was significantly decreased and was significantly lower in miR-15a ODN combined with Bcl-2 siRNA plus MTX group than in miR-15a ODN with methotrexate group, Bcl- 2 siRNA with MTX group, and single MTX group (P<0.05). Hoechst 33258 staining revealed numerous apoptotic cells. AnnexinV/PI double staining showed that the apoptotic rates were (13.13±1.60)%, (34.47±2.96)%, (32.87±3.48)%, and (45.47±2.16)% in MTX, Bcl-2 siRNA plus MTX, miR-15a ODN plus MTX, and miR-15a ODN combined with Bcl- 2 siRNA plus MTX groups, respectively. Among these groups, the apoptotic rate of miR-15a ODN combined with Bcl-2 siRNA plus MTX group was the highest; this apoptotic rate was also significantly different from that of miR-15a ODN or Bcl-2 siRNA plus MTX (P<0.05). Conclusions: Bcl-2 siRNA combined with miR-15a ODN could enhance MTX-induced apoptosis in Raji cells. Bcl-2 siRNA and miR-15a combined with MTX may be a useful approach to improve the treatment effects on lymphoma.

Adenosine triphosphate-sensitive potassium channel opener protects PC12 cells against hypoxia-induced apoptosis through PI3K/Akt and Bcl-2 signaling pathways

Although previous studies have shown the neuroprotective effects of the adenosine triphosphate （ATP）-sensitive potassium （KATP） channel opener against ischemic neuronal damage, little is known about the mechanisms involved. Phosphatidylinositol-3 kinase （PI3K）/v-akt murine thy-moma viral oncogene homolog （Akt） and Bcl-2 are thought to be important factors that mediate neuroprotection. The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis, as well as mRNA and protein expression of Akt and Bcl-2. Results demon-strated that pretreatment of PC12 cells with pinacidil, a KATP opener, resulted in decreased PC12 cell apoptosis following hypoxia, as detected by Annexin-V fluorescein isothiocyanate/ propidium iodide double staining flow cytometry. In addition, mRNA and protein expression of phosphorylated Akt （p-Akt） and Bcl-2 increased, as detected by immunofluorescence, Western blot analysis, and reverse-transcription polymerase chain reaction. The protective effect of this preconditioning was attenuated by glipizide, a selective KATP blocker. These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway, which further activates expression of the downstream Bcl-2 gene.

Small hairpin RNA against Bcl-2 increases MTX-induced apoptosis in Raji cells

Objective:The aim of this study was to study the effect of Bcl-2 small hairpin RNA(shRNA) enhancing methotrexate(MTX)-induced apoptosis of Raji cells.Methods:Expression plasmid with Bcl-2 shRNA was transfected into Raji cells by Lipofectmine 2000 and then treated with MTX.At 48 h of transfection,the expression level of Bcl-2 mRNA and protein was evaluated by RT-PCR and immunofluorescence.MTT assay was used to analyze cell proliferation at 24,48 and 72 h.Apoptosis was detected by Giemsa staining and flow cytometric cell cycle analysis.Results:After transfection with Bcl-2 shRNA,the expression levels of Bcl-2 mRNA and protein in Raji cells decreased(P < 0.05).Using Giemsa staining,cells transfected with Bcl-2 shRNA combined with MTX at 48 h displayed changes of apoptosis.MTX significantly inhibited the growth of cells after transfected with Bcl-2 shRNA(P < 0.05).Apoptotic rates of the Raji cells treated with Bcl-2 shRNA combined with MTX significantly increased(P < 0.05),compared with either control shRNA/MTX combination or MTX-treatment cells alone.Conclusion:Our results suggest the shRNA against Bcl-2 mRNA could increase MTX-induced apoptosis of Raji cells.