Hedgehog信号通路抑制剂GANT61对急性髓系白血病细胞增殖和凋亡的影响

目的:探讨以Gli为靶点的hedgehog信号通路抑制剂GANT61对人急性早幼粒细胞白血病细胞HL-60增殖和凋亡的作用及机制。方法:采用CCK-8法观察不同浓度GANT61对HL-60细胞生长增殖的影响;Annexin V-FITC/PI双染检测GANT61对HL-60细胞凋亡的影响;RT-PCR检测48 h时HL-60细胞中gli1、bcl-2、bcl-xl mRNA表达;免疫荧光检测48 h时HL-60细胞中Gli1蛋白表达。结果:GANT61呈时间和浓度依赖性抑制HL-60细胞增殖;GANT61呈浓度和时间依赖性诱导HL-60细胞凋亡;GANT61呈浓度依赖性抑制gli1、bcl-2、bcl-xl mRNA表达;GANT61呈浓度依赖性抑制Gli1蛋白表达。结论:GANT61通过抑制Hedgehog-gli信号通路进而下调bcl-2和bcl-xl基因的表达,对人急性髓系白血病细胞HL-60起抑制增殖,并诱导其凋亡作用。     

Effect of inhibition of extracellular signal-regulated kinase 1 and 2 pathway on apoptosis and bcl-2 expression in Helicobacter pylori-infected AGS cells

Helicobacter pylori induces activation of mitogen-activated protein kinases (MAPKs). However, its effect on H. pylori-induced apoptosis has not been evaluated. Thus, we examined whether H. pylori-induced extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38 MAPK activation affects gastric epithelial cell apoptosis and bcl-2 family gene expression, especially in relation to the cagA status of an H. pylori strain. In flow cytometric and oligonucleosome-bound DNA enzyme-linked immunosorbent assay analyses, infection with cagA(+) H. pylori strains induced gastric cancer cell apoptosis in AGS cells more prominently than infection with cagA mutants. Activation of ERK1/2 and p38 MAPKs was also more prominent in cagA(+) strains. Pretreatment with a MEK inhibitor (PD98059) inhibited ERK1/2 activation and increased H. pylori-induced apoptosis significantly. This increased apoptosis was accompanied by decreased antiapoptotic bcl-2 mRNA expression among bcl-2-related genes (bcl-2, bax, bak, mcl-1, and bcl-X(L/S)), and the effect was also more prominent in the cagA(+) strains. However, the alteration of bcl-2 gene expression was not accompanied by protein level changes. Inhibition of p38 using specific inhibitor SB203580 decreased H. pylori-induced apoptosis but resulted in little alteration of bcl-2-related gene expression. In conclusion, H. pylori-induced ERK1/2 activation, especially by the cagA(+) H. pylori strain, may play a protective role against gastric epithelial cell apoptosis partially through maintenance of bcl-2 gene expression.     

BCL-2 family proteins in peripheral T-cell lymphomas: correlation with tumour apoptosis and proliferation

The present study investigated expression levels of the anti-apoptotic proteins BCL-2, BCL-XL and MCL-1 and the pro-apoptotic proteins BAX and BCL-XS in a series of 112 peripheral T-cell lymphomas (PTCLs) classified according to the WHO classification. Using immunohistochemical methods and a 10% cut-off, each protein was detected in a subset of PTCLs: BCL-2 in 46%, BCL-XS in 49%, BAX in 57%, BCL-XL in 57%, and MCL-1 in 65%. The mean percentage of positive cells for these proteins varied significantly among the PTCL types. Only two types of PTCL, ALK-positive anaplastic large cell lymphoma (ALCL) and enteropathy-type T-cell lymphoma, had a distinctive pattern of expression; all were BCL-2-negative and MCL-1-positive. The mean percentage of BAX-positive and BCL-XS-positive tumour cells was higher in ALK-positive ALCL than in ALK-negative ALCL or other types of PTCL (p = 0.06 and p = 0.01, respectively, Kruskal-Wallis test). MCL-1 was detected significantly more frequently (p = 0.01, chi-square test) and at higher levels (p = 0.0001, Kruskal-Wallis test) in ALK-positive ALCL and ALK-negative ALCL than in other PTCL types. The apoptotic rate, evaluated by the TUNEL assay, correlated inversely with BCL-2 expression (p = 0.035). The proliferation index, assessed by the MIB-1 antibody, correlated with expression levels of MCL-1 (R = 0.42, p = 0.003), BCL-2 (R = 0.32, p = 0.027), BAX (R = 0.33, p = 0.014), and BCL-XL (R = 0.34, p = 0.015) (Spearman rank). In conclusion, BCL-2 family proteins are expressed by a subset of PTCLs and their levels correlate with some histological types, apoptotic rate, and proliferation index. Expression of these proteins may explain the poor response of many types of PTCL to standard chemotherapy. These proteins may also provide novel targets for experimental therapy.     

细胞色素C对HL-60细胞促凋亡作用及其对bcl-2、bcl-xl基因表达的影响

目的：探讨细胞色素C在体外作用于HL-60细胞时细胞发生的变化及其相关凋亡基因bcl-2、bcl-xl表达变化的机制。方法:用不同浓度的细胞色素C作用于HL-60细胞24 h，然后用MTT检测细胞色素C对HL-60细胞抑制率；用普通光镜、荧光显微镜检测HL-60细胞形态的变化；用流式细胞仪、DNA凝胶电泳对HL-60细胞凋亡的检测；用RT-PCR检测bcl-2、bcl-xl mRNA表达的变化。结果:细胞抑制率随着细胞色素C浓度的增加而增加；当细胞色素C浓度在0-37.5 mg/L作用HL-60细胞24 h，随着细胞色素C浓度的增加，HL-60细胞发生的凋亡逐渐增加，可见典型的凋亡细胞和明显的DNA梯度条带；同时，在该浓度范围内，bcl-2、bcl-xl mRNA表达逐渐减少；当细胞色素C浓度大于37.5 mg/L时，细胞凋亡率并不增加，而是下降，但是坏死细胞明显增加。结论：一定浓度细胞色素C能诱导HL-60细胞发生凋亡，并且细胞凋亡率、bcl-2、bcl-xl基因表达的变化与细胞色素C浓度呈一定的量效依赖关系，细胞色素C诱导HL-60细胞凋亡可能与抑制bcl-2、bcl-xl基因的表达有一定的关系。     

重组人CD40配体对卵巢癌SKOV3细胞生长特性的影响

目的： 观察重组人CD40配体（rhCD40L）对卵巢癌细胞株SKOV3增殖、表面抗原变化、细胞周期、凋亡相关基因及肿瘤坏死因子受体相关因子( TRAFs)的影响。 方法： 在体外将SKOV3细胞与不同浓度的rhCD40L作用72 h后MTT法测定细胞增殖；直接免疫荧光标记流式细胞术测定细胞表面抗原及TRAFs变化，RT-PCR法测定凋亡相关基因c-myc、bcl-2、bcl-xl的表达程度，并用Annexin V和PI双标记测定细胞凋亡水平。 结果： rhCD40L在100 μg/L的低剂量时即可抑制SKOV3细胞增殖（0.65±0.10 vs 0.81±0.05），其作用随着rhCD40L浓度的增加而加强，10 mg/L时抑制率达（0.13±0.12 vs 0.83±0.15，P＜0.01），呈明显的浓度相关性，并使细胞分裂阻滞于G1期；rhCD40L可上调SKOV3细胞CD95的表达（42.4% vs 59.2%, P＜0.05），下调抗凋亡基因bcl-2和bcl-xl的表达，促进其凋亡；SKOV3细胞高表达TRAF2（81.3%±9.2%）、TRAF5（47.2%±7.2%）和TRAF6（44.5%±6.3%），rhCD40L可显着下调TRAF2（50.4%±5.3%，P＜0.05）、TRAF5（7.2%±2.1%，P＜0.01）和TRAF6（5.1%±1.1%，P＜0.01）表达，而上调TRAF3（25.2%±6.2% vs 68.8%±5.3%，P＜0.01）表达，对TRAF1（4.3%±1.2% vs 5.1%±1.4%）和4（7.4%±1.2% vs 8.1%±1.4%）的表达则无作用。 结论： rhCD40L通过下调bcl-2和bcl-xl基因表达，并改变细胞内TRAFs表达，使SKOV3细胞的增殖受阻滞于G1期，并促进其凋亡。     

Poliovirus modulates Bcl-xl expression in the human U937 promonocytic cell line

Poliovirus induces bcl-2-independent apoptosis in the human U937 promonocytic cell line [28]. Here we describe that this cell death, induced after viral infection, correlates with the modulation of the protooncoprotein Bcl-xl. Furthermore, poliovirus infection decreases the detected Bcl-xl in a U937 clone that overexpresses this protein (U937bcl-xl). Although in U937bcl-xl cells, Bcl-xl was not as highly regulated as in parental U937 cells, correlation between Bcl-xl modulation and the cleavage of poly(ADP-ribose)polymerase could be observed. Nevertheless, the induction of shutoff after infection of transfected control U937neo or U937bcl-xl clones was not significantly altered. Finally, production of new viral particles was slightly restricted in Bcl-xl-overexpressing U937 cells. Taken together, these results suggest that Bcl-xl is modulated during the induction of apoptosis in the promonocytic cell line U937 after poliovirus infection, although modulation of this protooncogene was not sufficient to modify the course of infection.     

Sodium butyrate-induced apoptosis and ultrastructural changes in MCF-7 breast cancer cells

This study investigated the effects of sodium butyrate (NaB) on Michigan Cancer Foundation-7 (MCF-7) breast cancer cells and analyzed the relevant mechanism. Here, we demonstrated that a certain concentration of NaB effectively induced MCF-7 cell apoptosis. Cell counting kit-8 (CCK-8) assay was used to detect cell viability and the apoptosis rate. Western blotting was used to detect changes in the Bcl-2 expression level. We observed cell shape changes with microscopy. Immunofluorescence revealed some apoptotic nuclei. Electron microscopy revealed thick nucleoli, chromatin margination, reduced mitochondria, and dramatic vacuoles. Collectively, our findings elucidated the morphological mechanism by which NaB changed the ultrastructure of MCF-7 cells.     

Methionine aminopeptidase-2 regulates human mesothelioma cell survival: role of Bcl-2 expression and telomerase activity

Methionine aminopeptidase-2 (MetAP2) is the molecular target of the angiogenesis inhibitors, fumagillin and ovalacin. Fumagillin can also inhibit cancer cell proliferation, implying that MetAP2 may play a quite complex role in tumor progression. Here, we examined the expression and function of MetAP2 in an in vitro model of human mesothelioma. We found that mesothelioma cells expressed higher MetAP2 mRNA levels than primary normal mesothelial cells. Consistently, fumagillin induced apoptosis, owing to early mitochondrial damage, in malignant, but not in normal mesothelial cells. Transfection of mesothelioma cells with a MetAP2 anti-sense oligonucleotide determined a time-dependent inhibition of cell survival and induced nucleosome formation. Interestingly, mRNA and protein levels of the anti-apoptotic gene bcl-2 as well as telomerase activity were selectively reduced after MetAP2 inhibition in mesothelioma cells, whereas bcl-2 overexpression counteracted the effect of MetAP2 inhibition on telomerase activity and apoptosis. MetAP2 inhibition also increased caspase activity and the caspase inhibitor, zVAD-fmk, prevented fumagillin-induced apoptosis, but it did not alter telomerase activity. These results indicate that MetAP2 is a main regulator of proliferative and apoptotic pathways in mesothelioma cells and suggest that MetAP2 inhibition may represent a potential target for therapeutic intervention in human mesothelioma.     

Bax/bcl-2: cellular modulator of apoptosis in feline skin and basal cell tumours

Bcl-2 and bax are two members of the BCL-2 gene family that play a prominent role in the regulation of apoptosis. Bax and bcl-2 expression were examined immunohistochemically in normal (healthy) feline skin and in 24 benign feline cutaneous basal cell tumours. The tumours were also examined for cellular proliferation by measurement of reactivity for the proliferation marker Ki-67, and for apoptosis by in-situ labelling for fragmented DNA. Bcl-2 was detected in normal basal epithelium and in 23 of 24 basal cell tumours. Bax was detected in both basal and suprabasal epithelium, but in only seven of 24 tumours. For tumours that expressed both bax and bcl-2, the bax:bcl-2 ratio was low. Neither bax nor bcl-2 expression was detected in 14 feline cutaneous squamous cell carcinomas. Basal cell tumours showed modest cellular proliferation (median, 17.5% Ki-67- reactive cells), but few (less than 1%) apoptotic cells. The slow, indolent growth of feline cutaneous basal cells in these benign skin tumours may be a response, at least in part, to opposing regulatory expressions of bcl-2 and bax. Copyright Harcourt Publishers Ltd.     

Alterations on the 5' noncoding region of the BCL-6 gene are not correlated with BCL-6 protein expression in T cell non-Hodgkin lymphomas.

The BCL-6 proto-oncogene is expressed in germinal center B lymphocytes, in their neoplastic counterparts, and in a subpopulation of germinal center and perifollicular T lymphocytes. Rearrangements and/or mutations of the 5' noncoding region of the bcl-6 gene have been demonstrated in a large majority of diffuse large B cell lymphomas. Some, but not all, of these genetic alterations lead to dysregulation of the protein. Recently, anaplastic large cell lymphomas with T and null cell phenotypes, as well as T lymphoblastic lymphomas, have also been reported to exhibit immunoreactivity to the anti-BCL-6 antibody. We collected 33 T cell non-Hodgkin lymphomas (T-NHLs) and analyzed their expression of the BCL-6 protein by immunohistochemistry and investigated the organization of the bcl-6 gene by Southern blot and single strand conformation polymorphism (SSCP). The expression of BCL-6 was demonstrated in 37.5% of lymphoblastic (LBL), 40% of anaplastic large cell (ALCL), and 33% of peripheral T cell lymphomas (PTCL). BCL-6-positive malignant cells exhibited the CD4+ or CD4+/CD8+ phenotype. The bcl-6 gene was in a germline configuration in all T-NHLs examined, and a mutation at the first exon-intron boundary region structure of the wild-type bcl-6 gene was detected in 3 of 12 PTCL. One case of PTCL with mutations of the 5' noncoding region expressed BCL-6. In conclusion, expression of the BCL-6 protein is demonstrable independently of bcl-6 alterations in T-NHLs. This further suggests that molecular mechanisms other than rearrangements and/or mutations of the 5' noncoding region of the bcl-6 gene can result in expression of the protein. Whether these lymphomas arose from T cells expressing BCL-6 or expressed BCL-6 as part of the malignant transformation process needs to be determined. Finally, structural alterations of bcl-6 are rare in T-NHLs, but mutations do occur in the 5' noncoding region. We suggest that expression of BCL-6 in T cells may facilitate lymphomagenesis by repressing critical cytokines and cell cycle regulators.     

胶质瘤bcd—2基因表达水平与其细胞增殖和凋亡关系的研究

目的 探讨胶质瘤细胞ｂｃｌ－２基因表达水平与肿瘤恶性程度、细胞增殖活性及凋亡程度的关系。方法 以６９例不同级别的人胶质瘤组织为研究对象,用原位杂交及免疫组化染色ＡＢＣ法分别检测ｂｃｌ－２ｍＲＮＡ、ｂｃｌ－２蛋白和增殖细胞核抗原（细胞增殖活性标记物）的表达,并用３’末标记法做原位细胞凋亡检测。结果 ６４例（９２．８％）表达ｂｃｌ－２ｍＲＮＡ,６０例（８７．０％）表达ｂｃｌ－２蛋白,两者的表达水平呈正     

RNA干扰沉默Bax基因对线粒体途径软骨细胞凋亡的影响

 【摘要】 目的 利用体外培养的鼠软骨细胞,研究RNA干扰沉默Bax基因表达对经线粒体途径细胞凋亡的影响。方法 体外分离培养SD大鼠软骨细胞;Bax siRNA干扰沉默Bax基因表达。RT-PCR和Western blot检测mRNA及蛋白表达水平;MTT法检测细胞活力;Annexin V-FITC/PI双标记法检测细胞凋亡率;Western blot检测Bcl-2、Cytochrome C蛋白的表达。结果 Bax siRNA干扰24h后,Bax的mRNA和蛋白的表达水平均明显降低。细胞凋亡受到明显抑制,细胞存活率增高。并且,在Bax基因沉默的细胞中,Cytochrome C蛋白表达水平降低,同时Bcl-2蛋白表达水平升高。结论 RNA干扰沉默Bax基因可抑制鼠软骨细胞凋亡并且促进其存活,其机制可能与线粒体途径相关。     

Expression of bcl2 family proteins and active caspase 3 in classical Hodgkin's lymphomas

The expression of various bcl2 family proteins has been reported in Hodgkin and Reed-Sternberg cells, but the proteins bad, bid, and bim have not been analyzed in classical Hodgkin's lymphomas (HLs). This study aimed to investigate the expression of the proteins bcl2, bcl-xl, mcl1, bax, bak, bad, bid, bim, and active caspase 3, and the TUNEL (terminal deoxynucleotidyl transferase-mediated in situ labeling) index to gain further insight into the apoptosis profile of classical HLs. A high expression of the proteins bcl2, bcl-xl, mcl1, bax, bak, bad, bid, and bim in HRS cells was found in 27 of 101 (27%), 95 of 101 (94%), 27 of 97 (29%), 73 of 95 (77%), 37 of 102 (36%), 85 of 94 (90%), 19 of 109 (17%), and 43 of 91 (47%) cases, respectively. The high expression of bcl-xl, bax, and bad in HRS cells in most classical HLs indicates that these proteins may play predominant roles in the regulation of apoptosis in classical HLs. Active caspase 3-positive and TUNEL-positive Reed-Sternberg cells were detected in 47 of 70 (67%; range, 0%-12%) and 60 of 71 (85%; range, 0%-19%) cases, respectively. Significant positive correlations were found between bax/bcl2 (P = .002), bad/bcl2 (P = .020), bad/bcl-xl (P = .003), and bim/mcl1 (P = .036). Based on these findings, it could be hypothesized that the antiapoptotic proteins bcl2, bcl-xl, and mcl1 may counteract the expression of the proapoptotic proteins bax, bad, and bim, thereby contributing to the survival of Reed-Sternberg cells.     

Overexpression of BCL-2, BCL-X, and BAX in primary central nervous system lymphomas that occur in immunosuppressed patients.

In contrast to primary central nervous system lymphomas (PCNSLs) that occur in immunocompetent patients, most of those that occur in immunosuppressed patients are associated with Epstein-Barr virus (EBV). BCL-2-related proteins either block or promote cell death, forming homo- or heterodimers with each other. LMP-1, EBV latent protein, has been shown to upregulate BCL-2 and BCL-XL. This observation suggests that these proteins may be involved in the transformation process of EBV-infected cells. Twenty-three cases of PCNSLs were studied: 12 of the patients were immunosuppressed, and 11 were immunocompetent. For all cases, we collected clinical information, histologic data, and immunophenotype and tested for the presence of EBV (EBER-1, LMP-1). Apoptosis was assessed by the TdT-mediated dUTP-biotin nick-end labeling method and quantified by image analysis. In three cases, electron microscopy was performed. The BCL-2 family proteins (BCL-2, BCL-X, MCL1, and BAX) and p53 expression were studied by immunohistochemistry on paraffin slides. All cases were classified as diffuse large B-cell lymphomas. PCNSLs in immunosuppressed patients were characterized by EBV association, necrosis, important gliosis, and numerous macrophages. There was no significant difference between the two groups regarding the TdT-mediated dUTP-biotin nick-end labeling staining (P = .08). In contrast, PCNSLs in immunosuppressed patients were shown to express high levels of BCL-2, BCL-X, and BAX in more than 80% of tumor cells in 7, 10, and 11 cases, respectively. In immunocompetent patients, only one case showed a high level of BCL-2 expression in more than 80% of the cells, whereas BCL-X and BAX were overexpressed in two cases. These differences are significant (P < .05). In contrast, there was no significant difference between the two groups in MCL-1 expression. Besides EBV association and necrosis, PCNSLs related to immunosuppression are characterized by an overexpression of BCL-2-related proteins, without dramatically modifying their susceptibility for apoptosis.     

Sodium butyrate-inducible replication of human cytomegalovirus in a human epithelial cell line.

Replication of human cytomegalovirus (HCMV) in a human epithelial thyroid papillary carcinoma cell line (TPC-1) was restricted. However, pretreatment of these cells with 5 mM sodium butyrate (NaB) for 24 hr before infection enhanced both HCMV yield and infectious center titer to a similar level of that seen in human embryonic lung fibroblast cells. Immunofluorescence staining, gel electrophoresis, and Northern blot analysis revealed that TPC-1 cells are nonpermissive for expression of HCMV major immediate early (IE1) functions, but many of the cells become permissive after being treated with NaB. The presence of cycloheximide during NaB pretreatment of the cells efficiently diminished the stimulatory effect of NaB on expression of the IE1 gene. Therefore, it appeared that NaB induces the synthesis of a cellular protein(s) which apparently plays an important role in the conversion of nonpermissive cells to a permissive state for expression of this critical viral gene. Transient chloramphenicol acetyltransferase (CAT) assay experiments indicated that in TPC-1 cells the HCMV-CAT construct which contains the complete IE1 promoter regulatory region was expressed poorly, whereas a high level of CAT activity was detectable in the NaB-treated cells. Therefore, these results suggest that the enhancing effect of NaB on HCMV replication is expressed through some host cellular factor(s), and the HCMV IE1 promoter regulatory region is most likely to be the primary target of NaB action.     

反义bcl-2硫代磷酸寡脱氧核苷酸对小细胞肺癌细胞株NCI-H446的抑制作用及诱导细胞凋亡的研究

目的:观察反义bcl-2硫代磷酸寡脱氧核苷酸(AS-PS-ODN)对小细胞肺癌细胞株NCI-H446mRNA、蛋白以及增殖、活力和凋亡的影响。方法: 合成bcl-2AS-PS-ODN作用于小细胞肺癌细胞株NCI-H446, 半定量RT-PCR检测bcl-2mRNA表达;免疫细胞化学染色和流式细胞仪检测Bcl-2蛋白表达;通过克隆形成率、细胞计数、流式细胞仪DNA倍体分析、TUNEL等指标观察bcl-2 AS-PS-ODN对细胞增殖、活力和凋亡的影响。结果:①bcl-2 AS-PS-ODN能特异性地降低NCI-H446细胞bcl-2mRNA和Bcl-2蛋白的表达。1μmol/LAS-PS-ODN作用24h后bcl-2mRNA表达量下降69.5%, 48h后Bcl-2蛋白下降62.7%。②bcl-2 AS-PS-ODN能够抑制细胞增殖和活力, 诱导细胞凋亡, 1μmol/LAS-PS-ODN作用24h后, 细胞凋亡率约为22.3%-32.7%。结论:bcl-2 AS-PS-ODN能够特异性降低bcl-2mRNA、蛋白表达, 抑制NCI-H446细胞的增殖和活力, 并诱导细胞凋亡。     

Bcl-2 protein expression in developing human brain

Using immunocytochemical methods, the expression of bcl-2 antiapoptotic protein was studied in developing brain of human 5-8-week embryos. It was established that during the period studied several zones of bcl-2-positive cell concentration were present. These included the ventricular zone of the brain vesicles wall, cortical plate, medullary nuclei, vascular plexus primordium (in 5-6-week embryos), IV ventricle roof and vascular plexus of rhombencephalon. In the area of forming leptomeninx, bcl-2 protein was demonstrated in the endothelium of blood vessels. The detection of intensified expression of bcl-2 protein in some cellular populations of developing human brain proves their increased stability against apoptosis and indicates their priority significance in the provision of normal neurohistogenesis.