家蚕凋亡蛋白抑制因子(BmIAP)基因真核表达与功能分析

【目的】家蚕Bombyx mori凋亡蛋白抑制因子(BmIAP)是在家蚕中发现的一个凋亡蛋白抑制因子(IAP)。本研究旨在验证家蚕BmIAP蛋白在家蚕细胞内的功能特征,以进一步研究BmIAP在家蚕细胞凋亡中的作用。【方法】对构建的瞬时表达载体PIZ/V5-BmIAP-dsRed,应用脂质体转染家蚕Bm N-SWU1细胞;应用实时荧光定量PCR和Western blot分析BmIAP mRNA及蛋白表达水平;通过150 ng/m L放线菌素D诱导家蚕Bm N-SWU1细胞12,18和24 h,应用免疫荧光及实时荧光定量PCR方法,分析BmIAP瞬时表达与细胞凋亡的关系。【结果】构建的瞬时表达载体PIZ/V5-BmIAP-dsRed能在家蚕Bm N-SWU1细胞表达BmIAP蛋白,其BmIAP mRNA表达水平上调近45倍,融合蛋白约为60 k D;BmIAP基因瞬时表达72 h后,BmIAP能显著抑制放线菌素D诱导12 h时的家蚕Bm N-SWU1细胞凋亡。【结论】BmIAP蛋白在家蚕细胞中能抑制家蚕细胞凋亡,是家蚕的一种凋亡蛋白抑制因子。     

单纯疱疹病毒2型潜伏相关转录体ORF1的表达及其抗凋亡作用

旨在研究单纯疱疹病毒2型潜伏相关转录体 (LAT) 开放读码框1 (ORF1) 对放线菌素D诱导的凋亡作用的影响。以HSV-2 333基因组为模板PCR扩增ORF1片段,构建重组质粒pEGFP-ORF1,转染Vero细胞,RT-PCR鉴定ORF1的表达。放线菌素D诱导Vero细胞凋亡,通过荧光显微镜观察凋亡小体,Hochest33258荧光染色观察细胞形态变化,MTT检测细胞活性,流式细胞术检测细胞凋亡率。双酶切和测序确认pEGFP-ORF1构建成功,RT-PCR表明该真核表达载体能在Vero细胞中高效表达。转染了pEGFP-ORF1的Vero细胞经放线菌素D凋亡诱导后,Hochest33258染色显示细胞形态正常。MTT结果表明转染了重组质粒pEGFP-ORF1的Vero细胞经放线菌素D凋亡诱导后Vero细胞活性与未经任何处理的正常对照组相比,无显著差异 (P＞0.05),但高于放线菌素D诱导凋亡的Vero细胞组及与转染空质粒pEGFP-C2且放线菌素D诱导凋亡的Vero细胞组,差异具有统计学意义 (P＜0.05)。流式结果表明,转染重组质粒pEGFP-ORF1且经放线菌素D诱导凋亡组与正常对照组凋亡率差异不显著 (P＞0.05),而显著低于放线菌素D诱导凋亡组和转染空质粒pEGFP-C2且经放线菌素D诱导凋亡组 (P＜0.05)。HSV-2 LAT ORF1具有抗放线菌素D诱导的Vero细胞的凋亡作用。     

雷帕霉素对二种鳞翅目昆虫细胞自噬和凋亡的影响

以2种鳞翅目昆虫细胞为材料,采用雷帕霉素进行处理,初步研究自噬作用与昆虫细胞凋亡的关系。结果表明:雷帕霉素能够提高家蚕细胞系BMN-e细胞的自噬水平,并能诱导BMN-e细胞发生凋亡;自噬抑制剂3-甲基腺嘌呤能抑制雷帕霉素诱导的BMN-e细胞凋亡。相反,雷帕霉素虽能诱导斜纹夜蛾细胞系SL-HP细胞的自噬水平提高,但不能诱导斜纹夜蛾Spodoptera litura(Fabricius)细胞发生凋亡;雷帕霉素的预处理能抑制放线菌素D诱导的斜纹夜蛾细胞系SL-HP细胞发生凋亡;自噬抑制剂3-甲基腺嘌呤对放线菌素D诱导的细胞凋亡没有影响。因此家蚕Bombyx mori细胞自噬水平的提高与细胞凋亡具有正相关性,而斜纹夜蛾细胞自噬水平的提高与细胞凋亡不相关,相反还对细胞凋亡的诱导具有一定的抑制作用。     

细胞色素P450表氧化酶对肿瘤坏死因子诱导的内皮细胞凋亡的影响

目的研究细胞色素P450表氧化酶对肿瘤坏死因子诱导的内皮细胞(bovine aortic endothelial cells, BAECs)凋亡的影响.方法在原代培养的BAECs中,分别转染构建在腺相关病毒载体内的细胞色素P450表氧化酶基因2J2,2C11,F87V两周后,用肿瘤坏死因子(TNF-α)(10ng/ml)和放线菌素D(ActD)(5ng/ml)诱导内皮细胞凋亡,通过细胞形态学和流式细胞计数观察其凋亡变化,同时采用Western blot分析检测Bcl-2和P38和丝裂原激动蛋白激酶ERK的表达水平.结果与对照相比,转染细胞色素P450表氧化酶基因后BAECs 凋亡细胞数减少,Bcl-2表达增加, P38表达减低, ERK的磷酸化水平增加.结论细胞色素P450表氧化酶能明显的抑制肿瘤坏死因子诱导的BAECs凋亡,并可能通过上调Bcl-2、下调P38的表达水平和通过增加ERK的磷酸化水平发挥抗凋亡作用.     

单纯疱疹病毒2型潜伏相关转录体RL1的表达及其抗凋亡作用

单纯疱疹病毒2型潜伏相关转录体(LAT)-RL1对放线菌素D诱导的凋亡作用的研究。构建重组pEGFP-RL1质粒,转染Vero细胞,RT-PCR及荧光鉴定重组质粒的表达。放线菌素D诱导Vero细胞凋亡,通过Hochest33342荧光染色观察细胞形态变化,流式细胞术检测细胞凋亡率,JC-1荧光观察膜电位变化,Caspase 3凋亡蛋白检测。RT-PCR和荧光观察表明该真核表达载体能在Vero细胞中高表达。Hochest33342染色转染了pEGFP-RL1的Vero细胞经放线菌素D凋亡诱导后,细胞形态正常。流式结果表明转染重组质粒pEGFP-RL1且经诱导凋亡组与正常对照组凋亡率无差异,而显著低于诱导凋亡组和转染空质粒pEGFP-C2诱导凋亡组。转染重组质粒pEGPF-RL1的细胞JC-1染色后,红色细胞的比例要远大于绿色细胞的比例,而转染空质粒pEGFP-C2被染成绿色细胞的数量较多。Caspase-3结果表明转染了空质粒pEGFP-C2的Vero细胞经诱导凋亡后,活性显著高于转染了pEGFP-RL1经放线菌素D诱导凋亡后的Vero细胞和正常Vero细胞。HSV-2 LAT RL1具有抗放线菌素D诱导的Vero细胞的凋亡作用。     

重组人凋亡素2 配体对放射线诱导肺腺癌A549 细胞凋亡作用的研究

目的:研究凋亡素2配体(Apo-2 ligand,Apo-2L),或称肿瘤坏死因子相关凋亡诱导配体(TNF-related apoptosis-inducing lig-and,TRAIL)在体外对人肺腺癌A549细胞系的放射增敏作用的研究。方法:MTT法检测Apo-2L单药或与放射线联合对腺癌A549细胞的抑制率,将细胞分为4组,对照组、Apo-2L组、Apo-2L+放射照射组、单纯照射组,200ng/ml、286 ng/ml的Apo-2L作用24小时后给予放射照射,照射剂量分别为:(1Gy、1.4 Gy、1.8Gy、2 Gy、3 Gy),然后进行流式细胞仪分析照射后24h各组细胞凋亡率变化。结果:MTT结果显示,腺癌A549细胞的抑制率与Apo-2L的浓度成正相关,凋亡素2配体作用24h后IC50为286ng/ml.流式细胞仪分析显示286ng/ml的Apo-2L处理24h后,细胞凋亡率从(6.68)%上升至(50)%,照射后24h Apo-2L+照射组凋亡率明显升高,为72.790%,对照组0.1185%,Apo-2L组50%,单纯照射组51.5067%。结论:Apo-2L在体外对腺癌A549细胞有抑制增殖和促进凋亡作用,并且Apo-2L联合放射线可以明显提高腺癌A549细胞的凋亡率。     

大豆低聚糖对人胃癌细胞株BGC-823细胞的细胞凋亡和细胞周期的影响

目的通过观察大豆低聚糖对胃癌癌细胞株BGC-823细胞的细胞周期和细胞凋亡的影响,探索乳酸杆菌发酵滤液对胃癌细胞作用的可能机制。方法用光镜和流式细胞仪分析不同浓度大豆低聚糖对BGC-823细胞的凋亡诱导效果;用流式细胞仪分析不同浓度大豆低聚糖对BGC-823细胞细胞周期的影响。结果大豆低聚糖可以诱导BGC-823细胞的凋亡。形态学观察处理后的BGC-823细胞,可见细胞变形,细胞皱缩,体积变小,细胞间隙增大,细胞核固缩。流式细胞仪分析50 mg/ml和100 mg/ml大豆低聚糖作用48 h和72 h BGC-823细胞的凋亡比例,分别为6.76%和7.93%。50 mg/ml大豆低聚糖作用48 h,引起BGC-823细胞G1期阻滞,100 mg/ml大豆低聚糖作用48 h,引起BGC-823细胞出现S期阻滞。结论大豆低聚糖可诱导部分BGC-823细胞凋亡。大豆低聚糖对BGC-823细胞的生长抑制作用在低浓度时可能通过G1期阻滞实现,在高浓度时可能通过S期阻滞实现。     

瘦素对卵巢癌细胞 SKOV3 增殖及凋亡的影响

目的:探讨瘦素对人卵巢癌SKOV3细胞增殖及凋亡的影响及其作用机制。方法:用不同浓度的瘦素(0、50、100、200 ng/m L)处理人卵巢癌SKOV3细胞48 h后,采用MTT法检细胞的生长;以血清饥饿诱导细胞凋亡,同时给予瘦素刺激,Annexin V/PI双染法检测细胞凋亡的变化;western blotting分析p21、cyclin D1、Bcl-2、Bax蛋白的表达水平和ERK1/2通路的活化情况。结果:瘦素以剂量依赖性的方式促进人卵巢癌SKOV3细胞的增殖,同时抑制血清饥饿诱导的细胞凋亡。瘦素处理可下调p21和上调cyclin D1的表达,抑制促凋亡分子Bax的表达和上调抗凋亡分子Bcl-2的表达。瘦素可诱导细胞中ERK1/2通路的活化,其抑制剂PD98059可明显抑制瘦素诱导的促细胞增殖和抗凋亡作用,同时伴随有cyclin D1、Bcl-2蛋白表达的下调和Bax的上调。结论:瘦素可能通过活化ERK1/2通路调节细胞有丝分裂进程,进而促进卵巢癌细胞的增殖;同时通过调节凋亡相关蛋白Bcl-2和Bax的表达抑制卵巢癌细胞的凋亡。     

家蚕微孢子虫感染对家蚕BmN细胞凋亡以及凋亡蛋白抑制因子IAPs表达的影响

【目的】在无任何外界凋亡因素诱导条件下,探究家蚕微孢子虫感染对家蚕卵巢细胞-BmN凋亡的影响,以及凋亡蛋白抑制因子IAPs实相表达的变化情况。【方法】显微镜下观察家蚕微孢子虫感染BmN细胞后不同时间段宿主细胞的变化情况,以及利用荧光定量PCR方法检测家蚕促凋亡基因——细胞色素C(BmCyt c)表达水平的变化,随后检索家蚕基因组与蛋白质家族数据库搜寻家蚕凋亡蛋白抑制因子IAPs基因信息,并通过荧光定量PCR方法对这些基因的实相表达情况进行定量分析。【结果】家蚕微孢子虫感染BmN细胞的前5 d,细胞状态未见明显变化。感染后7 d,BmN细胞的生长受到了一定程度的影响。第12天时,对照组中几乎所有细胞出现空泡化或细胞死亡的现象,而感染家蚕微孢子虫的BmN细胞未见空泡的出现,并且大量细胞形态完整,细胞核清晰可见。同时,BmCyt c基因的表达几乎一直处于被抑制状态,特别是感染后的第10天与第12天,该基因的表达量显著性降低(P0.01)。通过数据库检索共得到4个家蚕凋亡蛋白抑制因子:BmIAP-1、BmIAP-2、BmSurvivin-1与BmSurvivin-2。荧光定量PCR结果表明:BmIAP-1和BmSurvivin-1基因在感染后期(10 d与12 d)表达量有上升趋势,尤其是感染后的12 d,表达量显著上升(P0.01)。然而,BmIAP-2与BmSurvivin-2基因的表达在大多数时间段均处于下调状态。【结论】当无任何外界凋亡因素诱导条件下,家蚕微孢子虫感染BmN细胞后可影响宿主细胞的生长,并可抑制细胞的正常生理凋亡。依据荧光定量PCR结果,我们推测在家蚕微孢子虫感染BmN细胞时,BmIAP-1和BmSurvivin-1蛋白可能在调节细胞凋亡的过程中起一定作用。     

反义寡核苷酸对K562细胞的抑制作用及诱导细胞凋亡的研究

目的研究bcr-abl硫代磷酸反义寡脱氧核糖核酸(Aspo)作用于K562细胞后,对细胞mRNA、蛋白水平的影响,以及诱导细胞凋亡情况。方法Aspo与K562细胞共培养后,用流式细胞仪检测P210蛋白表达及细胞凋亡率,RT-PCR半定量检测bcr-ablmRNA表达情况,电镜观察细胞凋亡的形态学改变。结果K562细胞经浓度大于5μmol/Lbcr-ablAspo处理24h,流式细胞仪检测细胞P210蛋白表达下调甚至完全受抑制,10μmol/Lbcr-ablAspo作用48h,细胞bcr-ablmRNA下降45%左右,当细胞初始浓度为1×104/ml时,Aspo作用120h细胞凋亡率20%～30%,当细胞数增加至1×105/ml时,Aspo作用48h即可使30%细胞发生凋亡,电镜下观察到典型凋亡细胞形态学改变。结论bcr-abl反义核酸对K562细胞mRNA水平具有抑制作用,同时还可诱导细胞凋亡。     

MTS-conjugated-antiactive caspase 3 antibodies inhibit actinomycin D-induced apoptosis

Caspase 3 is critically involved in the pathway of apoptosis. We have conjugated a MTS-transport-peptide to monoclonal and polyclonal anti-caspase-3 antibodies to suppress Actinomycin D-induced apoptosis in human lymphoma T cells. The advantage of using trans-membrane antibodies compared to conventional apoptosis inhibitors is their specific target recognition in the living cell and their lower toxicity compared to conventional apoptosis inhibitors. We could show that a MTS-transport-peptide modified monoclonal anti-caspase-3 antibody reduces Actinomycin D induced apoptosis, as shown by DNA ladder electrophoresis and cell death ELISA. These results indicate that antibodies have a therapeutic potential to inhibit apoptosis in a variety of diseases.     

SfDredd,a Novel Initiator Caspase Possessing Activity on Effector Caspase Substrates in Spodoptera frugiperda

Sf9, a cell line derived from Spodoptera frugiperda, is an ideal model organism for studying insect apoptosis. The first notable study that attempted to identify the apoptotic pathway in Sf9 was performed in 1997 and included the discovery of Sf-caspase-1, an effector caspase of Sf9. However, it was not until 2013 that the first initiator caspase in Sf9, SfDronc, was discovered, and the apoptotic pathway in Sf9 became clearer. In this study, we report another caspase of Sf9, SfDredd. SfDredd is highly similar to insect initiator caspase Dredd homologs. Experimentally, recombinant SfDredd underwent autocleavage and exhibited different efficiencies in cleavage of synthetic caspase substrates. This was attributed to its caspase activity for the predicted active site mutation blocked the above autocleavage and synthetic caspase substrates cleavage activity. SfDredd was capable of not only cleaving Sf-caspase-1 in vitro but also cleaving Sf-caspase-1 and inducing apoptosis when it was co-expressed with Sf-caspase-1 in Sf9 cells. The protein level of SfDredd was increased when Sf9 cells were treated by Actinomycin D, whereas silencing of SfDredd reduced apoptosis and Sf-caspase-1 cleavage induced by Actinomycin D treatment. These results clearly indicate that SfDredd functioned as an apoptotic initiator caspase. Apoptosis induced in Sf9 cells by overexpression of SfDredd alone was not as obvious as that induced by SfDronc alone, and the cleavage sites of Sf-caspase-1 for SfDredd and SfDronc are different. In addition, despite sharing a sequence homology with initiator caspases and possessing weak activity on initiator caspase substrates, SfDredd showed strong activity on effector caspase substrates, making it the only insect caspase reported so far functioning similar to human caspase-2 in this aspect. We believe that the discovery of SfDredd, and its different properties from SfDronc, will improve the understanding of apoptosis pathway in Sf9 cells.     

Establishment and characterization of two embryonic cell lines of <Emphasis Type="Italic">Bombyx mori</Emphasis>

Two cell lines, i.e., BmE-SWU1 and BmE-SWU2, were established from silkworm embryonic tissues of the reversion phase through primary culture in Grace’s medium supplemented with 20% fetal bovine serum. The BmE-SWU1 cell line mainly included diploid spindle cells and round cells, which were large and had severe heteroploidy karyotypes. The population doubling time of the 30th passage of the cell line was 58.7 hr. BmE-SWU2 cells were oblong or round, and small. The population doubling time for the 30th passage of the cell line was 46.6 hr. Of BmE-SWU2 cells 89.9% were diploid (2n = 56). Both strains were attached to epithelial-like cell lines and were susceptible to Bombyx mori nucleopolyhedroviruse (BmNPV). Inter simple sequence repeat (ISSR) fingerprinting of silkworm embryonic cell line was obtained.     

Scattering of the silver-stained proteins of nucleolar organizer regions in Ishikawa cells by actinomycin D.

Scattering of the silver-stained proteins of nucleolar organizer regions (Ag-NOR proteins) was produced by actinomycin D in Ishikawa cells. Scattering of Ag-NOR proteins was found only in cells treated with actinomycin D and various other agents had no effect. Scattering was dose-dependent up to 10(-2) micrograms/ml of actinomycin D, but it was not found at higher concentrations that caused marked inhibition of total DNA and RNA synthesis. Actinomycin D (10(-2) micrograms/ml) caused the following changes: (i) nucleolar segregation and (ii) emergence of dense fibrillar bodies in the nucleoplasm. Ag-NOR proteins were observed on the fibrillar centers and surrounding fibrillar components in control nucleoli, on the fibrillar and amorphous zones in segregated nucleoli, and on the dense fibrillar bodies emerging in the nucleoplasm. The scattering of Ag-NOR proteins was due to the argyrophilic nature of the dense fibrillar bodies. Actinomycin D (10(-1) micrograms/ml) also caused similar morphological alterations in the nucleolus and nucleoplasm, but Ag-NOR proteins were observed only on nucleolar remnants.     

Stiffness changes of tumor HEp2 cells correlates with the inhibition and release of TRAIL-induced apoptosis pathways

Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) is a promising apoptotic agent that can selectively act on tumor cells. However, some cancer cells are resistant to TRAIL mediated apoptosis. In specific type of cells, sensitization by chemotherapeutic drugs may overcome the resistance to TRAIL induced apoptosis. In this work, atomic force microscopy (AFM) nanoindentation spectroscopy combined with fluorescence methods were used to investigate the biomechanical aspects of the resistance and unblocking of apoptosis in larynx carcinoma HEp2 cells treated with TRAIL. It is shown that there is a direct correlation between the increase in mechanical cell stiffness and the inhibition of apoptosis induced by TRAIL in HEp2 cells. Conversely, unblocking of apoptosis by sensitization of HEp2 cells with a chemotherapeutic drug Actinomycin D is related to the depolymerization of F-actin and to the decrease in the cell stiffness. Both effects, that is, changes in the mechanical stiffness of the cell and the inhibition of apoptotic pathway, are closely related to the Bcl-2 activity. Most probably, the depolymerization of F-actin results from downregulation of Rho protein, which in turn is accompanied by a lower activity of Bcl-2 and in consequence releases the intrinsic apoptotic channel. The presented results reveal a promising application of nanoindentation spectroscopy with an AFM tip as a novel tool for monitoring the processes of apoptosis inhibition.     

Infection with Leishmania infantum Inhibits actinomycin D-induced apoptosis of human monocytic cell line U-937

Modulation of host cell apoptosis has been observed in many bacterial, protozoal, and viral infections. The aim of this work was to investigate the effect of viscerotropic Leishmania (L.) infantum infection on actinomycin D-induced apoptosis of the human monocytic cell line U-937. Cells were infected with L. infantum promastigotes or treated with the surface molecule lipophosphoglycan (LPG) or with parasite-free supernatant of Leishmania culture medium and submitted to action of actinomycin D as the apoptosis-inducing agent. Actinomycin D-induced apoptosis in U-937 cells was inhibited in the presence of both viable L. infantum promastigotes and soluble factors contained in Leishmania culture medium or purified LPG. Leishmania infantum affected the survival of U-937 cells via a mechanism involving inhibition of caspase-3 activation. Furthermore, protein kinase C delta (PKC delta) cleavage was increased in actinomycin D-treated U-937 cells and was inhibited by the addition of LPG. Thus, inhibition of the PKC-mediated pathways by LPG can be implicated in the enhanced survival of the parasites. These results support the claim that promastigotes of L. infantum, as well as its surface molecule, LPG, which is in part released in the culture medium, inhibit macrophage apoptosis, thus allowing intracellular parasite survival and replication.     

Eukaryotic translation initiation factor 5A induces apoptosis in colon cancer cells and associates with the nucleus in response to tumour necrosis factor alpha signalling

Eukaryotic translation initiation factor 5A (eIF5A) is thought to function as a nucleocytoplasmic shuttle protein. There are reports of its involvement in cell proliferation, and more recently it has also been implicated in the regulation of apoptosis. In the present study, we examined the effects of eIF5A over-expression on apoptosis and of siRNA-mediated suppression of eIF5A on expression of the tumour suppressor protein, p53. Over-expression of either eIF5A or a mutant of eIF5A incapable of being hypusinated was found to induce apoptosis in colon carcinoma cells. Our results also indicate that eIF5A is required for expression of p53 following the induction of apoptosis by treatment with Actinomycin D. Depiction of eIF5A localization by indirect immunofluorescence has indicated, for the first time, that the protein is rapidly translocated from the cytoplasm to the nucleus by death receptor activation or following treatment with Actinomycin D. These findings collectively indicate that unhypusinated eIF5A may have pro-apoptotic functions and that eIF5A is rapidly translocated to the nucleus following the induction of apoptotic cell death.     

Antizyme1基因转染对K562细胞增殖与凋亡的影响

研究鸟氨酸脱羧酶抗酶蛋白对人红白血病K562细胞增殖、三氧化二砷（ As2O3）诱导凋亡时的影响。方法: 定点突变技术构建缺失frameshift位点的pEGFP-N1-AZ1-mutation重组表达载体。脂质体法转染K562细胞,通过G418筛选获得稳定表达antizyme1的K562pAZ1m细胞系。采用不同浓度的As2O3处理细胞,通过MTT法检测细胞增殖,流式细胞术分析细胞周期及凋亡变化。并通过RT-PCR方法检测antiyme1转染对cyclin D1和survivin基因表达的影响。结果：获得稳定表达antizyme1的K562-AZ1m细胞株后,其增殖能力明显减慢。CyclinD1基因表达降低,细胞主要停滞于G0/G1期。在 As2O3的诱导作用下,细胞凋亡增多,survivin基因表达降低。结论：AZ1基因能够抑制K562细胞增殖,通过对cyclinD1的负调控使细胞周期停滞于G0/G1期。并可能通过下调survivin表达来加强 As2O3对其的诱导凋亡作用     

Cloning of the flap endonuclease-1 gene in Bombyx mori and identification of an antiapoptotic function

The flap endonuclease-1 (FEN-1) gene is involved in DNA replication and repair, and it maintains genomic stability as well as the accuracy of DNA replication under normal growth conditions. However, FEN-1 also plays an important role in apoptosis and cancer development. We cloned the BmFEN-1 gene from Bombyx mori, which was 1343?bp in length and possessed an 1143?bp ORF (123-1266). It consists of seven introns and eight exons that encode a protein with 380 amino acids that has the typical XPG domain. The N-terminal motif is located at amino acids 95-105, and the proliferating cell nuclear antigen interaction motif is located at amino acids 337-344. RNA interference-mediated reduction of BmFEN-1 expression induced cell cycle arrest in S phase in BmE-SWU1?cells. These results suggest that BmFEN-1 can inhibit apoptosis and promote cell proliferation.