自噬抑制增强白藜芦醇对人软骨肉瘤细胞凋亡的诱导

目的:研究白藜芦醇(resveratrol,Res)诱导软骨肉瘤细胞凋亡的同时是否激活自噬及自噬抑制剂联合白藜芦醇对软骨肉瘤细胞的作用。方法:SW1353软骨肉瘤细胞设对照组、Res组、3-甲基腺嘌呤(3-methyladenine,3MA)组及Res+3MA组,用透射电镜观察对照组及Res组细胞自噬体,CCK-8法反映4组细胞活力,Western blotting测cleaved caspase-3、Bax及Bcl-2表达量及TUNEL法来反映4组细胞凋亡情况,Western blotting检测Beclin1、LC3-Ⅱ及p62表达量反映4组细胞自噬情况。结果:在Res作用下,正常细胞活力下降和凋亡水平上升的同时,自噬水平明显上升(P0.05);应用3MA下调正常细胞自噬水平后,3MA组凋亡水平较正常组上升(P0.05);在Res联合3MA作用下,Res+3MA组较Res组细胞活力和细胞自噬水平显著下降(P0.05),而凋亡水平显著上升(P0.05)。结论:Res诱导软骨肉瘤细胞凋亡的同时,上调细胞自噬水平;自噬抑制增强Res对人软骨肉瘤细胞凋亡的诱导。     

黄芩素诱导乳腺癌细胞自噬

目的:考察黄芩素诱导乳腺癌细胞的自噬作用,并初步探讨其机制。方法:采用MTT实验考察黄芩素对乳腺癌MCF-7细胞和4T1细胞活力的影响,确定给药剂量。Western blot检测黄芩素(25、50和100μmol/L)及联合自噬抑制剂3-MA作用下,MCF-7细胞和4T1细胞中自噬特征蛋白LC3-Ⅱ和LC3-Ⅰ的表达水平,流式细胞术Annexin V/PI双染法观察3-MA对黄芩素诱导MCF-7细胞和4T1细胞凋亡的影响,确认黄芩素诱导自噬的作用。通过Western blot考察自噬信号通路相关蛋白p-mTOR、mTOR、p-AKT和AKT的蛋白水平,结合AKT-mTOR激活剂EGF明确AKT-mTOR通路在黄芩素诱导乳腺癌自噬中的作用。结果:50μmol/L及其以上剂量的黄芩素可显著抑制乳腺癌MCF-7细胞和4T1细胞的活力,其作用具有显著的时效和量效性。Western blot结果表明,50和100μmol/L黄芩素作用下MCF-7细胞和4T1细胞的LC3-Ⅱ/LC3-Ⅰ比例显著增强,3-MA加入后又明显降低。流式细胞术结果显示,相比黄芩素单用组,联合自噬抑制剂可促进MCF-7细胞的坏死和凋亡。通路蛋白研究表明mTOR和AKT总量不变,其活化蛋白水平在黄芩素作用下显著降低,而加入EGF后又再次增加。结论:黄芩素可通过抑制AKT-mTOR通路诱导乳腺癌MCF-7细胞和4T1细胞自噬。     

RAD001通过诱导自噬提高人子宫内膜癌细胞对紫杉醇的敏感性

 目的：探讨哺乳动物雷帕霉素靶蛋白(mTOR)抑制剂RAD001通过诱导细胞自噬增强紫杉醇杀伤子宫内膜癌细胞作用的机制。方法：用MTT法检测RAD001对人子宫内膜癌Ishikawa和HEC-1A细胞的生长抑制作用,用激光共聚焦显微镜观察GFP-LC3蛋白的聚集;用流式细胞术检测细胞死亡;用Western blotting方法检测LC3-I、LC3-II、mTOR及ULK1蛋白的表达;用靶向ULK1的siRNA特异性地抑制Ishikawa细胞中ULK1的表达,再检测相关指标。结果：RAD001可抑制Ishikawa和HEC-1A细胞的增殖,提高它们对紫杉醇的敏感性。RAD001诱导Ishikawa和HEC-1A细胞发生自噬及自噬性细胞死亡。RAD001通过抑制mTOR/p70S6K通路、上调ULK1诱导自噬,从而产生紫杉醇增敏作用。结论：RAD001可以通过抑制mTOR信号通路,上调ULK1的表达,诱导自噬性细胞死亡的发生,从而提高子宫内膜癌细胞对紫杉醇的敏感性。     

细胞自噬的调控与自噬程序性死亡的研究进展

自噬(autophagy)是一种溶酶体依赖性降解途径,涉及细胞内长寿蛋白和受损伤细胞器的降解,其既是细胞保守的自我防御机制,又是一种程序性细胞死亡机制(PCD),与机体的多种疾病有密切关系.自噬具有独特的形态改变和特有的调控通路,自噬的调控涉及到多种机制、如翻译后修饰等.凋亡是研究最清楚的程序性细胞死亡机制,凋亡与细胞自噬程序性死亡之间存在着复杂的关系.对哺乳动物细胞自噬的分子调控机制,自噬程序性细胞死亡过程及其与凋亡的关系等方面进行探讨很有意义.     

长春新碱诱导的自噬性细胞凋亡对线粒体膜电位的影响

目的：了解长春新碱（VCR）诱导的自噬性细胞凋亡是否与线粒体跨膜电位（△Ψm）改变有关及其可能的机制。材料与方法：以正常人的肝细胞系为体外模型,应用碘化丙啶（PI）／Rhodamine123(Rh123)双重染色检测△Ψm,通过亚GI期细胞和透射电镜鉴定细胞凋亡。结果与结论：VCR可明显诱导线粒体△Ψm下降,也可以诱导L－02细胞自噬性凋亡。线粒体△Ψm下降可能是VCR诱导自噬性细胞凋亡的关键环节。     

神经干细胞自噬与自噬机制研究现状

<正>自噬(autophagy)作为细胞内物质代谢的重要方式,是亚细胞膜内的结构发生动态变化,也是溶酶体介导细胞内蛋白质和细胞器降解的正常新陈代谢过程。细胞死亡包括坏死、凋亡和自噬三种形式。在细胞平衡合成和分解代谢过程中,通过自噬保持细胞内环境的稳定,使细胞自我更新,保持活力[1-4]。自噬不足则细胞衰老,过度则出现程序性细胞死亡     

TAX1BP1调控B细胞自噬和凋亡的研究

目的 探究TAX1BP1在B细胞自噬与凋亡中的作用。方法 慢病毒感染B淋巴瘤细胞（Raji细胞）,敲低TAX1BP1表达。利用雷帕霉素处理Raji细胞,通过Western blot、细胞免疫荧光染色和流式细胞术,观察自噬流强弱以及细胞凋亡情况。通过检测自噬相关通路P53蛋白表达变化,初步探索调控机制。结果 荧光显微镜观察慢病毒感染阳性率在90%以上。与阴性组比较,shTAX1BP1组细胞中TAX1BP1的m RNA表达水平降低80%、蛋白表达水平降低90%。经10 nmol/L雷帕霉素处理后,与阴性组相比较,shTAX1BP1组LC3II/I比值显著下降（P<0.01）,凋亡相关蛋白Bcl-2表达显著升高,Bax、Caspase-3表达显著下降。敲低TAX1BP1降低Raji细胞自噬水平,减少Raji细胞凋亡。敲低TAX1BP1增加P53蛋白表达,推测TAX1BP1可能通过P53相关通路调控Raji细胞的自噬与凋亡。结论 敲低TAX1BP1可抑制Raji细胞自噬与凋亡,初步预测这一生物学作用可能与P53信号通路有关。本研究为进一步探讨SLE的发病机制奠定了一定的实验基础。     

线粒体自噬对结直肠癌的影响

线粒体是细胞新陈代谢和生长发育过程中重要的细胞器,能够为细胞的生命活动提供能量和底物.当细胞处于恶劣环境时,线粒体通过自噬清除不需要或损伤的线粒体来减轻负荷,补充营养物质,适应恶劣的环境.线粒体自噬对维持细胞生存,抵御环境压力,衰老和凋亡过程起着重要作用.线粒体自噬的异常将导致多种疾病,如:神经退行性变、心脏病、糖尿病以及肿瘤等.随着人们生活习惯的改变,结直肠癌的发病率和死亡率逐年增加,成为中国最常见的恶性肿瘤之一,结直肠癌与线粒体自噬的研究也成为该领域的研究热点.明确线粒体自噬对结直肠癌的作用,有助于进一步了解结直肠癌的发病机制,并为结直肠癌的诊断和治疗提供新的方向和思路.因此,本文将着重阐述线粒体自噬的发生机制及其与结直肠癌的关系.     

脱氧核酶抑制Akt1基因对MCF-7乳腺癌细胞生长的影响

目的 应用脱氧核酶抑制Akt1的表达,观察MCF-7乳腺癌细胞生长及凋亡情况.方法 采用噻唑蓝比色法(MTT)检测脱氧核酶抑制MCF-7乳腺癌细胞增殖作用;DAPI染色法分析细胞凋亡形态学的变化;流式细胞术检测脱氧核酶对MCF-7乳腺癌细胞凋亡的影响;运用蛋白免疫印迹检测分析Akt1、pro-caspase-3、pro...     

Sensitization of MCF-7 breast cancer cells to the apoptotic effect of estradiol

A new substrain of hormone-resistant MCF-7/T breast cancer cells was selected after long-term culturing of estrogen-dependent MCF-7 cells in the presence of tamoxifen. These cells were resistant to the growth-stimulating and cytostatic effects of estradiol and tamoxifen, respectively. MCF-7/T cells gained paradoxical sensitivity to the apoptotic effect of estradiol. Estradiol stimulated p53 expression and decreased DNA-binding activity of NF-κB. Our findings provide indirect evidence that these proteins are involved in the regulation of estrogen-induced apoptosis. These results indicate that tamoxifen-resistant breast cancer cells can be sensitized to the apoptotic effect of estradiol. The data form a basis for the development of new methods of endocrine therapy for breast cancer patients. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 334–337, March, 2006     

SHP-1对人乳腺癌MCF-7细胞侵袭的影响及机制初步探讨

目的探讨SHP-1对人乳腺癌细胞株MCF-7侵袭能力的影响。方法 MCF-7细胞株分别瞬时转染SHP-1的特异性siRNA干扰序列;然后分别通过RT-PCR和Western-blot检测MCF-7细胞干扰前后SHP-1基因和蛋白表达变化,并通过RT-PCR检测干扰前后MMP-9基因变化;通过Transwell小室实验检测干扰SHP-1对细胞侵袭能力的影响。结果 RT-PCR和Western-blot证实SHP-1在人乳腺癌细胞株MCF-7中有表达以及SHP-1SiRNA的干扰效率;干扰SHP-1后,MMP-9的表达量上调;Transwell小室实验证实,与MCF-7阴性干扰对照及空白对照细胞相比,siRNA组的侵袭能力显著增强（P〈0.001）。结论乳腺癌MCF-7中SHP-1的表达水平高低和该细胞侵袭能力高低呈负相关,其侵袭可能和MMP-9的表达呈正相关。     

钙激活中性蛋白酶介导雌激素增强MCF-7乳腺癌细胞的存活力

目的 探讨雌激素(E2)对MCF-7乳腺癌细胞钙激活中性蛋白酶1(CANP-1)基因表达和CANP蛋白酶活性的影响、以及CANP活性在E2增强细胞存活力中的作用.方法 以MCF-7乳腺癌细胞为研究模型、采用RT-PCR法检测mRNA表达、蛋白印迹法观察CANP特异性底物FAK蛋白剪切、血清饥饿诱导细胞死亡、锥虫蓝染色及细胞计数法检测细胞存活力.结果 E2(10 nmoL/L)可明显刺激乳腺癌细胞CANP-1基因表达上调,CANP抑制剂则可显著抑制E2诱导CANP-1基因上调;在无血清培养条件下,E2激活CANP活性及增加细胞存活力(14.3±4.9％,P＜0.05),而CANP抑制剂可显著抑制E2诱导CANP激活以及细胞存活力增强(19.2±3.9％,P＜0.05).结论 E2刺激MCF-7乳腺癌细胞CANP-1基因表达上调并增强CANP活性,后者可能参与介导血清饥饿时E2增强MCF-7细胞的存活力.     

小干扰RNA抑制RUNX2对人乳腺癌MCF-7细胞增殖、凋亡与侵袭的影响

目的探讨小干扰RNA抑制人RUNT相关转录因子2(RUNX2)对人乳腺癌MCF-7细胞增殖、凋亡与侵袭的影响。方法应用化学合成小干扰RNA技术沉默人乳腺癌MCF-7细胞中RUNX2基因的表达,用逆转录-聚合酶链反应(RT-PCR)和Western blot实验验证基因沉默效率。应用MTT方法检测细胞增殖能力变化,流式细胞仪检测细胞凋亡的变化,Transwell实验检测细胞侵袭能力变化。结果设计的siRNA能够明显抑制人乳腺癌MCF-7细胞RUNX2的表达。RUNX2基因沉默后,人乳腺癌MCF-7细胞的增殖能力降低,细胞凋亡率明显提高,侵袭能力显著降低(P<0.01)。结论RUNX2基因是治疗人乳腺癌MCF-7细胞的潜在靶点。     

组蛋白去乙酰化酶抑制剂TSA诱导人乳腺癌细胞凋亡及自噬

目的 探讨组蛋白去乙酰化酶抑制剂曲古霉素(TSA)对人乳腺癌细胞凋亡及自噬的作用及其可能的分子机制。方法采用MTT法检测T47D细胞的增殖能力;流式细胞术检测细胞凋亡的变化;Western blot法检测凋亡及自噬相关蛋白的表达。结果 TSA对人乳腺癌细胞T47D具有增殖抑制作用(P0.05);TSA诱导T47D细胞发生凋亡,下调BCL-2/Bax比值,上调Caspase-3的表达(P0.05);同时自噬相关蛋白LC3B及Beclin-1的表达也明显增加(P0.05,P0.01)。结论 TSA体外能抑制乳腺癌细胞的增殖,其机制与诱导细胞凋亡和自噬作用有关。     

Sonic Hedgehog stimulates migration of MCF-7 breast cancer cells through Rac1

As one of the most common tumors in women, breast cancer has drawn considerable interest from investigators and clinicians in recent years. Despite early diagnosis and best therapeutic regimens available, the prognosis of malignant or metastatic breast cancer patients is still not optimistic. Hedgehog signaling, a classical pathway indispensable to embryonic development, participates in the growth of a variety of tumors. In the present study, the effect of Sonic Hedgehog (Shh) on breast cancer cells was investigated. We identified that Shh signal stimulated the migration of MCF-7 breast cancer cells. Smo and Gli1 were involved in Shh-stimulated migration of MCF-7 cells. Activating Smo and Gli1 induced cell migration, which was blocked by their specific antagonists. The effect of Shh signaling on MCF-7 cells was independent of Wnt5a, Dvl2 and Rab35, but directly dependent on Rac1. In conclusion, our study suggested that Shh promotes breast cancer cell migration via Rac1 independently of the non-canonical Wnt signaling pathway, which may represent a rational molecular target for combination medication in breast cancer.     

CIK细胞对乳腺癌细胞株ZK-75-1的杀伤作用及其机制

目的研究多种细胞因子诱导的杀伤细胞(cyto-kine-inducedkillingcells,CIK)对乳腺癌细胞株ZK-75-1的杀伤作用,并探讨其作用机制。方法通过HE染色观察凋亡细胞ZK-75-1的形态学改变。应用TUNEL(TdT-mediateddUTPnickendlabeling)法检测CIK细胞的凋亡。通过免疫细胞化学染色法检测ZK-75-1细胞中p53、p16、C-myc、Bcl-2及Bax的表达率。结果HE染色显示,CIK细胞向ZK-75-1细胞靠近,形成典型的玫瑰花环状;肿瘤细胞的胞浆中出现颗粒状物,有的肿瘤细胞只见颗粒状碎片;而作为对照的乳腺癌细胞生长良好。TUNEL法检测显示,对照组细胞未染色或染呈均匀的淡蓝色;实验组凋亡的细胞缩小,核或核周染呈深蓝色。CIK细胞作用4~12hZK-75-1细胞的凋亡率上升,作用12~24h细胞的凋亡率下降,与对照组相比较有统计学意义(P<0.01)。免疫细胞化学染色的结果表明,CIK细胞实验组p53、p16、C-myc及Bcl-2蛋白随作用时间的延长均下降,Bax蛋白的表达上调,与对照组相比较均有统计学意义(P<0.01)。结论CIK细胞对乳腺癌细胞ZK-75-1杀伤作用的机制之一,可能与p53、p16、C-myc、Bcl-2蛋白表达的下调及Bax蛋白表达的上调有关,并与CIK细胞作用的时间关系密切。     

Aromatase inhibitor treatment of breast cancer cells increases the expression of let-7f, a microRNA targeting CYP19A1

Aromatase inhibitors (AIs) are considered the gold standard of endocrine therapy for oestrogen receptor-positive postmenopausal breast cancer patients. AI treatment was reported to result in marked alterations of genetic profiles in cancer tissues but its detailed molecular mechanisms have not been elucidated. Therefore, we profiled miRNA expression before and after treatment with letrozole in MCF-7 co-cultured with primary breast cancer stromal cells. Letrozole significantly altered the expression profiles of cancer miRNAs in vitro. Among the elevated miRNAs following letrozole treatment, computational analysis identified let-7f, a tumour-suppressor miRNA which targeted the aromatase gene (CYP19A1) expression. Quantitative real-time PCR assay using MCF-7 and SK-BR-3 cells as well as clinical specimens of a neoadjuvant study demonstrated a significant inverse correlation between aromatase mRNA and let-7f expression. In addition, high let-7f expression was significantly correlated with low aromatase protein levels evaluated by both immunohistochemistry and the western blotting method in breast cancer cases. Results of 3'UTR luciferase assay also demonstrated the actual let-7f binding sites in CYP19A1, indicating that let-7f directly targets the aromatase gene. Subsequent WST-8 and migration assays performed in let-7f-transfected MCF-7 and SK-BR-3 cells revealed a significant decrement of their proliferation and migration. These findings all demonstrated that let-7f, a tumour suppressor miRNA in breast cancer, directly targeted the aromatase gene and was restored by AI treatment. Therefore, AIs may exert tumour-suppressing effects upon breast cancer cells by suppressing aromatase gene expression via restoration of let-7f.     

Effects of bisphenol compounds on the growth and epithelial mesenchymal transition of MCF-7 CV human breast cancer cells

Bisphenol-A (BPA) has been considered as an endocrine disrupting chemical (EDC) because it can exert estrogenic properties. For bisphenol-S (BPS) and bisphenol-F (BPF) that are BPA analogs and substitutes, their risk to estrogendependent cancer has been reported rarely compared with the numerous cases of BPA. In this study, we examined whether BPA, BPS, and BPF can lead to the proliferation, migration, and epithelial mesenchymal transition (EMT) of MCF-7 clonal variant (MCF-7 CV) breast cancer cells expressing estrogen receptors (ERs). In a cell viability assay, BPA, BPS, and BPF significantly increased proliferation of MCF-7 CV cells compared to control (DMSO) as did 17β-estradiol (E2). In Western blotting assay, BPA, BPS, and BPF enhanced the protein expression of cell cycle progression genes such as cyclin D1 and E1. In addition, MCF-7 CV cells lost cell to cell contacts and acquired fibroblast-like morphology by the treatment of BPA, BPS, or BPF for 24 hours. In cell migration assay, BPA, BPS, and BPF accelerated the migration capability of MCF-7 CV cells as did E2. In relation with the EMT process, BPA, BPS, and BPF increased the protein expression of N-cadherin, while they decreased the protein expression of Ecadherin. When BPA, BPS, and BPF were co-treated with ICI 182,780, an ER antagonist, proliferation effects were reversed, the expression of cyclin D1 and cyclin E1 was downregulated, and the altered cell migration and expression of N-cadherin and E-cadherin by BPA, BPS, and BPF were restored to the control level. Thus, these results imply that BPS and BPF also have the risk of breast cancer progression as much as BPA in the induction of proliferation and migration of MCF-7 CV cells by regulating the protein expression of cell cycle-related genes and EMT markers via the ER-dependent pathway.     

Normal breast stem cells, malignant breast stem cells, and the perinatal origin of breast cancer

Both experimental and epidemiological evidence support the concept that the in utero environment can influence an individual's risk of breast cancer in adult life. Recently identified breast stem cells may be the key to understanding the mechanism underlying this phenomenon. It has been theorized that breast cancers arise from breast stem cells. Our emerging view of the characteristics of normal breast stem cells and their link to malignant breast stem cells is reviewed here. It has also been postulated that factors that expand the normal breast stem cell pool in utero would increase the probability that one such cell might undergo an oncogenic mutation or epigenetic change. We dicuss how a number of proposed perinatal determinants of adult breast cancer risk, including (1) in utero estrogen and IGF-1 levels, (2) birthweight, (3) breast density, and (4) early-life mutagen exposure, can be tied together by this “breast stem cell burden” hypothesis.