过表达RSK4m1对人乳腺癌细胞MDA-MB-231生长和侵袭的影响

目的 探讨过表达p90核糖体S6蛋白激酶4变异体1（ribosomal protein S6 kinase 4 variant 1,RSK4m1）对人乳腺癌MDA-MB-231细胞生长和侵袭的影响。方法 通过负载RSK4m1慢病毒在人乳腺癌MDA-MB-231细胞中稳定过表达RSK4m1。以MDA-MB-231亲本细胞为空白对照组（Con组）、转染空载病毒的MDA-MB-231细胞为阴性对照组（Mock组）、转染过表达RSK4m1的MDA-MB-231细胞为实验组（OE组）。采用qRT-PCR和Westen Blot法检测各组RSK4m1 mRNA及蛋白的表达;CCK-8法检测细胞增殖情况;细胞划痕实验检测细胞的迁移能力;Transwell小室侵袭实验检测细胞的侵袭能力。结果 OE组中RSK4m1 mRNA及蛋白的表达量均明显高于Con组及Mock组（P<0.05）。CCK-8实验显示,24 h、48 h、72 h和96 h时OE组细胞增殖均低于Mock组和Con组（P<0.05）;细胞划痕实验显示,细胞培养24 h后,OE组细胞迁移率显著低于Con组和Mock组［（14.53±0.64）% vs （25.67±2.44）%、（24.47±2.25）%,P<0.05］。Transwell小室侵袭实验显示,OE组细胞侵袭能力显著低于Con组和Mock组［（35.00±5.57）个 vs （66.70±5.86）个、（58.67±4.16）个,P<0.05］。结论 过表达RSK4m1可显著抑制人乳腺癌MDA-MB-231细胞增殖、迁移和侵袭能力,为RSK4m1可能成为乳腺癌的治疗新靶点提供了实验依据。     

miR-204对乳腺癌MCF-7细胞增殖及凋亡的影响

目的 探讨miR-204在人乳腺癌组织及MCF-7细胞中的表达水平及其对乳腺癌细胞增殖及凋亡的影响。方法 提取癌症和肿瘤基因组图谱（the cancer genome atlas,TCGA）数据库中浸润性乳腺癌的miR-204相关数据进行汇总,转染miR-204过表达病毒,筛选稳定转染细胞株并通过RT-qPCR检测转染率,MTT法检测过表达miR-204后乳腺癌MCF-7细胞的增殖情况,流式细胞仪检测细胞凋亡情况。 结果 miR-204在浸润性乳腺癌组织中的表达水平较癌旁组织明显下调（P＜0.001）,且与淋巴结转移和远处转移相关（P＜0.05）。过表达miR-204能够抑制乳腺癌MCF-7细胞的增殖能力（P＜0.05）;miR-204上调后,细胞凋亡率达到（34.7±1.9）%,细胞凋亡能力明显增强（P＜0.001）。结论 miR-204可抑制乳腺癌细胞增殖并介导细胞凋亡。     

肿瘤相关成纤维细胞自噬对三阴性乳腺癌细胞转移的影响

目的探讨三阴性乳腺癌(TNBC)细胞和肿瘤相关成纤维细胞(CAFs)共培养环境下,CAFs自噬促进TNBC细胞转移的作用机制。 方法(1)分离和鉴定CAFs：采用前瞻性研究方法收集2015年1月至2016年12月期间,就诊于南方医科大学珠江医院的6例TNBC患者(临床分期Ⅱ～Ⅲ期)的肿瘤组织和癌旁正常组织,从这些标本中分离CAFs和正常成纤维细胞(NFs)。进一步采用荧光抗体标记抗α平滑肌肌动蛋白(α-SMA),并计算α-SMA阳性细胞比例,采用Western blot检测CAFs和NFs的α-SMA表达水平,以鉴定CAFs为本实验所需。(2)评估CAFs自噬水平：利用Western blot检测CAFs组、NFs组和CAFs＋3-MA组(加入自噬抑制剂3-MA的CAFs)自噬标志蛋白beclin 1和p62的表达水平。(3)明确CAFs自噬对MDA-MB-231和BT-549细胞迁移的作用：采用Transwell小室模型观察不同培养条件[分4组,包括空白组(含10% FBS的DMEM培养基,即普通培养基)、NFs组、CAFs组和CAFs＋3-MA组]下MDA-MB-231和BT-549的细胞迁移数。(4)明确CAFs自噬对MDA-MB-231和BT-549细胞发生上皮-间质转化(EMT)的影响：采用Western blot检测3种培养条件[普通培养基(空白组)、CAFs条件培养基(CAFs-CM组)和加入3-MA的CAFs条件培养基(CAFs＋3-MA-CM组)]下MDA-MB-231和BT-549 EMT相关蛋白(E-cadherin,N-cadherin, vimentin)的表达情况。正态分布的数据用±s表示,偏态分布的数据用M(P₂₅-P₇₅)表示。2组间α-SMA表达水平比较采用两独立样本非参数秩和检验,α-SMA阳性细胞比例比较采用两独立样本t检验,各组间细胞自噬标志蛋白表达水平、细胞迁移数和EMT相关蛋白表达水平的比较均采用单因素方差分析。 结果(1)荧光显微镜下观察发现,每视野下CAFs组α-SMA阳性细胞比例显著高于NFs组[(81.11±3.95)%比(5.11±2.37)%,t＝49.49, P<0.001); Western blot检测表明,CAFs组α-SMA表达水平也高于NFs组[M(P₂₅～P₇₅)：0.98(0.95～0.98)比0.48(0.47～0.48),Z＝2.023, P＝0.043]。(2)CAFs组、NFs组和CAFs＋3-MA组细胞beclin 1表达水平分别为0.99±0.03、0.73±0.04和0.26±0.02,p62表达水平分别为0.75±0.02、0.98±0.03和0.97±0.01,组间比较,差异均有统计学意义(F＝546.188、136.353,P均<0.001),其中,CAFs组的beclin 1表达水平显著高于CAFs＋3-MA组(P<0.001),p62表达水平明显低于CAFs＋3-MA组(P<0.001)。(3)CAFs组、NFs组、CAFs＋3-MA组以及空白组MDA-MB-231细胞迁移数分别为(41.67±2.78)、(23.33±2.18)、(22.00±1.76)、(18.00±2.12)个,4组比较,差异有统计学意义(F＝198.374,P<0.001);同样,4组BT-549细胞的迁移数分别为(35.22±1.97)、(22.00±2.60)、(25.11±2.15)、(15.22±2.00)个,组间比较,差异也有统计学意义(F＝129.424,P<0.001),并且,CAFs组的MDA-MB-231和BT-549细胞迁移数均明显高于其余3组(P<0.050)。(4)MDA-MB-231细胞分别与普通培养基(空白组)、CAFs条件培养基(CAFs-CM组)和加入3-MA的CAFs条件培养基(CAFs＋3-MA-CM组)共培养后,3组细胞的E-cadherin表达水平分别为0.79±0.03、0.54±0.02和0.87±0.04, N-cadherin表达水平分别为0.59±0.02、1.00±0.02和0.93±0.02, vimentin表达水平分别为0.62±0.03、1.01±0.01和0.89±0.09,组间比较,差异也均有统计学意义(F＝139.286、604.905、43.884,P均<0.001)。同样,BT-549细胞分别与以上3种培养基共培养后,3组细胞的E-cadherin表达水平分别为1.01±0.03、0.63±0.03和0.98±0.03, N-cadherin表达水平分别为0.58±0.01、0.94±0.04和0.95±0.03, vimentin表达水平分别为0.61±0.01、0.98±0.03和0.75±0.02,组间比较,差异也均有统计学意义(F＝210.102、184.477、217.659,P均<0.001)。 结论CAFs可促进TNBC细胞MDA-MB-231和BT-549的迁移和EMT过程,且该作用与CAFs自噬相关。     

异黏蛋白调控三阴性乳腺癌细胞干性的机制研究

目的研究异黏蛋白(MTDH)对三阴性乳腺癌干性的调控机制,并探讨miR-30a-5p对MTDH的调控作用。 方法(1)回顾性分析2017年5月至2018年9月湖北医药学院附属太和医院手术治疗的37例三阴性乳腺癌患者的肿瘤组织标本及同期非三阴性乳腺癌手术切除标本37例。采用免疫组织化学方法检测所有标本中MTDH的表达。(2)用定量RT-PCR和Western blot检测MCF-10A、MCF-7、MDA-MB-231、MDA-MB-468 4种细胞系中MTDH的mRNA和蛋白表达。(3)为了探讨MTDH对三阴性乳腺癌细胞干性、细胞增殖及Wnt/β-catenin信号通路的影响,用MTDH的siRNA转染三阴性乳腺癌细胞系MDA-MB-231和MDA-MB-468(siMTDH组),无效干扰RNA转染的细胞作为对照组。用Western blot检测MDA-MB-231、MDA-MB-468细胞系中干细胞标志物sox2、Nanog及CD133相对表达量,用细胞克隆实验观察细胞克隆数,用Western blot检测Wnt/β-catenin信号通路蛋白β-catenin、Myc和cyclin D1的表达。(4)荧光素酶报告实验：为评估miR-30a-5p能否靶向调控MTDH,用MTDH的3′-UTR和miRNA-30a-5p合成含有MTDH 3′-UTR野生型和突变型荧光素酶报告质粒,分别转染HepG2细胞,pGL3空载体转染细胞作为空载体组,24 h后观察荧光。三阴性乳腺癌与非三阴性乳腺癌组织中MTDH蛋白表达比较用t检验。4种细胞系中MTDH mRNA及蛋白表达比较用方差分析。对照组与siMTDH组中sox2、Nanog、CD133、β-catenin、Myc、cyclin D1蛋白表达及细胞克隆数比较用t检验。细胞相对荧光比值比较采用方差分析。组间两两比较采用LSD法。 结果(1)三阴性乳腺癌组织中MTDH蛋白相对表达量为2.82±1.37,而非三阴性乳腺癌组织为5.65±2.02,差异有统计学意义(t＝-7.046, P<0.001)。(2)在4种细胞系(MCF-7、MDA-MB-231、MDA-MB-468及MCF-10A)中,MTDH mRNA表达比较,差异有统计学意义(F＝7 155.320, P<0.001)。两两比较结果显示：与正常乳腺细胞(MCF-10A)比较,乳腺癌细胞(MCF-7、MDA-MB-231、MDA-MB-468)中MTDH mRNA表达增加(P均<0.001);与MCF-7比较,MDA-MB-231、MDA-MB-468中的MTDH mRNA表达量更高(P均<0.001);MDA-MB-468中的MTDH mRNA表达低于MDA-MB-231细胞(P<0.001)。4种细胞系中,MTDH蛋白相对表达量比较,差异有统计学意义(F＝90.053, P<0.001)。两两比较结果显示：与正常乳腺细胞比较,乳腺癌细胞(MCF-7、MDA-MB-231、MDA-MB-468)中MTDH蛋白相对表达量增加(P均<0.050);与MCF-7比较,MDA-MB-231、MDA-MB-468中的MTDH蛋白相对表达量更高(P均<0.050);MDA-MB-468中的MTDH蛋白相对表达量低于MDA-MB-231细胞(P<0.050)。(3)在三阴性乳腺癌细胞系MDA-MB-231和MDA-MB-468中,对照组与siMTDH组的干细胞标志物sox2、Nanog及CD133相对表达量比较,差异均有统计学意义(MDA-MB-231：1.19±0.10比0.52±0.05,1.16±0.13比0.34±0.03,1.19±0.06比0.54±0.08,t＝10.304、10.959、11.700,P＝0.001、0.005及P<0.001;MDA-MB-468：1.26±0.05比0.34±0.02,1.19±0.07比0.52±0.04,1.21±0.02比0.37±0.01,t＝31.185、15.584、75.001,P均<0.001);对照组与siMTDH组的细胞克隆数比较,差异均有统计学意义(MDA-MB-231：87.33±9.02比33.33±3.51,t＝9.664,P＝0.001;MDA-MB-468：70.67±4.73比24.33±3.21,t＝14.041,P<0.001);对照组与siMTDH组的Wnt/β-catenin信号通路蛋白β-catenin、Myc及cyclin D1蛋白表达比较,差异均有统计学意义(MDA-MB-231：0.26±0.06比0.08±0.01,0.74±0.03比0.32±0.00,0.72±0.01比0.26±0.04,t＝5.115、21.222、21.690,P均<0.050;MDA-MB-468：0.33±0.03比0.15±0.06,0.56±0.04比0.22±0.02,0.65±0.02比0.31±0.02,t＝4.973、13.969、21.897,P均<0.001)。(4)荧光素酶报告实验结果显示：3组细胞相对荧光比值比较,差异有统计学意义(F＝174.189,P<0.001),空载体组与突变型质粒转染组的相对荧光比值均高于野生型质粒转染组(P均<0.001)。 结论miR-30a-5p可靶向调控MTDH,参与三阴性乳腺癌细胞干性调控,miR-30a-5p/MTDH通路可能是一个新的治疗靶点。     

RSK4与TRAF4在不同乳腺细胞中的表达及分子作用通路研究

目的 研究抑癌基因p90核糖体S6蛋白激酶4（p90 ribosomal protein S6 kinase4,RSK4）相互作用蛋白与肿瘤坏死因子受体相关因子4（tumor necrosis factor receptor associated factor 4 ,TRAF4）在不同乳腺细胞株中的表达,探讨RSK4-TRAF4相互作用蛋白所在分子作用通路对乳腺癌侵袭转移的影响。方法 采用实时荧光定量PCR 法检测 RSK4和TRAF4在 HBL-100正常乳腺细胞株和MCF-7、Her-2阳性型、MDA-MB-231人乳腺癌细胞株中的表达情况。用蛋白质免疫印迹法（Western-blot）检测RSK4和TRAF4以及MAPK通路下游蛋白ERK1/2在HBL-100、MCF-7、Her-2阳性型、MDA-MB-231 4种乳腺细胞株中的表达。结果 RSK4 mRNA 、TRAF4 mRNA 在4种细胞中均表达,RSK4 mRNA在HBL-100表达量最高,在MCF-7、Her-2阳性型、MDA-MB-231 细胞中含量依次降低;TRAF4 mRNA在4种细胞中的表达量由低到高依次为HBL-100、MCF-7、Her-2阳性型、MDA-MB-231 细胞,RSK4 mRNA 、TRAF4 mRNA 在4种细胞中两两比较,差异有统计学意义（P<0.05）。RSK4与TRAF4在4种细胞中蛋白表达水平与mRNA表达水平相一致,具有高度相关性（r_RSK4=0.92,P< 0.01;r_TRAF4=0.82,P< 0.01）;ERK1/2蛋白表达量由高到低依次为MDA-MB-231、Her-2阳性型、MCF-7、HBL-100。在mRNA转录水平,RSK4和TRAF4 表现出负相关（r₁=-0.81,P< 0.01）;在蛋白翻译水平,RSK4和TRAF4 同样呈现出高度负相关（r₂=-0.84,P< 0.01）。结论 RSK4和TRAF4具有较高的负相关性,RSK4与TRAF4相互作用后可能通过MAPKs下游信号通路ERK起分子调控作用。     

乳腺癌肿瘤相关成纤维细胞对MDA-MB-231细胞增殖、凋亡、黏附及侵袭的影响

目的:研究乳腺癌肿瘤相关成纤维细胞(carcinoma-associated fibroblasts,CAFs)对乳腺癌细胞增殖、凋亡、黏附和侵袭能力的影响.方法:首先,从6例乳腺癌病人肿瘤及癌旁正常乳腺组织块分别分离培养成对的CAFs和正常成纤维细胞(normal fibroblasts,NFs).然后,通过Transwell小室将CAFs或NFs与乳腺癌MDA-MB-231细胞体外共培养,进行增殖(MTT)、侵袭、黏附实验及流式细胞仪细胞凋亡检测.结果:MDA-MB-231与CAFs或NFs共培养后乳腺癌细胞的增殖活性显著增强(P＜0.05).与NFs相比,这种差异在同CAFs共培养组更为明显(P =0.011).与CAFs共培养之后,MDA-MB-231的早期凋亡显著减少(P=0.026);而与NFs共培养之后则无显著差异.CAFs或NFs对MDA-MB-231细胞的细胞周期和晚期凋亡无明显影响.与CAFs或NFs共培养24小时后,MDA-MB-231细胞的侵袭、黏附能力明显增强,黏附数目为(34.7±4.84)个/视野(CAFs)和(20.16±0.09)个/视野(NFs),(P =0.000);侵袭数为(89±4.62)个/视野(CAFs)和(81.6±6.08)个/视野(NFs),(P＜0.05).结论:CAFs能促进乳腺癌MDA-MB-231细胞的增殖、减少其早期凋亡;同时对乳腺癌细胞的黏附和侵袭能力有促进作用.可是NFs的作用较CAFs为弱.有关CAFs影响乳腺癌肿瘤细胞的生物学特性的机制有待于进一步研究.     

不同照射剂量对BRCA基因突变及其非突变的乳腺癌细胞DNA损伤和凋亡的影响

目的 探讨不同照射剂量对BRCA基因突变及BRCA基因非突变的乳腺癌细胞DNA损伤和凋亡的影响。方法 BRCA基因突变的乳腺癌细胞株MDA-MB-436及BRCA基因非突变的乳腺癌细胞株MDA-MB-231分别按0 Gy、2 Gy、4 Gy、6 Gy、8 Gy、10 Gy照射剂量进行X射线照射。以流式细胞术仪检测细胞凋亡率,在各照射剂量中,取γH2AX免疫荧光焦点最明显的时间点（30 min）检测细胞DNA双链损伤情况。结果 乳腺癌细胞DNA损伤及细胞凋亡率均随照射剂量增加而加重,8 Gy照射剂量时两个细胞株的DNA损伤及细胞凋亡率均达到最高,MDA-MB-436细胞分别为（47±1.802）个和（21.245±1.325）%,MDA-MB-231细胞分别为（45±1.779）个和（19.220±1.220）%。不同照射剂量下,MDA-MB-436细胞较MDA-MB-231细胞的DNA损伤严重及细胞凋亡率增加,两者比较差异均有统计学意义（P均＜0.05）。两个细胞株8 Gy照射剂量的细胞焦点增长数及细胞凋亡增长率与10 Gy照射剂量比较,差异均无统计学意义（P均＞0.05）。 结论 随着X射线照射剂量由0 Gy至10 Gy不断增强,乳腺癌细胞损伤不断增加,BRCA基因突变的乳腺癌细胞DNA损伤及细胞凋亡率均较BRCA基因非突变的乳腺癌细胞明显增加,具有更高的放射敏感性。     

人乳腺癌组织中miR-34a的表达及其在乳腺癌细胞系中的功能研究

目的 探讨miR-34a在人乳腺癌组织和细胞中的表达情况及对乳腺癌细胞系MDA-MB-231增殖、迁移侵袭和凋亡等生物学行为的影响,为研究乳腺癌组织中miR-34a的作用及深入了解乳腺癌发生发展的分子机制奠定理论基础。方法 通过实时荧光定量PCR（qRT-PCR）法检测miR-34a在20例人乳腺癌组织和癌旁正常组织中表达量的差异并比较其在人乳腺癌细胞系MDA-MB-231、MCF-7和正常乳腺上皮细胞MCF-10A中的表达差异;体外利用脂质体转染技术,转染miR-34a的模拟物（miR-34a mimic）和标记FAM（绿色荧光）的阴性对照(negative control ,miR-NC)进入MDA-MB-231细胞,研究miR-34a对细胞增殖活性、迁移和侵袭能力以及凋亡和周期分布的影响。结果 miR-34a在乳腺癌组织中的表达量较正常癌旁组织下调(P＜0.01);在MDA-MB-231、MCF-7和MCF-10A中的表达呈依次增高的趋势(P＜0.01);转染miR-34a mimic与转染miR-NC的MDA-MB-231相比,其增殖活力、迁移和侵袭能力均下降(P＜0.01),凋亡增加(P＜0.01),细胞周期被阻滞在G1/G0期（P＜0.01）。结论 miR-34a在乳腺癌组织和细胞系MDA-MB-231及MCF-7中的表达较正常组织和MCF-10A中都明显下调;miR-34a能够抑制肿瘤细胞MDA-MB-231的增殖、侵袭迁移,增加细胞凋亡率,使细胞周期阻滞在G0/G1;miR-34a可能起到抑癌作用,其表达水平与乳腺癌的发生发展密切相关。     

RSK4与Ki-67、cyclin D1、CXCR4、E-cadherin在乳腺癌裸鼠移植瘤中的相关性研究

目的 分析乳腺癌裸鼠移植瘤中核糖体 S6蛋白激酶 4（ribosomal protein S6 kinase 4,RSK4） 与Ki-67、cyclin D1、CXCR4、E-cadherin表达的相关性,进一步探讨RSK4在乳腺癌发展中的作用机制。方法 将转染siRNA （RSK4-RNAi-LV）的MCF-7细胞（实验组）、转染siRNA （NC-GFP-LV）的MCF-7细胞（阴性对照组）和未转染的MCF-7细胞（空白对照组）分别接种至裸鼠乳腺脂肪垫下,建立乳腺癌裸鼠移植瘤模型,剥离裸鼠移植瘤;采用免疫组织化学法检测移植瘤标本中增殖因子RSK4、Ki-67、cyclin D1 及侵袭因子CXCR4、E-cadherin蛋白的表达。结果 实验组RSK4、E-cadherin蛋白的表达水平分别为（3.2±0.5）％、（28.2±0.7）％,明显低于空白对照组的（36.7±3.4）％、（51.7±4.2）％和阴性对照组的（61.1±5.1）％、（49.2±3.8）％,差异有统计学意义（F=56.79,61.89,P＜0.05）。实验组Ki-67、cyclin D1、CXCR4蛋白的表达水平分别为（67.8±5.8）％、（61.7±4.6）％、（56.3±3.9）％,明显高于空白对照组的（34.5±1.4）％、（29.7±2.5）％、（30.7±3.1）％和阴性对照组的（29.8±1.9）％、（35.7±4.6）％、（28.5±3.7）％,差异有统计学意义（F=45.24,52.16,61.24,P＜0.05）。相关性分析显示,RSK4与 Ki-67、cyclin D1、CXCR4表达呈负相关（r=-0.857,-0.826,-0.867,P<0.001）,与E-cadherin表达呈正相关（r=0.879,P<0.001）。 结论 RSK4可能通过调节CXCR4、Ki-67、CyclinD1和E-cadherin肿瘤相关因子的表达,在乳腺癌在乳腺癌生长及转移过程中发挥作用。     

酪氨酸激酶抑制剂tyrphostin AG1478对乳腺癌细胞作用的机制探讨

目的:探讨表皮生长因子受体(epithelial growth factor receptor,EGFR)的小分子酪氨酸激酶抑制剂tyrphostin AG1478对乳腺癌细胞的作用机制.方法:以乳腺癌细胞MCF-7(EGFR-/+)和MDA-MB-468(EGFR+++)为研究对象,采用MTT及克隆形成实验检测AG1478对乳腺癌MCF-7和MDA-MB-468细胞增殖和生长效应的影响;Western 印迹法测定EGFR、Akt和丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)的表达及活化水平;进一步应用FCM检测AG1478对MDA-MB-468细胞早期凋亡的影响.结果:AG1478 可抑制MDA-MB-468细胞的增殖和生长(P＜0.05),对MCF-7细胞增殖则无明显的抑制效应(P＞0.05);同时,MDA-MB-468细胞经AG1478处理后,细胞中磷酸化Akt(p-Akt)和磷酸化MAPK(p-MAPK)的表达水平明显降低(P＜0.05);FCM检测结果表明,AG1478可增加MDA-MB-468细胞的早期凋亡水平(P＜0.05).结论:AG1478可下调PI3K/Akt及Ras/Raf/MAPK信号通路,从而抑制乳腺癌MDA-MB-468细胞增殖及生长,并促进细胞凋亡;但其对MCF-7细胞无明显作用.     

乳腺癌干细胞富集与鉴定的初步研究

目的:通过从MCF-7、ZR-75-1、MDA-MB-231乳腺癌细胞系中培养富集及鉴定乳腺癌干细胞(breast cancer stem cell,BCSC),寻找培养与富集乳腺癌干细胞的方法。方法:贴壁培养MCF-7、ZR-75-1、MDA-MB-231细胞系,倒置显微镜观察各细胞形态;流式细胞仪分别分选收集CD44-CD24-、CD44-CD24+、CD44+CD24-及 CD44+CD24+ 细胞,其中CD44+CD24-为乳腺癌干细胞,其余三类为对照组;MTT法计数细胞,绘制MCF-7、ZR-75-1、MDA-MB-231细胞系生长曲线;MCF-7细胞系进行无血清悬浮培养1个周期,流式细胞仪检测分子表面标记物CD44+CD24-含量,贴壁培养的CD44+CD24-乳腺癌干细胞为对照组;将分选的MCF-7（CD44+CD24-）和分选的其余MCF-7细胞（非CD44+CD24-）进行干性成球实验,鉴定CD44+CD24-干性表达。结果:MCF-7、MDA-MB-231细胞系富含表面标志物CD44-CD24-的乳腺癌细胞;ZR-75-1细胞系富含分子表面标志物CD44+CD24+的乳腺癌细胞;生长曲线显示MCF-7、ZR-75-1、MDA-MB-231均呈持续增长,MDA-MB-231细胞生长较MCF-7、ZR-75-1细胞快;通过无血清悬浮培养CD44+CD24-乳腺癌干细胞由19.4%富集到88.9%;成球实验中CD44+CD24-表型细胞成球数量较分选的其余MCF-7细胞（非CD44+CD24-表型）明显增多,成球率分别为（36.5±1.7）%,（1.1±0.5）%。结论:流式细胞仪可成功分选出分子表面标志物为CD44+CD24-的乳腺癌干细胞;CD44+CD24-可能不是乳腺癌干细胞唯一的表面标志物;MDA-MB-231细胞系较MCF-7、ZR-75-1细胞系生长快;无血清悬浮培养法可简便、高效地富集乳腺癌干细胞;CD44+CD24-乳腺癌干细胞干性表达较强。     

Cell signaling by urokinase-type plasminogen activator receptor induces stem cell-like properties in breast cancer cells

Signaling by urokinase-type plasminogen activator receptor (uPAR) can cause epithelial-mesenchymal transition (EMT) in cultured breast cancer cells. In this report, we show that uPAR signaling can also induce cancer stem cell (CSC)-like properties. Ectopic overexpression of uPAR in human MDA-MB-468 breast cancer cells promoted the emergence of a CD24(-)/CD44(+) phenotype, characteristic of CSCs, while increasing the cell surface abundance of integrin subunits β1/CD29 and α6/CD49f that represent putative mammary gland stem cell biomarkers. uPAR overexpression increased mammosphere formation in vitro and tumor formation in an immunocompromized severe combined immunodeficient (SCID) mouse model of orthotopic breast cancer. Hypoxic conditions that are known to induce EMT in MDA-MB-468 cells also increased cell surface β1/CD29, mimicking the effects of uPAR overexpression. Antagonizing uPAR effector signaling pathways reversed the increase in cell surface integrin expression. Whereas uPAR overexpression did not induce EMT in MCF-7 breast cancer cells, CSC-like properties were nevertheless still induced along with an increase in tumor initiation and growth in the orthotopic setting in SCID mice. Notably, in MCF-7 cell mammospheres, which display a well-defined acinus-like structure with polarized expression of E-cadherin and β1-integrin, cell collapse into the central cavity was decreased by uPAR overexpression, suggesting that uPAR signaling may stabilize epithelial morphology. In summary, our findings show that uPAR signaling can induce CSC-like properties in breast cancer cells, either concomitantly with or separately from EMT.     

相关成纤维细胞自噬调控对乳腺癌MCF-7细胞上皮间质转化影响

目的 研究报道,乳腺癌相关成纤维细胞(cancer associated fibroblasts,CAFs)在乳腺癌的侵袭、转移中起到促进作用,而机制未明.本研究探讨乳腺癌CAFs自噬调控对MCF-7细胞EMT进程的影响.方法 采用胶原酶消化法对CAFs及配对人乳腺癌正常成纤维细胞(NBFs)进行原代培养,采用免疫荧光和蛋白质印迹法进行鉴定;建立CAFs和NBFs与MCF-7条件培养基(CM)共培养及Transwell小室共培养模型,共分为3组进行实验,空白组即MCF-7单独培养组(CON),对照组即正常乳腺癌成纤维细胞与MCF-7共培组(NBFs),实验组即乳腺癌相关成纤维细胞与MCF-7共培养组(CAFs).Transwell侵袭及迁移实验检测各组MCF-7细胞侵袭和迁移能力.蛋白印迹法检测各组MCF-7细胞EMT上皮标志分子E-cadherin蛋白和间质标志分子N-cadherin和Vimentin蛋白表达情况;蛋白质印迹法检测CAFs与NBFs自噬相关蛋白LC3B、Beclin1和p62表达差异;自噬抑制剂3MA处理CAFs后蛋白质印迹法检测CAFs上述自噬相关蛋白表达差异;予以自噬抑制剂3MA预处理CAFs后,收集CM与MCF-7共培养,分3组进行实验,空白组即MCF-7单独培养组(CON);对照组即MCF-7与CAFs-CM共培养组(CAFs-CM);实验组即MCF-7与3MA-CAFs-CM共培养组(3MA-CAFs-CM).蛋白质印迹法检测各组MCF-7细胞EMT上皮标志分子E-cadherin蛋白和间质标志分子N-cadherin和Vimentin蛋白表达情况.结果 通过酶消化法原代培养可获取α-SMA(+)、Vimentin(+)E-cadherin(-)具有CAFs典型特征的肌成纤维细胞;Transwell侵袭、迁移实验证实CAFs可促进MCF-7细胞侵袭、迁移;蛋白质印迹法检测显示,CAFs组MCF-7 E-cadherin蛋白表达量为0.432±0.012,比NBFs组的0.585±0.02及空白组的0.659±0.016表达水平低,F=120.098,P<0.05.而CAFs组间质蛋白标志物Vimentin蛋白表达量为0.309±0.065,比NBFs组的0.103±0.011及空白组的0.062±0.009表达低,F=42.395,P均<0.05.CAFs组N-cadherin蛋白表达量为1.439±0.07比BNFs组的1.3347±0.028及空白组的1.176±0.021表达低,F=22.578,P<0.05,提示CAFs促进MCF-7发生EMT;CAFs细胞的Beclin1蛋白表达量为2.950±1.261,高于NBFs的0.862±0.727,t=-3.21,P<0.05;CAFs细胞的LC3BⅡ/LC3BⅠ灰度值比值为2.937±0.194,高于NBFs的2.314±0.224,t=-3.638,P<0.05;而CAFs p62蛋白表达量为0.342±0.093,低于NBFs的0.750±0.021,t=7.432,P<0.05,提示CAFs自噬水平高于NBFs.予以自噬抑制剂3MA处理CAFs后,处理组CAFs细胞的Beclin1蛋白表达量为0.211±0.008,低于未处理组的0.266±0.009,t=8.094,P<0.05;处理组CAFs细胞的LC3BⅡ/LC3BⅠ灰度值比值为0.496±0.004,低于未处理组的0.618±0.022,t=9.312,P<0.05;而处理组的p62蛋白表达量为0.307±0.043,高于未处理组的0.143±0.008,t=-6.471,P<0.05,说明3MA可以抑制CAFs自噬水平.自噬调控后共培养,各组E-cadherin蛋白表达有统计学意义,F=44.157,P<0.05;与对照组MCF-7细胞E-cadherin蛋白表达量1.209±0.010相比,CAFs-CM组的1.062±0.027表达下调,而3MA-CAFs-CM组MCF-7细胞E-cadherin蛋白表达量为1.104±0.019,较CAFs-CM组表达上调,均P<0.05;3组MCF-7细胞Vimentin和N-cadherin表达差异有统计学意义,P<0.05.结论 CAFs能够促进MCF-7发生EMT并增强其侵袭转移能力,而抑制CAFs自噬后,其诱导的MCF-7发生EMT进程受到抑制.     

转铁蛋白修饰多柔比星脂质体靶向抑制乳腺癌细胞增殖的研究

目的：利用转铁蛋白（TF）修饰多柔比星脂质体,并探讨其对乳腺癌细胞增殖的影响。方法采用薄膜超声法制备脂质体,利用硫酸梯度法制备多柔比星脂质体,然后采用后插入法制备 TF修饰多柔比星脂质体。激光共聚焦显微镜检测乳腺癌细胞 MCF-7和 MDA-MB-231对 TF-多柔比星脂质体的摄取,四甲基偶氮唑盐比色法（MTT 法）检测 TF-多柔比星脂质体靶向作用 MCF-7和 MDA-MB-231细胞后的杀伤能力,软琼脂克隆集落实验检测 TF-多柔比星脂质体对 MCF-7和 MDA-MB-231细胞的生长抑制作用。结果激光共聚焦显微镜观察显示,MCF-7细胞和 MDA-MB-231细胞对 TF-多柔比星脂质体摄取率显著高于多柔比星脂质体;MTT 法检测结果则显示,TF-多柔比星脂质体对 MCF-7细胞[（20．8±3．2）μmol／L]和 MDA-MB-231细胞[（20．1±3．0）μmol／L]杀伤的 IC50显著低于多柔比星脂质体[（158．6±24．6）μmol／L;（160．1±25．1）μmol／L）]和游离多柔比星[（161．7±26．2）μmol／L;（166．9±27．0）μmol／L）],差异有统计学意义（F ＝116．03,P ＜0．001;F ＝75．29,P ＜0．001）。软琼脂克隆集落实验显示,TF-多柔比星脂质体对克隆集落的生长抑制显著优于多柔比星脂质体、游离多柔比星及对照组[MDA-MB-231细胞直径：（60．5±10．4）μm、（94．3±16．8）μm、（131．8±22．6）μm、（162．8±30．3）μm;MCF-7细胞直径：（31．8±5．5）μm、（62．1±11．1）μm、（108．6±18．6）μm、（157．4±29．3）μm],差异有统计学意义（F ＝87．17,P ＜0．0001;F ＝178．23,P ＜0．0001）。结论 TF-多柔比星脂质体对乳腺癌细胞体外增殖具有显著的抑制作用,能够高效、特异地杀死乳腺癌细胞,为体内治疗乳腺癌提供了一定的理论依据。     

Upregulated hsa_circ_0000129 expression promotes proliferation and migration of breast cancer cells

Circular RNAs (circRNAs) are considered potential biomarkers in the pathogenesis and detection of several types of cancer. The present study aimed to investigate the role of hsa_circ_0000129 in the pathogenesis and molecular mechanism underlying breast cancer. A total of 68 pairs of breast cancer and corresponding paracancerous tissue samples, three different breast cancer cell lines (MCF-7, MDA-MB-231 and MDA-MB-468) and a normal human breast cell line (MCF-10A) were used to investigate the expression of hsa_circ_0000129. The effect of hsa_circ_0000129 on cell proliferation, migration and colony formation was assessed in MCF-7 and MDA-MB-468 cells, along with the expression of enhancer of zeste homolog 2 (EZH2). The results demonstrated that hsa_circ_0000129 expression was significantly higher in breast cancer tissues compared with normal tissues. In addition, high hsa_circ_0000129 expression was significantly associated with lymph node metastasis and a higher tumor-node-metastasis stage. Comparisons between the breast cancer cell lines (MCF-7, MDA-MB-231 and MDA-MB-468) and MCF-10A cells indicated similar results. MCF-7 cells overexpressed with hsa_circ_0000129 significantly increased cell proliferation, migration and colony formation compared with the negative control group, the effects of which were reversed following hsa_circ_0000129 knockdown in MDA-MB-468 cells. Furthermore, EZH2 expression was positively associated with hsa_circ_0000129 expression. Taken together, the results of the present study suggest that hsa_circ_0000129 may represent a promising prognostic biomarker for breast cancer. In addition, the role of hsa_circ_0000129 in breast cancer cell lines indicates a mechanism for tumorigenesis, as well as a potent target for the treatment of malignant progression.     

CD24 enhances DNA damage-induced apoptosis by modulating NF-κB signaling in CD44-expressing breast cancer cells

Cluster of differentiation 24 (CD24) is a small glycosylphosphatidylinositol-linked cell surface molecule that is expressed in a variety of human carcinomas, including breast cancer. To determine the role of CD24 in breast cancer cells, we expressed CD24 in CD24-negative/low and cluster of differentiation 44 (CD44)-positive MDA-MB-231 metastatic breast cancer cells. Forced expression of CD24 resulted in a decrease in c-Raf/mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK)/mitogen-activated protein kinase signaling and reduced cell proliferation. Apoptosis induced by DNA damage was greatly enhanced in MDA-MB-231 CD24 cells as compared with MDA-MB-231 vec cells. CD24 expression efficiently attenuated DNA damage-induced nuclear factor-kappaB (NF-κB) signaling in MDA-MB-231 cells. However, in CD24-positive and CD44-negative/low MCF-7 cells, knockdown of CD24 did not significantly affect DNA damage-induced apoptosis nor NF-κB signaling. Silencing of CD24 in CD24/CD44-double-positive MDA-MB-468 cells partially rescued DNA damage-induced apoptosis. Transient transfection studies with 293T cells also revealed that CD24 attenuated cell viability and NF-κB signaling only when CD44 was cotransfected. These data indicate that CD24 expression potentiated DNA-induced apoptosis by suppressing antiapoptotic NF-κB signaling in CD44-expressing cells.     

沉默CD44表达对乳腺癌细胞MDA-MB-231增殖与侵袭的影响

目的:探索乳腺癌细胞MDA-MB-231及MCF-7中CD44分子的表达水平差异及沉默CD44对乳腺癌细胞MDA-MB-231增殖、侵袭和迁移的影响。方法:利用qRT-PCR及Western blot技术检测细胞中CD44基因表达水平;设计并合成CD44的siRNA片段(CD44-siRNA)转染乳腺癌细胞,利用qRT-PCR、Western blot技术检测细胞中CD44基因表达水平的变化;MTT检测MDA-MB-231细胞增殖;Transwell侵袭实验检测MDA-MB-231细胞的迁移与侵袭能力变化。结果:CD44在侵袭性乳腺癌细胞MDA-MB-231中的表达高于非侵袭性乳腺癌细胞MCF-7,CD44-siRNA下调了 MDA-MB-231细胞中CD44 mRNA与蛋白水平的表达,并抑制了细胞的增殖和侵袭转移能力。结论:CD44-siRNA能够下调CD44的表达,并有效抑制乳腺癌细胞MDA-MB-231的增殖及其侵袭迁移力。     

Breast cancer stromal fibroblasts promote the generation of CD44+CD24- cells through SDF-1/CXCR4 interaction

Background

Breast cancer stem cells (BCSCs) have been recently identified in breast carcinoma as CD44⁺CD24^- cells, which exclusively retain tumorigenic activity and display stem cell-like properties. Using a mammosphere culture technique, MCF7 mammosphere cells are found to enrich breast cancer stem-like cells expressing CD44⁺CD24^-. The stromal cells are mainly constituted by fibroblasts within a breast carcinoma, yet little is known of the contributions of the stromal cells to BCSCs.

Methods

Carcinoma-associated fibroblasts (CAFs) and normal fibroblasts (NFs) were isolated and identified by immunohistochemistry. MCF7 mammosphere cells were co-cultured with different stromal fibroblasts by a transwell cocultured system. Flow cytometry was used to measure CD44 and CD24 expression status on MCF7. ELISA (enzyme-linked immunosorbent assay) was performed to investigate the production of stromal cell-derived factor 1 (SDF-1) in mammosphere cultures subject to various treatments. Mammosphere cells were injected with CAFs and NFs to examine the efficiency of tumorigenity in NOD/SCID mice.

Results

CAFs derived from breast cancer patients were found to be positive for α-smooth muscle actin (α-SMA), exhibiting the traits of myofibroblasts. In addition, CAFs played a central role in promoting the proliferation of CD44⁺CD24^- cells through their ability to secrete SDF-1, which may be mediated to SDF-1/CXCR4 signaling. Moreover, the tumorigenicity of mammosphere cells with CAFs significantly increased as compared to that of mammosphere cells alone or with NFs.

Conclusion

We for the first time investigated the effects of stromal fibroblasts on CD44⁺CD24^- cells and our findings indicated that breast CAFs contribute to CD44⁺CD24^- cell proliferation through the secretion of SDF-1, and which may be important target for therapeutic approaches.     

抑制CC类趋化因子配体5基因表达对乳腺癌细胞增殖能力的影响

目的 探讨抑制CC类趋化因子配体5(CCL5)基因表达对人乳腺癌细胞增殖能力的影响.方法 用特异性CCL5 RNA干扰(RNAi)序列慢病毒载体感染人乳腺癌细胞MCF-7和MDA-MB-231,分别为KD1组和KD2组;另在MCF-7和MDA-MB-231细胞中分设阴性病毒载体感染的阴性对照组(NC1组和NC2组)和未感染组(CON1组和CON2组).采用实时定量逆转录聚合酶链反应(RT-PCR)检测转染病毒后乳腺癌细胞中CCL5的表达,四甲基偶氮唑蓝(MTT)比色法和流式细胞术(FACS)分析细胞的增殖情况,平板克隆形成实验观察细胞的克隆形成能力.结果 CCL5 RNAi慢病毒可显著降低MCF-7和MDA-MB-231细胞中CCL5基因的表达.MTF法检测结果显示,在不同的培养时间,MCF-7和MDA-MB-231细胞的KD组、NC组与CON组细胞培养上清A值差异均无统计学意义(均P＞0.05).FACS分析结果显示,KD1组、NC1组和CON1组的增殖指数(PI)值分别为0.48±0.03、0.43±0.01和0.45±0.02;KD2组、NC2组和CON2组的PI值分别为0.48±0.02、0.44±0.05和0.47±0.02(两两比较,均P＞0.05).荧光显微镜下观察显示,KD组的克隆体积及每克隆的细胞数明显小于NC组和CON组.KD1组和KD2组克降数目(0.34±0.08和0.33±0.10)明显少于NC1组(0.81±0.12)、NC2组(0.97±0.09)、CON1组(0.92±0.12)和CON2组(1.04±0.07),差异有统计学意义(P＜0.05).结论 CCL5基因的表达下调对乳腺癌MCF-7和MDA-MB-231细胞群体倍增时间无明显影响,但可显著降低细胞的克隆形成能力,从而使肿瘤细胞的恶性增殖受到抑制.

Abstract：

Objective To investigate the effect of suppression of CCI5 ligand gene on the proliferation of human breast cancer cells. Methods A lentiviral vector carrying a short interfering RNA (siRNA) targeting CCL5 was transfected into human breast cancer cell line MCF-7 and MDA-MB-231 cells.The expression of CCL5 mRNA in the cells was detected by real-time PCR. The proliferation of MCF-7 and MDA-MB-231 cells was assessed by MTT assay and FACS assay, and the colony formation ability of both cell lines were measured, respectively. Results Real time PCR showed a good knockdown effect of CCL5 in both cell-lines. Colony-forming assay showed that the ability of colony formation of MCF-7/CCL5-siRNA and MDA-MB-231/CCL5-siRNA was decreased markedly. The colony number of MCF-7/CCL5-siRNA group was (0. 34 ± 0. 08), significantly lower than 0. 81 ± 0. 12 in the MCF-7/CCL5-N group and 0.92 ± 0.12 in the MCF-7 group (P ＜ 0. 05). The colony number of MDA-MB-231/CCL5-siRNA group was 0. 33 ± 0. 10,significantly lower than 0.97 ±0.09 in the MDA-MB-231/CCL5-N group and 1.04 ±0.07 in the MDA-MB-231 group (P ＜0.05). However, MTT assay revealed that the proliferation of MCF-7/CCL5-siRNA cells was not significantly different from that of MCF-7/CCL5-N or MCF-7 cells, respectively (P ＞0.05), and the same result was found in MDA-MB-231 cells. FACS assay showed that the proliferation index (PI) of groups MCF-7/CCL5-siRNA, MCF-7/CCL5-N and MCF-7 were 0.48 ± 0. 03, 0. 43 ± 0. 01 and 0.45 ±0. 02. The PI of groups MDA-MB-231/CCL5-siRNA, MDA-MB-231/CCL5-N and MDA-MB-231 cells were 0. 48 ± 0.02, 0.44 ± 0.05 and 0. 47 ± 0. 02. There was no statistical difference among them ( P ＞ 0.05 ).Conclusion The down-regulation of CCL5 gene in human breast cancer cells may significantly suppress their colony formation ability, rather than affecting their population doubling time to some extent.