慢病毒介导的shRNA干扰人HepG2.2.15细胞Akt2基因表达的研究

目的针对Akt2基因构建shRNA慢病毒干扰载体并评价慢病毒介导的RNA干扰在人HepG2.2.15中的基因沉默效应。方法设计Akt2的RNAi寡聚核苷酸序列,利用慢病毒载体构建Akt2的shRNA载体,转染入大肠埃希菌并观察重组表达状况,利用293T细胞包装得到重组腺病毒,以绿色荧光蛋白(GFP)作为标记,逐孔稀释法确定转染效率及滴度,以实时荧光定量法比较各组对Akt2 mRNA的干扰效果。结果筛选了所构建的3个Akt2靶向序列,包装shRNA慢病毒后转染HepG2.2.15细胞,慢病毒转染后的沉默效率可达85%,比较得出沉默效率最高的靶序列和工作条件。结论本研究成功构建并筛选了针对Akt2的shRNA慢病毒载体,有效抑制HepG2.2.15细胞中Akt2 mRNA的表达。     

脂质体介导转染的绿色荧光蛋白基因在骨髓基质细胞内的表达

目的研究脂质体转染法对骨髓基质细胞进行基因修饰的可行性。方法在体外分离和扩增大鼠骨髓基质细胞,用脂质体转染法介导绿色荧光蛋白基因进入到骨髓基质细胞内,荧光显微镜下检测荧光蛋白的表达,台盼兰排斥试验检测转染细胞的活力。结果绿色荧光蛋白可以在大鼠骨髓基质细胞内表达,转染效率为(28.9±3.6)%;脂质体法转染后的细胞活力为(93.6±4.8)%。结论脂质体转染法可以介导外源基因进入到骨髓基质细胞内表达。     

siRNA介导COX-2基因沉默对大肠癌LoVo细胞侵袭及上皮间质转化的影响

目的探讨靶向沉默环氧合酶-2(cyclooxygenase-2,COX-2)表达对大肠癌LoVo细胞侵袭能力及上皮间质转化的影响。方法在体外COX-2 siRNA转染大肠癌LoVo细胞,RT-PCR及免疫印迹法验证转染后COX-2 mRNA及蛋白表达,Transwell小室法检测细胞侵袭能力的改变;免疫印迹法检测EMT标志物(E-cadherin、Vimentin、Fibronectin)、ERK/MAPK和PI3K/Akt通路相关蛋白(Akt、p-Akt、p-GSK-3β、ERK、p-ERK)及MMP-9表达的变化情况。结果 COX-2 siRNA转染大肠癌LoVo细胞后,COX-2 mRNA及蛋白表达下调,同时细胞侵袭能力降低;上皮标记物E-cadherin表达上调,同时间叶标记物Vimentin和Fibronectin表达下调;细胞总的ERK、Akt蛋白表达水平无明显改变,而p-ERK、p-Akt表达降低,同时,Akt下游效应蛋白p-GSK-3β表达也下调; MMP-9表达下调。结论 COX-2 siRNA转染有效抑制了大肠癌LoVo细胞COX-2表达,并可能通过阻滞细胞ERK/MAPK和PI3K/Akt通路,进而抑制EMT,下调MMP-9表达,降低细胞侵袭能力。     

蛋白激酶B调节骨桥蛋白在肝癌HepG2细胞中的表达

目的 转移相关基因骨桥蛋白(OPN)在肝癌中的表达方式、途径尚不清楚，检测OPN在HepG2细胞中转染蛋白激酶B(Akt)前后的表达，旨在探讨磷脂酰肌醇3激酶信号途径中的关键基因Akt与OPN表达的关系。方法 用脂质体介导的基因转染法将含有Akt基因的质粒转染HepG2细胞，并用Western blot鉴定；OPN的表达用Northern blot和Western blot方法检测。结果 Akt基因成功转染HepG2细胞，Western blot能检测到HepG2细胞中外源表达的Akt基因；Northern blot和Western blot检测发现，Akt在核酸和蛋白水平调节OPN的表达；在无血清培养条件下，OPN在HepG2中结构性表达量很少或无表达,转染活性型Akt后OPN表达升高；在有血清培养条件下,HepG2细胞转染缺陷型Akt基因后OPN表达下降。结论 Akt调节转移相关基因OPN在肝癌细胞中的表达，提示可通过使Akt基因失活来阻断OPN产生，从而抑制肝癌转移。     

高表达整合素连接激酶促进脐静脉内皮细胞增殖

目的探讨高表达整合素连接激酶对体外培养人脐静脉内皮细胞增殖的影响。方法利用高表达整合素连接激酶的腺病毒转染脐静脉内皮细胞,诱导其在脐静脉内皮细胞中高表达。采用噻唑蓝法、流式细胞术、EDU法检测脐静脉内皮细胞增殖能力;Western blot检测脐静脉内皮细胞蛋白激酶B(Akt)、内皮型一氧化氮合酶(eNOS)蛋白表达及其蛋白磷酸化水平。结果整合素连接激酶在脐静脉内皮细胞高表达后,噻唑蓝法、流式细胞术、EDU法检测结果均表明:整合素连接激酶病毒转染组细胞增殖能力明显高于空病毒转染对照组(P<0.05或P<0.01)。Western blot检测发现整合素连接激酶病毒转染组蛋白激酶B、内皮型一氧化氮合酶磷酸化水平较对照组明显升高(P<0.05),而蛋白激酶B、内皮型一氧化氮合酶的表达水平两组间无差异。结论整合素连接激酶能促进脐静脉内皮细胞增殖,其机制可能通过激活下游Akt/eNOS通路。     

NIRF基因通过PI3K/Akt信号通路诱导人肺癌细胞凋亡

目的探究NIRF基因对人肺癌细胞凋亡的影响以及机制研究。方法使用重组质粒siRNANIRF(siRNA-NIRF组)和空载体(siRNA-NC组)转染人肺癌细胞A549,以未转染细胞为对照(Control组),免疫印迹试验(Western blot)检测转染效果;噻唑蓝(MTT)检测转染细胞增殖情况,使用流式细胞术检测转染细胞凋亡状况,蛋白免疫印迹(Western blot)检测细胞中蛋白激酶B(Akt)、磷酸化Akt(p-Akt)、磷脂酰肌醇-3激酶(PI3K)、磷酸化PI3K(p-PI3K)蛋白的表达量。结果转染重组质粒siRNA-NIRF后,细胞中NIRF蛋白的表达量显著低于对照组(P0.05);与对照组相比,siRNA-NIRF组细胞的存活率显著降低(P0.05),凋亡率显著增高(P0.05),siRNA-NC组无明显差异(P0.05);与对照组相比,siRNA-NIRF组和siRNA-NC细胞中Akt、PI3K蛋白的含量无明显变化(P0.05),但siRNA-NIRF组细胞中p-Akt和p-PI3K的含量显著低于对照组(P0.05)。结论干扰NIRF基因可抑制肺癌细胞A549增殖,促进其凋亡,其作用机制是影响PI3K/Akt信号通路的关键因子的表达量。     

RNA干扰HIF-1α对食管癌细胞株TE13的生物学特性的影响

目的:探讨HIF-1α仅沉默后对食管癌细胞株TE13的生物学行为的影响.方法:应用倒置荧光显微镜观察HIF-1α的干扰质粒转染食管癌细胞TE13后绿色荧光蛋白的表达:采用、Western blot方法检测HIF-1α蛋白的表达;四甲基偶氮唑蓝(MTT)法检测转染前后细胞增殖能力的变化:Transwell方法检测干扰前后细胞迁移能力的变化;流式细胞术检测干扰前后细胞周期的变化.结果:TE13/12单克隆干扰效果好,Westernblot结果显示无HIF-1α表达.HIF-1α被干扰后,细胞增殖能力明显减弱(p<0.05),运动迁移能力显著下降,与未转染的细胞相比穿过人工基底膜的细胞数明显减少(18.2±3.7 VS 103.8±8.5,P<0.05).与未转染组相比,TE13/12的细胞周期发生变化,G2/M期细胞明显减少(5.99%±1.19% vs 20.47%±4.30%,P<0.05),S期增加(64.67%±1.98%VS 48.53%±3.89%,P<0.05).结论:RNA干扰可引起TE13中HIF-1α的沉默,而HIF-1α表达下调后食管癌细胞株TE13的增殖与迁移能力均减弱.推测阻断HIF-1α通路有可能成为治疗人食管鳞癌的新靶点.     

内皮素-1经蛋白激酶B/雷帕霉素靶蛋白信号通路诱导大鼠肺细小动脉平滑肌细胞肥大

目的 探讨过表达内皮素-1(ET-1)对体外培养的大鼠肺细小动脉平滑肌细胞(RPMC)增殖/肥大的影响及其作用机制研究.方法 采用组织灌注法体外分离培养RPMC,脂质体介导法瞬时转染ET-1基因,经实时荧光定量逆转录-PCR和免疫印迹法鉴定后,用流式细胞技术检测细胞周期和细胞体积的变化,用免疫印迹法和细胞免疫荧光法检测α-平滑肌肌动蛋白(α-SMA)的表达,同时检测细胞总蛋白/总DNA比值的变化,并用免疫印迹法检测蛋白激酶B(Akt/PKB)、雷帕霉素靶蛋白(mTOR)和细胞外信号调节激酶(ERK1/2)的磷酸化水平.采用SPSS 11.0统计软件处理数据,各组间比较均采用t检验.结果 成功分离和培养RPMC并瞬时转染ET-1基因.与空载相比,转染48 h后RPMC细胞周期分布和细胞增殖指数未见明显差异,但转染72 h后检测到α-SMA合成功能增强,分别为空载转染组的1.3倍和1.2倍,细胞总蛋白/总DNA比也增高,分别为空载转染组的1.6倍和1.5倍.流式细胞术检测显示,与空载相比,转染72 h后RPMC细胞体积增大,分别为空载转染组的1.1倍和1.2倍.免疫印迹法检测显示,转染48 h后,Akt/PKB和mTOR的磷酸化水平升高,ERK1/2的磷酸化水平降低.结论 过度表达ET-1可能经Akt/PKB-mTOR信号通路诱导RPMC肥大,在肺动脉高压的血管重塑过程中发挥重要作用.     

LIMD1经Akt/ERK信号通路抑制食管癌细胞增殖

目的探讨LIMD1对食管癌发生发展的影响及分子机制。方法构建LIMD1干扰质粒,稳定转染食管癌细胞KYSE30;采取Western blot验证LIMD1干扰效率; MTT检测LIMD1干扰前后细胞增殖变化; Western blot检测增殖相关蛋白Akt和ERK表达水平;裸鼠移植瘤模型探讨LIMD1对成瘤生长的影响。结果成功构建LIMD1干扰质粒并稳转食管癌细胞KYSE30细胞株。与对照组比较,实验组干扰LIMD1转染后KYSE30细胞的增殖能力受到明显增强(P 0. 01),且Akt和ERK蛋白表达水平均明显增加。较对照组而言,移植瘤实验显示实验组裸鼠肿瘤生长增快(P 0. 01)。结论 LIMD1通过调节Akt和ERK途径抑制食管癌细胞增殖。     

绿色荧光蛋白基因在骨髓基质细胞内表达的意义

在体外分离和扩增大鼠骨髓基质细胞,用脂质体转染法介导绿色荧光蛋白基因进入骨髓基质细胞内,荧光显微镜下检测荧光蛋白的表达,台盼蓝排斥试验检测转染细胞的活力。结果绿色荧光蛋白在转染大鼠骨髓基质细胞24h后开始表达,48~96h表达最强,转染效率为(28.9±3.6)%;然后逐渐降低,2周后仍可见少量表达。提示外源基因可以在骨髓基质细胞内高效表达。     

Angiopoietin-1 targeted RNA interference suppresses angiogenesis and tumor growth of esophageal cancer

AIM： To determine the inhibitory effect of the adenovirusbased angiopoietin-1 （Ang-1） targeted small interfering RNA expression system （Ad/Ang-1si） on the expression of the Ang-1 gene, cell growth and apoptosis in human esophageal cancer cell line Eca109. METHODS： siRNA-expressing adenovirus targeting Ang-1 gene was constructed using the Ad Easy System. Cultured Eca109 cells were transfected with Ad/Ang-1si （Eca109/Ang-1si）, and Ad/si was used to infect Eca109 cells as control （Eca109/si）. Ang-1 gene expression and concentration was determined with RT-PCR and ELISA, respectively. Human umbilical vein endothelial cell （HUVEC） migration and proliferation were analyzed. After s.c. injection into athymic nu/nu mice, the tumor growth, vessel density and apoptosis of each group was also determined. RESULTS： HUVEC migration induced by conditioned medium from Ang-1si-transfected Eca109 cells was significantly less than that induced by conditioned medium from Eca109 cells and control adenovirustransfected Eca109 cells. Furthermore, after s.c. injection into athymic nu/nu mice, the tumor growth and cell apoptosis of Ad/Ang-1si -expressing Eca109 cells was significantly lower than that of parental or control adenovirus-transfected cells. Vessel density assessed by CD31 immunohistochemical analysis and Ang-1 expression by RT-PCR were also decreased. CONCLUSION： The targeting Ang-1 may provide a therapeutic option for esophageal cancer.     

EphA2在缺氧条件下的表达及其对食管癌细胞体外三维培养的影响

目的:探讨在正常氧分压和缺氧条件下,食管癌细胞中上皮细胞激酶A2(EphA2)表达变化及其对体外三维培养的影响.方法:正常氧分压及缺氧条件下培养食管癌Ecal09及TE13细胞,RT-PCR及Western blot 分别监测细胞中EphA2表达的变化:EphA2 miRNA干扰质粒转染Ecal09和TE13细胞后,采...     

磁性纳米控释紫杉醇对食管癌Eca109细胞株生长的影响

目的:观察不同浓度磁性纳米控释紫杉醇对食管癌细胞Eca109的影响及与不同化疗药物的对比.方法:取对数生长期的食管癌Eca109细胞作细胞增殖抑制实验,实验组分别给予不同浓度的磁性纳米控释紫杉醇和5-氟尿嘧啶、泰素,同时设立二甲基亚砜(DMSO)和RPMI1640液对照,测定24,48,72h三个时间段的吸光度值,计算抑制率.经不同浓度的磁性纳米控释紫杉醇作用72h后,用电镜观察细胞超微结构,同时用流式细胞仪测定细胞周期和细胞凋亡.结果:MTT实验显示磁性纳米控释紫杉醇可抑制食管癌细胞增殖,与5-氟尿嘧啶,泰素相比,具有缓释性(P<0.01);电镜可发现药物作用组细胞核固缩、解聚以及凋亡小体;流式细胞仪检测显示G1峰前有明显的凋亡峰;细胞周期分析提示磁性纳米控释紫杉醇可将Eca109细胞阻滞于G2-M期,且与浓度相关.结论:磁性纳米控释紫杉醇对人食管癌细胞Eca109的生长有明显的抑制作用,使细胞分裂阻滞于G2-M期,并诱导细胞凋亡,且具有缓释效果.     

mi R-382 functions as a tumor suppressor against esophageal squamous cell carcinoma

AIM To explore the effect of mi R-382 on esophageal squamous cell carcinoma(ESCC) in vitro and its possible molecular mechanism.METHODS Eca109 cells derived from human ESCC and Het-1A cells derived from human normal esophageal epithelium were used. Lentivirus-mediated mi R-382 was overexpressed in Eca109 cells. The effect of mi R-382 on cell proliferation was evaluated by MTT and colony formation assay. For cell cycle analysis, cells were fixed and stained for 30 min with propidium iodide(PI) staining buffer containing 10 mg/m L PI and 100 mg/m L RNase A, and analyzed by BD FACSCalibur? flow cytometer. For cell apoptosis assay, cells were stained with an Annexin V-FITC/PI Apoptosis Detection Kit according to the manufacturer's instructions and analyzed by a dual-laser flow cytometer. Cell invasion and migration abilities were determined through use of transwell chambers, non-coated or pre-coated with matrigel. Levels of proteins related to cell growth and migration were examined by western blotting.RESULTS Endogenous mi R-382 was down-regulated in Eca109 cells compared with Het-1A. Introduction of mi R-382 not only significantly inhibited proliferation and colony formation, but also arrested cell cycle at the G2/M phase, as well as promoted apoptosis and autophagy in Eca109 cells. Migration, invasion and epithelialmesenchymal transition of Eca109 cells were suppressed by overexpressing mi R-382. Western blotting results showed that mi R-382 inhibited the phosphorylation of m TOR and 4E-BP1. CONCLUSION mi R-382 functions as a tumor suppressor against ESCC development and metastasis, and could be considered as a potential drug source for the treatment of ESCC patients.     

食管鳞癌中微小核糖核酸let-7的表达及病理生物学意义

目的 探讨微小RNA(miRNA)1et-7对食管鳞癌细胞增殖的影响及食管鳞癌组织中let-7表达水平与临床病理特征间的关系.方法 利用RNA干扰(RNAi)和细胞转染技术将食管鳞癌细胞Eca109分别转染入let-7、let-7抑制剂及随机序列.以正常培养的Eca109细胞为阴性对照组.噻唑蓝(MTT)比色法检测各组Eca109细胞的增殖情况.实时荧光定量聚合酶链反应(qRTPCR)检测各组细胞、45例食管鳞癌组织及其癌旁组织中let-7的表达水平,并分析其与食管鳞癌临床病理特征间的关系.结果 转染后72 h,转染let-7组吸光度(A)值较阴性对照组明显降低(P=0.005),转染let-7抑制剂组A值较阴性对照组明显升高(P=0.029).与阴性对照组let-7表达量比较,转染let-7组表达增加33%(1.33比1.00,P=0.039),转染let-7抑制剂组表达降低50%(0.50比1.00,P=0.014).食管鳞癌组织和癌旁组织中let-7相对表达量的比值为0.66±0.47,差异有统计学意义(P=0.001).汉族患者食管鳞癌组织中let-7相对表达量(0.48±0.43)低于哈萨克族(0.88±0.51,P=0.019).低分化食管鳞癌组织中let-7相对表达量(0.42±0.30)低于高分化食管鳞癌组织(0.84±0.38,P=0.015).有淋巴结转移者食管鳞癌组织中let-7相对表达量(0.50±0.35)低于无淋巴结转移者(0.80±0.52,P=0.032).结论 let-7对食管鳞癌的发生、发展起抑制作用,其表达水平与组织分化程度、淋巴结转移及民族相关.

Abstract：

Objective To estimate the effect of microRNA (miRNA) let-7 expression on human esophageal squamous cell carcinoma(ESCC) and the relationship between let-7 level and clinicopathological parameters. Methods ESCC cell line (Eca109) was transfected with let-7 or its inhibitor by RNAi and cell transfection techniques. Normal cultured Eca109 cell was served as negative control. The proliferation of Eca109 cell was detected by MTT. The expression of let-7 in Eca109 cells and 45 paired ESCC tissues and corresponding para-cancerous tissues were measured using real-time quantitative polymerase chain reaction (qRT-PCR). The relationship between let-7 level and clinicopathological parameters in patients with ESCC was analyzed. Results The A value of let-7 in Eca109 cells transfected with let-7 was lower than negative control (P=0.005), while it was higher in Eca109 cells transfected inhibitor than that in negative control 72 hours after transfection. In comparison with negative control, the expression of let-7 in Eca109 cells transfected with let-7 was increased 33% (1.33 vs 1.00,P=0. 039) and it was decreased 50% in Eca109 cells transfected with inhibitor (0.50 vs 1.00,P=0. 014). The ratio of let-7 expression in ESCC tissue and para-cancerous tissue was 0.66 ± 0.47 with significant differece (P= 0.001). Moreover, The level of let-7 expression in Han patients with ESCC was lower than Kazakh patients with ESCC (0.48±0.43 vs 0. 88±0.51,P=0. 019). The level of let-7 expression in poorly differentiated ESCC tissue was lower than well differentiated ESCC tissue (0.42±0.30 vs 0.84±0.38,P=0. 015). The level of let-7 expression in patients with lymph node metastasis was lower than those without lymph node metastasis (0.50±0.35vs 0. 80±0.52,P=0. 032) . Conclusion It is demonstrated that let-7 can inhibit the carcinogenesis and development of ESCC. The level of let-7 expression is associated with cell differentiation,lymph node metastasis and nationalities.     

Effect of S1P5 on proliferation and migration of human esophageal cancer cells

AIM:To investigate the sphingosine 1phosphate (S1P) receptor expression profile in human esophageal cancer cells and the effects of S1P5 on proliferation and migration of human esophageal cancer cells. METHODS: S1P receptor expression profile in human esophageal squamous cell carcinoma cell line Eca109 was detected by semiquantitative reverse trans cription polymerase chain reaction. Eca109 cells were stably transfected with S1P5EGFP or controlEGFP constructs. The relation between the responses of cell prol...     

Bile salts inhibit growth and induce apoptosis of human esophageal cancer cell line

AIM: To explore the effect of six bile salts, including glycoc holate (GC), glycochenodeoxycholate (GCDC), glycodeoxy cholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and two bile acids including cholic acid (CA) and deoxycholic acid (DCA) on esophageal cancer Ecal09 cell line. METHODS: Eca109 cells were exposed to six bile salts, two bile acids and the mixed bile salts at different concentrations for 24-72 h. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to detect the cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptosis cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptosis DNA ladders on agarose were observed. Activation of caspase-3 was assayed by FCM with FlTC-conjugated monoclonal rabbit anti-active caspase-3 antibody and expressions of Bcl-2 and Bax proteins were examined immunocytochemically in 500 μmol/L-TC-induced apoptosis cells. RESULTS: Five bile salts except for GC, and two bile acids and the mixed bile salts could initiate growth inhibition of Ecal09 cells in a dose- and time-dependent manner. TUNEL, FCM, and DNA ladder assays all demonstrated apoptosis induced by bile salts and bile acids at 500 μmol/L, except for GC. Early apoptosis cell percentages in Eca109 cells treated with GCDC, GDC, TC, TCDC, TDC, CA at 500 μmol/L for 12 h, DCA at 500 μmol/L for 6 h, and mixed bile salts at 1 000 μmol/L for 12 h were 7.5%, 8.7%, 14.8%, 8.9%, 7.8%, 9.3%, 22.6% and 12.5%, respectively, all were significantly higher than that in control (1.9%). About 22% of the cell population treated with TC at 500 μmol/L for 24 h had detectable active caspase-3, and were higher than that in the control (1%). Immunocytochemical assay suggested that TC down-regulated Bcl-2 protein level and up-regulated Bax protein level. CONCLUSION: GCDC, GDC, TC, TCDC, TDC, CA and DCA, except for GC, can inhibit growth and induce apoptosis of esophageal cancer Ecal09 cells. Activation of caspase-3, decreased Bcl-2 protein and increased Bax protein are involved in TC-induced apoptosis of Ecal09 cells.     

HIF-1α induces VE-cadherin expression and modulates vasculogenic mimicry in esophageal carcinoma cells

AIM: To investigate whether hypoxia inducible factor (HIF)-1α modulates vasculogenic mimicry (VM) by upregulating VE-cadherin expression in esophageal squamous cell carcinoma (ESCC).METHODS: Esophageal squamous cancer cell lines Eca109 and TE13 were transfected with plasmids harboring small interfering RNAs targeting HIF-1α or VE-cadherin. The proliferation and invasion of esophageal carcinoma cells were detected by MTT and Transwell migration assays. The formation of tubular networks of cells was analyzed by 3D culture in vitro. BALB/c nude mice were used to observe xenograft tumor formation. The relationship between the expression of HIF-1α and VE-cadherin, ephrinA2 (EphA2) and laminin5γ2 (LN5γ2) was measured by Western blot and real-time polymerase chain reaction.RESULTS: Knockdown of HIF-1α inhibited cell proliferation (32.3% ± 6.1% for Eca109 cells and 38.6% ± 6.8% for TE13 cells, P < 0.05). Both Eca109 and TE13 cells formed typical tubular networks. The number of tubular networks markedly decreased when HIF-1α or VE-cadherin was knocked down. Expression of VE-cadherin, EphA2 and LN5γ2 was dramatically inhibited, but the expression of matrix metalloproteinase 2 had no obvious change in HIF-1α-silenced cells. Knockdown of VE-cadherin significantly decreased expression of both EphA2 and LN5γ2 (P < 0.05), while HIF-1α expression was unchanged. The time for xenograft tumor formation was 6 ± 1.2 d for Eca109 cells and Eca109 cells transfected with HIF-1α Neo control short hairpin RNA (shRNA) vector, and 8.4 ± 2.1 d for Eca109 cells transfected with an shRNA against HIF-1α. Knockdown of HIF-1α inhibited vasculogenic mimicry (VM) and tumorigenicity in vivo.CONCLUSION: HIF-1α may modulate VM in ESCC by regulating VE-cadherin expression, which affects VM formation through EphA2 and LN5γ2.     

Role of stress-activated MAP kinase P38 in cisplatin- and DTT-induced apoptosis of the esophageal carcinoma cell line Eca109

AIM: To study the role of P38 kinase in esophageal cancer cell apoptosis induced by genotoxin, cisplatin and the unfolded protein response (UPR) inducer, dithiothreitol (DTT). METHODS: Esophageal carcinoma cell line Eca109 was cultured in RPMI 1640 medium to 70% confluency and treated with either cisplatin, DTT, or cisplatin plus DTT in the presence or absence of P38 inhibitor, SB203580. The untreated cells served as the control. The esophageal carcinoma cell apoptosis was detected by agarose gel DNA ladder analysis and quantified by flow cytometry. The P38 phosphorylation was detected by immunohis-tochemistry using antibodies specific to phosphorylated P38 protein. RESULTS: (1) Both cisplatin and DTT induced apoptosis in the esophageal cancer cell line Eca109 as shown by DNA ladder formation; (2) As detected by antibodies specific for the phosphorylated P38 protein (p-P38), both cisplatin and DTT treatments activated the stress-activated enzyme, MAP kinase P38. The number of positive cells was about 50% for the treatment groups, comparing to that of 10% for untreated group. DTT treatment, but not cisplatin treatment, induces nuclear localization of p-P38; (3) As measured by flow cytometry, inhibition of P38 activity by SB203580 blocks DTT- and cisplatin-induced apoptosis. The rates for DTT, cisplatin, and DTT plus cisplatin-induced apoptosis were 16.8%, 17.1%, and 21.4%, respectively. Addition of the SB compound during the incubation reduced the apoptotic rate to about 7.6% for all the treatment groups, suggesting that P38 activation is essential for cisplatin- and DTT-induced apoptosis in Eca109 cells. CONCLUSION: (1) Both DTT and cisplatin were able to induce apoptosis in esophageal cancer cell line Eca109; (2) P38 MAP kinase is essential for DTT- and cisplatin- induced apoptosis in Eca109 cells; (3) P38 activation may be the common signaling component relaying the multiple upstream signaling events to the downstream cell death program.