转录因子SOX9基因对脑胶质瘤干细胞干性维持的相关性研究

目的:应用慢病毒干扰SOX9的表达,观察其对脑胶质瘤干细胞干性维持的影响。方法:设计2条针对SOX9转录短发夹RNA(sh RNA)的DNA序列,构建慢病毒并感染胶质瘤细胞系U87、U251细胞,利用嘌呤霉素筛选稳转细胞。在转录水平及蛋白水平检测SOX9的沉默效果,利用荧光实时定量PCR(q RT-PCR)及免疫荧光染色检测相应干细胞相关标志分子SOX2、Nestin的表达差异。比较诱导形成的胶质瘤干细胞成球能力(肿瘤干细胞成球的直径),同时利用荧光实时定量PCR(q RT-PCR)及免疫荧光染色对干细胞相关标志物SOX2、Nestin的表达水平进行比较。结果:SOX9成功包装慢病毒并有效感染U87、U251细胞,实时荧光定量PCR检测其抑制率分别可降低83.74%和80.12%。并且在稳转细胞系水平相关干细胞标志分子表达含量有明显下降。在干细胞层面沉默SOX9可以明显抑制胶质瘤细胞诱导成球的直径(P0.01),同时免疫荧光显示肿瘤干细胞相关干性分子SOX2、Nestin的表达水平较对照组明显降低。结论:慢病毒感染沉默SOX9基因可以抑制胶质瘤干细胞干性的维持,为胶质瘤的生物治疗提供了重要的靶点。     

成人胰腺导管干细胞的体外分离、纯化、培养及鉴定

目的:建立人胰腺导管干细胞的体外分离、纯化、培养及鉴定的方法.方法:胶原酶分次消化剪切的人胰腺组织,经过Ficoll密度梯度离心后去除胰岛组织,培养于含,10%胎牛血清的CMRL1066培养液中,7-10天可行成单层细胞,用0.25%胰酶-EDTA消化并传代培养.取2-3代细胞利用免疫荧光染色和RT-PCR方法检测CK19、Pdx-1、Nestin、Insulin及Glucagon的表达.结果:经过胶原酶消化、Ficoll密度梯度离心及后续的培养,去除了胰岛组织及外分泌腺,可获得较纯化的鹅卵石样的胰腺导管细胞.免疫荧光结果示:胰腺导管细胞CK19、Pdx-1和Nestin染色呈阳性,阳性细胞率分别为(87.5±6.2)%、(77.5±8.6)%和(50.9±9.5)%,而Insulin染色为阴性.RT-PCR结果显示该细胞表达CK19、Pdx-1和Nestin基因,而未观察到Insulin及Glueagon基因的表达.结论:该方法可较好的分离纯化出人胰腺导管细胞,经鉴定获得细胞具有胰腺干细胞的特性.     

共表达外源OCT4/SOX2能够激活人胚肾细胞中内源NANOG的转录

自2006年诱导多能干细胞（iPS）技术诞生以来,采用病毒等载体进行的诱导方法已取得了成功,但是其致瘤性的影响限制了病毒载体的推广与应用,而采用非病毒载体诱导iPS细胞成为研究的热点. 本研究通过两个启动子的独立启动,构建了带有绿色荧光标记的OCT4/SOX2共表达诱导载体(pOct4/Sox2-EGFP). 将该载体转染HEK 293FT 细胞后,阳性克隆明显表达绿色荧光,并通过RT-PCR,免疫荧光等方法证明其中的转录因子OCT4和SOX2能在转染细胞中高效表达,同时诱导受体细胞中内源NANOG的转录表达. 本研究说明OCT4/SOX2共表达载体能激活NANOG基因的内源表达,暗示着非病毒不整合载体pOct4/Sox2-EGFP本身或与其它转录因子和小分子结合可用于诱导成体细胞的重编程. 因此,本研究为下一步应用质粒载体诱导体细胞重编程为iPS细胞的研究奠定了工作基础.     

低浓度血清促进胚胎肝祖细胞诱导分化

为了探讨不同血清浓度诱导培养条件下对体外诱导胚胎肝祖细胞成熟分化的影响。本研究选用含有10%FBS、5%FBS、2%FBS的DMEM/HGF/FGF4肝细胞培养基体外诱导胚胎肝祖细胞的成熟分化,分别于诱导后0d、3d、6d、9d、12dALB-GLuc检测细胞白蛋白的合成水平,细胞计数检测细胞的成长曲线。RT-PCR检测肝细胞相关标志DLK、AFP、CK18,免疫荧光检测ALB、UGT1A的表达情况。ICG摄取和尿素氮检测肝细胞成熟功能。诱导后第三天,ALB-GLuc开始增高,于第9天达高峰,2%FBS组ALB-GLuc读数最高。生长曲线显示低血清浓度下细胞的增殖速度明显慢于高血清浓度。RT-PCR和免疫荧光结果显示诱导后第9天,3个诱导组DLK、AFP表达低于无诱导组,CK18、ALB、UGT1A均高于无诱导组,2%FBS组差异最显著。3个诱导组的肝细胞ICG摄取能力明显增高,2%FBS组ICG阳性细胞数为(60.2±9.0)%,明显高于5%FBS(45.0±3.6)%及10%FBS组(35.2±2.9)%,诱导后肝细胞的尿素合成功能增强,尤其是2%FBS组。低浓度血清培养条件能更好的诱导胚胎肝祖细胞的体外成熟分化。     

人胎肝干细胞的分离培养、鉴定及mRNA转录分析

目的：探讨体外大量扩增培养人胎肝干细胞的方法,研究其形态、特性及mRNA转录情况。方法：采用两步灌流法结合链霉蛋白酶消化及Percoll密度梯度离心法分离12～20周胎龄的胎肝细胞,采用免疫细胞化学染色及RT-PCR方法对分离培养的细胞进行鉴定分析。结果：刚分离的细胞活力在80%以上,原代培养3d开始出现小细胞团,2周后即形成肉眼可见的细胞集落,细胞体积小,核质比大;原代、传代培养的胎肝细胞甲胎蛋白（AFP）、细胞角蛋白19（CK19）、卵圆标记蛋白OV-6、细胞分化抗原34免疫染色阳性;RT-PCR分析证明胎肝干细胞中AFP、白蛋白、CK19、CK18和八聚体结合蛋白（OCT）-4mRNA的表达。结论：分离了胎肝干细胞,具有肝细胞、胆管细胞及干细胞表面标志及相应的基因表达,为进一步的基础研究奠定了基础。     

再生胰腺提取物诱导人羊膜间充质干细胞定向分化为胰岛素分泌细胞

利用天然生物诱导剂大鼠再生胰腺提取物(Rgenerating pancreatic extract,RPE)定向诱导人羊膜间充质干细胞(Human amniotic mesenchymal stem cells,hAMSCs)向胰岛素分泌细胞分化。切除大鼠60%胰腺刺激胰腺再生,而后制备RPE,以终浓度为20 mg/L的RPE诱导hAMSCs。实验通过形态学鉴定、双硫腙染色、免疫荧光分析、RT-PCR基因检测和高糖刺激胰岛素分泌等实验鉴定细胞诱导结果。实验结果显示P3代hAMSCs经RPE诱导后形态变化明显,诱导15 d后细胞呈簇状生长,经双硫腙染色可见棕红色细胞团;免疫荧光染色结果显示诱导细胞呈胰岛素阳性表达;RT-PCR实验证明诱导细胞阳性表达人胰岛相关基因Pdx1和insulin;高糖刺激实验证明培养液中有胰岛素成分产生,且分泌量随刺激时间的延长先增加而后趋于稳定。实验结果表明hAMSCs在体外经RPE诱导可以分化为胰岛素分泌细胞。     

敲低SOX2基因抑制乳腺癌干细胞的含量

目的:构建敲低SOX2基因的慢病毒表达载体,研究敲低SOX2基因对乳腺癌干细胞含量的影响。方法:将SOX2基因短发夹RNA(sh RNA)序列构建到慢病毒表达载体,利用293T细胞包装并获得敲低SOX2基因的病毒,后在MCF-7、T47D细胞系中构建敲低SOX2基因的稳定克隆,Western印迹检测SOX2蛋白的表达水平,q RT-PCR检测SOX2 m RNA水平的变化,利用流式细胞术检测敲低SOX2基因后乳腺癌干细胞含量的变化。结果:构建了表达SOX2基因sh RNA的慢病毒表达载体,在乳腺癌细胞中敲低SOX2基因后,CD44+/CD24-/low及乙醛脱氢酶阳性(ALDH+)细胞的比例明显降低。结论:敲低SOX2基因抑制了乳腺癌干细胞的含量。     

ES细胞体外定向分化为成熟肝细胞的实验研究

探讨了肝细胞在胚胎干细胞（ES cell）体外诱导分化系统中成熟分化的条件、机制及其鉴定方法.利用TGF, bFGF、HGF等细胞生长因子进行BALB/c小鼠ES细胞向肝细胞方向的定向诱导.利用反转录聚合酶链反应（RT-PCR）、免疫细胞化学（ICC）和放射免疫法（RIA）动态检测肝细胞特异性基因和蛋白AFP,ALB,G6P,TAT,CK8, CK18等在培养体系中的表达,并测定肝细胞的尿素合成功能,最后测定肝细胞分化率.结果,肝细胞特异基因AFP, ALB,G6P和TAT最早分别于第3、9、11、13天表达,肝细胞特异蛋白AFP,CK8,CK18和ALB最早分别于第7、9、9和11天开始表达.第12天开始检测到尿素出现,浓度为8.3 μmol/L,并随培养时间延长而浓度逐渐增加.最后,测得生长因子诱导组肝细胞的分化率为32％,对照组肝细胞分化率为8%.说明肝细胞可以在ES细胞体外诱导分化系统中出现并成熟分化,bFGF、HGF、OSM等可以明显提高细胞分化率和成熟度,有望成为解决肝功能替代疗法中细胞来源问题的新希望.     

体外诱导骨髓间充质干细胞向肝细胞样细胞方向分化

探讨成纤维生长因子-2(FGF-2)在体外定向诱导大鼠骨髓间充质干细胞(BM-MSCs)向肝细胞样细胞分化的作用及量化关系。体外分离培养大鼠BM-MSCs,将第3代BM-MSCs采用不同剂量的FGF-2诱导。诱导后,在显微镜下观察细胞形态学的改变;用免疫细胞化学法检测白蛋白和CK19的分泌;Shiff染色法检测糖原的分泌。诱导后BM-MSCs由梭形向多角形、卵圆形方向变化,白蛋白、CK19和糖原12 d即有阳性表达,以后随着诱导时间的延长阳性率逐渐升高。20 ng/mL FGF-2诱导比10 ng/mL FGF-2诱导细胞白蛋白、CK19和糖原的表达量均多。20 ng/mL FGF-2具有较强的诱导BM-MSCs向肝细胞样细胞分化的能力。     

小分子化合物体外诱导肝上皮样干细胞-WB细胞表达PDX1

目的：近年来干细胞治疗糖尿病一直是国内外研究人员关注的焦点,而肝细胞向胰岛样细胞转变也是热点之一。本实验应用小分子化合物在体外诱导WB-F344大鼠来源肝上皮样干细胞（简写WB细胞）表达胰腺内分泌前体细胞基因PDX1,建立一种体外诱导WB细胞分化为胰腺内分泌前体细胞的实验方法。方法：选用5-AZA TSA,RA,ITS等小分子化合物,分两步法直接诱导WB细胞分化为表达PDX1的胰腺内分泌前体细胞,用含有不同浓度5-AZA分化培养基诱导WB分化,摸索诱导分化的最佳条件。观察细胞形态变化,RT-PCR及实时定量PCR检测部分基因表达情况,免疫荧光检测PDX1的表达。结果：5AZA 5 uM处理2 d,TSA 1 d,RA联合ITS诱导7天,诱导的WB细胞表达PDX1较1-4 uM 5-AZA诱导强,并表达胰腺内分泌前体细胞的相关基因,NGN3,Neurod,NKX2.2,WB表达的Nestin仍持续表达,Insulin1有少量表达。WB表达的肝干细胞基因如ALB,AFP大量下调,标志分化的基因C/EBP下调。结论：5-AZA,TSA,RA,ITS等小分子化合物能够诱导肝上皮样细胞WB表达PDX1,并且这种诱导分化的细胞具有胰腺内分泌前体细胞特征。本实验进一步证明在体外微环境中,肝干细胞能向胰腺内分泌细胞转化,而肝细胞增极强,为将来干细胞治疗糖尿病提供充足的细胞来源     

干细胞在胰腺癌中的研究进展

胰腺癌是预后程度极差的恶性肿瘤,已初步证实胰腺干细胞可转化为胰腺癌细胞。成功分离和鉴定了胰腺癌干细胞并对其与转移、耐药的关系和信号通路异常的关系进行了初步研究。深入理解干细胞在胰腺癌中的作用,可能根本改变临床胰腺癌防治的方式。     

Effect of proton pump inhibitor on amylase release from isolated pancreatic acini

Proton pump inhibitors (PPIs) could inhibit the secretion of gastric acid. Meanwhile, it could also decrease the secretion of other digestive glands besides gastric parietal cell. As we know, PPIs have been widely used to treat acute pancreatitis, and it is effective in clinical practice. However, research showed the side effect of PPIs on acute pancreatitis. The direct effect of PPI on pancreatic secretion is still unknown. Our experiment investigated the direct effect of PPIs on pancreatic exocrine by isolated pancreatic acini. In our study, isolated pancreatic acini were prepared as previously described by Williams, and cerulein was added to stimulate its secretion. The amylase release in the suspension was determined after the administration of different concentrations of omeprazole and Sandostatin; and its activity was also observed in different time phases. In our in vitro study, all results suggest that omeprazole has no direct repression on amylase release from isolated pancreatic acini.     

Immunoassay-based proteome profiling of 24 pancreatic cancer cell lines

Pancreatic ductal adenocarcinoma is one of the most deadly forms of cancers, with a mortality that is almost identical to incidence. The inability to predict, detect or diagnose the disease early and its resistance to all current treatment modalities but surgery are the prime challenges to changing the devastating prognosis. Also, relatively little is known about pancreatic carcinogenesis. In order to better understand relevant aspects of pathophysiology, differentiation, and transformation, we analysed the cellular proteomes of 24 pancreatic cancer cell lines and two controls using an antibody microarray that targets 741 cancer-related proteins. In this analysis, 72 distinct disease marker proteins were identified that had not been described before. Additionally, categorizing cancer cells in accordance to their original location (primary tumour, liver metastases, or ascites) was made possible. A comparison of the cells' degree of differentiation (well, moderately, or poorly differentiated) resulted in unique marker sets of high relevance. Last, 187 proteins were differentially expressed in primary versus metastatic cancer cells, of which the majority is functionally related to cellular movement.     

Effect of pancreatic polypeptide-antiserum on bombesin-stimulated pancreatic exocrine secretion in dogs

Bombesin is a potent stimulus of both pancreatic protein secretion and plasma pancreatic polypeptide (PP) release in dogs. Physiological plasma levels of PP have been shown to inhibit pancreatic exocrine secretion in dogs. We examined the question whether the concomitant release of PP exerts a suppressive action on the pancreatic exocrine response to bombesin in dogs by measuring pancreatic exocrine secretion with and without in vivo immunoneutralization of PP with a high affinity PP-antiserum. Bombesin was infused in a dose of 150 ng/kg·hr, resulting in a rise of plasma PP from 24±5 to 224±25 pM (p<0.01). Before this bombesin infusion, 7 ml of normal rabbit serum had been administered to the dogs (n=8). At a later stage, the study was repeated after administration of 7 ml of PP-antiserum to the same animals. The bombesin induced increase in pancreatic exocrine secretion during administration of PP-antiserum (flow rate 24±10 ml/hr, protein output 1.35±0.43 g/hr, and bicarbonate output 3.25±1.42 mmol/hr) was not significantly different from that during control rabbit serum (flow rate 21±7 ml/hr, protein output 1.26±0.38 g/hr, and bicarbonate output 3.18±1.10 mmol/hr). It is therefore concluded that the pancreatic exocrine response to bombesin is not affected by the concomitant secretion of PP.     

Pancreatic Cancer: Current Progress and Future Challenges

Pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, remains one of the highly lethal malignancies. The highly refractory nature of clinically advanced disease and lack of a reliable biomarker for early detection are major obstructions in improving patient outcome. The recent efforts, however, in understanding the pancreatic tumor biology have resulted in the recognition of novel addictions as well as vulnerabilities of tumor cells and are being assessed for their clinical potential. This special issue highlights some of the recent progress, complexity and challenges towards improving disease outcome in patients with this lethal malignancy.     

改良单层胰肠吻合术在胰十二指肠切除术带蒂大网膜包埋中的应用

目的:探讨带蒂大网膜包埋的改良单层胰肠吻合法重建消化道的胰十二指肠术的临床疗效。方法:回顾性分析2012年9月-2014年12月在我院行胰十二指肠切除术带蒂大网膜包埋改良单层胰肠吻合术的34例患者的临床资料。统计患者的手术时间、胰肠吻合时间、术后出血量、住院时间以及并发症的发生情况。结果:(1)手术平均时间(2.9±1.4)h,胰肠吻合平均时间(14±2.1)min,术后平均出血量(380±60)m L。所有患者经治疗后均治愈出院,住院时间平均(13.0±2.4)天。(2)术后并发症发生率为8例(23.5%),其中胰瘘2例(5.8%),为A级胰瘘;腹部感染3例(8.8%);腹腔出血2例(5.8%);胃排空延迟1例(2.9%)。无手术死亡者,无因严重并发症需要再次手术者。术后病理学诊断胰头癌18例,胆总管下癌8例,壶腹部癌5例,十二指肠乳头癌3例。结论:带蒂大网膜包埋的改良单层胰肠吻合能够减少术后胰瘘、出血、感染等并发症,提高手术成功率,值得临床进一步推广。     

24-Hour plasma secretin level and pancreatic secretion in dog

Plasma secretin concentrations were determined and duodenal pH was recorded continuously for a period of 24 hours after ingestion of a meal in 3 dogs with gastric cannula and duodenal cannula and in 4 dogs with pancreatic fistulae. The mean plasma secretin concentration increased significantly after a meal and it remained elevated for the first 12-hour period (peak at 30 min). Duodenal pH frequently decreased below 4.5 during the first 12-hour postprandial period, but it remained above 5.0 during the second 12 hours. Pancreatic secretion peaked during the first hour of meal ingestion and remained elevated until the end of 12 hours. The increased plasma secretin level in pancreatic fistula dog during the postprandial period was significantly greater than that of duodenal cannula dog, but the trends of increase in the secretin levels were quite identical. The present study indicates that: (1) plasma secretin concentration increases significantly within 30 min after a meal and remains increased during the first 12-hour period, (2) duodenal pH frequently decreased below 4.5 during the same 12 hours but more frequently during the first 6 hours, and (3) a significant increase in pancreatic water, HCO₃^? and protein occurred during the same time period.     

Localization of pancreatic polypeptide (PP)-like immunoreactivity in the pancreatic islets of some teleost fishes

Summary Immunocytochemical staining has revealed that the pancreatic islets of various teleost fishes contain a pancreatic polypeptide (PP)-like substance which cross-reacts with antibodies to mammalian and avian PP. The PP cells were frequently found at the periphery of the islets, as in mammals, and were of irregular shape.Dr. J.R. Kimmel kindly provided antibody to APP and the APP antigen, while anti-BPP and BPP were the gift of Dr. R.E. Chance.Blocks of pancreas from the pike were supplied by Dr. A. Thorpe, from the swordtail by Dr. C. Klein and from the garpike, catfish and eel by Dr. A. Epple. We are most grateful to all these people.This research was partly supported by a grant to one of us (GJP) from the National Institutes of Health, USA (Grant No. AM 17161) and by a grant from the Medical Research Council of Great Britain.     

白介素-17A在小鼠慢性胰腺炎中的作用研究

目的:研究白细胞介素-17A在小鼠慢性胰腺炎模型中的表达及其对小鼠星状细胞的影响。方法:建立雨蛙肽诱导的小鼠实验性慢性胰腺炎动物模型,利用实时荧光定量PCR、ELISA、免疫组化和Western-blot等手段检测白介素-17A在雨蛙肽诱导的小鼠慢性胰腺炎模型中的表达变化及免疫活性。用重组白介素-17A作用于小鼠胰腺星状细胞,检测其对星状细胞活化的作用,并进一步探究其对促胰腺纤维化炎症因子白介素-6、白介素-1β、TGF-β在mRNA水平的表达变化。结果:慢性胰腺炎胰腺组织中白介素-17A受体IL-17RA及IL-17RC mRNA水平的表达较正常胰腺明显升高,慢性胰腺炎小鼠胰腺组织中IL-17A蛋白水平较正常小鼠明显升高,CP小鼠血清中IL-17A蛋白水平(56.40±10.50 pg/L)较NC组(27.88±5.74pg/L)亦明显升高,IL-17A在正常胰腺组织中鲜有表达(8.9±2.72%),而在CP组织中呈强阳性表达(55.84±5.71%),其免疫活性主要定位于间质炎性细胞及导管样复合体中;重组白介素-17A可促进小鼠星状细胞活化,并直接诱导星状细胞表达白介素-6、白介素-1β以及TGF-β等促纤维化细胞因子。结论:白介素-17A在雨蛙肽诱导的小鼠慢性胰腺炎模型中表达上调,并可能通过诱导小鼠星状细胞表达促炎细胞因子白介素-6、白介素-1β和TGF-β,促进胰腺星状细胞活化以及胰腺纤维化。