喉癌细胞CD44+CD133+高致瘤亚群的生物学特性

目的 筛选喉癌细胞中的高致瘤亚群,探讨其作为肿瘤干细胞的生物学特性.方法 原代培养喉癌细胞,采用流式细胞仪分选CD44+、CD133+、CD44+CD133+、CD44+CD133-细胞,并分别以1×106、1×105、1×104、1×102个/只接种于裸小鼠左腋皮下,观察各亚群成瘤时间、成瘤率、平均瘤重及肿瘤体积,筛选出在极低细胞浓度下的高致瘤亚群.采用Boyden小室体外侵袭实验,检测各亚群细胞的侵袭能力.采用免疫细胞化学染色检测各亚群细胞中干细胞抗原-1(SCA-1)及整合素β1的表达.采用逆转录聚合酶链反应(RT-PCR)和Westem blot法,检测各亚群细胞中Bmi-1基因的表达.结果 CD44+CD133+细胞以1×103个/只接种于裸小鼠,可以成瘤.当各亚群细胞以1×106个/只接种于裸小鼠4周后,CD44+CD133+细胞接种组棵小鼠的肿瘤体积和重量分别为(7726.81±196.93)mm3和(5.51±0.12)g,均大于CD44+、CD44+CD133-及未分选细胞接种组(均P<0.05),而与CD133+细胞接种组裸小鼠的肿瘤体积和重量差异无统计学意义(P>0.05).CD44+CD133+细胞24 h的侵袭细胞数为83.62±1.61,显著高于其他各亚群喉癌细胞.CD44+CD133+细胞高表达整合素β1和SCA-1.Bmi-1 mRNA在CD44+CD133+细胞中的表达水平为0.951±0.112,显著高于CD44+CD133-细胞和未分选的喉癌细胞(0.532±0.214和0.268±0.193,均P<0.01);Bmi-1蛋白在CD133+和CD44+CD133+细胞中高表达,而在CD44+、CD44+CDi33-和未分选的喉癌细胞中仅有少量表达.结论 CD44+CD133+喉癌细胞具有高致瘤性及肿瘤干细胞的生物学特性,可能是喉癌恶性增殖的根源,并有望成为喉癌治疗的新靶点.     

胰腺癌干性细胞的分选及其生物学特性的初步鉴定

目的:应用流式细胞仪从人胰腺癌细胞系PANC-1中分选出肿瘤干性细胞,并对其生物学特性进行初步鉴定。方法:流式细胞仪分选出CD44+CD24+、CD44-CD24+、CD44+CD24-和CD44-CD24-4类细胞亚群;6MV X射线照射前后,DCFH-DA探针检查各亚群活性氧簇（reactive oxygen species,ROS）水平;将各亚群细胞接种于BALB/C-nu/nu裸小鼠,观察、比较成瘤率。结果:4个亚群细胞比例如下:CD44+CD24+（0.6±0.2）%、CD44+CD24-（89.3±2.6）%、CD44-CD24+（4.1±1.3）%和CD44-CD24-（6.0±1.7）%; 与其他亚群比较,CD44+CD24+干性细胞活性氧水平在X线照射后最低,平均荧光强度（MFI）显著低于其他3组细胞（P值均<0.01）。1×102个CD44+CD24+细胞接种于裸鼠,6周后成瘤（1/8）;接种1×104个CD44-CD24-细胞,12周后未成瘤。结论:分选出的各亚群中CD44+CD24+更具有胰腺癌干细胞特性,体内成瘤能力最强,其余依次为CD44+CD24-、CD44-CD24+、CD44-CD24-;CD44+CD24+细胞内ROS低水平,为进一步研究胰腺癌干性细胞ROS的基因调控奠定基础。     

胃癌细胞中CD44阳性细胞具有肿瘤干细胞特征

目的:在原位移植瘤模型上验证CD44+胃癌细胞的肿瘤干细胞特性.方法:选取MKN-45胃癌细胞株,通过流式细胞仪分选为CD44+和CD44-两组,以未分选的MKN-45胃癌细胞为对照.体外部分,通过MTT法和克隆形成实验验证CD44+胃癌细胞体外增殖能力,通过Transwell实验验证其侵袭力.体内部分,将上述细胞通过原位移植法接种至裸鼠,同等条件下饲养8周后处死裸鼠,检验其成瘤率;分离肝脏,检测肝转移瘤数目;H-E染色观察胃肿瘤和肝转移瘤形态;通过免疫荧光法检测两处肿瘤CD44+细胞数量.结果:CD44+胃癌细胞相比CD44‘胃癌细胞具有明显增强的细胞增殖力(P＜0.01)和侵袭力(P＜0.01),更容易成瘤且更容易发生转移(P＜0.05),但和MKN-45未分选组相比差异无统计学意义(P＞0.05).不论是在原发肿瘤还是转移瘤中,CD44+胃癌细胞均能产生CD44‘细胞,但后者不能产生CD44+细胞.结论:CD44+ MKN-45胃癌细胞相比CD44-胃癌细胞具备更强的增殖力和侵袭力、更容易成瘤和发生转移,符合肿瘤干细胞部分特征,值得进一步研究.     

CD44和CD24标记的宫颈癌细胞亚群特性

目的 考察Siha细胞系中的CD44^+/CD24⁺能否富集宫颈癌干细胞。方法 用流式细胞仪分选出CD44⁺/CD24⁺Siha细胞,用无血清悬浮培养观察成球能力、裸鼠移植瘤实验观察成瘤能力、透射电子显微镜观察辐射前后两组细胞形态变化,并通过Transwell侵袭实验比较细胞侵袭能力的差异。结果 耐放疗细胞中CD44^+/CD24⁺Siha细胞比例明显高于其在亲代Siha细胞中的比例;无血清培养CD44⁺/CD24⁺Siha细胞组可以形成致密且体积较大的细胞球,CD44^+/CD24⁺Siha细胞组致瘤时间早,成瘤率高;辐射后CD44⁺/CD24⁺Siha细胞较亲代Siha细胞更抗凋亡;CD44⁺/CD24⁺Siha细胞组的迁移细胞数明显高于亲代Siha细胞组,所有数据均具有统计学意义。结论 CD44⁺/CD24⁺Siha具备部分干细胞特性,CD44⁺/CD24⁺可能成为宫颈癌干细胞特异性表面标志物。     

CD44+CD24-/low乳腺癌干细胞分选鉴定及其多药耐药性研究

目的:观察MACS免疫磁珠法分选CD44+CD24-/low乳腺癌干细胞活性,并检测其与多药耐药的关系。方法:运用MACS免疫磁珠法从多药耐药乳腺癌细胞株MCF-7/ADR中分选CD44+CD24-/low乳腺癌干细胞,流式细胞术测定分选前后CD44+CD24-/low细胞比例,微球体培养法检测分选细胞自我更新能力,流式检测CD44+CD24-/low细胞表面P-糖蛋白(P-gp)表达水平,Real-time PCR检测多药耐药相关基因MDR1表达水平。结果:MACS免疫磁珠法分选后,CD44+CD24-/low细胞比例为93.85%,其成球能力明显强于non-CD44+CD24-/low细胞亚群。MCF-7/ADR细胞株和CD44+CD24-/low乳腺癌干细胞P-gp表达强度分别为101 177.10±2 171.86和114 906.70±2 560.19,P<0.05。CD44+CD24-/low乳腺癌干细胞MDR1基因表达水平为MCF-7/ADR细胞株的(1.07±0.02)倍,P<0.05。结论:经MACS免疫磁珠法分选所得CD44+CD24-/low细胞亚群有更强的自我更新能力,高表达P-gp蛋白和MDR1基因可能是引起乳腺癌多药耐药的重要原因。     

人胃癌CD90+干细胞可能影响胃癌的转移和患者的预后

目的： 分离并鉴定人胃癌细胞系SNU-5中的肿瘤干细胞,探讨人胃癌CD90+干细胞对胃癌转移和预后的影响。 方法： 无血清悬浮培养及PKH26染色确定SNU-5细胞系中是否存在肿瘤干细胞,流式细胞术分析SNU-5亲本及球体细胞中肿瘤干细胞标志物的表达,分选CD90+SNU-5细胞并进行体外生物学特征研究及SCID鼠致瘤实验。收集肿瘤医院腹部外科95例胃癌患者肿瘤病理标本,免疫组化方法检测胃癌组织中CD90的表达。 结果： SNU-5细胞无血清悬浮培养11 d后形成的细胞球体中存在单个PKH26阳性细胞。无血清悬浮培养可将CD90+SNU-5细胞富集6.1倍,且CD90可在球体细胞中与标示干细胞的PKH26共染。CD90+SNU-5细胞较CD90- SNU-5细胞和亲本SNU-5细胞具有更高的自我更新能力\[成球率（7.7±1.1）% vs (1.3±0.4)%、(1.8±0.3)%,均P<0.01\]和侵袭能力\[侵袭细胞数(283.3±30.2) vs (48.0±7.5)、(156.7±72)个,均P<0.01\]。CD90+SNU-5细胞在重症联合免疫缺陷（severe combined immune deficency,SCID）小鼠皮下接种2×102个细胞6周即可致瘤（1/6）,而接种2×104个CD90- SNU-5细胞10周才能致瘤（1/6）。95例胃癌患者组织中CD90的表达与胃癌的远处转移显著相关（P<0.01）,且CD90阳性胃癌患者的生存期明显短于CD90阴性的患者（P<0.01）。 结论： 人胃癌细胞系SNU-5中存在具有更强自我更新及侵袭能力的CD90+干细胞,人胃癌组织中CD90+干细胞数量与肿瘤的转移与患者生存期明显相关。     

无血清培养法分离并鉴定胰腺癌细胞系BxPC-3中肿瘤干细胞

[目的]从人胰腺癌细胞系BxPC-3中分离并鉴定胰腺癌干细胞。[方法]用无血清培养基培养人胰腺癌BxPC-3得到肿瘤细胞球。将肿瘤细胞球传代扩增,观察各传代后细胞成球能力;并用含血清培养基诱导促使其分化;蛋白印迹法测定肿瘤干细胞特异性转录因子OCT-4蛋白表达情况,并将肿瘤细胞球细胞植入NOD/SCID小鼠皮下,观察移植瘤的形成。[结果]在无血清培养基中,BxPC-3细胞能形成少量肿瘤细胞球,具有很强的自我更新能力,成球能力随着球体细胞传代次数的增加而增加。在含血清环境中,球体细胞逐渐分化而呈贴壁生长。肿瘤细胞球OCT-4蛋白表达明显高于BxPC-3贴壁细胞。1×104个球体细胞即能在NOD/SCID小鼠皮下成瘤。[结论]无血清培养能够有效的分离和扩增人胰腺癌细胞系BxPC-3的肿瘤干细胞。     

CD133~+胶质母细胞瘤细胞的分离与恶性行为特征

背景与目的:在恶性胶质瘤中存在一类恶性度极高的前体细胞,它们控制着肿瘤的生长与恶性演进,也是肿瘤复发的根源。本研究对胶质母细胞瘤进行肿瘤干细胞的分离与恶性行为特征分析,旨在验证胶质瘤干细胞的存在,并为未来该领域研究打下基础。方法:充分消化术中切除的胶质母细胞瘤组织块至单细胞悬液,流式细胞术检测CD133+肿瘤细胞百分率,免疫磁珠分选法分离CD133+和CD133-胶质母细胞瘤细胞;免疫荧光法检测两类细胞中巢蛋白(nestin)、胶质纤维酸性蛋白(GFAP)和神经元特异性烯醇化酶(NSE)的表达水平;Transwell双室培养体系检测两类瘤细胞的侵袭能力,血清依赖实验检测两类瘤细胞在低营养条件下的生存能力,软琼脂克隆形成实验检测瘤细胞的克隆形成能力;去胸腺小鼠腹股沟皮下接种瘤细胞,观察成瘤率。结果:流式细胞术检测CD133+肿瘤细胞百分率为(2.31±0.57)%。CD133+细胞高表达nestin,低表达GFAP和NSE;CD133-细胞则相反。与CD133-细胞比较,CD133+细胞具有更高的细胞侵袭能力、低营养耐受能力和克隆形成能力。CD133+细胞在小鼠体内成瘤率为87%(26/30),CD133-细胞为7%(2/30)。结论:CD133+胶质母细胞瘤细胞具有更高的恶性细胞表型,提示其具有高度研究价值。     

人肝癌PLC/PRF-5细胞中干细胞样细胞的分离及其特异性miRNAs的筛选

目的:分选及鉴定人肝癌PLC/PRF-5细胞中的肝癌干细胞样细胞,研究其microRNAs(miRNAs)表达谱。方法:以ABCG2为表面标志,免疫磁珠法分选、流式细胞术检测ABCG2+和ABCG2-PLC/PRF-5细胞,观察ABCG2+与ABCG2-PLC/PRF-5细胞的琼脂克隆形成能力和接种NOD/SCID小鼠的成瘤能力。应用miRNA芯片筛选ABCG2+和ABCG2-PLC/PRF-5细胞差异表达的miRNAs,real-time PCR验证部分差异表达的miRNAs。结果:免疫磁珠分选的ABCG2+PLC/PRF-5细胞纯度可达(84.20±4.52)%。ABCG2+PLC/PRF-5细胞比ABCG2-PLC/PRF-5细胞形成更多、更大的克隆集落(47.17±10.50 vs23.33±7.31,P<0.05);NOD/SCID小鼠接种1×104个ABCG2+PLC/PRF-5细胞即可成瘤,而ABCG2-PLC/PRF-5细胞至少需要5×105个才可成瘤;5×105个细胞时,ABCG2+PLC/PRF-5细胞组的肿瘤体积显著大于ABCG2-PLC/PRF-5细胞组[(3.73±1.19)cm3 vs(0.72±0.57)cm3,P<0.01]。ABCG2+PLC/PRF-5细胞和ABCG2-PLC/PRF-5细胞差异表达的miRNAs有20个:上调的13个,下调的7个;real-time PCR验证其中的hsa-miR-30a和hsa-miR-630的差异表达,其结果与miRNA芯片结果基本一致。结论:人肝癌细胞系PLC/PRF-5中ABCG2+细胞具有肿瘤干细胞的特性;ABCG2+和ABCG2-PLC/PRF-5细胞差异表达的miRNAs有20个,它们在肝癌发病中可能起重要的调控作用。     

LoVo细胞系中结肠癌干细胞样细胞的分离、培养及鉴定

摘 要　目的：从结肠癌LoVo细胞系中分离、鉴定具有CD44+/EPCAM high特异表型的结肠癌干细胞样细胞,观察其生物学行为,证实该细胞系中结肠癌干细胞样细胞的存在。方法：从普通血清培养的LoVo细胞系中以流式细胞仪分选具有CD44+/EPCAM high表型的细胞,接种于添加生长因子的无血清培养基中,观察其增殖过程,继而诱导分化。MTT法、流式细胞术检测CD44+/EPCAM high、EPCAM low和未分选LoVo细胞的增殖能力及细胞周期分布。3种细胞接种裸鼠,比较不同细胞的成瘤率;免疫荧光技术检测小鼠次代CD44+/EPCAM high细胞中 CD44/EPCAM的表达。结果：LoVo细胞中有17.4%的CD44+/EPCAM high细胞,并能在添加生长因子的无血清培养基中呈细胞球样生长,且可连续传代;在血清的诱导下,呈贴壁分化生长,其形态与未分选LoVo细胞无差别。CD44+/EPCAM high细胞增殖能力高于EPCAM low细胞及未分选LoVo细胞,且细胞周期多集中在G0/G1期。以500个CD44+/EPCAM high细胞接种裸鼠成瘤率为90%（9/10）,而1×104个EPCAM low细胞成瘤率为0（0/10)。小鼠移植瘤中次代CD44+/EPCAM high细胞仍能少量表达CD44和EPCAM。结论：LoVo细胞中存在CD44+/EPCAM high结肠癌干细胞样细胞,CD44+/EPCAM high可用于结肠癌肿瘤干细胞的深入研究。     

Animal models of exocrine pancreatic carcinogenesis

In order to understand the evolution, histogenesis, and biological behaviour of exocrine pancreatic carcinoma, some reproducible experimental models have been developed in certain rodent species. To date, more than 16 chemicals, many of them structurally unrelated, have been shown to induce pancreatic tumors. Although some of these chemicals appear species specific in their effect on the pancreas, others have been shown to be capable of inducing pancreatic tumors in more than one species. In hamsters, the administration of diisopropylnitrosamine or its oxidized metabolites leads to the development of ductal adenocarcinomas that histologically resemble human pancreatic carcinomas. The histogenesis of the ductal type of adenocarcinoma in hamsters is complex, and appears to involve both the duct cells and dedifferentiated acinar cells. All pancreatic tumors in rats develop from acinar cells showing variable degrees of differentiation, regardless of the type of carcinogen used. The type of pancreatic lesions that develop in mice are also of acinar cell origin. In guinea pigs the tumors are adenocarcinomas of the ductal type and are shown to be derived from dedifferentiated acinar cells that have undergone duct-like transformation. Irrespective of the type of tumor that develops in these experimental animals, all of these models can be successfully used to evaluate the various modifying (risk) factors and biological behaviour of these neoplasms.     

Increased glyceraldehyde-3-phosphate dehydrogenase gene expression in human pancreatic adenocarcinoma

To identify and characterize genes, the products of which play a role in pancreatic adenocarcinoma, we constructed a complementary DNA (cDNA) library using mRNA from the pancreatic adenocarcinoma cell line HPAF, grown as a nude mouse tumor. Through differential screening, we identified a cDNA clone, pII5B, that is homologous to an mRNA expressed at significantly higher levels in HPAF cells than in normal human pancreas. The pII5B cDNA was homologous to the 3'-untranslated region of glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12)mRNA. Partial sequencing of several HPAF tumor GAPDH cDNA clones revealed no significant differences from previously published GAPDH cDNA sequences. Increased levels of GAPDH mRNA, relative to actin mRNA levels, were found in six pancreatic adenocarcinoma cell lines and two nude mouse tumors, when compared to normal pancreas. Enolase and glucose transporter mRNA levels were also increased in HPAF cells and nude mouse tumor, suggesting a general increase in expression of genes associated with glycolysis in pancreatic adenocarcinoma. Levels of GAPDH protein were elevated in nude mouse tumors and fresh human pancreatic adenocarcinomas compared to normal pancreas. High GAPDH levels may be characteristic of human adenocarcinomas, since colon adenocarcinomas also exhibited high levels of GAPDH compared to normal colon.     

Human pancreatic ribonuclease 1: expression and distribution in pancreatic adenocarcinoma

BACKGROUND: Human pancreatic ribonuclease (RNase 1) is a pancreatic enzyme that is present at high levels in the serum of most patients with pancreatic adenocarcinoma. For this reason, the authors studied its patterns of expression at the single-cell level in pancreatic adenocarcinoma tissues by immunohistochemical analysis and in situ hybridization (ISH). METHODS: Immunohistochemical analysis with polyclonal antibodies against RNase 1 and by ISH with digoxigenin-labeled RNase 1 probe were used to detect RNase 1 in the neoplastic cells of ductal type pancreatic adenocarcinomas. RESULTS: Fifteen of 18 carcinoma samples were positive for RNase 1, demonstrating that the expression of ribonuclease that the authors observed previously in human pancreatic adenocarcinoma cell lines was not an artifact of cell culture. The authors also found RNase 1 in some of the metaplastic ducts and atrophic islets in 4 of 6 chronic pancreatitis samples, and they observed RNase 1 immunostaining in hyperplastic ducts adjacent to one of the well-differentiated adenocarcinomas. CONCLUSIONS: The expression levels of RNase 1 by tumor cells from pancreatic adenocarcinomas are consistent with the high RNase 1 levels found in the serum of most patients with pancreatic adenocarcinoma. This expression of RNase 1, which is an acinar protein, demonstrates that the patterns of gene expression in pancreatic adenocarcinoma are distinct from those of normal pancreatic duct cells. Conversely, RNase 1 expression levels in altered ductal cells from some chronic pancreatitis tissues and hyperplastic ducts from carcinoma tissues suggest that abnormal expression levels may be an early event in pancreatic tumorigenesis.     

Fas (CD95/APO-1) and Fas ligand expression in normal pancreas and pancreatic tumors. Implications for immune privilege and immune escape

BACKGROUND: Fas (CD95/APO-1) and Fas ligand (FasL) play key roles in immunologic homeostasis and immune privilege and may regulate normal cell turnover. Earlier studies had suggested that FasL-positive pancreatic carcinoma cell lines can induce apoptosis in T cells, thereby evading host immune surveillance. In the current study the authors have characterized the expression of Fas and FasL in the normal pancreas and in pancreatic neoplasia. METHODS: Pancreatic resection specimens with ductal-type adenocarcinoma or intraductal dysplasia (n = 41), nonductal pancreatic neoplasms (n = 5), and chronic pancreatitis (n = 4) were examined for Fas and FasL expression by immunohistochemistry. The results in invasive adenocarcinoma were compared to those for benign ducts and intraductal dysplasia, and correlated with clinicopathologic features of the tumors and with patient survival. RESULTS: Fas was expressed in the normal pancreatic ducts and in intraductal dysplasia in a mixed membrane/cytoplasmic pattern. In all cases of invasive ductal-type adenocarcinoma, membranous Fas could not be detected; cytoplasmic Fas staining was reduced or completely lost. Loss of Fas expression in pancreatic ductal-type adenocarcinomas significantly correlated with poorer differentiation and extrapancreatic spread of the tumors and was associated with a shorter overall survival. FasL expression was present in the normal pancreatic ducts as well as in islet cells and was maintained in all pancreatic tumors. CONCLUSIONS: These results implicate the Fas pathway in the regulation of physiologic cell turnover and immune privilege in the normal pancreas and indicate that loss of Fas expression is correlated with malignant transformation and biologic aggressiveness in pancreatic adenocarcinomas. This may represent a mechanism by which pancreatic tumor cells become resistant to apoptosis and escape immune surveillance in vivo.     

Aberrant nuclear accumulation of glycogen synthase kinase-3beta in human pancreatic cancer: association with kinase activity and tumor dedifferentiation.

PURPOSE: We have shown recently that glycogen synthase kinase-3 (GSK-3) beta regulates nuclear factor-kappaB (NF-kappaB)-mediated pancreatic cancer cell survival and proliferation in vitro. Our objective was to determine the localization of GSK-3beta in pancreatic cancer cells and assess the antitumor effect of GSK-3 inhibition in vivo to improve our understanding of the mechanism by which GSK-3beta affects NF-kappaB activity in pancreatic cancer. EXPERIMENTAL DESIGN: Immunohistochemistry and cytosolic/nuclear fractionation were done to determine the localization of GSK-3beta in human pancreatic tumors. We studied the effect of GSK-3 inhibition on tumor growth, cancer cell proliferation, and survival in established CAPAN2 tumor xenografts using a tumor regrowth delay assay, Western blotting, bromodeoxyuridine incorporation, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. RESULTS: We found nuclear accumulation of GSK-3beta in pancreatic cancer cell lines and in 62 of 122 (51%) human pancreatic adenocarcinomas. GSK-3beta nuclear accumulation is significantly correlated with human pancreatic cancer dedifferentiation. We have found that active GSK-3beta can accumulate in the nucleus of pancreatic cancer cells and that inhibition of GSK-3 kinase activity represses its nuclear accumulation via proteasomal degradation within the nucleus. Lastly, we have found that inhibition of GSK-3 arrests pancreatic tumor growth in vivo and decreases NF-kappaB-mediated pancreatic cancer cell survival and proliferation in established tumor xenografts. CONCLUSIONS: Our results show the antitumor effect of GSK-3 inhibition in vivo, identify GSK-3beta nuclear accumulation as a hallmark of poorly differentiated pancreatic adenocarcinoma, and provide new insight into the mechanism by which GSK-3beta regulates NF-kappaB activity in pancreatic cancer.     

Establishment of tumor cell culture (ILA) derived from hamster pancreatic islets treated with BOP

ILA cells were established from tumors induced by the pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP) in hamster islets. The proliferation, morphology, karyotype, immunoreactivity with certain antibodies and growth factor secretion of these tumor cells were compared with the same parameters in tumor cells induced by BOP in hamster ductal cells (TAKA-1-BOP) established in a previous study. Minor differences were found in the morphology and ultrastructure of the 2 cell lines. Contrary to TAKA-1-BOP cells, ILA cells did not express cytokeratins 8.13, 13 or 18 but did express DU-PAN-2 and TAG-72, 2 known human pancreatic cancer–associated antigens. No endocrine cell markers were expressed. A significant difference also was found in the chromosomal pattern in that there were more abnormalities and marker chromosomes in ILA cells than in TAKA-1-BOP cells and the Y or X chromosomes were missing in ILA cells. ILA cells produced TGF-α, IGF-1, bombesin and gastrin and expressed specific binding sites for hEGF. TGF-α secretion from ILA cells was much greater than that from TAKA-1-BOP cells. Our results indicate that pancreatic cancer cells grown in vitro are not a single clone. We conclude that there are some genetic and biological differences between tumors arising from pancreatic duct and islets and that pancreatic ductal adenocarcinomas originating from islets have a profound malignant potential. Int. J. Cancer 78:636–641, 1998. © 1998 Wiley-Liss, Inc.     

Expression of neutral endopeptidase (NEP/CD10) on pancreatic tumor cell lines, pancreatitis and pancreatic tumor tissues

Neutral endopeptidase (NEP/CD10) is a cell surface zinc metalloprotease cleaving peptide bounds on the amino terminus of hydrophobic amino acids and inactivating multiple physiologically active peptides. Loss or decrease in NEP/CD10 expression have been reported in many types of malignancies, but the role of NEP/CD10 in pancreatic carcinoma has not yet been identified. Using real-time RT-PCR, flow cytometry as well as immunohistochemistry, NEP/CD10 expression was quantified in both pancreatic carcinoma cell lines and in tumor specimens obtained from patients with primary pancreatic carcinomas. Three out of 8 pancreatic carcinoma cell lines exhibit heterogeneous NEP/CD10 expression levels: PATU-8988T expressed the highest NEP/CD10 levels, whereas HUP-T4 and HUP-T3 cells showed a moderate to low NEP/CD10 expression. NEP/CD10 immunoreactivity was found in 6 of 24 pancreatic ductal adenocarcinomas, but also in 3 of 6 tissues of patients with chronic pancreatitis. NEP/CD10 expression in pancreatic tumor lesions and cell lines was not associated with tumor grading and staging. Treatment of PATU-8988T cells with the histone deacetylase inhibitors sodium butyrate and valproic acid induced an increase of NEP/CD10 expression. This was accompanied by a reduced cell proliferation rate of PATU-8988T cells, which was increased by the addition of the enzyme activity inhibitors phosphoramidon and thiorphan. Thus, NEP/CD10 is differentially expressed in pancreatic tumors and might be involved in the proliferative activity of pancreatic cancer cells. However, further studies are needed to provide more detailed information of the role of NEP/CD10 under physiological and pathophysiological conditions of the pancreas.     

Down-regulation of CD9 expression during prostate carcinoma progression is associated with CD9 mRNA modifications.

PURPOSE: Cluster-of-differentiation antigen 9 (CD9) protein, a member of the tetraspanin family, has been implicated in carcinogenesis of various human tumors. Although decreased expression of the CD82 tetraspanin protein, a close CD9 relative, is associated with prostate cancer progression, CD9 expression has not been analyzed in this malignancy. EXPERIMENTAL DESIGN: CD9 expression in human prostatic adenocarcinoma was analyzed by immunohistochemistry on 167 primary tumors and 88 lymph node or bone metastases. CD9 cDNA was sequenced from two human prostate cancer cell lines, prostatic adenocarcinoma, high-grade prostatic intraepithelial neoplasia (PIN), and normal prostatic tissues. RESULTS: Although CD9 was detected in the epithelium of normal prostatic tissues, reduced or loss of CD9 expression within neoplastic cells was observed in 24% of 107 clinically localized primary adenocarcinomas, 85% of 60 clinically advanced primary adenocarcinomas, 85% of 65 lymph node metastases, and 65% of 23 bone metastases. Difference in CD9 expression between clinically localized and advanced diseases was highly significant (P < 1 x 10(-7)). Whereas there was no alteration of CD9 cDNA in normal tissues, all PC-3-derived cell lines, one PIN, and four prostatic adenocarcinomas harbored deletions in their CD9 cDNAs. Recurring CD9 point mutations were also found in PC-3M-LN4 cells, one PIN, and seven prostatic adenocarcinomas. CONCLUSIONS: CD9 expression is significantly reduced and even lost during prostate cancer progression. Moreover, deletions and mutations of the CD9 mRNA may be associated with loss of protein expression observed in tumor cells. Our data suggest that CD9 inactivation may play an important role in prostate cancer progression.