Notch2 is required for progression of pancreatic intraepithelial neoplasia and development of pancreatic ductal adenocarcinoma

Pancreatic cancer is one of the most fatal malignancies lacking effective therapies. Notch signaling is a key regulator of cell fate specification and pancreatic cancer development; however, the role of individual Notch receptors and downstream signaling is largely unknown. Here, we show that Notch2 is predominantly expressed in ductal cells and pancreatic intraepithelial neoplasia (PanIN) lesions. Using genetically engineered mice, we demonstrate the effect of conditional Notch receptor ablation in Kras^G12D-driven pancreatic carcinogenesis. Deficiency of Notch2 but not Notch1 stops PanIN progression, prolongs survival, and leads to a phenotypical switch toward anaplastic pancreatic cancer with epithelial–mesenchymal transition. By expression profiling, we identified increased Myc signaling regulated by Notch2 during tumor development, placing Notch2 as a central regulator of PanIN progression and malignant transformation. Our study supports the concept of distinctive roles of individual Notch receptors in cancer development.     

Spontaneous induction of murine pancreatic intraepithelial neoplasia (mPanIN) by acinar cell targeting of oncogenic Kras in adult mice

Pancreatic ductal adenocarcinoma (PDAC) is believed to arise through a multistep model comprised of putative precursor lesions known as pancreatic intraepithelial neoplasia (PanIN). Recent genetically engineered mouse models of PDAC demonstrate a comparable morphologic spectrum of murine PanIN (mPanIN) lesions. The histogenesis of PanIN and PDAC in both mice and men remains controversial. The most faithful genetic models activate an oncogenic Kras^G12D knockin allele within the pdx1- or ptf1a/p48-expression domain of the entire pancreatic anlage during development, thus obscuring the putative cell(s)-of-origin from which subsequent mPanIN lesions arise. In our study, activation of this knockin Kras^G12D allele in the Elastase- and Mist1-expressing mature acinar compartment of adult mice resulted in the spontaneous induction of mPanIN lesions of all histological grades, although invasive carcinomas per se were not seen. We observed no requirement for concomitant chronic exocrine injury in the induction of mPanIN lesions from the mature acinar cell compartment. The acinar cell derivation of the mPanINs was established through lineage tracing in reporter mice, and by microdissection of lesional tissue demonstrating Cre-mediated recombination events. In contrast to the uniformly penetrant mPanIN phenotype observed following developmental activation of Kras^G12D in the Pdx1-expressing progenitor cells, the Pdx1-expressing population in the mature pancreas (predominantly islet β cells) appears to be relatively resistant to the effects of oncogenic Kras. We conclude that in the appropriate genetic context, the differentiated acinar cell compartment in adult mice retains its susceptibility for spontaneous transformation into mPanIN lesions, a finding with potential relevance vis-à-vis the origins of PDAC.     

Matrix metalloproteinase 7 controls pancreatic acinar cell transdifferentiation by activating the Notch signaling pathway

Acinar-to-ductal metaplasia in the pancreas is associated with an increased risk for tumorigenesis. Molecular dissection of this process in vitro has shown that primary acinar cells, in response to EGF receptor ligands, can transdifferentiate into duct-like epithelia, passing through a nestin-positive intermediate, in a Notch pathway-dependent manner. Here, we show that in vitro acinar transdifferentiation depends on matrix metalloproteinase 7 (MMP-7), a proteinase expressed in most metaplastic epithelia in vivo. MMP-7 was found to be required for Notch activation, which leads to dedifferentiation of acinar cells to the nestin-positive transitional cell. Besides being necessary for acinar transdifferentiation, it was found that MMP-7 activity was sufficient to induce the process, indicating that molecular signals capable of initiating MMP-7 expression also have the potential to induce formation of metaplastic epithelia in the pancreas.     

Progression to pancreatic ductal adenocarcinoma from pancreatic intraepithelial neoplasia: Results of a simulation model

Objectives

To gain insight into the natural history and carcinogenesis pathway of Pancreatic Intraepithelial Neoplasia (PanIN) lesions by building a calibrated simulation model of PanIN progression to pancreatic ductal adenocarcinoma (PDAC)

胰腺导管腺癌、慢性胰腺炎及正常胰腺组织中胰腺上皮内瘤变的比较研究

目的探讨胰腺导管腺癌、慢性胰腺炎和正常胰腺组织中各级别PanIN的发生率以及与临床病理学参数间的关系.方法回顾性研究长海医院2001年1月～ 2003年12月间外科切除和同期尸检获得的250例胰腺标本中PanIN的发生情况,并联系临床病理指标进行相关分析.结果 250例胰腺标本中,有156例存在PanIN病变,发生率62.4%.其中,胰腺导管腺癌、慢性胰腺炎和正常胰腺组织中PanIN的发生率分别为75.6%、46.0%和30.0%,胰腺导管腺癌PanIN发生率明显高于慢性胰腺炎及正常胰腺组织(P < 0.01);慢性胰腺炎中高级别PanIN发生率明显高于正常胰腺组织(P < 0.05).PanIN-3仅在胰腺导管腺癌和慢性胰腺炎中见到.胰腺导管腺癌中,有烟酒嗜好和(或)糖尿病者高级别PanIN的发生率53.7%,明显高于对照组29.4%(P < 0.01).PanIN的发生率以61 ～ 70岁年龄组为最高.结论胰腺导管腺癌、慢性胰腺炎和正常胰腺组织中PanIN的发生率逐渐增加,程度逐渐加重,支持胰腺癌发生的分子模型.     

胰腺导管腺癌、慢性胰腺炎及正常胰腺组织中胰腺上皮内瘤变的比较研究

目的探讨胰腺导管腺癌、慢性胰腺炎和正常胰腺组织中各级别PanIN的发生率以及与临床病理学参数间的关系。方法回顾性研究长海医院2001年1月-2003年12月间外科切除和同期尸检获得的250例胰腺标本中PanIN的发生情况,并联系临床病理指标进行相关分析。结果250例胰腺标本中,有156例存在PanIN病变,发生率62.4％。其中,胰腺导管腺癌、慢性胰腺炎和正常胰腺组织中PanIN的发生率分别为75.6％、46.0％和30.0％,胰腺导管腺癌PanIN发生率明显高于慢性胰腺炎及正常胰腺组织(P<0.01);慢性胰腺炎中高级别PanIN发生率明显高于正常胰腺组织(P<0.05)。PanIN-3仅在胰腺导管腺癌和慢性胰腺炎中见到。胰腺导管腺癌中,有烟酒嗜好和(或)糖尿病者高级别PanIN的发生率53.7％,明显高于对照组29.4％(P<0.01)。PanIN的发生率以61-70岁年龄组为最高。结论胰腺导管腺癌、慢性胰腺炎和正常胰腺组织中PanIN的发生率逐渐增加,程度逐渐加重,支持胰腺癌发生的分子模型。     

TGF-β/Smads信号通路相关蛋白在胰腺上皮内瘤变和胰腺癌组织中的表达

目的探讨转化生长因子(TGF)-β/Smads信号转导通路中Smads相关蛋白、TGF-β1及其Ⅰ、Ⅱ型受体在胰腺上皮内瘤变(PanIN)和胰腺癌组织中表达的意义.方法用EnVision和SP免疫组化技术检测266灶不同级别PanINs和121例胰腺癌组织中Smads相关蛋白、TGF-β1及其Ⅰ、Ⅱ型受体的表达并联系临床病理学指标进行相关分析.结果高级别PanINs病灶Smad4表达率(60.6%,20/33)显著低于低级别PanINs Smad4表达率(79.8%,186/233)(P<0.05);而高级别PanINs中Smad7、TGF-β1、TGF-βRⅡ表达率明显高于低级别PanINs(P<0.05).胰腺癌组织中,Smad4蛋白表达率在淋巴结转移组和神经受累组显著低于各自对照组(P<0.05);Smad7、TGF-β1及其Ⅰ、Ⅱ型受体的表达率在淋巴结转移组和神经受累组则分别显著高于各自对照组(P<0.05).胰腺上皮内瘤变和胰腺癌组织中Smad2、4、7蛋白,TGF-β1及其Ⅰ、Ⅱ型受体表达率的差异具有非常显著性(P<0.01).结论从低级别PanINs到高级别PanINs再到胰腺癌中,Smad4蛋白表达率逐渐降低,而Smad7、TGF-β1及其Ⅰ、Ⅱ型受体表达率逐渐升高,支持胰腺癌形成的分子模型.     

胃黏膜肠上皮化生、胃上皮内瘤变与胃癌的组织发生

胃癌是严重危害人民健康的疾病之一,其发病机制尚不明确.胃癌的发生常在癌变之前经历相当漫长的演变过程,即由正常胃黏膜转变成胃癌前病变,部分再发展成胃癌.目前公认,胃黏膜异型增生和肠上皮化生是胃癌前病变.鉴于胃癌的高度恶性,且其病因发病机制尚未完全阐明,实施针对病因的一级预防比较困难.本文就胃上皮内瘤变、异型增生和肠化生的定义和分类,幽门螺杆菌感染、萎缩性胃炎、肠化生与胃癌发生的相关性等问题进行综述,旨在提高对胃癌前病变的认识水平,以便于临床医师对胃癌前病变、特别是萎缩性胃炎进行密切的监测及予以及时有效的干预.     

Growing pancreatic acinar cells (postpancreatitis and fetal) express a ductal antigen

Monoclonal antibodies specific for luminal plasma membranes of acinar and duct cells of the exocrine pancreas were used to investigate changes in antigen expression during regeneration of the pancreas after acute pancreatitis and during fetal pancreatic development in mice. During regeneration after acute pancreatitis induced by supramaximal injections of cerulein or by a choline-deficient, ethionine-supplemented diet, morphologically identifiable acinar cells expressed the ductal antigen on their luminal surface, but at a lower level than this antigen is expressed on duct cells. As the pancreas regenerated, the ductal antigen was lost from acinar cells and was found only on duct cells. Characteristic tubular complexes formed in both pancreatitis models and were positive for the acinar antigen, demonstrating their acinar origin. In fetal pancreas, acinar cells between prenatal days 3 through 1, when zymogen granules were already abundant, expressed the duct-cell antigen on their luminal surface. By birth duct antigen was mostly present on ducts with only occasional label on acinar cells. The presence of a ductal antigen on acinar cells is associated with acinar-cell growth during regeneration and during fetal development and may reflect a less differentiated state.     

改善酒精性胰腺腺泡细胞分泌功能不足的分子靶点探讨

[目的]探讨改善酒精性胰腺腺泡细胞分泌功能不足的分子靶点。[方法]1将48只大鼠随机分为4组,每组12只。饮酒6个月组(A1组),饮酒6个月对照组(A2组),戒酒3个月组(B1)组,戒酒3个月对照组(B2组);2苏木精-伊红染色和电镜观察戒酒后酒精性胰腺腺泡细胞的形态变化;3采用酶法测定胰腺组织的淀粉酶、脂肪酶含量;4免疫荧光法和免疫印迹检测CCK-A受体在胰腺的表达;5放射免疫分析法(RIA)测定胰腺和小肠组织中的胆囊收缩素(CCK)含量;6用比色法测定血浆和小肠食糜中游离脂肪酸及食糜中三酰甘油含量。[结果]与A2组大鼠相比,A1组电镜下见腺泡细胞超微结构出现了明显的变化,如线粒体水肿,髓样小体形成,粗面内质网扩张,酶原颗粒减少,易见脂滴;A1组大鼠饮酒6个月后胰腺淀粉酶、脂肪酶水平、小肠和胰腺的CCK水平均较A2组显著下降。B1组胰腺组织学及腺泡细胞超微结构的病变较B2组并无明显改善,其胰腺淀粉酶、脂肪酶水平、小肠和胰腺的CCK水平仍低于B2组。[结论]慢性酒精对胰腺腺泡细胞结构及功能的损伤在戒酒后仍不能自然恢复;补充消化酶,可改善其外分泌功能。     

High-grade pancreatic intraepithelial lesions: prevalence and implications in pancreatic neoplasia

BACKGROUND: High-grade pancreatic intraepithelial neoplasia(Pan IN-3), a precursor of pancreatic ductal adenocarcinoma(PDAC), is not universally detected in resected pancreatic neoplasms. We sought to determine the prevalence and prognostic relevance of Pan IN-3 lesions in primary surgical resections of PDACs and intraductal papillary mucinous neoplasms(IPMNs).METHODS: A retrospective review of a tertiary care center pathology database(1/2000-6/2014) was performed. Demographics, imaging, pathology, disease-recurrence, and survival data were reviewed.RESULTS: A total of 458 patients who underwent primary pancreatic resection were included. "Pan IN-3" lesions were found in 74(16.2%) patients who either had PDAC(n=67) or main duct(MD)-IPMN(n=7). Among IPMN-MDs, Pan IN-3 lesions were exclusively found in those with pathological evidence of chronic pancreatitis. For PDACs, the median overall survival(OS) for pancreata with Pan IN-3 lesions was significantly better than those without(OS 1.12 years, interquartile range [IQR] 0.72, 2.05 years vs OS 0.86 years, IQR 0.64,1.60 years respectively; P=0.04). Multivariate Cox regression analysis demonstrated that the presence of Pan IN-3 lesions was associated with a reduced risk of death(HR=0.43; 95% CI: 0.23-0.82; P=0.01).CONCLUSIONS: Following primary resection of pancreatic adenocarcinoma, the lower survival observed in patients without Pan IN-3 lesions might suggest a state of complete or accelerated transformation. Further investigations are necessary to validate these findings that might impact disease prognosis and management.     

E-钙黏附素和β-连环素在胰腺上皮内瘤变和胰腺癌组织中的表达

目的:探讨胰腺上皮内瘤变PanIN和胰腺癌组织中E-钙黏附素(E-Cad)和β-连环素(β-Cat)异常表达的意义.方法:回顾性研究长海医院2001-01/2003-12间外科切除和同期尸检的156例胰腺标本,并构建了组织芯片,其中含有129灶PanIN-1A,104灶PanIN-1B,22灶PanIN-2,11灶PanIN-3和121例导管腺癌和相应癌旁组织.用EnVision免疫组化技术检测上述病变组织中E-Cad和β-Cat的表达变化,并结合临床病理资料进行相关分析.结果:导管腺癌中E-Cad异常表达率明显高于PanINs和正常导管(64.5%,32.3%,0%),且与胰腺癌的分化程度、淋巴结转移和神经浸润密切相关(P＜0.05).PanINs和导管腺癌中E-Cad胞质表达较正常导管明显增加.β-Cat的异常表达与胰腺癌淋巴结转移和神经浸润有明显相关性(P＜0.05).高级别PanINs和导管腺癌中β-Cat胞质和胞核的表达率明显高于低级别PanINs和正常导管(P＜0.05).PanINs和导管腺癌中E-Cad和β-Cat表达间呈正相关性(P＜0.01,P＜0.05).结论:胰腺癌和PanINs中E-Cad和β-Cat的异常改变提示他们不仅与胰腺癌的生物学行为和预后有关,而且也参与了胰腺癌的发生.     

胰腺腺管内上皮瘤的研究进展

胰腺癌的早期诊断与综合治疗目前缺乏有效的措施，80％的胰腺癌在诊断时已丧失手术机会，5年生存率仅为0．4％～4％。胰腺癌生存时间的延长取决于早发现、早治疗。故充分认识胰腺癌的癌前病变一胰晾腺管内上皮瘤（PanlN），了解其病理分级及与之相关的各级分子生物学水平的改变，讨论PanlN红胰腺癌形成中的作用，对胰腺癌的早期诊断及综合治疗有重要意义。     

Simvastatin delay progression of pancreatic intraepithelial neoplasia and cancer formation in a genetically engineered mouse model of pancreatic cancer

Background and aimsPancreatic cancer is among the most dismal of human malignancies. There are no chemopreventive strategies for pancreatic cancer or its precursor lesions, pancreatic intraepithelial neoplasia (PanINs). Recent evidence suggests that statins have potential chemopreventive abilities. In this study, we used a genetically engineered mouse model of pancreatic cancer to evaluate the chemopreventive potential of this drug.MethodsSimvastatin was injected i.p. in LsL-Kras^G12D; Pdx1-Cre or LsL-Kras^G12D;LsL-Trp53^R172H;Pdx1-Cre mice. After five months, animals were sacrificed. The effect of simvastatin was evaluated by histopathological analyses, immunostaining, and real-time PCR.ResultsAfter five months of treatment, simvastatin was able to significantly delay progression of mPanINs in LsL-Kras^G12D; Pdx1-Cre mice. Furthermore, formation of invasive pancreatic cancer in LsL-Kras^G12D; LsL-Trp53^R172H; Pdx1-Cre transgenic mice was partially inhibited by simvastatin. Invasive murine pancreatic cancer was identified in 9 of 12 (75%) LsL-Kras^G12D; LsL-Trp53^R172H;Pdx1-Cre untreated control mice. In contrast, transgenic mice treated with Simvastatin, only 4 out of 10 (40%, p = 0.004) developed murine pancreatic cancer during the study. Using real-time PCR we found a significant up-regulation of Hmgcr as sign of blocking HMG-CoA reductase, a key enzyme in the cholesterol biosynthesis. This shows our ability to achieve effective pharmacologic levels of simvastatin during pancreatic cancer formation in vivo.ConclusionUsing a transgenic mouse model that recapitulates human pancreatic cancer, this study provides first evidence that simvastatin is an effective chemopreventive agent by delaying the progression of PanINs and partially inhibit the formation of murine pancreatic cancer.     

Cryopreserved mouse pancreatic acinar cells from long-term explant outgrowth cultures maintain their secretory phenotype after thawing

Background/objectivesWe recently reported an explant outgrowth culture method for obtaining functionally competent mouse pancreatic acinar cells for long-term in vitro purposes. The aim of the present study was to explore the possibility of cryostoring these cells without loss of functional differentiation.MethodsAcinar cells prepared by the explant outgrowth method were cryopreserved using a DMSO-based protocol and stored in liquid nitrogen for 4 weeks. The following characteristics were compared in cryopreserved and parallel non-frozen cell preparations: cell viability and recovery, amylase content in viable cells before culture, basal and stimulated amylase release in culture and the ability of the cells to form glandular structures in Matrigel.ResultsImmediate post-thaw viability of the cells was similar to that of freshly isolated cells. Approximately 53% of viable cells frozen were recovered after thawing. Intracellular amylase content was identical in frozen and non-frozen cells. Cryopreserved cells maintained their ability to secrete amylase and to respond to caerulein stimulation in 4-day secondary cultures. They also were observed to form amylase-expressing glandular structures in three-dimensional cultures in Matrigel in a similar manner as non-frozen cells.ConclusionsThis study shows that pancreatic acinar cells can be cryopreserved for long-term storage in liquid nitrogen without dedifferentiation. Successful cryopreservation helps to refine the experimental use of primary acinar cells by enabling their banking for on-demand utilization.     

Proteomic analysis of pancreatic intraepithelial neoplasia and pancreatic carcinoma in rat models

AIM:To detect the proteomic variabilities of pancreatic intraepithelial neoplasia(PanIN)and pancreatic carcinoma(PC)induced by 7,12-dimethylbenzanthracene(DMBA) in rat models and to identify potential biomarkers.METHODS:Sixty adult male Sprague Dawley rats were randomized into three groups.The rats had DMBA implanted into their pancreas for one(n=20)or two months(n=20)or assigned to the normal group(n =20).The rats were killed after one or two months,and were evaluated histopathologically.Three tissue sampl...     

Comparative analysis of a human pancreatic undifferentiated cell line (MIA PaCa-2) to acinar and ductal cells

Pancreatic ductal cell secretion has not been well characterized due to the difficulty in obtaining sufficient quantities of purified ductal cells. To determine if the MIA PaCa-2 cell line would provide a useful model for in vitro studies of pancreatic ductal cell secretion, the present study was designed to characterize these cells in greater detail. In this investigation, the human pancreatic undifferentiated cell line, MIA PaCa-2, was compared with PANC-1 cells (a human ductal cell line previously characterized), isolated rat and human ducts, acinar cells, and nonpancreatic cell lines. The results indicate that while the morphology of the MIA PaCa-2 cell line is nonpolarized and generally atypical of either ductal or acinar cells, the cell line has retained certain biochemical similarities to ductal cells. Additional morphological studies indicated (a) the presence of intermediate filaments characteristic of epithelial cells, (b) the absence of zymogen granules, and (c) an apparent basolateral plasma membrane localization of Na+, K+-ATPase. Similar to ductal cells, biochemical analyses indicated (a) the presence of Na+, K+-ATPase based on [3H]-ouabain binding assays, (b) high levels of carbonic anhydrase, (c) low levels of gamma-glutamyl transpeptidase, (d) nondetectable levels of amylase, and (e) protein composition and protein synthetic patterns comparable to PANC-1 cells. Finally, as with PANC-1 cells and isolated rat and human ducts, the major sulfated secretory product of MIA PaCa-2 cells was a protein with a molecular weight of approximately 660,000 to 1 million.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mesopancreatic excision for pancreatic ductal adenocarcinoma improves local disease control and survival

BackgroundSurvival in ductal adenocarcinoma of the pancreatic head (hPDAC) is poor. After implementation of the circumferential resection margin (CRM) into standard histopathological evaluation, the margin negative resection rate has drastically dropped. However, the impact of surgical radicality on survival and the influence of malignant infiltration of the mesopancreatic fat remains unclear. At our institution, a standardized dissection of the mesopancreatic lamina and peri-pancreatic vessels are obligatory components of radical pancreatoduodenectomy. The aim of our study was to histopathologically analyze mesopancreatic tumor infiltration and the influence of CRM-evaluated resection margin on relapse-free and overall survival.MethodClinicopathological and survival parameters of 264 consecutive patients who underwent surgery for hPDAC were evaluated.ResultsThe rate of R0 resection R0(CRM-) was 48.5%, after the implementation of CRM. Mesopancreatic fat infiltration was evident in 78.4% of all consecutively treated patients. Patients with mesopancreatic fat infiltration were prone to lymphatic metastases (N1 and N2) and had a higher rate of positive resection margin (R1/R0(CRM+)). In multivariate analysis, only R0 resection was shown to be an independent prognostic parameter. Local recurrence was diagnosed in only 21.1% and was significantly lower in patients with R0(CRM-) resected hPDACs (10.9%, p < 0.001).ConclusionMesopancreatic excision is justified, since mesopancreatic fat invasion was evident in the majority of our patients. It is associated with a significantly improved local tumor control as well as longer relapse-free and overall survival.