Mechanism of Tumorigenesis in Pancreatic Epithelial Cell

胰腺上皮细胞肿瘤发生机制

• 批准号: 6917555
• 负责人: PAUL J CHIAO
• 金额: $ 19.35万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6917555
• 关键词: RNA interference; adenocarcinoma; athymic mouse; cell adhesion; cell line; epithelium; gene induction /repression; metastasis; molecular oncology; neoplasm /cancer genetics; neoplastic transformation; nuclear factor kappa beta; oncoproteins; pancreas neoplasms; phenotype; posttranslational modifications; protein structure function

DESCRIPTION (provided by applicant): Pancreatic adenocarcinoma is the fourth leading cause of adult cancer mortality in the United States. The five-year survival rate continues at 1-3%. At the time of diagnosis, most pancreatic cancer patients present with advanced and metastatic disease. Although a genetic profile for pancreatic caner is emerging, it is still unknown how these genetic alterations elicit the unique phenotypes and clinical course of pancreatic cancer. The underlying mechanisms, by which pancreatic epithelial cells become tumorigenic, invasive and metastatic, remain to be elucidated. The advance in understanding of the molecular basis of pancreatic cancer is hindered in part due to the lack of normal human pancreatic ductal epithelial cells for analyzing the role of genetic alterations in tumorigenesis and metastasis, and experimental animal models that recapitulate the molecular pathogenesis and tumor biology of this disease. Therefore, the long-term objective of the proposed research is study the molecular basis of pancreatic tumorigenesis and metastasis using an E6E7-immortalized human pancreatic ductal epithelial (HPDE/E6E7) cells that carry the signature genetic alterations in this disease, and determine the phenotypes induced by these genetic alterations using an orthotopic mouse model. The recent findings show that: (1) mutated K-ras4B (G12V) transformed HPDE/E6E7 and induced weak tumorigenicity in orthotopic mouse model; (2) the K-ras downstream target genes were identified; (3) the mutant IkappaBalpha (S32, 36A) mediated inhibition of constitutive NF-kappaB activation suppressed liver metastasis of pancreas cancer cells in an orthotopic nude mouse model; (4) overexpression of Smad4 inhibits tumorigenesis of pancreatic cancer cell lines. The hypothesis, activation of K-ras and NF-kappaB, or inactivation of Smad4 induces tumorigenic or metastatic phenotype by altering the expression of their downstream target genes in immortalized human pancreatic ductal epithelial cells, will be tested. The specific aims are: (1) Study the mechanism of K-ras induced oncogenic transformation of HPDE/E6E7 cells (2) Determine the function of constitutively activated NF-kappaB in induction of metastasis. (3) Determine the role of Smad4 in initiating tumorigenic and metastatic phenotypes in HPDE/E6E7 cells. Generation of various cell lines that carry the signature mutation of pancreatic cancer should permit the identification of the genetic alterations required in concert to induce tumorigenic and metastatic phenotype of this disease. Furthermore, mechanisms underlying tumor progression, including genomic instability and alterations in signal cascades associated with these pancreatic cancer signature mutations can be analyzed in a relevant in vivo and in vitro context using molecular and biochemical methods. A better understanding of the mechanisms of genetic alterations in induction of tumorigenic and metastatic phenotypes will provide a basis for developing early detection and effective treatment strategies for pancreatic cancer.

描述（由申请人提供）：胰腺腺癌是美国成人癌症死亡率的第四个主要原因。五年生存率持续为1-3％。在诊断时，大多数胰腺癌患者都患有晚期和转移性疾病。尽管出现了胰腺癌的遗传特征，但这些遗传改变如何引起胰腺癌的独特表型和临床过程，仍然尚不清楚。胰腺上皮细胞变成肿瘤，侵入性和转移性的基本机制仍有待阐明。理解胰腺癌分子基础的进步部分受到了阻碍，部分原因是人类胰腺导管上皮细胞缺乏正常的遗传改变在肿瘤发生和转移中的作用，以及重新培养这种疾病的分子病原体和肿瘤生物学的实验动物模型。因此，提出的研究的长期目标是研究胰腺肿瘤发生和转移的分子基础，使用E6E7剥离的人类胰腺导管上皮细胞（HPDE/E6E7）细胞，这些细胞在这种疾病中带有遗传型的遗传型，这些疾病中的遗传型在这种疾病中带来了遗传的遗传变化。最近的发现表明：（1）突变的K-RAS4B（G12V）转化了HPDE/E6E7，并在原位小鼠模型中诱导了弱肿瘤性； （2）鉴定出K-RAS下游靶基因； （3）突变体Ikappabalpha（S32，36A）介导了对原位裸小鼠模型中胰腺癌细胞的肝脏转移的抑制抑制了胰腺癌细胞的肝转移； （4）SMAD4的过表达抑制胰腺癌细胞系的肿瘤发生。测试将测试假设，K-RAS和NF-kappab或SMAD4的灭活，通过改变永生的人类胰腺导管上皮细胞中其下游靶基因的表达来诱导肿瘤性或转移性表型。具体目的是：（1）研究K-RAS诱导的HPDE/E6E7细胞的致癌转化（2）确定组成型激活的NF-kappab在诱导转移中的功能。 （3）确定SMAD4在HPDE/E6E7细胞中启动致瘤和转移表型中的作用。携带胰腺癌的特征突变的各种细胞系的产生应允许鉴定该疾病的肿瘤性和转移性表型所需的遗传改变。此外，可以使用分子和生化方法在相关的体内和体外环境中分析肿瘤进展的机制，包括基因组不稳定性和与这些胰腺癌特征突变相关的信号级联反应的改变。更好地理解遗传改变肿瘤和转移性表型的遗传改变的机制将为胰腺癌的早期检测和有效的治疗策略提供基础。