Biology and Immunology of Pancreatic Cancer Stem Cells in a Novel Mouse Model

描述（由申请人提供）：最近的证据表明，肿瘤在具有自我更新和分化能力的不同细胞（称为癌症干细胞（CSC））的驱动下分层生长。由于缺乏模拟人类疾病的简单小鼠模型，研究实体瘤中CSC的能力受到阻碍。我们最近发现小鼠胰腺CSC，当引入具有正常免疫系统的组织相容性受体时，产生在组织学外观和疾病进展模式方面模仿人类胰腺导管腺癌（PDA）的胰腺肿瘤。本项目的目的是研究对小鼠胰腺CSC的免疫应答，并鉴定将这些细胞与非CSC肿瘤细胞区分开的分子。我们最近发现，在胰腺癌的LSL-KrasG 12 D/+; LSL-p53 R172 H/+; Pdx-1-Cre小鼠模型中，从肝转移中分离的细胞在体外生长并显示CSC标志物。此外，将少至500个细胞注射到免疫活性的组织相容性小鼠中可以产生在组织学上与人胰腺癌难以区分的分化肿瘤。原发性肿瘤以及转移部位被宿主免疫细胞迅速浸润。我们将1）从原发性和转移性肿瘤细胞产生克隆原性鼠胰腺CSC系，并就其形态学、染色体稳定性和癌症干细胞特性来表征这些系; 2）表征荷瘤小鼠和未接种肿瘤的小鼠中对CSC和非CSC的细胞免疫应答; 3）使用基因谱分析来鉴定在CSC与非CSC肿瘤细胞中上调的基因; 4）评估针对CSC表达的分子的短发夹RNA（shRNA）试剂在体外阻断这些细胞的生长和它们在体内产生肿瘤的能力;和5）评估CXCR 4在CSC生长和转移中的作用，并评估宿主细胞（包括免疫细胞）对CXCR 4表达的影响。该项目的发现应该阐明胰腺癌的生物学，并导致确定这种毁灭性疾病的新治疗靶点。 相关性：该模型非常模拟人胰腺癌，为研究胰腺CSC提供了一种新方法。由于我们的CSC具有与胰腺癌中常见的相同的基因突变（Kras，p53），并表达与人类胰腺CSC相同的分子标记物，因此有关这些细胞生物学的知识应证明可用于设计更有效的人类胰腺癌治疗方法。

DESCRIPTION (provided by applicant): Recent evidence suggests that tumors grow in hierarchies driven by distinct cells with the ability to self renew and differentiate, called cancer stem cells (CSCs). The ability to study CSCs in solid tumors has been hampered by a lack of simple mouse models that mimic human disease. We recently discovered mouse pancreatic CSCs that, when introduced into histocompatible recipients with normal immune systems, generate pancreatic tumors that mimic human pancreatic ductal adenocarcinoma (PDA) in terms of histologic appearance and pattern of disease progression. The objective of this project is to study the immune response to murine pancreatic CSCs and identify molecules that distinguish these cells from non-CSC tumor cells. We recently discovered that in the LSL-KrasG12D/+; LSL-p53 R172H/+; Pdx-1-Cre mouse model of pancreatic cancer, cells isolated from liver metastases grow in vitro and display CSC markers. Moreover, as few as 500 cells injected into immunocompetent, histocompatible mice can generate differentiated tumors that are histologically indistinguishable from human pancreatic adenocarcinoma. Primary tumors as well as sites of metastases are rapidly infiltrated with host immune cells. We will 1) generate clonogenic murine pancreatic CSC lines from primary and metastatic tumor cells and characterize these lines with respect to their morphology, chromosomal stability, and cancer stem cell properties; 2) characterize the cellular immune response to CSCs and non-CSCs in tumor-bearing and tumor-naive mice; 3) use gene profiling to identify genes that are upregulated in CSCs versus non-CSC tumor cells; 4) evaluate the ability of short hairpin RNA (shRNA) agents directed at molecules expressed by CSCs to block the growth of these cells in vitro and their generation of tumors in vivo; and 5) evaluate the role of CXCR4 in CSC growth and metastasis and assess the effects of host cells, including immune cells, on CXCR4 expression. The findings from this project should elucidate the biology of pancreatic cancer and lead to the identification of new therapeutic targets for this devastating disease. RELEVANCE: This model, which closely mimics human pancreatic cancer, provides a novel means to study pancreatic CSCs. Since our CSCs have the same genetic mutations (Kras, p53) commonly found in pancreatic cancer and express the same molecular markers as human pancreatic CSCs, knowledge gained about the biology of these cells should prove useful in the design of more effective therapies for human pancreatic cancer.