EGFRvIII in Pancreatic Cancer

描述（由申请人提供）：胰腺癌是美国癌症相关死亡的第四大原因。迫切需要确定新的生物标志物，用于早期诊断和治疗干预的目标。PC细胞中EGFR的过表达在肿瘤细胞不受控制的增殖中起着至关重要的作用。野生型EGFR （EGFRwt）基因的扩增或过表达通常与重排或交替剪接相关，导致EGFR mRNA和蛋白的表达结构改变。EGFRvIII是最常见的自然发生的EGFR突变形式，在许多癌症类型中表达，包括胶质母细胞瘤、乳腺癌、卵巢癌、头颈癌、肺癌和前列腺癌。虽然EGFR及其配体的扩增在胰腺癌中有很好的文献记载，但没有研究EGFRvIII在胰腺癌中的发病率或参与程度。我们的初步结果表明EGFRvIII在胰腺癌组织中高度表达。根据初步研究结果，我们假设“自然发生的表皮生长因子受体变异III （EGFRvIII）参与了胰腺腺癌的发病机制”。为了验证这一假设，提出了以下具体目的：具体目的：我将通过逆转录酶-聚合酶链式反应（RT-PCR）和免疫组织化学分析研究EGFR和EGFR变异在人胰腺肿瘤中的表达。PCR扩增可证实mRNA的表达。使用EGFRvIII特异性单克隆抗体的免疫组织化学分析将表明EGFRvIII蛋白的存在和细胞定位。这一目的将提供关于EGFRvIII在人类胰腺肿瘤中的表达发生率的信息。SPECIFIC AIM II将在高致瘤性（HPAF）和低致瘤性（MiaPaCa）人胰腺癌细胞系和永生化人胰腺导管细胞（HTERT/HPNE）中表达EGFRvIII，以确定其对恶性表型的贡献。这一目标将支持我们的预测，即EGFRvIII在培养的永生胰腺细胞中的表达足以导致表型转化；细胞在软琼脂中可形成病灶，在裸鼠体内可形成肿瘤。综上所述，这些研究将提供一种新的EGFRvIII自然变异在致死性胰腺癌中的发病率和功能。该项目的长期目标是将新开发的抗egfrviii抗体用于胰腺癌的靶向治疗。公共卫生相关性：突变型表皮生长因子受体EGFRvIII由于其肿瘤限制性表达和独特抗原表位的存在而成为靶向治疗的一个有吸引力的靶标。在本次拨款申请中，我们拟研究EGFRvIII在胰腺肿瘤（不同级别的恶性肿瘤）中的表达，其在永生胰腺细胞中的致癌功能，以及其对胰腺癌细胞致瘤性的影响。

DESCRIPTION (provided by applicant): Pancreatic cancer is the fourth leading cause of cancer related death in the United States. There is an urgent need to identify novel biomarkers for early diagnosis and targets for therapeutic interventions. Overexpression of EGFR in PC cells plays a crucial role in the uncontrolled proliferation of neoplastic cells. Amplification or overexpression of the wild-type EGFR (EGFRwt) gene is frequently associated with rearrangements or alternate splicing resulting in the expression of structurally altered EGFR mRNA and protein. EGFRvIII is the most is the most common naturally occurring mutant form of EGFR and is expressed in many cancer types including glioblastoma, breast, ovarian, head and neck, lung and prostate cancer. Although amplification of EGFR and its ligands is well documented in pancreatic cancer, no efforts have been made to study the incidence or involvement of EGFRvIII in pancreatic cancer. Our preliminary results suggest that EGFRvIII is highly expressed in pancreatic cancer tissues. Based on the preliminary findings we hypothesize that "naturally occurring epidermal growth factor receptor variant III (EGFRvIII) contributes to the pathogenesis of pancreatic adenocarcinomas". To test the hypothesis following specific aims are proposed: SPECIFIC AIM I will investigate the expression of EGFR and EGFR variants in human pancreatic tumors by reverse transcriptase- polymerase chain reaction (RT-PCR) and immunohistochemical analysis. PCR- amplification will demonstrate the expression of mRNA. Immunohistochemical analysis using a EGFRvIII specific monoclonal antibody will indicate the presence and cellular localization of the EGFRvIII protein. This aim will provide the information on the incidence of expression of EGFRvIII in human pancreatic tumors. SPECIFIC AIM II will express EGFRvIII in highly tumorigenic (HPAF) and poorly tumorigenic (MiaPaCa) human pancreatic cancer cell lines and immortalized human pancreatic ductal cells (HTERT/HPNE) to establish its contribution to the malignant phenotype. This aim will support our prediction that expression of EGFRvIII in cultured immortal pancreatic cells is sufficient to lead to a transformed phenotype; that the cells will gain the ability to form foci in soft agar and to form tumors in nude mice. Taken together, these studies will provide the incidence and function of a novel naturally occurring variant of EGFRvIII in the lethal pancreatic cancer. The long-term goal of this project is to use the newly developed anti-EGFRvIII antibodies for targeted therapy of pancreatic cancer. PUBLIC HEALTH RELEVANCE: Mutant epidermal growth factor receptor, EGFRvIII is an attractive target for targeted therapy due to its tumor-restricted expression and presence of unique antigenic epitopes. In this grant application, we propose to investigate EGFRvIII's expression in pancreatic tumors (various grades of malignancy), its oncogenic function in immortal pancreatic cells, and its effect on tumorigenecity of pancreatic cancer cells.