Effects of silencing RNAs for gastrin and CCK on human 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，其5年生存率不到1%，是所有恶性肿瘤中最低的。胰腺癌预后差的原因与早期无法诊断和对标准化疗的耐药有关。我们的研究小组一直在研究胰腺癌的生长调节机制，并为早期诊断和治疗设计策略。我们发现胰腺癌的生长在一定程度上受胃肠肽胃泌素和胆囊收缩素（CCK）通过独特的CCK受体产生的自分泌调节。通过反义技术减少胃泌素的表达和产生，在培养和动物模型中显著损害胰腺癌的生长，并与肿瘤转移的显著减少有关。最近，一种利用短发夹RNA沉默RNA的方法已被证明比反义技术更有效，并具有治疗干预的潜力。我们的团队设计、开发并优化了一种聚乙二醇化阳离子脂质体递送系统，该系统具有以肿瘤靶向方式递送siRNA的能力。本研究假设可以通过减少肽胃泌素和/或CCK的表达来抑制人类胰腺癌的生长。为了验证这一假设，我们提出了以下具体目标：1)通过shRNA（小发夹RNA）技术沉默CCK和胃泌素的表达，消除胰腺癌细胞的胃泌素或CCK的产生并作用于胰腺癌细胞；2)在原位小鼠肿瘤原发生长和转移模型中分析体内表达胰腺癌细胞的胃泌素/CCK shRNA； 3)测试神经酰胺结合脂质体在体外和体内向胰腺癌细胞传递siRNA的效果。这些研究是申请人长期目标的一部分，目的是将已经了解的胰腺癌细胞水平的生长调节应用于患者护理。这些研究是将基础科学研究成果过渡到临床领域的第一步。如果在动物模型中显示有效，我们计划继续治疗胰腺癌患者。

DESCRIPTION (provided by applicant): Pancreatic cancer is the 4th leading cause of cancer-related deaths in the United States and with the five-year survival rate of less than 1%, it remains the lowest of all malignancies. The reasons why the prognosis for pancreatic cancer is poor are related to the inability to diagnose this malignancy in early stages and because of its resistance to standard chemotherapy. Our research group has been studying the mechanisms involving growth regulation of pancreatic cancer with the long-range goals of designing strategies for early diagnosis and treatment. We have found that growth of pancreatic cancer is in part regulated by the autocrine production of the gastrointestinal peptides gastrin and cholecystokinin (CCK) through a unique CCK receptor. Decreased expression and production of gastrin through antisense techniques significantly impairs pancreatic cancer growth in culture and in animal models and is associated with a marked reduction in tumor metastases. Recently a method to silence RNA using short hairpin RNAs has been shown to be more effective than antisense techniques and has potential for therapeutic intervention. Our team has designed, developed and optimized a pegylated cationic liposome delivery system that has the capability of delivering siRNA in a tumor-targeted modality. This grant hypothesizes that growth of human pancreatic cancer can be inhibited by decreasing the expression of the peptides gastrin and / or CCK. In order to test this hypothesis, the following specific aims are proposed: 1) Abolition of gastrin or CCK production by, and action on, pancreatic cancer cells through silencing of CCK and gastrin expression by shRNA (small hairpin RNA) technology; 2) Analyze the gastrin/CCK shRNA expressing pancreatic cancer cells in vivo in an orthotopic mouse model for primary tumor growth and metastasis, and 3) test the effect of ceramide-incorporated liposomes designed to deliver siRNA in vitro and in vivo to pancreatic cancer cells. These studies are part of the applicant's long-term goals to apply what has been learned about growth regulation of pancreatic cancer at the cellular level to patient care. These studies are the first step in bridging the results from basic science studies into the clinical realm. If shown to be effective in the animal model, we plan to proceed to treating subjects with pancreatic cancer.