Determining the kinetics and mechanism of pancreatic tumor regression following genetic deletion of PI3K p110a

确定 PI3K p110a 基因缺失后胰腺肿瘤消退的动力学和机制

• 批准号: 8838577
• 负责人: Stephanie Rose Chapelliquen
• 金额: $ 3.22万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-11 至 2017-09-10
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8838577
• 关键词: Ablation; Address; Affect; Animal Model; Automobile Driving; Biochemical; Cancer Etiology; Cells; Cessation of life; Characteristics; Clinical; Clinical Research; Clinical Trials; DNA Methylation; Development; Diagnosis; Drug Targeting; Ectopic Expression; Enzymes; Excision; Future; Gene Expression; Gene Expression Profile; Genes; Genetic; Goals; Guanine Nucleotide Exchange Factors; Hematopoietic; Histologic; Histological Techniques; Individual; Kinetics; Knockout Mice; Laboratories; Maintenance; Malignant Neoplasms; Malignant neoplasm of pancreas; Methods; Molecular; Mouse Strains; Mus; Mutation; Neoplasm Metastasis; Oncogenes; Oncogenic; Operative Surgical Procedures; Organ; Outcome; Pancreas; Pancreatic Ductal Adenocarcinoma; Pathway interactions; Patients; Phenotype; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Play; Protein Isoforms; RNA Sequences; Radiation therapy; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Role; Sampling; Signal Pathway; Signal Transduction; Signaling Molecule; Staging; Survival Rate; Symptoms; Techniques; Testing; Tetracyclines; Therapeutic; Time; Tissue Extracts; Tissues; Western Blotting; base; cancer therapy; chemotherapy; effective therapy; inhibitor/antagonist; insight; kinase inhibitor; mouse model; mutant; new therapeutic target; novel; pancreatic neoplasm; pancreatic tumorigenesis; programs; protein expression; public health relevance; small molecule; tumor

 DESCRIPTION (provided by applicant): Despite aggressive therapeutic treatment, pancreatic ductal adenocarcinoma (PDA) remains the fourth leading cause of cancer-related death worldwide, with a dismal five-year survival rate. There is a great urgency to understand the molecular mechanisms of PDA formation and progression and to identify new therapeutic targets. Oncogenic Kras has been demonstrated to be the key initiator of PDA and its continued presence is required for PDA progression. However, pharmacological targeting of Kras has thus far been unsuccessful. Oncogenic Kras has several downstream effectors that can be more easily targeted with small molecule inhibitors, including phosphoinositide 3-kinase (PI3K). Our laboratory has previously demonstrated that the PI3K p110α isoform is absolutely required for oncogenic Kras to induce pancreatic tumors in mice. We have now produced a new mouse model to test whether PI3K p110α is also required for maintenance of pancreatic tumors once they are established. Preliminary studies using this novel animal model showed that turning off p110α expression results in complete regression of pancreatic tumors caused by oncogenic Kras. Based on these results, the driving hypothesis of this proposal is that ablation of p110α induces tumor regression through changes in the Kras oncogenic program required to sustain pancreatic tumors. Two Specific Aims will address this hypothesis. Aim 1 will determine the kinetics of tumor regression and identify the earliest timepoint following p110α deletion when the organ is still replete with pancreatic tumors. These p110α-null pancreatic tumors will be characterized in detail by histological and immunohistochemical techniques to investigate mechanisms contributing to tumor regression. Aim 2 will utilize pancreatic tissue extracts prepared at the timepoint identified in Aim 1 to further investigate underlying mechanisms of tumor regression. Biochemical and molecular analyses to examine the activation status and expression of key signaling pathways will be performed. In addition, RNA sequencing will be performed on these pancreatic samples to examine the whole transcriptome in an unbiased manner. Our novel animal model mimics the clinical situation in which patients that have already been diagnosed are treated with a selective PI3K inhibitor. Multiple drugs targeting all or individual PI3K catalytic isoforms, including p110α, are in clinical trials. Positive results fromour study will strongly suggest that p110α is an important drug target in PDA and warrants further clinical investigation.

 描述（由申请人提供）：尽管进行了积极的治疗，胰腺导管腺癌（PDA）仍然是全球癌症相关死亡的第四大原因，5年生存率很低。目前迫切需要了解PDA形成和发展的分子机制，并确定新的治疗靶点。致癌性Kras已被证明是PDA的关键启动子，其持续存在是PDA进展所必需的。然而，迄今为止，Kras的药理学靶向尚未成功。致癌Kras具有几种下游效应物，可以更容易地用小分子抑制剂靶向，包括磷酸肌醇3-激酶（PI 3 K）。我们的实验室先前已经证明，PI 3 K p110α亚型是致癌Kras诱导小鼠胰腺肿瘤所必需的。我们现在已经建立了一种新的小鼠模型，以测试一旦胰腺肿瘤建立，PI 3 K p110α是否也是维持胰腺肿瘤所必需的。使用这种新型动物模型的初步研究表明，关闭p110α表达导致致癌Kras引起的胰腺肿瘤完全消退。基于这些结果，该提议的驱动假设是p110α消融通过维持胰腺肿瘤所需的Kras致癌程序的变化诱导肿瘤消退。两个具体目标将解决这个假设。目的1将确定肿瘤消退的动力学，并确定p110α缺失后的最早时间点， 器官里仍然充满了胰腺肿瘤这些p110α-null胰腺肿瘤将通过组织学和免疫组化技术详细表征，以研究有助于肿瘤消退的机制。目标2将利用在目标1中确定的时间点制备的胰腺组织提取物进一步研究肿瘤消退的潜在机制。将进行生化和分子分析，以检查关键信号传导通路的激活状态和表达。此外，将对这些胰腺样本进行RNA测序，以无偏倚的方式检查整个转录组。我们的新型动物模型模拟了已经诊断的患者用选择性PI 3 K抑制剂治疗的临床情况。靶向所有或个别PI 3 K催化亚型（包括p110α）的多种药物正在临床试验中。本研究的阳性结果提示p110α是PDA的重要药物靶点，值得进一步临床研究。