Targeting Cell Surface GRP78 as a Novel Therapy for Pancreatic Cancer

靶向细胞表面 GRP78 作为胰腺癌的新疗法

• 批准号: 8700022
• 负责人: AMY S LEE
• 金额: $ 21.46万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8700022
• 关键词: Address; Affect; Animals; Apoptosis; Biological Models; Biology; Blood Vessels; Cancer Model; Cancer cell line; Cell Death; Cell surface; Cells; Cessation of life; Clinic; Combined Modality Therapy; Complex; Coupled; Data; Desmoplastic; Diagnostic; Endocytosis; Endocytosis Inhibition; GRP78 gene; Genes; Growth; Human; Hypoxia; Image; Immunoglobulin G; Intercellular Fluid; Laboratories; Lead; Lesion; Malignant - descriptor; Malignant Neoplasms; Malignant neoplasm of pancreas; Measures; Metabolism; Modeling; Molecular Chaperones; Monoclonal Antibodies; Mus; Mutation; Normal Cell; Nutrient; Oncogenic; Organ; PI3K/AKT; Pancreatic Ductal Adenocarcinoma; Pathway interactions; Phosphotransferases; Proteins; Proto-Oncogene Proteins c-akt; Regulation; Resistance; Signal Transduction; Stress; Surface; Survival Rate; TNFRSF10A gene; TP53 gene; Testing; Therapeutic; Therapeutic Agents; Translating; Transplantation; Treatment Efficacy; Tumor Suppression; Up-Regulation; Xenograft procedure; arm; base; biological adaptation to stress; cancer cell; cancer therapy; caspase-8; combat; deprivation; efficacy testing; endoplasmic reticulum stress; gemcitabine; glucose-regulated proteins; neoplastic cell; novel; novel strategies; novel therapeutics; pancreatic cancer cells; pancreatic neoplasm; pressure; public health relevance; response; sensor; tumor; tumor growth; tumor progression; tumor xenograft; uptake

DESCRIPTION (provided by applicant): We propose a novel therapeutic strategy to combat pancreatic cancer by targeting the cell surface glucose regulated protein GRP78 (sGRP78), a stress-inducible master chaperone which is actively promoted to the cell surface upon endoplasmic reticulum (ER) stress in cancer cells, while sparing normal organs. Pancreatic ductal adenocarcinoma (PDAC) is one of deadliest of all cancers with a 5 yr survival rate of <5%, thus there is an urgent need for developing an efficacious therapy for PDAC. This proposal is based on emerging evidence from our laboratory and others that in pancreatic cancer GRP78 is prominently expressed in both human and murine pre-invasive and PDAC lesions and sGRP78 co-localizes with activated AKT at the cell surface of PDAC. We have recently discovered a highly specific and potent monoclonal antibody, MAb159, that targets sGRP78 leading to endocytosis, inhibition of the PI3K/AKT pathway, and tumor cell death by inducing apoptosis. Our hypothesis is that pancreatic cancer characterized by a dense stroma is subjected to an adverse microenvironment resulting in hypoxia and nutrient deprivation. This coupled with intrinsic high proliferation and altered metabolism, creates ER stress in the cancer cells leading to GRP78 upregulation and active promotion of GRP78 surface localization as a major pro-survival response. Targeting sGRP78 with MAb159 induces endocytosis and degradation of sGRP78 complex at the cell surface, thereby offering a novel approach to blunt AKT and potentially other oncogenic pathways to suppress tumor growth and synergize with existing therapy in pancreatic cancer. Additionally, MAb159 treatment induces caspase-8 activation, indicative of activation of extrinsic cell death. Aim 1 will determine the mechanisms o action of MAb159 in human PDAC, addressing the requirement of endocytosis, AKT activation, the interactions between sGRP78 and the death-inducing signaling complex and synergy with gemcitabine. Based on our exciting preliminary data that MAb159 not only inhibits but can regress xenograft growth of human PDAC, Aim 2 will test the efficacy of MAb159, alone or in combination therapy, in the Pdx-1Cre; KrasG12D; p53f/+ (PKC) endogenous mouse pancreatic cancer model which recapitulates many of the features of human pancreatic cancer and offers a most vigorous test for agent efficacy. In parallel, the efficacy of MAb159 will be tested in orthotopic transplantation models of human PDAC with complex genetic alterations. In summary, this proposal tests two new concepts: 1) sGRP78 promotes tumor proliferation and survival in part through regulation of the PI3K/AKT pathway and the death-inducing signaling complex in PDAC, and 2) a novel therapeutic agent (MAb159 targeting sGRP78) may reverse tumor growth and resistance while sparing normal cells. The results of this study can be readily applied to other highly malignant and resistant tumors expressing sGRP78 and translatable to the clinic.

描述（由申请人提供）：我们提出了一种通过靶向细胞表面葡萄糖调节蛋白GRP 78（sGRP 78）来对抗胰腺癌的新的治疗策略，该蛋白是一种应激诱导型主伴侣蛋白，在癌细胞中内质网（ER）应激时被主动促进至细胞表面，同时保留正常器官。胰腺导管腺癌（Pancreatic ductal adenocarcinoma，PDAC）是最致命的恶性肿瘤之一，其5年生存率<5%，因此迫切需要开发有效的治疗方法。该提议基于来自我们实验室和其他实验室的新证据，即在胰腺癌中，GRP 78在人和鼠的浸润前和PDAC病变中显著表达，并且sGRP 78与活化的AKT共定位在PDAC的细胞表面。我们最近发现了一种高度特异性和有效的单克隆抗体MAb 159，其靶向sGRP 78，导致内吞作用，抑制PI 3 K/AKT通路，并通过诱导凋亡导致肿瘤细胞死亡。我们的假设是，胰腺癌的特点是致密的基质受到不利的微环境，导致缺氧和营养剥夺。这与内在的高增殖和改变的代谢相结合，在癌细胞中产生ER应激，导致GRP 78上调和GRP 78表面定位的主动促进作为主要的促存活应答。用MAb 159靶向sGRP 78诱导细胞表面sGRP 78复合物的内吞作用和降解，从而提供了一种新的方法来钝化AKT和潜在的其他致癌途径，以抑制肿瘤生长并与胰腺癌中的现有疗法协同作用。此外，MAb 159处理诱导caspase-8激活，表明外源性细胞死亡的激活。目的1将确定MAb 159在人PDAC中的作用机制，解决内吞作用、AKT活化、sGRP 78与死亡诱导信号复合物之间的相互作用以及与吉西他滨的协同作用的需要。基于我们令人兴奋的初步数据，即MAb 159不仅抑制人PDAC的异种移植物生长，而且可以使人PDAC的异种移植物生长消退，Aim 2将在Pdx-1Cre; KrasG 12 D; p53 f/+（PKC）内源性小鼠胰腺癌模型中测试MAb 159单独或联合治疗的功效，该模型重现了人胰腺癌的许多特征，并提供了对药剂功效的最有力的测试。同时，将在具有复杂遗传改变的人PDAC的原位移植模型中测试MAb 159的功效。总之，该提案测试了两个新概念：1）sGRP 78部分地通过调节PI 3 K/AKT通路和PDAC中的死亡诱导信号传导复合物来促进肿瘤增殖和存活，以及2）新型治疗剂（靶向sGRP 78的MAb 159）可以逆转肿瘤生长和抗性，同时保留正常细胞。本研究的结果可以很容易地应用于表达sGRP 78的其他高度恶性和耐药的肿瘤，并可转化为临床。