Targeting GRP78 for p53 activation as anti-cancer therapy

靶向 GRP78 激活 p53 作为抗癌疗法

• 批准号: 9008031
• 负责人: Hua Lu
• 金额: $ 16.37万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9008031
• 关键词: Address; Affinity Chromatography; Antineoplastic Agents; Apoptosis; Apoptotic; Area; Binding; Biochemical; Biological Assay; Biotin; Bortezomib; Cancer Cell Growth; Cancer Model; Cell Cycle Arrest; Cell Nucleus; Cell Survival; Cell surface; Cells; Clinic; Colon; Combined Modality Therapy; Coupled; DNA Repair; Deacetylase; Defect; Development; Disease; Endoplasmic Reticulum; Flow Cytometry; Fluorescence Microscopy; Future; GRP78 gene; Genome Stability; Goals; Growth; Health; Homeostasis; Human; In Vitro; Investigation; Investments; Label; Lung; Maintenance; Malignant Neoplasms; Malignant neoplasm of lung; Mass Spectrum Analysis; Measures; Mediating; Molecular Chaperones; Mutation; Names; Nelfinavir; Neoplasm Metastasis; Normal Cell; Nuclear Translocation; Pathway interactions; Pharmacologic Substance; Play; Prevention; Process; Production; Protein p53; Proteins; Quality Control; Role; Signal Transduction; Stress; TP53 gene; Testing; Transcriptional Activation; Tumor Angiogenesis; Tumor Suppression; Tumor Suppressor Proteins; Xenograft procedure; anticancer activity; anticancer research; biophysical techniques; cancer cell; cancer therapy; celecoxib; drug discovery; endoplasmic reticulum stress; glucose-regulated proteins; improved; insight; mortality; mouse model; neoplastic cell; novel; p53 Signaling Pathway; protein folding; research and development; response; senescence; small molecule; therapy development; therapy resistant; tool; tumor; tumor growth; tumor progression; uptake

DESCRIPTION (provided by applicant): Despite numerous major scientific breakthroughs and tremendous R&D investments in the pharmaceutical sector over the past 3 decades, cancer still is the leading cause of disease-related mortality and awaits further advances toward improved therapy. Intensive effort has been focusing on the tumor suppressor p53 pathway because nearly all cancers show defects in this pathway, over 50% of which have mutations in the TP53 gene itself. We recently discovered Inauhzin (INZ) as a novel non-genotoxic p53 activator. INZ activates p53 by targeting SIRT1 and consequently suppresses tumor growth. In our ongoing studies to explore other possible targets of this compound, we identified a 78-kDa glucose-regulated protein (GRP78, also called BiP) as one of the top INZ target candidates. GRP78 is traditionally regarded as a major endoplasmic reticulum (ER) chaperone and a master regulator of the unfolded protein response (UPR) facilitating protein folding and assembly, protein quality control and regulating ER stress (ERS) signaling. Recent advances using mouse models and cellular approaches have revealed that GRP78 also functions beyond the ER. This discovery is not only critical for better understanding the unique and essential role of GRP78 in cancer development and prevention, but also offers an opportunity for cancer-specific targeting. Interestingly and surprisingly, we have also found that INZ can trigger the nuclear translocation of GRP78 that co-localized with accumulated p53 in the nucleus of cancer cells. Our finding suggests that INZ may regulate GRP78 through mechanisms distinct from the ERS-UPR pathway. Hence, the objectives of this application are to validate GRP78 as another bona fide target of INZ and to elucidate the mechanism underlying the role of GRP78 in INZ-induced p53 activation and anticancer activities. Our central hypothesis is that GRP78 is the direct tumor-specific target for INZ, leading to ER-independent activation of the p53 signaling pathway in cancer, but not normal, cells, and the combination of clinically used ERS/UPR-associated modulators with the p53 activator INZ may be a successful approach for overcoming chemoresistance and eliminating tumors. We will test this hypothesis by addressing the following Specific Aims: (1) to biochemically and biophysically characterize the specific binding of INZ to GRP78 in vitro and in cells; (2) to determine the role of cell-surface GRP78 in INZ uptake and specific cancer targeting, to determine how GRP78 is imported from ER to the nucleus by INZ to mediate p53 activation, and to evaluate the synergistic effect of INZ with clinically used ERS/UPR-associated modulators. Should our exploratory studies demonstrate GRP78 as a cancer specific target for INZ through an ER-independent p53 activation, this would not only provide proof-of-concept evidence for targeting both of the ER Stress/UPR related and p53 signaling pathways for cancer therapy, but would also offer new insights into the role of GRP78 in cancer development and therapy and have a strong impact on the area of molecule-specific anti- cancer drug discovery, particularly in the field of translational cancer research.

描述（由申请人提供）：尽管在过去的30年里，制药行业取得了许多重大的科学突破和巨大的研发投资，但癌症仍然是导致疾病相关死亡的主要原因，并且需要进一步改进治疗方法。由于几乎所有的癌症在这一途径上都存在缺陷，超过50%的癌症在TP53基因本身存在突变，因此人们一直在集中精力研究肿瘤抑制因子p53通路。我们最近发现Inauhzin （INZ）是一种新的非基因毒性p53激活剂。INZ通过靶向SIRT1激活p53，从而抑制肿瘤生长。在我们正在进行的探索该化合物其他可能靶点的研究中，我们确定了一个78 kda的葡萄糖调节蛋白（GRP78，也称为BiP）作为INZ的首选靶点候选之一。GRP78传统上被认为是内质网（ER）的主要伴侣和未折叠蛋白反应（UPR）的主调控因子，促进蛋白质折叠和组装，蛋白质质量控制和调节内质网应激（ERS）信号传导。利用小鼠模型和细胞方法的最新进展表明，GRP78的功能也超出了内质网。这一发现不仅对更好地理解GRP78在癌症发生和预防中的独特和重要作用至关重要，而且为癌症特异性靶向治疗提供了机会。有趣和令人惊讶的是，我们还发现INZ可以触发GRP78的核易位，GRP78与癌细胞细胞核中积累的p53共定位。我们的发现表明INZ可能通过不同于ERS-UPR途径的机制调节GRP78。因此，本应用的目的是验证GRP78是INZ的另一个真正的靶点，并阐明GRP78在INZ诱导的p53激活和抗癌活性中的作用机制。我们的中心假设是GRP78是INZ的直接肿瘤特异性靶点，导致癌症细胞中不依赖er的p53信号通路的激活，而不是正常细胞，并且临床使用的ERS/ uprr相关调节剂与p53激活剂INZ的结合可能是克服化疗耐药和消除肿瘤的成功方法。我们将通过以下具体目标来验证这一假设：(1)在体外和细胞中对INZ与GRP78的特异性结合进行生物化学和生物物理表征；(2)确定细胞表面GRP78在INZ摄取和特异性癌症靶向中的作用，确定GRP78如何通过INZ从ER导入细胞核介导p53激活，并评估INZ与临床使用的ERS/ uprr相关调节剂的协同作用。如果我们的探索性研究能够证明GRP78通过内质网独立的p53激活而成为INZ的癌症特异性靶点，这不仅将为靶向内质网应激/UPR相关和p53信号通路的癌症治疗提供概念验证证据，而且还将为GRP78在癌症发展和治疗中的作用提供新的见解，并对分子特异性抗癌药物的发现领域产生重大影响。尤其是在转化性癌症研究领域。