Nanotechnology enabled targeting of p53 deficiency in human cancer

纳米技术能够靶向人类癌症中的 p53 缺陷

• 批准号: 9307738
• 负责人: Xiaoming He
• 金额: $ 35.91万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-08 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9307738
• 关键词: Alginates; Alleles; Alpha Cell; Amanita; Amanitins; Amino Acids; Antibodies; Antineoplastic Agents; Biodistribution; CD44 gene; Cancer Patient; Catalytic Domain; Cell Adhesion Molecules; Cells; Clinic; Clinical; Colorectal; Colorectal Cancer; Complex; Cyclic Peptides; Data; Dose; Drug resistance; Encapsulated; Ensure; Epithelial Cells; Essential Genes; Fluorouracil; Gene Dosage; Genes; Genomics; Human; Hydrogels; Hydrophobicity; In Vitro; Malignant Neoplasms; Malignant neoplasm of ovary; Malignant neoplasm of pancreas; Malignant neoplasm of prostate; Mediating; Medicine; Microcapsules drug delivery system; Morbidity - disease rate; Mutation; Nanotechnology; Nature; Normal Cell; Operative Surgical Procedures; POLR2A gene; Permeability; Protein p53; Public Health; Publishing; RNA Polymerase II; Regimen; Research; Resistance; Signal Transduction; Stem cells; TP53 gene; Technology; Testing; Translating; Tumor Initiators; Tumor Suppressor Proteins; Tumorigenicity; Variant; Water; base; cancer cell; cancer therapy; enzyme pathway; experience; fight against; hydrophilicity; improved; in vivo; malignant breast neoplasm; miniaturize; mortality; mouse model; mutant; nanoparticle; novel; novel strategies; overexpression; oxaliplatin; resistance mechanism; stem; stem-like cell; systemic toxicity; targeted delivery; targeted treatment; three dimensional cell culture; tumor; tumorigenic

Project Summary/Abstract There has been little change in mortality rate of human colorectal cancer (CRC) in the past decades and the treatment options available for CRC are still very limited today. In CRC and most other human cancers, the tumor suppressor TP53 gene is frequently inactivated by mutation or deletion. Consequently, tremendous effort has been made to restore the p53 activity for cancer therapy. However, no p53-based therapy has been successfully translated into clinical cancer treatment due to the complexity of p53 signaling. Therefore, instead of restoring the p53 activity, identifying vulnerabilities conferred by TP53 deletion or mutation is a novel strategy for fighting against the p53 deficiency in human cancer. In a recent study published in Nature, we confirmed that genomic deletion of TP53 is frequently accompanied by the partial loss of neighboring essential genes and cancer cells with hemizygous TP53 deletion are remarkably vulnerable to further suppression of such neighboring essential genes. We revealed that POLR2A is such an essential gene that is often partially co-deleted with TP53 in human cancers. Such hemizygous loss of TP53/POLR2A occurs in 53, 60, and 41% of colorectal, breast, and pancreatic cancers, respectively. The POLR2A activity is specifically inhibited by α-Amanitin (Ama), a cyclic peptide of 8 amino acids found in the mushroom Amanita phalloides. We demonstrate that low doses of Ama conjugated with anti-epithelial cell adhesion molecule (EpCAM) antibody for targeting CRC can result in much enhanced tumor regression in murine models of human CRC with hemizygous deletion of POLR2A without evident systemic toxicity. However, a small fraction of CRC cells are found to be resistant to Ama in a dose-dependent manner. These drug-resistant cells are often called cancer stem-like cells (CSCs) or tumor initiating cells (TICs). A common feature of the CSCs in many cancers (e.g., CRC together with breast and pancreatic cancers) is that they overexpress the variant CD44. Our preliminary data show that the Ama-resistant CRC cells are indeed enriched with CD44, but not EpCAM. Moreover, our studies show that human breast and prostate CSCs can be effectively destroyed in vitro and in vivo using anticancer agent-laden nanoparticles that target the variant CD44 (but not the normal or non-variant CD44 on normal stem cells) with no evident systemic toxicity. Here, we hypothesize that targeted delivery of Ama and/or clinically used anticancer drugs to the variant CD44+ cancer cells with nanoparticles can overcome their drug resistance. We will test this hypothesis with two specific aims: 1, to determine the mechanisms of resistance to the Ama-based POLR2A-targted therapy of human CRCs with hemizygous loss of TP53 and 2, to determine if the combined therapy of Ama and clinically used anticancer drugs co-delivered with the variant CD44-targeting nanoparticles can overcome the drug resistance of human CRCs. It is expected that this project may result in a novel approach to targeting TP53 and could have a major impact on the treatment of colorectal and other cancers harboring TP53 deficiency.

项目总结/摘要 在过去的几十年里，人类结直肠癌（CRC）的死亡率几乎没有变化， 目前可用于CRC的治疗选择仍然非常有限。在CRC和大多数其他人类癌症中， 肿瘤抑制基因TP 53常因突变或缺失而失活。因此，巨大 已经努力恢复p53活性用于癌症治疗。然而，目前还没有基于p53的治疗方法。 由于p53信号传导的复杂性，成功地转化为临床癌症治疗。 因此，不是恢复p53活性，而是鉴定TP 53缺失或缺失所赋予的脆弱性。 突变是对抗人类癌症中p53缺陷的新策略。在最近的一项研究中 发表在《自然》杂志上，我们证实TP 53的基因组缺失经常伴随着部分缺失 与邻近的必需基因和癌细胞与半合子TP 53缺失是非常脆弱的， 进一步抑制这些邻近的必需基因。我们发现POLR 2A是一个重要的基因， 在人类癌症中通常与TP 53部分共缺失。TP 53/POLR 2A的这种半合子丢失发生在 在结肠直肠癌、乳腺癌和胰腺癌中分别为53%、60%和41%。 POLR 2A活性被α-鹅膏毒肽（Ama）特异性抑制，Ama是一种发现的8个氨基酸的环肽 在蘑菇鹅膏菌中。我们证明，低剂量的Ama结合抗上皮细胞 用于靶向CRC的细胞粘附分子（EpCAM）抗体可导致在大肠癌中的肿瘤消退大大增强。 具有POLR 2A的半合子缺失的人CRC的鼠模型，而没有明显的全身毒性。 然而，发现一小部分CRC细胞以剂量依赖性方式对Ama具有抗性。 这些耐药细胞通常被称为癌症干细胞（CSC）或肿瘤起始细胞（TIC）。一 许多癌症中CSC的共同特征（例如，CRC与乳腺癌和胰腺癌一起）是， 它们过表达变体CD 44。我们的初步数据表明，抗Ama的CRC细胞确实是 富含CD 44但不富含EpCAM。此外，我们的研究表明，人类乳腺和前列腺CSCs可以 使用靶向该变体的载有抗癌剂的纳米颗粒在体外和体内被有效地破坏 CD 44（但不是正常干细胞上的正常或非变异CD 44），无明显全身毒性。 在此，我们假设，将Ama和/或临床上使用的抗癌药物靶向递送至变异 具有纳米颗粒的CD 44+癌细胞可以克服其耐药性。我们将用两个例子来验证这个假设。 具体目的：1、确定对基于Ama的POLR 2A靶向治疗的耐药机制， 用TP 53和2的半合子缺失的人CRC，以确定Ama和临床上 使用的与变体CD 44靶向纳米颗粒共递送的抗癌药物可以克服药物 人类CRCs的耐药性。预计该项目可能导致靶向TP 53的新方法 并可能对治疗结肠直肠癌和其他TP 53缺陷的癌症产生重大影响。