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.

项目摘要/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，而且 目前，结直肠癌可供选择的治疗方法仍然非常有限。在结直肠癌和大多数其他人类癌症中， 肿瘤抑制基因TP53常因突变或缺失而失活。因此，巨大的 人们已经努力恢复用于癌症治疗的P53活性。然而，目前还没有基于p53的治疗方法 由于P53信号的复杂性，成功地将其转化为临床癌症治疗。 因此，不是恢复P53的活性，而是识别由TP53缺失或 突变是对抗人类癌症中P53缺失的一种新策略。在最近的一项研究中 发表在《自然》杂志上，我们证实了TP53的基因组缺失经常伴随着部分缺失 邻近的必需基因和具有半合子TP53缺失的癌细胞非常容易受到 进一步抑制这种邻近的必要基因。我们揭示了POLR2A是一个如此重要的基因 在人类癌症中，该基因经常与TP53部分共缺失。这种TP53/POLR2A基因的半合子缺失 在结直肠癌、乳腺癌和胰腺癌中分别为53%、60%和41%。 α-Amanitin(Ama)是一种由8个氨基酸组成的环肽，它特异性地抑制POLR2a的活性 在蘑菇鹅膏菌中。我们证明了低剂量的AMA与抗上皮细胞抗体结合 靶向CRC的细胞黏附分子(EpCAM)抗体可显著增强肿瘤的消退 POLR2A半合子缺失且无明显全身毒性的人结直肠癌小鼠模型。 然而，一小部分结直肠癌细胞被发现以剂量依赖的方式对Ama产生耐药。 这些耐药细胞通常被称为癌症干细胞(CSCs)或肿瘤起始细胞(TICs)。一个 许多癌症(例如，结直肠癌以及乳腺癌和胰腺癌)中CSCs的共同特征是 它们过度表达CD44变异体。我们的初步数据显示，耐阿莫西林的CRC细胞确实是 富含CD44，但不含EPCAM。此外，我们的研究表明，人类的乳腺和前列腺干细胞可以 在体外和体内使用针对该变体的抗癌剂载药纳米粒有效地摧毁 CD44(但不是正常干细胞上的正常或非变异的CD44)，没有明显的全身毒性。 这里，我们假设靶向递送AMA和/或临床上使用的抗癌药物给变异体 带有纳米颗粒的CD44+癌细胞可以克服其耐药性。我们将用两个例子来检验这一假设 具体目的：1、确定抗癌基因POLR2A靶向治疗的耐药机制 Tp53和Tp2基因半合子缺失的人肾细胞癌患者的临床研究 使用的抗癌药物与变种的CD44靶向纳米颗粒一起传递可以克服这种药物 人卵巢癌的耐药性。预计这一项目可能会产生一种针对TP53的新方法 并可能对结直肠癌和其他携带TP53缺陷的癌症的治疗产生重大影响。