Novel therapeutics for the targeted eradication of DDR-defective tumors

靶向根除 DDR 缺陷肿瘤的新疗法

• 批准号: 10734414
• 负责人: Ranjit Bindra
• 金额: $ 65.42万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-25 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10734414
• 关键词: Address; Alkylating Agents; Alkylation; Apoptosis; Biological Availability; Cells; Central Nervous System Agents; Chemicals; Clinic; Colon Carcinoma; Cyclization; Cytosine; DNA; DNA Alkylation; DNA Damage; DNA Interstrand Crosslinking; DNA Repair; DNA Repair Disorder; DNA Repair Gene; Data; Dealkylation; Development; Drug resistance; Excision; Futile Cycling; Genes; Genetic; Genome; Genomics; Glioblastoma; Glioma; Goals; Grant; Guanosine; Human; Hypermethylation; Ions; Kinetics; Lesion; MGMT gene; Malignant Neoplasms; Malignant neoplasm of lung; Mediating; Methyltransferase; Mismatch Repair; Modeling; Modification; Mutagens; Non-Small-Cell Lung Carcinoma; Oligonucleotides; Oral; Pathway interactions; Patients; Penetration; Pharmaceutical Preparations; Phenotype; Polymerase; Prodrugs; Proliferating; Radiation therapy; Reaction; Research; Resected; Resistance; Structure; Testing; Therapeutic; Therapeutic Index; Thymine; Time; Tissues; Toxic effect; Transferase; Translating; Translations; Work; adduct; bench to bedside; chemotherapy; clinically significant; crosslink; cytotoxicity; design; efficacy evaluation; experience; functional loss; improved; in vivo; ineffective therapies; inhibitor; mouse model; new therapeutic target; novel; novel strategies; promoter; repaired; response; small cell lung carcinoma; standard of care; synergism; systemic toxicity; targeted agent; temozolomide; tissue culture; treatment strategy; trial design; tumor; tumor specificity

PROJECT SUMMARY/ABSTRACT. O6-Methylguanine methyltransferase (MGMT) reverts O6-alkylguanosine residues to guanosine via dealkylation by SN2 displacement. MGMT is ubiquitously expressed in healthy tissue but is silenced (referred to as “MGMT– “) in ~50% of glioblastomas (GBMs), most gliomas, and in up to 40% of colon cancers, 35% of small cell lung cancers, and 25% of non-small cell lung cancers. MGMT– tumors are sensitized to DNA alkylation agents, such as temozolomide (TMZ). This sensitization creates a therapeutic index (TI). TMZ prolongs survival of patients with MGMT– GBM by ~8 mo. The cytotoxicity of TMZ relies on an intact DNA mismatch repair (MMR) pathway. MMR silencing (referred to as “MMR–”) is the primary mechanism of acquired TMZ resistance, and second-line therapies are ineffective. Despite >20 y of research, efforts to overcome MMR silencing-based resistance have not been successful. Herein, we present 2-fluoroethylating agents (FEtAs) as novel, orally bioavailable com- pounds that selectively eradicate MGMT–/MMR– GBM in vivo, without systemic toxicity. Our data indicate FEtAs induce DNA interstrand cross-links (ICLs) only in MGMT– tumors by formation of O6-(2-fluoroethyl)guanosine (O6FEtG), slow cyclization to an N1,O6-ethanoguanine (EG) intermediate, and ring-opening by the adjacent cytosine. The slow rates of EG formation provide time for MGMT to reverse the initial alkylation in healthy (e.g., MGMT+) cells, leading to a high TI. In contrast, chloroethylation agents, such as mitozolomide, generate O6-(2- chloroethyl)guanosine (O6ClEtG), which cyclizes to EG competitively with MGMT reversal. This leads to the formation of ICLs or toxic DNA–MGMT cross-links, via opening of EG by MGMT, in healthy cells. Additionally, the chloroethylsulfide formed on MGMT reversal of O6ClEtG converts to a reactive episulfonium ion, which also cross-links MGMT to DNA, while MGMT reversal of O6FEtG creates a stable fluoroethylsulfide. Together, these differences lend a higher MGMT TI to FEtAs suggesting they are likely to display improved tolerability in humans. Since ICL toxicity is MMR-independent, FEtAs retain activity in TMZ-resistant, MMR– tumors. Here we will study the amount of O6FEtG formed from FEtAs and the rate of its reversal by MGMT. We will characterize the structure and reaction kinetics of the ICLs using oligonucleotides containing a single O6FEtG. We will conduct studies to improve FEtA CNS penetration. We will probe for synergy between FEtAs and DDR inhibitors, other DNA repair deficiencies, and radiotherapy. Completion of this research will lead to the identification of novel chemotherapies with high CNS penetration that operate by a novel, MMR-independent mechanism, thereby addressing acquired TMZ resistance. As FEtAs are structurally-related to TMZ, we expect rapid translation to the clinic. MGMT is silenced in a range of tumor types; this work will set the stage to evaluate FEtAs as treatments for other MGMT– tumors, alone or in combination regimes. Finally, to the best of our knowledge, the relative rates of DNA chemical modification and repair have not previously been exploited to obtain tumor specificity; we believe this “kinetic lethal” strategy may constitute the first iteration of a new approach to targeted chemotherapeutic design.

项目总结/摘要。 O 6-甲基鸟嘌呤甲基转移酶（MGMT）通过脱烷基化将O 6-烷基鸟苷残基还原为鸟苷 SN 2位移MGMT在健康组织中普遍表达，但被沉默（称为“MGMT-1”）。 “）约50%的胶质母细胞瘤（GBM），大多数胶质瘤，以及高达40%的结肠癌，35%的小细胞肺癌， 癌症和25%的非小细胞肺癌。MGMT-肿瘤对DNA烷基化剂敏感，如 替莫唑胺（TMZ）。这种致敏作用产生了治疗指数（TI）。TMZ降低患者生存率 MGMT- GBM约8个月。TMZ的细胞毒性依赖于完整的DNA错配修复（MMR）途径。 MMR沉默（称为“MMR-”）是获得性TMZ抗性的主要机制，并且二线抑制剂是获得性TMZ抗性的主要机制。 治疗无效。尽管进行了超过20年的研究，但克服MMR沉默耐药性的努力仍然存在。 没有成功。在此，我们提出了2-氟乙基化剂（FEtAs）作为新的，口服生物可利用的com... 在体内选择性地根除MGMT-/MMR-GBM，而没有全身毒性。我们的数据显示FEtAs 通过形成O 6-（2-氟乙基）鸟苷仅在MGMT-肿瘤中诱导DNA链间交联（ICL） （O 6 FEtG），缓慢环化为N1，O 6-乙醇鸟嘌呤（EG）中间体，并通过相邻的 胞嘧啶EG形成的缓慢速率为MGMT逆转健康（例如， MGMT+）细胞，导致高TI。相比之下，氯乙基化剂，如米托唑胺，产生O 6-（2- 氯乙基）鸟苷（O 6ClEtG），其与MGMT逆转竞争性地环化为EG。这导致 在健康细胞中，通过MGMT打开EG形成ICL或毒性DNA-MGMT交联。此外，本发明还 在O 6ClEtG的MGMT反转时形成的氯乙基硫转化为反应性表锍离子，其还 交联MGMT到DNA，而MGMT逆转O 6 FEtG创建一个稳定的氟乙硫醚。所有这些 这些差异使FEtA具有更高的MGMT TI，表明它们可能在人体中显示出改善的耐受性。 由于ICL毒性是MMR非依赖性的，因此FEtA在TMZ耐药的MMR肿瘤中保留活性。在这里我们将学习 由FEtA形成的O 6 FEtG的量及其被MGMT逆转的速率。我们将描述这个结构 和使用含有单个O 6 FEtG的寡核苷酸的ICL的反应动力学。我们会进行研究， 改善FEtA CNS渗透。我们将探索FEtAs和DDR抑制剂之间的协同作用， 缺乏和放射治疗。这项研究的完成将导致确定新的化学疗法 具有高CNS渗透性，通过一种新的、MMR非依赖性机制发挥作用，从而解决获得性 TMZ抗性。由于FEtA与TMZ在结构上相关，我们希望快速转化为诊所。MGMT是 在一系列肿瘤类型中沉默;这项工作将为评估FEtAs作为其他MGMT的治疗奠定基础- 肿瘤，单独或组合方案。最后，据我们所知，DNA化学物质的相对速率 修饰和修复以前没有被利用来获得肿瘤特异性;我们相信这种“动力学” “致死”策略可能构成靶向化疗设计新方法的第一次迭代。