TUMOR RADIOSENSITIZATION USING A NITRIC-OXIDE-NEUTRAL, TUNABLE OXYGEN-BINDING PRO

描述(申请人提供)：实体肿瘤中常见的低氧条件(缺氧)被认为是通过放射治疗(放射治疗，RT)进行癌症临床治疗的主要障碍。此外，肿瘤明显缺氧的癌症患者的生存预后往往很差。鉴于缺氧的临床相关性，实验性RT研究的一个长期目标是通过减弱或利用这种病理生理状态来有效地使实体肿瘤放射增敏。分子氧(氧)是一种天然而有效的放射增敏剂，因此，通过放射治疗有效治疗低氧肿瘤的一个策略是人为地增加它们的氧合。该项目旨在使用加州大学伯克利分校(UC Berkeley)开发的一种新的氧气输送技术--血红素-一氧化氮/氧结合蛋白--来彻底改变癌症患者的放射治疗。H-NOx技术在氧气输送疗法领域体现了四个主要改进：(1)氧结合的H-NOx对一氧化氮(NO)是中性的，与无细胞血红蛋白的高NO反应性和高血压特性相比是有利的；(2)已经设计了50多个H-NOx候选化合物，每个候选H-NOx具有特定的氧气亲和力；整个载体面板显示出1000万倍的氧气亲和力；(3)H-NOx载体的结构在75oC以上是稳定的，并且在室温下化学稳定数周；(4)H-NOX车辆是模块化的，可以对其进行表面修饰，以改变大小、致瘤性或组织靶向性。简而言之，H-NOX技术提供了一个氧气输送工具工具箱，用于在低氧组织和肿瘤中测试其提高氧气水平、增强放射治疗和化疗的能力。为了确定治疗开发的领先候选对象，精选的H-NOX候选对象将被提纯并应用于显示层低氧的多层细胞培养(MCC)。使用灵敏的定量显微镜，将随着时间的推移评估H-NOX对组织块的渗透。一旦建立了组织穿透的动力学，实验将确定H-NOX载体穿透并促进氧从培养基向低氧细胞层扩散时组织缺氧的变化。领先的H-NOX候选化合物显示出有效的组织渗透和减少缺氧的能力，将被用于动物实验。携带人类肿瘤移植瘤的小鼠表现出明显的低氧和对RT的抵抗力，将使用H-NOX载体进行治疗，并将评估与对照组相比肿瘤的低氧程度。药代动力学和毒理学研究将同时进行，以监测H-NOX给药的全身影响。如果这些实验证明了肿瘤缺氧的减少，未来的实验将评估增强的RT肿瘤杀伤，并将促进候选的Lead用于携带低氧肿瘤的癌症患者的测试。 公共卫生相关性：实体肿瘤中常见的低氧条件(缺氧)被认为是通过放射治疗(RT)进行癌症临床治疗的主要障碍。在每年接受RT治疗的500,000名癌症患者中，超过50%的人患有缺氧性肿瘤，反应很差。该项目旨在使用一种突破性的、可调的、稳定的和模块化的氧气输送技术，来彻底改变癌症患者的放射治疗。

DESCRIPTION (provided by applicant): Low oxygen conditions (hypoxia) commonly found in solid tumors are considered a major obstacle for the clinical management of cancer by radiation therapy (radiotherapy, RT). Moreover, cancer patients with significantly hypoxic tumors tend to have a poor prognosis for survival. Given the clinical relevance of hypoxia, a long-time objective of experimental RT research has been to effectively radiosensitize solid tumors by attenuating or exploiting this pathophysiological state. Molecular oxygen (oxygen) is a natural and potent radiosensitizer; thus, one strategy for effectively treating hypoxic tumors by RT is to artificially increase their oxygenation. This project aims to use a novel oxygen-delivery technology developed at the University of California, Berkeley (UC Berkeley)-heme-nitric oxide/oxygen-binding (H-NOX) proteins-to revolutionize RT for cancer patients. The H-NOX technology embodies 4 major improvements over prior efforts in the field of oxygen delivery therapeutics: (1) oxygen-binding H-NOXs are neutral towards nitric oxide (NO), comparing favorably with the high NO reactivity and hypertensive properties of cell-free hemoglobin; (2) over 50 H-NOX candidates have been engineered, each with a specific oxygen affinity; the entire panel of vehicles demonstrate oxygen affinities across a 10-million fold range; (3) H-NOX vehicles are structurally stable above 75 oC, and chemically stable for weeks at room temperature; (4) H-NOX vehicles are modular, and can be surface-modified to alter size, oncotic properties, or tissue targeting. In short, the H-NOX technology provides a toolbox of oxygen delivery vehicles to test in hypoxic tissues and tumors for their capacity to raise oxygen levels and enhance RT and chemotherapy. To identify leading candidates for therapeutic development, select H-NOX candidates will be purified and applied to multilayered cell cultures (MCCs) exhibiting layers of hypoxia. Using sensitive quantitative microscopy, penetration of H-NOX into the tissue mass will be evaluated over time. Once the kinetics of tissue penetration are established, experiments will determine the alteration in tissue hypoxia as H-NOX vehicles penetrate and facilitate oxygen diffusion from the culture media to the hypoxic cell layers. Leading H-NOX candidates that demonstrate effective tissue penetration and reduction of hypoxia will be taken forward into animal studies. Mice carrying human tumor xenografts that exhibit significant hypoxia and resistance to RT will be treated with H-NOX vehicles and tumors will be evaluated for reduction in hypoxia compared to controls. Pharmacokinetic and toxicology studies will be performed in parallel to monitor the systemic effects of H-NOX administration. Should these experiments demonstrate reduction in tumor hypoxia, future experiments will evaluate enhanced RT tumor killing, and lead candidates will be promoted into development for testing in cancer patients carrying hypoxic tumors. PUBLIC HEALTH RELEVANCE: Low oxygen conditions (hypoxia) commonly found in solid tumors are considered a major obstacle for the clinical management of cancer by radiation therapy (radiotherapy, RT). For the 500,000 cancer patients treated with RT each year, more than 50% present with hypoxic tumors and respond poorly. This project aims to use a breakthrough, oxygen-delivery technology that is tunable, stable, and modular, to revolutionize RT for cancer patients.