Development of a novel targeted therapy using gold nanoparticles for dose enhancement of X-ray irradiation for the treatment of triple-negative breast cancer (Acronym: TaGoNaX)

金纳米粒子在放射治疗中显示出作为放射增敏剂的潜力。第一个成功的实验是在X射线照射后使用金纳米颗粒提高小鼠肿瘤的放射敏感性，这引发了更多的实验和理论研究。这一研究领域的主要挑战之一是靶向结构的有限可用性，这种结构使得金纳米颗粒能够选择性地被肿瘤细胞摄取。在这项提案中，我们将研究膜热休克蛋白70(Hsp70)在肿瘤细胞上的作用，作为增强和选择性摄取金纳米颗粒的靶点，以增强基于X射线的放射治疗的疗效。研究结果可为在临床前和临床放射治疗环境中使用纳米金作为增敏剂的决策提供定量信息。在第一步中，Hsp70特异性抗体cmHsp70.1将连接到不同大小和形状的金纳米颗粒(AuNP-cmHsp70.1)。将cmHsp70.1抗体偶联到AuNPs上，应该能够使金纳米颗粒针对肿瘤特异性靶向致瘤小鼠乳腺细胞(4T1)和来自患者的原代乳腺癌细胞培养，因为Hsp70只在癌细胞表面表达，而不在正常细胞上表达。透射电子显微镜和动态光散射成像将成像细胞内金纳米颗粒的位置和分布。在第二步中，将在慕尼黑工业大学Klinikum rechts der Isar的辐射设施对含有和不含金纳米颗粒的细胞进行X射线照射。在第三步中，将比较确定有或没有AuNPs-cmHsp70.1的照射后的癌细胞的DNA损伤和细胞存活，并将定量地确定金纳米颗粒和X射线诱导的增强的物理和生物效应。最有希望的AuNP-cmHsp70.1结合物将在原位乳腺癌小鼠模型中进行放射增敏效应测试。在进行生物实验研究的同时，利用蒙特卡罗辐射输运模拟方法对金纳米粒子在X射线照射下的剂量增强进行了模拟，给出了癌细胞内的定量细胞剂量。将开发一个数学模型来分析增强的生物终点之间的关系，如DNA链断裂和细胞存活率，以及沉积在细胞水平和肿瘤小鼠模型中的物理辐射剂量。最后，辐射剂量-效应关系可以为更好地理解金纳米粒子作为增敏剂在乳腺癌放射治疗中的作用机制提供基础信息。

Gold nanoparticles show potential as radiosensitizers in radiation therapy. The first successful experiment using gold nanoparticles to increase the radiosensitivity of tumours in mice after irradiation with X-rays stimulated extended experimental and theoretical investigations. One of the major challenges in this research field is the limited availability of target structures that enables a selective uptake of gold nanoparticles into tumour cells. In this proposal, we will investigate the role of membrane heat shock protein 70 (Hsp70) on tumour cells as a target for an enhanced and selective uptake of gold nanoparticles to enhance the efficacy of X-ray based radiation therapy. The research results can provide quantitative information for the decision of using gold nanoparticle as sensitizers in preclinical and clinical radiation therapy settings. In a first step, the Hsp70-specific antibody cmHsp70.1 will be conjugated to gold nanoparticles with different sizes and shapes (AuNP-cmHsp70.1). The coupling of the cmHsp70.1 antibody to AuNPs should enable a tumour-specific targeting of gold nanoparticles into tumorigenic mouse mammary gland cells (4T1) and primary breast cancer cell cultures derived from patients, as Hsp70 is exclusively expressed on the surface of cancer cells, but not on normal cells. Transmission electron microscopy and dynamic light scattering imaging will image the location and distribution of gold nanoparticles inside the cells. In a second step, an X-ray irradiation of the cells with and without gold nanoparticles will be performed at the radiation facilities at the Klinikum rechts der Isar, Technical University of Munich. In a third step, DNA damage and cell survival will be determined comparatively in irradiated cancer cells with and without AuNPs-cmHsp70.1 and the enhanced physical and biological effects induced by gold nanoparticles and X-rays will be determined quantitatively. The most promising AuNP-cmHsp70.1 conjugates will be tested in orthotopic breast cancer mouse models with respect to their radiosensitizing effects. Parallel to the biological experimental investigations, Monte Carlo radiation transport simulations of dose enhancement of gold nanoparticles irradiated by X-rays provide a quantitative cellular dose in the cancer cells. A mathematical model will be developed to analyse the relationship between the enhanced biological endpoints, such as DNA strand breaks and cell survival fractions and physical radiation doses deposited in the cellular level and in tumour mouse-models. Finally, the radiation dose-response relationship can provide basic information for a better understanding of the mechanisms of gold nanoparticles as sensitizers in radiation therapy of breast cancer.