Rusalatide Acetate (TP508) Mitigation of Genotoxic Radiation Damage in Human Lens Epithelial Cells

癌症患者从放射治疗中受益，但可能会对非靶向组织产生副作用，包括 白内障。白内障虽然不会直接危及生命，但在医疗、经济和社会方面都有重大影响。 对个人、家庭和整个社会的影响。辐射引起的晶状体混浊是一种复杂的 事件并被归因于萌发上皮中的DNA双链断裂(DSB)，导致 晶状体纤维细胞分化有缺陷，晶状体蛋白质随后出现异常折叠。鲁沙拉特 乙酸乙酯(TP508)是一种辐射调节肽，已被证明可增加受辐射的动物的存活率 通过激活内皮细胞中的信号转导通路，启动DSB的修复，增加 NO水平与内皮细胞功能障碍的逆转。这项调查将确定，在没有 内皮细胞，TP508会对人晶状体上皮细胞(HLEC)产生类似的影响，并减轻 辐射诱导的导致DSB的病理生理途径。假设是通过直接的 辐射后HLEC、TP508处理中分子通路的激活可减轻或修复DSB。在……里面 与关注单一下游机制的其他调查方法不同，这种调查 将研究TP508在多种病理生理途径中的分子活性 HLEC的健康。研究的目的是建立分子活性和最佳剂量阈值，以及 TP508在减轻单次曝光X射线或质子辐射损伤中的治疗时机 HLEC(CRL-11421[B3]和SRA01/04)分别给予0.5Gy1.0Gy2.0Gy4Gy.目标(1)是确定最多的 TP508对辐射诱导的HLEC活力影响的最佳浓度和给药方案 使用克隆存活试验、四甲基偶氮唑蓝试验和细胞倍增时间来评估不同 TP508浓度对照射前后HLECs敏感性的影响目标(2)是 进一步确定TP508对特定HLEC分子反应的影响，使用最优化的 TP508浓度和给药程序对单次辐射照射的比较 使用或不使用TP508，并分析细胞凋亡、坏死、衰老、有丝分裂 突变和蛋白表达；53BP1焦点染色动态的DSB；和蛋白质印迹分析 包括白内障早期标志物淀粉样β蛋白在内的相关信号通路和蛋白质谱 队形。预计研究将提供以下内容：(I)确定TP508是否对 在辐射前后应用不同剂量的辐照HLEC；(Ii)识别分子 不同剂量TP508对HLEC保护作用的机制及蛋白质谱研究 辐射归因于DSB修复；以及(Iii)确定最有效的剂量和时机(在或 照射后)应用TP508。如果开发成功，未来对TP508的研究可能会扩大 其应用于减轻额外的辐射副作用，包括干眼、视网膜病变和口干症。 。

Cancer patients benefit from radiation therapy but can incur side effects to non-targeted tissues including cataracts. Although not directly life threatening, cataract disease has major medical, economic, and social impacts on individuals, families, and society as a whole. Radiation-induced lens opacification is a complex event and has been attributed to DNA double strand breaks (DSB) in the germinative epithelium, leading to defective differentiation of lens fiber cells and subsequent abnormal folding of lens proteins. Rusalatide acetate (TP508) is a radio-modulating peptide that has been shown to increase survival of irradiated animals via activation of signal transduction pathways in endothelial cells, initiating repair of DSB, increasing NO levels and reversing of endothelial cell dysfunction. This investigation will determine if, in the absence of endothelial cells, TP508 will have a similar effect on human lens epithelial cells (HLEC) and mitigate radiation induced pathophysiological pathways that lead to DSB. The hypothesis is that through the direct activation of molecular pathways in irradiated HLEC, TP508 treatment will mitigate or repair DSB. In contrast to other investigative approaches that focus on a single downstream mechanism, this investigation will examine molecular activity of TP508 across multiple pathophysiological pathways associated with the health of HLEC. Study aims are to establish the molecular activity and optimum dosage thresholds, and timing of treatments of TP508 in mitigating X-ray or proton radiation damage with single fraction exposures of 0.5, 1.0, 2.0, or 4 Gy in HLEC (CRL-11421 [B3] and SRA01/04 lines). Aim (1) is to determine the most optimized concentration and administration schedule for TP508 effects on radiation induced HLEC viability using a clonogenic survival assay, MTT assay, and cell doubling time to assess the effects of various concentrations of TP508 on the sensitivity of HLECs applied before and after irradiation. Aim (2) is to further identify the effects of TP508 on specific HLEC molecular responses, using the most optimized concentration and administration schedule of TP508 comparing the single fraction radiation exposures applied with or without TP508, and analyzed with assays for apoptosis, necrosis, senescence, mitotic catastrophe and protein expression; 53BP1 foci staining for dynamics of DSB; and western blot assays for related signaling pathways and protein profiles including amyloid beta, an early marker of cataract formation. Studies are expected to provide the following: (i) determine if TP508 provides a survival effect on irradiated HLEC at different doses applied before and after radiation; (ii) identify if the molecular mechanisms and protein profiles underlying the protective effect of TP508 in HLEC at different doses of radiation are attributed to DSB repair; and (iii) determine the most effective dosage and timing (before or after radiation) of TP508 application. Successfully developed, future investigations of TP508 could expand its application to mitigate additional radiation side effects including dry eye, retinopathy, and xerostomia. .