Imaging of Pharmacotherapy Induced Apoptosis

描述(申请人提供)：开发一种成像方法，能够在促凋亡/抗增殖药物治疗过程的早期测量细胞凋亡的增加，将加速对实验性临床前治疗的评估，并允许在临床上对已有的治疗进行个性化。这种成像方法的分子基础在于，当细胞沿着凋亡或死亡的途径进行时，磷脂酰丝氨酸(PS)，一种通常面向细胞质的脂质，翻转并面对细胞外环境。PS是成像药物治疗的一个有吸引力的靶点，因为(I)不同的药物治疗具有共同的诱导细胞凋亡的倾向，(Ii)PS是早期和普遍的细胞凋亡标志，(Iii)PS可以使用Annexin V进行成像，Annexin V是一种选择性地与PS结合的蛋白质，已被用作放射性标记的临床诊断试剂。使用荧光膜联蛋白V，我们已经获得了重要的原理数据证据，即荧光膜联蛋白V(38 KDa)的积累反映了多种疾病(癌症、关节炎)的动物模型对抗增殖药物治疗的早期反应。我们还表明，磁光Annexin V(50 Nm)可以用来在活体内成像MRI诱导的缺血诱导的细胞凋亡。虽然TC-Annexin V已被用于化疗反应的显影，但临床结果可以说是有限的和混合的。这一建议的前提是，如果对Annexin V如何与肿瘤和各种化疗药物在体外应激的血管内皮细胞结合有极大的了解，基于Annexin V的探针可以成功地用于成像化疗诱导的细胞凋亡。此外，必须了解有关Annexin V探针在体内行为的关键变量，包括阐明这些探针的细胞靶点，以及确定化疗引起的肿瘤血量变化是否会使分子标志物PS的定量变得复杂。这一建议将提供有关膜联蛋白V探针与化疗应激细胞相互作用的基本信息，并使细胞凋亡成像能够实现其尚未被认识的巨大潜力。这将为根据正在接受治疗的肿瘤上上调的分子标志物的表达来选择药物治疗方案提供基础，指出哪些方案对特定的个体有效，并避免许多副作用易发生的方案，这些方案没有任何益处。

DESCRIPTION (provided by applicant): The development of an imaging method capable of measuring the increase in apoptosis early in the course of pro-apoptotic/anti-proliferative pharmacotherapies will accelerate the evaluation of experimental pre- clinical therapies and permit the personalization of established therapies in the clinic. The molecular basis for such an imaging method lies in the fact that as cells proceed along pathways to apoptosis or death, phosphatidylserine (PS), a lipid normally facing the cytoplasm, flips and faces the extracellular milieu. PS is an attractive target for imaging pharmacotherapy because (i) diverse pharmacotherapies have a common propensity to induce apoptosis, (ii) PS is an early and general marker of apoptosis and, (iii) PS can be imaged using annexin V, a protein that binds PS selectively and which has been used as a radiolabeled clinical diagnostic agent. Using fluorescent annexin V's, we have obtained important proof of principle data that the accumulation of fluorescent annexin V (38kDa) reflects the early response to anti-proliferative drug treatment in animal models of diverse diseases (cancer, arthritis). We have also shown that a magneto/optical annexin V (50 nm) can be used to image ischemia induced apoptosis by MRI in vivo. Though Tc-annexin V has been used for imaging chemotherapeutic response, clinical results to date are can be described as limited and mixed. The premise of this proposal is that annexin V based probes can be successfully used to image chemotherapy induced apoptosis, provided a vastly improved understanding of how annexin V binds to tumor and endothelial cells stressed by various chemotherapic agents in vitro is obtained. In addition, key variables regarding annexin V probe behavior in vivo must be understood, including elucidation of the cellular targets of these probes and determination of whether chemotherapy induced changes in tumor blood volume complicate the quantitation of the molecular marker, PS. This proposal will provide essential information regarding the interaction of annexin V probes with cells subjected to chemotherapeutic stress, and allow imaging apoptosis to realize its as yet unrecognized and vast potential. It will provide a basis for the selection pharmotherapeutic regimes based on the expression of a molecular marker upregulated on tumors undergoing treatment, indicating which regimes will be efficacious for specific individuals, and sparing many side-effect prone regimes which provide no benefit.