Finding Sleeping Beauty: T Cell Biosensors for Dormant Cancer Detection

项目摘要 某些类型的癌症，如雌激素受体阳性乳腺癌，可作为转移性复发， 在休眠期之后的许多年或甚至几十年，患者没有表现出临床症状。 症状晚期复发被认为是由于最初的化疗没有杀死播散的肿瘤细胞（DTC）引起的。 它们在转移部位（如骨髓）处于休眠状态，直到它们重新唤醒。令人惊讶的是，Meta- 对超过60，000例接受内分泌治疗的早期ER阳性乳腺癌患者的分析显示， 复发的相对风险在至少20年的时间内逐渐增加，表明 没有疾病证据的完全缓解患者可能患有潜伏性癌症，并仍面临癌症风险 转移性复发的风险。目前，还没有广泛使用的方法来监测休眠的 国，也不是它的复兴。癌症免疫疗法的到来揭示了令人兴奋的可能性， 工程化T细胞作为活的药物。T细胞设计有肿瘤靶向受体和复杂的遗传 在某些癌症患者中，这些电路已经导致了惊人的治疗反应，这些癌症以前是 无法治愈这一刻是一个机会，不仅可以建立一个T细胞被设计为治疗方法的未来， 还可以作为活体传感器，以超出目前的灵敏度和特异性检测癌症， 可能休眠肿瘤细胞的激活和生长成为微转移需要标志 在关键步骤如血管生成过程中蛋白酶的表达。为了利用蛋白酶失调，该项目 将开发出能感知蛋白水解的工程受体，以检测苏醒。它们含有一种细胞外的 被肽模拟表位阻断的单链抗体，从而它们可以与其同源抗原结合 只有在封闭肽被蛋白水解去除后，才能将T细胞活化限制在特定条件下 其中同源蛋白酶和肿瘤抗原都存在。激活后，T细胞传感器放大了 释放合成生物标志物（血液、尿液和成像）用于检测。基因编码文库（>10^4） 蛋白酶可激活受体将允许在体内筛选1000个候选T细胞传感器， 并消极地选择可以在不同的微环境中报告觉醒的结构， 骨髓和肺具有记忆表型的T细胞传感器的过继转移可能导致终身 T细胞传感器持续监测未来的疾病。这些技术突破将对 了解休眠细胞如何以及何时重新唤醒并指导治疗干预的意义 复活的最早阶段。

PROJECT SUMMARY Some types of cancers, as exemplified by estrogen receptor positive breast cancer, can recur as metastatic disease many years or even decades following a dormancy period where the patient displays no clinical symptoms. Late recurrence is thought to arise from disseminated tumor cells (DTCs) that were not killed by initial treatment and that lie dormant at metastatic sites such as the bone marrow until they reawaken. Strikingly, meta- analysis of over 60,000 early-stage ER-positive breast cancer patients treated with endocrine therapy revealed that the relative risk of recurrence progressively increases over a period of at least 20 years, indicating that patients in complete remission with no evidence of disease could harbor dormant cancer and remain at risk of metastatic relapse for the remainder of their life. Currently, there is no widely used method to monitor the dormant state nor its reawakening. The arrival of cancer immunotherapy has revealed exciting possibilities using engineered T cells as living medicines. T cells designed with tumor-targeting receptors and sophisticated genetic circuits have led to striking treatment responses in patients with certain types of cancers that were previously untreatable. This moment is an opportunity to not only build a future where T cells are engineered as therapies, but also as living sensors that can detect cancer with sensitivities and specificities beyond what is currently possible. The activation and growth of dormant tumor cells into micro-metastases require the hallmark expression of proteases during key steps such as angiogenesis. To exploit protease dysregulation, this project will develop engineered receptors that sense proteolysis to detect reawakening. These contain an extracellular single chain antibody that is blocked by a peptide mimotope such that they can bind to their cognate antigens only after the blocking peptide is removed by proteolysis, restricting T cell activation to the specific condition where the cognate protease and tumor antigen are both present. Following activation, T cell sensors amplify the release of synthetic biomarkers (blood, urine and imaging) for detection. Genetically encoded libraries (>10^4) of protease-activatable receptors will allow in vivo screening of 1000s of candidate T cell sensors to positively and negatively select for constructs that can report on awakening in different microenvironments such as the bone marrow and lungs. The adoptive transfer of T cell sensors with memory phenotype could lead to life-long T cell sensors that continuously monitor for future disease. These technological breakthroughs will have huge implications in understanding how and when dormant cells reawaken and guide therapeutic interventions at the earliest stages of reactivation.