Toward development of senolytic CAR T cells

总结 衰老是一种应激反应程序，为癌症进展和恢复提供了有力的屏障。 在晚期癌症中使用这种程序可以产生有效的抗肿瘤效果。相反， 衰老细胞在组织中的积累导致与老化和受损组织相关的病理学， 使得从这些组织中消除衰老细胞可以改善小鼠的疾病症状。 因此，引发癌症衰老或消除老年或受损细胞中衰老细胞的策略 具有潜在的临床意义。从表面上看，细胞衰老包括两个组成部分， 过程：一方面，p53和RB肿瘤抑制因子控制一个基因抑制程序，导致稳定的 细胞周期停滞;另一方面，转录激活因子如NF-κ B执行基因激活程序， 导致产生一系列分泌的或细胞表面的蛋白质，统称为衰老 相关分泌表型（SASP）。SASP的分子组成和生物学作用如下： 多种多样，但SASP因子包括生长因子、免疫调节剂和基质金属蛋白酶，因此 这一过程既有助于抗肿瘤作用，也有助于衰老的有害后果 在老化或受损的组织中。我们的团队结合了Lowe实验室在衰老方面的广泛专业知识 Sadelain小组在开发嵌合抗原受体T方面的创新， (CAR T）细胞，其能够靶向细胞表面蛋白用于治疗目的。我们的目标是找出新的 在衰老细胞中选择性表达的细胞表面标志物，用于更好地鉴定和 表征组织中的衰老细胞并作为衰老相关疾病的生物标志物。同时，我们 利用这些分子的选择性特征，目的是产生衰老清除CAR T细胞，然后我们 在临床前衰老模型中进行表征，如果成功，则可用作询问衰老的工具 体内生物学初步数据有力地支持了拟议工作的可行性：我们已经确定 一种主要在衰老细胞上表达并产生CAR T细胞的细胞表面分子 我们进一步提供了初步的数据来证明这些CAR T细胞的行为是真实的， 能够消除培养物和小鼠中的衰老细胞。在我们的申请中，我们继续 验证蛋白质和CAR T细胞作为有用的工具和临床前模型，并致力于开发 增强版本的CAR T，经过进一步验证，可以在临床上开发。我们期望我们 研究，以更好地定义衰老状态，产生新的见解衰老生物学，并产生新的 用于治疗衰老相关病理的治疗方式。

SUMMARY Senescence is a stress response program that provides a potent barrier to cancer progression, and restoration of this program in advanced cancers can produce potent anti-tumor effects. Conversely, the aberrant accumulation of senescent cells in tissues contributes to pathologies associated with aged and damaged tissue, such that elimination of senescent cells from these tissues can ameliorate disease symptoms in mice. Consequently, strategies to trigger senescence in cancer, or eliminate senescent cells in aged or damaged tissues, are of potential clinical significance. Superficially, cellular senescence involves a two component process: on one hand, the p53 and RB tumor suppressors control a gene repression program that leads to stable cell cycle arrest; on the other hand, transcriptional activators such as NF-kB execute a gene activation program, leading to the production of a range of secreted or cell surface proteins collectively known as the senescence associated secretory phenotype (SASP). The molecular composition and biological roles of the SASP are diverse, but SASP factors include growth factors, immune modulators and matrix metalloproteinases, and thus the process can contribute to both the anti-tumor effects but also to the deleterious consequences of senescence in aged or damaged tissues. Our team combines the extensive expertise of the Lowe laboratory in senescence mechanisms and biology with the innovation of the Sadelain group in developing chimeric antigen receptor T (CAR T) cells capable of targeting cell surface proteins for therapeutic purposes. Our goals are to identify novel cell surface markers that are selectively expressed in senescent cells for the purpose of better identifying and characterizing senescent cells in tissues and as biomarkers for senescence related diseases. In parallel, we exploit the selective features of these molecules with the aim of producing senolytic CAR T cells, which we then characterize in preclinical senescence models and, if successful, apply as tools to interrogate senescence biology in vivo. Preliminary data strongly supports the feasibility of the proposed work: we have already identified one cell surface molecule that is predominantly expressed on senescent cells, and produced CAR T cells targeting it. We further provide preliminary data to demonstrate that these CAR T cells behave as bona fide senolytics, capable of eliminating senescent cells in culture and in mice. In our application, we continue to validate the protein and CAR T cells as useful tools and in preclinical models, and work towards the development of enhanced versions of the CAR T that, with further validation, could be developed clinically. We expect our studies to better define the senescent state, produce new insights into senescence biology, and produce a new therapeutic modality for treating senescence associated pathologies.