A sequential therapeutic strategy of senescence induction and senolytics for elimination of surviving residual breast tumor cells

摘要/摘要 化疗和放疗可诱导乳腺肿瘤进入长时间的生长停滞状态 衰老的特点。类似衰老的状态也是存活的残留肿瘤细胞的特征 化疗和/或放射治疗后消除了大部分肿瘤细胞。存活的肿瘤细胞 治疗诱导的衰老在其延长后具有恢复增殖能力的能力 增长停滞。肿瘤细胞从这种生长停滞状态恢复和重新出现可能有助于 在患者显然已治愈原发病几个月或几年后，疾病复发。 最近确定了几种具有感光特性的试剂[例如ABT-263(Navitoclax)] 它可以选择性地杀死衰老的细胞。鉴于这种疾病的复发和随之而来的癌症死亡率 常与原发病部位或原发部位的增殖性肿瘤细胞重新出现有关 转移部位，这个项目的一个主要目标将是检验这一假说，即增感物质可以消除 治疗诱导衰老的乳腺肿瘤细胞预防或至少显著抑制癌症复发。 目标1将验证这样的假设，即感觉剂ABT-263可以有效地消除细胞 在化疗或放射治疗后连续(并可能重复)使用时，会导致衰老 最初的治疗。将评估衰老分选的乳腺肿瘤细胞对衰老药物的敏感性，在此之前 在衰老和恢复过程中，以及在肿瘤大部分后存活的残存人口中 人口已经被治疗剂消灭了。顺序治疗计划的有效性将 也可以使用异种移植和PDX肿瘤模型在体内进行评估。 目标2将询问感觉剂ABT-263在衰老过程中促进细胞死亡的机制 乳腺肿瘤细胞，重点是促凋亡和抗凋亡的bcl2家族蛋白的作用。 目标3将检测单独和治疗后对治疗诱导的衰老细胞的免疫反应。 使用抗衰老药物。肿瘤浸润性免疫细胞的表型评价及选择性免疫研究 小鼠模型中的细胞耗尽将定义抗肿瘤免疫反应的性质(适应性和先天的)。 体外研究将进一步确定在没有或存在的情况下，NK和T细胞介导的衰老细胞的裂解 ABT-263。感觉剂诱导免疫原性细胞死亡的能力将是一个焦点。对寄主的毒性会 在化疗的同时(即进入衰老之前)暴露于促衰老药物的情况进行比较 在诱导衰老之后。

Abstract/Summary Chemotherapy and radiation can induce breast tumors to enter a prolonged state of growth arrest with characteristics of senescence. A senescent-like state is also characteristic of residual tumor cells that survive after chemotherapy and/or radiation have eliminated the bulk of a tumor cell population. Tumor cells surviving therapy-induced senescence have the capacity to recover proliferative capacity subsequent to their prolonged growth arrest. Recovery and re-emergence of tumor cells from this growth-arrested state could contribute to disease recurrence months or years after the patient has apparently been cured of the primary disease. Several agents have recently been identified as having senolytic properties [e.g. ABT-263 (navitoclax)] which can selectively kill senescent cells. Given that disease recurrence and consequent cancer mortality is frequently associated with the re-emergence of proliferative tumor cells either at the primary disease site or metastatic sites, a primary goal of this project will be to test the hypothesis that senolytic agents can eliminate therapy induced senescent breast tumor cells to prevent, or at least significantly suppress, cancer recurrence. Aim 1 will examine the hypothesis that the senolytic agent, ABT-263, can efficiently eliminate cells induced into senescence by chemotherapy or radiation when used sequentially (and potentially, repeatedly) after the initial therapy. Sensitivity to senolytics will be assessed in senescence-sorted breast tumor cells, prior to senescence and during the course of recovery, and in residual populations surviving after the bulk of the tumor population has been eliminated by therapeutic agents. The effectiveness of a sequential treatment schedule will also be assessed in vivo using xenograft and PDX tumor models. Aim 2 will interrogate the mechanisms whereby the senolytic ABT-263 promotes cell death in senescent breast tumor cells, with a focus on the contributions of pro- and anti-apoptotic BCL-2 family proteins. Aim 3 will examine the immune response to therapy-induced senescent cells alone and after treatment with senolytics. A phenotypic assessment of tumor infiltrating immune cells and studies with selective immune cell depletion in mouse models will define the nature (adaptive and innate) of the antitumor immune response. Ex vivo studies will further determine NK- and T cell-mediated lysis of senescent cells in the absence or presence of ABT-263. The ability of senolytics to induce immunogenic cell death will be a focus. Toxicity to the host will be compared for exposure to senolytics concomitant with chemotherapy (i.e. prior to entry into senescence) and subsequent to induction of senescence.