Exploiting Cancer Metabolism and Drug Efflux with Bystander-Assisted Immunotherapy

抽象的。癌症耐药的两个特征是代谢紊乱和药物外排。在多种药物中- 耐药癌症，这两个过程解除化疗的有效性，最终导致去... 化疗效果降低，死亡率增加。发展中的几个战略试图实现-- 通过调节特定的代谢途径或扰乱药物外流来控制耐药性的影响。具体来说- 通常，这些策略包括抑制剂、干扰RNA和纳米药物方法。然而，一个基金会- 对这些策略的心理挑战是由于干扰新陈代谢或药物外排而产生的脱靶毒性。 由P-糖蛋白(P-gp)介导，因为这些机制对许多健康过程也是关键的 遍及全身。为了解决这个问题，我们的长期目标是开发一种利用 这两种耐药机制共同产生了治疗性的抗癌免疫应答。 我们的中心假设是，合理设计的前药可以促进癌细胞的代谢和药物外流，从而 通过一种我们称之为旁观者辅助免疫的作用机制引起抗癌免疫反应- 不治疗(诱饵)。在诱饵中，酶导向的前药首先被代谢成免疫治疗代谢物 由于耐多药癌细胞的代谢不规律。接下来，免疫治疗剂通过 P-gp介导的药物外流，进入细胞外间隙。这导致了旁观者免疫细胞的激活 局部邻近，启动抗癌免疫反应。因为诱饵需要串联代谢和 药物外排，我们预计对同时表现出这两种耐药表型的多药耐药表型具有独特的增强的特异性 这些过程。为了开发合理设计的诱饵前药，我们首先鉴定了小分子免疫调节剂。 易受药物外流影响的儿童。在同时进行的研究中，我们还开发了合成酶导向 调节免疫疗法活性的基团，并被表达在 耐多药癌细胞的代谢不规律。结合这两个研究领域，我们生成了 酶导向诱饵前药，赋予多药耐药癌症免疫原性。在体外，这是反- 在免疫细胞和表达这些代谢酶和P-gp的癌细胞株的共同培养中得到强化。在- 在体内，我们使用前列腺癌的小鼠模型系统(TRAMP-C2同种异体移植)来证明诱饵有利于 药物的毒性降低，肿瘤体积减小，无进展生存期增加。 免疫功能正常的小鼠的常规免疫疗法。综上所述，我们预计这项研究将 建立诱饵作为一种治疗策略，通过抗药性来增强而不是解除武装。这是我们的 这一策略可能广泛适用于逃避该行动的多药耐药癌症的长期愿景 通过改变新陈代谢和药物外排的传统疗法。

ABSTRACT. Two hallmarks of drug resistance in cancers are irregular metabolism and drug efflux. In multidrug- resistant cancers, both of these processes disarm the efficacy of chemotherapeutics, ultimately resulting in de- creased chemotherapeutic efficacy and increased mortality. Several strategies in development attempt to miti- gate the effects of drug resistance by modulating specific metabolic pathways or disrupting drug efflux. Specifi- cally, these strategies include inhibitors, interference RNAs, and nanomedicine approaches. However, a funda- mental challenge to these strategies is the off-target toxicity that arises from disrupting metabolism or drug efflux mediated by P-glycoprotein (P-gp), as these mechanisms are also critical to a number of healthy processes throughout the body. To address this, our long-term objective is to develop a therapeutic strategy that exploits both of these mechanisms of drug resistance in tandem to generate a therapeutic anti-cancer immune repsonse. Our central hypothesis is that rationally designed prodrugs can co-opt cancer cell metabolism and drug efflux to cause an anti-cancer immune response via a mechanism of action we have termed Bystander Assisted Immu- noTherapy (BAIT). In BAIT, an enzyme-directed prodrug is first metabolized to an immunotherapeutic metabolite by the irregular metabolism of multidrug-resistant cancer cells. Next, the immunotherapeutic is transported, via P-gp-mediated drug efflux, to the extracellular space. This results in the activation of bystander immune cells in local proximity, which initiate an anti-cancer immune response. Because BAIT requires tandem metabolism and drug efflux, we anticipate a uniquely enhanced specificity for multidrug-resistant phenotypes that exhibit both of these processes. To develop rationally designed BAIT prodrugs, we first identify small-molecule immunothera- peutics that are susceptible to drug efflux. In concurrent studies, we also develop synthetic enzyme-directing groups that modulate the activity of immunotherapeutics and are specifically removed by enzymes expressed in the irregular metabolism of multidrug-resistant cancer cells. Combining these two research areas, we generate enzyme-directed BAIT prodrugs that confer immunogenicity to multidrug-resistant cancers. In-vitro, this is con- firmed in co-cultures of immune cells and cancer cell lines that express these metabolic enzymes and P-gp. In- vivo, we use a murine model system for prostate cancer (TRAMP-C2 allograft) to demonstrate that BAIT pro- drugs result in lowered toxicity, decreased tumor volume, and increased progression-free survival, relative to conventional immunotherapeutics in immunocompetent mice. Taken together, we envision that this research will establish BAIT as a therapeutic strategy that is enhanced, rather than disarmed, by drug resistance. It is our long-term vision that this strategy could be widely applicable to multidrug-resistant cancers that evade the action of conventional therapies through altered metabolisms and drug efflux.