Harnessing the therapeutic potential of histotripsy focused ultrasound-induced immunogenic cancer cell death

项目概要/摘要 免疫疗法可以非常有效地对抗引起免疫系统识别的癌症。 系统（例如，黑色素瘤），但它对免疫检测基本上不可见的癌症仍然无效 (e.g.,胰腺癌）。癌症免疫疗法的进步将需要干预措施， 对免疫系统更明显。越来越多的证据表明，聚焦超声（FUS） 肿瘤消融术可能是一种干预手段。通过非侵入性破坏癌细胞，热和机械 FUS的模式已经显示出触发针对肿瘤的令人惊讶的有效免疫应答。我们有 发现组织摧毁术，一种机械FUS的非热模式，刺激了一种强大的全身性抗肿瘤 免疫反应强到足以引起远距离、非消融肿瘤部位的远距离消退， 通常在传统疗法如放射或热消融中看到。组织解剖学是一种 目前正在引入临床使用;因此，必须了解其机制 组织破坏免疫刺激的基础我们的初步研究指出， 可以解释这种现象。首先，组织破坏引起亚细胞癌细胞抗原在细胞内的释放， 以保持其免疫原性完整性的方式。第二，组织破坏诱导癌细胞经历 细胞自杀的特定途径称为坏死性凋亡-一种吸引炎症和免疫的死亡途径 注意力，有效地启动免疫系统识别癌症抗原。接下来是一个进行式 CD8 + T细胞浸润到远处肿瘤中，伴随着另一种癌细胞死亡途径， 铁凋亡-最近发现的死亡途径是免疫治疗引发的关键机制， CD8 + T细胞杀死癌细胞。 在这个提议中，我们将追溯这些步骤，以了解组织破坏术如何发挥其异常强大的作用。 免疫效果。首先，我们将定量地微调引起组织空化的组织破坏的参数， 最大免疫原性肿瘤抗原释放。接下来，我们将重点关注坏死性凋亡的早期诱导， 确定这是否是一个必要的局部前兆事件，随后的组织破坏表现 免疫刺激依赖。然后，我们将研究CD8 + T细胞驱动的铁凋亡的后期过程， 确定这是否是组织摧毁术的远距离远位效应的介导机制。最后我们 将利用从这些研究中获得的机制见解来开发和测试潜在的临床前 组织破坏对肿瘤抗原释放、坏死性凋亡和铁凋亡的影响可能是 最大化用于癌症免疫治疗。我们组建了一个多学科团队，拥有FUS方面的专业知识， 免疫学和癌症免疫疗法来从事这项工作，这有望揭示见解和策略， 将癌症免疫疗法的影响带给更广泛的需要治愈的患者。

PROJECT SUMMARY/ABSTRACT Immunotherapy can be highly effective against cancers that elicit some recognition from the immune system (e.g., melanoma), but it remains ineffectual against cancers that are largely invisible to immune detection (e.g., pancreatic cancer). Advances in cancer immunotherapy will require interventions that can make cancers more apparent to the immune system. A growing body of evidence suggests that focused ultrasound (FUS) tumor ablation could be that intervention. By non-invasively disrupting cancer cells, thermal and mechanical modes of FUS have been shown to trigger surprisingly potent immune responses against tumors. We have found that histotripsy, a non-thermal mode of mechanical FUS, stimulates a powerful and systemic anti-tumor immune response strong enough to cause abscopal regression of distant, non-ablated tumor sites – effects not generally seen with traditional therapies like radiation or thermal ablation. Histotripsy is a technology that is presently being introduced into clinical use; therefore, it will be imperative to understand the mechanistic underpinnings of histotripsy immunostimulation. Our preliminary studies point to a stepwise series of events that may explain this phenomenon. First, histotripsy causes the release of subcellular cancer cell antigens in a manner that preserves their immunogenic integrity. Second, histotripsy induces cancer cells to undergo a specific pathway of cellular suicide called necroptosis – a death pathway that attracts inflammation and immune attention, effectively priming the immune system to recognize cancer antigens. What follows is a progressive infiltration of CD8+ T cells into distant tumors that is accompanied by another pathway of cancer cell death called ferroptosis – a death pathway recently discovered to be the critical mechanism by which immunotherapy-primed CD8+ T cells kill cancer cells. In this proposal, we will retrace these steps to understand how histotripsy exerts its unusually potent immune effects. First, we will quantitatively fine-tune the parameters of histotripsy tissue cavitation that cause maximally immunogenic tumor antigen release. Next, we will focus on the early induction of necroptosis to determine if this is a necessary local precursor event on which later manifestations of histotripsy immunostimulation depend. Then, we will examine the later process of CD8+ T cell-driven ferroptosis to determine if this is the mechanism by which the distant, abscopal effects of histotripsy are mediated. Finally, we will leverage mechanistic insights gained from these investigations to develop and test potential preclinical strategies with which the effects of histotripsy on tumor antigen release, necroptosis, and ferroptosis could be maximized for cancer immunotherapy. We have assembled a multidisciplinary team with expertise in FUS, immunology and cancer immunotherapy to pursue this work, which promises to reveal insights and strategies to bring the impact of cancer immunotherapy to a wider range of patients in need of cure.