在肿瘤治疗领域，传统疗法如放疗和化疗等的疗效往往受限于凋亡耐受，亟需寻求肿瘤新型治疗策略以改善治疗效果。近年研究表明，肿瘤的细胞焦亡疗法不仅可以实现癌细胞的高效杀伤还能有效激活适应性免疫，该疗法已被证明是一种高效的肿瘤治疗策略。随着细胞焦亡的发生机理与相关分子通路的阐明，研究者们已开发出多种策略激活细胞焦亡用于肿瘤治疗。

其中凋亡/焦亡（Caspase-3/GSDME）信号通路的发现为细胞凋亡向细胞焦亡的转化提供了理论基础。基于上述通路，研究者们提出利用化疗实现细胞焦亡的诱导。然而，细胞焦亡本身是一种病理性死亡过程，化疗引起细胞焦亡的非特异性激活可能会导致严重的全身副作用，如系统性炎症、脓毒症和多器官衰竭等。因此，精准激活细胞焦亡十分重要。而化疗作为一种系统性疗法，并非诱导细胞焦亡的首选方案。相对化疗，以光、声和磁等外源能量为激发源的局部疗法具有非侵入性、低全身毒性和高时空选择性的优势，是激活细胞焦亡的理想途径。但目前所开发的局部激活焦亡疗法往往缺乏靶向性，且忽视了影像引导的重要性，难以满足精准激活细胞焦亡的需求。同时，若把肿瘤当成单独的器官看待，过多肿瘤细胞发生细胞焦亡造成大量细胞因子进入血液循环有可能引发全身性炎症反应。因此，亟需构建出程度可调谐的焦亡诱导策略用于肿瘤治疗。此外，免疫浸润差同样是限制焦亡疗法疗效的主要因素，迫切需要改善免疫浸润来放大细胞焦亡介导的抗肿瘤免疫效应。针对上述肿瘤焦亡治疗相关领域关键问题，本论文以局部引发策略为核心开展新型细胞焦亡诱导方案的探索，具体的研究内容如下：

首先，针对当前局部激活焦亡疗法缺乏靶向性和影像学引导的问题，本论文开发了靶向U87MG脑胶质瘤的近红外二区（NIR-II）荧光引导的光热诊疗剂用于细胞焦亡的诱导。本论文选择半导体聚合物（PS）为发光材料，介孔二氧化硅为外壳构建出具备NIR-II发光性能和优良光热性质的纳米粒子，并通过共价偶联方式为该纳米粒子进行聚乙二醇和cRGD靶向肽修饰以实现较长的在体循环和高效的脑胶质瘤靶向。本论文所构建的纳米诊疗剂PSiPR具有稳定的光学性质和深层在体NIR-II荧光成像性能，对比无靶向修饰的纳米粒子，本论文构建的靶向纳米诊疗剂PSiPR对脑胶质瘤靶向性能可提高3倍以上，且能实现原位脑胶质瘤的透颅成像。同时，PSiPR可在体外高效诱导U87MG细胞发生细胞焦亡，且在体治疗效果优异。该研究为光热激活细胞焦亡提供了范例，为后续细胞焦亡的可控激活提供了新视角。

随后，为了实现局部可控的细胞焦亡激活，本论文利用结直肠癌特有的高H₂S微环境开发了一种肿瘤原位激活的NIR-II光热前药型焦亡纳米转换器CUPIT。这种H₂S-光的二元开关赋予焦亡介导的肿瘤治疗更高的时空可控特性。本论文成功阐明了以光热温度为单一变量的温度-细胞焦亡程度之间的内在关系，并初步探究了肿瘤区域发生不同程度焦亡所导致的小鼠全身病理学特征改变。在系统探究焦亡程度与病理学表征的关系之后，本论文验证了细胞焦亡在抗肿瘤免疫中的作用。在CT26荷瘤小鼠模型中，细胞焦亡诱发了强大的抗肿瘤免疫，根除原发肿瘤并诱导免疫记忆效应，并联合免疫检查点抑制剂疗法实现了对远端肿瘤的完全缓解，大幅延长了荷瘤小鼠的生存期。该研究实现了焦亡程度的可调谐性，为可控激活细胞焦亡用于肿瘤治疗提供了新思路。

最后，针对恶性肿瘤免疫浸润差的问题，本论文选用穿透深度更深的超声波为焦亡激发端以满足大部分深处肿瘤病灶，并通过消耗构成细胞外基质（ECM）的主要成分I型胶原来破除T细胞浸润的物理屏障，增强细胞焦亡疗法的疗效。本论文成功合成了具备声敏剂性质的金属有机框架（MOF）并利用MOF的载体性质搭载了LY364947以抑制I型胶原的分泌，进而重塑ECM。随后，对合成的MOF进行红细胞膜包覆以增强血液循环能力。体外实验结果表明，该策略构建的声动力免疫调节剂LPM能有效诱导地西他滨预处理的三阴性乳腺癌细胞系4T1发生细胞焦亡。在体实验结果表明，LPM实现了强大的焦亡诱导和ECM重塑作用，几乎实现了原位瘤的根除且形成强烈的免疫记忆效应，对再次接种的癌细胞也产生了强烈的抑制作用，复发率降低80%。这种基于超声波诱导的联合疗法不仅拓宽了用于抗肿瘤治疗的临床应用场景，也为细胞焦亡诱导剂有潜力作为肿瘤原位疫苗的假设提供了有力佐证。

Apoptosis tolerance limits the efficacy of conventional cancer therapies. Recent studies have shown that pyroptosis can not only kill cancer cells efficiently but also activate adaptive immunity, which has been proven to be more effective in tumor treatment. With the elucidation of the mechanism of pyroptosis and related molecular pathways, researchers have developed a variety of strategies to activate pyroptosis for tumor therapy.

Apoptosis/pyroptosis (Caspase-3/GSDME) signaling pathway provides a possibility for transforming apoptosis to pyroptosis. Based on this pathway, chemotherapy were first used for the induction of pyroptosis. However, pyroptosis is a pathological death process, and the nonspecific activation of pyroptosis may lead to severe systemic side effects, such as systemic inflammation, sepsis, and multiorgan failure. Pyroptosis therefore requires accurate activation. Compared to chemotherapy, local therapies with exogenous energy such as light, sound, and magnetism have the advantages of non-invasive, low systemic toxicity, and high spatial and temporal selectivity, and are an ideal way to activate cell pyroptosis. Presently, local pyroptosis therapies omit the importance of imaging guidance and lack targeting, making it difficult to precisely initiate pyroptosis. Meanwhile， considering the tumor as a single organ, excessive pyroptosis of tumor cells may lead to a large number of cytokines entering the blood circulation, causing systemic inflammation. Therefore, it is urgent to construct a pyroptosis inducer with adjustable degree for tumor treatment. In addition, poor immune infiltration is also a major factor limiting the efficacy of pyroptosis therapy, and there is an urgent need to improve the immune infiltration to amplify the anti-tumor immune effect mediated by cell pyroptosis. To address these problems, we developed several new methods of pyroptosis induction based on local treatment. The specific research contents are shown as follows:

First, in response to the lack of targeting and imaging guidance of locally activated pyroptosis therapy, we developed near-infrared region II (NIR-II) fluorescence-guided photothermal treatment agents targeting U87MG glioma for the induction of pyroptosis. In this paper, polymer semiconductor (PS) was selected as the luminescent material, mesoporous silica as the shell to build nanoparticles with NIR-II luminescence properties and excellent photothermal properties, and polyethylene glycol and cRGD were modified to achieve long systemic circulation and efficient glioma targeting. The nanotherapeutic agent PSiPR constructed in this paper has stable optical properties and deep NIR-II fluorescence imaging performance. Compared with the nanoparticles without targeted modification, the targeted nanotherapeutic agent PSiPR can improve the targeting performance of glioma by more than 3 times, and can realize in situ transcranial imaging of glioma. Meanwhile, PSiPR can efficiently induce pyroptosis under 808nm laser irradiation in U87MG cells, and shows excellent therapeutic effect in vivo. This study provides a paradigm for photoheat-activated pyroptosis and provides new insights into controllable activation of pyroptosis.

Subsequently, to achieve locally controlled pyroptosis activation in tumor site, we have developed an in situ activated NIR-II photothermal pyroptosis nano-converter CUPIT for the unique high H₂S microenvironment of colorectal cancer. This binary switch of H₂S-light conferred higher spatiotemporal controllable properties to pyroptosis-mediated tumor therapy. In this study, we successfully defined a functional mapping between the temperature and the degree of pyroptosis with photothermal temperature as a single variable, and initially explored the altered systemic pathological features of the mice caused by different degrees of pyroptosis in the tumor region. After systematically study of the relationship between the degree of pyroptosis and pathological characterization, we verify the role of pyroptosis in anti-tumor immunity. In a CT26 tumor-bearing mouse model, pyroptosis induced robust anti-tumor immunity, eradicated the primary tumor and induced immune memory effects, and combined with immune checkpoint inhibitor therapy achieved a complete remission of distant tumors, which greatly prolonged the survival of tumor-bearing mice. This study realized the tunability of the degree of pyroptosis, which provides a new idea for controllable activated cell pyroptosis for tumor treatment.

Finally, in view of the heterogeneity of tumor and poor immune infiltration, ultrasound was chosen as the pyroptosis trigger to meet most of the deep tumor lesions, and through the consumption of extracellular matrix (ECM) to break the physical barrier of T cell infiltration, enhance the curative effect of pyroptosis therapy. In vitro results showed that our strategy effectively induced pyroptosis in 4T1 model upon pretreatment with decitabine. The in vivo results showed that our strategy achieves robust pyroptosis induction and ECM removal. This strategy achieved tumor eradication and formed a so strong immune memory effect that strongly inhibited the re-challenged cancer cells, and reduced the recurrence rate by 80%. This combination therapy not only broadens the clinical application for antitumor therapy, but also provides evidence for the tumor cell pyroptosis as in situ vaccines.