Key Points ICD of CT26 cells relies mainly on AH1 tumor Ag expression. AH1-deficient necroptosis remains more immunogenic compared with apoptosis. Necroptotic, but not apoptotic, CT26 cells generate immunity against neoepitopes. Visual Abstract Immunogenic cell death (ICD) occurs when a dying cell releases cytokines and damage-associated molecular patterns, acting as adjuvants, and expresses Ags that induce a specific antitumor immune response. ICD is studied mainly in the context of regulated cell death pathways, especially caspase-mediated apoptosis marked by endoplasmic reticulum stress and calreticulin exposure and, more recently, also in relation to receptor-interacting protein kinase–driven necroptosis, whereas unregulated cell death like accidental necrosis is nonimmunogenic. Importantly, the murine cancer cell lines used in ICD studies often express virally derived peptides that are recognized by the immune system as tumor-associated Ags. However, it is unknown how different cell death pathways may affect neoepitope cross-presentation and Ag recognition of cancer cells. We used a prophylactic tumor vaccination model and observed that both apoptotic and necroptotic colon carcinoma CT26 cells efficiently immunized mice against challenge with a breast cancer cell line that expresses the same immunodominant tumor Ag, AH1, but only necroptotic CT26 cells would mount an immune response against CT26-specific neoepitopes. By CRISPR/Cas9 genome editing, we knocked out AH1 and saw that only necroptotic CT26 cells were still able to protect mice against tumor challenge. Hence, in this study, we show that endogenous AH1 tumor Ag expression can mask the strength of immunogenicity induced by different cell death pathways and that upon knockout of AH1, necroptosis was more immunogenic than apoptosis in a prophylactic tumor vaccination model. This work highlights necroptosis as a possible preferred ICD form over apoptosis in the treatment of cancer.

中文翻译：

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免疫显性 AH1 抗原缺陷的坏死性凋亡，但不凋亡，鼠癌细胞诱导抗肿瘤保护

要点 CT26 细胞的ICD 主要依赖于AH1 肿瘤Ag 的表达。与细胞凋亡相比，AH1 缺陷的坏死性凋亡仍然具有更高的免疫原性。坏死性但不凋亡的 CT26 细胞产生针对新表位的免疫力。Visual Abstract 免疫原性细胞死亡 (ICD) 当垂死的细胞释放细胞因子和损伤相关的分子模式，充当佐剂，并表达诱导特定抗肿瘤免疫反应的 Ags 时，就会发生免疫原性细胞死亡 (ICD)。ICD 主要在受调节的细胞死亡途径的背景下进行研究，特别是由内质网应激和钙网蛋白暴露标记的半胱天冬酶介导的细胞凋亡，以及最近还与受体相互作用蛋白激酶驱动的坏死性凋亡有关，而不受调节的细胞死亡如意外坏死是非免疫原性的。重要的，ICD 研究中使用的鼠癌细胞系通常表达病毒衍生的肽，这些肽被免疫系统识别为肿瘤相关抗原。然而，尚不清楚不同的细胞死亡途径如何影响癌细胞的新表位交叉呈递和 Ag 识别。我们使用了一种预防性肿瘤疫苗接种模型，并观察到凋亡和坏死性结肠癌 CT26 细胞都能有效地免疫小鼠以抵抗表达相同免疫优势肿瘤 Ag AH1 的乳腺癌细胞系的攻击，但只有坏死性 CT26 细胞才会对小鼠产生免疫反应CT26 特异性新表位。通过 CRISPR/Cas9 基因组编辑，我们敲除 AH1，发现只有坏死性凋亡的 CT26 细胞仍然能够保护小鼠免受肿瘤攻击。因此，在本研究中，我们表明，内源性 AH1 肿瘤 Ag 表达可以掩盖由不同细胞死亡途径诱导的免疫原性强度，并且在预防性肿瘤疫苗接种模型中，在敲除 AH1 后，坏死性凋亡比细胞凋亡更具免疫原性。这项工作强调了坏死性凋亡是癌症治疗中可能优于细胞凋亡的 ICD 形式。