Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, INSERM UMR1138, Centre de Recherche des Cordeliers, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy, Villejuif, France.
Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, INSERM UMR1138, Centre de Recherche des Cordeliers, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy, Villejuif, France; Université Paris Sud, Paris Saclay, Faculty of Medicine, Kremlin Bicêtre, France; Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Methods Cell Biol. 2022;172:99-114. doi: 10.1016/bs.mcb.2021.12.027. Epub 2022 Jan 20.
The exposure of calreticulin (CALR) on the cell surface of apoptotic cancer cells is an important "eat-me" signal that stimulates the engulfment by antigen presenting cells (APCs). When cells are exposed to immunogenic cell death (ICD) inducers, CALR translocates from the lumen of the endoplasmic reticulum (ER) to the cell surface, where it serves as a ligand for LDL-receptor-related protein 1 (LRP1, also known as CD91) expressed by dendritic cells (DCs). Surface-exposed CALR facilitates tumor antigen transfer to DCs and in turn antigen cross-presentation to cytotoxic T cells, altogether culminating in the activation of adaptive immune responses. Consistent with its role as an apical signaling event in anticancer immunity, blocking or neutralizing CALR abolishes the immune-dependent anticancer efficacy of a variety of ICD inducing anticancer agents. Recently we showed that saturating CALR receptors on DCs with abundant recombinant CALR protein, or soluble CALR secreted from cancer cells decreases the potency of ICD-mediated antitumor immune responses. Here we detail how to harness an artificially inducible release of soluble CALR from engineered cancer cells, which can blind DCs from recognizing immunogenic cancer cells, resulting in reduced anticancer immunity. This system offers precise control over the release of immunosuppressive soluble CALR, thus yielding a useful tool for the validation of ICD-inducing immunotherapies.
细胞表面钙网蛋白（CALR）的暴露是凋亡癌细胞的一个重要“吃我”信号，可刺激抗原呈递细胞（APCs）吞噬。当细胞暴露于免疫原性细胞死亡（ICD）诱导剂时，CALR 从内质网（ER）腔移位到细胞表面，在那里它作为树突状细胞（DC）表达的 LDL 受体相关蛋白 1（LRP1，也称为 CD91）的配体。表面暴露的 CALR 有助于将肿瘤抗原转移到 DC，并反过来将抗原交叉呈递给细胞毒性 T 细胞，最终导致适应性免疫反应的激活。与其作为抗癌免疫中顶端信号事件的作用一致，阻断或中和 CALR 会消除各种诱导 ICD 的抗癌药物的免疫依赖性抗癌功效。最近我们表明，用丰富的重组 CALR 蛋白或癌细胞分泌的可溶性 CALR 饱和 DC 上的 CALR 受体，会降低 ICD 介导的抗肿瘤免疫反应的效力。在这里，我们详细介绍了如何利用工程化癌细胞中人工诱导的可溶性 CALR 释放，使 DC 无法识别免疫原性癌细胞，从而降低抗癌免疫力。该系统可精确控制免疫抑制性可溶性 CALR 的释放，因此是验证 ICD 诱导免疫疗法的有用工具。
