Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are heterogeneous malignancies that arise from complex cellular interactions within the tissue microenvironment. Here, we sought to decipher tumor-derived signals from the surrounding microenvironment by applying digital spatial profiling (DSP) to hormone-secreting and non-functional GEP-NETs. By combining this approach with in vitro studies of human-derived organoids, we demonstrated the convergence of cell autonomous immune and pro-inflammatory proteins that suggests their role in neuroendocrine differentiation and tumorigenesis. DSP was used to evaluate the expression of 40 neural- and immune-related proteins in surgically resected duodenal and pancreatic NETs (n = 20) primarily consisting of gastrinomas (18/20). A total of 279 regions of interest were examined between tumors, adjacent normal and abnormal-appearing epithelium, and the surrounding stroma. The results were stratified by tissue type and multiple endocrine neoplasia I (MEN1) status, whereas protein expression was validated by immunohistochemistry (IHC). A tumor immune cell autonomous inflammatory signature was further evaluated by IHC and RNAscope, while functional pro-inflammatory signaling was confirmed using patient-derived duodenal organoids. Gastrin-secreting and non-functional pancreatic NETs showed a higher abundance of immune cell markers and immune infiltrate compared with duodenal gastrinomas. Compared with non-MEN1 tumors, MEN1 gastrinomas and preneoplastic lesions showed strong immune exclusion and upregulated expression of neuropathological proteins. Despite a paucity of immune cells, duodenal gastrinomas expressed the pro-inflammatory and pro-neural factor IL-17B. Treatment of human duodenal organoids with IL-17B activated NF-κB and STAT3 signaling and induced the expression of neuroendocrine markers. In conclusion, multiplexed spatial protein analysis identified tissue-specific neuro-immune signatures in GEP-NETs. Duodenal gastrinomas are characterized by an immunologically cold microenvironment that permits cellular reprogramming and neoplastic transformation of the preneoplastic epithelium. Moreover, duodenal gastrinomas cell autonomously express immune and pro-inflammatory factors, including tumor-derived IL-17B, that stimulate the neuroendocrine phenotype. © 2024 The Pathological Society of Great Britain and Ireland.

中文翻译：

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空间分析揭示胃肠胰神经内分泌肿瘤中组织特异性神经免疫相互作用

胃肠胰神经内分泌肿瘤（GEP-NET）是一种异质性恶性肿瘤，由组织微环境内复杂的细胞相互作用引起。在这里，我们试图通过将数字空间分析（DSP）应用于激素分泌和非功能性 GEP-NET 来破译来自周围微环境的肿瘤衍生信号。通过将这种方法与人源类器官的体外研究相结合，我们证明了细胞自主免疫和促炎蛋白的融合，这表明它们在神经内分泌分化和肿瘤发生中的作用。DSP 用于评估手术切除的十二指肠和胰腺 NET（n  = 20）中 40 种神经和免疫相关蛋白的表达，主要由胃泌素瘤组成（18/20）。总共检查了肿瘤、邻近的正常和异常上皮以及周围基质之间的 279 个感兴趣区域。结果按组织类型和多发性内分泌肿瘤 I (MEN1) 状态进行分层，而蛋白质表达则通过免疫组织化学 (IHC) 进行验证。通过 IHC 和 RNAscope 进一步评估了肿瘤免疫细胞自主炎症信号，同时使用患者来源的十二指肠类器官证实了功能性促炎症信号传导。与十二指肠胃泌素瘤相比，胃泌素分泌和非功能性胰腺 NET 显示出更高丰度的免疫细胞标记物和免疫浸润。与非 MEN1 肿瘤相比，MEN1 胃泌素瘤和癌前病变表现出强烈的免疫排斥和神经病理蛋白表达上调。尽管缺乏免疫细胞，十二指肠胃泌素瘤仍表达促炎和促神经因子 IL-17B。用 IL-17B 处理人十二指肠类器官可激活 NF-κB 和 STAT3 信号传导并诱导神经内分泌标志物的表达。总之，多重空间蛋白质分析识别了 GEP-NET 中的组织特异性神经免疫特征。十二指肠胃泌素瘤的特点是免疫冷微环境，允许细胞重编程和癌前上皮的肿瘤转化。此外，十二指肠胃泌素瘤细胞自主表达免疫和促炎因子，包括肿瘤源性 IL-17B，可刺激神经内分泌表型。© 2024 大不列颠及爱尔兰病理学会。