Radiation induced regulation of endothelial adhesion receptors
Radiation induced regulation of endothelial adhesion receptors
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辐射诱导的内皮粘附受体调节
DOI：
10.1096/fasebj.2020.34.s1.09424
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Herter J
中科院分区：
文献类型：
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作者：
Kiljan M;Weil S;Vásquez-Torres A;Hettich M;Reinscheid M;Ibruli O;Baues C;Marnitz S;Baus W;Herter-Sprie G;Herter J
现代免疫疗法和放射疗法的协同作用已被证明是一种有前途的抗癌策略。然而，有关这些疗法的潜在机制的基本问题尚未得到解答。虽然临床研究已经证明辐射可以潜在地促进免疫细胞浸润和肿瘤免疫原性，但临床医生的目标是利用辐射改善免疫细胞浸润并将渗透很少的所谓“冷”肿瘤转变为“热”肿瘤，直到今天还缺乏机制研究数据。我们假设肿瘤免疫细胞组成的改变是由于介导免疫细胞从血液中募集的内皮粘附受体表达的改变所致。因此，为了研究肿瘤血管内皮，我们量化了浸润的免疫细胞，并检查了不同辐射分级后内皮粘附配体的调节。我们应用了两种不同的辐射剂量：1x10Gy（被认为可以提高免疫原性的剂量）和 1x2Gy（传统/正常分割），通过流式细胞术分析免疫细胞浸润，并使用实时 PCR 和基于组织学的方法研究肿瘤和健康脉管系统中 ICAM-1、ICAM-2、VCAM-1、E-选择素和 P-选择素等内皮分子的表达。我们分析了放疗后 1 小时、4 小时、8 小时、24 小时、3 天、5 天和 8 天的 Kras;Trp53 突变小鼠的可移植肺肿瘤。重要的是，我们观察到所有组在放疗后的第一个 24 小时内组织免疫细胞普遍减少，而在放射后第 3 天细胞数量开始恢复。此外，我们发现一些内皮粘附受体的表达以剂量依赖性方式发生变化，但其他内皮粘附受体的表达不受影响。例如，两组中的 ICAM-2 均保持不变，但肿瘤血管系统显示 E-选择素在放射后第一小时内快速上调，随后下调，2-3 天后第二次增加。较低的剂量 (2Gy) 在第 3 天的 24 小时达到峰值后引起 VCAM-1 的上调增强。这一点特别令人感兴趣，因为 VCAM-1 对于 T 细胞募集至关重要，目前大多数研究表明需要高剂量来改善肿瘤免疫原性。然而，我们观察到 10Gy 后 CD4 和 CD8 T 细胞的重新增殖更加强劲，这一发现可能是由于 2Gy 剂量后 ICAM-1 显着下调，而 10Gy 后未观察到。更好地了解依赖于放射分割的内皮粘附受体调节具有治疗相关性：新型免疫检查点抑制策略需要有效地将 T 细胞招募到肿瘤中才能有效，例如，分离和改良的 T 细胞（所谓的 CAR-T 细胞）疗法也是如此：我们的结果首次表明内皮配体调节根据放射剂量而有所不同。支持或资助信息DFG（HE 6810/3-1 至 J.M.H.，HE） 6897/2-1 至 G.H.S.）和 CMMC（CAP-13 至 J.M.H. 和 CAP-16 至 G.H.S. 以及 B02 至 G.H.S. 和 J.M.H.）
The synergy of modern immunotherapeutics and radiation has proven to be a promising strategy to combat cancer. However, fundamental questions regarding the underlying mechanisms of these therapies are unanswered. While clinical studies have demonstrated that radiation can potentially boost immune cell infiltration and tumor immunogenicity, the clinicians’ aim to use radiation to improve immune cell infiltration and turn so called ‘cold’ tumors with little infiltration into ‘hot’ tumors lacks mechanistic research data until today. We hypothesize that alterations of the tumor immune cell composition result from modified endothelial adhesion receptor expression mediating immune cell recruitment from the blood. Thus, in order to investigate the tumor vascular endothelium, we quantified infiltrating immune cells and examined the regulation of endothelial adhesion ligands following different fractionations of radiation. We applied two different radiation doses: 1x10Gy (a dose thought to improve immunogenicity), and 1x2Gy (conventional/normofractionation), analyzed immune cell infiltration via flow cytometry, and investigated the expression of endothelial molecules like ICAM‐1, ICAM‐2, VCAM‐1, E‐selectin, and P‐selectin using real time PCR and histology‐based approaches in the tumor and healthy vasculature. We analyzed transplantable lung tumors ofKras;Trp53mutant mice 1h, 4h, 8h, 24h, 3d, 5d, and 8d after radiation. Importantly, we observed a generalized decrease of tissue immune cells within the first 24h with recovering populations at day 3 after radiation in all groups. Furthermore, we found that the expression of some endothelial adhesion receptors changes in a dose‐dependent manner, but others are not affected. For instance, ICAM‐2 remains unchanged in both groups, but tumor vasculature shows a rapid upregulation of E‐selectin within the first hour after radiation, followed by a downregulation and a second increase after 2–3 days. The lower fractions (2Gy) elicit an augmented upregulation of VCAM‐1 after 24h peaking at day 3. This is of particular interest as VCAM‐1 is vital to T cell recruitment and currently most research indicates that high doses are needed to improve tumor immunogenicity. However, we observed a more robust repopulation of both CD4 and CD8 T cells following 10Gy – a finding that might be due to a marked downregulation of ICAM‐1 following 2Gy doses that was not observed following 10Gy. An improved understanding of the endothelial adhesion receptor regulation depending on radiation fractionation is of therapeutic relevance: novel immune checkpoint inhibition strategies require efficient T cell recruitment to the tumor to be effective and so do, for instance, isolated and modified T cell (so called CAR‐T cell) therapies: Our results are the first to indicate that endothelial ligand regulation differs depending on radiation dose.Support or Funding InformationDFG (HE 6810/3‐1 to J.M.H., HE 6897/2‐1 to G.H.S.) and the CMMC (CAP‐13 to J.M.H. and CAP‐16 to G.H.S. as well as B02 to G.H.S. and J.M.H.)