Research Laboratory of Ophthalmology and Vision Sciences, Torsten-Wiesel Research Institute of World Eye Organization, State Key Laboratory of Biotherapy, West China Hospital, SiChuan University, Chengdu, China; Department of Ophthalmology, West China Hospital, Sichuan University, Cheng Du, Sichuan, China.
West China Hospital, Sichuan University, Cheng Du, Sichuan, China.
Exp Eye Res. 2019 Apr;181:112-119. doi: 10.1016/j.exer.2019.01.005. Epub 2019 Jan 11.
The purpose of this study was to investigate indoleamine 2,3-dioxygenase 1 (IDO1) expression and its implications in uveal melanoma (UM). Bioinformatics analysis was performed on microarray data (GSE22138 and GSE27831) from the Gene Expression Omnibus (GEO) database to evaluate IDO1 expression in mRNA level. Ninety-two cases in the database were divided into the IDO1-high group (46 cases) and IDO1-low group (46 cases). Paraffin embedded tumor sections from 27 patients with UM were studied by immunofluorescence. The mRNA results showed that IDO1 expression was inversely correlated with tumor thickness (9.93 ± 3.33 mm in IDO1-high group vs. 11.56 ± 2.38 mm in IDO1-low group) (p = 0.016) and metastatic rate (30.4% in IDO1-high group vs. 69.6% in IDO1-low group, p < 0.001). The IDO1-high group showed higher immune cell gene expression: CD3D (6.56 ± 1.0 vs. 5.46 ± 0.53, p < 0.0001), CD4 (4.72 ± 0.4 vs. 4.2 ± 0.42, p < 0.0001), and CD68 (6.17 ± 1.23 vs. 5.53 ± 0.77, p = 0.015). Further analysis showed that immune-suppressive T regulatory cell genes (CD3D, CD4, IL2RA and FOXP3) were expressed in 67.4% (31/46) cases in the IDO1-high group and 23.91% (11/46) cases in the IDO1-low group. In addition, IDO1 and interferon gamma (IFNG) mRNA expression were strongly correlated (r = 0.70, p < 0.0001). The correlation analysis of different immune checkpoints showed that IDO1 was positively correlated with CD274(PDL1), but not CTLA4 or PDCD1.The disease-free survival (DFS) in the IDO1-high/IFNG-high group was better than that of the IDO1-low/IFNG-low group. The IDO1 immunostaining result showed that 2 cases in 18 UMs with Bruch's membrane (BM) rupture and 7 out of 9 cases without BM rupture were scored high (Grade 2-3) (p = 0.001). Comparing the immune cells staining results between IDO1-high group and IDO1-low group, higher percentage of patients in the former group had high levels of T cells and macrophages infiltration, but only the difference in macrophage was statistically significant (CD68, 77.78% vs. 27.78%, p = 0.04). The analysis based on GEO data and the result from immunostaining study are consistent with each other. In conclusion, the expression of IDO1 is probably induced by IFNγ from infiltrated immune cells in UM. BM rupture is an important indicator of IDO1 expression level and distribution pattern. The complex role of IDO1 may limit its therapeutic effect in UM.
本研究旨在探讨吲哚胺 2,3-双加氧酶 1（IDO1）在葡萄膜黑色素瘤（UM）中的表达及其意义。我们对来自基因表达综合数据库（GEO）的微阵列数据（GSE22138 和 GSE27831）进行了生物信息学分析，以评估 IDO1 在 mRNA 水平上的表达。数据库中的 92 例病例分为 IDO1 高表达组（46 例）和 IDO1 低表达组（46 例）。通过免疫荧光法研究了 27 例 UM 患者的石蜡包埋肿瘤切片。mRNA 结果显示，IDO1 表达与肿瘤厚度呈负相关（IDO1 高表达组为 9.93±3.33mm，IDO1 低表达组为 11.56±2.38mm）（p=0.016），与转移率呈负相关（IDO1 高表达组为 30.4%，IDO1 低表达组为 69.6%，p<0.001）。IDO1 高表达组的免疫细胞基因表达更高：CD3D（6.56±1.0 与 5.46±0.53，p<0.0001）、CD4（4.72±0.4 与 4.2±0.42，p<0.0001）和 CD68（6.17±1.23 与 5.53±0.77，p=0.015）。进一步分析显示，免疫抑制性 T 调节细胞基因（CD3D、CD4、IL2RA 和 FOXP3）在 IDO1 高表达组的 67.4%（31/46）病例和 IDO1 低表达组的 23.91%（11/46）病例中表达。此外，IDO1 和干扰素 γ（IFNG）mRNA 表达呈强相关性（r=0.70，p<0.0001）。不同免疫检查点的相关性分析显示，IDO1 与 CD274（PDL1）呈正相关，但与 CTLA4 或 PDCD1 无关。IDO1 高表达/IFNG 高表达组的无病生存率（DFS）优于 IDO1 低表达/IFNG 低表达组。IDO1 免疫染色结果显示，18 例存在布鲁赫膜（BM）破裂的 UM 中有 2 例和 9 例无 BM 破裂的 UM 中有 7 例评分较高（2-3 级）（p=0.001）。比较 IDO1 高表达组和 IDO1 低表达组的免疫细胞染色结果，前者有更高比例的患者存在 T 细胞和巨噬细胞浸润，但是只有巨噬细胞的差异有统计学意义（CD68，77.78%与 27.78%，p=0.04）。基于 GEO 数据的分析和免疫组化研究的结果是一致的。总之，IDO1 的表达可能是由浸润的免疫细胞中的 IFNγ 诱导的。BM 破裂是 IDO1 表达水平和分布模式的一个重要指标。IDO1 的复杂作用可能限制了其在 UM 中的治疗效果。
