Chair of Cytology, Histology and Embryology, Faculty of Medical Sciences, UNLP, Buenos Aires, Argentina.
LIAN, FLENI-CONICET, Escobar, Argentina.
BMC Cancer. 2020 Jul 3;20(1):624. doi: 10.1186/s12885-020-07113-8.
Clear cell renal cell carcinoma (ccRCC), the most aggressive renal cancer, is characterized by early lymph node metastases and bad prognosis. Most therapies targeting advanced or metastatic ccRCC are based, as first-line treatment, on the administration of the vascular endothelial growth factor (VEGF) neutralizing antibody termed Bevacizumab. Despite proven benefits, the expected results were not obtained for the majority of patients. The possibility that an intricate interplay between angiogenesis and immune-checkpoints might exist lead us to evaluate tumor angiogenesis, by means of VEGF expression together with the immune checkpoint HLA-G/ILT4.
Tumor specimens were obtained from patients from two separate cohorts: One from "Evita Pueblo" Hospital from Berazategui, (Buenos Aires, Argentina) and the second includes patients surgically operated at the Urology Department of Saint-Louis Hospital (Paris, France) with a confirmed ccRCC diagnosis. Immunohistochemistry was performed with specific antibodies directed against HLA-G, VEGF-A, VEGF-C, D240, CD34, ILT4 and Ca-IX. In addition, gene expression levels were measured in a cell line derived from a ccRCC patient by semi-quantitative RT-PCR.
Our results show that the highly vascularized tumors of ccRCC patients express high levels of VEGF and the immune-checkpoint HLA-G. In addition, ILT4, one of the HLA-G receptors, was detected on macrophages surrounding tumor cells, suggesting the generation of an immune-tolerant microenvironment that might favor tumorigenesis. Notably, RT-qPCR analysis provided the first evidence on the transcriptional relationship between HLA-G/ILT4 and the VEGF family. Namely, in the presence of HLA-G or ILT4, the levels of VEGF-A are diminished whereas those of VEGF-C are increased.
In an effort to find new therapeutic molecules and fight against metastasis dissemination associated with the poor survival rates of ccRCC patients, these findings provide the rationale for co-targeting angiogenesis and the immune checkpoint HLA-G.
透明细胞肾细胞癌（ccRCC）是最具侵袭性的肾癌，其特征为早期淋巴结转移和预后不良。大多数针对晚期或转移性 ccRCC 的治疗方法均以血管内皮生长因子（VEGF）中和抗体贝伐珠单抗作为一线治疗。尽管已证实该方法有效，但大多数患者并未获得预期的效果。血管生成和免疫检查点之间可能存在复杂的相互作用，这促使我们通过 VEGF 表达以及免疫检查点 HLA-G/ILT4 来评估肿瘤血管生成。
从两个独立的队列的患者中获取肿瘤标本：一组来自阿根廷贝拉萨特吉的“Evita Pueblo”医院，另一组包括在巴黎圣路易医院泌尿科接受手术治疗并确诊为 ccRCC 的患者。使用针对 HLA-G、VEGF-A、VEGF-C、D240、CD34、ILT4 和 Ca-IX 的特异性抗体进行免疫组织化学染色。此外，通过半定量 RT-PCR 测量了源自 ccRCC 患者的细胞系中的基因表达水平。
我们的结果表明，ccRCC 患者的高血管化肿瘤表达高水平的 VEGF 和免疫检查点 HLA-G。此外，在肿瘤细胞周围的巨噬细胞上检测到 HLA-G 的受体之一 ILT4，这表明生成了有利于肿瘤发生的免疫耐受微环境。值得注意的是，RT-qPCR 分析首次提供了 HLA-G/ILT4 与 VEGF 家族之间转录关系的证据。即在存在 HLA-G 或 ILT4 的情况下，VEGF-A 的水平降低，而 VEGF-C 的水平增加。
为了寻找新的治疗分子并对抗与 ccRCC 患者生存率低相关的转移扩散，这些发现为同时靶向血管生成和免疫检查点 HLA-G 提供了依据。
