Strasser Katharina, Birnleitner Hanna, Beer Andrea, Pils Dietmar, Gerner Marlene C, Schmetterer Klaus G, Bachleitner-Hofmann Thomas, Stift Anton, Bergmann Michael, Oehler Rudolf
Department of Surgery and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
CBmed GmbH - Center for Biomarker Research in Medicine, Graz, Austria.
Oncoimmunology. 2018 Nov 5;8(2):e1537693. doi: 10.1080/2162402X.2018.1537693. eCollection 2019.
T cells in colorectal cancer (CRC) are associated with improved survival. However, checkpoint immunotherapies antagonizing the suppression of these cells are ineffective in the great majority of patients. To better understand the immune cell regulation in CRC, we compared tumor-associated T lymphocytes and macrophages to the immune cell infiltrate of normal mucosa. Human colorectal tumor specimen and tumor-distant normal mucosa tissues of the same patients were collected. Phenotypes and functionality of tissue-derived T cells and macrophages were characterized using immunohistochemistry, RNA in situ hybridization, and multiparameter flow cytometry. CRC contained significantly higher numbers of potentially immunosuppressive CD39 and Helios-expressing regulatory T cells in comparison to normal mucosa. Surprisingly, we found a concomitant increase of pro-inflammatory IFNγ -producing T cells. PD-L1 stromal cells were decreased in the tumor tissue. Macrophages in the tumor compared to tumor-distant normal tissue appear to have an altered phenotype, identified by HLA-DR, CD14, CX3CR1, and CD64, and tolerogenic CD206 macrophages are quantitatively reduced. The prognostic effect of these observed differences between distant mucosa and tumor tissue on the overall survival was examined using gene expression data of 298 CRC patients. The combined gene expression of increased FOXP3, IFNγ, CD14, and decreased CD206 correlated with a poor prognosis in CRC patients. These data reveal that the CRC microenvironment promotes the coexistence of seemingly antagonistic suppressive and pro-inflammatory immune responses and might provide an explanation why a blockade of the PD1/PD-L1 axis is ineffective in CRC. This should be taken into account when designing novel treatment strategies.
结直肠癌（CRC）中的T细胞与生存率提高相关。然而，拮抗这些细胞抑制作用的检查点免疫疗法在绝大多数患者中无效。为了更好地理解CRC中的免疫细胞调节，我们将肿瘤相关T淋巴细胞和巨噬细胞与正常黏膜的免疫细胞浸润进行了比较。收集了同一患者的人大肠肿瘤标本和肿瘤远处的正常黏膜组织。使用免疫组织化学、RNA原位杂交和多参数流式细胞术对组织来源的T细胞和巨噬细胞的表型及功能进行了表征。与正常黏膜相比，CRC中潜在免疫抑制性CD39和表达Helios的调节性T细胞数量显著更高。令人惊讶的是，我们发现产生促炎IFNγ的T细胞也随之增加。肿瘤组织中PD-L1基质细胞减少。与肿瘤远处的正常组织相比，肿瘤中的巨噬细胞似乎具有改变的表型，通过HLA-DR、CD14、CX3CR1和CD64鉴定，且耐受性CD206巨噬细胞数量减少。利用298例CRC患者的基因表达数据，研究了远处黏膜与肿瘤组织之间这些观察到的差异对总生存期的预后影响。FOXP3、IFNγ、CD14增加以及CD206减少的联合基因表达与CRC患者的不良预后相关。这些数据表明，CRC微环境促进了看似拮抗的抑制性和促炎性免疫反应的共存，这可能解释了为什么PD1/PD-L1轴阻断在CRC中无效。在设计新的治疗策略时应考虑到这一点。
