Gharagozloo M, Kalantari H, Rezaei A, Maracy M R, Salehi M, Bahador A, Hassannejad N, Narimani M, Sanei M H, Bayat B, Ghazanfari H
Bratisl Lek Listy. 2015;116(5):296-301. doi: 10.4149/bll_2015_056.
Natural killer (NK) cells play important roles in the immune defense against tumors such as colorectal cancer. In humans, NKG2D is an activating immune receptor constitutively expressed in most cytotoxic lymphocytes including NK and CD8+ T cells. In this study, the expression of NKG2D molecule was investigated in peripheral blood NK cells from colorectal cancer patients and compared with healthy subjects.
We studied 21 non-metastatic (low-grade), 17 non-metastatic (high-grade), 16 metastatic colorectal cancer patients, and 24 healthy controls. Peripheral blood samples were obtained to isolate peripheral blood mononuclear cells (PBMCs) and the percentage of peripheral blood NKG2D+CD3-CD56+ NK cells was analyzed by flow cytometry. The expression of NKG2D at mRNA level was also measured by real-time PCR in both, patients and control subjects.
The results showed a significant reduction in the percentage of NKG2D+NK cells as well as NKG2D mRNA expression in peripheral blood of metastatic colon cancer patients.
This result suggests that decreased expression of activating NKG2D receptor in metastatic colorectal cancer might compromise NK cell function and allow tumor to evade immunity (Tab. 3, Fig. 4, Ref. 33).
自然杀伤（NK）细胞在针对结直肠癌等肿瘤的免疫防御中发挥重要作用。在人类中，NKG2D是一种激活型免疫受体，在包括NK细胞和CD8 + T细胞在内的大多数细胞毒性淋巴细胞中组成性表达。在本研究中，研究了结直肠癌患者外周血NK细胞中NKG2D分子的表达，并与健康受试者进行比较。
我们研究了21例非转移性（低级别）、17例非转移性（高级别）、16例转移性结直肠癌患者以及24例健康对照。采集外周血样本以分离外周血单个核细胞（PBMC），并通过流式细胞术分析外周血NKG2D + CD3 - CD56 + NK细胞的百分比。还通过实时PCR在患者和对照受试者中测量了NKG2D在mRNA水平的表达。
结果显示，转移性结肠癌患者外周血中NKG2D + NK细胞的百分比以及NKG2D mRNA表达显著降低。
该结果表明，转移性结直肠癌中激活型NKG2D受体表达的降低可能会损害NK细胞功能，并使肿瘤逃避免疫（表3，图4，参考文献33）。
