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目的检测免疫球蛋白样转录子2(ILT2)在胃癌组织及胃癌细胞系中的表达,分析其表达与胃癌生物学行为和临床特征的关系。方法采用免疫组织化学方法检测50例胃癌病理组织中ILT2蛋白的表达,并结合临床病理指标进行分析。采用实时荧光定量PCR和FACS流式细胞术检测6株高(MKN1)、中(SGC-7901,AGS)、低(MGC-803)及未分化(HGC-27,BCG-823)人胃癌细胞株ILT2的mRNA和蛋白表达。MTT法检测自然杀伤细胞(NK-92)和外周血淋巴细胞(PBMCs)对HGC-27、MKN1两种胃癌细胞的杀伤活性。结果 50例胃癌病理组织中ILT2表达阳性率为62.0%(31/50),正常胃组织不表达ILT2。在低分化型胃癌组织中ILT2表达阳性率为73.3%(22/30),在分化型组织中表达阳性率为45%(9/20),差异有统计学意义(χ2=4.089,P<0.05);肿瘤直径>5 cm时胃癌组织中ILT2表达阳性率为84.2%(16/19),明显高于肿瘤<5 cm时患者阳性率48.4%(15/31),差异有统计学意义(χ2=6.417,P<0.01)。6株人胃癌细胞均表达ILT2,ILT2在低分化和未分化胃癌细胞中表达阳性率高于中分化和高分化细胞(P<0.05)。在不同效靶比下人PBMC及NK-92细胞对MKN1细胞(ILT2低表达)的杀伤能力高于对HGC-27细胞(ILT2高表达)的杀伤(P<0.05)。结论胃癌组织细胞ILT2的表达与细胞分化程度和胃癌临床病理特征显著相关,PBMC和NK-92细胞对高表达ILT2的胃癌细胞的杀伤能力降低。提示ILT2可能参与肿瘤的免疫逃逸并可作为胃癌诊断和治疗的新靶点。
Objective To detect the expression of immunoglobulin-like transcript 2 (ILT2) in gastric cancer and gastric cancer cell lines, and analyze the relationship between its expression and biological behavior and clinical characteristics of gastric cancer. Methods Immunohistochemical method was used to detect the expression of ILT2 protein in 50 cases of gastric cancer, combined with clinicopathological parameters. Six high (MKN1), medium (SGC-7901, AGS), low (MGC-803) and undifferentiated (HGC-27, BCG-823) human gastric cancer cell lines were detected by real-time fluorescence quantitative PCR and FACS flow cytometry. ILT2 mRNA and protein expression. The killing activity of natural killer cells (NK-92) and peripheral blood lymphocytes (PBMCs) on HGC-27 and MKN1 gastric cancer cells was measured by MTT assay. Results The positive rate of ILT2 expression in 50 cases of gastric cancer was 62.0% (31/50). Normal gastric tissue did not express ILT2. The positive rate of ILT2 expression in poorly differentiated gastric cancer tissues was 73.3% (22/30), and the positive rate in differentiated tissues was 45% (9/20). The difference was statistically significant (χ2=4.089, P<0.05). The positive rate of ILT2 expression in gastric cancer tissues was 84.2% (16/19) when the tumor diameter was >5 cm, which was significantly higher than that of 48.4% (15/31) when the tumor was <5 cm. The difference was statistically significant (χ2). = 6.417, P < 0.01). Six human gastric cancer cells expressed ILT2, and the positive rate of ILT2 expression in poorly differentiated and undifferentiated gastric cancer cells was higher than that of moderately differentiated and highly differentiated cells (P<0.05). The killing ability of human PBMC and NK-92 cells against MKN1 cells (low expression of ILT2) was higher than that of HGC-27 cells (high expression of ILT2) under different effect ratios (P<0.05). Conclusion The expression of ILT2 in gastric cancer cells is significantly correlated with the degree of cell differentiation and the clinicopathological features of gastric cancer. The killing capacity of PBMC and NK-92 cells on gastric cancer cells with high expression of ILT2 is reduced. It suggests that ILT2 may be involved in tumor immune escape and can be used as a new target for the diagnosis and treatment of gastric cancer.