干扰素-γ上调结直肠癌细胞系CEA表达的实验研究

Effect of different concentration of interferon-γon CEA expression of colorectal cancer cells

背景与目的放射免疫治疗中肿瘤摄取标记抗体的量与肿瘤细胞靶位分子的表达量密切相关。本研究探讨不同浓度IFN-γ对结直肠癌细胞系CEA的诱导效应,以选择最适IFN-γ浓度上调结直肠癌细胞系CEA的表达及提高对131I-CL3结合率。方法取对数生长期结直肠癌细胞系LOVO和LS175T,实验组以终浓度为10、100、500、1000U/ml的IFN-γ诱导培养48h,对照组加入等量不含IFN-γ的培养液。各组2种细胞CEA的表达率及平均荧光强度(MFI)采用流式细胞仪(FACS)检测。结合法测定2种细胞诱导前后对131I-CL3的结合量(Ncpm)及结合率(BR)。细胞CEA表达率、MFI和BR的差异采用One-wayANOVA检验。结果LOVO与LS175T细胞CEA基础表达率分别为(75.6±6.8)%及(92.7±9.1)%,IFN-γ浓度在100U/ml以下时,LOVO细胞(F=2.689,P>0.05)及LS175T细胞(F=2.107,P>0.05)的CEA表达率均未见显著性增高。当IFN-γ浓度为500U/ml时,LOVO细胞CEA表达率(t=3.244,P<0.05)及LS175T细胞MFI(t=5.810,P<0.005)比对照组显著提高。IFN-γ浓度为500U/ml和1000U/ml两组之间,LOVO细胞CEA表达率(t=0.389,P>0.05)及LS175T细胞CEA表达率(t=0.113,P>0.05)未见显著差异。131I-CL3在LOVO与LS175T细胞的基础结合率分别为(22.1±2.4)%与(32.3±4.9)%。诱导后LOVO细胞增幅明显,倍增比(MR)为1.05～2.25倍,LS175T为1.11～1.56倍。在IFN-γ浓度为500U/ml时,LS175T细胞(t=4.988,P<0.01)及LOVO细胞(t=9.262,P<0.001)对131I-CL3的结合率均显著提高。结论IFN-γ可以上调结直肠癌细胞系CEA的表达,在一定范围内IFN-γ浓度与CEA表达率及对131I-CL3的结合量存在相关性。

Background Objective In radioimmunotherapy,the quantity of molecular targets is stongly associated with the binding of radiolabelled antibody.Here we reported the effect of different concentration of interferon-γ on CEA expression of colorectal cancer cells.Methods The cell lines,LOVO and LS175T,in logarithmic growth phase,were cultured in the presence of 10,100,500 and 1000 U/ml interferon-γ for 48 hours.The corresponding controls encountered no interferon-γ.Cell surface expression rate and mean fluorescence intensity（MFI）of CEA on cell lines were tested by FACS.The binding rate（BR）and net radiocounts per minute（Ncpm）of ^131I-CL3 on cells were measured by non-competetive saturation analysis.The indices such as expression rate,MFI and BR were compared between each groups with different concentration of interferon-γ by One-way ANOVA test.Results The basal expression rates of CEA on LOVO and LS175T were（75.6±6.8）%and（92.7±9.1）%,respectively.When IFN-γ was below 100 U/ml,the expression rate of CEA on LOVO（F=2.689,P〉0.05）and LS175T（F=2.107,P〉0.05）showed no significant increase compared with the control group.However,when IFN-γ was above 500 U/ml,the expression rate was significantly increased in LOVO（t=3.244,P〈0.05）and in LS175T（t=5.810,P〈0.005）.As to CEA expression rate,no significant difference was found between 500 U/ml and 1 000 U/ml（P〉0.05）.The basal binding rate of ^131 ICL3 on LOVO and LS175T was（22.1±2.4）%and（32.3±4.9）%,respectively.By the induction of IFN-γ,the binding rate of 131I-CL3 on LOVO and LS175T was increased by 1.05-2.25 times and 1.11-1.56 times,respectively.When IFN-γ was above 500U/ml,the binding rate was significantly increased in LOVO（t=9.262,P〈0.001）and in LS175T（t=4.988,P〈0.01）.Conclusion Interferon-γ can up-regulate CEA expression and increase the binding of ^131I-CL3 in colorectal cancer cells.There is a correlation between the induction effect and concentration of IFN-γ.