全身放射治疗对宫颈癌荷瘤小鼠肿瘤微环境免疫细胞诱导协同刺激分子及其配体的影响

Effects of whole body radiotherapy on ICOS and ICOSL of immune cell of tumor micro-environmental of tumor-bearing mice with U14

目的:探究全身放射治疗对宫颈癌荷瘤小鼠肿瘤微环境免疫细胞可诱导协同刺激分子(ICOS)及其配体(ICOSL)的影响。方法:选取45只BALB/c小鼠,采用数表法随机将其分为对照组、模型组和放疗组,每组15只。对照组不进行治疗;模型组和放疗组小鼠给予皮下注射宫颈癌细胞株建立荷瘤裸鼠模型,建模后第4 d行全身放射治疗。分别在建模后第4 d、6 d、8 d、10 d和12 d检测肿瘤体积,建模后第12 d检测免疫细胞水平。使用Westernblot和qRT-PCR检测ICOS、ICOSL蛋白和信使核糖核酸(mRNA)的水平。结果:模型组小鼠的肿瘤体积随着建模时间的延长显著升高,与对照组相比差异有统计学意义(F=129.625,P=0.000);在建模后第6 d、8 d、10 d和12 d,放疗组小鼠的肿瘤体积显著低于模型组,差异有统计学意义(F=56.405,P=0.000);模型组的基质金属蛋白酶2(MMP2蛋白)水平显著高于对照组(F=2.461,P=0.000)、基质金属蛋白酶9(MMP9蛋白)水平也显著高于对照组,差异有统计学意义(F=0.393,P=0.000);放疗组的MMP2和MMP9mRNA水平显著低于模型组,差异有统计学意义(F=1.590,F=0.601;P=0.000);放疗组小鼠的Th1细胞比例显著高于模型组,而Treg和Th2细胞比例显著低于模型组,差异有统计学意义(F=2.427,F=3.349,F=9.951;P=0.000);模型组小鼠的ICOS和ICOSL的水平显著高于对照组,差异有统计学意义(F=2.837,F=3.576;P=0.000);放疗组小鼠的ICOS和ICOSL的mRNA水平显著低于模型组,差异有统计学意义(F=0.793,F=3.750;P=0.000)。结论:全身放射治疗可有效的抑制宫颈癌荷瘤小鼠肿瘤组织的生长,并可下调MMP2和MMP9表达水平,抑制ICOS及ICOSL表达水平,下调Treg细胞和Th2细胞的比例,从而解除免疫逃逸起到抑瘤作用。

Objective: To investigate the effects of whole body radiotherapy on ICOS and ICOSL of immune cells of tumor micro-environmental of tumor-bearing mice with U14. Methods: Forty-five BALB/c mice were selected and they were randomly divided into control group(n=15), model group(n=15) and radiotherapy group(n=15). The tumorbearing nude mouse model was established in model group and radiotherapy group by subcutaneous injection of U14 cell strain, respectively. Whole body radiotherapy was implemented on the 4 th day after model was established. The tumor volume of each mouse was measured at the 4 th d, 6 th d, 8 th d, 10 th d and 12 th d after model was established, respectively. And the immunocyte level of each mouse was detected at the 12 th d after model was established. The protein levels and mRNA level of ICOS and ICOSL were detected by using Western blot and qRT-PCR. Results: The results showed that the tumor volume of model group increased significantly with the prolonging of time, and the difference of tumor volume between model group and control group was significant(F=129.625, P<0.001). At the 6 th d, 8 th d, 10 th d and 12 th d after model was established, the tumor volume of radiotherapy group was significantly lower than that of model group(F=56.405, P<0.001), respectively. And the levels of matrix metalloproteinase 2(MMP2) and MMP9 of model group were significantly higher than those of control group(F=2.461, F=0.393, P<0.001), respectively. And the mRNA levels of MMP2 and MMP9 of radiotherapy group were significantly lower than those of model group(F=1.590, F=0.601, P<0.001), respectively. And the proportion of Th1 cell of radiotherapy group was significantly higher than that of model group and the proportions of Treg and Th2 cell were significantly lower than those of model group(F=2.427, F=3.349, F=9.951, P<0.001), respectively. And the levels of ICOS and ICOSL of model group were significantly higher than those of control group(F=2.837, F=3.576, P<0.001), respectively. Besides, the mRNA levels of ICOS and ICOSL of radiotherapy group were significantly lower than those of model group(F=0.793, F=3.750, P<0.001), respectively. Conclusion: Whole body radiotherapy can effectively inhibit the growth of tumor tissues of tumor-bearing nude mice with U14. And it can down-regulate the expression levels of MMP2 and MMP9, and can down-regulate the proportion of Treg cells and Th2 cells by inhibiting the expression level of ICOS and ICOSL, thus it can relieve the immune escape and play the effect of inhibiting tumor.