甘草苷对胃癌荷瘤小鼠免疫功能的调节作用及机制研究

Regulation effects and mechanism of liquiritin on immune function in gastric cancer-bearing mice

目的基于Janus激酶2(JAK2)/信号转导及转录激活蛋白3(STAT3)信号通路研究甘草苷(LIQ)对胃癌荷瘤小鼠免疫功能的调节作用及机制。方法皮下注射胃癌细胞MFC建立小鼠胃癌荷瘤模型,将造模成功的小鼠分为模型组(Model组)、低剂量LIQ组(LIQ-L组,20 mg/kg)、高剂量LIQ组(LIQ-H组,40 mg/kg)、高剂量LIQ+JAK2激活剂香豆霉素A1组(LIQ-H+香豆霉素A1组,40 mg/kg LIQ+1 mg/kg香豆霉素A1),每组12只;另取12只不造模小鼠设为正常组(Normal组)。各组小鼠灌胃/腹腔注射相应药物或生理盐水,每日给药1次,连续14 d。末次给药后,测定小鼠胃癌肿瘤的体积、质量以及脏器指数;检测外周血中CD4+、CD8+T淋巴细胞百分率;观察胃癌肿瘤组织病理形态学变化;检测胃癌肿瘤组织中JAK2/STAT3信号通路相关蛋白和白细胞介素6(IL-6)蛋白表达水平。结果与Normal组相比,Model组小鼠胸腺指数、脾脏指数、外周血中CD8+T淋巴细胞百分率均显著升高(P<0.05),外周血中CD4+T淋巴细胞百分率显著降低(P<0.05)。与Model组相比,LIQ-L组、LIQ-H组小鼠上述指标均显著逆转(P<0.05),胃癌肿瘤的体积、质量以及肿瘤组织中JAK2、STAT3蛋白的磷酸化水平和IL-6蛋白的表达水平均显著降低(P<0.05),且LIQ的作用具有剂量依赖性(P<0.05);肿瘤组织细胞出现不同程度的排列疏松、空泡化、分布不均匀等情况。加入JAK2激活剂香豆霉素A1减弱了LIQ对胃癌荷瘤小鼠免疫功能的改善作用和对胃癌肿瘤的抑制作用(P<0.05)。结论LIQ可通过抑制JAK2/STAT3信号通路,改善胃癌荷瘤小鼠的免疫功能,从而发挥抗肿瘤作用。

OBJECTIVE To study the regulation effects and mechanism of liquiritin(LIQ)on immune function in gastric cancer-bearing mice based on the Janus kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3)pathway.METHODS Gastric cancer cells MFC were injected subcutaneously to establish gastric cancer-bearing model of mice.The model mice were divided into model group,LIQ low-dose group(LIQ-L group,20 mg/kg),LIQ high-dose group(LIQ-H group,40 mg/kg),and high-dose LIQ+JAK2 activator coumermycin A1 group(LIQ-H+coumermycin A1 group,40 mg/kg LIQ+1 mg/kg coumermycin A1),with 12 mice in each group.Another 12 mice without modeling were set as normal group.Mice in each group were given the corresponding drug or normal saline by intragastric administration/intraperitoneal injection,once a day,for consecutive 14 days.After the last administration,the volume and mass of gastric cancer tumor and organ index were measured.The percentages of CD4+and CD8+T lymphocytes were detected in peripheral blood.The histopathological morphology of gastric cancer tumor tissues was observed,and the expression levels of JAK2/STAT3 signaling pathway-related proteins and interleukin-6(IL-6)protein in gastric cancer tumor tissues were detected.RESULTS Compared with the normal group,the thymus index,spleen index,and the percentage of CD8+T lymphocyte in the peripheral blood of mice were obviously increased in model group(P<0.05),while the percentage of CD4+T lymphocyte in the peripheral blood were decreased(P<0.05).Compared with model group,the above indexes in LIQ-L group and LIQ-H group were significantly reversed(P<0.05),while the volume and mass of gastric cancer tumor,the phosphorylation levels of JAK2 and STAT3 protein and the expression level of IL-6 protein were significantly decreased in tumor tissue(P<0.05),and the effect of LIQ was in a dose-dependent manner(P<0.05);the tumor cells showed varying degrees of loose arrangement,vacuolization,and uneven distribution.JAK2 activator coumermycin A1 weakened the improvement effect of LIQ on the immune function of gastric cancer-bearing mice and its inhibitory effect on gastric cancer tumors(P<0.05).CONCLUSIONS LIQ can improve the immune function of gastric cancer-bearing mice by inhibiting the activation of JAK2/STAT3 signaling pathway,thus playing an anti-tumor role.