西妥昔单抗联合伊马替尼对二甲肼诱导的结肠癌大鼠的治疗作用及机制研究

摘要

目的:研究西妥昔单抗联合伊马替尼对二甲肼诱导的结肠癌大鼠的治疗作用及其机制.方法:取36只SD大鼠随机分为模型组、西妥昔单抗组和西妥昔单抗+伊马替尼组,每组12只,于各组大鼠的颈背部皮下注射二甲肼(30 mg/kg)建立结肠癌大鼠模型.另设正常组大鼠10只.西妥昔单抗组股静脉滴注给予西妥昔单抗(400 mg/m2、250 mg/m2),西妥昔单抗+伊马替尼组股静脉滴注给予西妥昔单抗,同时灌胃给予伊马替尼(10 mg/kg).正常组与模型组大鼠给予等体积的生理盐水.给药4周后,取大鼠结肠组织,在显微镜下观察结肠组织中异变腺窝病灶(ACF)的个数,western blotting法检测结肠组织中ATP7A、磷酸化蛋白激酶B(p-Akt)、磷酸化哺乳动物雷帕霉素靶蛋白(p-mTOR)的表达量.采用酶联免疫吸附试验(ELISA)法测定大鼠血清血管皮生长因子(VEGF)含量.结果:西妥昔单抗十伊马替尼组大鼠结肠组织中ACF的数量明显少于模型组及西妥昔单抗组(P＜0.05),血清VEGF含量显著低于模型组及西妥昔单抗组(P＜0.05).与正常组相比,模型组结肠癌组织中ATP7A、p-Akt、p-mTOR蛋白表达明显上调(P＜0.05).与模型组相比,西妥昔单抗十伊马替尼组大鼠结肠癌组织中的ATP7A、p-Akt、p-mTOR蛋白水平均明显降低(P＜0.05),且西妥昔单抗十伊马替尼组低于西妥昔单抗组(P＜0.05).结论:西妥昔单抗联合伊马替尼可明显降低结肠癌大鼠血清VEGF含量,同时下调ATP7A、p-Akt、p-mTOR蛋白表达,从而影响结肠癌组织中的能量合成,抑制肿瘤细胞增殖,发挥协同增效作用.%Objective:To investigate the effect and mechanism of cetuximab combined with imatinib on dimethylhydrazine induced colon cancer in rats.Methods:46 rats were randomly divided into four groups:noral control group,model group,cetuximab group and cetuximab + imatinib group.Except for the normal group (n=10),the rats were subcutaneously injected with dimethylhydrazine (30 mg/kg) through the neck once a week for 5 weeks to establish colon cancer model.The rats in cetuximab + imatinib group were given cetuximab (400 mg/m2,250 mg/m2) via femoral intravenous injection,and 10 mg/kg imatinib via gavage.Rats in cetuximab group were given i.v.cetuximab only.The normal group and model group rats were given equal vol-ume of saline.After 4 weeks of administration,the aberrant crypt foci (ACF) in colon tissue was observed with a light microscope.The expressions of ATP7A,phosphorylated (p-) Akt and p-mammalian target of rapamycin (p-mTOR) in colon tissues were determined by western blotting.Results:The VEGF level in serum and the number of ACF in cetuximab + imatinib group were obviously lower than those in model group and cetuximab group,and the expressions of ATP7A,p-Akt and p-mTOR were significantly down-regulated (P＜ 0.05).Conclusion:The combination of cetuximab and imatinib could reduce the VEGF level and the expressions of ATP7A,p-Akt and p-mTOR in colon cancer rats,thus might influence the energy synthesis in cancer cells and inhibit tumor cell proliferation.