三氧化二砷联合放疗对口腔癌移植瘤小鼠治疗作用的研究

Combination therapeutic effect with arsenic trioxide and radiation in oral squamous carcinoma cells xenografted mice model

目的观察三氧化二砷(As2O3)和低剂量放疗联合应用对口腔鳞癌裸鼠移植瘤模型的治疗作用。方法将人口腔鳞癌细胞株Tca8113接种于24只裸鼠后腿皮下,建立裸鼠移植瘤模型;随机分为4组:对照(A)组、As2O3(B)组、放疗(C)组和As2O3放疗联合治疗(D)组,每组6只。自肿瘤接种后6d开始:B组和D组腹腔内注射As2O3;C组和D组接受放射治疗;A组腹腔注射生理盐水。停药一周后处死动物,测量瘤块体积,计算肿瘤生长抑制率,采用免疫组织化学法检测各组标本中增殖相关蛋白Ki-67、凋亡相关蛋白Cleaved Caspase-3、血管内皮损伤标志物von Willebrand Factor(vWF)的表达情况,计数阳性细胞数及微血管密度(microvessel density,MVD)并进行统计学分析。结果 C、D组的移植瘤体积显著低于A组(P<0.05),D组与B、C组相比亦有显著降低(P<0.05)。B、C、D组移植瘤生长抑制率分别为20%、57%、82%。免疫组化结果显示:D组中Ki-67在的表达及MVD值明显低于其他三组,Cleaved Caspase-3的表达显著高于其他三组,统计学均有显著性差异(P<0.01);与A组相比,B、C、D组Ki-67、Cleaved Caspase-3的表达以及MVD值均有显著性差异(P<0.001)。结论 As2O3能够提高放疗对口腔鳞癌细胞裸鼠移植瘤的治疗作用,其抗肿瘤作用的可能机制为抑制肿瘤细胞增殖和血管生成及诱导肿瘤细胞凋亡。

Objective To investigate the therapeutic effect of arsenic trioxide （As2O3） and radiation therapy on oral squamous carcinoma cells xenografted mouse model. Methods 24 BALB/c nude mice were divided into 4 groups in random：group A as the control,group B with As2O3 treatment group C with radiation treatment,and group D with the radiation and As2O3 combination treatment,. Cancer cells （Tca8113） were inoculated into the hind leg s.c of mice. On day 6,single dose of radiation （7.5Gy） was give to group C and D. As2O3 was administrated i.p. in a dose of 5mg/kg twice a week for 3 consecutive weeks to the groups B and D,starting from 6th day of tumor inoculation. The mice were sacrificed after stopping the treatment for 1 week and tumors were removed. The tumor size was measured using a metric scale caliper and then fixed in neural formalin for histopathological examinations. The expression of Ki-67,Cleaved Caspase-3 and von Willebrand Factor in the tissue were detected by immunohistochemistry. Results Compared with the control group,the tumor volumes were significantly decrease in group C and D （P〈0.05）. The tumor volumes in group B and C were significantly higher than those in group D （P〈0.05）. The inhibitory rate （tumor volume） was 82% in group D,57% in group C and 20% in group B. Immunohistochemistry staining of tumor tissue revealed that the expression levels of Ki-67 and microvessel density（MVD） were decreased in group B and C,especially noticeably decrease in group D compared with controls（P〈0.001）. The tumor sections of group B and C showed increased expression of Cleaved Caspase-3 respectively,whereas higher level of Cleaved Caspase-3 was found more frequently in the combination treatment than in other three groups （P〈0.001）. Conclusions As2O3 could enhance the therapeutic efficacy of low dose radiation treatment on oral squamous carcinoma cell Tca8113 xenografted model. It revealed the possible mechanism of anti-tumor effect of As2O3 by inhibiting tumor cells proliferation and angiogenesis and inducing apoptosis in tumor cells.