存活素反义寡核苷酸在人甲状腺髓样癌裸鼠模型中的抑瘤作用

INHIBITORY EFFECTS OF SURVIVIN ANTISENSE OLIGODEOXYRIBONUCLEOTIDE ON HUMAN MEDULLARY THYROID CANCER INOCULATED INTO NUDE MICE

目的探讨存活素(survivin)反义寡核苷酸(antisense oligodeoxyribonucleotide,ASODN)在人甲状腺髓样癌裸鼠模型中的抑瘤作用。方法构建12只人甲状腺髓样癌裸鼠模型,随机分配到正常组,SODN(sense oligodeoxyribonucleotide,正义寡核苷酸)组和ASODN组,每组4只。各组每日一次瘤内注射相应处理液,连续7d。治疗结束后1周,杀死全部瘤鼠,切取瘤体,测算瘤重和抑瘤率以评价肿瘤生长情况,瘤组织石腊切片分别行HE、免疫组化(IHC)和DNA末端原位标记法(TUNEL法)染色以评价组织病理构造、survivin与VEGF蛋白表达和细胞凋亡的变化。结果HE染色显示ASODN组具有明显减低的血管新生特点。此外,相对于正常组和SODN组,ASODN组具有显著的survivin和VEGF低表达、高凋亡、低瘤重和高抑瘤率特点(各P<0.01),而正常组与SODN组间未见上述各特点的统计学差异。结论本研究证实针对人甲状腺髓样癌survivin基因沉默治疗能够达到明显抑瘤效果,此效果至少部分通过促进肿瘤调亡和抑制肿瘤血管新生而实现。这提示survivin基因在人甲状腺髓样癌中具有重要意义和其可成为人甲状腺髓样癌基因靶向沉默治疗的重要候选基因之一。

Objective To evaluate the inhibitory effects of survivin antisense oligodcoxyribonucleotide （ASODN） on human medullary thyroid cancer （MTC） inoculated into the nude mouse. Methods Twelve nude mouse models bearing human MTC were constructed and randomly assigned to normal group, SODN （sense oligodeoxyribonucleotide） group and ASODN group. Each group has four nude mice and was given an intratumoral injection with serum-free F12 or corresponding transfection medium every day for seven days. All nude mice were sacrificed one week after treament; tumors were fully resected from each mouse and measured for tumor weight and inhibitory rate fIR） of tumor growth; paraffin sections of each tumor were made, and respectively stained with HE, immunohistochemical or Tdt-mediated dUTP nick end labeling （TUNEL） method to evaluate the variations of histopathological construction, survivin and VEGF protein expressions, and apoptosis. Results HE staining results showed an obviously depressed angiogenic trait in the ASODN group. Compared with normal or SODN group, ASODN group possessed significant traits of lower tumor weight, higher IR, lower expression of survivin and VEGF protein, and higher apoptosis （each P〈0. 01）, but no significant difference was found between normal group and - SODN group in these traits （each P〉0. 05）. Conclusion Our study demonstrates that survivin targeting genetic silence therapy could achieve significant inhibitory effect on tumor growth in human MTC, at least in part by promoting tumor apoptosis and inhibiting tumor angiogenesis. This indicates that survivin gene plays an important role in human MTC, and may be considered one of the important backup genes for gene targeting silence therapy of human MTC.