CAJ | 학술논문

目的探讨甲基转移酶抑制剂5-氮-2'脱氧胞苷(5-Aza-CdR)对小鼠大肠癌发生发展的影响及其与细胞周期依赖性激酶抑制因子p16/CDKN2 mRNA表达的关系.方法 40只雄性KM小鼠按随机数字表法随机分为2组:1,2-二甲肼(DMH)诱癌组和甲基化干预组,每组20只.小鼠皮下注射DMH 25 mg/kg,每周1次,连续22周,以诱发小鼠大肠癌,甲基化干预组于12周开始皮下注射5-Aza-CdR.另选同来源雄性KM小鼠作为未诱癌对照组(阴性对照组)10只,于皮下按25mg/kg注射生理盐水,每周1次,连续22周."席卷法"收集肿瘤组织,HE染色观察肿瘤发生的数目、类型及浸润程度;免疫组织化学染色观察细胞增殖核抗原(PCNA)蛋白表达情况;原位杂交技术检测肠癌组织抑癌基因p16/CDKN2 mRNA的表达.结果 (1)DMH诱癌组肿瘤数达(7.6±3.1)个/只,而甲基化干预组诱癌数为(3.4±1.8)个/只,且以重度异性增生为主,浸润癌的发生率明显低于DMH诱癌组(P＜0.05).(2)DMH诱癌组19只小鼠中PCNA阳性表达16只,明显多于甲基化干预组(19只中11只阳性表达)及未诱癌对照组(0只,均P＜0.05).(3)DMH诱癌组有明显p16/CDKN2 mRNA杂交信号(蓝紫色),主要位于胞质,但甲基化干预组染色显然较DMH诱癌组强,尤其以瘤灶部位明显.结论早期5-Aza-CdR的干预能显著抑制小鼠大肠癌的发生发展,其抑制肿瘤机制可能是通过激活抑制因子p16/CDKN2的表达.
목적 탐토갑기전이매억제제5-담-2'탈양포감(5-Aza-CdR)대소서대장암발생발전적영향급기여세포주기의뢰성격매억제인자p16/CDKN2 mRNA표체적관계.방법 40지웅성KM소서안수궤수자표법수궤분위2조:1,2-이갑정(DMH)유암조화갑기화간예조,매조20지.소서피하주사DMH 25 mg/kg,매주1차,련속22주,이유발소서대장암,갑기화간예조우12주개시피하주사5-Aza-CdR.령선동래원웅성KM소서작위미유암대조조(음성대조조)10지,우피하안25mg/kg주사생리염수,매주1차,련속22주."석권법"수집종류조직,HE염색관찰종류발생적수목、류형급침윤정도;면역조직화학염색관찰세포증식핵항원(PCNA)단백표체정황;원위잡교기술검측장암조직억암기인p16/CDKN2 mRNA적표체.결과 (1)DMH유암조종류수체(7.6±3.1)개/지,이갑기화간예조유암수위(3.4±1.8)개/지,차이중도이성증생위주,침윤암적발생솔명현저우DMH유암조(P＜0.05).(2)DMH유암조19지소서중PCNA양성표체16지,명현다우갑기화간예조(19지중11지양성표체)급미유암대조조(0지,균P＜0.05).(3)DMH유암조유명현p16/CDKN2 mRNA잡교신호(람자색),주요위우포질,단갑기화간예조염색현연교DMH유암조강,우기이류조부위명현.결론 조기5-Aza-CdR적간예능현저억제소서대장암적발생발전,기억제종류궤제가능시통과격활억제인자p16/CDKN2적표체.
Objective To explore the effects and relationship of specific demethylation agent 5-Aza-2'-deoxycytidine (5-Aza-CdR) on colorectal cancer ( CRC ) induced by 1,2-dimethylhydrazine ( DMH ) in mouse and the in vivo expression of cyclin-dependent kinases inhibitor p16/CDKN, mRNA. Methods A total of 40 male KM mice were randomized into 2 groups and CRC was induced by a 22-week injection of DMH. One group was interfered by specific DNA methyltransferase inhibitor 5-Aza-CdR. Another 10 the same source male KM mice were induced by a 22-week injection of saline as none induced cancer control group (negative control group ). All mice were sacrificed to examine for colorectal neoplasm.Immunohistochemical staining was used to assess the expression of proliferating cell nuclear antigen (PCNA). The expression of p16/CDKN2 mRNA was detected by in situ hybridization. Results The average numbers of neoplasm was higher in the DMH group (7. 6 ±3. 1 ) than that of the group DMH +5-Aza-CdR (3.4 ± 1.8, P ＜0. 05). Immunohistochemical staining showed there was a significant elevation of PCNA in the group DMH(16/19) as compared with that in the group DMH +5-Aza-CdR ( 11/19, P ＜0. 05 ). In situ hybridization revealed that the level of tumor suppressor gene p16/CDKN2 mRNA was significantly lower in the group DMH than that in the group DMH +5-Aza-CdR. Conclusion The specific demethylation agent 5-Aza-2'-deoxycytidine may inhibit the carcinogenesis of CRC. Its mechanism may be related with a high expression of p16/CDKN2 mRNA.