OBJECTIVE To explore the relationship between the methylation status of the promoter 5＇CpG island region and the biological behavior of human colorectal cancer RKO cells in vitro. METHODS RKO cells were treated with a selective DNA methyltransferase inhibitor-5-aza-2＇-deoxycytidine （5-aza-CdR） for 72 h. Methylationspecific PCR （MSP）, T-A cloning and DNA sequence analysis were used to determinate the 5＇CpG island methylation status of the p16/CDKN2 tumor suppressor gene. Cell growth, morphological changes and apoptosis were analyzed by the MTT assay, flow cytometry, fluorescence staining and electron microscopy. RESULTS The 5＇CpG island of the p16/CDKN2 tumor suppressor gene in RKO cells was a typically hypermethylated. The DNA methyltransferase inhibitor （5-Aza-CdR） effectively reversed the hypermethylation status of the promoter region. With demethylation, RKO cell growth was suppressed, the cells doubling times were prolonged （P〈0.01） and apoptosis was induced, which showed a relationship. CONCLUSION A selective DNA methyltransferase （DNMT） inhibitor can inhibit proliferation by demethylation in 5＇CpG islands, and may be a potential new therapy target for colorectal cancer.
目的总结胰岛素瘤的外科诊治经验。方法对13例胰岛素瘤患者的临床资料进行回顾性分析。结果本组患者均有典型的W h ipp le三联症表现,5例患者曾被误诊;术前B超、CT、选择性腹腔动脉造影、磁共振成像(MR I)的定位率分别为44%、50%、71%和33%;术中13例患者经触诊定位11例,2例经术中B超均获定位;术后12例治愈,1例死于复发。结论胰岛素瘤误诊率较高,必要的辅助检查有助于肿瘤的定位,手术方式的选择应根据肿瘤的部位、大小、数量而定,手术治疗效果良好。
