Bile Acids Increase Levels of MicroRNAs 221 and 222, Leading to Degradation of CDX2 During Esophageal Carcinogenesis
Bile Acids Increase Levels of MicroRNAs 221 and 222, Leading to Degradation of CDX2 During Esophageal Carcinogenesis
复制标题
DOI：
10.1053/j.gastro.2013.08.008
复制
发表时间：
2013-12-01
期刊：
影响因子：
29.4
通讯作者：
Hibi, Toshifumi
中科院分区：
文献类型：
--
作者：
Matsuzaki, Juntaro;Suzuki, Hidekazu;Hibi, Toshifumi
背景与目的：胆汁反流有助于巴雷特食管（BE）的发展，并可能参与其发展为食管腺癌（EAC）。我们研究了胆汁酸是否会影响microrna (MIRs) 221和222的水平或功能，它们与p27Kip1信使RNA的30-UTR结合以抑制其翻译。p27Kip1的减少增加了转录因子CDX2的降解；据报道，在BE发展为EAC的过程中，CDX2水平下降。方法：我们使用定量逆转录酶聚合酶链反应比较MIRs 221和222的水平，免疫组织化学比较11例患者BE和EAC区域的p27Kip1和CDX2蛋白的水平。我们检测了胆汁酸暴露对EAC细胞中MIRs 221、222和CDX2水平的影响。我们研究了MIRs 221和222抑制剂对NOD/SCID/IL-2R γ (null)小鼠EAC异种移植肿瘤生长的影响。结果：与BE相比，EAC区MIRs 221和222水平升高，p27Kip1和CDX2水平降低。当培养细胞暴露于胆汁酸中时，MIRs 221和222的水平升高，同时核胆汁酸受体/法内酯X受体（FXR）的活性也升高。用胆汁酸孵育细胞增加CDX2的降解；当细胞也与蛋白酶体抑制剂孵育时，这一过程减少。在培养细胞中，MIRs 221和222的过表达降低了p27Kip1和CDX2的水平，而敲低这些MIRs则增加了这些蛋白的水平。MIRs 221和222抑制剂增加了NOD/SCID/IL-2R γ (null)小鼠EAC细胞中p27Kip1和CDX2的水平，并降低了异种移植肿瘤的生长。结论：与同一患者的BE区域相比，我们观察到人EAC组织中MIRs 221和222的水平升高。我们发现食道细胞暴露于胆汁酸中激活FXR，增加MIRs 221和222的水平，降低p27Kip1的水平，促进蛋白酶体对CDX2的降解。我们的工作开辟了通过FXR拮抗剂或MIRs抑制剂作为BE和EAC治疗选择的治疗靶点。
BACKGROUND & AIMS: Bile reflux contributes to development of Barrett's esophagus (BE) and could be involved in its progression to esophageal adenocarcinoma (EAC). We investigated whether bile acids affect levels or functions of microRNAs (MIRs) 221 and 222, which bind to the 30-UTR of p27Kip1 messenger RNA to inhibit its translation. Reduced p27Kip1 increases degradation of the transcription factor CDX2; levels of CDX2 have been reported to decrease during progression of BE to EAC. METHODS: We used quantitative reverse transcriptase polymerase chain reaction to compare levels of MIRs 221 and 222 and immunohistochemistry to compare levels of p27Kip1 and CDX2 proteins in areas of BE and EAC from each of 11 patients. We examined the effects of bile acid exposure on levels of MIRs 221 and 222 and CDX2 in EAC cells. We investigated the effects of inhibitors of MIRs 221 and 222 on growth of human EAC xenograft tumors in NOD/SCID/IL-2R gamma(null) mice. RESULTS: Levels of MIRs 221 and 222 increased and levels of p27Kip1 and CDX2 decreased in areas of EAC vs BE. Levels of MIRs 221 and 222 increased, along with activity of nuclear bile acid receptor/farnesoid X receptor (FXR), when cultured cells were exposed to bile acids. Incubation of cells with bile acids increased degradation of CDX2; this process was reduced when cells were also incubated with proteasome inhibitors. Overexpression of MIRs 221 and 222 reduced levels of p27Kip1 and CDX2, and knockdown of these MIRs increased levels of these proteins in cultured cells. Inhibitors of MIRs 221 and 222 increased levels of p27Kip1 and CDX2 in EAC cells and reduced growth of xenograft tumors in NOD/SCID/IL-2R gamma(null) mice. CONCLUSIONS: We observed increased levels of MIRs 221 and 222 in human EAC tissues, compared with areas of BE from the same patient. We found that exposure of esophageal cells to bile acids activates FXR and increases levels of MIRs 221 and 222, reducing levels of p27Kip1 and promoting degradation of CDX2 by the proteasome. Our work opened the perspective of therapeutically targeting this pathway either via FXR antagonists or inhibitors of MIRs as a treatment option for BE and EAC.