MicroRNA-34b and MicroRNA-34c are targets of p53 and cooperate in control of cell proliferation and adhesion-independent growth
MicroRNA-34b and MicroRNA-34c are targets of p53 and cooperate in control of cell proliferation and adhesion-independent growth
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DOI：
10.1158/0008-5472.can-07-1585
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发表时间：
2007-09-15
期刊：
影响因子：
11.2
通讯作者：
Nikitin, Alexander Yu.
中科院分区：
文献类型：
--
作者：
Corney, David C.;Flesken-Nikitin, Andrea;Nikitin, Alexander Yu.
MicroRNA（miRNA）是近年来发现的一类负调控基因表达的非编码RNA。最近的证据表明，miRNAs可能在癌症中发挥重要作用。然而，其在肿瘤转化中的失调机制才刚刚开始被理解。为了阐明抑癌基因p53在调节miRNA中的作用，我们分析了原代小鼠卵巢表面上皮细胞中p53条件性失活后miRNA微阵列表达谱的变化。其中受影响最显著的是miR-34 b和miR-34 c，根据定量逆转录PCR分析，它们下调了12倍。对mir-34 b/mir-34 c基因座的启动子分析表明，在miRNA编码序列上游3 kb处存在进化上保守的p53结合位点。与进化保守性一致，mir-34 b/mir-34 c在p53缺失的人卵巢癌细胞中也下调。此外，正如p53与mir-34 b/c启动子结合所预期的那样，多柔比星处理野生型而非p53缺陷型细胞导致mir-34 b/ mir-34 c表达增加。重要的是，miR-34 b和miR-34 c在抑制肿瘤性上皮卵巢细胞的增殖和软琼脂集落形成中合作，与其预测的靶点的部分重叠谱一致。总之，这些结果表明存在一种新的机制，通过这种机制，p53抑制肿瘤生长的细胞增殖和粘附非依赖性集落形成等关键成分。
MicroRNAs (miRNA) are a recently discovered class of non-coding RNAs that negatively regulate gene expression. Recent evidence indicates that miRNAs may play an important role in cancer. However, the mechanism of their deregulation in neoplastic transformation has only begun to be understood. To elucidate the role of tumor suppressor p53 in regulation of miRNAs, we have analyzed changes in miRNA microarray expression profile immediately after conditional inactivation of p53 in primary mouse ovarian surface epithelium cells. Among the most significantly affected miRNAs were miR-34b and miR-34c, which were down-regulated 12-fold according to quantitative reverse transcription-PCR analysis. Computational promoter analysis of the mir-34b/mir-34c locus identified the presence of evolutionarily conserved p53 binding sites similar to 3 kb upstream of the miRNA coding sequence. Consistent with evolutionary conservation, mir-34b/mir-34c were also down-regulated in p53-null human ovarian carcinoma cells. Furthermore, as expected from p53 binding to the mir-34b/c promoter, doxorubicin treatment of wild-type, but not p53-deficient, cells resulted in an increase of mir-34b/ mir-34c expression. Importantly, miR-34b and miR-34c cooperate in suppressing proliferation and soft-agar colony formation of neoplastic epithelial ovarian cells, in agreement with the partially overlapping spectrum of their predicted targets. Taken together, these results show the existence of a novel mechanism by which p53 suppresses such critical components of neoplastic growth as cell proliferation and adhesion-independent colony formation.