miRNA-520b and miR-520e sensitize breast cancer cells to complement attack via directly targeting 3′UTR of CD46
miRNA-520b and miR-520e sensitize breast cancer cells to complement attack via directly targeting 3′UTR of CD46
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DOI：
10.4161/cbt.10.3.12277
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发表时间：
2010-08
影响因子：
3.6
通讯作者：
Wenjing Cui;Yiwen Zhang;Nan Hu;Changliang Shan;Shuai Zhang;Weiying Zhang;Xiao-dong Zhang;L. Ye
中科院分区：
文献类型：
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作者：
Wenjing Cui;Yiwen Zhang;Nan Hu;Changliang Shan;Shuai Zhang;Weiying Zhang;Xiao-dong Zhang;L. Ye
MicroRNAs(MiRNAs)是一种非编码的RNAs，起着转录后基因调节的作用，在癌症的发展中发挥着关键作用。在本研究中，我们阐明了miR-520B和miR-520E在乳腺癌细胞中的作用。我们检测了miR-520B和miR-520E在永生化乳腺细胞系HBL-100和三种乳腺癌细胞系McF-7、LM-MCF-7和MDA-MB-231中的表达水平。我们发现miR-520B和miR-520E在乳腺癌细胞系中的表达水平低于HBL-100细胞。此外，乳腺癌细胞株对补体依赖性细胞毒(CDC)的敏感性较低。我们发现，miR-520B和miR-520E的过表达增加了乳腺癌细胞对CDC的敏感性，而进一步抑制miR-520B和miR-520E则降低了乳腺癌细胞对CDC的敏感性。我们随后证明miR-520B和miR-520E能够直接靶向膜结合补体调节蛋白CD46的3‘非翻译区(3’UTR)，这表明miR-520B和miR-520E在转录后水平下调CD46。酶联免疫吸附试验(ELISA)显示，miR-520B和miR-520E的过表达导致C3b的表达增加，这是通过下调CD46来实现的。这些结果表明，miRNA-520B和miR-520E介导的CD46下调通过另一种途径诱导癌细胞调亡，从而导致补体激活。因此，我们认为miR-520B和miR-520E通过直接靶向CD46的3‘非编码区参与了乳腺癌细胞的CDC。
MicroRNAs (miRNAs), non-coding RNAs that function as post-transcriptional gene regulators, play a pivotal role in cancer development. In the present study, we elucidated the roles of miR-520b and miR-520e in breast cancer cells. We examined the expression levels of miR-520b and miR-520e in the immortalized breast cell line, HBL-100, and in three breast cancer cell lines: MCF-7, LM-MCF-7 and MDA-MB-231. We show the expression levels of miR-520b and miR-520e in the breast cancer cell lines were lower than that in the HBL-100 cells. Furthermore, the breast cancer cell lines showed less sensitivity to complement-dependent cytotoxicity (CDC). We found that overexpression of miR-520b and miR-520e increases the sensitivity of the breast cancer cells to CDC, whereas further suppression of miR-520b and miR-520e decreases the sensitivity of the breast cancer cells to CDC. We then demonstrate that miR-520b and miR-520e are able to directly target the 3′untranslated regions (3′UTR) of the membrane-bound complement regulatory protein CD46; suggesting that miR-520b and miR-520e down-regulate CD46 at post-transcriptional level. Enzyme-linked immunosorbent assay (ELISA) showed that overexpression of miR-520b and miR-520e results in the increased expression of C3b, which is mediated by downregulated CD46. These results suggest that miRNA-520b and miR-520e mediated down-regulation of CD46 induces opsonization of cancer cells via an alternative pathway resulting in complement activation. Thus, we conclude that miR-520b and miR-520e contribute to CDC in breast cancer cells via directly targeting the 3′UTR of CD46.