Long non-coding RNA UCA1 enhances tamoxifen resistance in breast cancer cells through a miR-18a-HIF1α feedback regulatory loop

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• 作者：Xiunan Li ; Yumei Wu ; Aihui Liu ; Xin Tang
• 关键词：Breast cancer ; UCA1 ; miR ; 18a ; Endocrine resistance ; HIF1α
• 刊名：Tumor Biology
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：37
• 期：11
• 页码：14733-14743
• 全文大小：
• 刊物主题：Cancer Research;
• 出版者：Springer Netherlands
• ISSN：1423-0380
• 卷排序：37

文摘

Recent studies reported that long non-coding RNAs (lncRNAs) might play critical roles in regulating endocrine resistance of breast cancer. Urothelial carcinoma-associated 1 (UCA1) is an lncRNA with an oncogenic role in breast cancer. This study aimed to investigate whether UCA1 is involved in acquired tamoxifen resistance in estrogen receptor (ER)-positive cancer cells. Our findings reveal that tamoxifen induces UCA1 upregulation in ER-positive breast cancer cells in a HIF1α-dependent manner. UCA1 upregulation results in significantly enhanced tamoxifen resistance. The upregulated UCA1 sponges miR-18a, which is a negative regulator of HIF1α. Therefore, UCA1 upregulation is further enhanced through a miR-18a-HIF1α feedback loop. In addition, our data also showed that miR-18a is a modulator of tamoxifen sensitivity due to its regulative effect on cell cycle proteins. miR-18a inhibitor reduced the sensitivity of MCF-7 cells to tamoxifen, while miR-18a mimics sensitized BT474 cells to tamoxifen. Therefore, miR-18a downregulation also partly contributes to acquired tamoxifen resistance in the cancer cells. These findings provide some useful information for future clinical treatment of tamoxifen resistance.