The long noncoding RNA H19 promotes tamoxifen resistance in breast cancer via autophagy
The long noncoding RNA H19 promotes tamoxifen resistance in breast cancer via autophagy
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长非编码RNA H19通过自噬促进乳腺癌他莫昔芬耐药
DOI：
10.1186/s13045-019-0747-0
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发表时间：
2019-07-24
影响因子：
28.5
通讯作者：
Zhou, Jichun
中科院分区：
文献类型：
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作者：
Wang, Ji;Xie, Shuduo;Zhou, Jichun
背景三苯氧胺耐药仍然是激素受体阳性乳腺癌的临床挑战。最近，自噬失调被认为是他莫昔芬耐药的潜在机制。虽然长的非编码RNA H19参与肿瘤发生的各个阶段，但其在他莫昔芬耐药中的作用仍然未知。在这里，我们评估了H19在他莫昔芬耐药乳腺癌的发展中的作用。MethodsQuantitative real-time PCR分析了H19在他莫昔芬耐药乳腺癌组织中的表达。H19的敲低用于评估体外和体内对他莫昔芬的敏感性。使用H19的敲低和过表达来分析自噬状态。采用实时定量甲基化特异性聚合酶链反应、染色质免疫沉淀、免疫荧光和Western blot等方法研究H19对三苯氧胺的耐药机制。结果H19在三苯氧胺耐药乳腺癌细胞系和肿瘤组织中的表达显著上调，H19的敲除增强了三苯氧胺的体内外敏感性。此外，H19的敲低显著抑制MCF 7他莫昔芬抗性（MCF 7/TAMR）细胞中的自噬。相反，H19的过表达促进自噬。有趣的是，H19在MCF 7他莫昔芬敏感细胞中的过表达可以重现他莫昔芬抗性。此外，在MCF 7/TAMR-shH 19细胞中观察到Beclin 1启动子区域甲基化的增加。在双敲除组中，shH 19 +shSAHH和shH 19 + shDNMT 3B都挽救了Beclin 1启动子区域甲基化水平并重新激活自噬功能。染色质免疫沉淀试验进一步验证，DNMT 3B结合到Beclin 1启动子区域和敲低H19增加这种binding.ConclusionsOur研究结果表明，H19诱导自噬激活通过H19/SAHH/DNMT 3B轴，这可能有助于他莫昔芬耐药乳腺癌。
BackgroundTamoxifen resistance remains a clinical challenge for hormone receptor-positive breast cancer. Recently, dysregulations in autophagy have been suggested as a potential mechanism for tamoxifen resistance. Although the long noncoding RNA H19 is involved in various stages of tumorigenesis, its role in tamoxifen resistance remains unknown. Here, we assessed the role of H19 in the development of tamoxifen-resistant breast cancer.MethodsQuantitative real-time PCR analyzed expression of H19 in tamoxifen-resistant breast cancer tissues. Knockdown of H19 was used to assess the sensitivity to tamoxifen in vitro and in vivo. Both knockdown and overexpression of H19 were used to analyze the status of autophagy. Real-time quantitative methylation-specific polymerase chain reaction, chromatin immunoprecipitation, immunofluorescence, and Western blot were used to explore the tamoxifen resistance mechanism of H19.ResultsIn this study, we observed that the expression of H19 was substantially upregulated in tamoxifen-resistant breast cancer cell line and tumor tissues, and knockdown of H19 enhanced the sensitivity to tamoxifen both in vitro and in vivo. Furthermore, knockdown of H19 significantly inhibited autophagy in MCF7 tamoxifen-resistant (MCF7/TAMR) cells. Conversely, overexpression of H19 promoted autophagy. Interestingly, overexpression of H19 in MCF7 tamoxifen-sensitive cells could recapitulate tamoxifen resistance. Moreover, an increase in methylation in the promoter region of Beclin1 was observed in MCF7/TAMR-shH19 cells. In the double knockdown groups, both shH19+shSAHH and shH19+shDNMT3B rescued the Beclin1 promoter region methylation levels and reactivated autophagy functions. A chromatin immunoprecipitation assay further validated that DNMT3B binds to the Beclin1 promoter region and the knockdown of H19 increases this binding.ConclusionsOur findings demonstrate that H19 induces autophagy activation via the H19/SAHH/DNMT3B axis, which could contribute to tamoxifen resistance in breast cancer.