Over 20% of cancer 'driver' genes encode chromatin regulators. Long noncoding RNAs (lincRNAs), which are dysregulated in various cancers, play a critical role in chromatin dynamics and gene regulation by interacting with key epigenetic regulators. It has been previously reported that the lincRNA HOTAIR mediates recruitment of polycomb repressive complex 2 (PRC2) leading to aberrant transcriptional silencing of tumor suppressor genes in glioma and breast cancer. Thus, lincRNA HOTAIR can serve as a promising therapeutic target. Herein, we identified a small-molecule compound AC1Q3QWB (AQB) as a selective and efficient disruptor of HOTAIR-EZH2 interaction, resulting in blocking of PRC2 recruitment and increasing tumor suppressors expression. Molecular docking and high-throughput screening were performed to identify the small compound, AQB. RIP and ChIRP assays were carried to assess the selective interference of AQB with the HOTAIR-EZH2 interaction. The effects of AQB on tumor malignancy were evaluated in a variety of cancer cell lines and orthotopic breast cancer models. The combination therapy of AQB and 3-Deazaneplanocin A (DZNep), an inhibitor of the histone methyltransferase EZH2 was used and in orthotopic breast cancer and glioblastoma patient-derived xenograft (PDX) models. Tumor cells highly expressing HOTAIR and EZH2 were sensitive to AQB. APC2, as one of the target genes, was significantly up-regulated by AQB and led to degradation of β-catenin resulting in suppression of Wnt/β-catenin signaling which may contribute to inhibition of tumor growth and metastasis and in orthotopic breast cancer models. Remarkably, AQB enhanced the toxicity of DZNep . In orthotopic breast cancer and glioblastoma patient-derived xenografts (PDX) models, the combination of low doses of AQB and DZNep realized much better killing than DZNep treatment alone. AQB is a HOTAIR-EZH2 inhibitor, which blocks PRC2 recruitment and has great potential as an effective agent for targeted cancer therapy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6643429 | PMC |
http://dx.doi.org/10.7150/thno.35188 | DOI Listing |
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