头颈癌中突变型 TP53 破坏 TP63-miR-27a* 反馈环路。

Disruption of TP63-miR-27a* Feedback Loop by Mutant TP53 in Head and Neck Cancer.

机构信息

Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX.

Department of Experimental Therapeutics and The Center for RNA Interference and Non-Coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, TX.

出版信息

J Natl Cancer Inst. 2020 Mar 1;112(3):266-277. doi: 10.1093/jnci/djz097.

DOI:10.1093/jnci/djz097

PMID:31124563

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7073912/

Abstract

BACKGROUND

Alterations in the epidermal growth factor receptor and PI3K pathways in head and neck squamous cell carcinomas (HNSCCs) are frequent events that promote tumor progression. Ectopic expression of the epidermal growth factor receptor-targeting microRNA (miR), miR-27a* (miR-27a-5p), inhibits tumor growth. We sought to identify mechanisms mediating repression of miR-27a* in HNSCC, which have not been previously identified.

METHODS

We quantified miR-27a* in 47 oral cavity squamous cell carcinoma patient samples along with analysis of miR-27a* in 73 oropharyngeal and 66 human papillomavirus-positive (HPV+) samples from The Cancer Genome Atlas. In vivo and in vitro TP53 models engineered to express mutant TP53, along with promoter analysis using chromatin immunoprecipitation and luciferase assays, were used to identify the role of TP53 and TP63 in miR-27a* transcription. An HNSCC cell line engineered to conditionally express miR-27a* was used in vitro to determine effects of miR-27a* on target genes and tumor cells.

RESULTS

miR-27a* expression was repressed in 47 oral cavity tumor samples vs matched normal tissue (mean log2 difference = -0.023, 95% confidence interval = -0.044 to -0.002; two-sided paired t test, P = .03), and low miR-27a* levels were associated with poor survival in HPV+ and oropharyngeal HNSCC samples. Binding of ΔNp63α to the promoter led to an upregulation of miR-27a*. In vitro and in vivo findings showed that mutant TP53 represses the miR-27a* promoter, downregulating miR-27a* levels. ΔNp63α and nucleoporin 62, a protein involved in ΔNP63α transport, were validated as novel targets of miR-27a*.

CONCLUSION

Our results characterize a negative feedback loop between TP63 and miR-27a*. Genetic alterations in TP53, a frequent event in HNSCC, disrupt this regulatory loop by repressing miR-27a* expression, promoting tumor survival.

摘要

背景

表皮生长因子受体和 PI3K 通路在头颈部鳞状细胞癌（HNSCC）中的改变是促进肿瘤进展的常见事件。表皮生长因子受体靶向 microRNA（miR），miR-27a*（miR-27a-5p）的异位表达抑制肿瘤生长。我们试图确定以前未确定的 HNSCC 中抑制 miR-27a*的机制。

方法

我们对 47 例口腔鳞状细胞癌患者样本中的 miR-27a进行了定量分析，并对 The Cancer Genome Atlas 中的 73 例口咽癌和 66 例 HPV 阳性（HPV+）样本进行了 miR-27a分析。使用体内和体外工程化表达突变型 TP53 的 TP53 模型，以及使用染色质免疫沉淀和荧光素酶测定进行启动子分析，以确定 TP53 和 TP63 在 miR-27a转录中的作用。我们构建了一种能够条件性表达 miR-27a的 HNSCC 细胞系，用于体外确定 miR-27a*对靶基因和肿瘤细胞的影响。

结果

与匹配的正常组织相比，47 例口腔肿瘤样本中的 miR-27a表达受到抑制（平均对数差异=-0.023，95%置信区间=-0.044 至-0.002；双侧配对 t 检验，P=0.03），并且在 HPV+和口咽 HNSCC 样本中，低水平的 miR-27a与不良预后相关。ΔNp63α与启动子结合导致 miR-27a上调。体内和体外研究结果表明，突变型 TP53 抑制 miR-27a启动子，下调 miR-27a水平。ΔNp63α和核孔蛋白 62（一种参与 ΔNP63α 运输的蛋白质）被验证为 miR-27a的新靶点。