Jun/miR-22/HuR 调控轴促进结直肠癌的发生。
The Jun/miR-22/HuR regulatory axis contributes to tumourigenesis in colorectal cancer.
机构信息
State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu, 210046, China.
Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, 300060, China.
出版信息
Mol Cancer. 2018 Jan 19;17(1):11. doi: 10.1186/s12943-017-0751-3.
BACKGROUND
Colorectal cancer (CRC) is a severe health problem worldwide. Clarifying the mechanisms for the deregulation of oncogenes and tumour suppressors in CRC is vital for its diagnosis, treatment, prognosis and prevention. Hu antigen R (HuR), which is highly upregulated in CRC, functions as a pivotal oncogene to promote CRC progression. However, the underlying cause of its dysregulation is poorly understood.
METHODS
In CRC tissue sample pairs, HuR protein levels were measured by Western blot and immunohistochemical (IHC) staining, respectively. HuR mRNA levels were also monitored by qRT-PCR. Combining meta-analysis and microRNA (miRNA) target prediction software, we predicted miRNAs that targeted HuR. Pull-down assay, Western blot and luciferase assay were utilized to demonstrate the direct binding of miR-22 on HuR's 3'-UTR. The biological effects of HuR and miR-22 were investigated both in vitro by CCK-8, EdU and Transwell assays and in vivo by a xenograft mice model. JASPAR and SABiosciences were used to predict transcriptional factors that could affect miR-22. Luciferase assay was used to explore the validity of putative Jun binding sites for miR-22 regulation. ChIP assay was performed to test the Jun's occupancy on the C17orf91 promoter.
RESULTS
We observed a significant upregulation of HuR in CRC tissue pairs and confirmed the oncogenic function of HuR both in vitro and in vivo. We found that an important tumour-suppressive miRNA, miR-22, was significantly downregulated in CRC tissues and inversely correlated with HuR in both CRC tissues and CRC cell lines. We demonstrated that miR-22 directly bound to the 3'-UTR of HuR and led to inhibition of HuR protein, which repressed CRC proliferation and migration in vitro and decelerated CRC xenografted tumour growth in vivo. Furthermore, we found that the onco-transcription factor Jun could inhibit the transcription of miR-22.
CONCLUSIONS
Our findings highlight the critical roles of the Jun/miR-22/HuR regulatory axis in CRC progression and may provide attractive potential targets for CRC prevention and treatment.
背景
结直肠癌（CRC）是全球范围内严重的健康问题。阐明 CRC 中癌基因和肿瘤抑制因子失调的机制对于其诊断、治疗、预后和预防至关重要。Hu 抗原 R（HuR）在 CRC 中高度上调，作为促进 CRC 进展的关键癌基因发挥作用。然而，其失调的根本原因尚不清楚。
方法
在 CRC 组织样本对中，通过 Western blot 和免疫组织化学（IHC）染色分别测量 HuR 蛋白水平。还通过 qRT-PCR 监测 HuR mRNA 水平。结合荟萃分析和 microRNA（miRNA）靶标预测软件，我们预测了靶向 HuR 的 miRNA。通过下拉实验、Western blot 和荧光素酶测定证实了 miR-22 与 HuR 3'-UTR 的直接结合。通过 CCK-8、EdU 和 Transwell 测定以及异种移植小鼠模型在体外和体内研究了 HuR 和 miR-22 的生物学效应。JASPAR 和 SABiosciences 用于预测可能影响 miR-22 的转录因子。荧光素酶测定用于探索 Jun 结合位点对 miR-22 调节的有效性。ChIP 测定用于测试 Jun 在 C17orf91 启动子上的占有率。
结果
我们观察到 CRC 组织对中 HuR 的显著上调，并在体外和体内证实了 HuR 的致癌功能。我们发现一种重要的肿瘤抑制 miRNA，miR-22，在 CRC 组织中显著下调，并且在 CRC 组织和 CRC 细胞系中与 HuR 呈负相关。我们证明 miR-22 直接结合到 HuR 的 3'-UTR，并导致 HuR 蛋白的抑制，从而抑制体外 CRC 增殖和迁移，并减缓体内 CRC 异种移植肿瘤生长。此外，我们发现癌转录因子 Jun 可以抑制 miR-22 的转录。
结论
我们的研究结果强调了 Jun/miR-22/HuR 调节轴在 CRC 进展中的关键作用，并可能为 CRC 的预防和治疗提供有吸引力的潜在靶点。
Zotero 插件