Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong.
Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
Exp Eye Res. 2018 Oct;175:142-147. doi: 10.1016/j.exer.2018.06.021. Epub 2018 Jun 19.
To confirm that mouse double minute 2 (MDM2) could inhibit p53 activity in human pterygium. And to show the disruption of MDM2-p53 interaction could reactive the functions of p53 in pterygium.
Pterygium and corresponding conjunctiva tissues were collected for establishment of primary cell lines. Expression patterns of MDM2 and p53 were detected by immunofluorescence. Protein localization of p53 and MDM2, and transcriptional activity of p53 in both untreated and MDM2 antagonist (Nutlin) treated pterygium cells were quantified.
In pterygium, p53 was highly expressed in cytoplasm and slightly expressed in the nuclei. MDM2 was localized in the nuclei. A p53 transcriptional regulated target gene, p21, was not expressed in pterygium tissues, suggesting the p53 transcriptional activity was not active in pterygium. After treatment with Nutlin, increased nuclear localization of p53 (4.05%-80.56%) was observed in pterygium cells along with increasing Nutlin dosages (from 0 to 50 μM, p < 0.001). The expression of p21 was increased after Nutlin treatments in pterygium cells (2.49 folds in 20 μM Nutlin treated cells compared to control treated cells, p = 0.012).
We discovered a novel mechanism in pterygium whereby MDM2 suppresses p53 transcriptional activity despite abundant p53 in pterygium. Disruption of MDM2-p53 interaction by Nutlin could be a potential treatment for pterygium.
确认鼠双微基因 2（MDM2）可抑制人翼状胬肉中的 p53 活性。并表明 MDM2-p53 相互作用的破坏可使 p53 在翼状胬肉中的功能恢复活性。
收集翼状胬肉和相应的结膜组织，建立原代细胞系。通过免疫荧光检测 MDM2 和 p53 的表达模式。定量测定未经处理和 MDM2 拮抗剂（Nutlin）处理的翼状胬肉细胞中 p53 和 MDM2 的蛋白定位以及 p53 的转录活性。
在翼状胬肉中，p53 在细胞质中高度表达，在核内略有表达。MDM2 定位于核内。p53 转录调控靶基因 p21 在翼状胬肉组织中不表达，表明 p53 转录活性在翼状胬肉中不活跃。在用 Nutlin 处理后，随着 Nutlin 剂量的增加（从 0 至 50 μM，p < 0.001），翼状胬肉细胞中 p53 的核内定位增加（4.05％-80.56％）。Nutlin 处理后翼状胬肉细胞中 p21 的表达增加（与对照处理细胞相比，20 μM Nutlin 处理细胞中增加了 2.49 倍，p = 0.012）。
我们在翼状胬肉中发现了一种新的机制，即尽管 p53 在翼状胬肉中含量丰富，但 MDM2 仍抑制 p53 的转录活性。Nutlin 破坏 MDM2-p53 相互作用可能是治疗翼状胬肉的一种潜在方法。
