Department of Odontology, Umeå University, Umeå, Sweden.
J Eur Acad Dermatol Venereol. 2012 Nov;26(11):1415-9. doi: 10.1111/j.1468-3083.2011.04306.x. Epub 2011 Oct 24.
Oral lichen planus (OLP) is a chronic inflammatory disease for which the pathogenesis is not fully understood. OLP has autoimmune features and auto immunity has been suggested as a potential cause, whereas WHO has classified OLP as a premalignant condition. Association between chronic inflammation and cancer is known and chronic inflammation is one of the characteristics of OLP. A protein connected to inflammation and suggested to be involved in cancer development is cyclooxygenase-2 (COX-2) which can be inhibited by microRNA-26b (miR-26b).
The aim was to map levels of COX-2 and miR-26b in OLP lesions to see if there was any correlation between expression of COX-2 and its regulator miR-26b in OLP.
In biopsies from 20 OLP patients and 20 age and gender-matched controls laser- micro dissection of epithelium was performed. Quantitative RT-PCR, immunohistochemistry and Western blot were used in the analysis.
Levels of COX-2 mRNA were significantly higher while levels of miR-26b were significantly lower in OLP lesions compared to controls. Using immunohistochemistry normal oral mucosa samples did not show any expression of COX-2 while OLP samples expressed the protein. No COX-2 protein was detectable with Western blot.
Increased expression of COX-2 and decreased expression of miR-26b in OLP suggests both to play a role in OLP. COX-2 has been connected to both malignant development and autoimmunity but as malignant development of OLP is quite rare we suggest that the increased levels of COX-2 seen here support an autoimmune cause of the disease.
口腔扁平苔藓（OLP）是一种慢性炎症性疾病，其发病机制尚未完全阐明。OLP 具有自身免疫特征，自身免疫被认为是其潜在病因，而世界卫生组织（WHO）将 OLP 归类为癌前病变。慢性炎症与癌症之间存在关联，慢性炎症是 OLP 的特征之一。一种与炎症相关并被认为与癌症发展有关的蛋白是环氧化酶-2（COX-2），它可以被 microRNA-26b（miR-26b）抑制。
本研究旨在检测 OLP 病变中 COX-2 和 miR-26b 的水平，以观察 COX-2 及其调控因子 miR-26b 在 OLP 中的表达是否存在相关性。
对 20 例 OLP 患者和 20 例年龄和性别匹配的对照者的活检组织进行激光微切割，采用定量 RT-PCR、免疫组织化学和 Western blot 进行分析。
与对照组相比，OLP 病变中 COX-2 mRNA 水平显著升高，而 miR-26b 水平显著降低。免疫组织化学显示，正常口腔黏膜样本中无 COX-2 表达，而 OLP 样本中表达该蛋白。Western blot 未检测到 COX-2 蛋白。
OLP 中 COX-2 表达增加和 miR-26b 表达降低提示两者均在 OLP 中发挥作用。COX-2 与恶性发展和自身免疫均有关，但由于 OLP 的恶性发展相当罕见，我们认为此处观察到的 COX-2 水平升高支持该疾病的自身免疫病因。
