MicroRNA在葡萄膜恶性黑色素瘤中的研究进展

恶性黑色素瘤恶性程度高,易经血流转移,是成年人中最多见的一种恶性眼内肿瘤,其发生发展涉及到多步骤的分子生物学机制,包括原癌基因和抑癌基因的遗传和表观遗传学改变。因此研究参与此过程的分子机制能为肿瘤的有效治疗提供有益的见解。微小核糖核酸（ｍｉｃｒｏＲＮＡ,ｍｉＲＮＡ）是一类长约２２个核苷酸的非编码单链小分子ＲＮＡ,在各种生理病理过程中发挥了重要作用,最新的研究发现,异常表达的ｍｉｃｒｏＲＮＡ参与了葡萄膜恶性黑色素瘤众多的病理过程。本文综述了ｍｉｃｒｏＲＮＡ的发现、形成及作用机制,葡萄膜恶性黑色素瘤中ｍｉｃｒｏＲＮＡ的异常表达及其可能机制,ｍｉｃｒｏＲＮＡ与葡萄膜恶性黑色素瘤的发生与增殖、侵袭和转移以及ｍｉｃｒｏＲＮＡ在葡萄膜恶性黑色素瘤中的临床应用价值。     

葡萄膜黑色素瘤染色体异常及检测方法

葡萄膜黑色素瘤是成年人最常见的眼内原发性恶性肿瘤,细胞遗传学的研究显示葡萄膜黑色素瘤细胞存在特征性的染色体异常,并与肿瘤的预后相关.这些特征性的染色体异常提示可能存在癌基因与抑癌基因,这有助于阐明肿瘤发生发展的机制.可用于检测葡萄膜黑色素瘤染色体异常的方法很多,随着科学技术的发展,检测手段也不断更新.本文对目前发现的葡...     

二代测序在葡萄膜黑色素瘤发病机制研究中的应用进展

葡萄膜黑色素瘤作为成人最常见的眼内恶性肿瘤, 转移后治疗效果不佳。近年来, 二代测序技术在研究疾病遗传特征上得到越来越多的应用。本文从基因组学, 表观基因组和转录组角度出发, 概括了二代测序技术应用下葡萄膜黑色素瘤致病相关的基因组变异, 表观基因组调控机制变化和转录组水平上肿瘤免疫特征, 尤其从染色体拷贝数变异、基因突变和DNA甲基化水平改变等方面进行阐述。     

DNA甲基化在晶状体发育及白内障中的研究进展

表观遗传学是指基因碱基序列在未发生改变的情况下调控基因表达的一门学科,其研究领域主要涉及DNA甲基化、组蛋白修饰和非编码RNA,其中DNA甲基化沉默基因的表达是表观遗传学重要的调控机制.DNA甲基化状态受环境因素的影响,而晶状体发育异常及白内障形成由多种致病因素决定,其中包括环境因素.因此,研究DNA甲基化在晶状体发育及白内障形成过程中的作用机制尤为重要.本文就近年来DNA甲基化在晶状体发育、年龄相关性白内障、并发性白内障、后发性白内障发病机制中的作用进行综述,通过对DNA甲基化在上述眼部疾病及晶状体发育过程中作用机制的认识及研究,有望在白内障临床治疗中开辟新的途径.     

表观遗传学在眼内肿瘤研究中的应用

表观遗传学（epigenetics）的研究对象是在未出现DNA序列改变的前提下发生的可遗传的基因功能变化。随着对肿瘤认识的深入,人们发现DNA序列以外的调控机制（即表观遗传学）异常在肿瘤的发生、发展过程中也起到非常重要的作用。本文将具体介绍表观遗传学在癌症发生中尤其是在眼内恶性肿瘤研究中的应用。     

白内障表观遗传学研究的现状及进展

白内障是全球最常见的致盲眼病,其发病机制仍不清楚。表观遗传学研究的出现阐述了白内障可能的发病机制,推动了白内障基础研究的进展,已成为生物医学研究的热点。目前表观遗传学调节主要包括DNA甲基化、组蛋白修饰和非编码RNA。近年来表观遗传学研究发现,白内障是由表观遗传学与基因改变共同引起,一些晶状体蛋白及氧化     

葡萄膜黑色素瘤染色体异常及其相关基因研究进展

葡萄膜黑色素瘤存在多种染色体异常及基因表达异常。3号染色体缺失和8号染色体获得与葡萄膜黑色素瘤的转移和预后密切相关，可作为其分型和预后评判的指标；6号染色体的异常与葡萄膜黑色素瘤不同表型的侵袭能力有关。Cyclin D1、MTS1、MDM2、Bcl-2等基因表达异常与葡萄膜黑色素瘤的发生有关，DDEF1、NBS1基因的表达与葡萄膜黑色素瘤的侵袭能力和转移密切相关。     

表观遗传学简介

最近几年,表观遗传学已经成为生物医学研究的热点。表观遗传学是指表观遗传学改变（DNA甲基化、组蛋白修饰和非编码RNAs如miRNAs）对表观基因组基因表达的调节,这种调节不依赖基因序列的改变且可遗传。表观遗传学因素如DNA甲基化、组蛋白修饰和miRNA是对环境刺激因素变化的反映,这些表观遗传学因素相互作用以调节基因表达,控制细胞表型,所有这些表观遗传学因素都是维持机体内环境稳定所必需的,有助于正常生理功能的发挥,但表观遗传学异常也是很多疾病发生的原因。除此之外,表观遗传学药物已经应用于临床试验特别是癌症的治疗。因此了解表观遗传学机制在人类疾病发生中的作用和表观遗传学调节剂对疾病治疗的价值将会迎来生物医学研究的表观遗传学时代。     

应重视表观遗传学与晶状体的相关研究

表观遗传学是传统遗传学的分支之一,目前已成为生物医学中一个日益重要的研究领域,是研究不涉及DNA序列改变,而通过DNA甲基化、组蛋白修饰、非编码RNA,如miRNA等方式对基因表型进行调控并可进行遗传的科学。目前已发现,表观遗传学与生命科学密切相关,在眼科学领域,表观遗传与各种眼组织的生理活动和疾病发生均有关联。由于传统遗传学导致的疾病不可逆,而表观遗传是可逆的过程,因此表观遗传与眼科疾病关系的研究正逐渐引起重视。晶状体上皮细胞（LECs）的生长、分化、衰老、上皮一间充质转化（EMT）等均受到表观遗传学的调控,晶状体疾病,如白内障可能与表观遗传学因素有密切关联,大力开展晶状体表观遗传学研究可能为研究白内障的发病机制及防治提供新的思路和方法。目前国内外一些研究者已将表观遗传学方法应用于晶状体生理和病理的研究,国内的眼科医学工作者应关注和跟踪这些新的研究动态和前沿,并积极参与其中。     

拷贝数变异及其在眼病分子遗传学研究中的应用

拷贝数变异(CNV)是人类基因组内大于1kb的DNA片段拷贝数的异常变化,它广泛存在于正常个体,可能是人类表型变异的重要原因之一,是研究包括眼病在内的人类疾病的热点.目前认为CNV的形成机制可能是非等位基因同源性重组和非同源末端连接等所致.本文对CNV的多态性与表型变异、形成机制、检测方法及其在青光眼、白内障、虹膜发育不良、葡萄膜黑色素瘤、X-连锁眼白化病等眼病分子遗传学中的应用进行综述.     

Angiogenic profile of uveal melanoma

Uveal melanoma develops in one of the most capillary-rich tissues of the body and is disseminated hematogenously. Knowledge of the nature and the spatiotemporal expression of angiogenic factors in uveal melanoma is essential to the development of new treatment strategies, especially with regard to improving survival. In this study, we measured the angiogenic potential of several angiogenic factors in different uveal melanoma cell lines, in an in vivo model, and in primary tumor material from patients with melanoma. Most uveal melanoma cell lines expressed vascular endothelial growth factor (VEGF)-A (isoforms 121, 165, 189), VEGF-B, VEGF-C, VEGF-D, and basic fibroblastic growth factor (b-FGF) to various extents. The expression of VEGF-A 121 was always higher than that of the other VEGF-A isoforms, suggesting that VEGF-A 121 is the most abundant VEGF-A isoform. All experimentally induced tumors expressed VEGF-A, VEGF-B, VEGF-C, VEGF-D, and basic fibroblastic growth factor (b-FGF). Similarly, significant amounts of mRNA for VEGF-B, VEGF-C, VEGF-D, and b-FGF were detected in uveal melanoma material from patients. In contrast, VEGF-A mRNA (121, 165, 189) was low (9/28) or not detectable in the tumor samples. The synthesis of VEGF-A 165 and b-FGF protein by various cell lines was measured by enzyme-linked immunosorbent assay (ELISA). Most uveal melanoma cell lines, but not normal melanocytes, strongly synthesized and secreted VEGF-A 165 and b-FGF during cell culture. Our data suggest that the expression of (lymph) angiogenic factors may play a causal role in the angiogenesis and progression of uveal melanoma and distant metastasis.     

细胞周期相关基因在葡萄膜黑色素瘤中的 表达与意义

目的探讨细胞周期相关基因与葡萄膜黑色素瘤病理分型及浸润能力的关系。方法采用免疫组化法定量检测96例葡萄膜黑色素瘤 标本中cyclinD1和Bcl-2蛋白的表达。结果Bcl-2在所有葡萄膜黑色素瘤中均有较高表达,与病理学分型及巩膜外浸润无关;cyclinD1的表达依梭型 、混合型、上皮型逐渐增高,与肿瘤的浸润能力呈正相关。结论bcl-2的表达对于葡萄膜黑色素瘤细胞的存活具有重要作用,cyclinD1可作为其恶性程度的评估指标。(中华眼底病杂志,2001,17:44-46)     

Genomic Investigations of Posterior Uveal Melanoma

The specific genetic mechanisms responsible for the malignant behavior of uveal melanoma are not known. Unlike cutaneous melanoma, epidemiologic studies have not demonstrated a definitive germline form of uveal melanoma, though familial melanoma and racial predilections occur. Molecular cytogenetic characterization of uveal melanoma suggests that somatic deletions of chromosome 3 are associated with a worse prognosis. Microarray technology has been used to characterize uveal melanoma gene expression and may provide tests useful for determining prognosis. As an improved understanding of the cellular mechanisms used by uveal melanoma is gained, new opportunities to adapt or design therapeutic approaches may emerge.     

Genomic investigations of posterior uveal melanoma

The specific genetic mechanisms responsible for the malignant behavior of uveal melanoma are not known. Unlike cutaneous melanoma, epidemiologic studies have not demonstrated a definitive germline form of uveal melanoma, though familial melanoma and racial predilections occur. Molecular cytogenetic characterization of uveal melanoma suggests that somatic deletions of chromosome 3 are associated with a worse prognosis. Microarray technology has been used to characterize uveal melanoma gene expression and may provide tests useful for determining prognosis. As an improved understanding of the cellular mechanisms used by uveal melanoma is gained, new opportunities to adapt or design therapeutic approaches may emerge.     

Heat shock protein expression in the eye and in uveal melanoma

PURPOSE: Expression of heat shock proteins (HSPs) is of prognostic significance in several tumor types, whereas HSPs may also have clinical use as stimulators in tumor vaccination. HSP expression levels were determined in normal eyes and in uveal melanoma and tested whether HSPs expression was associated with prognostic parameters in the uveal melanoma. METHODS: Expression of HSP27, HSP70, HSP90, and glycoprotein96 (GP96) were determined on paraffin-embedded and frozen sections from seven healthy eyes, 20 primary uveal melanomas without prior treatment, and 18 uveal melanomas after prior treatment. HSP expression was determined by alkaline phosphatase-anti-alkaline phosphatase (APAAP) immunohistochemistry, using appropriate monoclonal antibodies and scored semiquantitatively. Expression of HSPs was validated on retinal tissue of a normal eye and in two uveal melanoma cell lines by Western blot analysis. RESULTS: Expression of HSPs was observed in epithelial and pigment cells of the normal eyes. In uveal melanoma, the level of expression of HSPs varied. Expression of HSP27 and GP96 was noted in more than 30 of 38 uveal melanomas (with, respectively, a mean of 66% and 53% positive cells). HSP70 and HSP90 were expressed in 6% of tumor cells. The amount of expression of any of the HSP types was not significantly associated with known prognostic factors. There was not a significant difference in expression of the HSPs between uveal melanomas with or without any type of prior treatment. CONCLUSIONS: In this study, expression of HSPs in uveal melanoma is not correlated with known histopathologic prognostic factors. The high expression of GP96 indicates that this protein is a potential vector in tumor vaccination in patients with large uveal melanomas.     

PD-L1: PD-1 interaction contributes to the functional suppression of T-cell responses to human uveal melanoma cells in vitro

PURPOSE: To assess the expression of PD-L1 on human uveal melanomas and its potential to suppress T-cell function. METHODS: A panel of primary and metastatic uveal melanoma cell lines was evaluated for PD-L1 expression by RT-PCR and flow cytometric analysis. Uveal melanoma-containing eyes were examined for PD-L1 expression by immunohistochemistry. PD-L1 function was tested by coculturing IFN-gamma-pretreated uveal melanoma cells with activated Jurkat T cells for 48 hours and assessing T-cell production of IL-2 by ELISA. RESULTS: Five of the nine primary and one of the five metastatic uveal melanoma cell lines tested constitutively expressed PD-L1 protein at various levels. However, all primary and metastatic uveal melanoma cell lines upregulated PD-L1 expression after stimulation with IFN-gamma. Immunohistochemistry demonstrated that PD-L1 was not expressed by primary uveal melanomas in situ. IL-2 production by activated Jurkat T cells was decreased significantly when the cells were cocultured with IFN-gamma-pretreated uveal melanoma cells. More than 70% of IL-2 production was restored by addition of either anti-PD-L1 or anti-PD-1 antibody to the coculture assays (P < 0.01). CONCLUSIONS: Expression of PD-L1 by uveal melanoma cells regulates T-cell function by suppressing IL-2 production. The results imply that the presence of IFN-gamma in the tumor local microenvironment promotes upregulation of PD-L1 expression by uveal melanoma, which may, in part, promote immune escape by impairing T-cell function. The selective blockade of PD-L1 is a potential strategy in T-cell-based immunotherapy for uveal melanoma.