Hendrix M J, Seftor E A, Seftor R E, Gardner L M, Boldt H C, Meyer M, Pe'er J, Folberg R
Department of Anatomy, Iowa Cancer Center, The University of Iowa College of Medicine, Iowa City 52242-1109, USA.
Lab Invest. 1998 Feb;78(2):153-63.
The long-range goal of our research is to develop intervention strategies based on newly discovered biologic mechanisms responsible for the invasive dissemination of metastatic uveal melanoma. To accomplish this goal, we have focused on the biologic relevance of novel marker proteins contributing to the uveal melanoma metastatic phenotype. The expression of vimentin intermediate filaments (IFs), a mesenchymal marker, is typical of melanomas, whereas carcinomas typically express keratin IFs, which are markers for epithelia. Thus, cells that coexpress both IFs are regarded as "interconverted" in that they display both mesenchymal and epithelial phenotypes. Although the biologic functions of IFs have remained enigmatic, there is substantial support to suggest that the significance of vimentin/keratin coexpression is linked with poor patient outcome in cutaneous melanoma. Our data demonstrate that human uveal melanoma cell lines (isolated from primary choroidal or ciliary body melanomas and from foci of metastatic uveal melanoma to the liver), which contain predominant populations of cells that coexpress vimentin/keratins 8 and 18 (keratins 8,18) IFs, were 6-fold more invasive through collagenous extracellular matrices in vitro, compared with uveal melanoma cells expressing vimentin only, and were 8- to 13-fold more invasive than normal uveal melanocytes. Colocalization of vimentin/keratins 8,18 in cell cultures was corroborated by immunohistochemistry in histologic sections of tumors from which the cell lines were derived. Minor populations of these cells also coexpressed keratins 13 and 17. Experimental down-regulation of the predominant keratins 8,18 in the interconverted cells, using 16-mer antisense oligonucleotides, resulted in a significant decrease in the migratory ability of the cells-similar to levels achieved by cells positive only for vimentin. These findings provide justification for additional studies of the association between coexpression of IFs vimentin/keratins 8,18 and uveal melanoma metastasis.
我们研究的长期目标是基于新发现的负责转移性葡萄膜黑色素瘤侵袭性播散的生物学机制，开发干预策略。为实现这一目标，我们聚焦于有助于葡萄膜黑色素瘤转移表型的新型标记蛋白的生物学相关性。波形蛋白中间丝（IFs）是一种间充质标记物，其表达是黑色素瘤的典型特征，而癌通常表达角蛋白IFs，角蛋白是上皮细胞的标记物。因此，同时表达这两种IFs的细胞被视为“相互转化”，因为它们同时表现出间充质和上皮表型。尽管IFs的生物学功能仍然不明，但有大量证据表明波形蛋白/角蛋白共表达的意义与皮肤黑色素瘤患者的不良预后相关。我们的数据表明，人葡萄膜黑色素瘤细胞系（从原发性脉络膜或睫状体黑色素瘤以及葡萄膜黑色素瘤肝转移灶分离而来），其中主要细胞群体同时表达波形蛋白/角蛋白8和18（角蛋白8、18）IFs，与仅表达波形蛋白的葡萄膜黑色素瘤细胞相比，在体外通过胶原细胞外基质的侵袭性高6倍，比正常葡萄膜黑色素细胞的侵袭性高8至13倍。波形蛋白/角蛋白8、18在细胞培养物中的共定位通过免疫组织化学在源自这些细胞系的肿瘤组织切片中得到证实。这些细胞的少数群体也共表达角蛋白13和17。使用16聚体反义寡核苷酸对相互转化细胞中主要的角蛋白8、18进行实验性下调，导致细胞迁移能力显著下降——与仅波形蛋白阳性的细胞所达到的水平相似。这些发现为进一步研究IFs波形蛋白/角蛋白8、18共表达与葡萄膜黑色素瘤转移之间的关联提供了依据。
