Hoek Keith S, Schlegel Natalie C, Eichhoff Ossia M, Widmer Daniel S, Praetorius Christian, Einarsson Steingrimur O, Valgeirsdottir Sigridur, Bergsteinsdottir Kristin, Schepsky Alexander, Dummer Reinhard, Steingrimsson Eirikur
Department of Dermatology, University Hospital of Zürich, Zürich, Switzerland.
Pigment Cell Melanoma Res. 2008 Dec;21(6):665-76. doi: 10.1111/j.1755-148X.2008.00505.x.
Malignant melanoma is a chemotherapy-resistant cancer with high mortality. Recent advances in our understanding of the disease at the molecular level have indicated that it shares many characteristics with developmental precursors to melanocytes, the mature pigment-producing cells of the skin and hair follicles. The development of melanocytes absolutely depends on the action of the microphthalmia-associated transcription factor (MITF). MITF has been shown to regulate a broad variety of genes, whose functions range from pigment production to cell-cycle regulation, migration and survival. However, the existing list of targets is not sufficient to explain the role of MITF in melanocyte development and melanoma progression. DNA microarray analysis of gene expression offers a straightforward approach to identify new target genes, but standard analytical procedures are susceptible to the generation of false positives and require additional experimental steps for validation. Here, we introduce a new strategy where two DNA microarray-based approaches for identifying transcription factor targets are combined in a cross-validation protocol designed to help control false-positive generation. We use this two-step approach to successfully re-identify thirteen previously recorded targets of MITF-mediated upregulation, as well as 71 novel targets. Many of these new targets have known relevance to pigmentation and melanoma biology, and further emphasize the critical role of MITF in these processes.
恶性黑色素瘤是一种对化疗耐药且死亡率高的癌症。我们在分子水平上对该疾病认识的最新进展表明，它与黑素细胞（皮肤和毛囊中产生色素的成熟细胞）的发育前体具有许多共同特征。黑素细胞的发育绝对依赖于小眼相关转录因子（MITF）的作用。已证明MITF可调节多种基因，其功能范围从色素生成到细胞周期调控、迁移和存活。然而，现有的靶标列表不足以解释MITF在黑素细胞发育和黑色素瘤进展中的作用。基因表达的DNA微阵列分析提供了一种直接的方法来鉴定新的靶基因，但标准分析程序容易产生假阳性，并且需要额外的实验步骤进行验证。在这里，我们引入了一种新策略，将两种基于DNA微阵列的转录因子靶标鉴定方法结合在一个旨在帮助控制假阳性产生的交叉验证方案中。我们使用这种两步法成功地重新鉴定了13个先前记录的MITF介导上调的靶标，以及71个新靶标。这些新靶标中的许多与色素沉着和黑色素瘤生物学已知相关，并进一步强调了MITF在这些过程中的关键作用。
