Pharmazentrum Frankfurt/ZAFES, University Hospital Goethe University Frankfurt, Frankfurt am Main, Germany.
PLoS One. 2011;6(8):e22312. doi: 10.1371/journal.pone.0022312. Epub 2011 Aug 18.
PAX transcription factors play an important role during development and carcinogenesis. In this study, we investigated PAX2 protein levels in melanocytes and melanoma cells by Western Blot and immunofluorescence analysis and characterized the role of PAX2 in the pathogenesis of melanoma. In vitro we found weak PAX2 protein expression in keratinocytes and melanocytes. Compared to melanocytes increased PAX2 protein levels were detectable in melanoma cell lines. Interestingly, in tissue sections of melanoma patients nuclear PAX2 expression strongly correlated with nuclear atypia and the degree of prominent nucleoli, indicating an association of PAX2 with a more atypical cellular phenotype. In addition, with chromatin immunoprecipitation assay, PAX2 overexpression and PAX2 siRNA we present compelling evidence that PAX2 can regulate ADAM10 expression, a metalloproteinase known to play important roles in melanoma metastasis. In human tissue samples we found co-expression of PAX2 and ADAM10 in melanocytes of benign nevi and in melanoma cells of patients with malignant melanoma. Importantly, the downregulation of PAX2 by specific siRNA inhibited the anchorage independent cell growth and decreased the migratory and invasive capacity of melanoma cells. Furthermore, the downregulation of PAX2 abrogated the chemoresistance of melanoma cells against cisplatin, indicating that PAX2 expression mediates cell survival and plays important roles during melanoma progression.
PAX 转录因子在发育和致癌过程中发挥着重要作用。在这项研究中，我们通过 Western Blot 和免疫荧光分析研究了 PAX2 蛋白在黑素细胞和黑色素瘤细胞中的水平，并探讨了 PAX2 在黑色素瘤发病机制中的作用。在体外，我们发现角质形成细胞和黑素细胞中 PAX2 蛋白表达较弱。与黑素细胞相比，在黑色素瘤细胞系中可检测到 PAX2 蛋白水平增加。有趣的是，在黑色素瘤患者的组织切片中，核 PAX2 表达与核异型性和突出核仁的程度强烈相关，表明 PAX2 与更典型的细胞表型相关。此外，通过染色质免疫沉淀测定、PAX2 过表达和 PAX2 siRNA，我们提供了令人信服的证据，表明 PAX2 可以调节 ADAM10 的表达，ADAM10 是一种已知在黑色素瘤转移中发挥重要作用的金属蛋白酶。在人类组织样本中，我们发现 PAX2 和 ADAM10 在良性痣的黑素细胞中和恶性黑色素瘤患者的黑色素瘤细胞中共同表达。重要的是，特异性 siRNA 下调 PAX2 抑制了黑色素瘤细胞的无锚定依赖性细胞生长，并降低了其迁移和侵袭能力。此外，PAX2 的下调消除了黑色素瘤细胞对顺铂的化疗耐药性，表明 PAX2 表达介导细胞存活，并在黑色素瘤进展过程中发挥重要作用。
