Rosenberg Dan, Groussin Lionel, Jullian Eric, Perlemoine Karine, Medjane Samir, Louvel Albert, Bertagna Xavier, Bertherat Jérôme
Department of Endocrinology, Institut Cochin, Institut National de la Santé et de la Recherche Médicale U576, René Descartes-Paris V University, 75014 Paris, France.
J Clin Endocrinol Metab. 2003 Aug;88(8):3958-65. doi: 10.1210/jc.2003-030070.
Various cellular and molecular alterations of the cAMP pathway have been observed in adrenal Cushing syndrome. We recently reported the loss of cAMP-responsive element-binding protein (CREB) expression in the adrenocortical cancer cell line H295R. CREB is the major nuclear target of the cAMP pathway. This study therefore aimed to analyze the status of the CREB protein in various types of human adrenocortical tumors and normal fetal adrenal cortex. CREB protein status was studied by Western blotting in adrenocortical adenomas (AAs, n = 27) and adrenocortical carcinomas (ACs, n = 24). A decrease of CREB protein was noticed in the majority of the adrenocortical tumors. The dramatic decrease in CREB protein levels was more pronounced in ACs than in AAs. Levels of the phosphorylated form of CREB were also low in adrenocortical tumors, with a greater decrease in ACs than in AAs. EMSAs also showed decreases in the amounts of CREB- containing complexes in nuclear extracts from adrenocortical tumors. The secretory status of adenomas was strongly correlated with CREB levels, significantly lower in nonfunctioning AAs (n = 9) than in functioning AAs (n = 9). CREB levels, determined by Western blotting and immunohistochemistry, were very low in the fetal zone of human fetal adrenal cortex, whereas they were normal in the definitive zone. In tumors, adrenocortical cells in several zones were weakly immunohistochemically stained for CREB, whereas CREB was uniformly detected in nonendocrine cell nuclei (e.g. vascular cells, fibroblasts). These results suggest that the absence of CREB may be linked to the development of a highly aggressive tumor with a dedifferentiated benign (nonfunctioning AA) or malignant (AC) phenotype. These findings highlight the similarities between the normal human fetal adrenal gland and adrenal cancers previously observed in terms of parallelism in IGF-II production.
在肾上腺库欣综合征中已观察到环磷酸腺苷（cAMP）信号通路的各种细胞和分子改变。我们最近报道了肾上腺皮质癌细胞系H295R中环磷酸腺苷反应元件结合蛋白（CREB）表达缺失。CREB是cAMP信号通路的主要核靶点。因此，本研究旨在分析不同类型的人类肾上腺皮质肿瘤和正常胎儿肾上腺皮质中CREB蛋白的状态。通过蛋白质免疫印迹法研究了肾上腺皮质腺瘤（AAs，n = 27）和肾上腺皮质癌（ACs，n = 24）中CREB蛋白的状态。在大多数肾上腺皮质肿瘤中发现CREB蛋白减少。CREB蛋白水平的显著降低在ACs中比在AAs中更明显。肾上腺皮质肿瘤中CREB磷酸化形式的水平也较低，ACs中的降低程度大于AAs。电泳迁移率变动分析（EMSA）也显示肾上腺皮质肿瘤核提取物中含CREB复合物的量减少。腺瘤的分泌状态与CREB水平密切相关，无功能AAs（n = 9）中的CREB水平显著低于有功能AAs（n = 9）。通过蛋白质免疫印迹法和免疫组织化学测定，人胎儿肾上腺皮质胎儿带中的CREB水平非常低，而在永久带中则正常。在肿瘤中，几个区域的肾上腺皮质细胞CREB免疫组化染色较弱，而在非内分泌细胞核（如血管细胞、成纤维细胞）中可均匀检测到CREB。这些结果表明，CREB的缺失可能与具有去分化良性（无功能AA）或恶性（AC）表型的高度侵袭性肿瘤的发生有关。这些发现突出了正常人类胎儿肾上腺与先前观察到的肾上腺癌在胰岛素样生长因子-II（IGF-II）产生平行性方面的相似性。
