Kwak Eunice L, Moberg Kenneth H, Wahrer Doke C R, Quinn Jennifer E, Gilmore Paula M, Graham Colin A, Hariharan Iswar K, Harkin D Paul, Haber Daniel A, Bell Daphne W
Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149, CNY-7, 13th Street, Charlestown, MA 02129, USA.
Gynecol Oncol. 2005 Jul;98(1):124-8. doi: 10.1016/j.ygyno.2005.04.007.
Archipelago (AGO, also known as hCdc4, Fbw7, or Sel-10) is an F-box containing component of the SCF complex implicated in the ubiquitination and proteolysis of cyclin E and c-Myc, and found to be mutated in 16% of endometrial carcinomas. We have previously reported somatic mutations in AGO in 3/10 ovarian cancer cell lines, but the frequency of such mutations in primary ovarian cancer is unknown.
The coding sequence of AGO was analyzed in 95 primary sporadic ovarian tumors and 16 cases of familial ovarian cancer, and correlated with levels of cyclin E and c-Myc protein expression. Constructs encoding mutations in AGO were transfected into an AGO-null cell line to directly test their ability to regulate cyclin E and c-Myc levels.
Mutations were present in only 2 of 95 sporadic cases: a premature stop within the WD domain (471 Ter) and a missense change near the F-box (S245T). Both primary tumor specimens containing these mutations showed high levels of cyclin E and c-Myc, but reconstitution of an AGO-null cell line with constructs encoding these mutations showed 471 Ter to be inactive in regulating endogenous cyclin E and c-Myc levels, while the S245T mutant was indistinguishable from wild-type. No germ-line mutations were found in familial cases of ovarian cancer.
Somatic AGO mutations are infrequent in primary ovarian cancers and are unlikely to contribute to familial ovarian cancer. Reconstitution experiments, rather than measuring tumor levels of cyclin E and c-Myc, provide an effective approach to determine the functional significance of AGO mutations identified in human cancers.
群岛蛋白（AGO，也称为hCdc4、Fbw7或Sel-10）是SCF复合物中含F-盒的组分，参与细胞周期蛋白E和c-Myc的泛素化及蛋白水解过程，在16%的子宫内膜癌中发现有该蛋白突变。我们之前报道在3/10的卵巢癌细胞系中存在AGO的体细胞突变，但原发性卵巢癌中此类突变的频率尚不清楚。
分析了95例原发性散发性卵巢肿瘤和16例家族性卵巢癌中AGO的编码序列，并与细胞周期蛋白E和c-Myc蛋白表达水平相关联。将编码AGO突变的构建体转染至AGO缺失的细胞系中，以直接测试其调节细胞周期蛋白E和c-Myc水平的能力。
95例散发性病例中仅2例存在突变：WD结构域内的一个提前终止突变（471Ter）和F-盒附近的一个错义突变（S245T）。含有这些突变的两个原发性肿瘤标本均显示细胞周期蛋白E和c-Myc水平较高，但用编码这些突变的构建体重构AGO缺失的细胞系后发现，471Ter在调节内源性细胞周期蛋白E和c-Myc水平方面无活性，而S245T突变体与野生型无差异。在家族性卵巢癌病例中未发现种系突变。
原发性卵巢癌中AGO的体细胞突变很少见，不太可能导致家族性卵巢癌。重组实验而非测量肿瘤中细胞周期蛋白E和c-Myc的水平，为确定在人类癌症中鉴定出的AGO突变的功能意义提供了一种有效方法。
