Inactivation of RASSF1C during in vivo tumor growth identifies it as a tumor suppressor gene
Inactivation of RASSF1C during in vivo tumor growth identifies it as a tumor suppressor gene
复制标题
DOI：
10.1038/sj.onc.1207789
复制
发表时间：
2004-08-05
期刊：
影响因子：
8
通讯作者：
Zabarovsky, E
中科院分区：
文献类型：
--
作者：
Li, JF;Wang, FL;Zabarovsky, E
RASSF1A 是 RASSF1 基因家族的主要成员，在大量人类实体瘤中被启动子甲基化高频率地沉默。 RASSF1A 的受控表达可恢复几种人类癌细胞系的致瘤表型。在这里，我们研究了另一种主要亚型 RASSF1C，并在基于四环素调控系统的基因失活测试 (GIT) 中将其与 RASSF1A 进行了比较。在小细胞肺癌 (SCLC) 系 U2020 中，只有 RASSF1A 显示出体外生长抑制活性，而在前列腺细胞系 LNCaP 和肾细胞癌 (RCC) 系 KRC/Y 中，RASSF1A 和 RASSF1C 均显示出相似的 (约 90%) 体外抑制活性。 RASSF1C 和 RASSF1A 均抑制 SCID 小鼠中 KRC/Y RCC 细胞系的致瘤性。在所有 15 个生长的 SCID 肿瘤中均发现了 RASSF1A 和 RASSF1C 转基因的突变、缺失和表达缺失。相比之下，含有Cys65Arg和Val211Ala的突变体RASSF1A在体外和体内均降低了生长抑制活性，并且在四个生长的SCID肿瘤中没有显示出任何进一步的变化。此外，RASSF1C 显示可诱导 KRC/Y 细胞的细胞周期停滞。这些结果强烈表明，与 RASSF1A 一样，RASSF1C 基因也可以发挥肿瘤抑制功能。
RASSF1A, a major member of the RASSF1 gene family, is silenced by promoter methylation at a high frequency in a large number of human solid tumors. Controlled expression of RASSF1A reverts the tumorigenic phenotype of several human cancer cell lines. Here we investigated another main isoform, RASSF1C, and compared it with RASSF1A in the gene inactivation test (GIT), based on a tetracycline regulation system. In the small-cell lung cancer (SCLC) line U2020, only RASSF1A has shown growth inhibitory activity in vitro, while in the prostate cell line LNCaP and renal cell carcinoma (RCC) line KRC/Y both RASSF1A and RASSF1C showed similar (approximately 90%) suppressing activity in vitro. Both RASSF1C and RASSF1A suppressed the tumorigenicity of the KRC/Y RCC cell line in SCID mice. Mutations, deletions and loss of expression of RASSF1A and RASSF1C transgenes were identified in all 15 grown SCID tumors. In contrast, the mutant RASSF1A containing Cys65Arg and Val211Ala had reduced growth suppression activity both in vitro and in vivo and did not show any further changes in four grown SCID tumors. In addition, RASSF1C was shown to induce cell cycle arrest in KRC/Y cells. These results strongly imply that like RASSF1A the RASSF1C gene could serve a tumor suppressor function.