Hashimoto Yosuke, Parsons Maddy, Adams Josephine C
Department of Cell Biology, Lerner Research Institute, The Cleveland Clinic, Cleveland, OH 44195, USA.
Mol Biol Cell. 2007 Nov;18(11):4591-602. doi: 10.1091/mbc.e07-02-0157. Epub 2007 Sep 12.
Recurrence of carcinomas due to cells that migrate away from the primary tumor is a major problem in cancer treatment. Immunohistochemical analyses of human carcinomas have consistently correlated up-regulation of the actin-bundling protein fascin with a clinically aggressive phenotype and poor prognosis. To understand the functional and mechanistic contributions of fascin, we undertook inducible short hairpin RNA (shRNA) knockdown of fascin in human colon carcinoma cells derived from an aggressive primary tumor. Fascin-depletion led to decreased numbers of filopodia and altered morphology of cell protrusions, decreased Rac-dependent migration on laminin, decreased turnover of focal adhesions, and, in vivo, decreased xenograft tumor development and metastasis. cDNA rescue of fascin shRNA-knockdown cells with wild-type green fluorescent protein-fascin or fascins mutated at the protein kinase C (PKC) phosphorylation site revealed that both the actin-bundling and active PKC-binding activities of fascin are required for the organization of filopodial protrusions, Rac-dependent migration, and tumor metastasis. Thus, fascin contributes to carcinoma migration and metastasis through dual pathways that impact on multiple subcellular structures needed for cell migration.
癌细胞从原发肿瘤迁移导致的癌症复发是癌症治疗中的一个主要问题。对人类癌症的免疫组织化学分析一直表明，肌动蛋白捆绑蛋白fascin的上调与临床侵袭性表型和不良预后相关。为了了解fascin的功能和机制作用，我们对源自侵袭性原发肿瘤的人结肠癌细胞进行了诱导型短发夹RNA（shRNA）介导的fascin敲低。fascin缺失导致丝状伪足数量减少、细胞突起形态改变、在层粘连蛋白上Rac依赖性迁移减少、粘着斑周转减少，并且在体内，异种移植肿瘤的生长和转移减少。用野生型绿色荧光蛋白-fascin或在蛋白激酶C（PKC）磷酸化位点突变的fascin对fascin shRNA敲低细胞进行cDNA拯救，结果显示fascin的肌动蛋白捆绑活性和与活性PKC结合的活性对于丝状伪足突起的组织、Rac依赖性迁移和肿瘤转移都是必需的。因此，fascin通过影响细胞迁移所需的多个亚细胞结构的双重途径促进癌症迁移和转移。
