Keratin down-regulation in vimentin-positive cancer cells is reversible by vimentin RNA interference, which inhibits growth and motility

Abstract

At later stages of tumor progression, epithelial carcinogenesis is associated with transition to a mesenchymal phenotype, which may contribute to the more aggressive properties of cancer cells and may be stimulated by growth factors such as epidermal growth factor and transforming growth factor-B. Previously, we found that cells derived from a nodal metastatic squamous cell carcinoma are highly proliferative and motile in vitro and tumorigenic in vivo. In the current study, we have investigated the role of vimentin in proliferation and motility. Cells derived from nodal metastasis express high levels of vimentin, which is undetectable in tumor cells derived from a synchronous primary lesion of tongue. Vimentin expression was enhanced by epidermal growth factor and transforming growth factor-B both independently and in combination. Use of RNA interference resulted in the generation of stable cell lines that express constitutively low levels of vimentin. RNA interference-mediated vimentin knockdown reduced cellular proliferation, migration, and invasion through a basement membrane substitute by 3-fold compared with nontargeting controls. In addition, cells with reduced vimentin reexpressed differentiation-specific keratins K13, K14, and K15 as a result of increased gene transcription as judged by quantitative PCR and promoterreporter assays. Furthermore, cells in which vimentin expression was reduced showed a greatly decreased tumorigenic potential, as tumors developing from these cells were 70% smaller than those from control cells. The data suggest that reversal of the mesenchymal phenotype by inhibiting vimentin expression results in reexpression of epithelial characteristics and reduced tumor aggressiveness. [Mol Cancer Ther 2008;7(9):2894 -903]

Keratin 8 and 18 Loss in Epithelial Cancer Cells Increases Collective Cell Migration and Cisplatin Sensitivity through Claudin1 Up-regulation

“…For example, forced expression of keratin 18 in a metastatic breast cancer cell line reduced the vimentin expression level, invasiveness in vitro, and metastatic spread in mice (18). In a similar way, stable silencing of vimentin in squamous carcinoma cells resulted in re-emergence of keratins and a concomitant reduction in cell invasiveness and tumorigenic potential (57). Conversely, suppression of both K8/18 in non-small cell lung cancer cell lines increased their invasiveness (58).…”

Upregulation of vimentin and aberrant expression of E-cadherin/β-catenin complex in oral squamous cell carcinomas: correlation with the clinicopathological features and patient outcome

“…Studies of human epithelial carcinomas, such as breast cancer, hepatocellular carcinoma, colon carcinoma, and prostatic adenocarcinoma, have shown that vimentin expression can be correlated with tumour invasion and a poor prognosis. [8][9][10][11][27][28][29][30][31][32] Several previous publications have detected the expression of vimentin in oral squamous cell carcinoma patients or cell lines. 8,40,50 To our knowledge, this is the first study to show that the overexpression of vimentin in oral squamous cell carcinoma specimens was closely associated with local recurrence.…”

“…27 Numerous data have shown that vimentin can be expressed in migratory epithelial cells that are involved in embryogenesis and organogenesis, wound healing, or tumour invasion. [28][29][30][31] Gilles et al 29 have shown that the vimentin promoter is a target of the b-catenin/TCF pathway, which suggests that this functional regulation of epithelial cells is involved in invasion and/or migration. 32 Currently, it is thought that the invasive front of tumours is the region containing the most useful prognostic information because, presumably, the most invasive cells are located there.…”

Association between periostin and epithelial-mesenchymal transition in esophageal squamous cell carcinoma and its clinical significance

“…Vim is a component of the cytoskeleton, is involved in cell adhesion and migration, and also regulates apoptosis and signal transduction in tumor tissues (6)(7)(8). EMT, as a target involved in invasion and metastasis mechanisms, has been revealed to result in the poor prognosis of patients with triple negative breast cancer and pancreatic cancer (9,10). EMT may be directly or indirectly mediated by various factors including snail, slug and twist.…”