title: Pim-1 activation of cell motility induces the malignant phenotype of tongue carcinoma.
abstract: Pim-1 is a serine/threonine kinase as well as a proto-oncogene that induces T-cell lymphoma. Pim-1 induces cell cycle progression in cooperation with c-Myc and acts as an inhibitor of apoptotic cell death, actions that are involved in blood cell oncogenesis. However, little is known regarding the role of Pim-1 in oral carcinogenesis. We investigated Pim-1 expression in tongue squamous cell carcinoma (SCC) and examined its clinicopathological features. Western blotting was performed in 6 oral SCC cell lines, with Pim-1 being detected in all 6 of the lines. Immunohistochemical detection of Pim-1 was carried out in 39 cases of tongue SCC and analyzed in terms of its associated clinicopathological features. Pim-1 was expressed in 17/39 cases of tongue carcinoma, and was significantly correlated with lymph node metastasis. The role of Pim-1 in cell motility was further examined in HSC3 cells using the GTP-binding assay for Rho family protein, the motility assay and siRNA treatment. Rac1 activation was observed, and cell motility was reduced when Pim-1 was knocked down by siRNA. These results indicate that Pim-1 is involved in the carcinogenesis of oral SCC and is correlated to metastasis, which is in part associated with the enhancement of cell motility.
authors.affiliation: Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan.
authors.forename: Souichi
authors.initials: S
authors.lastname: Tanaka
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kitamura
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Higashino
authors.forename: Kyoko
authors.initials: K
authors.lastname: Hida
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ohiro
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Ono
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Totsuka
authors.forename: Masanobu
authors.initials: M
authors.lastname: Shindoh