title: Long-term exposure of human renal carcinoma cells to PD98059 induces epithelial-mesenchymal transition-like phenotype and enhanced motility.
abstract: Extracellular signal-regulated kinases (ERK) have fundamental roles in tumor progression. However, human clinical trials have shown little or no effect of inhibitors of their upstream signaling molecule, mitogen-activated protein kinase/ERK kinase (MEK), in advanced cancers. To determine the molecular mechanism underlying the limited antitumor effect, we cultured two human renal carcinoma cell lines, ACHN cells and VMRC-RCW cells in the presence of a MEK inhibitor PD98059 for more than 4 weeks (PD98059-exposed cells). PD98059-exposed ACHN cells showed elongated cell shape with scattering morphology, increase in vimentin expression, loss of beta-catenin junctional localization, stress fiber formation, and increased motility. In contrast, VMRC-RCW cells showed scattered phenotype without PD98059-treatment, and this treatment failed to increase the expression of vimentin. Rho A activity was increased in PD98059-exposed ACHN cells. In these cells, enhanced stress fiber formation and motility were observed, both of which were inhibited by treatment with small interfering RNA for Rho A or an Rho kinase inhibitor Y27632. Our results suggest that long-term exposure of human renal carcinoma cells to PD98059 increases cell motility by upregulating Rho A-Rho kinase signaling.
authors.affiliation: Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Science, 1-7-1, Sakamoto, Nagasaki, Japan. skanda-jua@umin.net
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kanda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kanetake
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Miyata
mesh_terms: D000577:Amides / Q000494:pharmacology; D002292:Carcinoma, Renal Cell / Q000201:enzymology / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D004848:Epithelium / Q000187:drug effects / Q000473:pathology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D008648:Mesoderm / Q000187:drug effects / Q000473:pathology*; D010641:Phenotype; D011725:Pyridines / Q000494:pharmacology; D022502:Stress Fibers / Q000187:drug effects / Q000473:pathology; D013997:Time Factors; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D000577:Amides; D005419:Flavonoids; D011725:Pyridines; C108830:Y 27632; D048049:Extracellular Signal-Regulated MAP Kinases; D020742:rhoA GTP-Binding Protein; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one