title: Inactivation of the mitogen-activated protein kinase pathway as a potential target-based therapy in ovarian serous tumors with KRAS or BRAF mutations.
abstract: Activation of mitogen-activated protein kinase (MAPK) occurs in response to various growth stimulating signals and as a result of activating mutations of the upstream regulators, KRAS and BRAF, which can be found in many types of human cancer. To investigate the roles of MAPK activation in tumors harboring KRAS or BRAF mutations, we inactivated MAPK in ovarian tumor cells using CI-1040, a compound that selectively inhibits MAPK kinase, an upstream regulator of MAPK and thus prevents MAPK activation. Profound growth inhibition and apoptosis were observed in CI-1040-treated tumor cells with mutations in either KRAS or BRAF in comparison with the ovarian cancer cells containing wild-type sequences. Long serial analysis of gene expression identified several differentially expressed genes in CI-1040-treated MPSC1 cells harboring an activating mutation in BRAF (V599L). The most striking changes were down-regulation of cyclin D1, COBRA1, and transglutaminase-2 and up-regulation of tumor necrosis factor-related apoptosis-induced ligand, thrombospondin-1, optineurin, and palladin. These patterns of gene expression were validated in other CI-1040-treated tumor cells based on quantitative PCR. Constitutive expression of cyclin D1 partially reversed the growth inhibitory effect of CI-1040 in MPSC1 cells. Our findings indicate that an activated MAPK pathway is critical in tumor growth and survival of ovarian tumors with KRAS or BRAF mutations and suggest that the CI-1040 induced phenotypes depend on the mutational status of KRAS and BRAF in ovarian tumors.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Pohl
authors.forename: Chung-Liang
authors.initials: CL
authors.lastname: Ho
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Kurman
authors.forename: Robert
authors.initials: R
authors.lastname: Bristow
authors.forename: Tian-Li
authors.initials: TL
authors.lastname: Wang
authors.forename: Ie-Ming
authors.initials: IeM
authors.lastname: Shih
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D019938:Cyclin D1 / Q000378:metabolism; D018284:Cystadenocarcinoma, Serous / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
chemical_list: C120227:2-(2-chloro-4-iodophenylamino)-N-cyclopropylmethoxy-3,4-difluorobenzamide; D001549:Benzamides; D019938:Cyclin D1; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases