Dataset Information

The mitogen-activated protein kinase kinase 4 has a pro-oncogenic role in skin cancer.

ABSTRACT: The mitogen-activated protein kinase (MAPK) kinase 4 (MKK4) is a nonredundant component of stress-activated MAPK signaling modules. Its function in tumorigenesis remains highly controversial with some studies indicating that MKK4 is a tumor suppressor, whereas others have reported a pro-oncogenic role. To clarify the role of MKK4 in cancer, we have created a novel mouse model to test the effect of the specific loss of MKK4 in the epidermis on the formation of papillomas caused by activated ras mutation. We have discovered that skin-specific MKK4-deficient mice are resistant to carcinogen-induced tumorigenesis. One mechanism by which MKK4 promotes cell proliferation and the formation of tumors is by increasing epidermal growth factor receptor expression through the c-Jun NH(2)-terminal protein kinase/c-Jun signaling pathway. Together, our results provide the first genetic demonstration that MKK4 is essential to mediate the oncogenic effect of Ras in vivo, thereby validating MKK4 as a potential drug target for cancer therapy.

SUBMITTER: Finegan KG

PROVIDER: S-EPMC2906708 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The mitogen-activated protein kinase kinase 4 has a pro-oncogenic role in skin cancer.

Finegan Katherine G KG Tournier Cathy C

Cancer research 20100707 14

The mitogen-activated protein kinase (MAPK) kinase 4 (MKK4) is a nonredundant component of stress-activated MAPK signaling modules. Its function in tumorigenesis remains highly controversial with some studies indicating that MKK4 is a tumor suppressor, whereas others have reported a pro-oncogenic role. To clarify the role of MKK4 in cancer, we have created a novel mouse model to test the effect of the specific loss of MKK4 in the epidermis on the formation of papillomas caused by activated ras m ...[more]

PMID: 20610622

Similar Datasets

Project description:Ras recruits and activates effectors that transmit receptor-initiated signals. Monomeric Ras can bind Raf; however, Raf's activation requires dimerization, which can be facilitated by Ras dimerization. Previously, we showed that active K-Ras4B dimerizes in silico and in vitro through two major interfaces: (i) β-interface, mapped to Switch I and effector-binding regions, (ii) α-interface at the allosteric lobe. Here, we chose constitutively active K-Ras4B as our control and two double mutants (K101D and R102E; and R41E and K42D) in the α- and β-interfaces. Two of the mutations are from The Cancer Genome Atlas (TCGA) and the Catalogue Of Somatic Mutations In Cancer (COSMIC) data sets. R41 and R102 are found in several adenocarcinomas in Ras isoforms. We performed site-directed mutagenesis, cellular localization experiments, and molecular dynamics (MD) simulations to assess the impact of the mutations on K-Ras4B dimerization and function. α-interface K101D/R102E double mutations reduced dimerization but only slightly reduced downstream phosphorylated extracellular signal-regulated kinase (ERK) (pERK) levels. While β-interface R41E/K42D double mutations did not interfere with dimerization, they almost completely blocked K-Ras4B-mediated ERK phosphorylation. Both double mutations increased downstream phosphorylated Akt (pAkt) levels in cells. Changes in pERK and pAkt levels altered ERK- and Akt-regulated gene expressions, such as EGR1, JUN, and BCL2L11. These results underscore the role of the α-interface in K-Ras4B homodimerization and the β-surface in effector binding. MD simulations highlight that the membrane and hypervariable region (HVR) interact with both α- and β-interfaces of K-Ras4B mutants, respectively, inhibiting homodimerization and probably effector binding. Mutations at both interfaces interfered with mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase signaling but in different forms and extents. We conclude that dimerization is not necessary but enhances downstream MAPK signaling.

Project description:BackgroundThe mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway plays an important role in papillary and anaplastic thyroid cancer (PTC and ATC) due to activating mutations in BRAF, RAS, or rearrangements in RET/PTC1. The objective of this study was to thoroughly test whether the BRAF V600E mutation predicts response to mitogen-activated protein kinase kinase 1/2 (MKK1/2) inhibition, as shown in other tumor types, using an authenticated panel of thyroid cancer cell lines.MethodsPTC and ATC cells harboring distinct mutations in the MAPK pathway were treated with two different inhibitors selective for MKK1/2 (CI-1040 or U0126). The consequences of MKK1/2 inhibition on cell growth, survival, invasion, and MAPK signaling was determined.ResultsInhibition of MKK1/2 using CI-1040 or U0126 differentially inhibits the growth of a panel of PTC and ATC cell lines in two-dimensional culture, with those harboring the BRAF V600E mutation (SW1736) or BRAF-V600E/PI3K-E542K mutations (K1) being the most sensitive, the RET/PTC1 rearrangement (TPC1) and BRAF V600E mutant (BCPAP), intermediate, and the HRAS-G13R mutant (C643), the least sensitive. Growth of these cells is more sensitive to MKK1/2 inhibition when grown in 2% versus 10% serum. Baseline levels of phospho-ERK1/2 were similar in all of the cell lines, and inhibition phospho-ERK1/2 did not predict sensitivity to MKK1/2 inhibition. When cells are grown in three-dimensional culture, MKK1/2 inhibition of growth correlates with mutational status (BRAF > RET/PTC1 > RAS). Finally, PTC and ATC invasiveness is differentially inhibited by CI-1040, which is independent of tumor type or mutation present.ConclusionsDifferent mutations in the MAPK pathway play distinct roles in the growth and invasion of thyroid cancer cells. These results indicate that MKK1/2 inhibitors have the potential to inhibit thyroid cancer growth and invasion, but that responses differ based on mutation status and growth conditions.

Dataset Information

The mitogen-activated protein kinase kinase 4 has a pro-oncogenic role in skin cancer.

Publications

The mitogen-activated protein kinase kinase 4 has a pro-oncogenic role in skin cancer.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets