Identification of a Novel Inhibitor of Mitogen-activated Protein Kinase Kinase

Favata, Margaret; Horiuchi, Kazuo; Manos, Elizabeth J.; Daulerio, Andrea J.; Stradley, Deborah A.; Feeser, Wendi S.; Dyk, Drew E. Van; Pitts, William J.; Earl, Richard A.; Hobbs, Frank W.; Copeland, Robert A.; Magolda, Ronald L.; Scherle, Peggy; Trzaskos, James M.

doi:10.1074/jbc.273.29.18623

Cited by 2,844 publications

(2,198 citation statements)

References 38 publications

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“…U0126 at 50 mM is widely used to prevent Erk activation in vivo without toxic effects on cells (Ahn et al, 2001). In a panel of more than 29 kinases tested, U0126 has little effect on kinases (including those of the most closely related MKK3, MKK4, MKK6, and MKK7) other than MEK1 and MEK2 (Favata et al, 1998;Davies et al, 2000). We show here that these inhibitors also block the downstream events of ATR in response to HU.…”

Section: Discussionmentioning

confidence: 73%

“…U0126 and PD98059, which are MEK1 and MEK2 inhibitors, effectively block HU-induced ATR nuclear foci. Both inhibitors are well characterized and are among the most specific protein kinase inhibitors (Favata et al, 1998;Davies et al, 2000). U0126 at 50 mM is widely used to prevent Erk activation in vivo without toxic effects on cells (Ahn et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

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ERK activity facilitates activation of the S-phase DNA damage checkpoint by modulating ATR function

Chen

Parihar

et al. 2005

Oncogene

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Although Erk kinase has been recently reported to function in the DNA damage response, the mechanism governing this process is unknown. We report here that hydroxyurea (HU) activates Erk via MEK1, a process that is sensitized by a constitutively active MEK1 (MEK1Q56P) and attenuated by a dominant-negative MEK1 (MEK1K97M). While ectopic MEK1Q56P sensitized HU-induced S-phase arrest, inhibition of Erk activation via U0126, PD98059, and MEK1K97M attenuated the arrest, and thereby enhanced cells to HU-induced toxicity. Taken together, we demonstrate an important contribution of Erk to the activation of the S-phase DNA damage checkpoint. This can be attributed to Erk's regulatory role in modulating ATR function. Inhibition of Erk activation with U0126/PD98059 and MEK1K97M substantially reduced HU-induced ATR nuclear foci, leading to a dramatic reduction of cH2AX and its nuclear foci. Reduction of MEK1 function by a small interference RNA (siRNA) MEK1 and ectopic MEK1K97M significantly decreased HU-induced cH2AX. Conversely, ectopic MEK1Q56P enhanced cH2AX foci. Furthermore, immunofluorescent and cell fractioning experiments revealed cytosolic and nuclear localization of ATR. HU treatment caused the redistribution of ATR from the cytosol to the nucleus, a process that is inhibited by U0126. Collectively, we show that Erk kinase modulates HU-initiated DNA damage response by regulating ATR function.

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

ERK activity facilitates activation of the S-phase DNA damage checkpoint by modulating ATR function

Chen

Parihar

et al. 2005

Oncogene

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“…The MAPK pathway consists of three major members: c-Jun-NH 2 -terminal kinase (JNK), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38 [24]. Their specific inhibitors including: SP600125 (10 -5 M, inhibitor of JNK) [25], PD98059 and U0126 (10 -5 M, inhibitors of ERK1/2) [26,27] and SB203580 (10 -5 M, inhibitor of p38) [28] were employed to examine the involvement of different MAPK subtypes. Actinomycin D (AcD, 5 mg/L) and cycloheximide (CHX, 10 -5 M) were used as general transcriptional and translational inhibitors, respectively.…”

Section: Intracellular Signal Inhibitions and Drugsmentioning

confidence: 99%

Up-regulation of thromboxane A2 receptor expression by lipid soluble smoking particles through post-transcriptional mechanisms

Zhang

Edvinsson

et al. 2008

Atherosclerosis

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“…For these experiments, we used both PD98059 and another ERK pathway inhibitor, U0126 (Favata et al, 1998). In the representative experiment shown in Figure 8d, T47D cells were pretreated with vehicle (lanes 1 and 2) or U0126 (lanes 3 and 4) before stimulation with EGF for 15 min.…”

Section: Prl Alters Egf-induced Egfr Downregulation In An Erk-dependementioning

confidence: 99%

Prolactin modulates phosphorylation, signaling and trafficking of epidermal growth factor receptor in human T47D breast cancer cells

Huang

Jiang

et al. 2006

Oncogene

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Prolactin (PRL) is a polypeptide hormone produced by the anterior pituitary gland and other sites that acts both systemically and locally to cause lactation and other biological effects by interacting with the PRL receptor, a Janus kinase (JAK)2-coupled cytokine receptor family member, and activating downstream signal pathways. Recent evidence suggests PRL is a player in the pathogenesis and progression of breast cancer. Epidermal growth factor (EGF) also has effects on breast tissue, working through its receptors, epidermal growth factor receptor (EGFR) and ErbB-2 (c-neu, HER2), both intrinsic tyrosine kinase growth factor receptors. EGFR promotes pubertal breast ductal morphogenesis in mice, and both EGFR and ErbB-2 are relevant in pathogenesis and behavior of breast and other human cancers. Previous studies showed that PRL and EGF synergize to enhance motility in the human breast cancer cell line, T47D. In this study, we explored crosstalk between the PRL and EGF signaling pathways in T47D cells, with an ultimate aim of understanding how these two important factors might work together in vivo to affect breast cancer behavior. Both PRL and EGF caused robust signaling in T47D cells; PRL acutely activated JAK2, signal transducer and activator of transcription-5 (STAT5), and extracellular signal-regulated kinase-1 and -2 (ERK1 and ERK2), whereas EGF caused EGFR activation and consequent src homology collagen (SHC) activation and ERK activation. Notably, PRL also caused phosphorylation of the EGFR and ErbB-2 at sites detected by PTP101, an antibody that recognizes threonine phosphorylation at consensus motifs for ERK-induced phosphorylation. PRL-induced PTP101-reactive phosphorylation was prevented by pretreatment with PD98059, an ERK pathway inhibitor. Furthermore, PRL synergized with EGF in activating SHC and ERK and transactivating a luciferase reporter driven by c-fos gene enhancer elements, suggesting that PRL allowed markedly enhanced EGF signaling. This was accompanied by substantial inhibition of EGF-induced EGFR downregulation when PRL and EGF cotreatment was compared to EGF treatment alone. This effect of PRL was abrogated by ERK pathway inhibitor pretreatment. Our data suggest that PRL synergistically augments EGF signaling in T47D breast cancer cells at least in part by lessening EGF-induced EGFR downregulation and that this effect requires PRL-induced ERK activity and threonine phosphorylation of EGFR.

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Identification of a Novel Inhibitor of Mitogen-activated Protein Kinase Kinase

Cited by 2,844 publications

References 38 publications

ERK activity facilitates activation of the S-phase DNA damage checkpoint by modulating ATR function

ERK activity facilitates activation of the S-phase DNA damage checkpoint by modulating ATR function

Up-regulation of thromboxane A2 receptor expression by lipid soluble smoking particles through post-transcriptional mechanisms

Prolactin modulates phosphorylation, signaling and trafficking of epidermal growth factor receptor in human T47D breast cancer cells

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