The Effects of a Novel MEK Inhibitor PD184161 on MEK-ERK Signaling and Growth in Human Liver Cancer

Klein, Patrick; Schmidt, C. Max; Wiesenauer, Chad; Choi, Jennifer; Gage, Earl A.; Yip-Schneider, Michele; Wiebke, Eric A.; Wang, Yufang; Omer, Charles A.; Sebolt–Leopold, Judith S.

doi:10.1593/neo.05373

Cited by 65 publications

(48 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pancreatic BxPc3 xenografts started to grow after the completion of CI-1040-treatment [15]. Furthermore, another MEK inhibitor PD184161 failed to suppress MEK activity in hepatocellular carcinoma xenografts following long term (24 days) and to regress established xenograft tumors [16]. These in vivo studies are consistent with our data (Fig.…”

Section: Discussionsupporting

confidence: 90%

Elevated expression of ERK 2 in human tumor cells chronically treated with PD98059

Kanda

Kanetake

Miyata

2006

Biochemical and Biophysical Research Communications

View full text Add to dashboard Cite

Abbreviations: ERK, extracellular signal-regulated kinase; MAPK, mitogen-activated protein kinase; MEK, MAPK/ERK kinase; siRNA, small interfering RNA; FBS, fetal bovine serum; DMSO, dimethyl sulfoxide; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; MEM, Minimal essential medium; NEAA, non-essential amino acids; BrdU, bromodeoxyuridine. MEK 1 and 2 are the only upstream molecules that are able to activate ERK 1 and 2.Thus, specific inhibition of MEK achieves specific and efficient inactivation of ERK [3,4]. In human cancer cells, ERK activity is frequently elevated than in normal adjacent cells [5]. It has been shown that MEK inhibitors potently blocked the tumor progression in xenografted animal models [6,7]. However, MEK inhibitors did not affect human tumors in clinical trials [8,9].To address the question of how human tumor cells evade the inhibitory action of MEK inhibition at a cellular level, we examined the effects of chronic exposure to PD98059 on human tumor cells. We show here for the first time that the chronic exposure of tumor cells to a MEK inhibitor upregulated the expression of ERK 2, which was involved in the decreased sensitivity of their proliferation to MEK inhibitor-treatment. 4 Materials and MethodsMaterials Anti-MEK 1 polyclonal antibody (12-B), small interfering RNA (siRNA) for human ERK 1 and 2, and non-targeting control siRNA were purchased from Santa Cruz Biotechnologies, Santa Cruz, CA. Anti-phospho-mitogen-activated protein kinase were cultured with PD98059 in all assays, except when otherwise specified.Cell proliferation assay Cells were suspended in either MEM with NEAA or Ham's F-12 medium containing 10% FBS and seeded into 24-well plates at a density of 1  10 4 cells/well in the presence of 0.1% DMSO or 50 M PD98059. After 3 days, the cells were detached with trypsin and counted with the use of a hemocytometer. Cell number without short-period PD98059-treatment was set to 100. 6Labeling index Labeling index was examined to determine the numbers of cells in S-phase using the bromodeoxyuridine (BrdU) In-Situ detection kit ® (BD Biosciences Pharmingen, San Diego, CA) as described before [11]. In brief, cells were seeded into wells of 48-well-culture plates. On the following day, medium was changed to fresh medium containing 10% FBS with either 0.1% DMSO or 50 M PD98059, and culture was continued. After 16 h, cells were pulse-labeled for 4 h with BrdU. Cells were then fixed, treated with 4 M HCl, and uptaken BrdU was visualized with anti-BrdU antibody.At least 500 cells were counted for each well, and labeling indices were determined as labeled nuclei/total nuclei ratios and expressed as percentages. Treatment of cells with siRNA Cells suspended in MEM with NEAA or Ham's F-12medium containing 10% FBS were seeded into 24-well plates (2  10 4 cells/well) and cultured for 20 h. Culture medium was replaced with fresh medium containing 10% FBS.Serum-free medium supplemented with HiPerFect reagent and siRNA at the indicated concentrations were mixed, left for 20 min at room temperatu...

show abstract

Section: Discussionsupporting

confidence: 90%

Elevated expression of ERK 2 in human tumor cells chronically treated with PD98059

Kanda

Kanetake

Miyata

2006

Biochemical and Biophysical Research Communications

View full text Add to dashboard Cite

show abstract

“…increasing evidence suggests that this pathway is abnormally regulated in Hcc and plays a central role in tumorigenesis and the maintenance of tumor growth (30)(31)(32). in addition, targeted inhibition of this pathway has been regarded as an alternative approach for the treatment of Hcc (33,34). our results indicate that TGF-β1 significantly enhances the activation of the MaPK pathway, as evidenced by the phosphorylation of downstream p38 and JnK.…”

Section: Discussionsupporting

confidence: 51%

Lentiviral-mediated Smad4 RNAi promotes SMMC-7721 cell migration by regulation of MMP-2, VEGF and MAPK signaling

Ji¹

2010

Mol Med Rep

View full text Add to dashboard Cite

Abstract. Hepatocellular carcinoma (Hcc) is a highly malignant cancer characterized by rapid progression, easy metastasis and frequent recurrence. Previous studies have shown that the Smad4 signaling pathway plays an important role in the cell growth and apoptosis of Hcc. However, the effect of Smad4 signaling on the invasion and migration of Hcc cells remains unclear. The present study aimed to examine the effects of the transforming growth factor (TGF)-β1-Smad4 signaling pathway on the migration of Hcc cells. lentiviral vectors expressing mirna against Smad4 were constructed to block the expression of Smad4 in Hcc cells, and transwell units were used to investigate the invasive potential of SMMc-7721 cells before and after TGF-β1 treatment. mrna levels of matrix metalloproteinase (MMP)-2 and -9 were analyzed by reverse-transcription Pcr, and concentrations of vascular endothelial growth factor (VeGF), p-JnK, p-p38 and p-erk1/2 proteins were analyzed by Western blotting. The results indicate that TGF-β1 induced cellular invasion in the SMMc-7721 cells. These effects were almost completely blocked by the knockdown of Smad4. reverse-transcription Pcr and Western blot analysis revealed that MMP-2, VeGF, p-JnK and p-p38 were up-regulated by the silencing of Smad4, while the expression of MMP-9 and p-erk1/2 was not affected by Smad4 silencing with or without TGF-β1 stimulation. These findings suggest that TGF-β1-induced SMMc-7721 cell invasion by the up-regulation of MMP-2 and VeGF is Smad4-dependent. The activation of MMP-2 and VeGF may be an important mechanism by which Smad4 is involved in metastasis. TGF-β1-Smad4 signaling may regulate SMMc-7721 cell migration through the activation of the MaPK pathway.

show abstract

“…MEKtargeted treatment has been studied in colon, pancreatic, breast or melanoma tumors (Sebolt-Leopold et al, 1999;Duesbery et al, 2001;Yeh et al, 2007;Haass et al, 2008) and recently in human HCC tumors (Klein et al, 2006). Targeting MEK with PD184161, which has the obvious advantages of solubility and oral bioavailability, in vivo resulted in a significant delay in HCC tumor engraftment and inhibition of early tumor growth.…”

Section: Discussionmentioning

confidence: 99%

“…A drug-targeting ERK activity decreases the incidence of colon carcinoma development in vivo (Sebolt-Leopold et al, 1999). In a recent report, a novel orally active MEK inhibitor, PD184161, has been tested on hepatocellular carcinoma (HCC) xenografts and induced partial antitumoral effects in vivo (Klein et al, 2006). PD184161 significantly suppressed tumor engraftment and initial growth but established tumors were not significantly affected.…”

Section: Introductionmentioning

confidence: 99%

RNAi-mediated ERK2 knockdown inhibits growth of tumor cells in vitro and in vivo

et al. 2008

View full text Add to dashboard Cite

The MAPK MEK/ERK pathway is often upregulated in cancer cells and represents an attractive target for development of anticancer drugs. Only few data concerning the specific functions of ERK1 and 2 are reported in the literature. In this report, we investigated the specific role of ERK1 and 2 in liver tumor growth both in vitro and in vivo. DNA synthesis and cells in S phase analysed by flow cytometry, correlated with strong inhibition of Cdk1 and cyclin E levels, are strongly reduced after exposure to the MEK inhibitor, U0126. We obtained a significant reduction of colony formation in soft agar assays and a reduction in the size of tumor xenografts in nude mice treated with U0126. Then, we could specifically abolished ERK1 or 2 expression by small-interfering RNA (siRNA) and demonstrated that ERK2 knockdown but not ERK1 interferes with the process of replication. Moreover, we found that colony formation and tumor growth in vivo were significantly inhibited by targeting ERK2 using stable chemically modified siRNA. Taken together, our results emphasize the importance of the MEK/ERK pathway in liver cancer cell growth in vitro and in vivo and argue for a crucial role of ERK2 in this regulation.

show abstract

The Effects of a Novel MEK Inhibitor PD184161 on MEK-ERK Signaling and Growth in Human Liver Cancer

Cited by 65 publications

References 54 publications

Elevated expression of ERK 2 in human tumor cells chronically treated with PD98059

Elevated expression of ERK 2 in human tumor cells chronically treated with PD98059

Lentiviral-mediated Smad4 RNAi promotes SMMC-7721 cell migration by regulation of MMP-2, VEGF and MAPK signaling

RNAi-mediated ERK2 knockdown inhibits growth of tumor cells in vitro and in vivo

Contact Info

Product

Resources

About