Mechanisms regulating the constitutive activation of the extracellular signal-regulated kinase (ERK) signaling pathway in ovarian cancer and the effect of ribonucleic acid interference for ERK1/2 on cancer cell proliferation.

Abstract

The ERK1/2 MAPK pathway is a critical signaling system that mediates ligand-stimulated signals for the induction of cell proliferation, differentiation, and cell survival. Studies have shown that this pathway is constitutively active in several human malignancies and may be involved in the pathogenesis of these tumors. In the present study we examined the ERK1/2 pathway in cell lines derived from epithelial and granulosa cell tumors, two distinct forms of ovarian cancer. We show that ERK1 and ERK2 are constitutively active and that this activation results from both MAPK kinase-dependent and independent mechanisms and is correlated with elevated BRAF expression. MAPK phosphatase 1 (MKP-1) expression, which is involved in ERK1/2 deactivation, is down-regulated in the cancer cells, thus further contributing to ERK hyperactivity in these cells. Treatment of these cancer cell lines with the proteasome inhibitor ZLLF-CHO increased MKP-1 but not MKP-2 expression and decreased ERK1/2 phosphorylation. More importantly, silencing of ERK1/2 protein expression using RNA interference led to the complete suppression of tumor cell proliferation. These results provide evidence that the ERK pathway plays a major role in ovarian cancer pathogenesis and that down-regulation of this master signaling pathway is highly effective for the inhibition of ovarian tumor growth.

• Authors: Rosemary Steinmetz, Heather A Wagoner, Pingyu Zeng, Jessica R Hammond, Tamara S Hannon, Justin L Meyers, Ora H Pescovitz
• Journal: Molecular endocrinology (Baltimore, Md.) (Mol Endocrinol) Vol. 18 Issue 10 Pg. 2570-82 (Oct 2004) ISSN: 0888-8809 [Print] United States
• PMID: 15243131 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Extracellular Signal-Regulated MAP Kinases
• Mitogen-Activated Protein Kinase 1
• Mitogen-Activated Protein Kinase 3

Topics

• Cell Division
• Enzyme Activation
• Extracellular Signal-Regulated MAP Kinases (metabolism)
• Female
• Humans
• MAP Kinase Signaling System (genetics, physiology)
• Mitogen-Activated Protein Kinase 1 (genetics)
• Mitogen-Activated Protein Kinase 3 (genetics)
• Ovarian Neoplasms (genetics, pathology)
• RNA Interference