Oncostatin M-induced growth inhibition and morphological changes of MDA-MB231 breast cancer cells are abolished by blocking the MEK/ERK signaling pathway.
Cytokine oncostatin M (OM) has profound effects on proliferation and differentiation of breast cancer cells. OM treated cells show reduced growth rate and differentiated phenotypes. The mechanisms underlying the OM growth-inhibitory activity in breast cancer cells have not been fully elucidated. In this study, we investigated the OM-elicited signaling pathways in breast cancer cell lines MDA-MB231 and MCF-7. We show that OM rapidly activates the extracellular signal-regulated kinase (ERK) and the signal transducer and activator of transcription (STAT) 1 and 3 in both cell lines. Intriguingly, OM-induced growth inhibition and morphological changes in MDA-MB231 cells are completely abolished by inhibitors to ERK upstream kinase MEK (nitrogen/extracellular-regulated protein kinase kinase), but the MEK inhibitors have little effects on OM growth-inhibitory activity in MCF-7 cells. In addition, expressions of the cyclin kinase inhibitors p21 and p27 are strongly induced by OM in MCF-7 cells, but their expression is only slightly increased by OM in MDA-MB231 cells. These data together demonstrate that the growth-inhibitory activity of OM can be mediated by different signaling pathways in a cell line-specific manner. While the MEK/ERK pathway is the predominant signaling pathway that leads to the growth inhibition of MDA-MB231 cells, activation of additional signaling pathways are necessary for OM to exert its growth-inhibitory activity in MCF-7 cells.
Li
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Department of Veterans Affairs Palo Alto Health Care System, CA 94304, USA.
Ahlborn
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Kraemer
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FB
Liu
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J
D015153:Blotting, Western; D001943:Breast Neoplasms / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects*; D005260:Female; D006801:Humans; D048728:MAP Kinase Kinase Kinase 1; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D053683:Oncostatin M; D010455:Peptides / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000187:drug effects
C508351:OSM protein, human; D010455:Peptides; D053683:Oncostatin M; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human