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Cooperativity between the polyamine pathway and HER‐2neu in transformation of human mammary epithelial cells in culture: Role of the MAPK pathway
Author(s) -
Manni Andrea,
Wechter Rita,
Verderame Michael F.,
Mauger David
Publication year - 1998
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19980518)76:4<563::aid-ijc20>3.0.co;2-7
Subject(s) - mapk/erk pathway , microbiology and biotechnology , polyamine , chemistry , biology , cancer research , signal transduction , biochemistry
Our experiments were designed to test the cooperativity between the polyamine pathway and HER‐2neu in inducing transformation of human mammary epithelial cells in culture. Using the MCF‐10A breast epithelial cell line, we observed that induction of overexpression of ornithine decarboxylase (ODC) (the first rate‐limiting enzyme in polyamine biosynthesis) markedly potentiated the anchorage‐independent growth stimulating effect of the β2 isoform of neu differentiating factor (NDF) known to activate HER‐2neu in MCF‐10A cells. ODC overexpression, on the other hand, did not enhance growth in liquid culture, thus pointing to a specific effect on transformation rather than proliferation. ODC‐overexpressing MCF‐10A cells exhibited increased MAPK phosphorylation in response to administration of NDF and/or epidermal growth factor (EGF). In contrast, the phosphorylation of the members of the stress‐activated protein kinase cascade p38 and SEK were not affected by ODC overexpression. Of note, in the absence of EGF and NDF, ODC overexpression failed to induce both clonogenicity and MAPK activation. These results suggest that increased polyamine biosynthetic activity critically interacts with HER‐2neu in promoting human mammary cell transformation in culture and that the MAPK cascade is an important mediator of this interaction. If confirmed in future in vivo<0R> studies, our results may identify important new targets for the chemoprevention of human breast cancer. Int. J. Cancer 76:563–570, 1998.© 1998 Wiley‐Liss, Inc.