Rebecca Cook
Faculty Member
Last active: 4/15/2019

Increased malignancy of Neu-induced mammary tumors overexpressing active transforming growth factor beta1.

Muraoka RS, Koh Y, Roebuck LR, Sanders ME, Brantley-Sieders D, Gorska AE, Moses HL, Arteaga CL
Mol Cell Biol. 2003 23 (23): 8691-703

PMID: 14612410 · PMCID: PMC262670 · DOI:10.1128/mcb.23.23.8691-8703.2003

To determine if Neu is dominant over transforming growth factor beta (TGF-beta), we crossed mouse mammary tumor virus (MMTV)-Neu mice with MMTV-TGF-beta1(S223/225) mice expressing active TGF-beta1 in the mammary gland. Bigenic (NT) and Neu-induced mammary tumors developed with a similar latency. The bigenic tumors and their metastases were less proliferative than those occurring in MMTV-Neu mice. However, NT tumors exhibited less apoptosis and were more locally invasive and of higher histological grade. NT mice exhibited more circulating tumor cells and lung metastases than Neu mice, while NT tumors contained higher levels of phosphorylated (active) Smad2, Akt, mitogen-activated protein kinase (MAPK), and p38, as well as vimentin content and Rac1 activity in situ than tumors expressing Neu alone. Ex vivo, NT cells exhibited higher levels of P-Akt and P-MAPK than Neu cells. These were inhibited by the TGF-beta inhibitor-soluble TGF-beta type II receptor (TbetaRII:Fc), suggesting they were activated by autocrine TGF-beta. TGF-beta stimulated migration of Neu cells into surrounding matrix, while the soluble TGF-beta inhibitor abrogated motility and invasiveness of NT cells. These data suggest that (i) the antimitogenic and prometastatic effects of TGF-beta can exist simultaneously and (ii) Neu does not abrogate TGF-beta-mediated antiproliferative action but can synergize with TGF-beta in accelerating metastatic tumor progression.

MeSH Terms (14)

Animals Apoptosis Cell Division Crosses, Genetic Female Gene Expression Genes, erbB-2 Mammary Neoplasms, Experimental Mice Mice, Mutant Strains Mice, Transgenic Neoplasm Invasiveness Transforming Growth Factor beta Transforming Growth Factor beta1

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