TGF-β autocrine pathway and MAPK signaling promote cell invasiveness and in vivo mammary adenocarcinoma tumor progression

  • Authors:
    • María Cecilia Daroqui
    • Paula Vazquez
    • Elisa Bal de Kier Joffé
    • Andrei V. Bakin
    • Lydia I. Puricelli
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  • Published online on: May 14, 2012     https://doi.org/10.3892/or.2012.1813
  • Pages: 567-575
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Abstract

Breast cancer progression and metastasis have been linked to abnormal signaling by transforming growth factor-β (TGF-β) cytokines. In early-stage breast cancers, TGF-β exhibits tumor suppressor activity by repressing cell proliferation and inducing cell death, whereas in advanced-stage tumors, TGF-β promotes invasion and metastatic dissemination. The molecular mechanisms underlying pro-oncogenic activities of TGF-β are not fully understood. The present study validates the role of TGF-β signaling in cancer progression and explores mediators of pro-oncogenic TGF-β activities using the LM3 mammary adenocarcinoma cell line, derived from a spontaneous murine mammary adenocarcinoma. Expression of kinase-inactive TGF-β receptors decreased both basal and TGF-β-induced invasion. Analysis of signal transduction mediators showed that p38MAPK and MEK contribute to TGF-β stimulation of cell motility and invasion. TGF-β disrupted the epithelial actin structures supporting cell-cell adhesions, and increased linear actin filaments. Moreover, MEK and p38MAPK pathways showed opposite effects on actin remodeling in response to TGF-β. Blockade of Raf-MEK signaling enhanced TGF-β induction of actin stress-fibers whereas p38MAPK inhibitors blocked this effect. A novel observation was made that TGF-β rapidly activates the actin nucleation Arp2/3 complex. In addition, TGF-β stimulated matrix metalloproteinase MMP-9 secretion via a MAPK-independent pathway. Experiments using syngeneic mice showed that kinase-inactive TGF-β receptors inhibit the first stages of LM3 tumor growth in vivo. Our studies demonstrate that autocrine TGF-β signaling contributes to the invasive behavior of mammary carcinoma cells. Moreover, we show that both MAPK-dependent and -independent pathways are necessary for TGF-β-induced effects. Therefore, MEK-ERK and p38 MAPK pathways are potential venues for therapeutic intervention in pro-oncogenic TGF-β signaling.
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August 2012
Volume 28 Issue 2

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Daroqui MC, Vazquez P, Bal de Kier Joffé E, Bakin AV and Puricelli LI: TGF-β autocrine pathway and MAPK signaling promote cell invasiveness and in vivo mammary adenocarcinoma tumor progression. Oncol Rep 28: 567-575, 2012
APA
Daroqui, M.C., Vazquez, P., Bal de Kier Joffé, E., Bakin, A.V., & Puricelli, L.I. (2012). TGF-β autocrine pathway and MAPK signaling promote cell invasiveness and in vivo mammary adenocarcinoma tumor progression. Oncology Reports, 28, 567-575. https://doi.org/10.3892/or.2012.1813
MLA
Daroqui, M. C., Vazquez, P., Bal de Kier Joffé, E., Bakin, A. V., Puricelli, L. I."TGF-β autocrine pathway and MAPK signaling promote cell invasiveness and in vivo mammary adenocarcinoma tumor progression". Oncology Reports 28.2 (2012): 567-575.
Chicago
Daroqui, M. C., Vazquez, P., Bal de Kier Joffé, E., Bakin, A. V., Puricelli, L. I."TGF-β autocrine pathway and MAPK signaling promote cell invasiveness and in vivo mammary adenocarcinoma tumor progression". Oncology Reports 28, no. 2 (2012): 567-575. https://doi.org/10.3892/or.2012.1813