Inhibition of the MAP kinase activity suppresses estrogen-induced breast tumor growth both in vitro and in vivo

  • Authors:
    • Kaladhar B. Reddy
    • Selina Glaros
  • View Affiliations

  • Published online on: April 1, 2007     https://doi.org/10.3892/ijo.30.4.971
  • Pages: 971-975
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Abstract

Elevated expression of mitogen-activated protein kinase (Erk/MAPK) has been noted in a significant percentage of primary human breast cancers. To directly assess the importance of Erk/MAPK activation in estrogen (E2)-induced tumor progression, we blocked E2-signaling with MEK-inhibitor CI-1040 and/or tamoxifen (Tam). Our data show that both MEK-inhibitor CI-1040 and Tam blocked E2-induced MAPK phosphorylation and cell proliferation in MCF-7 breast cancer cells in vitro. However, in vivo studies show that anti-tumor efficacy of combining the CI-1040 and Tam was similar to single agent(s). Furthermore, sequential treatment with Tam followed by CI-1040 or CI-1040 followed by Tam did not significantly reduce E2-induced tumor growth. This suggests that the combination of CI-1040 and Tam may not be synergistic in inhibiting E2-induced tumor growth. However, these findings also indicate that MAPK plays a critical role in E2-induced tumor growth, and that this could be a potential therapeutic target to combat hormonally regulated growth in ER-positive tumors.

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April 2007
Volume 30 Issue 4

Print ISSN: 1019-6439
Online ISSN:1791-2423

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APA
Reddy, K.B., & Reddy, K.B. (2007). Inhibition of the MAP kinase activity suppresses estrogen-induced breast tumor growth both in vitro and in vivo. International Journal of Oncology, 30, 971-975. https://doi.org/10.3892/ijo.30.4.971
MLA
Reddy, K. B., Glaros, S."Inhibition of the MAP kinase activity suppresses estrogen-induced breast tumor growth both in vitro and in vivo". International Journal of Oncology 30.4 (2007): 971-975.
Chicago
Reddy, K. B., Glaros, S."Inhibition of the MAP kinase activity suppresses estrogen-induced breast tumor growth both in vitro and in vivo". International Journal of Oncology 30, no. 4 (2007): 971-975. https://doi.org/10.3892/ijo.30.4.971