TGFβ-dependent induction of interleukin-11 and interleukin-8 involves SMAD and p38 MAPK pathways in breast tumor models with varied bone metastases potential

Academic Article

Abstract

  • We have delineated TGFβ signaling pathways in the production of osteolytic factors interleukin-8 and interleukin-11 in breast cancer cells with different bone metastases potential. Bone seeking MDA-MB-231(hm) cells expressed higher levels of IL-11, but lower levels of IL-8 compared to MDA-MB-231 cells. MCF-7 cells (mainly osteoblastic) did not express IL-8 or IL-11; MDA-MB-468 cells (weakly metastatic) expressed IL-8, but not IL-11. The upregulation of IL-11 and IL-8 was associated with the rapid activation of SMAD2/3 and p38 MAPK through the TGFβ/TGFβR system. Analysis of TGFβ receptors indicated that MCF-7 cells do not express TGFβRII, and MDA-MB-468 cells do not express SMAD4. Inactivation of SMAD4 or p38PMAPK gene via RNAi resulted in the inhibition of IL-11 and IL-8 production in MDA-MB-231(hm) cells; and overexpression of SMAD4 gene resulted in IL-11 production in MDA-MB-468 cells. TGFβ-1 induced SMAD3 translocation to the nuclei in MDA-MB-231, MDA-MB-231(hm) as well as in SMAD4 deficient MDA-MB-468, indicating that an alternate non-canonical pathway could be responsible for TGFβ-1 induced cytokine production in MDA-MB-468 cells. Thus, four breast cancer cell lines used in this study show differential expression and upregulation of the osteolytic factors in response to TGFβ-1 that involves both SMAD pathway, a non-canonical SMAD pathway, as well as p38 MAPK pathways. © 2011 Landes Bioscience.
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    Digital Object Identifier (doi)

    Author List

  • Gupta J; Robbins J; Jilling T; Seth P
  • Start Page

  • 311
  • End Page

  • 316
  • Volume

  • 11
  • Issue

  • 3