Targeting endogenous transforming growth factor β receptor signaling in Smad4-deficient human pancreatic carcinoma cells inhibits their invasive phenotype

Gayathri Subramanian, Roderich E. Schwarz, Linda Higgins, Glenn McEnroe, Sarvajit Chakravarty, Sundeep Dugar, Michael Reiss

Research output: Contribution to journalArticle

108 Citations (Scopus)

Abstract

Transforming growth factor-β (TGF-β) suppresses tumor formation by blocking cell cycle progression and maintaining tissue homeostasis. In pancreatic carcinomas, this tumor suppressive activity is often lost by inactivation of the TGF-β-signaling mediator, Smad4. We found that human pancreatic carcinoma cell lines that have undergone deletion of MADH4 constitutively expressed high endogenous levels of phosphorylated receptor-associated Smad proteins (pR-Smad2 and pR-Smad3), whereas Smad4-positive lines did not. These elevated pR-Smad levels could not be attributed to a decreased dephosphorylation rate nor to increased expression of TGF-β type I (TβR-I) or type II (TβR-II) receptors. Although minimal amounts of free bioactive TGF-β1 and TGF-β2 were detected in conditioned medium, treatment with a pan-specific (but not a TGF-β3 specific) TGF-β-neutralizing antibody and with anti-α vβ66 integrin antibody decreased steady-state pSmad2 levels and activation of a TGF-β-inducible reporter gene in neighboring cells, respectively. Thus, activation of TGF-β at the cell surface was responsible for the increased autocrine endogenous and paracrine signaling. Blocking TβR-I activity using a selective kinase inhibitor (SD-093) strongly decreased the in vitro motility and invasiveness of the pancreatic carcinoma cells without affecting their growth characteristics, morphology, or the subcellular distribution of E-cadherin and F-actin. Moreover, exogenous TGF-β strongly stimulated in vitro invasiveness of BxPC-3 cells, an effect that could also be blocked by SD-093. Thus, the motile and invasive properties of Smad4-deficient pancreatic cancer cells are at least partly driven by activation of endogenous TGF-β signaling. Therefore, targeting the TβR-I kinase represents a potentially powerful novel therapeutic approach for the treatment of this disease.

Original languageEnglish (US)
Pages (from-to)5200-5211
Number of pages12
JournalCancer Research
Volume64
Issue number15
DOIs
StatePublished - Aug 1 2004

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Growth Factor Receptors
Transforming Growth Factors
Phenotype
Pancreatic Carcinoma
Phosphotransferases
Autocrine Communication
Paracrine Communication
Smad Proteins
Cadherins
Conditioned Culture Medium
Neutralizing Antibodies
Pancreatic Neoplasms
Reporter Genes
Integrins
Actins
Neoplasms
Cell Cycle
Homeostasis

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Targeting endogenous transforming growth factor β receptor signaling in Smad4-deficient human pancreatic carcinoma cells inhibits their invasive phenotype. / Subramanian, Gayathri; Schwarz, Roderich E.; Higgins, Linda; McEnroe, Glenn; Chakravarty, Sarvajit; Dugar, Sundeep; Reiss, Michael.

In: Cancer Research, Vol. 64, No. 15, 01.08.2004, p. 5200-5211.

Research output: Contribution to journalArticle

Subramanian, Gayathri ; Schwarz, Roderich E. ; Higgins, Linda ; McEnroe, Glenn ; Chakravarty, Sarvajit ; Dugar, Sundeep ; Reiss, Michael. / Targeting endogenous transforming growth factor β receptor signaling in Smad4-deficient human pancreatic carcinoma cells inhibits their invasive phenotype. In: Cancer Research. 2004 ; Vol. 64, No. 15. pp. 5200-5211.
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