Nodal and Activin belong to the TGF-β superfamily and are important regulators of embryonic stem cell fate. Here we investigated whether Nodal and Activin regulate self-renewal of pancreatic cancer stem cells. Nodal and Activin were hardly detectable in more differentiated pancreatic cancer cells, while cancer stem cells and stroma-derived pancreatic stellate cells markedly overexpressed Nodal and Activin, but not TGF-β. Knockdown or pharmacological inhibition of the Nodal/Activin receptor Alk4/7 in cancer stem cells virtually abrogated their self-renewal capacity and in vivo tumorigenicity, and reversed the resistance of orthotopically engrafted cancer stem cells to gemcitabine. However, engrafted primary human pancreatic cancer tissue with a substantial stroma showed no response due to limited drug delivery. The addition of a stroma-targeting hedgehog pathway inhibitor enhanced delivery of the Nodal/Activin inhibitor and translated into long-term, progression-free survival. Therefore, inhibition of the Alk4/7 pathway, if combined with hedgehog pathway inhibition and gemcitabine, provides a therapeutic strategy for targeting cancer stem cells. © 2011 Elsevier Inc.
Lonardo, E., Hermann, P. C., Mueller, M. T., Huber, S., Balic, A., Miranda-Lorenzo, I., … Heeschen, C. (2011). Nodal/activin signaling drives self-renewal and tumorigenicity of pancreatic cancer stem cells and provides a target for combined drug therapy. Cell Stem Cell, 9(5), 433–446. https://doi.org/10.1016/j.stem.2011.10.001