Cucurbitacin B inhibits the stemness and metastatic abilities of NSCLC via downregulation of canonical Wnt/β-catenin signaling axis

Sci Rep. 2016 Feb 24:6:21860. doi: 10.1038/srep21860.

Abstract

Lack of effective anti-metastatic drugs creates a major hurdle for metastatic lung cancer therapy. For successful lung cancer treatment, there is a strong need of newer therapeutics with metastasis-inhibitory potential. In the present study, we determined the anti-metastatic and anti-angiogenic potential of a natural plant triterpenoid, Cucurbitacin B (CuB) against non-small cell lung cancer (NSCLC) both in vitro and in vivo. CuB demonstrated a strong anti-migratory and anti-invasive ability against metastatic NSCLC at nanomolar concentrations. CuB also showed significant tumor angiogenesis-inhibitory effects as evidenced by the inhibition of migratory, invasive and tube-forming capacities of human umbilical vein endothelial cells. CuB-mediated inhibition of angiogenesis was validated by the inhibition of pre-existing vasculature in chick embryo chorio-allantoic membrane and matrigel plugs. Similarly, CuB inhibited the migratory behavior of TGF-β1-induced experimental EMT model. The CuB-mediated inhibition of metastasis and angiogenesis was attributable to the downregulation of Wnt/β-catenin signaling axis, validated by siRNA-knockdown of Wnt3 and Wnt3a. The CuB-mediated downregulation of Wnt/β-catenin signaling was also validated using 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis model in vivo. Collectively, our findings suggest that CuB inhibited the metastatic abilities of NSCLC through the inhibition of Wnt/β-catenin signaling axis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Animals
  • Blotting, Western
  • Carcinoma, Non-Small-Cell Lung / chemically induced
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Cell Transformation, Neoplastic / drug effects
  • Down-Regulation / drug effects*
  • Epithelial-Mesenchymal Transition / drug effects
  • Female
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Immunoprecipitation
  • Lung Neoplasms / chemically induced
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Mice
  • Microscopy, Fluorescence
  • Neovascularization, Physiologic / drug effects
  • Nitrosamines / toxicity
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Transforming Growth Factor beta1 / pharmacology
  • Triterpenes / toxicity*
  • Wnt Signaling Pathway / drug effects*
  • Wnt3 Protein / antagonists & inhibitors
  • Wnt3 Protein / genetics
  • Wnt3 Protein / metabolism
  • Wnt3A Protein / antagonists & inhibitors
  • Wnt3A Protein / genetics
  • Wnt3A Protein / metabolism
  • beta Catenin / metabolism*

Substances

  • Nitrosamines
  • RNA, Small Interfering
  • Transforming Growth Factor beta1
  • Triterpenes
  • Wnt3 Protein
  • Wnt3A Protein
  • beta Catenin
  • cucurbitacin B
  • 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone