MEK inhibition suppresses K-Ras wild-type cholangiocarcinoma in vitro and in vivo via inhibiting cell proliferation and modulating tumor microenvironment

Cell Death Dis. 2019 Feb 11;10(2):120. doi: 10.1038/s41419-019-1389-4.

Abstract

PD901, a MEK inhibitor, has been demonstrated of therapeutic efficacy against cholangiocarcinoma (CCA) harboring K-Ras oncogenic mutations. However, most CCA exhibit no K-Ras mutations. In the current study, we investigated the therapeutic potential of PD901, either alone or in combination with the pan-mTOR inhibitor MLN0128, for the treatment of K-Ras wild-type CCA in vitro using human CCA cell lines, and in vivo using AKT/YapS127A CCA mouse model. We discovered that in vitro, PD901 treatment strongly inhibited CCA cell proliferation, and combined PD901 and MLN0128 therapy further increased growth inhibition. In vivo, treatment of PD901 alone triggered tumor regression, which was not further increased when the two drugs were administered simultaneously. Mechanistically, PD901 efficiently hampered ERK activation in vitro and in vivo, leading to strong inhibition of CCA tumor cell cycle progression. Intriguingly, we discovered that PD901, but not MLN0128 treatment resulted in changes affecting the vasculature and cancer-associated fibroblasts in AKT/YapS127A mouse lesions. It led to the decreased hypoxia within tumor lesions, which may further enhance the anti-cell proliferation activities of PD901. Altogether, our study demonstrates that MEK inhibitors could be effective for the treatment of K-Ras wild-type CCA via inhibiting cell proliferation and modulating tumor microenvironment.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Benzoxazoles / pharmacology
  • Benzoxazoles / therapeutic use
  • Cell Cycle Checkpoints / drug effects
  • Cell Hypoxia
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • Cholangiocarcinoma / drug therapy
  • Cholangiocarcinoma / metabolism
  • Cholangiocarcinoma / pathology
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Female
  • Humans
  • Liver / pathology
  • MAP Kinase Kinase Kinases / antagonists & inhibitors
  • MAP Kinase Kinase Kinases / metabolism*
  • Mice
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Kinase Inhibitors / therapeutic use
  • Proto-Oncogene Proteins c-akt / metabolism
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • Pyrimidines / pharmacology
  • Pyrimidines / therapeutic use
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / metabolism
  • Tumor Microenvironment / drug effects*

Substances

  • Benzoxazoles
  • Protein Kinase Inhibitors
  • Pyrimidines
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • Extracellular Signal-Regulated MAP Kinases
  • MAP Kinase Kinase Kinases
  • Proto-Oncogene Proteins p21(ras)
  • sapanisertib