Novel small molecule XPO1/CRM1 inhibitors induce nuclear accumulation of TP53, phosphorylated MAPK and apoptosis in human melanoma cells

PLoS One. 2014 Jul 24;9(7):e102983. doi: 10.1371/journal.pone.0102983. eCollection 2014.

Abstract

XPO1/CRM1 is a key nuclear exporter protein that mediates translocation of numerous cellular regulatory proteins. We investigated whether XPO1 is a potential therapeutic target in melanoma using novel selective inhibitors of nuclear export (SINE). In vitro effects of SINE on cell growth and apoptosis were measured by MTS assay and flow cytometry [Annexin V/propidium iodide (PI)], respectively in human metastatic melanoma cell lines. Immunoblot analysis was used to measure nuclear localization of key cellular proteins. The in vivo activity of oral SINE was evaluated in NOD/SCID mice bearing A375 or CHL-1 human melanoma xenografts. SINE compounds induced cytostatic and pro-apoptotic effects in both BRAF wild type and mutant (V600E) cell lines at nanomolar concentrations. The cytostatic and pro-apoptotic effects of XPO1 inhibition were associated with nuclear accumulation of TP53, and CDKN1A induction in the A375 cell line with wild type TP53, while pMAPK accumulated in the nucleus regardless of TP53 status. The orally bioavailable KPT-276 and KPT-330 compounds significantly inhibited growth of A375 (p<0.0001) and CHL-1 (p = 0.0087) human melanoma cell lines in vivo at well tolerated doses. Inhibition of XPO1 using SINE represents a potential therapeutic approach for melanoma across cells with diverse molecular phenotypes by promoting growth inhibition and apoptosis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Cell Cycle / drug effects
  • Cell Line, Tumor
  • Cell Nucleus / drug effects
  • Cell Nucleus / metabolism
  • Cell Proliferation / drug effects
  • Cyclin-Dependent Kinase Inhibitor p21 / antagonists & inhibitors
  • Cyclin-Dependent Kinase Inhibitor p21 / genetics
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Karyopherins / antagonists & inhibitors*
  • Karyopherins / genetics
  • Karyopherins / metabolism
  • Melanoma / drug therapy*
  • Melanoma / genetics
  • Melanoma / metabolism
  • Melanoma / pathology
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Mitogen-Activated Protein Kinases / genetics
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphorylation / drug effects
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins B-raf / metabolism
  • Receptors, Cytoplasmic and Nuclear / antagonists & inhibitors*
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Signal Transduction
  • Skin Neoplasms / drug therapy*
  • Skin Neoplasms / genetics
  • Skin Neoplasms / metabolism
  • Skin Neoplasms / pathology
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology*
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Karyopherins
  • Receptors, Cytoplasmic and Nuclear
  • Small Molecule Libraries
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • exportin 1 protein
  • Braf protein, mouse
  • Proto-Oncogene Proteins B-raf
  • Mitogen-Activated Protein Kinases