Skp1 in lung cancer: clinical significance and therapeutic efficacy of its small molecule inhibitors

Oncotarget. 2015 Oct 27;6(33):34953-67. doi: 10.18632/oncotarget.5547.

Abstract

Skp1 is an essential adaptor protein of the Skp1-Cul1-F-box protein complex and is able to stabilize the conformation of some ubiquitin E3 ligases. However, the role Skp1 plays during tumorigenesis remains unclear and Skp1-targeting agent is lacking. Here we showed that Skp1 was overexpressed in 36/64 (56.3%) of non-small cell lung cancers, and elevated Skp1 was associated with poor prognosis. By structure-based high-throughput virtual screening, we found some Skp1-targeting molecules including a natural compound 6-O-angeloylplenolin (6-OAP). 6-OAP bound Skp1 at sites critical to Skp1-Skp2 interaction, leading to dissociation and proteolysis of oncogenic E3 ligases NIPA, Skp2, and β-TRCP, and accumulation of their substrates Cyclin B1, P27 and E-Cadherin. 6-OAP induced prometaphase arrest and exerted potent anti-lung cancer activity in two murine models and showed low adverse effect. These results indicate that Skp1 is critical to lung cancer pathogenesis, and Skp1 inhibitor inactivates crucial oncogenic E3 ligases and exhibits significant therapeutic potentials.

Keywords: 6-O-angeloylplenolin; Skp1; inhibitors; lung cancer; structure-based high-throughput virtual screening.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Blotting, Western
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Cell Survival / drug effects
  • Female
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • High-Throughput Screening Assays
  • Humans
  • Immunoprecipitation
  • Lactones / chemistry
  • Lactones / pharmacology*
  • Lung Neoplasms / metabolism*
  • Male
  • Mice
  • Mice, Nude
  • Middle Aged
  • RNA, Small Interfering
  • S-Phase Kinase-Associated Proteins / analysis
  • S-Phase Kinase-Associated Proteins / antagonists & inhibitors
  • S-Phase Kinase-Associated Proteins / biosynthesis*
  • Sesquiterpenes / chemistry
  • Sesquiterpenes / pharmacology*
  • Transfection
  • Xenograft Model Antitumor Assays

Substances

  • 6-O-angeloylprenolin
  • Antineoplastic Agents
  • Lactones
  • RNA, Small Interfering
  • S-Phase Kinase-Associated Proteins
  • Sesquiterpenes