RNAi screen reveals synthetic lethality between cyclin G-associated kinase and FBXW7 by inducing aberrant mitoses

Br J Cancer. 2017 Sep 26;117(7):954-964. doi: 10.1038/bjc.2017.277. Epub 2017 Aug 22.

Abstract

Background: F-box and WD40 repeat domain-containing 7 (FBXW7) is an E3 ubiquitin ligase involved in the ubiquitination and degradation of multiple oncogenic substrates. The tumour suppressor function is frequently lost in multiple cancers through genetic deletion and mutations in a broad range of tumours. Loss of FBXW7 functionality results in the stabilisation of multiple major oncoproteins, culminating in increased cellular proliferation and pro-survival pathways, cell cycle deregulation, chromosomal instability and altered metabolism. Currently, there is no therapy to specifically target FBXW7-deficient tumours.

Methods: We performed a siRNA kinome screen to identify synthetically lethal hits to FBXW7 deficiency.

Results: We identified and validated cyclin G-associated kinase (GAK) as a potential new therapeutic target. Combined loss of FBXW7 and GAK caused cell cycle defects, formation of multipolar mitoses and the induction of apoptosis. The synthetic lethal mechanism appears to be independent of clathrin-mediated receptor endocytosis function of GAK.

Conclusions: These data suggest a putative therapeutic strategy for a large number of different types of human cancers with FBXW7 loss, many of which have a paucity of molecular abnormalities and treatment options.

Publication types

  • Validation Study

MeSH terms

  • Apoptosis / genetics
  • Cell Cycle / genetics
  • Cell Cycle Proteins / deficiency*
  • Cell Cycle Proteins / genetics*
  • Cell Line, Tumor
  • Clathrin / antagonists & inhibitors
  • F-Box Proteins / genetics*
  • F-Box-WD Repeat-Containing Protein 7
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Mitosis / genetics*
  • Neoplasms / genetics*
  • Protein Serine-Threonine Kinases / genetics*
  • RNA Interference
  • RNA, Small Interfering
  • Sulfonamides / pharmacology
  • Synthetic Lethal Mutations
  • Thiazolidines / pharmacology
  • Ubiquitin-Protein Ligases / deficiency*
  • Ubiquitin-Protein Ligases / genetics*

Substances

  • Cell Cycle Proteins
  • Clathrin
  • F-Box Proteins
  • F-Box-WD Repeat-Containing Protein 7
  • FBXW7 protein, human
  • Intracellular Signaling Peptides and Proteins
  • RNA, Small Interfering
  • Sulfonamides
  • Thiazolidines
  • pitstop 2
  • Ubiquitin-Protein Ligases
  • GAK protein, human
  • Protein Serine-Threonine Kinases