WNT-mediated signaling relay in stem cells and oncogenesis - from basic biology to applications

The in vivo tumor suppressor role of the FZD E3 ubiquitin ligases RNF43 & ZNRF3

Early stage researcher 11 (ESR11) project

Supervision: Bon-Kyoung Koo

Lab webpage:  http://www.stemcells.cam.ac.uk/researchers/principal-investigators/bon-kyoung-koo

Aim:
Understanding the role of FZD E3s - RNF43 and ZNRF3 - in tumorigenesis

Methodology:
ESR11 will establish an RNF43/ZNRF3 (R&Z)-null tumour model by crossing conditional alleles with appropriate tissue-specific Cre transgenic lines. After R&Z deletion, target organs will be analysed for time of onset, size and histology of tumours. ESR11 will examine whether tumour formation is driven by activation of WNT-b-catenin signaling due to downregulation of FZD as exemplified in the intestine (international secondment: Maurice, collaboration Bryja). ESR11 will identify the responsible FZD receptor in tissue-specific R&Z-null tumors using lentiviral knockdown in primary 3D organoid cultures derived from established tumours. ESR11 will screen for compounds that bind and inhibit key FZD receptors to prevent RNF43-null-mediated tumourigenesis (private sector secondment: Isogenica, collaboration Pepscan) and will investigate the use of WNT secretion inhibitors for growth inhibition of R&Z-null intestinal tumour cells.

Collaborators:
Maurice, Bryja, Isogenica, Pepscan

Project goals:
ESR11 will characterize the R&Z tumour suppressor role in diverse tissues and identify candidate tissue-specific drug targets for R&Z-mutant tumours.

Risk assessment and contingency plans:
Training of the fellow will not be in jeopardy, as the the lab has extensive experience with mouse tumorigenesis and key systems are established. FZD inhibiting compounds will be tested and compared in vitro, in cells and in animals.

Key publications:

  1. Koo BK, Spit M, Jordens I, Low TY, Stange DE, van de Wetering M, van Es JH, Mohammed S, Heck AJR, Maurice MM, Clevers H (2012) Tumour suppressor RNF43 is a stem cell E3 ligase that induces endocytosis of Wnt receptors. Nature 488(7413):665-9.
  2. Koo BK*, Stange DE*, Sato T, Karthaus W, Farin H, Huch M, van Es JH, Clevers H (2011) *equal contribution. Controlled gene expression in primary Lgr5 organoid cultures Nature Methods 4;9(1):81-3.
  3. de Lau W, Barker N, Low TY, Koo BK, Li VS, Teunissen H, Kujala P, Haegebarth A, Peters PJ, van de Wetering M, Stange DE, van Es JE, Guardavaccaro D, Schasfoort RB, Mohri Y, Nishimori K, Mohammed S, Heck AJ, Clevers H (2011) Lgr5 homologues associate with Wnt receptors and mediate Rspondin signalling. Nature 4;476(7360):293-7.