Poster Presentation 35th Lorne Cancer Conference 2023

Uncovering novel functions of ZEB1 in triple-negative breast cancer   (#245)

Cerys McCool 1 2 3 , Beatriz Perez San Juan 1 2 3 4 , Shabarni Gupta 1 , Christine Chaffer 2 3 4
  1. The Garvan Institute of Medical Research, Sydney, NSW, Australia
  2. St. Vincents Clinical School, UNSW Medicine, Syndey, NSW, Australia
  3. The Kinghorn Cancer Centre, Sydney, NSW, Australia
  4. The Garvan Institute , Sydney, NSW, Australia

Background

ZEB1 is a major driver of triple-negative breast cancer (TNBC) cell plasticity; a process that enables poorly tumorigenic non-cancer-stem cells (CSCs) to transition into the aggressive CSC state, driving therapy resistance and metastasis1–3. Inhibiting ZEB1 is a promising target to eliminate CSCs and prevent metastasis and therapy resistant disease4,5. However, there are currently no targeted therapies for ZEB1, which can in part be attributed to the little work has been done to explore how ZEB1 is regulated to drive these processes. We have recently uncovered that post-translational modifications are a major regulator of ZEB1 subcellular localisation and function. This novel biology highlights how ZEB1 is regulated to drive the CSC state and potential mechanisms in which we can develop therapeutic targets against ZEB1.

 

Aim

To uncover how ZEB1 is regulated in TNBC to drive the CSC state.

 

Methods

I have characterised how ZEB1 is post-translationally modified through co-immunoprecipitation and western blot and will use computational multiplexing to gain insights into cytoplasmic compartmentalisation of ZEB1. I have identified stable interactors of ZEB1 in non-CSC and CSC populations in a TNBC cell line by immunoprecipitating endogenous ZEB1 followed by mass-spectrometry.

 

Results

ZEB1 is expressed at multiple molecular weights spanning 124-280 kDa, representing different PTMs. CSCs and non-CSCs express ZEB1 with different PTMs with restrained subcellular localisations. The ZEB1 interactome in these two cell populations also suggests that ZEB1 has a novel non-canonical function in the cytoplasm.

 

Conclusions

This research defines previously undefined ZEB1 biology highlights the complex mechanisms in which ZEB1 is regulated to drive the CSC state. This fundamental biology will allow us to develop novel strategies to target ZEB1 and sensitise aggressive cancer cells to current chemotherapies. This will have huge clinical benefit for cancers enriched with CSCs, such as TNBC, with the potential to be translated to other cancers where ZEB1 has been shown to drive metastasis and therapy resistance6–14.