Selective vulnerability of colorectal cancer (CRC) organoids to hypoxia-mimetic drug


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Chiara Asselborn1,Kevin Myant1,Alex von Kriegsheim1
1University of Edinburgh

Abstract

Background

Prolyl hydroxylases are most predominantly known for their ability to hydroxylate HIF1a, which constitutes the main effector for restoring cellular oxygen homeostasis. However, recent evidence suggests direct interactions between the three PHD isoforms and members of other signalling pathways. We are interested in PHDs in the context of colorectal cancer (CRC). We aim to identify potential interactions with canonical Wnt signalling, a pathway strongly dysregulated in CRC, and ultimately to investigate the potential use of PHD inhibitors as a treatment option for CRC.

Method

An MTT assay was used to assess the effects of different PHD inhibitors on mouse intestinal organoids modelling CRC. To confirm targets/off-targets of PHD inhibitors, we are implementing an assay on 2D cell lines which maps drug targets using a Cellular Thermal Shift Assay (CETSA) coupled to TMT 10-plex proteome-wide analysis (1).

Results

We found that Molidustat (BAY 85-3934), a PHD2 inhibitor currently in phase III for Renal Anaemia (2), is able to selectively kill colorectal cancer organoids, which harbour a mutation in APC while WT control organoids remain unaffected. APC is one of the main regulators of the canonical Wnt signalling pathway and described to be mutated in over 80% of CRCs.

Conclusion

We have identified a selective vulnerability of APCfl/fl organoids upon treatment with BAY-85, suggesting a potential link between canonical Wnt signalling and PHDs in CRC. The implementation of the CETSA now aims to generate a high-throughput assessment of BAY 85 target engagement in both sensitive and non-sensitive 2D cell lines. This will involve looking at the previously described main target PHD2, but also identifying new direct targets and downstream effects on signalling networks, since all three could be responsible for the observed vulnerability in APC mutants.

(1) Beck, H. et al. ChemMedChem (2018)

(2) Jafari, R. et al. Nat. Protoc. 9, 2100–2122 (2014)