Genetically Encoded Whole Cell Biosensor for Drug Discovery of HIF‑1 Interaction Inhibitors

The heterodimeric transcription factor, hypoxia inducible
factor-1
(HIF-1), is an important anticancer target as it supports the adaptation
and response of tumors to hypoxia. Here, we optimized the repressed
transactivator yeast two-hybrid system to further develop it as part
of a versatile yeast-based drug discovery platform and validated it
using HIF-1. We demonstrate both fluorescence-based and auxotrophy-based
selections that could detect HIF-1α/HIF-1β dimerization
inhibition. The engineered genetic selection is tunable and able to
differentiate between strong and weak interactions, shows a large
dynamic range, and is stable over different growth phases. Furthermore,
we engineered mechanisms to control for cellular activity and off-target
drug effects. We thoroughly characterized all parts of the biosensor
system and argue this tool will be generally applicable to a wide
array of protein–protein interaction targets. We anticipate
this biosensor will be useful as part of a drug discovery platform,
particularly when screening DNA-encoded new modality drugs.