Single-molecule imaging enables large-scale drug screening

As part of the drug discovery process, researchers must first identify molecules in the body’s cells that help drive disease; then, they must screen candidate drugs that can hit those targets. Now, scientists at Osaka University have found a way to streamline drug discovery using single-molecule tracking, allowing them to explore the effects of many different candidate drugs on a single target molecule.

Building on the team’s large-scale intracellular single-molecule imaging system, referred to as AiSIS, the technology screens new drugs 100 times faster than standard manual techniques, which can be challenging and time-consuming process. The technique has been described in the journal Nature Communications.

The team used their new method to screen drugs that can target the epidermal growth factor receptor (EGFR), a molecule central to the development and progression of various cancers. Because several drugs that block EGFR are already available to treat lung cancer, this was a good way to determine how well their screening approach worked.

“We used a library of over 1000 approved drugs to validate our screening method,” said Daisuke Watanabe, lead author of the study. “We successfully identified all the drugs that are known to target EGFR and are currently used to treat cancer patients. More importantly, we found that the library included seven drugs that until now were not known to affect EGFR.”

The new imaging technique visualises the behaviour of EGFR following treatment with each drug, allowing the researchers to examine how it reacted. For example, it is now possible to see changes in the assembly and disassembly of target molecules in response to drug treatment, a process known as multimer formation.

“Screening using single-molecule imaging provides a new means to discover drugs by observing the movement of biomolecules in cells and the formation of multimers,” said senior author Masahiro Ueda. “This has not been used for drug discovery until now, and it means we should be able to develop new drugs with different mechanisms of action and even repurpose already approved drugs to new targets.”

Because the study demonstrated that the researchers’ method worked as expected using the well-known EGFR target, they can now use this approach to screen drugs that could potentially hit an array of other receptor targets that are closely involved in disease development and progression.

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