Nav: Home

A kiss of death to drug the 'undruggable'

March 13, 2017

Scientists at the University of Dundee have reported a major breakthrough in targeting the causes of many diseases, using a `kiss of death' to destroy proteins which had previously been regarded as `undruggable'.

Much is known about proteins such as Ras and Myc which are known to be culpable in human cancer, and Huntingtin, which causes Huntingdon's disease, but as yet they have proved stubbornly resistant to efforts to find ways of tackling them with drugs.

Now researchers led by Professor Alessio Ciulli in the School of Life Sciences at Dundee have found a way of targeting similar proteins, using a small molecule approach in an unconventional way to target `bad' proteins by binding them to neutralising agents to start a process of degradation, and thereby removing them entirely.

"We know of many proteins which are active in causing diseases, but which we have been unable to block from going `rogue' or to stop them when they do," said Professor Ciulli.

"The major problem is that we have been unable to find the small molecules which can successfully bind to these proteins and at the same time hamper their function. It is a highly complex area - these proteins can often fool regulators within the cell and be extremely difficult to pin down with inhibitors.

"Research in our lab in the past few years has contributed towards establishing a different approach, one that has been theorised for many years but which is only now fully realised by this latest work. Instead of using the small molecule to try and disable the bad protein, we have developed a way of modifying it so that it can be used to attract the neutralising proteins, which then bind to their bad neighbour and act against it, starting a cascade process of degradation.

"Crucially, we have also found that it is not enough for this neutralising protein to sit close to the bad protein, it has to make direct contact with it, to `kiss' it. And not just a little peck, but a real `Gone With The Wind' embrace. We call this a 'kiss of death', as it is the key to ensure the degradation of the bad protein."

Professor Ciulli and colleagues focused their attention on a bivalent chemical degrading molecule called `PROTAC' (Proteolysis-targeting chimeric molecules). They have been able to create the first X-ray crystal structure of a PROTAC bound to both the 'bad' protein and the 'neutralising' agent (an E3 ubiquitin ligase), and found that it can successfully be deployed as a `magnet' to draw the two target proteins together.

"This discovery provides the first ever insights into how PROTACs work and how we can target proteins for degradation in a highly selective manner," said Professor Ciulli.

"This presents a paradigm shift in how we can ensure selective chemical intervention against proteins which we know are factors in causing disease but which until now have been impossible to successfully target. It points towards the possibility of drugging the `undruggable'."

The results of the research are published in the journal Nature Chemical Biology.

The work done by the Dundee team focused on pairing one of the BET bromodomain proteins, BRD4, which is an attractive drug target for cancer, with a selective BRD4 `degrader' called MZ1. They found that MZ1 could pull the two proteins together by folding into itself. Once the two proteins are joined in their `kiss' the interactions between them lead to degradation of the target. They showed how similar proteins BRD2 and BRD3 do not kiss the neutralizing protein as well, and guided by this information they were able to design new degraders that spare those proteins completely from the degradation process. This is important because it elucidates how degrading molecules could be designed in future to minimize off-target effects in ways that may not be possible using conventional inhibitors.

The Dundee team working on the project included postdoctoral researchers in Professor Ciulli's laboratory Morgan Gadd, Andrea Testa, Xavier Lucas and Kwok-Ho Chan, and Wengzhan Chan and Dougie Lamont from the Dundee Fingerprints Proteomics Facility.

Professor Ciulli said there were already promising signs from the pharmaceutical industry of significant investment in this research area.

"We now understand better how to turn inhibitors into degraders. The road to turning degraders into drugs will be long and winding and we cannot get there on our own. It is exciting to see signs of serious commitment from the pharmaceutical industry, which adds to optimism that we will be able to get to a point where we can drug the `undruggable'."
-end-


University of Dundee

Related Proteins Articles:

Designing vaccines from artificial proteins
EPFL scientists have developed a new computational approach to create artificial proteins, which showed promising results in vivo as functional vaccines.
New method to monitor Alzheimer's proteins
IBS-CINAP research team has reported a new method to identify the aggregation state of amyloid beta (Aβ) proteins in solution.
Composing new proteins with artificial intelligence
Scientists have long studied how to improve proteins or design new ones.
Hero proteins are here to save other proteins
Researchers at the University of Tokyo have discovered a new group of proteins, remarkable for their unusual shape and abilities to protect against protein clumps associated with neurodegenerative diseases in lab experiments.
Designer proteins
David Baker, Professor of Biochemistry at the University of Washington to speak at the AAAS 2020 session, 'Synthetic Biology: Digital Design of Living Systems.' Prof.
Gone fishin' -- for proteins
Casting lines into human cells to snag proteins, a team of Montreal researchers has solved a 20-year-old mystery of cell biology.
Coupled proteins
Researchers from Heidelberg University and Sendai University in Japan used new biotechnological methods to study how human cells react to and further process external signals.
Understanding the power of honey through its proteins
Honey is a culinary staple that can be found in kitchens around the world.
How proteins become embedded in a cell membrane
Many proteins with important biological functions are embedded in a biomembrane in the cells of humans and other living organisms.
Finding the proteins that unpack DNA
A new method allows researchers to systematically identify specialized proteins called 'nuclesome displacing factors' that unpack DNA inside the nucleus of a cell, making the usually dense DNA more accessible for gene expression and other functions.
More Proteins News and Proteins Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.