An active ingredient in eye drops that were being developed for the treatment of a form of eye disease has shown promise for treating an aggressive form of blood cancer. Scientists at the Wellcome Sanger Institute, University of Cambridge, University of Nottingham and their collaborators have found that this compound, which targets an essential cancer gene, could kill leukaemia cells without harming non-leukemic blood cells.
The results, published today (19 December) in Nature Communications reveal a potential new treatment approach for an aggressive blood cancer with a poor prognosis.
Acute myeloid leukaemia (AML) is a form of blood cancer that affects people of all ages, often requiring months of intensive chemotherapy and prolonged hospital admissions. It develops in cells in the bone marrow crowding out the healthy cells, in turn leading to life-threatening infections and bleeding.
Mainstream AML treatments have remained unchanged for over thirty years, with the current treatment being chemotherapy, and the majority of people's cancer cannot be cured. A subtype of AML, driven by rearrangements in the MLL gene has a particularly bad prognosis.
In a previous study, researchers at the Sanger Institute developed an approach, based on CRISPR gene editing technology, which helped them identify more than 400 genes as possible therapeutic targets for different subtypes of AML. One of the genes, SRPK1, was found to be essential for the growth of MLL-rearranged AML. SRPK1 is involved in a process called RNA splicing, which prepares RNA for translation into proteins, the molecules that conduct the majority of normal cellular processes, including growth and proliferation.
In a new study, Sanger Institute researchers and their collaborators set out to work out how inhibition of SRPK1 can kill AML cells and whether it has therapeutic potential in this disease. They first showed that genetic disruption of SRPK1 stopped the growth of MLL-rearranged AML cells and then went on to study the compound SPHINX31, an inhibitor of SRPK1, which was being used to develop an eye drop treatment for retinal neovascular disease - the growth of new blood vessels on the retinal surface that bleed spontaneously and cause vision loss.
The team found that the compound strongly inhibited the growth of several MLL-rearranged AML cell lines, but did not inhibit the growth of normal blood stem cells. They then transplanted patient-derived human AML cells into immunocompromised mice and treated them with the compound. Strikingly, the growth of AML cells was strongly inhibited and the mice did not show any noticeable side effects.
Dr George Vassiliou, joint leader of the research from the Wellcome Sanger Institute and the Wellcome-MRC Cambridge Stem Cell Institute, said: "We have discovered that inhibiting a key gene with a compound being developed for an eye condition can stop the growth of an aggressive form of acute myeloid leukaemia without harming healthy cells. This shows promise as a potential approach for treating this aggressive leukaemia in humans."
SRPK1 controls the splicing* of RNA in the production of new proteins. An example of a gene that is affected when SRPK1 is blocked is BRD4, a well-known gene that maintains AML. Inhibiting SRPK1 causes the main form of BRD4 to switch to another form, a change that is detrimental to AML growth.
Dr Konstantinos Tzelepis, joint lead author from the Wellcome Sanger Institute and University of Cambridge, said: "Our study describes a novel mechanism required for leukaemia cell survival and highlights the therapeutic potential of SRPK1 inhibition in an aggressive type of AML. Targeting this mechanism may be effective in other cancers where BRD4 and SRPK1 play a role, such as metastatic breast cancer."
Professor David Bates, from the University of Nottingham and co-founder of biotech company Exonate, which develops eye drops for retinal diseases, said: "When Dr Vassiliou told me that SRPK1 was required for the survival of a form of AML, I immediately wanted to work with him to find out if our inhibitors could actually stop the leukaemia cells growing. The fact that the compound worked so effectively bodes well for its potential development as a new therapy for leukaemia. It will take some time, but there is real promise for a new treatment on the horizon for patients with this aggressive cancer."
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Notes to Editors:
*Splicing is the preparation of RNA for the production of proteins. From the strand of RNA, non-coding regions (introns) are removed, leaving the coding regions (exons) which are needed for the assembly of amino acids to form proteins.
Publication:
Konstantinos Tzelepis et al. (2018) SRPK1 maintains acute myeloid leukemia through effects on isoform usage of epigenetic regulators including BRD4. Nature Communications. DOI: 10.1038/s41467-018-07620-0
Funding:
This study was supported by Wellcome (WT098051 and RG94424), the Kay Kendall Leukaemia Fund (KKL920), Cancer Research UK and Exonate Ltd.
Selected websites:
University of Nottingham
The University of Nottingham is a research-intensive university with a proud heritage, consistently ranked among the world's top 100. Studying at the University of Nottingham is a life-changing experience and we pride ourselves on unlocking the potential of our 44,000 students - Nottingham was named both Sports and International University of the Year in the 2019 Times and Sunday Times Good University Guide, was awarded gold in the TEF 2017and features in the top 20 of all three major UK rankings. We have a pioneering spirit, expressed in the vision of our founder Sir Jesse Boot, which has seen us lead the way in establishing campuses in China and Malaysia - part of a globally connected network of education, research and industrial engagement. We are ranked eighth for research power in the UK according to REF 2014. We have six beacons of research excellence helping to transform lives and change the world; we are also a major employer, proud of our Athena SWAN silver award, and a key industry partner- locally and globally.
Wellcome Trust/Cancer Research UK Gurdon Institute
Named after its co-founder, Nobel Laureate Sir John Gurdon, the Gurdon Institute is a world-leading centre for research into the fundamental processes of biology and development, and how these go wrong in diseases such as cancer. More than 240 scientists work in the Institute's purpose-built laboratories on projects ranging from breast cancer and brain development to liver regeneration and leukaemia. Many have made pioneering contributions to the fields of basic cell biology, cellular reprogramming, epigenetics and DNA repair.
Wellcome-MRC Cambridge Stem Cell Institute
The Wellcome - MRC Cambridge Stem Cell Institute is a world-leading centre for stem cell research with a mission to transform human health through a deep understanding of normal and pathological stem cell behaviour. Bringing together biological, clinical and physical scientists operating across a range of tissue types and at multiple scales, we explore the commonalities and differences in stem cell biology in a cohesive and inter-disciplinary manner. In 2018, we will relocate to a new purpose-built home on the Cambridge Biomedical Campus. Housing over 350 researchers, including a critical mass of clinician scientists, the Institute will integrate with neighbouring disease-focused research institutes and also act as a hub for the wider stem cell community in Cambridge. http://www.stemcells.cam.ac.uk
About the University of Cambridge
The mission of the University of Cambridge is to contribute to society through the pursuit of education, learning and research at the highest international levels of excellence. To date, 98 affiliates of the University have won the Nobel Prize. Founded in 1209, the University comprises 31 autonomous Colleges, which admit undergraduates and provide small-group tuition, and 150 departments, faculties and institutions. Cambridge is a global university. Its 19,000 student body includes 3,700 international students from 120 countries. Cambridge researchers collaborate with colleagues worldwide, and the University has established larger-scale partnerships in Asia, Africa and America. The University sits at the heart of the 'Cambridge cluster', which employs 60,000 people and has in excess of £12 billion in turnover generated annually by the 4,700 knowledge-intensive firms in and around the city. The city publishes 341 patents per 100,000 residents. http://www.cam.ac.uk
The Wellcome Sanger Institute
The Wellcome Sanger Institute is one of the world's leading genome centres. Through its ability to conduct research at scale, it is able to engage in bold and long-term exploratory projects that are designed to influence and empower medical science globally. Institute research findings, generated through its own research programmes and through its leading role in international consortia, are being used to develop new diagnostics and treatments for human disease. To celebrate its 25th year in 2018, the Institute is sequencing 25 new genomes of species in the UK. Find out more at http://www.sanger.ac.uk or follow @sangerinstitute
Wellcome
Wellcome exists to improve health for everyone by helping great ideas to thrive. We're a global charitable foundation, both politically and financially independent. We support scientists and researchers, take on big problems, fuel imaginations and spark debate. http://www.wellcome.ac.uk
Journal
Nature Communications