Chemotherapies that rely on replication-associated DNA damage can affect healthy cells as well as cancer cells, to the detriment of patients. Sweden’s Karolinska Institute is developing DNA repair inhibitors that can select their intended target, leaving normal cells unharmed.
Dr Oliver Mortusewicz is the Principal Researcher and Basic Science Team Leader of the Thomas Helleday Research Team, which sits within the Department of Oncology-Pathology at the Karolinska Institute. He describes how his team is at the forefront of cancer research, supporting novel treatments to improve patients’ experience of chemotherapy.
Describe your research, and what you are trying to achieve in the lab.
Our overarching aim is to develop new targeted therapies, not just for cancers, but also for inflammation, autoimmune diseases and viral infections. We do this by investigating DNA repair and damage signalling pathways, as well as nucleotide metabolism. Specifically for oncology, our objective is to turn cancer defects into cures using the ‘synthetic lethality’ concept. This makes use of the extreme level of DNA damage and dysfunctional redox present in cancer cells by inhibiting the repair of lesions and accelerating further injury to the cell. The huge advantage of this approach is that, compared to existing chemotherapies, therapies should have fewer side effects, hopefully making treatment regimens more comfortable for patients.
Have you had any success? Have any of the treatments made it out of the lab?
Our goal is always to take all our projects to the clinic, and we have already been successful. Currently, we have two Phase I clinical trials underway for karonudib/ OXC-101 – an MTH1 inhibitor candidate – at Karolinska University Hospital.
What are the most common assays you perform in your research, and what challenges accompany them?
Our lab performs a wide variety of tests as part of its drug development workflow, including target engagement assays to make sure the candidate molecule binds to the specific target in the cancer cells.
These happen quite early in the drug discovery workflow and is followed by functional assays – testing a drug’s efficacy in inducing DNA damage – and synergy assays, which investigate if potential anti-cancer compounds work synergistically with approved drugs to increase therapeutic efficacy.
One of the main challenges associated with these assays is that they require the accurate dispensing of candidate compounds and approved therapeutics at extremely low volumes – in the microlitre, nanolitre or even picolitre range – into 384-well plates, which are then seeded with cancer cells.
The huge advantage of this approach is that, compared to existing chemotherapies, therapies should have fewer side effects, hopefully making treatment regimens more comfortable for patients
Manually performing these tasks is extremely complex and tedious, and dispensing such small volumes can be prone to significant variation due to human error. Furthermore, it generally takes too long to be able to assay large numbers of compounds in parallel, meaning it is simply not feasible to perform large-scale studies by hand, as it would significantly impact the team’s productivity.
How did you overcome these challenges? And what results have you seen?
Realising the difficulty of accurately dispensing low volumes of liquid at the scale we needed, we turned to automation to increase our efficiency and throughput. We installed a Tecan D300e Digital Dispenser to automate many of the pipetting steps, offering us the capacity to reliably dispense down to just 11 pl. This has reduced the chance of pipetting errors and inter-well variability, enhancing our assays’ overall reproducibility. Automation now plays a vital role in our lab, speeding up our liquid handling workflow beyond what we previously thought was possible, as well as reducing handson time and freeing up our staff to do other vital tasks in the lab.
Have you employed automation elsewhere in the lab?
We also conduct resazurin assays to test for cell viability, which requires imaging the plates to determine the metabolic activity of the cells. For this, we use fluorescently tagged proteins or immunofluorescence to image the cells, which gives us a better understanding of what is actually happening to them. For example, we can assess the rate of cell proliferation or localisation of repair proteins upon the initiation of DNA damage. We use a Tecan Spark Cyto live cell plate reader to perform real-time imaging and cytometry, such as to carry out automated stain-free cell counting and confluence assessment of a whole microplate.
What’s the next step for your lab?
Recently, we found that one of our anti-cancer molecules is also effective in preventing inflammation, so we are following this lead and venturing out into other areas of research with our drugs. Our automated platforms have transformed how we conduct our research, and we look forward to employing them in further vital research in the future, following wherever the science leads us.
