CRISPR Screens Identify Candidate Therapeutic Targets in Leukemia

What have your Ph.D. studies focused on?

"Our goal has always been to develop new treatments for acute myeloid leukemia (AML), a type of blood cancer where patients typically have a poor prognosis. Currently, there are very few existing therapies that are both effective and exhibit low toxicities. Our approach was to focus on eradicating leukemia stem cells, which are known to persist after chemotherapy and can lead to relapse in patients. With this focus in mind, we used a technique called CRISPR/Cas9 screening, a gene editing research tool, to identify different vulnerabilities within AML that could translate into potential therapeutic targets.

In my thesis, we covered four different projects that led us to explore different fields of biology, with a general focus on exploring cell surface receptors in leukemia cells. These receptors allow leukemia cells to interact with their microenvironment and are accessible through antibody-mediated targeting, making them a promising therapeutic target. Some of the studied proteins were involved in glucose and iron metabolism, immune evasion, and chemotactic cytokine regulation. Cytokines are small signaling proteins secreted by cells that can activate host immune responses, play a crucial role in biological processes like wound healing, and can also contribute to the development of diseases like cancer.

Our research expanded beyond a narrow niche of leukemia research, instead investigating it from different angles and utilizing a range of AML models including cell lines, animal models, and patient-derived material, as well as multiomic techniques, including deep sequencing, RNA sequencing and mass spectrometry. One of the findings that I found most exciting, was that through a combination treatment targeting two metabolic pathways, we were able to eradicate AML cells in patient samples. This was a combination that had never been tested before and we found it to be specifically sensitive in one patient group. So just the idea of knowing that perhaps this could be something that could be used to help others, maybe in combination with treatments that already exist (chemotherapy or other agents), and could give them some sort of a clinical advantage, was very exciting,” explains Maria Rodriguez Zabala.

Can you tell us about the cover of your thesis?

“The cover, I cannot take any credit for. I was lost when it came to the design, I could not come up with something that could represent the research done. I remember I was talking to a very creative friend, and she just asked me, “What art style do you like?” and “Tell me the main elements about your research.” From my responses, she put the whole thing together in about 30 minutes, and I think she did an excellent job with the design. 

The idea is that we have leukemia cells in the bloodstream going into the House of CRISPR - a metaphorical garage for genetic repair. The blood cancer cells enter the garage, and then by disrupting these four genes, which have been essential to my thesis, the blood cells come out of the garage on the other side, looking like healthy cells. On the back cover, we have a battlefield where we have healthy cells beating up the leukemia cells. Only the healthy cells are carrying all the weapons, representing the tools that researchers are using now to combat the disease,” describes Maria.

How did you end up doing a Ph.D. at Lund Stem Cell Center?

“I'm originally from Spain, where I lived for the first 18 years of my life. For the majority of my adult life though, I've lived abroad. When I was 18, I moved to London to study at University College London (UCL), where I earned both my bachelor’s and my master’s degrees in human genetics.

When doing my master's thesis project, that's when I became interested in Cancer Research. I decided to explore that a bit further, but I was undecided about whether a Ph.D. was the right path for me. So, first I decided to take a little break after my master’s studies. I went back home to Madrid and worked there as a research assistant in a research hospital where I worked with genetics. At that point, I realized that I wanted to pursue a Ph.D., as I felt that I had acquired the maturity needed to take on such a challenging task. 

I ended up here in Sweden completely by chance. I was going to go in another direction when one of my friends from the lab received this flyer advertising 16 Ph.D. positions as part of the CanFaster program. The program is an EU-funded program, and one of the positions was in my supervisors’ group. I read through the description of the project, and I felt like it was very much written for me. I applied without really knowing what would happen, went through the interviews, and got the position. At that time, I didn’t even know where Lund was, I knew about Stockholm, so I searched for it on Google, looked at some photos of Lund, and I thought, this could be an exciting adventure. So that's how it happened, quite by chance I would say,” notes.

What have you found the most enjoyable during your Ph.D. studies?

“For me, and probably most scientists, the most enjoyable part is the thrill you get when you feel you have made a little breakthrough. Even though it might be small in the moment, you go to bed with the feeling that nobody else in the world knows this, and you can do something for someone. I included a quote about this in the thesis:

"The joy of discovery is the fuel that drives scientific progress, and the thrill of unlocking nature's mysteries is unparalleled” - Francis Crick. This quote really speaks to me, and I believe this feeling is one of the main drivers of the work scientists do.

“I have also really enjoyed the people that I've met along the way during my time as a Ph.D. student. They have made a huge difference during the process. As it is with most jobs, we spend so much time in the lab, and for me, the whole department has been very welcoming. We also have many groups working with leukemia, so we quite often meet together, and I have found that helpful. Being part of the CanFaster program has also opened many new doors. They have some great events, resources, and networking opportunities, for example, networking meetings over breakfast where we discussed how to prepare for interviews, journal clubs, or team-building activities. I feel like I gained very good friends throughout this time,” highlights Maria.

What has been the most challenging aspect?

“My time here in Lund has been fun. I came here thinking this was going to last for four years, and it ended up taking longer which is something I’ve noticed that tends to happen when you work with animal models and relatively challenging projects. Overall, though, I have enjoyed the Ph.D. process, and looking back I would do it all over again. However, it has come with a lot of roadblocks and stressful times. There's been a fair share of stressful, very long nights in the lab, sacrificing weekends, and so on. Though of course, you get the reward of moving forward with your project from that.

Perhaps the most challenging aspect of the Ph.D. has been the publication process. It felt like doing the research was less than half of the process. It was mostly about finding the right journal and I wish that things could be slightly different in academia. That the path was a little more streamlined and that the data could be made available to the right people, other scientists, and much quicker,” says Maria.

What are your plans following your Ph.D. defense?

“Nothing is set in stone yet. I’ve realized that despite the many wonderful things that come from continuing in academia – the freedom and the excitement of driving your own project – I just think it's not quite aligning with what I want for the future. Mainly, I feel that today’s publication pressures make research feel less about doing good research and prioritizing what will ultimately help patients. So, for now, at least, I want to move into the industry, where I can conduct research with a more translational focus, and most likely move towards a small company, maybe a startup or something similar to start. For now, I will likely be moving to the USA, but I don't rule out coming back to Scandinavia, to Copenhagen at some point,” expresses Maria.

Any tips or advice for future Ph.D. students?

“This is a tough question; I think that this is so dependent on the person. In speaking with friends doing their PhD, I realize we each have different needs, so the Ph.D. process is about finding what works best for you. If you are more of an independent person and you want to do more of your own thing, it is good to know that you will be getting that space from your supervisor. However, if you are someone who needs a little more guidance, then it is also good to know that from the beginning.

I also want to stress the importance of maintaining a good work-life balance. This is something that I have personally struggled with, and I think maintaining a good balance is the only way to avoid burning out. My advice, as cliche as it may sound, is to make sure that you fill up the days with things that make you happy and just try to balance it out. I also think going to conferences is something I highly recommend, as it is something that really helped me. I was lucky enough to go to both national and international conferences, which really helped when the motivation was low to bring me back up. Just seeing all the exciting things that are going on in your field and the fact that there is always more to be done, really helps to bring you to the next step.

Lastly, I feel like the exact content of your Ph.D. does not matter too much in the end. If you are interested in the general topic, I would mainly focus on finding a good match with the supervisor and an overall supportive research environment. Is it a healthy workplace to work in?

Of course, this is hard to know right away, so it’s important to ask questions related to this when interviewing. Remember you are being interviewed to determine whether you are a good fit for the role, but you should also be interviewing them as to whether this research group, this workplace, their leadership style, is a good fit for you as well,” concludes Maria.