25 Interviews for the FNP?s 25th Anniversary. The Foundation for Polish Science (FNP) celebrates its 25th anniversary this year. To mark the occasion, we have invited 25 beneficiaries of our programmes to tell us about how they ?practise? science. What fascinates them? What is so exciting, compelling and important in their particular field that they have decided to devote a major part of their lives to it? How does one achieve success?
The interviewees are researchers representing many very different fields, at different stages of their scientific careers, with diverse experience. But they have one thing in common: they practise science of the highest world standard, they have impressive achievements to their credit and different kinds of FNP support in their extensive CVs. We are launching the publication of our cycle; successive interviews will appear regularly on the FNP website.
Pleasant reading!
A never-ending story
An interview with Halina Waś PhD, cellular biology researcher, by Patrycja Dołowy.
PATRYCJA DOŁOWY: So what?s the story with old cancer cells?
HALINA WAŚ: Maybe I?ll start by saying that my first postdoctoral fellowship was at the Nencki Institute of Experimental Biology in Warsaw, in Prof. Ewa Sikora?s team examining the molecular basis of cellular senescence. Initially I was involved in a project involving signalling pathways, which may be essential for this process. It was during this research that I learned of the atypical division of senescent cancer cells. There is a basic dogma in the field that senescent cells do not divide. Ten years ago Prof. Rengaswami Rajamaran and his team proposed that senescent cancer cells might divide, but in an atypical way which they called ?neosis.? Not into two daughter cells, as in mitosis, or four, as in meiosis, but more, even a dozen daughter cells. That totally fascinated me! Rajamaran also suggested that the daughter cells may display (at least initially) the characteristics of cancer stem cells. The topic of cancer stem cells had interested me when I was working on my doctorate. I decided to delve into this incredible mechanism.
And that was the beginning of your research on senescent cancer cells?
Yes, but I needed funding. That is one of the valuable lessons I took from my teachers, Prof. Alicja Józkowicz and Prof. Józef Dulak, during the work on my doctorate: if you want to conduct research, you have to actively seek funding. Good science costs money. So I filed two grant applications, one to the Ministry of Science and Higher Education (for the Iuventus Plus programme) and the other to the Foundation for Polish Science (for the INTER programme). I managed to get money from both sources. These funds afforded me scientific independence: conducting research according to my own ideas, paying a salary to my co-workers, buying reagents and animals. Thanks to the support from the ministry and FNP (in this case funds not only to realize the project, but also a stipend portion for me), I could concentrate exclusively on science, and that was great. One of the main assumptions of FNP?s INTER project was interdisciplinary cooperation. That was a huge challenge! Mainly because scientists from different fields speak different languages and sometimes it is hard for them to understand one another. I carried out projects in the lab of Prof. Bożena Kamińska at the Nencki Institute. Looking back, I can say that this was a very important experience for me, thanks to which I learned autonomy and lots of new things: from conducting research, establishing and pursuing cooperation, to organizational issues connected with project management. It also deepened my conviction that I must never give up, but pursue my own work. Even if some people don?t accept it or understand it. True science and hard work always speak for themselves!
I remember your show during the INTER competition. You did a great job of sharing knowledge with the audience.
Thanks. The finals were preceded by training in how to make public appearances. That was very inspiring for me. I switched the concept of my competition presentation by 180 degrees. During the trial presentation, when I discussed my research I could tell from the faces of my colleagues that they didn?t understand much of it. My presentation was too complicated, too crammed with details, and highly abstract. The facilitator, Mirek Oczkoś, told us that when preparing a presentation we have to answer three questions: What do we want to say? Who is the audience? How do we want to convey this? Finally, we should refer to something people know, something they associate with their own life. I wanted to talk about mechanisms occurring in cancer cells in response to chemotherapy. First, that cancer cells can undergo senescence in that situation and divide unusually. Second, what consequences this can have for the patient. So it dawned on me: senescent cancer cell?good or bad? So a court! I took on the role of a judge summing up the closing arguments of the accuser and the accused. My co-worker Joanna Czarnecka played the role of a senescent cancer cell accused of causing recurrence of cancer after therapy in oncology patients. Because the evidence was unpersuasive, I let the cell go free.
Is there any new evidence for the court?
Yes, definitely. Our research, conducted in cooperation with scientists from the Nencki Institute, particularly Joanna Czarnecka and Kamila Barszcz, is casting new light on this issue. First, we now know which chemotherapeutic agents cause senescence of colon cancer cells and which do not. Under conditions of in vitro cell cultures, we tested three drugs that are given to patients in the clinic, and we found that the cellular response to each drug was different. Interestingly, when the drugs were withdrawn, some of these senescent cancer cells began to divide, but with a long delay. I think that cellular senescence may be one of the mechanisms responsible for relapse after completion of treatment. I imagine that a senescent cancer cell is something like a spore which is inactive for a long time, during and after treatment, but under favourable conditions starts dividing again, and the cancer revives.
Dr Halina Waś, photo by One HD
So guilty after all?
I asked myself whether we can somehow arrest the division of senescent cancer cells. I thought about autophagy. This is a very important cellular process. Under conditions of stress, caused for example by starvation or toxins, the cell consumes itself. This removes damaged macromolecules and cellular organelles. Very unfavourable conditions prevail in a malignant tumour. There?s a shortage of nutritive substances. There?s overcrowding. There?s a lack of oxygen. The cancer cells divide very quickly and exhaust all the reserves. We cause additional stress when we administer radiotherapy or chemotherapy. Autophagy is one of the processes that enable a cancer cell (particularly a senescent one) to manage in this chaos. To block autophagy we applied a chemical substance that arrest this process, known as an inhibitor.
Did it work?
In the first few days after administering it, the cancer cells suffered a serious blow, and many of them died. But later those that survived quickly restored the population. We were most surprised by the result of the experiments on animals. Tumours grew faster if we gave the mice senescent cancer cells where we had arrested the autophagy! Now we are trying to figure out why that happened. Clinical research is currently underway trying to enhance the effectiveness of chemotherapy with the help of autophagy inhibitors. Our research could lead to a description of the molecular mechanisms occurring during such therapy?whether beneficial or detrimental to the patient. It must be remembered that for the patient, chemotherapy is toxic. It impacts not only cancer cells, but also normal cells dividing in the organism: blood cells, epithelial tissue in the gastrointestinal tract and the skin. Patients suffer health-threatening and life-threatening side effects, including lowered immunity. The smallest infection in a patient undergoing chemo can end very badly. This is why the situation sometimes reaches a stalemate: either the cancer or the patient. It also sometimes happens that cancer retreats in response to therapy, but then after several months or years the patient suffers a recurrence of the disease. And often highly malignant. The research (including research by other teams around the world) suggests that senescence of cancer cells induced by chemotherapy may, paradoxically, be one of the mechanisms for developing resistance to chemotherapy.
What else induces senescence of cancer cells?
The stress factors damaging DNA, for example the chemical substances or radiation we apply during therapy. They induce so-called stress-induced premature senescence (SIPS). This is a sudden process, occurring within a few days. In response to DNA damage, a cell has three options. It can repair the damage and resume cell division. If the damage is extensive and threatens the integrity of the cell, then the cell is condemned to death. The third way is cellular senescence. Then the cell remains alive but does not replicate. At least in theory. The process of cellular senescence is very important for our bodies. It combats carcinogenic processes, halting replication of cells with defective DNA. If oncogens, i.e. genes fostering carcinogenesis, are activated in a healthy cell, that cell also undergoes senescence. Ultimately, if a cell breaks through all of these barriers and undergoes a carcinogenic transformation, by impacting it with DNA-damaging agents we can still induce its senescence. Just 10 years ago it was thought that cellular senescence can be a desired goal during therapy, since senescent cancer cells don?t replicate, and thus the disease in this form is controlled and will not spread.
But now you know that senescent cells can undergo these peculiar divisions?
That?s contrary to the dogma, right? Four years ago an article was published showing that the presence of senescent cancer cells in a tumour can increase patient mortality. Perhaps this is connected with these atypical divisions. At least that is what the in vitro studies suggest. This will have to be verified by applying very complex models. We still don?t know why some senescent cells divide. We can imagine that senescence is a process with stages and not just an end point. Perhaps at some stage a cell can turn from the path of senescence and begin to divide again. We still don?t know at which stage this switch occurs or what it looks like. Division of a senescent cell is a very rare phenomenon and hard to study. Capturing changes occurring at the level of individual cells is complicated in a culture?not to mention how difficult it will be to identify this under in vivo conditions, using animal models, and then in material derived from patients. We already know a lot about this topic, but still there are many unanswered questions. It can?t be ruled out that the results of these analyses will force us to update our definitions.
We?re still a long way from unlocking the secrets of cancer.
Yes. Sometimes I have the feeling that the deeper we delve into this topic, the less we know. There are so many things to examine. It is a complicated disease, multilayered and mercurial. This heterogeneity occurs not only between different types of cancer, but between tumours of the same type, and even within a single tumour in a single patient. All stressful situations?a shortage of nutrition and oxygen, the toxicity of therapy?cause cancer cells to evolve within the patient?s body. Only the best adapted survive. That?s why it is insufficient to administer one drug to kill all of the cells of a tumour. Currently therapies are being tested based on combining several drugs at once. For example, if we know that senescent cells can divide, it would be worthwhile to eliminate them or at least halt their division. Senescent cells are also dangerous because they produce various types of factors that can alter their environment. These factors affect other cancer cells, for example initiating their proliferation or spread to other organs. They can also induce the creation of blood vessels (angiogenesis), enabling growth of the original tumour as well as metastasis. Finally, factors produced by senescent cancer cells may affect the cells of the immune system. The cancer can reprogram those cells to work for its benefit rather than combating it.
Dr Halina Waś, photo by One HD
How did you become a cancer researcher?
I always wanted to do something important?something that could help other people. My mother had cancer when I was a child. Several years ago my sister also got sick. That certainly determined my choices and actions, and still does. I took up the study of biology at Jagiellonian University in Kraków. I completed my master?s and doctorate in the Department of Medical Biotechnology headed by Prof. Dulak. When my future academic adviser Prof. Józkowicz asked me what I was interested in, I said: cancer and the immune system. At that time no one in the department was involved in that. The main subject of research was angiogenesis and one of the antioxidant enzymes, heme oxygenase-1 (HO-1). But it was just at that time that we received a ?gift? from Prof. Stanisław Szala from Gliwice in the form of mouse melanoma cells. So Prof. Józkowicz proposed to me a project concerning the role of HO-1 in melanoma. That was it! I rolled up my sleeves and got to work. It turned out that an increased level of HO-1 in melanoma cells caused the cancers to develop better?they proliferated faster, were more resistant to stress and therapy, and had pro-angiogenic properties. We also conducted experiments on mice with a knocked-out HO-1 gene, to see how the level of HO-1 in healthy tissue influences the initiation of cancer. It was a model of chemical carcinogenesis in the skin of mice. If the mouse had a high level of heme oxygenase-1, tumours appeared later than in mice who had a lower level or lacked the enzyme. This suggested that the correct level of HO-1 in the skin had a protective effect on the mouse. But once a tumour had already formed, this enzyme caused faster growth of the cancer. In some of our research the driving force was accidental, or a seemingly minor observation, a detail.
For example?
One example is the role of sex hormones in the development of melanoma. Generally animal experiments are conducted on a single sex. But in the case of mice with a removed HO-1 gene, it was hard for us to obtain a large enough group of a single sex. So we decided to perform an experiment on both males and females. We then evaluated the presence of metastasis using bioimaging. A week after administering appropriately marked melanoma cells to the mice, we conducted the first scan. Tumours had begun to grow in all of the mice?s lungs. But by the second week and the third week, half of the mice did not have tumours. After a careful analysis it turned out that in the females the tumours had stopped growing, but in the males they continued to grow! We made additional in vitro tests. Indeed, the sex hormones influenced the growth of melanoma. This is confirmed in clinical data?mortality from melanoma is higher in men than in women.
Another situation. Melanoma cells produce a pigment?melanin?which is why they are dark. But when we introduced the HO-1 gene into these cells, the cells lost their colour. We drilled down into this issue. It turned out that this is connected to the degree of differentiation in the melanoma cells. This was the first step in studying the role of HO-1 in cancer stem cells.
It was similar when I decided to verify in my research model Prof. Rajamaran?s hypothesis that the daughter cells arising from division of senescent cancer cells can have the phenotype of stem cells. It turned out that it is mainly the senescent cells that have these characteristics! That observation became the basis for the Iuventus Plus grant application I filed with the Ministry of Science and Higher Education.
This is the coolest thing about science. New questions are always arising, and each discovery generates more questions. You have to observe and be mindful. And not be discouraged when the result is not what you expected. Then it?s the most interesting! You just have to follow it.
Why is it important to talk about all this?
The fundamental role of science is to investigate the world, seek truth. Scientists share knowledge by writing publications or travelling to conferences where they debate and form cooperation. But in the context of cancer?a topic so important to society?we should discuss our work more broadly, and reach everyone. I think this is our obligation. Practically everyone has somebody among their family or friends who has had cancer. It?s a disease that people fear. We are afraid of what we don?t understand. Here our role as scientists and doctors is to explain together to the society what cancer is, and the methods for diagnosing and treating it. I believe that this is knowledge that can save lives.
Two years ago, at the nationwide BIO2014 conference, Prof. Agnieszka Dobrzyń, Prof. Urszula Wojda and I, from the Nencki Institute, organized ?Science and Society? sessions. We invited winners of FNP?s INTER competitions from various years to cooperate. The lectures addressed topics related to biology, chemistry and physics. There was also a session about cancer. It was an open session anybody could attend. Dr Anna Wasik, Joanna Czarnecka and Kamila Barszcz assisted us in promoting the event at schools and universities of the third age. I remember the moment when we stood in front of the lecture hall wondering whether anybody was going to come. Then one of the biology teachers we had invited arrived, together with a large group of young people. It was moving.
You discuss science for the business community at Meet Biotech Boot Biotech, but you have also returned to Nowy Targ, to your old school, to talk to the students.
I think it?s important for science to reach a range of audiences. The connection between science and business is vital. The same with science and medicine. An excellent example is the initiative of Prof. Bożena Kamińska from the Nencki Institute, who is creating just such a platform, combining science, medicine and business to develop methods for diagnosing and treating brain tumours.
My lectures for the biology and chemistry classes at the high school were organized by my friend and former schoolmate Agnieszka Paprocka-Maciaś, in consultation with the head of the school. I discussed my research and scientific work. I wanted to show the young people that science is great and allows you to do interesting and important things. It doesn?t matter whether you?re from Warsaw, Kraków, or Nowy Targ.
What does science mean to you?
It?s my passion. I don?t even call it work. I like to discover, explore, wonder, experiment. And if anyone wants to take advantage of that, I?m happy to talk about it. Maria Skłodowska-Curie said that science is the only field where you can get paid to play and get dirty. There?s certainly some truth in that! But it?s also very responsible and difficult work that requires lots of determination and psychological toughness. ?Eureka!? moments don?t come every day. Day in and day out it can be tedious, abstract, and often without results. And you can?t switch off when you leave the lab. I?m constantly reading, seeking, checking new hypotheses. Just when it seems I?ve found the answer, new questions pop up. It?s a never-ending story.
What is lacking in the way we do science?
We don?t cooperate enough. And cooperation is necessary when taking on important and often risky research issues. Cooperation across different fields is vital. It opens up horizons. In the case of cancer, cooperation between researchers and doctors is obviously important. If we want to find a way to defeat cancer, we have to work together.
HALINA WAŚ, PhD works at the Nencki Institute of Experimental Biology of the Polish Academy of Sciences, in the Laboratory of Molecular Neurobiology. She is a two-time winner of stipends in the START programme (2008 and 2009) and a winner of the popularization of science programme INTER (2013).