The puzzle of malignancy in pluripotent stem cells
Pluripotent stem cells lie at the heart of many promising therapies in regenerative medicine and have potential for many different diseases, from diabetes to eye-diseases. But how do we ensure they are safe to use in patients? In his PhD project, Joaqu铆n Montilla Rojo dove into this question and developed an animal-free model to test the safety of pluripotent stem cells. His project was a collaboration between the veterinary sciences faculty at Utrecht 木瓜福利影视 (group prof. dr. Daniela Salvatori) and the Princess M谩xima Center for pediatric oncology ().
Why is this important?
鈥淭he pluripotent stem cell is a stem cell that can differentiate to any cell type in your body. That is also why these cells have great potential in regenerative medicine in many different diseases. However, when culturing these cells, they can change and become cancer-like. Which makes these cells not safe to use for therapies. My PhD focused on: Why does this transformation happen and how can we distinguish safe and unsafe cells in an animal-free way?鈥 Joaqu铆n explains.
鈥淧luripotent stem cells are in many ways very similar to cancer cells, but pluripotent stem cells have very tight control mechanisms that regulate them, and malignant cancer cells not. Right now, the only way to distinguish the two cell types is by using mice. If you inject the cells into mice, a tumor will form. If this tumor contains undifferentiated (cancer-like) cells in them, the cells that were injected are considered malignant and thus not safe to be used in a clinical setting.鈥 Joaqu铆n wanted to change this dependency on animals and developed a new model to test this malignancy.
Mimicking the mouse model
This new animal-free model uses the idea of so-called embryoid bodies. If you keep pluripotent stem cells in suspension and add all the nutrients that the cells might need, the cells spontaneously aggregate in 3D-spheres, the embryoid bodies. By modifying the culture conditions, he managed to improve the culture of these embryoid bodies. With these improvements, the new structures are able to show cancer-like features if the original pluripotent stem cells were malignant. The principle is really similar to the mouse model but without needing the mice. Comparing the new model to the traditional mouse model showed very promising results. 鈥淭he results were exactly the same as the existing mouse models, so we really showed that this new model is able to distinguish between safe and unsafe pluripotent stem cells.鈥
My project really required integrating knowledge from multiple disciplines
Focus on fully animal-free
The next step? Making the model fully animal-free. The new model still requires fetal bovine serum (FBS), an animal-derived product. But Joaqu铆n is not stopping at this point. He recently started as a postdoc in the Regenerative Medicine Center Utrecht (RMCU) and continues his project, aiming to make the new model completely animal-free.
Power of collaboration
鈥淢y project really required integrating knowledge from multiple disciplines,鈥 Joaqu铆n tells. 鈥淭his transformation from stem cells into cancer-like cells can also happen in the human body. When this happens in germ cells (egg and sperm cells), or derivatives thereof, this can develop into cancer in children and young adults. These cancers are investigated at the Princess M谩xima Center by the of prof. dr. Leendert Looijenga. The project benefits a lot from the gained knowledge about the molecular processes involved.鈥
Drivers of malignancy
Joaqu铆n鈥檚 research also uncovered genetic mechanisms that drive the malignant transformation of stem cells. These include chromosomal aberrations and TP53 mutations 鈥 features often seen in cancer cells. His research suggests similarities between malignancy in pluripotent stem cells and human cancers. Understanding these drivers could therefore not only improve stem cell quality control but also shed light on pediatric cancers and adult cancers, such as germ cell tumors.
Looking back
Joaqu铆n shares the importance of the collaborative culture at the RMCU, as well as at the Princess M谩xima Center. 鈥淗onestly, if it weren鈥檛 for the RMCU, I鈥檓 not sure I would have completed my PhD. The welcoming atmosphere and the constant collaboration made knowledge sharing easy, which was especially important since our group was just starting out.鈥 His advice for PhD students? 鈥淭he people around you are the most important. You will love and hate your project at the same time, but the people are the once鈥檚 that will help you persist in hard times.鈥