Periodic Reporting for period 1 - PROS-VARIANT (PIK3CA-Related Overgrowth Spectrum: molecular mechanisms and preclinical modelling of PIK3CA VARIANTs)
Période du rapport: 2022-09-01 au 2024-08-31
The PIK3CA-related overgrowth spectrum (PROS) includes a group of rare congenital disorders that result in abnormal tissue growth in various parts of the body, such as the vasculature, fat, muscle, bone, brain, and skin. Patients with PROS can have a wide range of clinical manifestations depending on which tissues are affected; some may present as complex syndromes, while others may have isolated lesions like vascular malformations.
These disorders arise from somatic mutations in the PIK3CA gene that occur during early development. The PIK3CA gene encodes the p110a protein (PI3Ka), a catalytic isoform of the PI3K responsible for generating the lipid PIP3 which serves as second messenger. The PI3Ka signaling pathway regulates essential cellular processes such as growth, survival, proliferation, and migration. In disease contexts, activating mutations in PIK3CA can occur throughout the entire gene leading to the overactivation of this signaling pathway.
Individuals with PROS often face serious complications and life-threatening conditions, which require extensive surgeries and treatments like pulsed laser therapy and sclerotherapy. However, current treatments are frequently insufficient, leading to high rates of recurrence and worsening symptoms. Recently, the FDA approved alpelisib, a targeted medication for treating PROS, which has reduced tissue growth and pain in some patients; however, ohters do not respond well or experience significant side effects, causing them to stop treatment. This highlights the urgent need for a deeper understanding of the specific biological pathways involved in PROS, which can help improve patient care and lead to the development of more effective therapies that minimize side effects. Since PROS primarily affects children, better insight could allow for earlier interventions, reducing complications and improving long-term health outcomes.
The main goals of our project were to gain insights into the physiological and molecular aspects of PROS by exploring key questions about when (the timing of mutation acquisition), where (the specific cell types involved), which (the types of PIK3CA mutation), and how (the mechanisms triggered by these mutations) these factors contributed to the development and severity of PROS. Our specific objectives included: (1) identifying the molecular and cellular changes caused by strong (H1047R) and weak (E726K) PIK3CA mutations and (2) studying how PROS develops over time and in different tissues using new mouse models.
These disorders arise from somatic mutations in the PIK3CA gene that occur during early development. The PIK3CA gene encodes the p110a protein (PI3Ka), a catalytic isoform of the PI3K responsible for generating the lipid PIP3 which serves as second messenger. The PI3Ka signaling pathway regulates essential cellular processes such as growth, survival, proliferation, and migration. In disease contexts, activating mutations in PIK3CA can occur throughout the entire gene leading to the overactivation of this signaling pathway.
Individuals with PROS often face serious complications and life-threatening conditions, which require extensive surgeries and treatments like pulsed laser therapy and sclerotherapy. However, current treatments are frequently insufficient, leading to high rates of recurrence and worsening symptoms. Recently, the FDA approved alpelisib, a targeted medication for treating PROS, which has reduced tissue growth and pain in some patients; however, ohters do not respond well or experience significant side effects, causing them to stop treatment. This highlights the urgent need for a deeper understanding of the specific biological pathways involved in PROS, which can help improve patient care and lead to the development of more effective therapies that minimize side effects. Since PROS primarily affects children, better insight could allow for earlier interventions, reducing complications and improving long-term health outcomes.
The main goals of our project were to gain insights into the physiological and molecular aspects of PROS by exploring key questions about when (the timing of mutation acquisition), where (the specific cell types involved), which (the types of PIK3CA mutation), and how (the mechanisms triggered by these mutations) these factors contributed to the development and severity of PROS. Our specific objectives included: (1) identifying the molecular and cellular changes caused by strong (H1047R) and weak (E726K) PIK3CA mutations and (2) studying how PROS develops over time and in different tissues using new mouse models.
Our goal has been to understand the physiological and molecular aspects of PROS by investigating various factors that we hypothesize play a role in the onset and severity of PROS, including the type of PIK3CA mutation, the timing of mutation acquisition, and the specific cell type that first acquires the mutation.
For our first objective, we focused on understanding how different PIK3CA mutations, specifically H1047R, E545K, and E726K, affect endothelial cells at the molecular level. Endothelial cells line the blood vessels, and they are commonly affected in PROS. We achieved this by isolating and analyzing these cells from special mouse models and patients. We observed that these mutations activated signaling pathways, like the PI3K and MAPK pathways, in distinct ways, and that they responded differently to various stimuli. RNA sequencing provided a transcriptomic profile for each mutation, revealing distinct deregulated biological pathways and enhancing our understanding of variant-specific contributions to disease pathogenesis.
For our second objective, we began modeling and exploring how PROS developed over time and in different tissues by comparing the strong mutations (H1047R and E545K) with the weaker variant (E726K) using specially modified mouse models. We found significant differences in embryonic survival and blood vessel development. Also, expressing these mutations at different developmental stages led to different phenotypes, emphasizing how both timing and type of mutation could influence the overall disease outcome. We also used an ear skin model to investigate the impact of PIK3CA mutations on lymphatic overgrowth. Our findings showed that the H1047R, E545K, and E726K mutations display distinct pathogenic profiles across multiple in vivo models of PROS, influencing embryonic development, vascular integrity, and tissue-specific overgrowth in unique ways.
In summary, our results have shown that different PIK3CA variants have unique characteristics that shape their contribution to the disease.
We have shared our findings at scientific conferences and workshops, reaching academic communities, clinicians, and patients. A significant achievement was launching the Emerging Leaders in Biomedicine symposium series in Barcelona, fostering collaboration among early-career biomedical researchers. This project has also fostered partnerships with pharmaceutical companies, and we are actively working to publish our studies in open-access journals and repositories to make our findings widely available. Overall, the knowledge gained from this research enhances our understanding of PI3K signaling and sets the stage for future treatments to improve the lives of those affected by PROS.
For our first objective, we focused on understanding how different PIK3CA mutations, specifically H1047R, E545K, and E726K, affect endothelial cells at the molecular level. Endothelial cells line the blood vessels, and they are commonly affected in PROS. We achieved this by isolating and analyzing these cells from special mouse models and patients. We observed that these mutations activated signaling pathways, like the PI3K and MAPK pathways, in distinct ways, and that they responded differently to various stimuli. RNA sequencing provided a transcriptomic profile for each mutation, revealing distinct deregulated biological pathways and enhancing our understanding of variant-specific contributions to disease pathogenesis.
For our second objective, we began modeling and exploring how PROS developed over time and in different tissues by comparing the strong mutations (H1047R and E545K) with the weaker variant (E726K) using specially modified mouse models. We found significant differences in embryonic survival and blood vessel development. Also, expressing these mutations at different developmental stages led to different phenotypes, emphasizing how both timing and type of mutation could influence the overall disease outcome. We also used an ear skin model to investigate the impact of PIK3CA mutations on lymphatic overgrowth. Our findings showed that the H1047R, E545K, and E726K mutations display distinct pathogenic profiles across multiple in vivo models of PROS, influencing embryonic development, vascular integrity, and tissue-specific overgrowth in unique ways.
In summary, our results have shown that different PIK3CA variants have unique characteristics that shape their contribution to the disease.
We have shared our findings at scientific conferences and workshops, reaching academic communities, clinicians, and patients. A significant achievement was launching the Emerging Leaders in Biomedicine symposium series in Barcelona, fostering collaboration among early-career biomedical researchers. This project has also fostered partnerships with pharmaceutical companies, and we are actively working to publish our studies in open-access journals and repositories to make our findings widely available. Overall, the knowledge gained from this research enhances our understanding of PI3K signaling and sets the stage for future treatments to improve the lives of those affected by PROS.
This project was conceived to make significant advancements in our understanding of the PROS, filling critical gaps in knowledge regarding its causes and biology. By focusing on the specific effects of different PIK3CA mutations, we aimed to refine our understanding of how this disease develops and identify potential treatment targets. We have developed a range of PROS models essential for testing new treatment strategies in the future, as well as more complex mouse models to trace mutant cells. This will help us answer important questions about why certain tissues, like the vasculature, are more prone to overgrowth than others. These insights will help clarify the tissue bias seen in PROS patients and improve our understanding of resistance mechanisms. Moreover, these models will also have significant implications for cancer research and aging, as these mutations are commonly found in those areas as well.
From a socio-economic standpoint, our findings could have a substantial impact. A better understanding and treatment of PROS could reduce healthcare costs and improve the quality of life for those affected. The social implications of this research extend beyond PROS, as PIK3CA mutations are also implicated in cancer and aging.
On a personal note, this project has truly changed how I approach research. I’ve gained a deeper understanding of genetic pathways and how cells behave over time, and I've improved my skills in designing innovative experimental models to tackle the new challenges that come up during research. Working directly with clinicians and patients to understand their needs has been especially exciting and rewarding. This experience has led to valuable collaborations with other researchers and clinicians, crucial not only for the success of the project but also for my future career. This journey has fueled my enthusiasm for this research area and inspires the next steps in my career. I’m confident this project has been pivotal in my path to becoming an independent researcher, and I’m excited about the potential outcomes that will deepen our understanding of the PI3K field and congenital disorders, opening new opportunities for exploration.
From a socio-economic standpoint, our findings could have a substantial impact. A better understanding and treatment of PROS could reduce healthcare costs and improve the quality of life for those affected. The social implications of this research extend beyond PROS, as PIK3CA mutations are also implicated in cancer and aging.
On a personal note, this project has truly changed how I approach research. I’ve gained a deeper understanding of genetic pathways and how cells behave over time, and I've improved my skills in designing innovative experimental models to tackle the new challenges that come up during research. Working directly with clinicians and patients to understand their needs has been especially exciting and rewarding. This experience has led to valuable collaborations with other researchers and clinicians, crucial not only for the success of the project but also for my future career. This journey has fueled my enthusiasm for this research area and inspires the next steps in my career. I’m confident this project has been pivotal in my path to becoming an independent researcher, and I’m excited about the potential outcomes that will deepen our understanding of the PI3K field and congenital disorders, opening new opportunities for exploration.