Descripción del proyecto
Overgrowth syndromes (OS) are rare genetic disorders that can be either localized or generalized. In most cases, the mutations are not inherited but occur during embryogenesis leading to somatic mosaicism. The genes involved in OS are not well characterized but most appear to be part of the PIK3CA/AKT/mTOR pathway, a major actor in cell growth and proliferation. Among the different genes, gain-of-function mutations of PIK3CA have a prominent role. Patients with PIK3CA gain of function mutation (PROS) usually have complex tissue malformations, including abnormal vessels, anarchic adipose tissue, muscle hypertrophy and/or bone deformation. Currently, there are no specific treatments for PROS patients. Patients mainly receive supportive care including debulking surgery, sclerotherapy and nutritional support. PROS often result in severe disabilities with deleterious social consequences and premature death. We recently generated a mouse model of PROS that, for the 1st time, recapitulates the patient phenotype, identified BYL719, a PIK3CA inhibitor undergoing development in oncology, as a potential therapeutic for PROS and demonstrated the efficacy of this drug in our mouse model (Venot et al, Nature 2018). Based on these very promising results, we were authorized to treat adults and children suffering from very severe forms of PROS. The clinical outcome is very promising. Now, in this project, we will decipher the physiopathology of PROS, identify biomarkers and new treatments. To this aim, we will combine in vitro and in vivo approaches using very innovative technologies and new mouse models of OS. Consistently with my previous works, we will extend our findings to Human through our unique PROS Biobank. The accomplishment of this project may lead to the discovery of novel therapeutic targets and strategies to slow down the progression of PROS. But, more importantly, based on the pleiotropic role by PI3KCA in cancer, our findings will open new perspectives in oncology.