Year: 2025
PI Name: Lotte E.R. Kleimeier
Mentor Name: Rick Greupink
Project Title: Optimizing Targeted Therapy in RASopathy Patients with Syndromic Central Conducting Lymphatic Anomalies
Abstract: Central Conducting Lymphatic Anomalies (CCLA) involve functional defects of the central lymphatic system that impair lymphatic drainage. Conventional therapies focus on symptomatic relief, rather than the probable pathophysiology, leaving patients refractory and at risk of poor outcomes or death. Molecular targeted treatment have shown promising results, but the absence of structured drug development, including dose optimization, and prospective trials, limits evidence-based therapies. We hypothesize that integrating physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) modeling with exploratory clinical data will advance our understanding of dose–response relationships in CCLA. By uniting in vitro, in silico, and in vivo methods, this innovative approach is designed to directly inform precise, age-appropriate dosing of targeted therapies and address a critical unmet need.
The specific aims are: 1) To describe the pharmacokinetics of MEK-inhibitors via PBPK/PD modelling, incorporating specific anatomical and physiological data of the target populations (physiology models), as well as physicochemical and in vitro pharmacological properties of drug candidates (compound models). 2) To establish dose–concentration–effect relationships for targeted therapies in CCLA by collecting exploratory observational PK and PD data from off-label treated patients at our academic medical center. 3) To use the developed model and dose–concentration–effect relationships to define clinically relevant drug dosing regimens across age groups, from neonates to adults, with CCLA.
Our approach leverages existing physiology models, in silico PBPK/PD simulations, and real-world clinical data from CCLA patients. This work initiates the foundation for rational, individualized drug dosing strategies and support future clinical trials in this underserved patient population.
Funding from the Lymphatic Malformation Institute, LGDA, and LGD Alliance-Belgium
Year: 2025
PI Name: Svatava Merkle
Mentor Name: Timothy D. Le Cras
Project Title: Targeted Therapies for Kaposiform Lymphangiomatosis
Abstract: Kaposiform lymphangiomatosis (KLA) is a life-threatening vascular anomaly that affects
children and young adults. KLA is characterized by abnormal growth of lymphatic vessels
in the chest and other organs leading to fluid buildup, breathing problems, bleeding, and
significantly shortened life expectancy. Current treatments, including the drug sirolimus,
can help slow the disease but often fail to stop it or produce lasting improvement. A major
discovery was that most patients with KLA have a mutation in a gene called NRAS, which
causes two important cellular growth pathways—the PI3K and MAPK pathways—to
become overly active. These pathways mediate cell growth and survival, but when
constantly activated, they can drive uncontrolled growth as seen in cancers with this gene
NRAS mutation and in patients with KLA. Our research group has developed a human
cell culture model that mimics KLA and shows the same mutation and disease behavior.
In this project, we will test whether a newer drug, alpelisib (which blocks the PI3K
pathway), works better than the standard therapy sirolimus. We will also test a
combination approach that blocks both the PI3K and MAPK pathways, using drugs that
are already FDA-approved for cancer treatment. Our goal is to find more effective and
less toxic treatments for patients with KLA. The proposed project will generate important
preclinical data and lay the foundation for future clinical trials, with the hope of offering
patients better outcomes and improved quality of life.
Funding from the Lymphatic Malformation Institute, LGDA, and LGD Alliance-Belgium
Year: 2024
PI Name: Nils Rouven Hansmeier
Mentor Name: René Haegerling
Project Title: Spatial Distribution of PIK3CA-mutated Cells in Lymphatic Malformations
Abstract: Lymphatic malformations are clinically very heterogeneous ranging from small local ‘birthmarks’ to life-threatening entities affecting entire limbs, organs or larger parts of the human body. Often, these conditions require surgical and/or pharmacological intervention to prevent further disease progression and to increase patients’ quality of life. Therefore, an in-depth understanding of the underlying vascular pathology is crucial for appropriate treatment and management. However, our current knowledge on lymphatic malformations and in particular spatial cellular distribution of individual mutated and non-mutated cells within the lesion is very limited. This is due to insufficient tools and technologies to visualize and investigate individual cells at a spatial multicellular level. To overcome these limitations and gaps of knowledge, the proposed project aims to generate novel state-of-the-art nanobody-based reagents suitable for immunofluorescence staining of entire tissue biopsies and combine this with cutting-edge imaging and visualization technologies using lightsheet microscopy. Nanobodies raised against wildtype and mutated PIK3CA, i.e the most frequent cause for somatic lymphatic malformations, will be used to visualize the spatial distribution of individual cells and its expression of wildtype and mutated protein in diseased tissue samples using optical sectioning. This will allow a spatial clonal analysis in lymphatic malformations positive for PIK3CA mutation. In summary, the proposed project represents an innovative approach that has the great potential to provide for the very first time novel insights into spatial cellular arrangement of somatic PIK3CA mosaicism and to allow spatial phenotyping as well as clonal analysis in patients with PIK3CA-associated lymphatic malformations.
Funding from the LGD Alliance Europe.
Year: 2024
PI Name: Yarelis Gonzalez-Vargas
Mentor Name: Brandon Dixon
Project Title: Towards a Precision Medicine Approach for the Study and Management of Pediatric Lymphatic Malformations
Abstract: This project aims to develop a high-throughput testing platform for lymphatic malformations (LMs), a rare type of vascular anomaly caused by genetic mutations. Our goal is to create a patient-specific Micro-Physiological System (pMPS) using advanced biomaterials and artificial intelligence (AI) to enhance pre-clinical drug testing. Current treatments for LMs, often repurposed from cancer therapies, are not well-tolerated by children. By using patient-derived organoids (PDOs) embedded in a specially designed hydrogel, we can replicate LM conditions in vitro. These PDOs will be used to test drug responses, with data collected to train a deep learning model that automates image analysis and reduces human error. This innovative approach leverages the combined expertise of bioengineering and medical genetics, aiming to streamline the development of effective and safer treatments for pediatric patients with LMs. The project not only seeks to improve drug efficacy predictions but also to advance understanding of LM biology, potentially leading to better therapeutic strategies.
Funding from the Lymphatic Malformation Institute
Year: 2024
PI Name: C. Griffin McDaniel
Mentor Name: Tim Le Cras
Project Title: Mutant to wild-type endothelial cell interactions in the pathogenesis of kaposiform lymphangiomatosis
Abstract: Kaposiform lymphangiomatosis (KLA) is a complex lymphatic anomaly (CLA) that can cause fluid leakage around the heart and lungs and severe bleeding problems. A mutation in NRAS, an important gene for cell growth and survival, has been found in affected tissue from patients with KLA. This mutation has also been identified in many cancers. However, only a small percentage of the cells within the diseased tissues of KLA patients have the NRAS mutation. Furthermore, bleeding problems in KLA patients are unexpected as the lymphatic system does not normally transport blood. We hypothesize that the NRAS mutant cells in KLA communicate with surrounding normal cells to drive abnormal vessel growth and contribute to disease pathogenesis. To address this hypothesis, we will use human cells cultured in petri dishes and mouse models. First, we will mix mutant and normal human cells and determine the proportion of mutant cells that is required to cause abnormal vessel structures in a three-dimensional cell culture model of vessel formation. Then, mutant and normal cells will be mixed and implanted into mice to determine the proportion of mutant cells needed to cause abnormal vessel growth in vivo. Finally, we will culture normal and mutant cells on nearby beads and determine whether the mutant cells secrete factors that cause the normal cells to contribute to abnormal vessel growth. The goal of these studies is to improve our understanding of the disease process in KLA patients, gain insights into other CLA, and identify new therapeutic targets.
Funding from LGDA.
Year: 2023
PI Name: Nour C. Bacha
Mentor Name: Carrie Shawber
Project Title: Assessment of Lysosomal Dysfunction in Lymphatic Anomaly Pathogenesis
Abstract: Lymphatic anomalies are congenital slow-flow diseases, including Generalized Lymphatic Anomalies (GLA). Genetic studies have shown that somatic mutations leading to PI3K/AKT/mTOR and/or RAS/MAPK pathway hyperactivation are causal to GLA pathogenesis. Due to crosstalk between the RAS and PI3K pathways, most mutations in GLA lead to AKT and mTOR hyperactivation. Our team’s preliminary data revealed that hyperactivation of PI3K signaling led to the abnormal cytoplasmic accumulation of CD31 and VE-CADHERIN in lymphatic anomaly patient-derived lymphatic endothelial cells (LA-LECs) with PIK3CA variants or variants leading to RAS hyperactivation compared to control cells. This correlated with reduced expression of two essential proteins at the cell surface, CD31 and VE-CADHERIN, and an increase of CD31 in endosomes and lysosomes of LA-LECs. As PI3K/AKT/mTOR signaling inhibits lysosomal degradation, these data suggest that LA-LECs have lysosomal insufficiency downstream of PI3K/mTOR hyperactivation that contributes to GLA pathogenesis. We hypothesize that hyperactivation of PI3K signaling leads to lysosomal dysfunction in LA-LECs that contributes to their pathogenesis and can be reversed by improving lysosomal protein degradation. Therefore, we propose to assess CD31 and VE-CADHERIN degradation and expression related to lysosomal dysfunction and to inhibit mTOR signaling pathway to evaluate this dysfunction downstream PIK3CA hyperactivation. We will also use drugs to improve lysosomal degradation and determine if they normalize CD31 and VE-CADHERIN expression at the cell surface which is crucial for lymphatic vasculature structure integrity.
Funding from LGDA.