Desmoid tumors are rare, locally aggressive neoplasms with unpredictable behavior. Although some tumors are indolent, resolving spontaneously, with tamoxifen, or with anti-inflammatory medications, others are prone to local recurrence, leading to significant morbidity, impaired function and poor quality of life for patients. For patients with advanced, refractory tumors, intensive chemotherapy regimens such as methotrexate/vinblastine or doxorubicin/dacarbazine can produce significant radiographic responses and symptomatic improvement. However these therapies are associated with both short and long-term toxicities. The ability to personalize therapy based on a predictive marker from an individual patient’s tumor would allow early treatment of aggressive tumors with chemotherapy, while sparing patients with indolent tumors or those more likely to respond to milder interventions. Recently, desmoid tumors with particular mutations in CTNNB1, including S45F, have been shown to have a higher risk of recurrence. Additionally, desmoid tumors with S45F mutations were less likely to respond to conservative treatments with imatinib or meloxicam. However, it is unknown whether S45F mutated tumors are more likely to respond to chemotherapy. In this proposal, we will obtain tissue and radiographic imaging for our existing database of desmoid tumor patients, and perform CTNNB1 sequencing to identify specific mutations. Through a collaboration with MD Anderson Cancer Center, our combined datasets will then be analyzed to determine whether the presence of S45F mutations correlates with MRI response to various chemotherapy regimens. The ability to use CTNNB1 mutation status to predict behavior of desmoid tumors and to guide therapeutic decisions would have immediate implications for clinical management of these rare yet often aggressive tumors.

LAY VERSION OF ABSTRACT- Correlation of CTNNB1 mutation status with chemotherapy response by MRI in patients with desmoid tumors

This project aims to provide a fast, semi-high throughput and cheap animal model for identifying and/or characterizing promising drug targets for treating desmoid tumors. In addition the platform allows pre-clinical assessment of novel candidate therapeutic compounds. The project builds on the recent introduction of efficient genome editing methods using TALEN and CRISPR/Cas9, which are creating unique and unmatched opportunities in several research fields, including cancer research. For the first time it is now possible to create functional gene knockouts in a number of model organisms. We have recently generated the first genetic tumor model in the organism Xenopus tropicalis. Because of the external development of the Xenopus embryo and its diploid genome, gene targeting experiments using CRISPR/Cas9 or TALEN are extremely efficient and cheap. Interestingly, when locally targeting the tumor suppressor gene APC we generated tadpoles that rapidly (< 1.5 months) and efficiently (>90%) developed desmoid tumors. This model presents a unique and novel experimental platform that (i) allows the rapid screening and evaluation of genes that contribute to the growth of the tumor, (ii) could serve to assess the clinical relevance of novel drug targets for treating desmoid tumors and (iii) can be used as a preclinical drug screening/assessment. We believe that our model offers a unique experimental platform that can be easily plugged into the research lines of several groups active in the field.

LAY VERSION OF ABSTRACT- Identifying targets for therapy in a novel genetic Xenopus model for desmoid tumor formation

Desmoid tumors (DTs) are rare mesenchymal lesions with a high rate of local recurrence. Their common feature is a deregulated WNT pathway, mainly caused by gain-of-function mutations in exon 3 of the CTNNB1 gene (encoding for beta-catenin), resulting in nuclear accumulation of beta-catenin. Even though it is controversial, several studies have shown that the mutation S45F strongly correlates with increased propensity for desmoid recurrence as compared to T41A mutation. Therefore, it is important to investigate the differences between these 2 genetic alterations in order to identify potential targes for novel molecular therapies. In studies conducted within the premise of our previously funded DTRF seed grant, we were able to establish a desmoid tissue and cell strain repository. Furthermore, we showed that the difference between the CTNNB1 T41A and S45F mutations is not due to differential protein expression levels, since beta-catenin is equally expressed in both mutations. Our gene array analysis showed that pro-apoptotic genes are downregulated and anti-apoptotic genes are upregulated in the cells with the S45F mutation when compared to the T41A mutation. Moreover, we showed that there is no significant induction of apoptosis in the S45F mutated desmoid cell strains when compared to the T41A mutated cells. Interestingly, the impairment of apoptosis appears to be specific to the CTNNB1 S45F mutation and not to desmoid tumors per se. Interim results are not promising, confirming our initial observation. However, these findings are in need of further investigation to identify the molecular mechanisms driving the differences in the induction of apoptosis between the T41A and S45F mutated tumors. Once we understand these differences, these findings may potentially have an impact on patients in the clinic. Finally, we have also started evaluating the effects of agents commonly used for the treatment of DT such as Sorafenib and Imatinib, as potential alternative therapies for patients harboring the beta-catenin S45F mutation. In the second year, we propose to: 1) continue establishing and characterizing human desmoid tumor cell strains, creating a desmoid tumor tissue repository in our new institution as well as to continue trying to establish a desmoid tumor mice model; 2) unravel the molecular mechanism behind the differences in the induction of apoptosis between the CTNNB1 T41A and S45F mutation, and 3) evaluate the efficacy of other therapies for patients harboring the beta-catenin S45F mutation, such as Sorafenib and Imatinib.

LAY VERSION OF ABSTRACT- Reactivation of apoptosis: a potential therapeutic target for desmoid tumors with CTNNB1 S45F mutation

Desmoid tumors (DT) are locally invasive soft tissue growths with no directed therapies currently. While two genes (β-catenin and adenomatous polyposis coli) have been found in patients who develop desmoids, it is unclear how these mutations and other downstream mechanisms lead to desmoid tumorigenesis. Extensive research has been explored in the molecular biology of desmoids; however, the use of metabolomics to understand the how the low molecular weight complements of cells, tissues, and biological fluids are perturbed by this highly localized disease. Additionally, the Desmoid Collaboration for a Cure has identified 45 active drugs against primary cell lines. It is unclear how these therapies perturb the metabolome, outside the Wnt and notch pathways. This proposal will use broad spectrum metabolomics to study the tumorigenesis process of fibroblasts to desmoids by investigating paired desmoid and fibroblast cell lines, in addition to unaffected fibroblast cells. Additionally, this proposal will explore the effects of three of the active drugs identified by Collaboration for a Cure on the desmoid and fibroblast cells. It is our hope that this research project will provide knowledge to understand more about the biochemistry of desmoid formation from normal tissue, and how these drugs will help fight desmoid tumors.

LAY VERSION OF ABSTRACT- A metabolomics pilot study on desmoid tumors and novel drug candidates

Aims: To define the natural history and outcomes of patients with desmoid tumors, a rare, locally invasive soft tissue tumor. Methods: Collaborate with Fu Jen University, Taiwan to use a record linkage approach with the Taiwan National Health Insurance Research Data Base (NHIRD) that contains clinical information on 23 million people. Use ICD 10 codes and key words to pull pathology records for review; review 100 records or more to develop an algorithm to ensure specificity; mine the data and develop steps for descriptive epidemiology. Innovation: Data generated from this project will further the understanding of the disease course, impact of available interventions, and the burden of the disease for an individual patient and society as a whole. It will inform the design of future clinical trials for therapeutic interventions in patients with desmoid and could lead to the development of a new treatment for a disease for which there is currently no US Food and Drug Administration (FDA) approved systemic treatment. The pilot project could become the prototype of studying rare diseases using Big Data.

LAY VERSION OF ABSTRACT- Desmoid Tumors for Big Data Linkage