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Project

Impact of extracellular matrix organization in the tumor environment on efficacy of immunotherapy in DNA mismatch repair deficient tumors.

Immunotherapy is revolutionizing the clinical management of multiple cancer types including DNA mismatch repair-deficient tumors (Galluzi et al., 2018). However, even in this preselected group of patients, good and complete response are achieved in only one fifth of the patients (Le et al., 2016; Le et al., 2017). Thus, there are still enormous opportunities for improvement. The presence of an immunosuppressive tumor environment may be key to further optimization of immunotherapy (Jiang et al., 2016). Extracellular matrix accumulation and rigidity, and neo-expression of matrix proteins may be involved in T cell exclusion from the proximity of cancer cells or impaired T cell functionality. Cancer-associated fibroblasts (CAF) create an imbalanced biomechanical force in the tumor by the deposition of extracellular matrix, and by their contractility and proteolytic activity. CAF are abundant in mismatch repair-deficient tumors and their presence is associated with poor disease outcome (Kalluri 2016). Clinical targeting of CAF has been challenging due to its heterogeneous nature. We propose to target CAF making use of commonly expressed fibroblast growth factor receptor (FGFR) and platelet-derived growth factor receptor (PDGFR) or protease activity by fibroblast-activation protein (FAP). The advantage of FGFR/PDGFR inhibitors and FAP inhibitors is their complementary targeting of CAF biology either growth/differentiation vs proteolysis. Thus, we will evaluate whether impeding immune cell infiltration/functionality by CAF could explain non-responsiveness to immune checkpoint inhibitors in patients with DNA mismatch repair-deficient tumors. To test this hypothesis we will make use of three work packages: Workpackage 1: Human DNA mismatch repair-deficient tumors will be analyzed for the spatial localization and organization of collagen fibers, CAF and T-cells and data will be correlated with clinicopathological parameters. Workpackage 2: Patient-derived CAF will be treated with FGFR/PDGFR inhibitors or FAP inhibitors and outcomes such as (neo)matrix deposition, collagen rearrangement, and contractility will be evaluated and the consequent functional impact on T-cell chemotaxis, proliferation and differentiation will be tested. Workpackage 3: Syngeneic mouse tumor models will be used to evaluate if CAF targeting may improve efficacy of immune checkpoint inhibitors (such as anti-PD-1). We anticipate that CAF targeting combined with immunotherapy will synergistically induce and sustain the anti-tumor immune response, resulting in durable tumor regression in a larger population. Encouraging data in the preclinical study will enable fast translation into a clinical phase I/II trial.
Date:1 Sep 2019 →  31 Aug 2023
Keywords:CANCER ASSOCIATED FIBROBLASTS, PROTEASES
Disciplines:Cancer biology
Project type:Collaboration project