Modulation of peritumoral fibroblasts with a membrane-tethered tissue inhibitor of metalloproteinase (TIMP) for the elimination of cancer cells.

ABSTRACT

BACKGROUND: Peritumoral fibroblasts are key components of the tumor microenvironment. Through remodeling of the extracellular matrix (ECM) and secretion of pro-tumorigenic cytokines, peritumoral fibroblasts foster an immunosuppressive milieu conducive to tumor cell proliferation. In this study, we investigated if peritumoral fibroblasts could be therapeutically engineered to elicit an anti-cancer response by abolishing the proteolytic activities of membrane-bound metalloproteinases involved in ECM modulation. METHODS: A high affinity, glycosylphosphatidylinositol (GPI)-anchored Tissue Inhibitor of Metalloproteinase (TIMP) named "T1PrαTACE" was created for dual inhibition of MT1-MMP and TACE. T1PrαTACE was expressed in fibroblasts and its effects on cancer cell proliferation investigated in 3D co-culture models. RESULTS: T1PrαTACE abrogated the activities of MT1-MMP and TACE in host fibroblasts. As a GPI protein, T1PrαTACE could spontaneously detach from the plasma membrane of the fibroblast to co-localize with MT1-MMP and TACE on neighboring cancer cells. In a 3D co-culture model, T1PrαTACE promoted adherence between the cancer cells and surrounding fibroblasts, which led to an attenuation in tumor development. CONCLUSION: Peritumoral fibroblasts can be modulated with the TIMP for the elimination of cancer cells. As a novel anti-tumor strategy, our approach could potentially be used in combination with conventional chemo- and immunotherapies for a more effective cancer therapy.