Re-activation of anti-tumor immunity in cancer by target-restricted activation of receptors of the Tumor Necrosis Factor-family

Brunekreeft, K.L. (Kim) (2013) Re-activation of anti-tumor immunity in cancer by target-restricted activation of receptors of the Tumor Necrosis Factor-family. thesis, Medicine.

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Abstract

Infiltration of immune cells into ovarian cancer (OC) tumors is associated with an improved prognosis. However, the inevitable progression of the disease indicates that the immune system is incapable of mediating tumor regression. In part, this is due to insufficient immune-stimulation by members of the tumor necrosis family (TNF) family. In line with this, agonistic antibodies directed against specific TNF family receptors (TNFRs) mediate potent tumor regression in animal models. Nevertheless, systemic treatment with these antibodies in human trials is hampered by dose-limiting toxicity. Interestingly, low dose local administration of these antibodies can result in the same effect as high dose systemic administered agonistic antibodies. However, tumors are often inaccessible for such local intervention. Therefore, we developed an approach for selectively activating these (TNFRs) in the tumor micro-environment through targeted delivery of the corresponding ligand (TNFL) to tumor cells. Importantly, while the typically expressed transmembrane forms of TNFLs are active, soluble(-recombinant) TNFLs (sTNFLs) are largely inactive, but can be “re-activated” by cross-linking. In our approach, such cross-linking is achieved by targeted delivery to antigens on the tumor cell surface. Hence, the resultant therapeutics are essentially inactive “en route”, thereby minimizing side-effects, but regain full activity once bound to the tumor. Fusion proteins were engineered comprising a tumor-targeting domain (anti-EpCAM) genetically linked to the co-stimulatory CD40-ligand, which matures dendritic cells (DCs) thereby augmenting an anti-tumor T cell response. Subsequently the fusion protein was evaluated in vitro. In brief, co-cultures of EpCAM+ cell lines (and appropriate controls) +/- dendritic cells were treated with anti-EpCAM:CD40L and functional immune-parameters, such as IL-8 or IL-12 production were measured using ELISA. Anti-EpCAM:CD40L induced dose-dependent maturation of dendritic cells with concomitant T-cell activation in mixed leukocyte reactions. Targeted delivery of anti-EpCAM:CD40L significantly decreased the required dose of CD40L for DC maturation. Targeted delivery of co-stimulatory TNF-family ligands was effective at mediating tumor antigen-restricted activation/maturation of immune cells. These data provide proof-of-concept for local re-activation of anti-tumor immunity in the OC micro-environment. Subsequent in vivo studies with anti-EpCAM:CD40L will be performed.

Item Type:	Thesis (Thesis)
Supervisor name:	Nijman, Prof.dr. H.W. MD PhD and Bremer, Dr. E. and Kallenberg, Prof.dr. C.G.M.
Supervisor name:	Wajant, Prof.dr. H. and Bruyn, Dr. M. de and University Hospital Würzburg and Department of Molecular Internal Medicine
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:50
Last Modified:	25 Jun 2020 10:50
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/1109

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