Brunekreeft KL, Strohm C, Gooden MJ, Rybczynska AA, Nijman HW, Grigoleit GU, Helfrich W, Bremer E, Siegmund D, Wajant H, de Bruyn M. Targeted delivery of CD40L promotes restricted activation of antigen-presenting cells and induction of cancer cell death.
Mol Cancer 2014;
13:85. [PMID:
24741998 PMCID:
PMC4022212 DOI:
10.1186/1476-4598-13-85]
[Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/08/2014] [Indexed: 12/11/2022] Open
Abstract
Background
Stimulation of CD40 can augment anti-cancer T cell immune responses by triggering effective activation and maturation of antigen-presenting cells (APCs). Although CD40 agonists have clinical activity in humans, the associated systemic activation of the immune system triggers dose-limiting side-effects.
Methods
To increase the tumor selectivity of CD40 agonist-based therapies, we developed an approach in which soluble trimeric CD40L (sCD40L) is genetically fused to tumor targeting antibody fragments, yielding scFv:CD40L fusion proteins. We hypothesized that scFv:CD40L fusion proteins would have reduced CD40 agonist activity similar to sCD40L but will be converted to a highly agonistic membrane CD40L-like form of CD40L upon anchoring to cell surface exposed antigen via the scFv domain.
Results
Targeted delivery of CD40L to the carcinoma marker EpCAM on carcinoma cells induced dose-dependent paracrine maturation of DCs ~20-fold more effective than a non-targeted control scFv:CD40L fusion protein. Similarly, targeted delivery of CD40L to the B cell leukemia marker CD20 induced effective paracrine maturation of DCs. Of note, the CD20-selective delivery of CD40L also triggered loss of cell viability in certain B cell leukemic cell lines as a result of CD20-induced apoptosis.
Conclusions
Targeted delivery of CD40L to cancer cells is a promising strategy that may help to trigger cancer-localized activation of CD40 and can be modified to exert additional anti-cancer activity via the targeting domain.
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