Tumor immunotherapy targeting fibroblast activation protein, a product expressed in tumor-associated fibroblasts

J Lee, M Fassnacht, S Nair, D Boczkowski, E Gilboa - Cancer research, 2005 - AACR
J Lee, M Fassnacht, S Nair, D Boczkowski, E Gilboa
Cancer research, 2005AACR
Murine studies have shown that immunologic targeting of the tumor vasculature, a key
element of the tumor stroma, can lead to protective immunity in the absence of significant
pathology. In the current study, we expand the scope of stroma-targeted immunotherapy to
antigens expressed in tumor-associated fibroblasts, the predominant component of the
stroma in most types of cancer. Mice were immunized against fibroblast activation protein
(FAP), a product up-regulated in tumor-associated fibroblasts, using dendritic cells …
Abstract
Murine studies have shown that immunologic targeting of the tumor vasculature, a key element of the tumor stroma, can lead to protective immunity in the absence of significant pathology. In the current study, we expand the scope of stroma-targeted immunotherapy to antigens expressed in tumor-associated fibroblasts, the predominant component of the stroma in most types of cancer. Mice were immunized against fibroblast activation protein (FAP), a product up-regulated in tumor-associated fibroblasts, using dendritic cells transfected with FAP mRNA. Using melanoma, carcinoma, and lymphoma models, we show that tumor growth was inhibited in tumor-bearing mice vaccinated against FAP and that the magnitude of the antitumor response was comparable to that of vaccination against tumor cell–expressed antigens. Both s.c. implanted tumors and lung metastases were susceptible to anti-FAP immunotherapy. The antitumor response could be further enhanced by augmenting the CD4+ T-cell arm of the anti-FAP immune response, achieved by using a lysosomal targeting sequence to redirect the translated FAP product into the class II presentation pathway, or by covaccination against FAP and a tumor cell–expressed antigen, tyrosinase-related protein 2. No morbidity or mortality was associated with anti-FAP vaccination except for a small delay in wound healing. The study suggests that FAP, a product which is preferentially expressed in tumor-associated fibroblasts, could function as a tumor rejection antigen in a broad range of cancers.
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