Antitumor immunity targeting fibroblast activation protein-α in a mouse Lewis lung carcinoma model

The tumor stromal microenvironment is an integral part of the occurrence and development of tumor. Cancer-associated fibroblasts (CAFs) are a key component of most tumor stromal microenvironments. The present study aimed to investigate the use of CAFs-targeted immunotherapy to fibroblast activation protein-α (FAP-α) expressed in CAFs. Recombinant adenoviral vectors containing the mouse FAP-α cDNA (rAd-FAP-α) were constructed. C57BL/6 mice were immunized with rAd-FAP-α infected dendritic cells (DCs) against FAP-α, which is overexpress in CAFs. The results demonstrated that mice vaccinated with rAd-FAP-α DCs gave rise to potent FAP-α-specific cytotoxic T lymphocytes capable of lysing Lewis lung cancer (LLC) CAFs. Furthermore, mice vaccinated with rAd-FAP-α-transduced DCs induced an effective therapeutic or protective antitumor immunity to LLC in a subcutaneous model, and prolonged overall survival time compared with mice vaccinated with the control recombinant adenovirus-transduced DCs (rAd-c DCs) or DCs alone. The results of the present study suggested that FAP-α, which is preferentially expressed in CAFs, may be considered as a potential target for killing or destroying CAFs within the tumor stromal microenvironment, and may be exploited to develop immunogenic tumor vaccines.