Antitumor immune response induced by i.t. injection of vector-activated dendritic cells and chemotherapy suppresses metastatic breast cancer.

S.c. injection of the Ad-sig-tumor-associated antigen (TAA)/ecdCD40L vector vaccine has been shown to induce a CD8 immune response against TAA for up to 1 year. The first goal of this article is to test if the injection of autologous dendritic cells infected ex vivo with the Ad-sig-TAA/ecdCD40L can increase the immune response induced against TAA. The second goal is to test the effect of adding local chemotherapy in the form of i.t. injection of the AdCDIRESE1A vector-directed chemotherapy on the immune response induced by i.t. injection of adenoviral vector-activated dendritic cells. The results show that the i.t. injection of the AdCDIRESE1A chemotherapy sensitization vector, which encodes the cytosine deaminase chemotherapy sensitization transcription unit, to the i.t. injection of Ad-sig-ecdCD40L vector-infected dendritic cells increased the level of suppression of the growth of the CCL-51 breast cancer cells. The combination of i.t. injection of the AdCDIRESE1A chemotherapy sensitization vector and Ad-sig-ecdCD40L vector-infected dendritic cells into s.c. CCL-51 breast cancer nodules suppressed the growth of uninjected metastatic tumor nodules in the lung. Finally, adding the i.t. injection of the AdCDIRESE1A chemotherapy sensitization vector to the i.t. administration of dendritic cells infected with a rat HER-2/neu (rH2N)-expressing vector (Ad-sig-rH2N/ecdCD40L) led to the induction of rH2N-specific antitumoral immunity in rH2N transgenic mice (which are anergic to the rH2N antigen). This anti-rH2N immune response suppressed the growth of established H2N-positive NT2 breast cancer more efficiently than did the vector-targeted chemotherapy or Ad-sig-rH2N/ecdCD40L-infected dendritic cell vaccine alone.