Supplementary Figures 1-3 from Adoptive Transfer of Type 1 CTL Mediates Effective Anti–Central Nervous System Tumor Response: Critical Roles of IFN-Inducible Protein-10
Interleukin (IL)-4 exhibits strong antitumor effects and IL-4 gene therapy has been used clinically in the treatment of some types of cancer. In the present study, we evaluated the efficacy of IL-4-transduced tumor cell vaccines in combination with blockade of programmed cell death 1 (PD-1) and investigated the mechanisms underlying the antitumor effects of this therapy. A poorly immunogenic murine colorectal cancer cell line (i.e. MC38) was transduced to overexpress IL-4. In a therapeutic model, MC38-IL4 cells and anti-PD-1 antagonistic antibodies (Ab) were inoculated into parental tumor-bearing mice. Immunohistochemical analyses and tumor-specific lysis were also performed. Additive antitumor effects were observed when mice were treated with IL-4 in combination with an anti-PD-1 Ab. Immunohistochemical analysis of the therapeutic model showed marked infiltration of CD4+ and CD8+ cells into established MC38 tumors of mice treated with anti-PD-1 Ab. Significant tumor-specific cytolysis was detected when the splenocytes of mice treated with both IL-4 and anti-PD-1 Ab were used as effector cells. These results suggest that blockade of the interaction between PD-1 and programmed death ligand 1 (PD-L1) enhances the antitumor immune responses induced by IL-4. Thus, IL-4 gene-transduced tumor cell vaccines in combination with PD-1 blockade may be considered as possible candidates for clinical trials of new cancer vaccines.
Abstract The development of effective immunotherapeutic strategies for central nervous system (CNS) tumors requires a firm understanding of factors regulating the trafficking of tumor antigen–specific CTLs into CNS tumor lesions. Using C57BL/6 mice bearing intracranial (i.c.) ovalbumin-transfected melanoma (M05), we evaluated the efficacy and tumor homing of i.v. transferred type 1 or 2 CTLs (Tc1 or Tc2, respectively) prepared from ovalbumin-specific T-cell receptor–transgenic OT-1 mice. We also tested our hypothesis that intratumoral (i.t.) delivery of dendritic cells that had been transduced with IFN-α cDNA (DC-IFN-α) would enhance the tumor-homing and antitumor effectiveness of adoptively transferred Tc1 via induction of an IFN-γ-inducible protein 10 (IP-10). In vitro, DC-IFN-α induced IP-10 production by M05 and enhanced the cytolytic activity of Tc1. In vivo, i.v. transferred Tc1 trafficked efficiently into i.c. M05 and mediated antitumor responses more effectively than Tc2, and their effect was IP-10 dependent. I.t. injections of DC-IFN-α remarkably enhanced the tumor homing, therapeutic efficacy, and in situ IFN-γ production of i.v. delivered Tc1, resulting in the long-term survival and persistence of systemic ovalbumin-specific immunity. These data suggest that Tc1-based adoptive transfer therapy may represent an effective modality for CNS tumors, particularly when combined with strategies that promote a type 1 polarized tumor microenvironment. (Cancer Res 2006; 66(8): 4478-87)
