Effective Immunotherapy against Murine Gliomas Using Type 1 Polarizing Dendritic Cells—Significant Roles of CXCL10

Abstract

In an attempt to develop effective vaccines against central nervous system (CNS) tumors, we evaluated the ability of vaccines with standard dendritic cells (DC) versus type 1 polarizing DCs (DC1) to induce glioma-specific type 1 CTLs with CNS tumor-relevant homing properties and the mechanism of their action. C57BL/6 mouse-derived bone marrow cells were cultured with mouse granulocyte/macrophage colony-stimulating factor (GM-CSF) for 6 days, and CD11c+ cells were subsequently cultured with GM-CSF, rmIFN-γ, rmIFN-α, rmIL-4, and polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose for 24 hours to generate DC1s. In analogy to their human counterparts, mouse DC1s exhibited surface marker profiles of mature DCs and produced high levels of IL-12 and CXCL10. Importantly for their application as cancer vaccines, such DC1s stably retained their type 1 phenotype even when exposed to type 2-promoting or regulatory T cell (Treg)-promoting environments. Consistently, mouse DC1s induced antigen-specific type 1 CTLs more efficiently than nonpolarized DCs in vitro. DC1s given s.c. migrated into draining lymph nodes, induced antigen-specific CTLs, and suppressed Treg accumulation. In addition, s.c. immunization with DC1s loaded with glioma-associated antigen (GAA)-derived CTL epitope peptides prolonged the survival of CNS GL261 glioma-bearing mice, which was associated with efficient CNS glioma homing of antigen-specific CTLs. Intratumoral injections of GAA peptide-loaded DC1s further enhanced the anti-CNS glioma effects of DC1-based s.c. immunization. Interestingly, the antitumor functions were abrogated with CXCL10−/− mouse-derived DC1s. Collectively, these findings show the anti-CNS glioma effects of DC1-based therapy and a novel role of CXCL10 in the immunologic and therapeutic activity of DC-based cancer vaccines.

Isocitrate dehydrogenase mutations suppress STAT1 and CD8+ T cell accumulation in gliomas

“…Our findings highlight what we believe to be a novel mechanism of immune evasion and demonstrate that mutations in IDH suppress chemokines critical for the accumulation of CD8 + T cells in the tumor. We have previously reported the importance of CXCL10 in the recruitment of CD8 + T cells to murine gliomas (11,13,31) and the preliminary clinical activity of vaccinations with α-type 1-polarized DCs, which induced CXCL10 production in patients with GBM (32). Our data in the current study corroborated these previous observations in both clinical and preclinical Results were analyzed by log-rank (Mantel-Cox) and 1-way ANOVA with Dunnett's multiple comparisons test for data sets in A and C, respectively.…”

“…C57BL/6j mice used for the study were purchased from The Jackson Laboratory. The procedure used in the current study has been described previously (13,61). Briefly, using a Hamilton syringe (Hamilton Company), 1 × 10 5 GL261-WT or GL261-MUT cells in 2 μl PBS were stereotactically injected through an entry site from the bregma, 3 mm to the right of sagittal suture, and 3.0 mm below the surface of the skull of anesthetized mice by using a stereotactic frame (Kopf).…”

“…9,10). We have demonstrated that tumor-specific type 1 CD8 + T cells, which predominantly secrete IFN-γ, but not type 2 CD8 + T cells, can efficiently traffic into brain tumor sites and mediate effective tumor cell killing (11) via the type 1 chemokine CXCL10 (11)(12)(13)(14). Despite the importance of the type 1 T cell response, gliomas and other cancers secrete numerous type 2 cytokines (15-17) that promote tumor proliferation (18,19) and immune escape (20)(21)(22).…”

The emerging role of CXCL10 in cancer (Review)

“…Immune modulation of CXCL10 has been widely used to modify dendritic cells to increase vaccine potency. Numerous investigators have confirmed that the CXCL10 gene has significant synergistic effects against tumors through its immunomodulatory properties by recruiting immature antigen-presenting, dentritic or early activated T cells into the tumor in murine glioma and the melanoma model (58)(59)(60).…”

Influx and Efflux of Immune Cells in the Central Nervous System

“…CXCR3 interacts with the following chemokines: CXCL9, CXCL10, and CXCL11. In particular, the CXCR3-CCL10 axis is associated with the influx of type-1 CTLs (Tc1; the most potent effector T cells against CNS tumors) into the CNS tumor sites [4][5][6]. In other words, CXCR3 is preferentially upregulated on Tc1, which is critical for efficient CNS tumor-homing of Tc1.…”