CXCR3/CXCR3 ligand biological axis impairs RENCA tumor growth by a mechanism of immunoangiostasis

J Pan, MD Burdick, JA Belperio, YY Xue… - The Journal of …, 2006 - journals.aai.org
J Pan, MD Burdick, JA Belperio, YY Xue, C Gerard, S Sharma, SM Dubinett, RM Strieter
The Journal of Immunology, 2006journals.aai.org
Metastatic renal cell carcinoma (RCC) responds poorly to chemo-or radiation therapy but
appears to respond to systemic immunotherapy (ie, IL-2 and/or IFN-α), albeit with only 5–
10% durable response. The CXCR3/CXCR3 ligand biological axis plays an important role in
mediating type 1 cytokine-dependent cell-mediated immunity, which could be beneficial for
attenuating RCC if optimized. We found that systemic IL-2 induced the expression of CXCR3
on circulating mononuclear cells but impaired the CXCR3 ligand chemotactic gradient from …
Abstract
Metastatic renal cell carcinoma (RCC) responds poorly to chemo-or radiation therapy but appears to respond to systemic immunotherapy (ie, IL-2 and/or IFN-α), albeit with only 5–10% durable response. The CXCR3/CXCR3 ligand biological axis plays an important role in mediating type 1 cytokine-dependent cell-mediated immunity, which could be beneficial for attenuating RCC if optimized. We found that systemic IL-2 induced the expression of CXCR3 on circulating mononuclear cells but impaired the CXCR3 ligand chemotactic gradient from plasma to tumor by increasing circulating CXCR3 ligand levels in a murine model of RCC. Moreover, the antitumor effect of systemic IL-2 was CXCR3-dependent, as IL-2 failed to inhibit tumor growth and angiogenesis in CXCR3−/− mice. We hypothesized that the immunotherapeutic effect of the CXCR3/CXCR3 ligand biological axis could be optimized by first priming with systemic IL-2 to induce CXCR3 expression on circulating mononuclear cells followed by enhancing the intratumor CXCR3 ligand levels to establish optimal CXCR3-dependent chemotactic gradient. We found that combined systemic IL-2 with an intratumor CXCR3 ligand (CXCL9) lead to significantly greater reduction in tumor growth and angiogenesis, increased tumor necrosis, and increased intratumor infiltration of CXCR3+ mononuclear cells, as compared with either IL-2 or CXCL9 alone. The enhanced antitumor effect of the combined strategy was associated with a more optimized CXCR3-dependent chemotactic gradient and increased tumor-specific immune response. These data suggest that the combined strategy of systemic IL-2 with intratumor CXCR3 ligand is more efficacious than either strategy alone for reducing tumor-associated angiogenesis and augmenting tumor-associated immunity, the concept of immunoangiostasis.
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