1. Local Interleukin-12 Treatment Enhances the Efficacy of Radiation Therapy by Overcoming Radiation-Induced Immune Suppression.
- Author
-
Yu CF, Chang CH, Wang CC, Hong JH, Chiang CS, and Chen FH
- Subjects
- Actins metabolism, Animals, CD8-Positive T-Lymphocytes metabolism, Immunohistochemistry, Immunosuppressive Agents pharmacology, Immunotherapy, Interferon-gamma metabolism, Liver metabolism, Liver pathology, Lymphocytes, Tumor-Infiltrating immunology, Male, Mice, Mice, Inbred C57BL, Muscle, Smooth metabolism, Neoplasm Transplantation, Pericytes metabolism, Prostatic Neoplasms metabolism, Tumor Microenvironment immunology, Immune System radiation effects, Interleukin-12 Subunit p35 metabolism, Radiotherapy methods
- Abstract
Radiation therapy (RT) recruits myeloid cells, leading to an immunosuppressive microenvironment that impedes its efficacy against tumors. Combination of immunotherapy with RT is a potential approach to reversing the immunosuppressive condition and enhancing tumor control after RT. This study aimed to assess the effects of local interleukin-12 (IL-12) therapy on improving the efficacy of RT in a murine prostate cancer model. Combined treatment effectively shrunk the radioresistant tumors by inducing a T helper-1 immune response and influx of CD8+ T cells. It also delayed the radiation-induced vascular damage accompanied by increased α-smooth muscle actin-positive pericyte coverage and blood perfusion. Moreover, RT significantly reduced the IL-12-induced levels of alanine aminotransferase in blood. However, it did not further improve the IL-12-induced anti-tumor effect on distant tumors. Upregulated expression of T-cell exhaustion-associated genes was found in tumors treated with IL-12 only and combined treatment, suggesting that T-cell exhaustion is potentially correlated with tumor relapse in combined treatment. In conclusion, this study illustrated that combination of radiation and local IL-12 therapy enhanced the host immune response and promoted vascular maturation and function. Furthermore, combination treatment was associated with less systemic toxicity than IL-12 alone, providing a potential option for tumor therapy in clinical settings.
- Published
- 2021
- Full Text
- View/download PDF