Gamma-irradiated β-glucan induces immunomodulation and anticancer activity through MAPK and NF-κB pathways.

Abstract

This study was designed to evaluate the antitumor activity of low-molecular-weight β-glucan (LMBG) produced by gamma irradiation (50 kGy), using in vivo and in vitro models. The results indicate that treatment with LMBG increased the proliferation of murine peritoneal macrophages, and their production of tumor necrosis factor α and nitric oxide, to a greater extent than treatment with high-molecular-weight β-glucan (HMBG). The activation of peritoneal macrophages by LMBG was mediated by both mitogen-activated protein kinases and nuclear factor-κB signaling. Interestingly, when administered prophylactically, LMBG significantly inhibited tumor growth and lung metastasis in mice injected with B16BL6 melanoma cells compared with the HMBG-treated group. In comparison with HMBG treatment, LMBG treatment also elevated cell proliferation, cytokine (interferon-γ and interleukin-2) production, and CD8(+) T cell populations in splenocytes from tumor-bearing mice. These data indicate that LMBG is important in eliciting antitumor activity through a non-specific immune response and may play a major role as a value-added product in the medical industry.