RESUMO
Gemcitabine (GEM) is a commonly used drug in the clinical treatment of non-small cell lung cancer. Due to the accumulation of cells mediating immune escape and T cell depletion after chemotherapy, tumor microenvironment (TME) tends to be immunosuppressive status, which ultimately leads to tumor metastasis. The experimental protocol was approved by the Medical Laboratory Animal Ethics Committee of Jiangsu Provincial Academy of Chinese Medicine. Therefore, we observed the immunomodulatory effects of micro-particulate Ganoderma lucidum spore β-glucan (PGSG) on macrophages in vitro experiments. Next, mice subcutaneous Lewis lung cancer models were established to observe the anti-tumor effects of PGSG through oral administration of PGSG combined with GEM. Flow cytometry analysis was used to analyze the ratio of anti-tumor T cells in tumors and spleen, as well as the proportion of myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM) and regulatory cells (Tregs). The results showed that PGSG can up-regulate the expression of major histocompatibility antigens (MHC-II), CD40, CD86 and CD80 on the surface of macrophages, enhance the ability to phagocytosis of neutral red and further mediate the release of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4) and interleukin-10 (IL-10). In vivo experiments, combined administration can significantly decrease the volume and weight of tumors, reduce the ratio of MDSC (CD11b+Gr-1+), M-MDSC (CD11b+Ly6G-Ly6Chigh) and Treg (CD4+Foxp3+). At the same time, PGSG promoted the conversion of M2 (F4/80+CD206+) to M1 (F4/80+MHC-II+) and enhanced the response of helper T cell-1 (Th1) (CD4+IFN-γ+) and cytotoxic T lymphocyte (CTL) (CD8+IFN-γ+), which is of great significance for killing tumors. These results suggest that PGSG can regulate innate and adaptive antitumor immune responses, reshape the immunosuppressive microenvironment and enhance the anti-lung cancer effect of GEM.
RESUMO
In this study, an immunostimulating particulate β-glucan was isolated from a hot alkaline extract of the fruiting bodies of Ganoderma lucidum. The optimum conditions of 8 hours treatment time, 1∶20 solid - liquid ratio and 55 ℃ for the alkaline extract process were obtained after investigating by single-factor experiments and Box-Benhnken design in terms of the Ganoderma lucidum particulate β-glucan (GLG) increment, and these conditions resulted in a GLG yield of 8.57%. The experimental protocol was approved by the Medical Laboratory Animal Ethics Committee of Jiangsu Provincial Academy of Chinese Medicine. The result showed that resident macrophages were effectively activated by GLG, such as with the up-regulation of co-stimulatory molecules, the secretion of cytokines and phagocytic uptake. GLG could also promote the proliferation of spleen lymphocytes in mice. In addition, IFN-γ production of spleen CD4+ T cells and cytotoxic T lymphocyte (CTL) responses were significantly enhanced on GLG orally treatment, which ultimately resulted in significantly decreased tumor burden. Taken together, these data suggest that GLG might act as an immune stimulator to exert antitumor effects.