Lentinan Inhibits Tumor Progression by Immunomodulation in a Mouse Model of Bladder Cancer

Background: Lentinan (LNT), an isolated traditional Chinese herbal component, has antitumor potential. In the current study, the intrinsic mechanism of LNT-induced immunity against bladder cancer was explored in a mouse model. Methods: In the mouse model of bladder cancer, we used flow cytometry to detect the LNT caused population changes of T cells, macrophages, MDSC cells, and Treg cells. ELISA was used to evaluate cytokines expression in the supernatant of splenocytes. Results: We found that the administration of LNT increased the proportions of CD3(+)CD4(+) and CD3(+)CD8(+) T cell subsets as well as CD11b(+)F480(+) macrophages, whereas it diminished the subpopulations of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) and Gr-1(+)CD11b(+) myeloid-derived suppressor cells (MDSCs). LNT also upregulated the expression of interferon (IFN)-γ and interleukin (IL)-12, accompanied by a significant reduction in IL-10 and tumor growth factor (TGF)-β (P < .05). Our research further confirmed the synergy between LNT and gemcitabine (GEM) to activate immunity and inhibit the growth of bladder tumors in mouse model. Conclusions: LNT induced macrophage activation, followed by the enhanced proliferation of CD4(+) and CD8(+) T cells, and the upregulated expression of IFN-γ and IL-2. Meanwhile, the proportions of MDSCs and Tregs were downregulated, leading to a reduced expression of the anti-inflammatory cytokines IL-10 and TGF-β. The synergy between LNT and GEM provides additional evidence supporting the application of this traditional Chinese herbal component for bladder cancer therapy.