Lentinan Treatment Suppressed Breast Cancer Progression by Decreasing IL-35 and iTr35 Subpopulation

Abstract

Purpose: Lentinan, a traditional Chinese herbal component that is isolated from shiitake mushrooms, shows prominent antitumor activity. This study aims to evaluate the treatment effects and possible mechanisms of Lentinan on mouse breast cancer. Methods: A 4T1 mouse breast cancer cells were subcutaneously injected into BALB/c mice to establish a breast cancer bearing mice model. Then mice were intragastrically administrated with Lentinan in varying doses at 100 mg/kg, 200 mg/kg, and 400 mg/kg, respectively, once a day for 14 days. After Lentinan treatment, the peripheral blood of the mice was obtained and subjected to ELISA (enzyme linked immunosorbent assay) to analyze the levels of serum IFN-γ (Interferon-γ), IL-4 (Interleukin-4) and IL-35 (Interleukin-35). The tumors, thymus, spleens, and lymph node tissues were concurrently collected from the mice to evaluate IL-35 expression and iTr35 (IL-35-producing regulatory T cells) subpopulation by qRT-PCR (reverse transcription quantitative real-time PCR), Western Blot, and Flow Cytometry. Results: Mice treated with Lentinan improved their quality of life, suppressed tumor progression, decreased the serum IL-35 level, the expressions of p35 and EBI3 (Epstein-Barr virus-induced gene 3) in lymph nodes and spleen tissues and reduced the percentages of CD4⁺ T cell (cluster of differentiation 4⁺ T cell) and iTr35 subpopulations in peripheral blood and spleens compared to the control mice. However, IFN-γ level increased, especially in the group at the 200 mg/kg dosage in the Lentinan treated mice compared to the control mice. Conclusions: Lentinan was shown as immunomodulator actor to improve antitumor activity by improving the IFN-γ, decreasing the IL-35 expression, and reducing the iTr35 cell subpopulation in the 4T1 breast cancer-bearing mice.