Subcritical Water Extracts from <i>Agaricus blazei</i> Murrill’s Mycelium Inhibit the Expression of Immune Checkpoint Molecules and Axl Receptor

• Main Authors: Taro Yasuma, Masaaki Toda, Hajime Kobori, Naoto Tada, Corina N. D’Alessandro-Gabazza, Esteban C. Gabazza
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Journal of Fungi
• Subjects: mushroom; immune checkpoints; Axl receptor; lung cancer; dendritic cells; immune response
• Online Access: https://www.mdpi.com/2309-608X/7/8/590

<i>Agaricus blazei</i> Murrill or Himematsutake is an edible and medicinal mushroom. <i>Agaricus blazei</i> Murrill’s fruiting body extracts have anticancer properties, although the mechanism is unknown. Basic or organic solvents, which are hazardous for human health, are generally used to prepare <i>Agaricus blazei</i> Murrill’s extracts. The inhibition of immune checkpoint molecules and Axl receptor is an effective therapy in cancer. This study assessed whether subcritical water extracts of the <i>Agaricus blazei</i> Murrill’s fruiting body or mycelium affect the expression of Axl and immune checkpoint molecules in lung cancer cells. We used A549 cells and mouse bone marrow-derived dendritic cells in the experiments. We prepared subcritical water extracts from the <i>Agaricus blazei</i> Murrill’s fruiting body or mycelium. The subcritical water extracts from the <i>Agaricus blazei</i> Murrill’s fruiting body or mycelium significantly inhibited the expression of immune checkpoint molecules and Axl compared to saline-treated cells. Additionally, the hot water extract, subcritical water extract, and the hot water extraction residue subcritical water extract from the <i>Agaricus blazei</i> Murrill’s mycelium significantly enhanced the expression of maturation markers in dendritic cells. These observations suggest that the subcritical water extract from <i>Agaricus blazei</i> Murrill’s mycelium is a promising therapeutic tool for stimulating the immune response in cancer.