Culture Conditions for Mycelial Growth and Anti-Cancer Properties of Termitomyces

Abstract

Termitomyces sp. that grow in symbiosis with fungus-farming Termites have medicinal properties. However, they are rare in nature, and their artificial culture is challenging. The expression of AXL receptor tyrosine kinase and immune checkpoint molecules favor the growth of cancer cells. The study evaluated the optimal conditions for the artificial culture of Termitomyces and their inhibitory activity on AXL and immune checkpoint molecules in lung adenocarcinoma and melanoma cell lines. The culture of 45 strains of Termitomyces was compared. Five strains with marked growth rates were selected. Four of the selected strains form a single cluster by sequence analysis. The mycelium of 4 selected strains produces more fungal mass in potato dextrose broth than in a mixed media. The bark was the most appropriate solid substrate for Termitomyces mycelia culture. The mycelium of all five selected strains showed a higher growth rate under normal CO₂ conditions. The culture broth, methanol, and ethyl acetate of one selected strain (T-120) inhibited the mRNA relative expression of AXL receptor tyrosine kinase and immune checkpoint molecules in cancer cell lines. Overall, these results suggest the potential usefulness of Termitomyces extracts as a co-adjuvant therapy in malignant diseases.

Keywords:

• Edible mushroom
• Termitomyces
• AXL
• PD-L1
• PD-L2
• artificial culture

Acknowledgments

The authors want to thank all people who cooperated in the mushroom collection.

Author contributions

I.K.: conceptualization. E.C.G.: methodology. S.T., M.T., and T.K.: formal analysis. S.T., M.T., C.N.D-G., and T.Y.: resources. E.C.G., T.K., T.T., and I.K.: writing—original draft preparation. S.T., T.Y., and E.C.G.: writing—review and editing. E.C.G. and I.K.: funding acquisition. All authors have read and agreed to the published version of the manuscript.

Disclosure statement

E.C.G. and I.K. have a pending patent on the discovery reported in this article. Other authors declared no conflict of interest regarding this work.

Data availability statement

All data are available from the corresponding author under reasonable request.

Additional information

Funding

The Japan Society partly supported this research for the Promotion of Science (Kakenhi No. 20H03048). However, the funders had no role in the design of the study; in the collection, analysis, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.