Comparative Genomics Across Ganoderma Species to Identify Secondary Metabolite Clusters with Cytotoxic Properties

Comparative Genomics Across Ganoderma Species to Identify Secondary Metabolite Clusters with Cytotoxic Properties

Alvin Sherman Library

Fungi in the genus Ganoderma have been widely studied in Chinese culture for their medicinal properties and promoting overall health and longevity. Our prior work on eight Ganoderma species showed that they contain Secondary Metabolite Clusters (SMCs) that code for multiple terpenes, betalactones, and ribosomally synthesized and post-translationally modified peptides (RiPPs). These compounds are well known for their cytotoxic and anticancer potential. Using the bioinformatics platform antiSMASH, we previously identified and annotated the specific SMCs within these genomes that are predicted to produce such bioactive metabolites. To test the results obtained from the bioinformatics analysis, fungal extracts were prepared from G. lucidum and G. zonatum by air-drying and powdering the mushroom fruiting bodies, mixing them with 95% ethanol, followed by lyophilization. Different dilutions of these extracts were used for proliferation assays on two cancer stem cell (CSC) models, i.e. patient-derived glioma stem cells (GSCs); PN84 and GSC17 to assess the cytotoxicity potential of the fungal compounds. Proliferation was measured at 24, 48, and 72 hours, and survival analysis showed significant reductions in PN84 viability by 72 hours at 100 ppm for both extracts. Comparative transcriptomic analysis of both the fungi and the treated cancer cells will define the pathways/gene-expression changes associated with metabolite production and cytotoxic response, with qRT-PCR used for targeted validation. These findings provide experimental support for the anticancer potential of Ganoderma metabolites and justify continued investigation of these natural products for pharmacological and nutritional applications.