In a recent study published in the journal Dr Medical Science Forum, Researchers in Portugal have expanded on previous studies that demonstrated anti-cancer activity of a small RNA (sRNA) fraction derived from it. Cantharellus cibarius (CCI), a golden chanterelle mushroom. The present study investigates the anticancer potential of sRNA Boletus edulis (porcini) and Agaricus bisporus (Portobello). Whether these mushroom microRNAs may have anti-cancer properties is additionally evaluated.
Study: Mushroom4Life: Decoding the Molecular Basis of a Cancer-Fighting Small RNA Extracted from Edible Mushrooms. Image credit: JeannieR/Shutterstock
Experiments on normal and cancer cell lines revealed that while all mushroom sRNAs exhibit anti-cancer properties, their relative activities vary widely, suggesting that anti-cancer sRNAs are enriched in specific sequences. These results highlight the potential of mushrooms as a source of biomolecules with anti-cancer potential and illustrate the need for further research into commonly available fruits, vegetables and (in this case) fungi with the potential to discover significant bioactives with significant therapeutic applications.
A brief history of mushroom applications in cancer research
Mushroom is the common name for the conspicuous umbrella-shaped fruiting body (sporophore) of certain fungi. Despite more than 14,000 described species of this fungus, only a fraction are safe for human consumption. These few species, however, are staples of the diet across nearly every culture and civilization. Some (mainly Asian) cultures have used ‘medicinal mushrooms’ to treat infections for hundreds of years, yet global interest in the clinical properties of mushrooms has, until recently, been largely ignored.
With increasing interest in bioprospecting (the scientific search for natural biochemical or genetic products with beneficial applications), medical research has begun screening mushroom biomolecules for potential pharmaceutical applications. In recent decades, a plethora of nutraceuticals with antioxidant, anti-cancer, anti-inflammatory, and neurologically beneficial abilities have been described. Mushroom anti-cancer research has recently received special attention due to the isolated description of water-soluble small RNA (sRNA) fractions. Cantharellus cibarius (CCI) and Boletus edulis (BED) depicts potent apoptosis-inducing and cell proliferation-inhibiting effects.
Unfortunately, the mechanisms of action of these sRNAs remain unknown. Identifying these mechanisms and expanding the sampling of mushroom species will benefit both the medical and nutritional industries – the former as it will lay the groundwork for future research to optimize these anticancer benefits (dose, potential alive toxicity) and the latter further advancing the case for the nutritional benefits of this treasure trove of nutraceuticals.
About the study
In the current study, BED and Agaricus bisporus (ABI), commonly known as Portobello, two untested mushroom species collected from Tras-os-Montes and Alto Douro (Portugal), were compared with sRNA fractions from CCI to investigate the potential anti-cancer efficacy of their sRNAs. . Since previous work has hypothesized that microRNAs (miRNAs) may also serve anti-cancer functions, three species of miRNAs were also evaluated. All samples were freeze-dried (lyophilized) after harvest to prevent RNA degradation and maintain sample freshness.
sRNAs were extracted using anion-exchange chromatography using the protocol described by Lemizec et al. miRNAs were extracted using the MirVana miRNA isolation kit. for alive For efficacy evaluation, Caco-2 tumor cell line and HDFn normal cell line were used. Metrics of drug susceptibility were MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) test in conjunction with spectrophotometric measurements. Finally, RNA fluorescence in situ hybridization (RNA-FISH) experiments were used to visualize target messenger RNA transcripts in cultured cells. Statistical significance of results was verified using one-way analysis of variance (ANOVA) test.
Purification of BED resulted in two unique sRNA fractions, named BEDA and BEDB. Surprisingly, ABI purification produced only one fraction (ABIA), indicating that not all mushrooms (or their sRNAs) are chemically and functionally identical.
Cell line evaluation of sRNA efficacy revealed that ABIA was able to suppress cancer cell viability at a concentration of 50 μg/mL. Although higher concentrations suppress cancer more effectively, they prove cytotoxic to normal cells and thus further studies are needed to elucidate their ideal doses. In contrast, BEDA did not show any anti-cancer properties.
BEDB and CCI3 proved to be the best anti-cancer agents, with high anti-cancer efficacy at low doses and normal cell cytotoxicity only at a much higher concentration (250 µg/mL). The miRNA BED and ABI results differ from the previously reported CCI3 results, showing no statistically significant difference between cancer and normal cells, reducing their effectiveness as anti-cancer therapeutics.
“Despite similar purity and molecular weight when compared to CCI3 and BEDB fractions, BEDS and BEDH samples did not show the same biological effects. These data suggest a different primary structure of sRNA and a sequence-dependent effect. To understand whether the effect of CCI3 and BEDB was sequence-dependent and whether the sequence isolated in these fractions was similar, we conducted an RNA-FISH in Caco-2 cells that had not been treated with CCI3 and BEDB for 96 h. , using a clone isolated from CCI3 as a probe.”
RNA-FISH results revealed that the BEDB and CCI3 fractions were more than 80% similar in their genetic sequences, suggesting that both fractions are enriched in the same sRNA sequence.
“However, further functional studies will be needed to understand their targets in cells and the mechanisms behind their anti-tumor potential.”
- Sá, I., Ribeiro, M., Nunes, FM, Marques, G., Chaves, R., & Ferreira, D. (2024). Mushroom4Life: Decoding the molecular basis of a cancer-fighting small RNA extracted from an edible mushroom. Medical Science Forum, 23(1), 9, DOI – 10.3390/msf2023023009, https://www.mdpi.com/2673-9992/23/1/9