Regulation of cancer cell signaling pathways by mushrooms and their bioactive molecules: Overview of the journey from benchtop to clinical trials

New insights into signaling pathways of cancer prevention effects of polysaccharides from edible and medicinal mushrooms

BACKGROUND

Despite extensive efforts, empirical techniques have yielded limited progress in finding effective anticancer medications, with chemotherapy drugs often associated with drug resistance and serious side effects. Thus, there is a pressing need for novel agents with minimal adverse effects. Natural substances, widely used in treating various illnesses, including cancer, offer promising alternatives. Among these, mushrooms, rich in low molecular weight secondary metabolites, polysaccharides, and polysaccharide-protein complexes, have gained attention for their potential anticancer properties.

RESULTS

Mushroom polysaccharides have been found to impede oncogenesis and tumor metastasis by directly inhibiting tumor cell growth and indirectly enhancing immune system functions. These polysaccharides engage with numerous cell signaling pathways that influence cancer development and progression. They affect pathways that control cell survival, growth, and differentiation, and they also play a role in adjusting the tumor immune microenvironment.

CONCLUSION

This review highlights the potential of mushroom polysaccharides as promising anticancer agents due to their ability to modulate cell signaling pathways crucial for cancer development. Understanding the mechanisms underlying their effects on these pathways is essential for harnessing their therapeutic potential and developing novel strategies for cancer treatment.

Current Uses of Mushrooms in Cancer Treatment and Their Anticancer Mechanisms

Cancer is the leading cause of mortality worldwide. Various chemotherapeutic drugs have been extensively used for cancer treatment. However, current anticancer drugs cause severe side effects and induce resistance. Therefore, the development of novel and effective anticancer agents with minimal or no side effects is important. Notably, natural compounds have been highlighted as anticancer drugs. Among them, many researchers have focused on mushrooms that have biological activities, including antitumor activity. The aim of this review is to discuss the anticancer potential of different mushrooms and the underlying molecular mechanisms. We provide information regarding the current clinical status and possible modes of molecular actions of various mushrooms and mushroom-derived compounds. This review will help researchers and clinicians in designing evidence-based preclinical and clinical studies to test the anticancer potential of mushrooms and their active compounds in different types of cancers.

Comprehensive review on signaling pathways of dietary saponins in cancer cells suppression

Nutrigenomics utilizes high-throughput genomic technologies to reveal changes in gene and protein levels. Excitingly, ever-growing body of scientific findings has provided sufficient evidence about the interplay between diet and genes. Cutting-edge research and advancements in genomics, epigenetics and metabolomics have deepened our understanding on the role of dietary factors in the inhibition of carcinogenesis and metastasis. Dietary saponins, a type of triterpene glycosides, are generally found in Platycodon grandifloras, Dioscorea oppositifolia, asparagus, legumes, and sea cucumber. Wealth of information has started to shed light on pleiotropic mechanistic roles of dietary saponins in cancer prevention and inhibition. In this review, we have attempted to summarize the in vitro research of dietary saponins in the last two decades by searching common databases such as Google Scholar, PubMed, Scopus, and Web of Science. The results showed that dietary saponins exerted anti-cancer activities via regulation of apoptosis, autophagy, arrest cell cycle, anti-proliferation, anti-metastasis, and anti-angiogenesis, by regulation of several critical signaling pathways, including MAPK, PI3K/Akt/mTOR, NF-κB, and VEGF/VEGFR. However, there is no data about the dosage of dietary saponins for practical anti-cancer effects in human bodies. Extensive clinical studies are needed to confirm the effectiveness of dietary saponins for further commercial and medical applications.

Proteomic Research on the Antitumor Properties of Medicinal Mushrooms

Medicinal mushrooms are increasingly being recognized as an important therapeutic modality in complementary oncology. Until now, more than 800 mushroom species have been known to possess significant pharmacological properties, of which antitumor and immunomodulatory properties have been the most researched. Besides a number of medicinal mushroom preparations being used as dietary supplements and nutraceuticals, several isolates from mushrooms have been used as official antitumor drugs in clinical settings for several decades. Various proteomic approaches allow for the identification of a large number of differentially regulated proteins serendipitously, thereby providing an important platform for a discovery of new potential therapeutic targets and approaches as well as biomarkers of malignant disease. This review is focused on the current state of proteomic research into antitumor mechanisms of some of the most researched medicinal mushroom species, including Phellinus linteus, Ganoderma lucidum, Auricularia auricula, Agrocybe aegerita, Grifola frondosa, and Lentinus edodes, as whole body extracts or various isolates, as well as of complex extract mixtures.

Review on Auricularia auricula-judae as a Functional Food: Growth, Chemical Composition, and Biological Activities

Although the application of Auricularia auricula-judae (AAJ) for health purposes has a long tradition in Asia, there is a lack of research on the functional nutrition of AAJ; the current research focused on polysaccharides has been too unitary compared to other mushrooms in recent years. Identification, extraction, and large-scale production of biologically active substances have emerged as critical determinants that determine AAJ becoming a functional food. AAJ is being treated in a restrained manner, despite having significant potential as a drug or a source of pure bioactive substances. Functional ingredients of mushrooms and AAJ have emerged as a new impetus for researchers interested in developing functional foods. This review presents an overview of current studies relevant to nutrition and the application of AAJ. The physiological conditions of AAJ and the corresponding functional ingredients beneficial to human health are reviewed to better understand the function and mechanisms of different nutrient contents. Relevant methods for evaluating the efficiency of extraction are also summarized. Finally, current limitations and the future scope for functional ingredients of AAJ are identified and discussed.

Significance of Medicinal Mushrooms in Integrative Oncology: A Narrative Review

Medicinal mushrooms are widely used in East Asia for the treatment of various diseases, especially in complementary cancer care. While there is a growing interest in medicinal mushrooms in Western countries and an increasing number of pre-clinical studies indicate distinct anti-cancer and regenerative properties, little is known about their potential relevance for clinical practice. This review aims to provide an overview of the clinical evidence, significance and potential role of medicinal mushrooms in complementary cancer care. Scientific databases for (randomized) controlled clinical trials evaluating whole spectrum formulations of medicinal mushrooms (mushroom powder and mushroom extracts) in cancer patients during and/or after conventional oncological treatment were searched. Eight studies met our inclusion criteria (eight randomized controlled trials, one controlled clinical trial). The medicinal mushrooms investigated were Agaricus sylvaticus (two trials), Agaricus blazei murill (two trials), Antrodia cinnamomea (one trial), Coriolus versicolor (one trial) and Ganoderma lucidum (three trials); all were compared to placebo and administered orally. A variety of cancer entities, outcomes and treatment durations were observed. Study results suggested beneficial effects of medicinal mushrooms, particularly quality of life and reduction of adverse effects of conventional therapies. Also, positive effects on antitumor activity and immunomodulation were reported, e.g., an increased activity of natural killer cells. In addition, results might suggest a longer survival of cancer patients receiving mushroom preparations, although in most studies this was not significant when compared to placebo. Adverse events of treatment with medicinal mushrooms were poorly reported; gastrointestinal reactions and a decrease in platelet cell count occurred in some cases. The methodological quality of most studies was generally unsatisfying and most results were insufficiently reported in several respects. Medicinal mushrooms may have a therapeutic potential for cancer patients during and after conventional oncological care with regards to quality of life, reduction of adverse effects of conventional care and possibly other surrogate parameters like immune function. There is an urgent need to investigate the safety and possible interactions of medicinal mushrooms. High-quality clinical research is warranted in order to clarify the potential of medicinal mushrooms in cancer therapy.

Antitumor, Immunomodulatory and Antiangiogenic Efficacy of Medicinal Mushroom Extract Mixtures in Advanced Colorectal Cancer Animal Model

Due to frequent drug resistance and/or unwanted side-effects during conventional and targeted cancer treatments, development of multi-target therapies is an important research field. Medicinal mushrooms’ isolated specific compounds and mushroom extracts have been already proven as non-toxic multi-target inhibitors of specific oncogenic pathways, as well as potent immunomodulators. However, research on antitumor effects of multiple-species extract mixtures was limited so far. The aim of this study was therefore, a study of medicinal mushroom preparations AGARIKON.1 and AGARIKON PLUS on colorectal cell lines in vitro and colorectal mice model in vivo. We found a significant antiproliferative and pro-apoptotic effect of tested medicinal mushroom preparations on colorectal (HCT-116, SW620) tumor cell lines, while the effect on human fibroblast cell line (WI-38) was proliferative emphasizing a specificity towards tumor cell lines. We further investigated the effect of the medicinal mushroom preparations AGARIKON.1 and AGARIKON PLUS in various combinations with conventional cytostatic drug 5-fluorouracil in the advanced metastatic colorectal cancer mouse model CT26.WT. AGARIKON.1 and AGARIKON PLUS exhibited immunostimulatory and antiangiogenic properties in vivo which resulted in significantly increased survival and reduction in tumor volume. The antitumor effects of AGARIKON.1 and AGARIKON PLUS, with or without 5-fluorouracil, are based on M1 macrophage polarization enhancement, inhibition of M2 and tumor-associated macrophage (TAM) polarization, effects on T helper cell Th1/Th2/Th17 cytokine profiles, direct inhibition of CT26.WT tumor growth, inhibition of vascular endothelial growth factors (VEGF) and metalloproteinases 2 and 9 (MMP-2 and MMP-9) modulation. The administration of AGARIKON.1 and AGARIKON PLUS did not show genotoxic effect. This data provides good basis for an expanded translational study.

The Antiviral, Anti-Inflammatory Effects of Natural Medicinal Herbs and Mushrooms and SARS-CoV-2 Infection

The 2019 novel coronavirus, SARS-CoV-2, producing the disease COVID-19 is a pathogenic virus that targets mostly the human respiratory system and also other organs. SARS-CoV-2 is a new strain that has not been previously identified in humans, however there have been previous outbreaks of different versions of the beta coronavirus including severe acute respiratory syndrome (SARS-CoV1) from 2002 to 2003 and the most recent Middle East respiratory syndrome (MERS-CoV) which was first identified in 2012. All of the above have been recognised as major pathogens that are a great threat to public health and global economies. Currently, no specific treatment for SARS-CoV-2 infection has been identified; however, certain drugs have shown apparent efficacy in viral inhibition of the disease. Natural substances such as herbs and mushrooms have previously demonstrated both great antiviral and anti-inflammatory activity. Thus, the possibilities of natural substances as effective treatments against COVID-19 may seem promising. One of the potential candidates against the SARS-CoV-2 virus may be Inonotus obliquus (IO), also known as chaga mushroom. IO commonly grows in Asia, Europe and North America and is widely used as a raw material in various medical conditions. In this review, we have evaluated the most effective herbs and mushrooms, in terms of the antiviral and anti-inflammatory effects which have been assessed in laboratory conditions.

Treatment With Medicinal Mushroom Extract Mixture Inhibits Translation and Reprograms Metabolism in Advanced Colorectal Cancer Animal Model as Evidenced by Tandem Mass Tags Proteomics Analysis

Colorectal cancer (CRC) is the third most frequent cancer type in both males and females, with about 35% of patients being diagnosed in stage IV metastatic disease. Despite advancements in treatment, life expectancy in patients with metastatic disease is still not satisfying. Due to frequent drug resistance during conventional and targeted cancer treatments, the development and testing of multi-target therapies is an important research field. Medicinal mushrooms specific isolated compounds as well as complex extract mixtures have been studied in depth, and many mushroom species have been proven to be non-toxic multi-target inhibitors of specific oncogenic pathways, as well as potent immunomodulators. In this study, we have performed a tandem mass tags qualitative and quantitative proteomic analyses of CT26.WT colon cancer tumor tissues from Balb/c mice treated with the studied medicinal mushroom extract mixture, with or without 5-fluorouracil. Besides significantly improved survival, obtained results reveal that Agarikon.1 alone, and in combination with 5-fluorouracil exert their anticancer effects by affecting several fundamental processes important in CRC progression. Bioinformatic analysis of up- and downregulated proteins revealed that ribosomal biogenesis and translation is downregulated in treatment groups, while the unfolded protein response (UPR), lipid metabolism and tricarboxylic acid cycle (TCA) are upregulated. Moreover, we found that many known clinical biomarkers and protein clusters important in CRC progression and prognosis are affected, which are a good basis for an expanded translational study of the herein presented treatment.

Wenshen Zhuanggu formula mitigates breast cancer bone metastasis through the signaling crosstalk among the Jagged1/Notch, TGF-β and IL-6 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Advanced breast cancer frequently metastasizes to the bone, resulting in patient morbidity and mortality. The interaction of tumor cells with osteoclasts and osteoblasts seriously affects the occurrence and development of bone metastasis in breast cancer. The signaling crosstalk among the Jagged1/Notch, TGF-β and IL-6 signaling pathways plays a significant role in the context of bone metastasis.

AIM OF THE STUDY

Although Wenshen Zhuanggu (WSZG) formula efficiently decreased the risk of bone metastases in tumor-bearing mice, it remains unclear how WSZG formula regulates the interaction of cancer cells with osteoclasts and osteoblasts in bone metastasis of breast cancer.

MATERIALS AND METHODS

In this study, we investigated the role of WSZG formula in the progress of bone metastasis in breast cancer and focused on the cell-cell interactions of tumor cells with osteoclasts and osteoblasts. Western blotting and quantitative real-time PCR were utilized to evaluate the inhibitory activities of WSZG formula on Jagged1 expression both in vivo and in vitro. Osteoblast co-culture and osteoclastogenesis co-culture were applied to analyze the effects of WSZG formula on the interaction of tumor cells with osteoclasts and osteoblasts. A breast cancer xenograft model was also used to test the inhibitory effects of WSZG formula on bone metastasis in breast cancer.

RESULTS

WSZG formula decreased Jagged1 expression in osteolytic lesions in the breast cancer xenograft model. Additionally, WSZG formula decreased Jagged1 expression in tumor cell culture alone or co-culture with pre-osteoclasts and osteoblasts. In addition, WSZG formula decreased Jagged1 expression in Jagged1-overexpressing tumor cells.

CONCLUSION

The results of this study suggest that WSZG formula mitigates breast cancer bone metastasis through the Jagged1/Notch signaling pathway mediated by TGF-β and IL-6.

Tumor inhibitory effects of intravesical Ganoderma lucidum instillation in the syngeneic orthotopic MB49/C57 bladder cancer mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum (GL) has been traditionally used in oriental medicine as superior health tonic, and there are numerous scientific evidences of its antitumorigenic activities.

AIM OF THE STUDY

To evaluate the intravesical chemopreventive effects of ethanol extract of GL (GLe) on bladder cancer.

MATERIALS AND METHODS

Intravesical therapy is defined as the direct instillation of a liquid drug into bladder through a catheter. Bacille Calmette-Guerin(BCG) solution is applied intravesically as a conventional immunotherapy for preventing recurrence of bladder cancer. By adopting the MB49/C57 bladder cancer mice model, an overall 60 MB49-implanted mice were randomized into 3 groups and treated according to 3 treatment arms, including GLe, BCG and PBS. Additionally, wild-type mice without MB49 cell inoculation and treated with PBS were used as the negative control group. Testing agents were instilled intravesically for 2 h and repeated after one week for evaluating the effects on preventing the tumor formation and growth. The treated-mice were closely monitored for major adverse effects.

RESULTS

GLe demonstrated more potent cytotoxic effects than BCG on MB49 cells, although both in dose-dependent manner. In the MB49-implanted mice, 80 µg/ml GLe was shown to delay the tumor formation by one week, whereas the averaged tumor volume measured at endpoint was 3.6-fold and 4.6-fold smaller than that of the BCG or PBS, respectively. However, no significant effects were observed on body weight and hematuria.

CONCLUSION

Current findings in mice suggested intravesical GLe therapy as an effective and safe chemopreventive strategy for inhibiting bladder tumor formation.