The differential immunological activities of Ganoderma lucidum on human pre-cancerous uroepithelial cells

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.

Ethanol Extract of Ganoderma lucidum Augments Cellular Anti-oxidant Defense through Activation of Nrf2/HO-1

Objectives:

The mushroom Ganoderma lucidum has been widely used as a traditional herbal medicine for many years. Although several studies have focused on the anti-oxidative activity of this mushroom, the molecular mechanisms underlying its activity have not yet been clearly established. The present study investigated the cytoprotective effect of ethanol extract of Ganoderma lucidum (EGL) against oxidative stress (hydrogen peroxide, H₂O₂) and elucidated the underlying mechanisms in a C2C12 myoblast cell line.

Methods:

Oxidative stress markers were determined by using the comet assay to measure reactive oxygen species (ROS) generation and deoxyribonucleic acid (DNA) damage. Cell viability and Western blotting analyses were employed to evaluate the cellular response to EGL and H₂O₂ in C2C12 cells. Transfection with nuclear factor erythroid 2-related factor 2 (Nrf2)-specific small interfering ribonucleic acid (siRNA) was conducted to understand the relationship between Nrf2 expression and H₂O₂-induced growth inhibition.

Results:

The results showed that EGL effectively inhibited H₂O₂-induced growth and the generation of ROS. EGL markedly suppressed H₂O₂-induced comet-like DNA formation and phosphorylation of histone H2AX at serine 139 (p-γH2AX), a widely used marker of DNA damage, suggesting that EGL prevented H₂O₂-induced DNA damage. Furthermore, the EGL treatment effectively induced the expression of Nrf2, as well as heme oxygenase-1 (HO-1), with parallel phosphorylation and nuclear translocation of Nrf2 in the C2C12 myoblasts. However, zinc protoporphyrin IX, a HO-1 inhibitor, significantly abolished the protective effects of EGL against H₂O₂-induced accumulation of ROS and reduced cell growth. Notably, transient transfection with Nrf2-specific siRNA attenuated the cytoprotective effects and HO-1 induction by EGL, indicating that EGL induced the expression of HO-1 in an Nrf2-dependent manner.

Conclusion:

Collectively, these results demonstrate that EGL augments the cellular anti-oxidant defense capacity through activation of Nrf2/HO-1, thereby protecting C2C12 myoblasts from H₂O₂-induced oxidative cytotoxicity.

Synergistic Cytotoxic Effects of Ganoderma lucidum and Bacillus Calmette Guérin on Premalignant Urothelial HUC-PC Cells and Its Regulation on Proinflammatory Cytokine Secretion

Bacillus Calmette-Guérin (BCG) is conventionally used as an adjuvant immunotherapy to reduce the recurrence of bladder cancer. To address the issues of efficacy and safety, an ethanol extract of Ganoderma lucidum (GLe) was evaluated for its interaction with BCG. In a model of premalignant human uroepithelial cells (HUC-PC), GLe exerted immediate cytotoxic effects while BCG showed a delayed response, given that both were immunological active in inducing the secretion of interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1 (MCP-1). Synergistic cytotoxic effects were observed when cells were either coincubated with both drugs or firstly preincubated with GLe. Synergism between GLe and BCG was demonstrated to achieve a complete cytostasis in 24 hours, and such effects were progressed in the subsequent 5 days. However, the pretreatment of GLe resulted in suppression of IL-6, IL-8, and MCP-1 secretions without affecting the cytotoxicity. Given that numerous proinflammatory cytokines are associated with the high side effects toll of BCG, results herein suggested the potential implications of GL to supplement the BCG immunotherapy in bladder cancer, for better efficacy and reducing side effects.

Apoptotic and Immune Restoration Effects of Ganoderic Acids Define a New Prospective for Complementary Treatment of Cancer

Considering the fact that a key factor in tumor development is the evasion of immune detection, the search for natural products, which have reduced toxicity towards normal tissues as well as immunostimulatory capabilities has received growing interest. One attractive source of antitumor products is the Ganoderma lucidum mushroom, which has been used for centuries as an herbal medicine for the prevention and treatment of a variety of diseases, including cancer, and has been shown to improve immune function. Interestingly, its methanol soluble triterpenoid extracts, namely Ganoderic Acids (GAs), have been the subject of several recent investigations on their chemotherapeutic effects. While current research has revealed GAs' role in inducing apoptosis of cancer cells with a much lower toxicity to healthy cells, little information is available on their in vitro and/or in vivo immune activities. In this review, we aim to discuss the current knowledge on GAs, and their potential as apoptosis inducing as well as immune activating molecules that could be a potential alternative approach for designing novel chemoimmunotherapeutics against malignant diseases. We also discuss other new approaches for exploiting the advantages of using a nanoparticle polymer-GA conjugate as a tool for a sustained and targeted delivery of drug in vivo.