Ganoderma microsporum immunomodulatory protein induces apoptosis and potentiates mitomycin C‐induced apoptosis in urinary bladder urothelial carcinoma cells

Ganoderma immunomodulatory proteins: mushrooming functional FIPs

Fungal immunomodulatory protein (FIP) is a novel functional protein family with specific immunomodulatory activity identified from several macro-fungi. A variety of biological activities of FIPs have been reported, such as anti-allergy, anti-tumor, mitogenic activity, and immunomodulation. Among all known FIPs, the firstly discovered FIP was isolated from Ganoderma lucidum, and most FIP members were from Ganoderma genus. Compared with other FIPs, Ganoderma FIPs possess some advantageous bioactivities, like stronger anti-tumor activity. Therein, gene sequences, protein structural features, biofunctions, and recombinant expression of Ganoderma FIPs were summarized and addressed, focusing on elucidating their anti-tumor activity and molecular mechanisms. Combined with current advances, development potential and application of Ganoderma FIPs were also prospected. KEY POINTS: • More than a dozen of reported FIPs are identified from Ganoderma species. • Ganoderma immunomodulatory proteins have superior anti-tumor activity with promising prospects and application. • Current review comprehensively addresses characterization, biofunctions, and anti-tumor mechanisms of Ganoderma FIPs.

Ganoderma microsporum immunomodulatory protein, GMI, promotes C2C12 myoblast differentiation in vitro via upregulation of Tid1 and STAT3 acetylation

Ageing and chronic diseases lead to muscle loss and impair the regeneration of skeletal muscle. Thus, it’s crucial to seek for effective intervention to improve the muscle regeneration. Tid1, a mitochondrial co-chaperone, is important to maintain mitochondrial membrane potential and ATP synthesis. Previously, we demonstrated that mice with skeletal muscular specific Tid1 deficiency displayed muscular dystrophy and postnatal lethality. Tid1 can interact with STAT3 protein, which also plays an important role during myogenesis. In this study, we used GMI, immunomodulatory protein of Ganoderma microsporum, as an inducer in C2C12 myoblast differentiation. We observed that GMI pretreatment promoted the myogenic differentiation of C2C12 myoblasts. We also showed that the upregulation of mitochondria protein Tid1 with the GMI pre-treatment promoted myogenic differentiation ability of C2C12 cells. Strikingly, we observed the concomitant elevation of STAT3 acetylation (Ac-STAT3) during C2C12 myogenesis. Our study suggests that GMI promotes the myogenic differentiation through the activation of Tid1 and Ac-STAT3.

Functional proteomic analysis reveals that fungal immunomodulatory protein reduced expressions of heat shock proteins correlates to apoptosis in lung cancer cells

BACKGROUND

Ling Zhi-8 (LZ-8) and GMI are two fungal immunomodulatory proteins (FIPs) with a similar structure and amino acid sequence and are respectively obtained from the medicinal mushroom Ganoderma lucidum and Ganoderma microsporum. They present the anti-cancer progression and metastasis. We previously demonstrated that LZ-8 reduces the tumor progression in lung cancer LLC1 cell-bearing mouse. However, it is unclear whether these FIPs induce changes in the protein expression profile in cancer cells and the mechanism for such a process is not defined.

PURPOSE

This study determines the changes in the proteomic profile for tumor lesions of LLC1 cell-bearing mouse received with LZ-8 and the potential mechanism for FIPs in anti-lung cancer cells.

METHODS

The proteomic profile of tumor lesions was determined using two-dimensional electrophoresis and a LTQ-OrbitrapXL mass spectrometer (LC-MS/MS). The biological processes and the signaling pathway enrichment analysis were performed using Ingenuity Pathway Analysis (IPA). The differentially expressed proteins were verified by Western blot. Cell viability was determined by MTT assay. Cell morphology was characterized using electron microscopy. Migration was detected using the Transwell assay. The apoptotic response was determined using Western blot and flow cytometry.

RESULTS

Obtained results showed that 21 proteins in the tumor lesions exhibited differential (2-fold change, p < 0.05) expression between PBS and LZ-8 treatment groups. LZ-8-induced changes in the proteomic profile that may relate to protein degradation pathways. Specifically, three heat shock proteins (HSPs), HSP60, 70 and 90, were significantly downregulated in tumor lesions of LLC1-bearing mouse received with LZ-8. Both LZ-8 and GMI reduced the protein levels for these HSPs in lung cancer cells. Functional studies showed that they inhibited cell migration but effectively induced apoptotic response in LLC1 cells in vitro. In addition, the inhibitors of HSP60 and HSP70 effectively inhibited cell migration and decreased cell viability of LLC1 cells.

CONCLUSIONS

LZ-8 induced changes in the proteomic profile of tumor lesions which may regulate the HSPs-related cell viability. Moreover, inhibition of HSPs may be related to the anti-lung cancer activity.

Combination treatment of Src inhibitor Saracatinib with GMI, a Ganoderma microsporum immunomodulatory protein, induce synthetic lethality via autophagy and apoptosis in lung cancer cells

Saracatinib is an oral Src-kinase inhibitor and has been studied in preclinical models and clinical trials of cancer therapy. GMI, a fungal immunomodulatory protein from Ganoderma microsporum, possesses antitumor capacity. The aim of this study is to evaluate the cytotoxic effect of combination treatment with saracatinib and GMI on parental and pemetrexed-resistant lung cancer cells. Cotreatment with saracatinib and GMI induced synergistic and additive cytotoxic effect in A549 and A400 cells by annexin V/propidium iodide assay and combination index. Using western blot assay, saracatinib, and GMI combined treatment synergistically induced caspase-7 activation in A549 cells. Different from A549 cells, saracatinib and GMI cotreatment markedly increased LC3B-II in A400 cells. ATG5 silencing abolished the caspase-7 activation and reduced cell death in A549 cells after cotreatment. This is the first study to provide a novel strategy of treating lung cancer with or without drug resistance via combination treatment with GMI and saracatinib.

CD133 inhibition via autophagic degradation in pemetrexed-resistant lung cancer cells by GMI, a fungal immunomodulatory protein from Ganoderma microsporum

Background

Adaptive drug resistance is an unfavourable prognostic factor in cancer therapy. Pemetrexed-resistant lung cancer cells possess high-metastatic ability via ERK–ZEB1 pathway-activated epithelial–mesenchymal transition. GMI is a fungal immunomodulatory protein that suppresses the survival of several cancer cells.

Methods

Cell viability was analysed by MTT, clonogenic, tumour spheroid, and cancer stem cell sphere assays. Western blot assay was performed to detect the protein expression. Chemical inhibitors and ATG5 shRNA were used to inhibit autophagy. Tumour growth was investigated using xenograft mouse model.

Results

GMI decreased the viability with short- and long-term effects and induced autophagy but not apoptosis in A549/A400 cells. GMI downregulated the expression levels of CD133, CD44, NANOG and OCT4. GMI induces the protein degradation of CD133 via autophagy. CD133 silencing decreased the survival and proliferation of A549/A400 cells. GMI suppressed the growth and CD133 expression of A549/A400 xenograft tumour.

Conclusions

This study is the first to reveal the novel function of GMI in eliciting cytotoxic effect and inhibiting CD133 expression in pemetrexed-resistant lung cancer cells via autophagy. Our finding provides evidence that CD133 is a potential target for cancer therapy.

Inhibiting TrxR suppresses liver cancer by inducing apoptosis and eliciting potent antitumor immunity

Liver cancer is one of the most common malignant tumors worldwide. Thioredoxin reductase (TrxR) is highly expressed in liver cancer cells. The present study aimed to investigate the effect of inhibiting TrxR on liver cancer and to better understand the underlying molecular and immuno-logical mechanisms associated with inhibition. It was demonstrated that targeting TrxR inhibited the growth and induced apoptosis of liver cancer cells, which was accompanied by activation of the mitogen associated protein kinase pathway. This inhibition was dependent on the production of reactive oxygen species (ROS). Blockage of ROS production reversed TrxR inhibitor‑induced antitumor effects. Blocking the Trx/TrxR system activated the mammalian target of rapamycin pathway and inhibited autophagy, which occurred in a ROS‑independent manner. TrxR inhibition led to lesions in the mitochondrial membrane, indicated by alterations in membrane potential. Mouse xenograft experiments were highly consistent with in vitro studies. Most importantly, blocking the Trx/TrxR system improved the tumor immune microenvironment. Together, these data demonstrated that TrxR is a potential target for liver cancer therapy, which could inhibit hepatocarcinogenesis and progression, and improve the antitumor immune response.

GMI, a fungal immunomodulatory protein from Ganoderma microsporum, induce apoptosis via β-catenin suppression in lung cancer cells

β-catenin is important in development of lung cancer. In our previous study, GMI, a fungal immunomodulatory protein, inhibits lung cancer cell survival. The aim of this study is to evaluate the effect of GMI on β-catenin inhibition and apoptosis induction. GMI induced apoptosis in lung cancer cells bearing wild-type and mutated EGFR. GMI did not reduce the β-catenin mRNA expression but suppressed the protein expressions of β-catenin that resulted in the transcriptional downregulation of its target genes: survivin and cyclin-D1. The transcriptional activation activity of β-catenin was demonstrated by TOPFLASH/FOPFLASH luciferase reporter assay. Inhibition of GSK-3β and proteasome blocked the inhibiting effect of GMI on β-catenin and its target genes. β-catenin silencing increased activation of apoptosis in GMI-treated H1355 cells. This is the first study to reveal the novel function of GMI in inducing apoptosis via β-catenin inhibition. These results provide a new potential of GMI in against lung cancer.