Fungal Immunomodulatory Protein from Nectria haematococca Suppresses Growth of Human Lung Adenocarcinoma by Inhibiting the PI3K/Akt Pathway

An anti-tumor protein PFAP specifically interacts with cholesterol-enriched membrane domains of A549 cells and induces paraptosis and endoplasmic reticulum stress

Nowadays, non-small cell lung cancer (NSCLC) is still one of the most life-threatening diseases in the world. In previous studies, a fungal protein PFAP with anti-NSCLC properties was isolated and identified from Pleurotus ferulae lanzi. In this study, the amino acid sequence of PFAP was analyzed and found to be highly homologous to the aegerolysin family. PFAP, like other members of the aegerolysin family, specifically recognizes lipid raft domains rich in cholesterol and sphingomyelin, which is probably its specific anti-tumor mechanism. Previous studies have shown that PFAP can induce AMPK-mediated autophagy and G1-phase cell cycle arrest in A549 lung cancer cells. This study further revealed that PFAP can also induce paraptosis and endoplasmic reticulum stress (ERS) in A549 cells in vitro by targeting AMPK. PFAP induces multi-pathway death of A549 cells, and thus demonstrates its potential value for developing new drugs for NSCLC.

Ganoderma microsporum immunomodulatory protein combined with KRASG12C inhibitor impedes intracellular AKT/ERK network to suppress lung cancer cells with KRAS mutation

KRAS mutations are tightly associated with lung cancer progression. Despite the unprecedented clinical success of KRASG12C inhibitors, recurrent mechanisms of resistance and other KRAS mutations require further therapeutic approaches. GMI, a protein from the medicinal mushroom Ganoderma microsporum, possesses antitumor activity; whereas, the biological function of GMI on regulating KRAS mutant lung cancer cells remains unknown. Herein, RNA-sequencing and bioinformatics showed that GMI may regulate KRAS-modulated MAPK and PI3K-AKT pathways in A549 (KRASG12S) cells. Further experiments demonstrated that GMI inhibited KRAS activation and suppressed ERK1/2 and AKT signaling in A549 cells. Intriguingly, GMI inhibited AKT signaling but increased phosphorylation of ERK in H358 (KRASG12C) cells. GMI significantly suppressed tumor growth in LLC1 cells-allograft and H358 cells-xenograft mice. GMI showed a synergistic effect with KRASG12C inhibitors in inhibiting cell growth, KRAS activation and KRAS-mediated downstream signaling, leading to apoptosis in H358 cells. Combination of GMI and KRASG12C inhibitor, AMG 510, resulted in more durable inhibition of tumor growth and KRAS activity in H358 cells-xenograft mice. This study highlights the potential of GMI, a dietary fungal protein, as a viable therapeutic avenue for KRAS-mutant lung cancer in combination with KRASG12C inhibitors.

Glycosylation Contributes to Thermostability and Proteolytic Resistance of rFIP-nha (Nectria haematococca)

Glycosylation is an important post-translational modification of proteins, contributing to protein function, stability and subcellular localization. Fungal immunomodulatory proteins (FIPs) are a group of small proteins with notable immunomodulatory activity, some of which are glycoproteins. In this study, the impact of glycosylation on the bioactivity and biochemical characteristics of FIP-nha (from Nectria haematococca) is described. Three rFIP-nha glycan mutants (N5A, N39A, N5+39A) were constructed and expressed in Pichia pastoris to study the functionality of the specific N-glycosylation on amino acid N5 and N39. Their protein characteristics, structure, stability and activity were tested. WT and mutants all formed tetramers, with no obvious difference in crystal structures. Their melting temperatures were 82.2 °C (WT), 81.4 °C (N5A), 80.7 °C (N39A) and 80.1 °C (N5+39A), indicating that glycosylation improves thermostability of rFIP-nha. Digestion assays showed that glycosylation on either site improved pepsin resistance, while 39N-glycosylation was important for trypsin resistance. Based on the 3D structure and analysis of enzyme cleavage sites, we conclude that glycosylation might interfere with hydrolysis via increasing steric hindrance. WT and mutants exerted similar bioactivity on tumor cell metabolism and red blood cells hemagglutination. Taken together, these findings indicate that glycosylation of FIP-nha impacts its thermostability and digestion resistance.

New fungal protein from Pleurotus ferulae lanzi induces AMPK-mediated autophagy and G1-phase cell cycle arrest in A549 lung cancer cells

A new protein, designated PFAP, with activity against non-small cell lung cancer (NSCLC), was isolated from Pleurotus ferulae lanzi, a medicinal and edible mushroom. The purification method involved hydrophobic interaction chromatography on a HiTrap Octyl FF column and gel filtration on a Superdex 75 column. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed a single band with a molecular weight of 14.68 kDa. Following de novo sequencing and liquid chromatography-tandem mass spectrometry, PFAP was identified as a protein consisting of 135 amino acid residues, with a theoretical molecular weight of 14.81 kDa. Tandem mass tag (TMT)™-based quantitative proteomic analysis and western blotting revealed that AMP-activated protein kinase (AMPK) was significantly upregulated in NSCLC A549 cells, following PFAP treatment. The downstream regulatory factor mammalian target of rapamycin (mTOR) was suppressed, resulting in the activation of autophagy and upregulated expressions of P62, LC3 II/I, and other related proteins. PFAP blocked NSCLC A549 cells in the G1 phase of the cell cycle via upregulating P53 and P21, while subsequently downregulating the expression of cyclin-dependent kinases. PFAP suppresses tumour growth via the same mechanism in a xenograft mouse model in vivo. These results demonstrate that PFAP is a multifunctional protein with anti-NSCLC properties.

Characterization, Recombinant Production, and Bioactivity of a Novel Immunomodulatory Protein from Hypsizygus marmoreus

A novel fungal immunomodulatory protein (FIP), identified as FIP-hma, was discovered in the genome of an edible mushroom Hypsizygus marmoreus. Bioinformatics analysis suggested FIP-hma contained the cerato-platanin (CP) conserved domain and was categorized into Cerato-type FIP. In phylogenetic analysis, FIP-hma was clustered into a new branch of the FIP family, displaying large system divergence from most of the other FIPs. The higher gene expression of FIP-hma was observed during the vegetative growth stages than that during the reproductive growth stages. In addition, the cDNA sequence of FIP-hma was cloned and successfully expressed in Escherichia coli (E. coli) BL21(DE3). The recombinant protein of FIP-hma (rFIP-hma) was neatly purified and isolated by Ni-NTA and SUMO-Protease. The iNOS, IL-6, IL-1β, and TNF-α levels of RAW 264.7 macrophages were upregulated by rFIP-hma, indicating its activation of an immune response by regulating central cytokines. No cytotoxic effects were observed in an MTT test. The findings of this work discovered a novel immunoregulatory protein from H. marmoreus, provided a systematic bioinformatic profile, suggested an effective approach for its heterologous recombinant production, and reported its potent immunoregulatory activity in macrophages. This study sheds light on the physiological function research of FIPs and their further industrial utilization.

Platycodin D inhibits HFD/STZ-induced diabetic nephropathy via inflammatory and apoptotic signaling pathways in C57BL/6 mice

ETHNOPHARMACOLOGICAL RELEVANCE

The dried root of Platycodon grandiflorum (Jacq.) A.DC. (PG) is a traditional herb used in Asian countries and is widely used in formulas for the treatment of diabetes. Platycodin D (PD) is one of the most important components of PG.

AIM OF THE STUDY

This study aimed to investigate the improvement effects and regulatory mechanisms of PD on kidney injury in a high-fat diet (HFD) combined with streptozotocin (STZ)-induced diabetic nephropathy (DN).

MATERIALS AND METHODS

Model mice were treated with oral gavage of the PD (2.5, 5 mg/kg) for 8 weeks. Determination of serum lipid and renal function-related indexes creatinine (CRE), and blood urea nitrogen (BUN) levels in mice, and histopathological section analysis of kidney. Molecular docking and molecular dynamics were utilized to study the binding ability of PD to target NF-κB and apoptosis signaling pathway-related proteins. Moreover, western blot was used to test the expressions of NF-κB and apoptosis-related proteins. Vitro experiments were performed to validate the related mechanisms using RAW264.7 cells and HK2 cells cultured by high glucose.

RESULTS

In vivo experiments, the administration of PD (2.5 and 5.0 mg/kg) reduced fasting blood glucose (FBG) and homeostasis model assessment of insulin resistance (HOMA-IR) levels in DN mice, while lipid levels and renal function were significantly improved. Furthermore, PD significantly inhibited the development of DN in the model mice by regulating NF-κB and apoptotic signaling pathways, reduced the abnormal elevation of serum inflammatory factors TNF-α and IL-1β, and repaired renal cell apoptosis. In vitro experiments, NF-κB inhibitor ammonium pyrrolidine dithiocarbamate (PDTC) was used to confirm that PD can alleviate high glucose-induced inflammation in RAW264.7 cells and inhibit the release of inflammatory factors. And in HK2 cell experiments, it was verified that PD can inhibit ROS generation, reduce the loss of JC-1 and suppress HK2 cell injury by regulating NF-κB and apoptotic pathways.

CONCLUSIONS

These data suggested that PD has the potential to prevent and treat DN and is a promising natural nephroprotective agent.

Cystathionine γ-lyase mediates cell proliferation, migration, and invasion of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelia-derived malignancy with a distinctive geographic distribution. Cystathionine γ-lyase (CSE) is involved in cancer development and progression. Nevertheless, the role of CSE in the growth of NPC is unknown. In this study, we found that CSE levels in human NPC cells were higher than those in normal nasopharyngeal cells. CSE overexpression enhanced the proliferative, migrative, and invasive abilities of NPC cells and CSE downregulation exerted reverse effects. Overexpression of CSE decreased the expressions of cytochrome C, cleaved caspase (cas)-3, cleaved cas-9, and cleaved poly-ADP-ribose polymerase, whereas CSE knockdown exhibited reverse effects. CSE overexpression decreased reactive oxygen species (ROS) levels and the expressions of phospho (p)-extracellular signal-regulated protein kinase 1/2, p-c-Jun N-terminal kinase, and p-p38, but promoted the expressions of p-phosphatidylinositol 3-kinase (PI3K), p-AKT, and p-mammalian target of rapamycin (mTOR), whereas CSE knockdown showed oppose effects. In addition, CSE overexpression promoted NPC xenograft tumor growth and CSE knockdown decreased tumor growth by modulating proliferation, angiogenesis, cell cycle, and apoptosis. Furthermore, DL-propargylglycine (an inhibitor of CSE) dose-dependently inhibited NPC cell growth via ROS-mediated mitogen-activated protein kinase (MAPK) and PI3K/AKT/mTOR pathways without significant toxicity. In conclusion, CSE could regulate the growth of NPC cells through ROS-mediated MAPK and PI3K/AKT/mTOR cascades. CSE might be a novel tumor marker for the diagnosis and prognosis of NPC. Novel donors/drugs that inhibit the expression/activity of CSE can be developed in the treatment of NPC.

Cystathionine β-Synthase Regulates the Proliferation, Migration, and Invasion of Thyroid Carcinoma Cells

Thyroid cancer is considered to be one of the most common endocrine tumors worldwide. Cystathionine β-synthase (CBS) plays a crucial role in the occurrence of several types of malignancies. And yet, the mechanism of action of CBS in the growth of thyroid carcinoma cells is still unrevealed. We found that CBS level in thyroid carcinoma tissue was higher than that in adjacent normal tissue. The overexpression of CBS enhanced the proliferation, migration, and invasion of thyroid cancer cells, while the downregulation of CBS exerted reverse effects. CBS overexpression reduced the levels of cleaved caspase-3 and cleaved poly ADP-ribose polymerase in thyroid cancer cells, whereas CBS knockdown showed reverse trends. CBS overexpression decreased reactive oxygen species (ROS) levels but increased the levels of Wnt3a and phosphorylations of phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB/AKT), mammalian target of rapamycin (mTOR), β-catenin, and glycogen synthase kinase-3 beta, while CBS knockdown exerted opposite effects. In addition, CBS overexpression promoted the growth of xenografted thyroid carcinoma, whereas CBS knockdown decreased the tumor growth by modulating angiogenesis, cell cycle, and apoptosis. Furthermore, aminooxyacetic acid (an inhibitor of CBS) dose-dependently inhibited thyroid carcinoma cell growth. CBS can regulate the proliferation, migration, and invasion of human thyroid cancer cells via ROS-mediated PI3K/AKT/mTOR and Wnt/β-catenin pathways. CBS can be a potential biomarker for diagnosing or prognosing thyroid carcinoma. Novel donors that inhibit the expression of CBS can be developed in the treatment of thyroid carcinoma.

FIP-nha, a fungal immunomodulatory protein from Nectria haematococca, induces apoptosis and autophagy in human gastric cancer cells via blocking the EGFR-mediated STAT3/Akt signaling pathway

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FIP-nha, a new FIP discovered beyond Basidiomycota, has been demonstrated a broad spectrum of antitumor activity and cell selectivity against human cancers.

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FIP-nha inhibited the growth, induced apoptosis and autophagy of gastric cancer cells through competitively binding to EGFR with EGF to blocking the EGFR-mediated STAT3/Akt pathway.

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FIP-nha may be a potential chemotherapy drug that targeted EGFR to treat human gastric cancer.

FIP-nha, a fungal immunomodulatory protein from Nectria haematococca, has been demonstrated a broad spectrum of antitumor activity and cell selectivity against human cancers in our previous study. However, the effect and mechanism of FIP-nha on gastric cancer remains unclear. In this study, we systematically observed the cytotoxicity, biological effect, regulatory mechanism and interaction target of FIP-nha on human gastric cancer cell lines, AGS and SGC7901. Our results demonstrated that FIP-nha inhibited the growth of AGS and SGC7901 cells in a dose-dependent manner and exerted proapoptotic effects on both cells as confirmed by flow cytometry, DAPI staining and western blot analysis. Additionally, the exposure of AGS and SGC7901 to FIP-nha induced autophagy as indicated by western blot analysis, GFP-LC3 and mCherry-GFP-LC3 transfection and acridine orange staining. Furthermore, we found that FIP-nha decreased the phosphorylation of EGFR, STAT3 and Akt and inhibited activation effect of ligand factor EGF to EGFR and its downstream signal molecule STAT3 and Akt. Finally, we proved that FIP-nha located on the surface of gastric cancer cells and bound directly to the transmembrane protein of EGFR by immunoprecipitation, cellular localization, molecular docking, microscale thermophoresis assay. The above findings indicated that FIP-nha inhibited the growth of gastric cancer and induced apoptosis and autophagy through competitively binding to EGFR with EGF to blocking the EGFR-mediated STAT3/Akt pathway. In summary, our study provided novel insights regarding the activity of FIP-nha against gastric cancer and contributed to the clinical application of FIP-nha as a potential chemotherapy drugs that targeted EGFR for human gastric cancer.

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.

Protective Activity of Aspirin Eugenol Ester on Paraquat-Induced Cell Damage in SH-SY5Y Cells

Aspirin eugenol ester (AEE) is a new pharmaceutical compound esterified by aspirin and eugenol, which has anti-inflammatory, antioxidant, and other pharmacological activities. The aim of this study was to investigate the protective effect of AEE on paraquat- (PQ-) induced cell damage of SH-SY5Y human neuroblastoma cells and its potential molecular mechanism. There was no significant change in cell viability when AEE was used alone. PQ treatment reduced cell viability in a concentration-dependent manner. However, AEE reduced the PQ-induced loss of cell viability. Flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and 4′6-diamidino-2-phenylindole (DAPI) staining were used to evaluate cell apoptosis. Compared with the PQ group, AEE pretreatment could significantly inhibit PQ-induced cell damage. AEE pretreatment could reduce the cell damage of SH-SY5Y cells induced by PQ via reducing superoxide anion, intracellular reactive oxygen species (ROS), and mitochondrial ROS (mtROS) and increasing the levels of mitochondrial membrane potential (ΔΨm). At the same time, AEE could increase the activity of glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) and decrease the activity of malondialdehyde (MDA). The results showed that compared with the control group, the expression of p-PI3K, p-Akt, and Bcl-2 was significantly decreased, while the expression of caspase-3 and Bax was significantly increased in the PQ group. In the AEE group, AEE pretreatment could upregulate the expression of p-PI3K, p-Akt, and Bcl-2 and downregulate the expression of caspase-3 and Bax in SH-SY5Y cells. PI3K inhibitor LY294002 and the silencing of PI3K by shRNA could weaken the protective effect of AEE on PQ-induced SH-SY5Y cells. Therefore, AEE has a protective effect on PQ-induced SH-SY5Y cells by regulating the PI3K/Akt signal pathway to inhibit oxidative stress.

Mycopharmaceuticals and Nutraceuticals: Promising Agents to Improve Human Well-Being and Life Quality

Fungi, especially edible mushrooms, are considered as high-quality food with nutritive and functional values. They are of considerable interest and have been used in the synthesis of nutraceutical supplements due to their medicinal properties and economic significance. Specific fungal groups, including predominantly filamentous endophytic fungi from Ascomycete phylum and several Basidiomycetes, produce secondary metabolites (SMs) with bioactive properties that are involved in the antimicrobial and antioxidant activities. These beneficial fungi, while high in protein and important fat contents, are also a great source of several minerals and vitamins, in particular B vitamins that play important roles in carbohydrate and fat metabolism and the maintenance of the nervous system. This review article will summarize and discuss the abilities of fungi to produce antioxidant, anticancer, antiobesity, and antidiabetic molecules while also reviewing the evidence from the last decade on the importance of research in fungi related products with direct and indirect impact on human health.

Epigallocatechin-3-Gallate Alleviates High-Fat Diet-Induced Nonalcoholic Fatty Liver Disease via Inhibition of Apoptosis and Promotion of Autophagy through the ROS/MAPK Signaling Pathway

Nonalcoholic fatty liver disease (NAFLD) represents one of the most common chronic liver diseases in the world. It has been reported that epigallocatechin-3-gallate (EGCG) plays important biological and pharmacological roles in mammalian cells. Nevertheless, the mechanism underlying the beneficial effect of EGCG on the progression of NAFLD has not been fully elucidated. In the present study, the mechanisms of action of EGCG on the growth, apoptosis, and autophagy were examined using oleic acid- (OA-) treated liver cells and the high-fat diet- (HFD-) induced NAFLD mouse model. Administration of EGCG promoted the growth of OA-treated liver cells. EGCG could reduce mitochondrial-dependent apoptosis and increase autophagy possibly via the reactive oxygen species- (ROS-) mediated mitogen-activated protein kinase (MAPK) pathway in OA-treated liver cells. In line with in vitro findings, our in vivo study verified that treatment with EGCG attenuated HFD-induced NAFLD through reduction of apoptosis and promotion of autophagy. EGCG can alleviate HFD-induced NAFLD possibly by decreasing apoptosis and increasing autophagy via the ROS/MAPK pathway. EGCG may be a promising agent for the treatment of NAFLD.

LC-MS/MS-Based Quantitative Proteomics Analysis of Different Stages of Non-Small-Cell Lung Cancer

Lung cancer has a higher incidence rate and mortality rate than all other cancers. Early diagnosis and treatment of lung cancer remain a major challenge, and the 5-year survival rate of its patients is only 15%. Basic and clinical research, especially the discovery of biomarkers, is crucial for improving the diagnosis and treatment of lung cancer patients. To identify novel biomarkers for lung cancer, we used the iTRAQ8-plex labeling technology combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze the serum and urine of patients with different stages of lung adenocarcinoma and healthy individuals. A total of 441 proteins were identified in the serum, and 1,161 proteins were identified in the urine. The levels of elongation factor 1-alpha 2, proteasome subunit alpha type, and spermatogenesis-associated protein increased significantly in the serum of patients with lung cancer compared with those in healthy controls. The levels of transmembrane protein 143, cadherin 5, fibronectin 1, and collectin-11 decreased significantly in the serum of patients with metastases compared with those of nonmetastatic lung cancer patients. In the urine of stage III and IV lung cancer patients, the prostate-specific antigen and prostatic acid phosphatase decreased significantly, whereas neutrophil defensin 1 increased significantly. The results of LC-MS/MS were confirmed by enzyme-linked immunosorbent assay (ELISA) for transmembrane protein 143, cadherin 5, fibronectin 1, and collectin-11 in the serum. These proteins may be a potential early diagnosis and metastasis biomarkers for lung adenocarcinoma. Furthermore, the relative content of these markers in the serum and urine could be used to determine the progression of lung adenocarcinoma and achieve accurate staging and diagnosis.

Exploring the five different genes associated with PKCα in bladder cancer based on gene expression microarray

Much progress has been made in understanding the mechanism of bladder cancer (BC) progression. Protein kinase C‐α (PKCα) is overexpressed in many kinds of cancers. Additionally, PKCα is considered an oncogene that regulates proliferation, invasion, migration, apoptosis and cell cycle in multiple cancers. However, the mechanism underlying how these cellular processes are regulated by PKCα remains unknown. In the present study, we used PKCα siRNA to knock down PKCα gene expression and found that down‐regulation of PKCα could significantly inhibit cell proliferation, migration and invasion and induce apoptosis and G1/S cell cycle arrest in vitro. Overexpression of PKCα promotes tumour growth in vivo. We applied cDNA microarray technology to detect the differential gene expression in J82 cells with PKCα knockdown and found that five key genes (BIRC2, BIRC3, CDK4, TRAF1 and BMP4) were involved in proliferation and apoptosis according to GO analysis and pathway analyses. Correlation analysis revealed a moderate positive correlation between PKCα expression and the expression of five downstream genes. BIRC2 and BIRC3 inhibit apoptosis, whereas CDK4, TRAF1 and BMP4 promote proliferation. Essentially, all five of these target genes participated in proliferation, and apoptosis was regulated by PKCα via the NF‐kB signalling pathway.

New advances and potentials of fungal immunomodulatory proteins for therapeutic purposes

Fungal immunomodulatory proteins (FIPs) are fascinating small and heat-stable bioactive proteins in a distinct protein family due to similarities in their structures and sequences. They are found in fungi, including the fruiting bodies producing fungi comprised of culinary and medicinal mushrooms. Structurally, most FIPs exist as homodimers; each subunit consisting of an N-terminal α-helix dimerization and a C-terminal fibronectin III domain. Increasing numbers of identified FIPs from either different or same fungal species clearly indicates the growing research interests into its medicinal properties which include immunomodulatory, anti-inflammation, anti-allergy, and anticancer. Most FIPs increased IFN-γ production in peripheral blood mononuclear cells, potentially exerting immunomodulatory and anti-inflammatory effects by inhibiting overproduction of T helper-2 (Th2) cytokines common in an allergy reaction. Recently, FIP from Ganoderma microsporum (FIP-gmi) was shown to promote neurite outgrowth for potential therapeutic applications in neuro-disorders. This review discussed FIPs' structural and protein characteristics, their recombinant protein production for functional studies, and the recent advances in their development and applications as pharmaceutics and functional foods.

Current Understanding of the Structure and Function of Fungal Immunomodulatory Proteins

Fungal immunomodulatory proteins (FIPs) are a group of proteins found in fungi, which are extensively studied for their immunomodulatory activity. Currently, more than 38 types of FIPs have been described. Based on their conserved structure and protein identity, FIPs can be classified into five subgroups: Fve-type FIPs (Pfam PF09259), Cerato-type FIPs (Pfam PF07249), PCP-like FIPs, TFP-like FIPs, and unclassified FIPs. Among the five subgroups, Fve-type FIPs are the most studied for their hemagglutinating, immunomodulating, and anti-cancer properties. In general, these small proteins consist of 110–125 amino acids, with a molecular weight of ~13 kDa. The other four subgroups are relatively less studied, but also show a noticeable influence on immune cells. In this review, we summarized the protein modifications, 3-dimensional structures and bioactivities of all types of FIPs. Moreover, structure-function relationship of FIPs has been discussed, including relationship between carbohydrate binding module and hemagglutination, correlation of oligomerization and cytokine induction, relevance of glycosylation and lymphocyte activation. This summary and discussion may help gain comprehensive understanding of FIPs' working mechanisms and scope future studies.

Immunomodulatory Protein from Nectria haematococca Induces Apoptosis in Lung Cancer Cells via the P53 Pathway

Our previous research has shown that a fungal immunomodulatory protein from Nectria haematococca (FIP-nha) possesses a wide spectrum of anti-tumor activities, and FIP-nha induced A549 apoptosis by negatively regulating the PI3K/Akt signaling pathway based on comparative quantitative proteomics. This study further confirmed that the anti-lung cancer activity of FIP-nha was significantly stronger than that of the reported LZ-8 and FIP-fve. Subsequently, ¹H NMR-based metabolomics was applied to comprehensively investigate the underlying mechanism, and a clear separation of FIP-nha-treated and untreated groups was achieved using pattern recognition analysis. Four potential pathways associated with the anti-tumor effect of FIP-nha on A549 cells were identified, and these were mainly involved in glycolysis, taurine and hypotaurine metabolism, fructose and mannose metabolism, and glycerolipid metabolism. Metabolic pathway analysis demonstrated that FIP-nha could induce A549 cell apoptosis partly by regulating the p53 inhibition pathway, which then disrupted the Warburg effect, as well as through other metabolic pathways. Using RT-PCR analysis, FIP-nha-induced apoptosis was confirmed to occur through upregulation of p53 expression. This work highlights the possible use of FIP-nha as a therapeutic adjuvant for lung cancer treatment.