AKT signalling and mitochondrial pathways are involved in mushroom polysaccharide-induced apoptosis and G1 or S phase arrest in human hepatoma cells

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.

Anti-liver cancer effects and mechanisms and its application in nano DDS of polysaccharides: A review

Liver cancer is the third leading cause of cancer death, with high incidence and poor treatment effect. In recent years, polysaccharides have attracted more and more attention in the research field of anti-liver cancer because of their high efficiency, low toxicity, good biocompatibility, wide sources and low cost. Polysaccharides have been proven to have good anti-liver cancer activity. In this paper, the pathways and molecular mechanisms of polysaccharides against liver cancer were reviewed in detail. Polysaccharides exert anti-liver cancer activity by blocking cell cycle, inducing apoptosis, regulating immunity, inhibiting cancer cell metastasis, inhibiting tumor angiogenesis and so on. The primary structure and chain conformation of polysaccharides have an important influence on their anti-liver cancer activity. Structural modification enhanced the anti-liver cancer activity of polysaccharides. Polysaccharides have good attenuated and synergistic effects on chemotherapy drugs. Polysaccharides can be used as functional carriers to construct intelligent nano drug delivery systems (DDS) targeting liver cancer. This review can provide theoretical support for the further development and application of polysaccharides in the field of anti-liver cancer, and provide theoretical reference and clues for relevant researchers in food, nutrition, medicine and other fields.

A review for cancer treatment with mushroom metabolites through targeting mitochondrial signaling pathway: In vitro and in vivo evaluations, clinical studies and future prospects for mycomedicine

Resistance to apoptosis stands as a roadblock to the successful pharmacological execution of anticancer drug effect. A comprehensive insight into apoptotic signaling pathways and an understanding of the mechanisms of apoptosis resistance are crucial to unveil new drug targets. At this juncture, researchers are heading towards natural sources in particular, mushroom as their potential drugs leads to being the reliable source of potent bioactive compounds. Given the continuous increase in cancer cases, the potent anticancer efficacy of mushrooms has inevitably become a fascinating object to researchers due to their higher safety margin and multitarget. This review aimed to collect and summarize all the available scientific data on mushrooms from their extracts to bioactive molecules in order to suggest their anticancer attributes via a mitochondrion -mediated intrinsic signaling mechanism. Compiled data revealed that bioactive components of mushrooms including polysaccharides, sterols and terpenoids as well as extracts prepared using 15 different solvents from 53 species could be effective in the supportive treatment of 20 various cancers. The underlying therapeutic mechanisms of the studied mushrooms are explored in this review through diverse and complementary investigations: in vitro assays, pre-clinical studies and clinical randomized controlled trials. The processes mainly involved were ROS production, mitochondrial membrane dysfunction, and action of caspase 3, caspase 9, XIAP, cIAP, p53, Bax, and Bcl-2. In summary, the study provides facts pertaining to the potential beneficial effect of mushroom extracts and their active compounds against various types of cancer and is shedding light on the underlying targeted signaling pathways.

Insights into the Chemical Compositions and Health Promoting Effects of Wild Edible Mushroom Chroogomphus rutilus

Chroogomphus rutilus is an edible mushroom that has been an important food source since ancient times. It is increasingly sought after for its unique flavor and medicinal value. It is one of the most important wild mushrooms for its medicinal and economic value. C. rutilus contains a variety of active ingredients such as vitamins, proteins, minerals, polysaccharides, and phenolics. C. rutilus and its active compounds have significant anti-oxidant, anti-tumor, immunomodulatory, anti-fatigue, hypoglycemic, gastroprotective, hypolipemic, and neuronal protective properties. This paper summarizes the fungal chemical compositions and health-promoting effects of C. rutilus by collecting the literature on the role of C. rutilus through its active ingredients from websites such as Google Scholar, Scopus, PubMed, and Web of Science. Current research on C. rutilus is limited to the cellular and animal levels, and further clinical trials are needed to conduct and provide theoretical support for further development.

Suppressive effects of bioactive herbal polysaccharides against different cancers: From mechanisms to translational advancements

BACKGROUND

Fueled by rapidly evolving comprehension of multifaceted nature of cancers, recently emerging preclinical and clinical data have supported researchers in the resolution of knowledge gaps to deepen the understanding of the molecular mechanisms. The extra-ordinary and bewildering chemical diversity encompassed by biologically active natural products continues to be of relevance to drug discovery. Accumulating evidence has spurred a remarkable evolution of concepts related to pharmacological target of oncogenic signaling pathways by polysaccharides in different cancers.

PURPOSE

The objective of the current review is to provide new insights into study progress on anticancer effects of bioactive herbal polysaccharides.

METHODS

PubMed, Scopus, Web of Science, Embase, and other databases were searched for articles related to anticancer effects of polysaccharides. Searches were conducted to locate relevant publications published up to October 2022.

RESULTS

Polysaccharides have been reported to pleiotropically modulate TGF/SMAD, BMP/SMAD, TLR4, mTOR, CXCR4 and VEGF/VEGFR cascades. We have also summarized how different polysaccharides regulated apoptosis and non-coding RNAs. Additionally, this mini-review describes increasingly sophisticated understanding related to polysaccharides mediated tumor suppressive and anti-metastatic effects in tumor-bearing mice. We have also provided an overview of the clinical trials related to chemopreventive role of polysaccharides.

CONCLUSION

Genomic and proteomic findings from these studies will facilitate 'next-generation' clinical initiatives in the prevention/inhibition of cancer.

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.

Mushroom Polysaccharide-Assisted Anticarcinogenic Mycotherapy: Reviewing Its Clinical Trials

Of the biologically active components, polysaccharides play a crucial role of high medical and pharmaceutical significance. Mushrooms have existed for a long time, dating back to the time of the Ancient Egypt and continue to be well explored globally and experimented with in research as well as in national and international cuisines. Mushroom polysaccharides have slowly become valuable sources of nutraceuticals which have been able to treat various diseases and disorders in humans. The application of mushroom polysaccharides for anticancer mycotherapy is what is being reviewed herein. The widespread health benefits of mushroom polysaccharides have been highlighted and the significant inputs of mushroom-based polysaccharides in anticancer clinical trials have been presented. The challenges and limitation of mushroom polysaccharides into this application and the gaps in the current application areas that could be the future direction have been discussed.

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.

Induction of Apoptosis in HeLa Cells by a Novel Peptide from Fruiting Bodies of Morchella importuna via the Mitochondrial Apoptotic Pathway

Morels (Morchella spp.) are a genus of edible fungi with important economic and medicinal value. In this study, a novel peptide (MIPP) was extracted from the fruiting bodies of Morchella importuna using gel filtration chromatography. Structural analysis showed that the molecular mass of MIPP is 831 Da, and it has a simple amino acid sequence: Ser-Leu-Ser-Leu-Ser-Val-Ala-Arg. To explore the antitumor activity of MIPP, the effect of MIPP on HeLa cell apoptosis and the underlying preventative mechanisms were investigated. Results showed that MIPP reduced the viability of HeLa cells in a concentration-dependent manner. TUNEL analysis and flow cytometric examination showed that MIPP decreased cell proliferation via a mitochondrial-dependent pathway, as manifested by downregulation of Bcl-2/Bax, promotion of the movement of cytochrome C from the mitochondria to the cytoplasm, and triggering of caspase-9 and caspase-3. Therefore, MIPP may be a promising tumor-preventive agent, especially in human cervical cancer.

In vitro Anti-colorectal Cancer Potential of the Medicinal Mushroom Ganoderma neo-japonicum Imazeki in Hyperglycemic Condition: Impact on Oxidative Stress, Cell Cycle and Apoptosis

Clinical efficacy of chemotherapy is often compromised by diabetogenic glucose on colorectal cancer (CRC). High glucose has been shown to diminish the cytotoxicity of anticancer drugs. The issue can potentially be addressed with natural products. Recently, we revealed that Ganoderma neo-japonicum exhibits inhibitory activities against human colonic carcinoma cells. In this study, the impacts of hexane fraction (Hex, sterol-enriched) and chloroform fraction (Chl, terpenoid-enriched) were further elucidated. The cellular responses, including oxidative stress, cell cycle, and apoptosis were compared between the presence of normal glucose (NG, 5.5 mM) and high glucose (HG, 25 mM). HG promoted cell viability with concomitant elevation of GSH level. Both Hex and Chl fractions stimulated NO production, in addition, induced cell cycle arrest. The apoptotic effect of Hex fraction was glucose-dependent, but Chl fraction triggered apoptosis with an equivalent extent in NG and HG conditions. Overall, the active fractions from G. neo-japonicum show therapeutic potential in managing hyperglycemia-associated CRC.

Antioxidant Versus Pro-Apoptotic Effects of Mushroom-Enriched Diets on Mitochondria in Liver Disease

Mitochondria play a central role in non-alcoholic fatty liver disease (NAFLD) progression and in the control of cell death signalling during the progression to hepatocellular carcinoma (HCC). Associated with the metabolic syndrome, NAFLD is mostly driven by insulin-resistant white adipose tissue lipolysis that results in an increased hepatic fatty acid influx and the ectopic accumulation of fat in the liver. Upregulation of beta-oxidation as one compensatory mechanism leads to an increase in mitochondrial tricarboxylic acid cycle flux and ATP generation. The progression of NAFLD is associated with alterations in the mitochondrial molecular composition and respiratory capacity, which increases their vulnerability to different stressors, including calcium and pro-inflammatory molecules, which result in an increased generation of reactive oxygen species (ROS) that, altogether, may ultimately lead to mitochondrial dysfunction. This may activate further pro-inflammatory pathways involved in the progression from steatosis to steatohepatitis (NASH). Mushroom-enriched diets, or the administration of their isolated bioactive compounds, have been shown to display beneficial effects on insulin resistance, hepatic steatosis, oxidative stress, and inflammation by regulating nutrient uptake and lipid metabolism as well as modulating the antioxidant activity of the cell. In addition, the gut microbiota has also been described to be modulated by mushroom bioactive molecules, with implications in reducing liver inflammation during NAFLD progression. Dietary mushroom extracts have been reported to have anti-tumorigenic properties and to induce cell-death via the mitochondrial apoptosis pathway. This calls for particular attention to the potential therapeutic properties of these natural compounds which may push the development of novel pharmacological options to treat NASH and HCC. We here review the diverse effects of mushroom-enriched diets in liver disease, emphasizing those effects that are dependent on mitochondria.

Positive Selection of Squalene Synthase in Cucurbitaceae Plants

Triterpenoid saponins are secondary metabolites synthesized through isoprenoid pathways in plants. Cucurbitaceae represent an important plant family in which many species contain cucurbitacins as secondary metabolites synthesized through isoprenoid and triterpenoid pathways. Squalene synthase (SQS) is required for the biosynthesis of isoprenoids, but the forces driving the evolution of SQS remain undetermined. In this study, 10 SQS cDNA sequences cloned from 10 species of Cucurbitaceae and 49 sequences of SQS downloaded from GenBank and UniProt databases were analyzed in a phylogenetic framework to identify the evolutionary forces for functional divergence. Through phylogenetic construction and positive selection analysis, we found that SQS sequences are under positive selection. The sites of positive selection map to functional and transmembrane domains. 180L, 189S, 194S, 196S, 265I, 289P, 389P, 390T, 407S, 408A, 410R, and 414N were identified as sites of positive selection that are important during terpenoid synthesis and map to transmembrane domains. 196S and 407S are phosphorylated and influence SQS catalysis and triterpenoid accumulation. These results reveal that positive selection is an important evolutionary force for SQS in plants. This provides new information into the molecular evolution of SQS within the Cucurbitaceae family.

Comparative transcriptome analysis reveals relationship of three major domesticated varieties of Auricularia auricula-judae

Auricularia auricula-judae is an edible mushroom and a traditional medicine in China as well as the fourth largest cultivated mushroom species in the world. Here for the first time, we present comparative transcriptome analyses of the fruiting bodies of three morphologically distinguishable A. auricula-judae cultivated varieties (Wujin, smooth; Banjin, partially wrinkled; and Quanjin, fully wrinkled) collected from Jilin Province, China. Biological triplicates were performed to determine the expression levels of 13,937 unigenes. Among them, only 13 unigenes were annotated to A. auricula-judae, highlighting the lack of publicly available reference sequences for this economically important species. Principal component analysis (PCA) determined that the gene expression profile of Quanjin was unique when compared to those of Banjin and Wujin. Such relationships were further supported by analyses of annotated and unannotated unigenes, differentially expressed unigenes, gene ontology functions, and the family of peroxidase genes. Using the KEGG database, significant alternations in biological pathways were detected among the three cultivars. This work contributes a large set of A. auricula-judae sequences to public database, establishes the relationships among major cultivars, and provides molecular guidance for breeding and cultivation.

Antioxidant Activity and Neuroprotective Activity of Stilbenoids in Rat Primary Cortex Neurons via the PI3K/Akt Signalling Pathway

Antioxidant activity and neuroprotective activity of three stilbenoids, namely, trans-4-hydroxystilbene (THS), trans-3,5,4′-trihydroxy-stilbene (resveratrol, RES), and trans-3′,4′,3,5-tetrahydroxy-stilbene (piceatannol, PIC), against β-amyloid (Aβ)-induced neurotoxicity in rat primary cortex neurons were evaluated. THS, RES, and PIC significantly scavenged DPPH• and •OH radicals. All three stilbenoids were able to inhibit Aβ neurotoxicity by decreasing intracellular reactive oxygen species (ROS) via the PI3K/Akt signalling pathway. Specifically, stilbenoids significantly promoted Akt phosphorylation; suppressed Bcl-2/Bax expression; and inhibited caspase-9, caspase-3, and PARP cleavage. Molecular docking between stilbenoids with Akt indicated that stilbenoids could form hydrogen bond interactions with the COOH-terminal region of Akt. Additionally, the neuroprotective activity of stilbenoids correlated with the number and position of hydroxyl groups. The lack of meta-dihydroxyl groups on THS did not affect its neuroprotective activity in comparison with RES, whereas the ortho-dihydroxyl moiety on PIC significantly enhanced neuroprotective activity. These results provide new insights into the correlation between the biological activity and chemical structure of stilbenoids.

Anticancer effect of SZC015 on pancreatic cancer via mitochondria-dependent apoptosis and the constitutive suppression of activated nuclear factor κB and STAT3 in vitro and in vivo

Pancreatic cancer is the fourth leading cause of cancer-related death worldwide. Advances in therapeutic strategies such as chemotherapy have improved the clinical outcomes for pancreatic cancer patients. However, developing new therapeutic compounds against pancreatic cancer is still urgent due to the poor prognosis. Here, we show that SZC015, an oleanolic acid derivative, exhibits potent inhibitory effect on both pancreatic cancer cells in vitro and the corresponding xenograft tumors in vivo. Mechanistically, the activation of intrinsic apoptosis and G₁ phase arrest resulting from mitochondria damage caused by SZC015 contribute significantly to the anticancer effects of SZC015. SZC015 also has remarkably inhibitory effects on the transcription factors that are extensively activated in pancreatic cancer tissues. As a constitutively activated transcription factor in pancreatic cancer, the nuclear factor κB is highly suppressed after SZC015 treatment in vitro or administration in vivo. Based on the bioinformatics analysis of microarray data, we validate that JAK2/STAT3 signaling is indeed activated in the human pancreatic cancer tissues and SZC015 also shows inhibitory effect on this signaling both in vitro and in vivo. These data suggest the potent effects of SZC015 on pancreatic cancer and also provided novel insights into the mechanisms of SZC015 as a new potent candidate for treating pancreatic cancer.

Dose matters: Direct killing or immunoregulatory effects of natural polysaccharides in cancer treatment

Polysaccharides from natural resources possess anti-tumor activities for decades, but the efficacy of polysaccharides as the adjuvant drugs for cancer treatment at prescribed doses remains open for debate. In this review, molecular mechanisms involved in direct killing effects of polysaccharides, including apoptosis, cell cycle arrest and mitochondria/DNA damage were described. However, the concentrations/doses used to reach the direct killing effects are too high to be applicable. Polysaccharides can also exert anti-tumor effects through immunoregulation at lower doses, and the effects of polysaccharides on natural killer cells, dendritic cells and other lymphocytes for tumor destruction, along with the receptor recognition and downstream signaling pathways, were delineated. Unfortunately, the prescribed doses of polysaccharides are too low to stimulate immunoresponse, resulting in the failure of some clinical trials. Therefore, understanding the sophisticated mechanisms of the immunoregulatory function of natural polysaccharides with refined doses for clinical use will help the standardization of traditional medicine.

A Preclinical Evaluation of the Antitumor Activities of Edible and Medicinal Mushrooms: A Molecular Insight

Cancer is the leading cause of morbidity and mortality around the globe. For certain types of cancer, chemotherapy drugs have been extensively used for treatment. However, severe side effects and the development of resistance are the drawbacks of these agents. Therefore, development of new agents with no or minimal side effects is of utmost importance. In this regard, natural compounds are well recognized as drugs in several human ailments, including cancer. One class of fungi, “mushrooms,” contains numerous compounds that exhibit interesting biological activities, including antitumor activity. Many researchers, including our own group, are focusing on the anticancer potential of different mushrooms and the underlying molecular mechanism behind their action. The aim of this review is to discuss PI3K/AKT, Wnt-CTNNB1, and NF-κB signaling pathways, the occurrence of genetic alterations in them, the association of these aberrations with different human cancers and how different nodes of these pathways are targeted by various substances of mushroom origin. We have given evidence to propose the therapeutic attributes and possible mode of molecular actions of various mushroom-originated compounds. However, anticancer effects were typically demonstrated in in vitro and in vivo models and very limited number of studies have been conducted in the human population. It is our belief that this review will help the research community in designing concrete preclinical and clinical studies to test the anticancer potential of mushroom-originated compounds on different cancers harboring particular genetic alteration(s).

Effects of Saikosaponin D on apoptosis in human U87 glioblastoma cells

Saikosaponin D (SSd) is a type of Saponin derivative, which is a component extracted from Bupleurum falactum. SSd has been reported to exert anticancer activities. However, the effects of SSd on gliomas have not been elucidated. The aim of the present study was to investigate the pharmacological functions and potential molecular mechanisms of SSd in human U87 glioblastoma cells. The cells were treated with SSd at various concentrations for 48 h, the cell viability was assessed with 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium assay, and the activation of Akt, extracellular signal‑regulated kinases (ERK), c‑Jun N‑terminal kinases (JNK) and caspase‑3 was assessed by western blotting. In addition, apoptosis levels were analyzed with Hoechst 33258 and Annexin V staining. The results demonstrated that treatment of the U87 glioma cells with SSd markedly suppressed cell proliferation in a dose‑dependent manner. Meanwhile, SSd treatment enhanced apoptosis in the U87 cells. Furthermore, SSd significantly inhibited the phosphorylation of Akt and ERK, and promoted phosphorylated‑JNK and cleaved caspase‑3 expression. The present study revealed the potential therapeutic effects of SSd in the treatment of gliomas, and the cytotoxic effects of SSd in U87 cells were at least partly attributed to the depression of phosphatidylinositol 3‑kinase/Akt and ERK protein expression levels, and activation of JNK and caspase-3 expression.

Advances in antitumor polysaccharides from phellinus sensu lato: Production, isolation, structure, antitumor activity, and mechanisms

Edible and medicinal fungi (mushrooms) are widely applied to functional foods and nutraceutical products because of their proven nutritive and medicinal properties. Phellinus sensu lato is a well-known medicinal mushroom that has long been used in preventing ailments, including gastroenteric dysfunction, diarrhea, hemorrhage, and cancers, in oriental countries, particularly in China, Japan, and Korea. Polysaccharides represent a major class of bioactive molecules in Phellinus s. l., which have notable antitumor, immunomodulatory, and medicinal properties. Polysaccharides that were isolated from fruiting bodies, cultured mycelia, and filtrates of Phellinus s. l. have not only activated different immune responses of the host organism but have also directly suppressed tumor growth and metastasis. Studies suggest that polysaccharides from Phellinus s. l. are promising alternative anticancer agents or synergizers for existing antitumor drugs. This review summarizes the recent development of polysaccharides from Phellinus s. l., including polysaccharide production, extraction and isolation methods, chemical structure, antitumor activities, and mechanisms of action.

Crude extract of Rheum palmatum L. Induces cell cycle arrest S phase and apoptosis through mitochondrial-dependent pathways in U-2 OS human osteosarcoma cells

Cancer is the second cause of death in children. Osteosarcoma is the most common primary malignancy of solid bone cancer primarily affecting adolescents and young adults. In the Chinese population, the crude extract of Rheum palmatum L. (CERP) has been used for treating different diseases, including SARS, rheumatoid arthritis, coxsackievirus B3, and human colon cancer cell, pancreatic cancer. There are no reports on CERP and human osteosarcoma cells. The present study examined effects of CERP on cytotoxicity including cell cycle distribution and cell death (apoptosis) in U-2 OS human osteosarcoma cells. CERP significantly induced S phase arrest in U-2 OS cells in a dose-dependent. CERP produced DNA damage and DNA condensation. Other effects of CERP were stimulation of ROS and Ca(2+) , mitochondria impairment, and activation of caspase-3, -8, and -9. CERP increased the levels of Bax, Bak, Bad, cyclin B, Fas, PARP, GRP78, GADD153, AIF, Endo G, Calpain-2, p21, and p27, but decreased the levels of Bcl-2, BCL-X, XIAP, Akt, CDC25A, CDK2, Cyclin A, and Cyclin E of U-2 OS cells. It was also observed that CERP promoted the expression of AIF, Endo G, GADD153, and cytochrome c. These results indicate that CERP has anticancer effects in vitro and provide the foundation for in vivo studies of animal models of osteosarcoma. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 957-969, 2016.

Protocatechualdehyde Induces S-Phase Arrest and Apoptosis by Stimulating the p27(KIP1)-Cyclin A/D1-CDK2 and Mitochondrial Apoptotic Pathways in HT-29 Cells

Protocatechualdehyde (PCA) extracted from Phellinus gilvus exhibits anti-cancer activity in human colorectal carcinoma cells (HT-29). However, the underlying mechanisms remain poorly understood. We performed an in vitro study involving MTT, flow cytometry, RT-PCR, and western blot analyses to investigate the effects of PCA treatment on cell proliferation, cell cycle distribution, apoptosis, and expression of several cell cycle-related genes in HT-29 cells. The treatment enhanced S-phase cell cycle and apoptosis in HT-29 cells in a dose-dependent manner. Western blot results showed that PCA treatment decreased the expression levels of cyclin A, cyclin D1, and p27^KIP1 but increased those of cyclin-dependent kinase 2 (CDK2) in HT-29 cells. Furthermore, the expression levels of B-cell lymphoma/leukemia-2 (Bcl-2) and B-cell lymphoma/leukemia-xL (Bcl-xL) were down-regulated, whereas the levels of BH3-interacting domain death agonist (Bid), Bcl-2 homologous antagonist/killer (Bak), and cytosolic cytochrome c were significantly upregulated. Thus, the enzymes caspases-9, -3, -8, and -6 were found to be activated in HT-29 cells with PCA treatment. These results indicate that PCA-induced S-phase cell cycle arrest and apoptosis involve p27^KIP1-mediated activation of the cyclin-A/D1-Cdk2 signaling pathway and the mitochondrial apoptotic pathway.

A proteomic analysis of mushroom polysaccharide-treated HepG2 cells

The anti-tumor properties of fungal polysaccharides have gained significant recognition in Asia and tropical America. In this study, the differential expression of proteins in normal HepG2 cells and those treated with polysaccharides that had been isolated from Phellinus linteus (PL), Ganoderma lucidum (GL) and Auricularia auricula (AA) was investigated. Using two-dimensional electrophoresis (2DE), a total of 104 protein spots were determined to be overexpressed in these cells compared with noncancerous regions. A total of 59 differentially expressed proteins were identified through MALDI-TOF-MS. In addition, 400 biological processes (BP), 133 cell components (CC) and 146 molecular functions (MF) were enriched by Gene Ontology (GO) analysis, and 78 KEGG pathways were enriched by pathway enrichment. Protein-Protein Interaction (PPI) analysis demonstrated the interaction networks affected by polysaccharides in HepG2 cells. Then, DJ-1 and 14-3-3 were identified as the key proteins in the networks, and the expression of the mRNA and proteins were evaluated using Real-time quantitative PCR (qRT-PCR) and Western blotting (WB), respectively. The results were in agreement with the 2DE. These results provided information on significant proteins of hepatocellular carcinoma (HCC) and form an important basis for the future development of valuable medicinal mushroom resources.

Polysaccharide from Phellinus linteus induces S-phase arrest in HepG2 cells by decreasing calreticulin expression and activating the P27kip1-cyclin A/D1/E-CDK2 pathway

ETHNOPHARMACOLOGY RELEVANCE

Our previous study showed that the proteoglycan P1 from Phellinus linteus (Mesima) exhibits significant anti-tumor activity against human hepatocellular carcinoma cells (HepG2); however, its molecular mechanism remains unknown. This study aims to provide insights into the mechanism of the anti-tumor activity of P1 against HepG2 cells.

METHODS

We examined the effects of P1 on HepG2 cell proliferation in vitro and in vivo. Flow cytometry was used to analyze the cell cycle distribution and apoptosis. Proteomic analysis, real-time (RT)-PCR, and Western blot were carried out to observe the expression of several cell cycle control proteins in HepG2 cells.

RESULTS

Both the volume and the weight of solid tumors were significantly decreased in P1-treated mice (200mg/kg) compared with the control. The HepG2 cells in the P1-treated tumors were significantly decreased, irregularly shaped, and smaller. P1 slightly increased the body weight of the tumor-bearing mice, which indicates that P1 is nontoxic to mammals at 200mg/kg. P1 also caused a significant dose-dependent increase in S phase arrest, but no apoptosis was observed in HepG2 cells. The results of the proteomic analysis, RT-PCR, and Western blot analysis showed that significantly downregulated expression of calreticulin, cyclin D1, cyclin E, and CDK2 and upregulated expression of P27 kip1 and cyclin A in the P1-treated HepG2 cells (200 μg/ml).

CONCLUSION

These results suggest that calreticulin expression and the P27 kip1-cyclin A/D1/E-CDK2 pathway were involved in P1-induced S-phase cell cycle arrest in HepG2 cells.

Activation of P27kip1-cyclin D1/E-CDK2 pathway by polysaccharide from Phellinus linteus leads to S-phase arrest in HT-29 cells

Our previous study showed that polysaccharide (P1) from Phellinus linteus exhibits a significant inhibitive activity on human colorectal carcinoma cells (HT-29). However its novel molecular mechanism remains unknown. To obtain insights into P1's mechanism of action, we examined its effects on cell proliferation in vitro and in vivo, cell cycle distribution, apoptosis, autophagy, and expression of several cell cycle interrelated proteins in HT-29 cells. Interestingly, we found that volume and weight of the solid tumor significantly decreased in P1 (200mg/kg)-treated mice compared with the control. However, slightly increased the body weight of the P1 treated tumor-bearing mice, with no significant increased ALT, AST levels in serum and LPO concentration in liver and kidney indicated that P1 has no toxicity to mammals at a dose of 200mg/kg. Furthermore, P1 caused a significantly dose-dependent increase in the S-phase cell cycle, but no apoptosis and autophagy in HT-29 cells. RT-PCR and Western blot results showed significantly down-regulated expressions of cyclin D1, cyclin E, and CDK2, as well as increased expressions of P27kip1 in P1 (100 μg/mL)-treated HT-29 cells. These results suggested that the activation of P27kip1-cyclin D1/E-CDK2 pathway is involved in P1-induced S-phase cell cycle arrest in HT-29 cells.

Optimization for production of exopolysaccharides with antitumor activity in vitro from Paecilomyces hepiali

In the present study, optimal medium for the growth of mycelia and the production of exopolysaccharides from Paecilomyces hepiali HN1 (PHEPS) in submerged culture was investigated. As a result, the maximum production of mycelia (12.98 ± 0.14 g/L) and PHEPS (5.33 ± 0.11 g/L) were achieved under the optimal medium of sucrose 46.08 g/L, yeast extract 4.71 g/L, (NH₄)₂SO₄ 5.72 g/L, KH₂PO₄ 1.70 g/L, CaCl₂ 0.50 g/L, MgSO₄ 0.50 g/L, potato extract 1% and malt extract 1%. Furthermore, the antitumor activity of PHEPS in vitro was evaluated by using three cell lines of human liver tumor HepG2 cells, breast cancer MCF-7 cells and cervical cancer Hela cells. It was found that PHEPS exhibited relative higher anti-proliferative activity against HepG2 cells than MCF-7 cells and Hela cells. At a concentration of 500 μg/mL and 72 h treatment, the inhibition rate of PHEPS on HepG2 cells reached to 62.58%. All these results suggested that PHEPS could be explored as novel natural antitumor agent with great potential application.