Blockade of the Ras/Raf/ERK and Ras/PI3K/Akt Pathways by Monacolin K Reduces the Expression of GLO1 and Induces Apoptosis in U937 Cells

Identification of the high-yield monacolin K strain from Monascus spp. and its submerged fermentation using different medicinal plants

BACKGROUND

Medical plants confer various benefits to human health and their bioconversion through microbial fermentation can increase efficacy, reduce toxicity, conserve resources and produce new chemical components. In this study, the cholesterol-lowering monacolin K genes and content produced by Monascus species were identified. The high-yield monacolin K strain further fermented with various medicinal plants. The antioxidant and anti-inflammatory activities, red pigment and monacolin K content, total phenolic content, and metabolites in the fermented products were analyzed.

RESULTS

Monacolin K was detected in Monascus pilosus (BCRC 38072), and Monascus ruber (BCRC 31533, 31523, 31534, 31535, and 33323). It responded to the highly homologous mokA and mokE genes encoding polyketide synthase and dehydrogenase. The high-yield monacolin K strain, M. ruber BCRC 31535, was used for fermentation with various medicinal plants. A positive relationship between the antioxidant capacity and total phenol content of the fermented products was observed after 60 days of fermentation, and both declined after 120 days of fermentation. By contrast, red pigment and monacolin K accumulated over time during fermentation, and the highest monacolin K content was observed in the fermentation of Glycyrrhiza uralensis, as confirmed by RT-qPCR. Moreover, Monascus-fermented medicinal plants including Paeonia lactiflora, Alpinia oxyphylla, G. uralensis, and rice were not cytotoxic. Only the product of Monascus-fermented G. uralensis significantly exhibited the anti-inflammatory capacity in a dose-dependent manner in lipopolysaccharide-induced Raw264.7 cells. The metabolites of G. uralensis with and without fermentation (60 days) were compared by LC/MS. 2,3-Dihydroxybenzoic acid, 3,4-dihydroxyphenylglycol, and 3-amino-4-hydroxybenzoate were considered to enhance the antioxidant and anti-inflammatory ability.

CONCLUSIONS

Given that highly homologous monacolin K and citrinin genes can be observed in Monascus spp., monacolin K produced by Monascus species without citrinin genes can be detected through the complementary methods of PCR and HPLC. In addition, the optimal fermentation time was important to the acquisition of antioxidants, red pigment and monacolin K. These bioactive substances were significantly affected by medicinal plants over fermentation time. Consequently, Monascus-fermented G. uralensis had a broad spectrum of biological activities.

Improving Sperm Cryopreservation With Type III Antifreeze Protein: Proteomic Profiling of Cynomolgus Macaque (Macaca fascicularis) Sperm

Antifreeze protein III (AFP III) is used for the cryopreservation of germ cells in various animal species. However, the exact mechanism of its cryoprotection is largely unknown at the molecular level. In this study, we investigated the motility, acrosomal integrity, and mitochondrial membrane potential (MMP), as well as proteomic change, of cynomolgus macaque sperm after cryopreservation. Sperm motility, acrosomal integrity, and MMP were lower after cryopreservation (p < 0.001), but significant differences in sperm motility and MMP were observed between the AFP-treated sperm sample (Cryo+AFP) and the non-treated sample (Cryo–AFP) (p < 0.01). A total of 141 and 32 differentially expressed proteins were, respectively, identified in cynomolgus macaque sperm cryopreserved without and with 0.1 μg/ml AFP III compared with fresh sperm. These proteins were mainly involved in the mitochondrial production of reactive oxygen species (ROS), glutathione (GSH) synthesis, and cell apoptosis. The addition of AFP III in the sperm freezing medium resulted in significant stabilization of cellular molecular functions and/or biological processes in sperm, as illustrated by the extent of proteomic changes after freezing and thawing. According to the proteomic change of differentially expressed proteins, we hypothesized a novel molecular mechanism for cryoprotection that AFP III may reduce the release of cytochrome c and thereby reduce sperm apoptosis by modulating the production of ROS in mitochondria. The molecular mechanism that AFP III acts with sperm proteins for cellular protection against cryoinjuries needs further study.

An overview on the biological activity and anti-cancer mechanism of lovastatin

Lovastatin, a secondary metabolite isolated from fungi, is often used as a representative drug to reduce blood lipid concentration and treat hypercholesterolemia. Its structure is similar to that of HMG-CoA. Lovastatin inhibits the binding of the substrate to HMG-CoA reductase, and strongly competes with HMG-CoA reductase (HMGR), thereby exerting a hypolipidemic effect. Further, its safety has been confirmed in vivo and in vitro. Lovastatin also has anti-inflammatory, anti-cancer, and neuroprotective effects. Therefore, the biological activity of lovastatin, especially its anti-cancer effect, has garnered research attention. Several in vitro studies have confirmed that lovastatin has a significant inhibitory effect on cancer cell viability in a variety of cancers (such as breast, liver, cervical, lung, and colon cancer). At the same time, lovastatin can also increase the sensitivity of some types of cancer cells to chemotherapeutic drugs and strengthen their therapeutic effect. Lovastatin inhibits cell proliferation and regulates cancer cell signaling pathways, thereby inducing apoptosis and cell cycle arrest. This article reviews the structure, biosynthetic pathways, and applications of lovastatin, focusing on the anti-cancer effects and mechanisms of action.

An overview on the biosynthesis and metabolic regulation of monacolin K/lovastatin

Lovastatin/monacolin K (MK) is used as a lipid lowering drug, due to its effective hypercholesterolemic properties, comparable to synthetic statins. Lovastatin's biosynthetic pathway and gene cluster composition have been studied in depth in Aspergillus terreus. Evidence shows that the MK biosynthetic pathway and gene cluster in Monascus sp. are similar to those of lovastatin in A. terreus. Currently, research efforts have been focusing on the metabolic regulation of MK/lovastatin synthesis, and the evidence shows that a combination of extracellular and intracellular factors is essential for proper MK/lovastatin metabolism. Here, we comprehensively review the research progress on MK/lovastatin biosynthetic pathways, its synthetic precursors and inducing substances and metabolic regulation, with a view to providing reference for future research on fungal metabolism regulation and metabolic engineering for MK/lovastatin production.

High expression of GLO1 indicates unfavorable clinical outcomes in glioma patients

BACKGROUNDS

Glyoxalase I (GLO1), a ubiquitous enzyme involved in the process of detoxification of methylglyoxal in the cellular glycolysis pathway, was reported to be highly expressed in human tumor. It has also been found that GLO1 is associated with tumor cell survival and proliferation in some types of cancer, such as pancreatic cancer, hepatocellular carcinoma and gastric cancer. However, the role of GLO1 in glioma has not been clarified. The purpose of present study is to explore the expression pattern of GLO1 and whether the expression level of GLO1 is associated with the unfavorable clinical outcomes of patients with glioma.

METHODS

Quantitative RT-PCR and immunohistochemistry staining were used to investigate the mRNA and protein level of GLO1 in glioma tissues together with normal brain tissues. The prognostic role of GLO1 in glioma patients was assessed using univariate and multivariate analyses. Clinical outcomes were estimated by using the Kaplan-Meier analysis and the log-rank test. The function of GLO1 in glioma cell lines were investigated by in vitro experiments.

RESULTS

Expression level of GLO1 was higher in glioma tissues than that in normal brain tissues. High GLO1 expression was significantly correlated with WHO grade and the poor overall survival time in glioma patients. Moreover, GLO1 was also defined as an unfavorable prognosis factor. Overexpression of GLO1 in the glioma cell line U87 can enhance the tumor cell proliferation, migration and invasion. Whereas, knockdown of GLO1 can suppress those abilities.

CONCLUSIONS

Our studies demonstrated that GLO1 was highly expressed in glioma tissues and significantly correlated with the poor prognosis of glioma patients. It indicated that GLO1 might serve as a new prognostic predictor and therapeutic target for glioma treatment.

Distinct Responses of Cytotoxic Ganoderma lucidum Triterpenoids in Human Carcinoma Cells

The medicinal mushroom Ganoderma lucidum is well recognized for its effective cancer-preventative and therapeutic properties, while specific components responsible for these anticancer effects are not well studied. Six triterpenoids that are ganolucidic acid E, lucidumol A, ganodermanontriol, 7-oxo-ganoderic acid Z, 15-hydroxy-ganoderic acid S, and ganoderic acid DM were isolated and identified from an extract of the mushroom. All compounds reduced cell growth in three human carcinoma cells (Caco-2, HepG2, and HeLa cells) dose dependently with LC50s from 20.87 to 84.36 μM. Moreover, the six compounds induced apoptosis in HeLa cells with a maximum increase (22%) of sub-G1 accumulations and 43.03% apoptotic cells in terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay (15-hydroxy-ganoderic acid S treatment). Apoptosis was further confirmed by annexin-V staining. Four of the compounds also caused apoptosis in Caco-2 cells with maximum 9.5% increase of sub-G1 accumulations (7-oxo-ganoderic acid Z treatment) and maximum 29.84% apoptotic cells in TUNEL assay (ganoderic acid DM treatment). Contrarily, none of the compounds induced apoptosis in HepG2 cells. The different responses of the three cell lines following these treatments indicated that the bioactive properties of these compounds may vary from cells of different sites of origin and are likely acting under diverse regulatory mechanisms.