Dihydromyricetin induces apoptosis and cytoprotective autophagy through ROS-NF-κB signalling in human melanoma cells

Multiple molecular and cellular mechanisms of the antitumour effect of dihydromyricetin (Review)

Dihydromyricetin (DHM) is a natural flavonoid compound with multiple antitumour effects, including inhibition of proliferation, promotion of apoptosis, inhibition of invasion and migration, clearance of reactive oxygen species (ROS) and induction of autophagy. For example, DHM can effectively block the progression of the tumour cell cycle and inhibit cell proliferation. In different types of cancer cells, DHM can regulate the PI3K/Akt pathway, mTOR, and NF-κB pathway components, such as p53, and endoplasmic reticulum stress can alter the accumulation of ROS or induce autophagy to promote the apoptosis of tumour cells. In addition, when DHM is used in combination with various known chemotherapy drugs, such as paclitaxel, nedaplatin, doxorubicin, oxaliplatin and vinblastine, it can increase the sensitivity of tumour cells to DHM and increase the therapeutic effect of chemotherapy drugs. In the present review, the multiple molecular and cellular mechanisms underlying the antitumour effect of DHM, as well as its ability to increase the effects of various traditional antitumour drugs were summarized. Through the present review, it is expected by the authors to draw attention to the potential of DHM as an antitumour drug and provide valuable references for the clinical translation of DHM research and the development of related treatment strategies.

A comprehensive review of vine tea: Origin, research on Materia Medica, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Vine tea is a popular folk tea that has been consumed in China for more than 1200 years. It is often used in ethnic medicine by ethnic groups in southwest China with at least 35 aliases in 10 provinces. In coastal areas, vine tea is mostly used to treat heatstroke, aphtha, aphonia, toothache, etc. In contrast, in the southwest inland regions, vine tea is mostly used to clear away heat and toxic materials, antiphlogosis and relieving sore-throat, lowering blood pressure and lipid levels, and alleviating fatigue. Three main species have been used as the source of vine tea, Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla. Among them, the leaves of Nekemias grossedentata were considered as new food resource in complicance with regulations, according to the Food Safety Standards published by the Monitoring and Evaluation Department of the National Health and Family Planning Commission in China.

AIM OF THE STUDY

At present, the comprehensively summary of Materia Medica on the history and source of vine tea is currently unavailable. The current article summed up the Materia Medica, species origin and pharmacological effects of all 3 major species used in vine tea to fill the knowledge gaps. We also aim to provide a reference for future research on historical textual, resource development and medicinal utilization of vine tea.

MATERIALS AND METHODS

Adhering to the literature screening methodology outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this review encompasses 148 scholarly research papers from three database, paper ancient books, local chronicles and folklore through field investigations. We then comprehensively summarized and discussed research progresses in scientific and application studies of vine tea.

RESULTS

The historical records indicated that vine tea could have been used as early as Southern and Northern Dynasties (AC 420-589). Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla, were used to considered as vine tea in the ethnic medicine. The main phytochemicals found in three plants are flavonoids, polyphenols and terpenoids, among which dihydromyricetin (DHM) is the most important and most studied active substance. The key words "Ampelopsis grossedentata" (Synonym of Nekemias grossedentata) and "dihydromyricetin/DHM" showed the highest frequency over the last 27 year based on the research trend analysis. And the ethnopharmacology studies drawn the main activities of vine tea are antioxidant, antibacterial, hepatoprotective, neuroprotective and anti-atherosclerosis activities.

CONCLUSIONS

This review systematically summarized and discussed vine tea from the following five aspects, history, genetic relationship, phytochemistry, research trend and ethnopharmacology. Vine tea has a long historical usage in Chinese ethnic medicine. Its outstanding therapeutic efficacies have attracted extensive attention in other places in the world at present. Nekemias cantonensis and Nekemias megalophylla are quite similar to Nekemias grossedentata in terms of many aspects. However, the current research has a narrow focus on mainly Nekemias grossedentata and DHM. We propose that future studies could be carried out to determine the synergistic effect of multi-components and multi-targets of vine tea including all 3 species to provide valuable knowledge.

Dihydromyricetin Inhibits Pseudorabies Virus Multiplication In Vitro by Regulating NF-κB Signaling Pathway and Apoptosis

Pseudorabies virus (PRV) infections have caused huge economic losses to the breeding industry worldwide, especially pig husbandry. PRV could threaten human health as an easily ignored zoonotic pathogen. The emergence of new mutants significantly reduced the protective effect of vaccination, indicating an urgent need to develop specific therapeutic drugs for PRV infection. In this study, we found that dihydromyricetin (DMY) could dose-dependently restrain PRV infection in vitro with an IC50 of 161.34 μM; the inhibition rate of DMY at a concentration of 500 μM was 92.16 %. Moreover, the mode of action showed that DMY directly inactivated PRV virion and inhibited viral adsorption and cellular replication. DMY treatment could improve PRV-induced abnormal changes of the NF-κB signaling pathway and excessive inflammatory response through regulation of the contents of IκBα and p-P65/P65 and the transcriptional levels of cytokines (TNF-α, IL-1β and IL-6). Furthermore, DMY promoted the apoptosis of PRV-infected cells through the regulation of the expressions of Bax and Bcl-xl and the transcriptional levels of Caspase-3, Bax, Bcl-2 and Bcl-xl, thereby limiting the production of progeny virus. These findings indicated that DMY could be a candidate drug for the treatment of PRV infection.

Strategic developments in the drug delivery of natural product dihydromyricetin: applications, prospects, and challenges

Dihydromyricetin (DHM) is an important natural flavonoid that has attracted much attention because of its various functions such as protecting the cardiovascular system and liver, treating cancer and neurodegenerative diseases, and anti-inflammation effect, etc. Despite its great development potential in pharmacy, DHM has some problems in pharmaceutical applications such as low solubility, permeability, and stability. To settle these issues, extensive research has been carried out on its physicochemical properties and dosage forms to produce all kinds of DHM preparations in the past ten years. In addition, the combined use of DHM with other drugs is a promising strategy to expand the application of DHM. However, although invention patents for DHM preparations have been issued in several countries, the current transformation of DHM research results into market products is insufficient. To date, there is still a lack of deep research into the pharmacokinetics, pharmacodynamics, toxicology, and action mechanism of DHM preparations. Besides, preparations for combined therapy of DHM with other drugs are scarcely reported, which necessitates the development of dosage forms for this application. Apart from medicine, the development of DHM in the food industry is also of great potential. Due to its multiple effects and excellent safety, DHM preparations can be developed for functional drinks and foods. Through this review, we hope to draw more attention to the development potential of DHM and the above challenges and provide valuable references for the research and development of other natural products with a similar structure-activity relationship to this drug.

Bullatine A exerts anti-inflammatory effects by inhibiting the ROS/JNK/NF-κB pathway and attenuating systemic inflammatory responses in mice

CONTEXT

Aconiti brachypodi Radix (Xue-shang-yi-zhi-hao) is a traditional Chinese herbal medicine that is capable of anti-analgesic and anti-inflammatory effects. Bullatine A (BA) is one of the major active ingredients of this plant, and most of the previous studies reported that it has anti-analgesic effects. However, the mechanism of BA anti-inflammatory remains unclear.

OBJECTIVE

This study investigates the anti-inflammatory activities of BA, both in vitro and in vivo, and elucidates its mechanism.

MATERIALS AND METHODS

In vitro, BA (10, 20, 40 and 80 μM) was added to 1 µg/mL of lipopolysaccharide (LPS)-activated microglia BV2 cells and immortalized murine bone marrow-derived macrophages, respectively. After 6 h, the mRNA and protein levels of inflammatory factors were determined by real-time quantitative PCR and western blotting. In vivo, C57BL/6 mice were randomly divided into control, model (5 mg/kg dose of LPS) and treated groups (LPS with 5, 10 or 20 mg/kg dose of BA) to evaluate the anti-inflammatory efficacy of BA.

RESULTS

BA significantly inhibited LPS-induced expression of inflammatory factors, such as IL-1β, IL-6, TNF-α, inducible nitric oxide synthase (iNOS) and COX-2. Further investigations showed that BA reduced the translocation of NF-κB p65 (38.5%, p < 0.01). BA also reduced the phosphorylation of c-Jun N-terminal kinase (JNK) (11.2%, p < 0.05) and reactive oxygen species (ROS) generation (24.2%, p < 0.01). Furthermore, BA treatment attenuated the LPS-primed inflammatory response and liver and lung damage in vivo.

CONCLUSIONS

BA can inhibit the inflammatory response in part through the ROS/JNK/NF-κB signalling pathway, providing a theoretical basis for the clinical application of BA in the treatment of periphery inflammatory diseases.

Role of ROS‑mediated autophagy in melanoma (Review)

Melanoma is the most aggressive form of skin cancer with the poorest prognosis and its pathogenesis has yet to be fully elucidated. As key factors that regulate cellular homeostasis, both reactive oxygen species (ROS) and autophagy are involved in the development of melanoma, from melanomagenesis to progression and drug resistance. However, the interaction between ROS and autophagy in the etiology and treatment of melanoma is not well characterized. The present review examined the production of ROS and the role of oxidative stress in melanoma, and summarized the role of ROS‑mediated autophagy in melanomagenesis and melanoma cell fate decision following treatment with various anticancer drugs. The present findings may lead to a better understanding of the pathogenesis and progression of melanoma, and suggest promising treatment options for this disease.

Comprehensive analysis of dihydromyricetin metabolites in rats using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry

As the most abundant and bioactive constituent in vine tea (Ampelopsis grossedentata), dihydromyricetin possesses numerous biological activities. A rapid profiling and identification method for dihydromyricetin metabolites in rats after the oral administration has been established using UHPLC-Q-Exactive Orbitrap MS coupled with multiple data-mining methods. Herein, an efficient analytical strategy characterized by parallel reaction monitoring mode combining diagnostic fragment ions filtering techniques was developed for the comprehensive identification of dihydromyricetin metabolites in rat plasma, urine and faeces. And then, the biotransformation pathways of dihydromyricetin were further revealed. As a result, a total of 49 metabolites were finally identified by comparing diagnostic fragment ions, chromatographic retention times, neutral loss fragment ions, and accurate mass measurement with those of dihydromyricetin reference standard. These metabolites were presumed to be dominantly generated through hydroxylation, dehydroxylation, methylation, reduction, sulfation, decarbonylation, glucuronidation, glucosylation, and their composite reactions. In a word, our present results not only supplied solid foundation to better understand the action mechanism of dihydromyricetin, but also provided some models for metabolism study of the other compounds in traditional Chinese medicines or other natural plants. This article is protected by copyright. All rights reserved.

Pro-Apoptotic Effect of Zeolitic Imidazolate Framework-8 (ZIF-8)-Loaded Dihydromyricetin on HepG2 Cells

Dihydromyricetin (DHM) has garnered attention due to its promising antitumor activity, but its low bioavailability restricts its clinical application. Thus, developing nano-drug delivery systems could enhance its antitumor activity. We prepared DHM@ZIF-8 nanoparticles using the zeolite imidazole framework-8 (ZIF-8) as a carrier loaded with dihydromyricetin. A series of characterizations were performed, including morphology, particle size, zeta potential, X-single crystal diffraction, ultraviolet spectroscopy, infrared spectroscopy, and Brunauer–Emmett–Teller (BET). The in vitro release characteristics of DHM@ZIF-8 under pH = 5.0 and pH = 7.4 were studied using membrane dialysis. The antitumor activity and pro-apoptotic mechanism of DHM@ZIF-8 were investigated through CCK-8 assay, reactive oxygen species (ROS), Annexin V/PI double-staining, transmission electron microscopy, and Western blot. The results depicted that DHM@ZIF-8 possessed a regular morphology with a particle size of 211.07 ± 9.65 nm (PDI: 0.19 ± 0.06) and a Zeta potential of −28.77 ± 0.67 mV. The 24 h drug releasing rate in PBS solution at pH = 7.4 was 32.08% and at pH = 5.0 was 85.52% in a simulated tumor micro acid environment. DHM@ZIF-8 could significantly enhance the killing effect on HepG2 cells compared to the prodrug. It can effectively remove ROS from the tumor cells, promote apoptosis, and significantly affect the expression of apoptosis-related proteins within tumor cells.

Present Status, Challenges, and Prospects of Dihydromyricetin in the Battle against Cancer

Dihydromyricetin (DHM) is a natural flavonoid compound extracted from Ampelopsis grossedentata that has been used for centuries in traditional Chinese medicine. DHM has attracted intensive attention due to its numerous beneficial activities, such as hepatoprotection, cardioprotection, antioxidant, and anti-inflammation. In addition, DHM inhibits the progression of cancers such as lung cancer, hepatocellular cancer, breast cancer, melanoma, and malignant reproductive systems through multiple mechanisms, including antiangiogenesis, antiproliferation, apoptosis, and inhibition of invasion and migration. Notably, DHM also activates autophagy at different levels, exerting a dual-regulatory effect on cancers. Mechanistically, DHM can effectively regulate mammalian target of rapamycin (mTOR), noncoding RNA-mediated signaling, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway, nuclear factor-κB (NF-κB), p53, and endoplasmic reticulum stress (ER stress)-driven signaling in different types of cancers. DHM has also been shown to have inhibitory effects on various regulators that trigger epithelial–mesenchymal transition (EMT). Furthermore, DHM exhibits a remarkable anticancer reversal ability when used in combination with drugs such as adriamycin, nedaplatin, and other drugs. However, the low bioavailability of DHM limits its potential applications, which are improved through structural modification and the exploration of novel dosage forms. Therefore, DHM may become a promising candidate for treating malignancies alone or combined with conventional anticancer strategies used in clinical practice.

A multifaceted review on dihydromyricetin resources, extraction, bioavailability, biotransformation, bioactivities, and food applications with future perspectives to maximize its value

Natural bioactive compounds present a better alternative to prevent and treat chronic diseases owing to their lower toxicity and abundant resources. (+)-Dihydromyricetin (DMY) is a flavanonol, possessing numerous interesting bioactivities with abundant resources. This review provides a comprehensive overview of the recent advances in DMY natural resources, stereoisomerism, physicochemical properties, extraction, biosynthesis, pharmacokinetics, and biotransformation. Stereoisomerism of DMY should be considered for better indication of its efficacy. Biotechnological approach presents a potential tool for the production of DMY using microbial cell factories. DMY high instability is related to its powerful antioxidant capacity due to pyrogallol moiety in ring B, and whether preparation of other analogues could demonstrate improved properties. DMY demonstrates poor bioavailability based on its low solubility and permeability with several attempts to improve its pharmacokinetics and efficacy. DMY possesses various pharmacological effects, which have been proven by many in vitro and in vivo experiments, while clinical trials are rather scarce, with underlying action mechanisms remaining unclear. Consequently, to maximize the usefulness of DMY in nutraceuticals, improvement in bioavailability, and better understanding of its actions mechanisms and drug interactions ought to be examined in the future along with more clinical evidence.

Oxidative Stress and Autophagy as Key Targets in Melanoma Cell Fate

Melanoma originates from the malignant transformation of melanocytes and is one of the most aggressive forms of cancer. The recent approval of several drugs has increased the chance of survival although a significant subset of patients with metastatic melanoma do not show a long-lasting response to these treatments. The complex cross-talk between oxidative stress and the catabolic process autophagy seems to play a central role in all aspects of melanoma pathophysiology, from initiation to progression and metastasis, including drug resistance. However, determining the fine role of autophagy in cancer death and in response to redox disruption is still a fundamental challenge in order to advance both basic and translational aspects of this field. In order to summarize the interactions among reactive oxygen and nitrogen species, autophagy machinery and proliferation/growth/death/apoptosis/survival, we provide here a narrative review of the preclinical evidence for drugs/treatments that modulate oxidative stress and autophagy in melanoma cells. The significance and the potential for pharmacological targeting (also through multiple and combination approaches) of these two different events, which can contribute independently or simultaneously to the fate of melanoma, may help to define new processes and their interconnections underlying skin cancer biology and unravel new reliable approaches.

3-methyadenine inhibits lipopolysaccharides-induced pulmonary inflammation at the early stage of silicosis via blocking NF-κB signaling pathway

Occupational exposure to silica dust is related to pulmonary inflammation and silicosis. Lipopolysaccharides (LPSs) could aggravate apoptosis in alveolar macrophages (AMs) of human silicosis through autophagy, yet how the reduction of autophagy attenuated LPS-induced lung injury and the related mechanisms need to be investigated. In the study, we aim to understand the role of 3-methyladenine (3-MA), an inhibitor of autophagy, in LPS-mediated inflammatory responses and fibrosis. We collected AMs from observers/silicosis patients. The results showed that LPS induced NF-κB-related pulmonary inflammation in observers and silicosis patients, as confirmed by an increase in the expression of IL-1β, IL-6, TNF-α, and p65, which could be inhibited by 3-MA treatment. In mice models, at the early stage (7d) of silicosis, but not the late (28d) stage, blocking autophagy reversed the increased levels of IL-1β, IL-6, TNF-α, and p65 caused by LPS. Mechanism study revealed that LPS triggered the expression of LC3 II, p62, and cleaved caspase-3 at the early stage exposed to silica, which could be restored by 3-MA, while there was no difference in the expression of LAMP1 either at the early or late stage of silicosis in different groups. Similarly, 3-MA treatment did not prevent fibrosis characterized by destroyed alveoli, collagen deposition, and increased expression of α-SMA and Col-1 induced by LPS at the late stage of silicosis. The results suggested that 3-MA has a role in the protection of lung injury at the early stage of silicosis and provided an experimental basis for preventive strategies of pulmonary inflammation and silicosis.

Molecular mechanisms and therapeutic implications of dihydromyricetin in liver disease

Recent studies demonstrated that dihydromyricetin (DHM) has prominent therapeutic effects on liver injury and liver cancer. By summarizing the current preclinical in vitro and in vivo studies, the present review examines the preventive and therapeutic effects of DHM on liver disorders as well as its potential mechanisms. Briefly, in both chemical- and alcohol-induced liver injury models, DHM ameliorates hepatocyte necrosis and steatosis while promoting liver regeneration. In addition, DHM can alleviate nonalcoholic fatty liver disease (NAFLD) via regulating lipid/glucose metabolism, probably due to its anti-inflammatory or sirtuins-dependent mechanisms. Furthermore, DHM treatment inhibits cell proliferation, induces apoptosis and autophagy and regulates redox balance in liver cancer cells, thus exhibiting remarkable anti-cancer effects. The pharmacological mechanisms of DHM may be associated with its anti-inflammatory, anti-oxidative and apoptosis-regulatory benefits. With the accumulating interests in utilizing natural products to target common diseases, our work aims to improve the understanding of DHM acting as a novel drug candidate for liver diseases and to accelerate its translation from bench to bedside.

Anticancer effects of dihydromyricetin on the proliferation, migration, apoptosis and in vivo tumorigenicity of human hepatocellular carcinoma Hep3B cells

Background

Hepatocellular carcinoma (HCC) represents a serious public health problem worldwide and has high morbidity and mortality. Dihydromyricetin (DHM) exhibits anticancer effect on a variety of malignancies, but its anticancer function of DHM in HCC has been unclear. The aim of this study was designed to investigate the anticancer effect of DHM on cell apoptosis, proliferation, migration and invasion of hepatoma carcinoma cells.

Methods

Cultured Hep3B cells were treated with different DHM concentrations, followed by cell apoptosis, proliferation, migration and invasion were examined by CCK-8, colony formation assay, wound healing, Transwell and flow cytometry, respectively. The mRNA and protein expression of BCL-2, Cleaved-caspase 3, Cleaved-caspase 9, BAK, BAX and BAD were validated by western blot.

Results

DHM markedly suppressed proliferation, migration, invasion and facilitated apoptosis in Hep3B cells. Mechanistically, DHM significantly downregulated the Bcl-2 expression, and upregulated the mRNA and protein levels of Cleaved-Caspase 3, Cleaved- Caspase 9, Bak, Bax and Bad. Furthermore, in the nude mice tumorigenic model, DHM treatment greatly decreased the weight of the HCC cancers compared to the weights in control and NDP group.

Conclusions

DHM could suppress cell proliferation, migration, invasion, and facilitated apoptosis in Hep3B cells. These findings could provide novel insights to develop potential therapeutic strategy for the clinical treatment of HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03356-5.

Ampelopsin Inhibits Cell Proliferation and Induces Apoptosis in HL60 and K562 Leukemia Cells by Downregulating AKT and NF-κB Signaling Pathways

Leukemia is a type of blood cancer caused by the rapid proliferation of abnormal white blood cells. Currently, several treatment options, including chemotherapy, radiation therapy, and bone marrow transplantation, are used to treat leukemia, but the morbidity and mortality rates of patients with leukemia are still high. Therefore, there is still a need to develop more selective and less toxic drugs for the effective treatment of leukemia. Ampelopsin, also known as dihydromyricetin, is a plant-derived flavonoid that possesses multiple pharmacological functions, including antibacterial, anti-inflammatory, antioxidative, antiangiogenic, and anticancer activities. However, the anticancer effect and mechanism of action of ampelopsin in leukemia remain unclear. In this study, we evaluated the antileukemic effect of ampelopsin against acute promyelocytic HL60 and chronic myelogenous K562 leukemia cells. Ampelopsin significantly inhibited the proliferation of both leukemia cell lines at concentrations that did not affect normal cell viability. Ampelopsin induced cell cycle arrest at the sub-G1 phase in HL60 cells but the S phase in K562 cells. In addition, ampelopsin regulated the expression of cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors differently in each leukemia cell. Ampelopsin also induced apoptosis in both leukemia cell lines through nuclear condensation, loss of mitochondrial membrane potential, increase in reactive oxygen species (ROS) generation, activation of caspase-9, caspase-3, and poly ADP-ribose polymerase (PARP), and regulation of Bcl-2 family members. Furthermore, the antileukemic effect of ampelopsin was associated with the downregulation of AKT and NF-κB signaling pathways. Moreover, ampelopsin suppressed the expression levels of leukemia stemness markers, such as Oct4, Sox2, CD44, and CD133. Taken together, our findings suggest that ampelopsin may be an attractive chemotherapeutic agent against leukemia.

The Hallmarks of Flavonoids in Cancer

Flavonoids represent an important group of bioactive compounds derived from plant-based foods and beverages with known biological activity in cells. From the modulation of inflammation to the inhibition of cell proliferation, flavonoids have been described as important therapeutic adjuvants against several diseases, including diabetes, arteriosclerosis, neurological disorders, and cancer. Cancer is a complex and multifactor disease that has been studied for years however, its prevention is still one of the best known and efficient factors impacting the epidemiology of the disease. In the molecular and cellular context, some of the mechanisms underlying the oncogenesis and the progression of the disease are understood, known as the hallmarks of cancer. In this text, we review important molecular signaling pathways, including inflammation, immunity, redox metabolism, cell growth, autophagy, apoptosis, and cell cycle, and analyze the known mechanisms of action of flavonoids in cancer. The current literature provides enough evidence supporting that flavonoids may be important adjuvants in cancer therapy, highlighting the importance of healthy and balanced diets to prevent the onset and progression of the disease.

Dihydromyricetin Acts as a Potential Redox Balance Mediator in Cancer Chemoprevention

Dihydromyricetin (DHM) is a flavonoid extracted from the leaves and stems of the edible plant Ampelopsis grossedentata that has been used for Chinese Traditional Medicine. It has attracted considerable attention from consumers due to its beneficial properties including anticancer, antioxidative, and anti-inflammatory activities. Continuous oxidative stress caused by intracellular redox imbalance can lead to chronic inflammation, which is intimately associated with the initiation, promotion, and progression of cancer. DHM is considered a potential redox regulator for chronic disease prevention, and its biological activities are abundantly evaluated by using diverse cell and animal models. However, clinical investigations are still scanty. This review summarizes the current potential chemopreventive effects of DHM, including its properties such as anticancer, antioxidative, and anti-inflammatory activities, and further discusses the underlying molecular mechanisms of DHM in cancer chemoprevention by targeting redox balance and influencing the gut microbiota.

Microglial Annexin A3 promoted the development of melanoma via activation of hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway

BACKGROUND

Melanoma, a relatively common malignancy, has become one of the tumors with the fastest rising incidence in recent years. The purpose of this study was to investigate the effect of Microglial Annexin A3 (ANXA3) on melanoma.

METHODS

Serum samples were obtained from 20 patients with melanoma or 20 healthy controls. Kaplan-Meier survival analysis was performed. Transcriptome were used to analyze the correlation between ANXA3 expression and overall survival in patients with melanoma. Human melanoma cell lines WM-115 cells were transfected with ANXA3, si-ANXA3, ANXA3 + si-hypoxia inducible factor-1α (HIF-1α), si-ANXA3 + HIF-1α, and negative plasmids. Cell proliferation assay, cell invasion assay, and wound healing assay were performed on WM-115 cells. Lactate dehydrogenase (LDH) and caspase-3/9 activities were detected by commercial kits. Western blot and RT-PCR were used to detect the protein and mRNA expression of relation factors.

RESULTS

ANXA3 expression was up-regulated in patients with melanoma in comparison with healthy controls. Over-expression of ANXA3 promoted cell growth and migration, and reduced cytotoxicity of WM-115 cells. Overall survival (OS) and disease-free survival (DFS) of patients with high ANXA3 expression were both lower than those of patients with low ANXA3 expression. Down-regulation of ANXA3 reduced cell growth and migration, and promoted cytotoxicity of WM-115 cells. ANXA3 induced vascular endothelial growth factor (VEGF) signaling pathway by activation of HIF-1α.

CONCLUSION

In conclusion, our results indicated that ANXA3 promoted cell growth and migration of melanoma via activation of HIF-1α/VEGF signaling pathway.

Molecular Level Insight Into the Benefit of Myricetin and Dihydromyricetin Uptake in Patients With Alzheimer's Diseases

Alzheimer's disease (AD) is a neurodegenerative disease with a high incidence rate and complicated pathogenesis. Currently, all anti-AD drugs treat the symptoms of the disease, and with currently no cure for AD. Flavonoid containing natural products, Myricetin (MYR) and Dihydromyricetin (DMY), are abundant in fruits and vegetables, and have been approved as food supplements in some countries. Interestingly, MYR and DMY have been reported to have anti-AD effects. However, the underlying anti-AD mechanism of action of MYR and DMY is complex with many facets being identified. In this review, we explore the benefit of MYR and DMY in AD patients from a molecular level. Their mechanism of action are discussed from various aspects including amyloid β-protein (Aβ) imbalance, neuroinflammation, dyshomeostasis of metal ions, autophagy disorder, and oxidative stress.

Polyphenol-Mediated Autophagy in Cancer: Evidence of In Vitro and In Vivo Studies

One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants.

Inhibitory effect of dihydromyricetin on the proliferation of JAR cells and its mechanism of action

Dihydromyricetin (DMY) is a novel natural drug with antitumor activity against some cancer cells without obvious toxicity. Previously, its apoptotic effect on human choriocarcinoma was detected. The present study further investigated the therapeutic potential of DMY as a new drug for the treatment of choriocarcinoma, as well as its anti-proliferative effect and mechanism of action. The short-term proliferation of JAR cells was determined by MTT assay, whereas the effect of DMY on long-term cell proliferation was determined by colony forming assay. Flow cytometry was used to detect changes in the cell cycle. Furthermore, western blotting was used to detect the expression levels of proliferation-associated proteins such as cyclin A1, cyclin D1, SMAD3 and SMAD4. Reverse transcription-quantitative PCR (RT-qPCR) was used to quantify mRNA expression levels. The results indicated that DMY inhibited short and long-term proliferation of JAR cells in a concentration-dependent manner. Flow cytometry demonstrated S/G₂/M cell cycle arrest, and western blotting revealed the downregulation of SMAD3, SMAD4, cyclin A1 and cyclin D1 expression levels. The results of RT-qPCR and western blotting were consistent. Overall, the findings of the present study suggest that DMY inhibits the proliferation of human choriocarcinoma JAR cells, potentially through cell cycle arrest via the downregulation of cyclin A1, cyclin D1, SMAD3 and SMAD4 expression levels.

Marein protects human nucleus pulposus cells against high glucose-induced injury and extracellular matrix degradation at least partly by inhibition of ROS/NF-κB pathway

Intervertebral disc degeneration (IDD), a major cause of discogenic low back pain, is a musculoskeletal disorder involving the apoptosis of nucleus pulposus cells (NPCs) and extracellular matrix (ECM) degradation. Marein is a major active flavonoid ingredient extracted from the hypoglycemic plant Coreopsis tinctoria with several beneficial biological activities including anti-diabetic effects. Nevertheless, there are no reports concerning the effects of marein on IDD. Our study aimed to evaluate the effects of marein on high glucose (HG)-induced injury and ECM degradation in human NPCs (HNPCs). CCK-8 assay was applied to evaluate cell viability. Flow cytometry analysis, a cell death detection ELISA, and caspase-3 activity assay were used to assess apoptosis. The mRNA expression of ECM-related proteins matrix metalloproteinase (MMP)-3, MMP-13, Collagen II, and aggrecan were determined by qRT-PCR. The changes of the nuclear factor-kappa B (NF-κB) pathway were examined by western blot. Stimulation with HG significantly reduced cell viability and induced apoptosis in HNPCs. Moreover, HG exposure increased MMP-3 and MMP-13 expression and decreased Collagen II and aggrecan expression in HNPCs. Notably, marein effectively alleviated HG-induced viability reduction, apoptosis and ECM degradation in HNPCs. We also found that marein inhibited HG-induced ROS generation and NF-κB activation in HNPCs. Inhibition of NF-κB pathway reinforced HG-induced injury and ECM degradation in HNPCs. In summary, marein protected HNPCs against HG-induced injury and ECM degradation at least partly by inhibiting the ROS/NF-κB pathway.

Dihydromyricetin: A review on identification and quantification methods, biological activities, chemical stability, metabolism and approaches to enhance its bioavailability

BACKGROUND

Dihydromyricetin (DMY) is an important plant flavonoid, which has received great attention due to its health-benefiting activities, including antioxidant, antimicrobial, anti-inflammatory, anticancer, antidiabetic and neuroprotective activities. DMY capsules have been sold in US as a nutraceutical supplement to prevent alcoholic hangovers. The major disadvantage associated with DMY is its chemical instability and poor bioavailability caused by the combined effects of its low solubility and poor membrane permeability. This limits its practical use in the food and pharmaceutical fields.

SCOPE AND APPROACH

The present paper gives an overview of the current methods for the identification and quantification of DMY. Furthermore, recent findings regarding the main biological properties and chemical stability of DMY, the metabolism of DMY as well as different approaches to increase DMY bioavailability in both aqueous and lipid phases are discussed.

KEY FINDINGS AND CONCLUSIONS

Current trends on identification and quantification of DMY have been focused on spectral and chromatographic techniques. Many factors such as heat, pH, metal ions, could affect the chemical stability of DMY. Despite the diverse biological effects of DMY, DMY faces with the problem of poor bioavailability. Utilization of different delivery systems including solid dispersion, nanocapsule, microemuslion, cyclodextrin inclusion complexes, co-crystallization, phospholipid complexes, and chemical or enzymatic acylation has the potential to improve both the solubility and bioavailability. DMY digested in laboratory animals undergoes reduction, dehydroxylation, methylation, glucuronidation, and sulfation. Novel DMY delivery systems and basic pharmacokinetic studies of encapsulated DMY on higher animals and humans might be required in the future.

Dihydromyricetin induced lncRNA MALAT1-TFEB-dependent autophagic cell death in cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the second most common skin cancer. Dihydromyricetin (DHM), a Rattan tea extract, has been shown to have antitumor activity with no obvious toxicity to normal cells in vitro and in vivo. However, its efficacy in the treatment of CSCC and the underlying antitumor mechanism has not been fully elucidated yet. In our study, DHM increased autophagic flux in the A431 cells, as evidenced by the upregulation of LC3-II and downregulation of P62/SQSTM1. Moreover, the pharmacological or genetic blocking autophagy decreased DHM-induced cell death, indicating DHM triggered autophagic cell death in A431 cells. Specifically, DHM induced TFEB^(Ser142) de-phosphorylation, activated TFEB nuclear translocation and increased of TFEB reporter activity, which contributed to the expression of autophagy-related genes and subsequent initiated autophagic cell death in A431 cells. Importantly, DHM decreased lncRNA MALAT1 expression and MALAT1 overexpression abrogated the effects of DHM on TFEB-dependent autophagy both in vitro and in vivo. Taken together, DHM induces CSCC cell death via inducing excessive autophagy, which is mediated through the MALAT1-TFEB pathway. Therefore, DHM may be beneficial for the development of chemotherapy for CSCC.

Dihydromyricetin Ameliorates Cardiac Ischemia/Reperfusion Injury through Sirt3 Activation

During myocardial infarction, quickly opening the occluded coronary artery is a major method to save the ischemic myocardium. However, it also induces reperfusion injury, resulting in a poor prognosis. Alleviating the reperfusion injury improves the prognosis of the patients. Dihydromyricetin (DHM), a major component in the Ampelopsis grossedentata, has numerous biological functions. This study aims to clarify the effects of DHM under the ischemia/reperfusion (I/R) condition. We elucidated the role of Sirt3 in the cardiomyocyte response to DHM based on the hearts and primary cardiomyocytes. Cardiac function, mitochondrial biogenesis, and infarct areas were examined in the different groups. We performed Western blotting to detect protein expression levels after treatments. In an in vitro study, primary cardiomyocytes were treated with Hypoxia/Reoxygenation (H/R) to simulate the I/R. DHM reduced the infarct area and improved cardiac function. Furthermore, mitochondrial dysfunction was alleviated after DHM treatment. Moreover, DHM alleviated oxidative stress indicated by decreased ROS and MnSOD. However, the beneficial function of DHM was abolished after removing the Sirt3. On the other hand, the mitochondrial function was improved after DHM intervention in vitro study. Interestingly, Sirt3 downregulation inhibited the beneficial function of DHM. Therefore, the advantages of DHM are involved in the improvement of mitochondrial function and decreased oxidative stress through the upregulation of Sirt3. DHM offers a promising therapeutic avenue for better outcome in the patients with cardiac I/R injury.

MicroRNA-34a Promotes Renal Fibrosis by Downregulation of Klotho in Tubular Epithelial Cells

Renal fibrosis is the main pathological characteristic of chronic kidney disease (CKD), whereas the underlying mechanisms of renal fibrosis are not clear yet. Herein, we found an increased expression of microRNA-34a (miR-34a) in renal tubular epithelial cells of patients with renal fibrosis and mice undergoing unilateral ureteral obstruction (UUO). In miR-34a^-/- mice, miR-34a deficiency attenuated the progression of renal fibrosis following UUO surgery. The miR-34a overexpression promoted epithelial-to-mesenchymal transition (EMT) in cultured human renal tubular epithelial HK-2 cells, which was accompanied by sharp downregulation of Klotho, an endogenous inhibitor of renal fibrosis. Luciferase reporter assay revealed that miR-34a downregulated Klotho expression though direct binding with the 3' UTR of Klotho. Conversely, overexpression of Klotho prevented miR-34a-induced EMT in HK-2 cells. Furthermore, results showed that miR-34a was induced by transforming growth factor β1 (TGF-β1) through p53 activation, whereas dihydromyricetin could inhibit TGF-β1-induced miR-34a overexpression. Accordingly, dihydromyricetin administration dramatically restored the aberrant upregulation of miR-34a and Klotho reduction in obstructed kidney, and markedly ameliorated renal fibrosis in the Adriamycin nephropathy and UUO model mice. These findings suggested that miR-34a plays an important role in the progression of renal fibrosis, which provides new insights into the pathogenesis and treatment of CKD.

Protective effect of dihydromyricetin revents fatty liver through nuclear factor‑κB/p53/B‑cell lymphoma 2‑associated X protein signaling pathways in a rat model

Dihydromyricetin is the major flavonoid in vine tea, whose pharmacological action has attracted increasing attention in recent years. The triglyceride, albumin (ALB), alanine aminotransferase, aspartate aminotransferase, malondialdehyde, superoxide dismutase, glutathione (GSH), GSH peroxidase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-18 expression levels were measured using enzyme-linked immunosorbent assay kits. The protein levels of ALB and collagen I, PPARα, NF-κB, p53 and Bax were used to measure using western blotting. The results revealed that dihydromyricetin prevented the development of fatty liver, and inhibited oxidative stress, inflammation and apoptosis in a fatty liver rat model. In addition, treatment with dihydromyricetin inhibited the levels of ALB and collagen I, while it induced peroxisome proliferator-activated receptor α protein expression. Dihydromyricetin also suppressed the protein expression levels of nuclear factor (NF)-κB, p53 and B-cell lymphoma 2-associated X protein (Bax) in the rat model. Collectively, it is concluded that dihydromyricetin exerted a protective effect on fatty liver through NF-κB/p53/Bax signaling pathways in a rat model.

Dihydromyricetin from ampelopsis grossedentata protects against vascular neointimal formation via induction of TR3

Vine tea has been used as a medicinal herb in traditional Chinese medicine for hundreds of years. As the most abundant ingredient in vine tea, Dihydromyricetin (DHM) has been reported to exert anti-inflammatory, antioxidant, and anti-cardiovascular disease. However, the role of DHM in injury-induced neointimal formation remains poorly characterized. We determined the effects of DHM on ligation-induced carotid artery neointimal formation. We found that ligation-induced carotid artery neointimal formation could be significantly attenuated by DHM treatment. We provide evidence that DHM increases orphan nuclear receptor TR3 expression in smooth muscle cell (SMC) and carotid artery. Moreover, overexpression and loss-of-function strategies of TR3 were done to overexpression and knockdown of TR3, and demonstrate that DHM promotes SMC differentiation, however, inhibits SMC proliferation and migration, via regulating expression of TR3. Collectively, we reveal that DHM may be a therapeutic agent for the treatment of injury-induced vascular diseases.

Recent Update on the Pharmacological Effects and Mechanisms of Dihydromyricetin

As the most abundant natural flavonoid in rattan tea, dihydromyricetin (DMY) has shown a wide range of pharmacological effects. In addition to the general characteristics of flavonoids, DMY has the effects of cardioprotection, anti-diabetes, hepatoprotection, neuroprotection, anti-tumor, and dermatoprotection. DMY was also applied for the treatment of bacterial infection, osteoporosis, asthma, kidney injury, nephrotoxicity and so on. These effects to some extent enrich the understanding about the role of DMY in disease prevention and therapy. However, to date, we still have no outlined knowledge about the detailed mechanism of DMY, which might be related to anti-oxidation and anti-inflammation. And the detailed mechanisms may be associated with several different molecules involved in cellular apoptosis, oxidative stress, and inflammation, such as AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), protein kinase B (Akt), nuclear factor-κB (NF-κB), nuclear factor E2-related factor 2 (Nrf2), ATP-binding cassette transporter A1 (ABCA1), peroxisome proliferator-activated receptor-γ (PPARγ) and so on. Here, we summarized the current pharmacological developments of DMY as well as possible mechanisms, aiming to push the understanding about the protective role of DMY as well as its preclinical assessment of novel application.

Protective effect of dihydromyricetin on LPS-induced acute lung injury

Dihydromyricetin (DHM), a bioactive flavonoid component isolated from Ampelopsis grossedentata, is known to have anti-inflammatory effect, but the effect of DHM on acute lung injury (ALI) is largely unknown. Here, we investigated the effect of DHM on ALI and the underlying mechanism by bioinformatic analyses and animal experiments. We found that pretreatment with DHM ameliorated lung pathological changes and suppressed the inflammation response in lung tissues after LPS challenge. The potential targets of DHM were predicted by DDI-CPI and DRAR-CPI tools and analyzed using the STRING server to predict the functionally related signaling pathways, such as MAPK signaling. Molecular docking calculations indicated that DHM could be embedded tightly into the binding pocket of ERK, JNK, and p38. Furthermore, the activation of MAPK signaling induced by LPS was inhibited by DHM. In conclusion, these findings suggest that DHM may exert its protective effect on ALI by inhibiting MAPK signaling. The present study supports a potential clinical application for DHM in treating ALI and provides a novel design that combines in silico methods with in vivo experiments for drug research.

Dihydromyricetin Protects against Bone Loss in Ovariectomized Mice by Suppressing Osteoclast Activity

Dihydromyricetin (DMY), the main flavonoid component of Ampelopsis grossedentata, possesses pharmacological activities useful for treatment of diseases associated with inflammation and oxidative damage. Because osteoclasts are often involved in chronic low-grade systemic inflammation and oxidative damage, we hypothesized that DMY may be an effective treatment for osteoclast-related diseases. The effects of DMY on osteoclast formation and activity were examined in vitro. Female C57BL/6 mice were ovariectomized to mimic menopause-induced bone loss and treated with DMY, and femur samples were subjected to bone structure and histological analysis, serum biochemical indicators were also measured. DMY suppressed the activation of nuclear factor-κB, c-Fos and mitogen-activated protein kinase, and prevented production of reactive oxygen species. DMY decreased expression of osteoclast-specific genes, including Trap, Mmp-9, Cathepsin K, C-Fos, Nfatc1, and Rank. In addition, DMY prevented bone loss and decreased serum levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6, and with a decrease in the ratio between receptor activator of nuclear factor-κB (RANK) ligand (RANKL) and osteoprotegerin (OPG) in vivo. These findings demonstrate that DMY attenuates bone loss and inhibits osteoclast formation and activity through modulation of multiple pathways both upstream and downstream of RANKL signaling. DMY may thus be a useful option for treatment of osteoclast-related diseases such as rheumatoid arthritis and osteoporosis.

Inhibition of autophagy enhances synergistic effects of Salidroside and anti-tumor agents against colorectal cancer

Background

Various plant extracts have been suggested to be used as auxiliary agents in chemotherapy considering their anti-proliferative effect on cancer cells. However, recent reports reveal that plant extracts may function as inducers of autophagy of cancer cells. In general, autophagy confers survival advantage for cells responding to stress conditions, thus representing an important mechanism for chemo-resistance. This study was aimed to investigate the effectiveness of combined use of Salidroside (Sal, a phenylpropanoid glycosides from Rhodiola rosea L) with anti-tumor agents against colorectal cancer (CRC) cells, and moreover to evaluate the potential role of autophagy in the combined therapy.

Methods

CRC cells, HCT-116, were incubated with Sal alone or in combination with conventional chemotherapy agents including oxaliplatin (OXA), 5-fluorouracil (5-FU) and Doxorubicin (ADM). Cell proliferative characteristics were evaluated by cell viability and apoptosis rate. The protein expression was assessed by Immunofluorescent and Western blot assays.

Results

Sal, alone or in combination with anti-tumor agents, increased expression of autophagic biomarkers, including LC3B and Becline-1, suggesting an autophagy induction. Except for the up-regulation of p-AMPK, p-mTOR, p-NF-κB (p65), TGF-β, p-JAK2 and p-STAT3 were down-regulated by Sal. Because autophagy is positively correlated with the activation of AMPK/mTOR, NF-κB, TGFβ1 and JAK2/STAT3 cascades, the autophagy induced by Sal may associate with AMPK activation. Indeed, blockage of AMPK signaling via Compound C or AMPK knockdown inhibited the autophagy. The blockage of AMPK signaling or a direct inhibition of autophagy via 3-MA increased effectiveness of combined use of Sal with anti-tumor agents against CRC.

Conclusions

Inhibition of autophagy enhances synergistic effects of Sal and anti-tumor agents against colorectal cancer. This study provides experimental evidence and theoretical reference for improvement of a novel chemotherapy treatment protocol.

The Versatile Effects of Dihydromyricetin in Health

Dihydromyricetin is a flavonoid isolated from Ampelopsis grossedentata, which is traditionally used in China. Dihydromyricetin exhibits health-benefiting activities with minimum adverse effects. Dihydromyricetin has been demonstrated to show antioxidative, anti-inflammatory, anticancer, antimicrobial, cell death-mediating, and lipid and glucose metabolism-regulatory activities. Dihydromyricetin may scavenge ROS to protect against oxidative stress or potentiate ROS generation to counteract cancer cells selectively without any effects on normal cells. However, the low bioavailability of dihydromyricetin limits its potential applications. Recent research has gained positive and promising data. This review will discuss the versatile effects and clinical prospective of dihydromyricetin.