Progressive study of effects of erianin on anticancer activity

Potential Action Mechanism of Erianin in Relieving MNNG-triggered Chronic Atrophic Gastritis

Chronic atrophic gastritis (CAG) is a critical initial step in gastric cancer tumorigenesis accompanied by high malignancy. Erianin has been proposed as a promising agent in treating precancerous lesions of gastric cancer. Considering that little work has been implemented concerning the specific role and possible regulatory mechanism of Erianin in CAG, the goal of the study is to disclose the effects and mechanism of erianin on the malignant transformation in the process of CAG. CAG cell model was generated in human gastric epithelium GES-1 cells induced by Nmethyl-N'-nitro-N-nitrosoguanidine (MNNG). CCK-8 method determined cell viability. ELISA and corresponding assay kits severally appraised the contents of inflammatory cytokines and oxidative stress markers. Cellular reactive oxygen species (ROS) formation was measured by flow cytometry analysis using DCFH-DA probe. GFP-LC3 immunofluorescence staining and Western blotting evaluated autophagy. Also, Western blotting analyzed the expression of components in mitogen activated protein kinase (MAPK)/mechanistic target of rapamycin (mTOR) signaling. The results manifested that MNNG treatment diminished the viability and autophagy whereas intensified the inflammation and oxidative stress in GES-1 cells, which were all reversed by Erianin. Besides, Erianin blocked mTOR/MAPK signaling in MNNG-exposed GES-1 cells. Autophagy inhibitor 3-methyladenine (3-MA) or p38 MAPK agonist asiatic acid partially counteracted the protection elicited by Erianin against viability loss, inflammatory reaction as well as oxidative stress in MNNG-induced GES-1 cells. Combined with the findings, Erianin might mediate autophagy to improve MNNG-elicited CAG via MAPK/mTOR signaling.

Natural products targeting RAS by multiple mechanisms and its therapeutic potential in cancer: An update since 2020

RAS proteins, as pivotal signal transduction molecules, are frequently mutated and hyperactivated in various human cancers, closely associated with tumor cell proliferation, survival, and metastasis. Despite extensive research on RAS targeted therapies, developing effective RAS inhibitors remains a significant challenge. Natural products, endowed with unique chemical structures and diverse biological activities through long-term natural selection, have emerged as a vital resource for discovering novel RAS-targeted therapeutic drugs. This review focuses on the latest advancements in targeting RAS with natural products and categorizes these natural products based on their mechanisms of action. Additionally, we discuss the challenges faced by these natural products during clinical translation, including issues related to pharmacokinetics. Strategies such as combination therapy, structural optimization, and drug delivery systems are anticipated to enhance efficacy and overcome these challenges.

Erianin inhibits the progression of DDP-resistant lung adenocarcinoma by regulating the Wnt/β-catenin pathway and activating the caspase-3 for apoptosis in vitro and in vivo

BACKGROUND

Platinum-based chemotherapy is one of the main treatments for lung adenocarcinoma (LUAD). However, the toxic side effects and drug resistance of chemotherapeutic drugs on normal cells are still a thorny problem in clinical treatment. Dendrobium is one of the three largest genera of Orchidaceous family, which has ornamental and medicinal value. Dendrobium is mainly distributed in the tropics and subtropics of South Asia, Oceania and other regions, with 1547 species of Dendrobium currently known. In China, "Shi hu" and "Tie pi shi hu" are well-known traditional medicines and have been included in the Chinese Pharmacopoeia (Editorial Board of Chinese Pharmacopoeia, 2020). Erianin is a natural product isolated from Dendrobium and is considered as a potential anticancer molecule due to its remarkable anti-tumor effects through various mechanisms, among which induced cancer cell apoptosis, inhibited invasion and migration. This study preliminarily explored the mechanism of Erianin inhibiting the progression of cisplatin (DDP) resistant LUAD in vivo and in vitro.

METHODS

The effect of Erianin on the proliferation of DDP-resistant LUAD cells was detected by CCK-8 assay, wound healing assay and cloning assay. Transwell assay was used to evaluate the effect of Erianin on cell invasion and migration. The changes of cell cycle and apoptosis were detected by flow cytometry and TUNEL assay. Finally, the effects of Erianin on cell function and signaling pathway-related protein expression in vivo and in vitro were examined based on the enrichment analysis.

RESULTS

Erianin could inhibit the proliferation, invasion and migration, induce apoptosis, altered cell cycle of DDP-resistant LUAD cells, and reverse the resistance to DDP. Western blotting results showed that Erianin exerted its anti-tumor effects by regulating the Wnt/β-catenin cascade in DDP-resistant LUAD cells.

CONCLUSION

Erianin may exerted its anti-tumor effect in DDP-resistant LUAD cells by regulating the Wnt3/β-Catenin/Survivin/Bcl-2/Caspase-3/Cyclin D1 axis.

Research progress on the regulatory and pharmacological mechanism of chemical components of Dendrobium

Dendrobium is a precious Chinese herbal medicine, which belongs to the genus Orchidaceae. Ancient records and modern pharmacological research show that Dendrobium has pharmacological effects such as anti-tumor, antioxidant regulating immunity and blood glucose, and anti-aging. Dendrobium contains polysaccharides, alkaloids, bibenzyl, sesquiterpenes, phenanthrene, polyphenols and other types of chemicals. Its pharmacological activity is closely related to these chemical components. For example, dendrobium extracts can achieve anti-tumor effects by inhibiting tumor cell proliferation and metastasis, promoting cell apoptosis and ferroptosis, or increasing cell sensitivity to chemotherapy drugs. It enhances immunity by regulating immune cell activity or cytokine release. In addition, it can alleviate neurodegenerative diseases by protecting nerve cells from apoptotic damage. In recent years, research reports on biologically active compounds in Dendrobium have shown a blowout growth, which makes us realize that it is meaningful to continuously update the research progress on the components and pharmacological regulatory mechanism of this traditional Chinese medicine. By classifying the collected chemical components according to different chemical structures and summarizing their pharmacological mechanisms, we investigated the current research progress of Dendrobium and provide a more comprehensive scientific foundation for the further development and clinical transformation of Dendrobium in the future.

Integrated metabolomic and transcriptomic analyses of Dendrobium chrysotoxum and D. thyrsiflorum reveal the biosynthetic pathway from gigantol to erianin

Erianin is one of the most representative bibenzyls with significant inhibitory activity against a wide range of tumor cells. However, the low erianin level in natural materials has severely inhibited its further development in health care. Our aim was to uncover the erianin biosynthetic pathway to lay the foundation for promoting its production. Firstly, we screened and obtained two Dendrobium species (Dendrobium thyrsiflorum stems with lower erianin content and D. chrysotoxum stems with higher erianin content), belonging to the same Dendrobium section (Chrysotoxae). A systematic analysis of bibenzyl structure and content in two stems revealed that gigantol might be an erianin biosynthetic intermediate, which was verified by introducing deuterium-labeled gigantol. Chemical structure analyses indicated that gigantol was modified by two kinds of enzymes (hydroxylases and O-methyltransferases), leading to erianin synthesis. Up-regulated hydroxylases and O-methyltransferases (OMTs) were screened out and were performed by molecular docking simulation experiments. We propose a rational biosynthetic pathway from gigantol to erianin, as well as relevant enzymes involved in the process. Our findings should significantly contribute to comprehensive resolution of the erianin biosynthetic pathway, promote its large-scale industrial production as well as contribute to biosynthesis studies of other bibenzyls.

Erianin Impedes the Proliferation and Metastatic Migration Through Suppression of STAT-3 Phosphorylation in Human Esophageal Cancer Cells

In this study, we have investigated erianin, a natural phenolic drug that impedes proliferation and metastatic migration through suppression of STAT-3 phosphorylation in human esophageal cancer cells. Eca-109 cells were treated with different concentrations of erianin (4, 8, 12 µM) for 24 h, and then cell proliferation, apoptosis, and metastatic markers were evaluated. Erianin-induced cytotoxicity and cell proliferation were examined using MTT and crystal violet staining techniques. The measurement of reactive oxygen species (ROS) and the study of apoptotic changes were conducted through flow cytometry. Furthermore, protein expression analyses via western blotting included an evaluation of JAK-STAT3, cell survival, cell cycle, proliferation, and apoptosis-related proteins. Moreover, erianin treatment-associated MMP expressions were studied by RT-PCR. In this study, erianin treatment induces substantial cytotoxicity and ROS production based on the concentrations in Eca-109 cells. Moreover, erianin inhibits the MAPK phosphorylation, proliferation, and metastatic protein in Eca-109 cells. STAT-3 is a crucial transcriptional factor that regulates numerous downstream proteins, such as proliferation, anti-apoptosis, and metastatic proteins. In this study, erianin treatment inhibited the protein expression of IL-6, IL-10, JAK-1, and p-STAT-3 expressions leading to induce apoptosis in Eca-109 cells. Moreover, erianin inhibited the expression of proliferation, metastatic, and anti-apoptotic markers in Eca-109 cells. Hence, erianin suppressed the JAK/STAT-3 signaling pathway and demonstrates potential as a chemotherapeutic agent for the treatment of esophageal cancer.

The cytotoxic natural compound erianin binds to colchicine site of β-tubulin and overcomes taxane resistance

Erianin, a natural compound derived from Dendrobium, has shown significant anticancer properties against a wide range of cancer cells. Despite the identification of multiple mechanisms of action for erianin, none of these mechanisms fully account for its broad-spectrum effect. In this study, we aimed to identify the cellular target and underlying mechanism responsible for the broad-spectrum antitumor effects of erianin. We found that erianin effectively inhibited tubulin polymerization in cancer cells and purified tubulin. Through competition binding assays and X-ray crystallography, it was revealed that erianin bound to the colchicine site of β-tubulin. Importantly, the X-ray crystal structure of the tubulin-erianin complex was solved, providing clear insight into the orientation and position of erianin in the colchicine-binding site. Erianin showed activity against paclitaxel-resistant cells, evidenced by G2/M cell cycle arrest, apoptosis-related PARP and Caspase-3 cleavage, and in vivo xenograft studies. The study concluded that erianin bound reversibly to the colchicine site of β-tubulin, inhibited tubulin polymerization, and displayed anticancer activity against paclitaxel-resistant cells, offering valuable insights for further exploration as potential anticancer agents.

Discovery of the Natural Bibenzyl Compound Erianin in Dendrobium Inhibiting the Growth and EMT of Gastric Cancer through Downregulating the LKB1-SIK2/3-PARD3 Pathway

Erianin, a bibenzyl compound found in dendrobium extract, has demonstrated broad anticancer activity. However, its mechanism of action in gastric cancer (GC) remains poorly understood. LKB1 is a tumor-suppressor gene, and its mutation is an important driver of various cancers. Yet some studies have reported contradictory findings. In this study, we combined bioinformatics and in vitro and in vivo experiments to investigate the effect and potential mechanism of Erianin in the treatment of GC. The results show that LKB1 was highly expressed in patients' tumor tissues and GC cells, and it was associated with poor patient prognosis. Erianin could promote GC cell apoptosis and inhibit the scratch repair, migration, invasion, and epithelial-mesenchymal transition (EMT) characteristics. Erianin dose-dependently inhibited the expression of LKB1, SIK2, SIK3, and PARD3 but had no significant effect on SIK1. Erianin also inhibited tumor growth in CDX mice model. Unexpectedly, 5-FU also exhibited a certain inhibitory effect on LKB1. The combination of Erianin and 5-FU significantly improved the anti-tumor efficacy of 5-FU in the growth of GC cells and xenograft mouse models. In summary, Erianin is a potential anti-GC compound that can inhibit GC growth and EMT properties by targeting the LKB1-SIK2/3-PARD3-signaling axis. The synergistic effect of Erianin and 5-FU suggests a promising therapeutic strategy for GC treatment.

Erianin promotes apoptosis and inhibits Akt-mediated aerobic glycolysis of cancer cells

Highly activated aerobic glycolysis provides the metabolic requirements for tumor cell growth and proliferation. Erianin, a natural product isolated from Dendrobium chrysotoxum Lindl, has been reported to exert antitumor activity in multiple cancers. However, whether Erianin exerts inhibitory effects on aerobic glycolysis and the inherent mechanism remain poorly defined in non-small cell lung cancer (NSCLC). Here, we showed that Erianin inhibited the cell viability and proliferation, and induced apoptosis in NSCLC cells. Moreover, Erianin overtly suppressed aerobic glycolysis via decreasing HK2 expression. Mechanistically, Erianin dose-dependently curbed the Akt-GSK3β signaling pathway phosphorylation activation, which afterwards downregulated HK2 expression. Meanwhile, Erianin inhibited HCC827 tumor growth in vivo. Taken together, our results suggest that the natural product Erianin can suppress aerobic glycolysis and exert potent anticancer effects via the Akt-GSK3β signaling pathway in NSCLC cells.

Erianin promotes endogenous neurogenesis in traumatic brain injury rats

The objective of this study was to explore the positive influence and potential mechanism of Erianin on the recovery of brain cells following a traumatic brain injury (TBI). TBI rat models were prepared and treated with Erianin injection via tail vein. The assessment included evaluating the rats' levels of oxidative stress, inflammation, neuronal damage, mitochondrial damage, neuronal regeneration, transformation of pro-inflammatory microglial cells, activation status of the ERK signal pathway, and the functionality of their learning and memory. After administering Erianin, there was a suppression of oxidative stress, inflammation, nerve cell damage, and mitochondrial damage in the TBI rats. Additionally, there was an increase in neuronal regeneration in the cortex and hippocampus, inhibition of pro-inflammatory microglial cell transformation in the cortex, improvement in learning and memory function in TBI rats, and simultaneous inhibition of the activation of the ERK1/c-Jun signal pathway. The findings suggest that Erianin has the potential to reduce oxidative stress and inflammatory reaction in rats with TBI, safeguard nerve cells against apoptosis, stimulate the growth of new neural cells, ultimately enhancing the cognitive abilities and memory function of the rats. The inhibition of the ERK signaling pathway could be closely associated with these effects.

Erianin suppressed lung cancer stemness and chemotherapeutic sensitivity via triggering ferroptosis

The previous research has focused on the suppressive effects of Erianin on tumor progression, but its impact on cancer stemness has not been reported. This study aimed to investigate the effects of Erianin on lung cancer stemness. First, we screened various concentrations Erianin to ensure that it did not affect lung cancer cell viability. Subsequently, we found that Erianin significantly attenuated lung cancer stemness through various analyses, including qRT-PCR, western blot, sphere-formation, and ALDH activity detection. Furthermore, Erianin was shown to enhance chemosensitivity of lung cancer cells. Mechanistically, three inhibitors (cell apoptosis inhibitor, necrosis inhibitor, and ferroptosis inhibitor) were added into lung cancer cells with Erianin treatment, respectively, and we found that Erianin mainly suppressed lung cancer stemness through ferroptosis. Taken together, this study reveals that Erianin has the potential to suppress lung cancer stemness and could be a valuable chemotherapeutic enhancer for lung cancer.

Novel Insights on Ferroptosis Modulation as Potential Strategy for Cancer Treatment: When Nature Kills

Significance: The multifactorial nature of the mechanisms implicated in cancer development still represents a major issue for the success of established antitumor therapies. The discovery of ferroptosis, a novel form of programmed cell death distinct from apoptosis, along with the identification of the molecular pathways activated during its execution, has led to the uncovering of novel molecules characterized by ferroptosis-inducing properties. Recent advances: As of today, the ferroptosis-inducing properties of compounds derived from natural sources have been investigated and interesting findings have been reported both in vitro and in vivo. Critical Issues: Despite the efforts made so far, only a limited number of synthetic compounds have been identified as ferroptosis inducers, and their utilization is still limited to basic research. In this review, we analyzed the most important biochemical pathways involved in ferroptosis execution, with particular attention to the newest literature findings on canonical and non-canonical hallmarks, together with mechanisms of action of natural compounds identified as novel ferroptosis inducers. Compounds have been classified based on their chemical structure, and modulation of ferroptosis-related biochemical pathways has been reported. Future Directions: The outcomes herein collected represent a fascinating starting point from which to take hints for future drug discovery studies aimed at identifying ferroptosis-inducing natural compounds for anticancer therapies. Antioxid. Redox Signal. 40, 40-85.

Recent advances of antitumor leading compound Erianin: Mechanisms of action and structural modification

Erianin, a bioactive compound extracted from Dendrobium, a traditional Chinese medicine, exhibits remarkable anti-cancer properties through diverse molecular mechanisms and has attracted the attention of medicinal chemists. However, the low solubility in water, rapid metabolism and elimination from the body lead to poor bioavailability of Erianin, and greatly hinder its clinical application. The development of new Erianin derivatives is continuously proceed to improve its anticancer effects. In recent years, although important progress in the development of Erianin and the publication of some reviews in this aspect, the mechanism against various cancers, pharmacokinetic study, structural modification as well as structure-activity relationships have not been thoroughly considered. This review is aimed at providing complete picture regarding the above aspects by reviewing studies from 2000 to 2023.06. This review also supplies some important viewpoints on the design and future directions for the development of Erianin derivatives as possible clinically effective anticancer agents.

Erianin alleviates collagen-induced arthritis in mice by inhibiting Th17 cell differentiation

Rheumatoid arthritis (RA) is a chronic autoimmune disorder. Its pathogenesis is complicated but highly related to aberrant Th17 overactivation. Uncontrolled Th17 cell expansion and activation in populations and associated activities contribute to the progression of RA. Although clinical RA remedies are available, not all RA patients respond to these treatments, and adverse effects are always a concerning issue during treatment. To expand the repertoire of possible anti-RA remedies, we chose the phytochemical compound erianin, isolated from Dendrobium sp., and evaluated its antiarthritic effect in vitro and in vivo. We found that erianin efficiently controlled the differentiation and activation of Th17 cell development from primary CD4 T cells, limiting IL-17A cytokine production and RORγT transcript generation. In line with molecular docking models, the essential signaling pathway for Th17 polarization, the JAK/STAT3 pathway, was inhibited upon erianin treatment, with dose-dependent inhibition of phosphorylation shown by western blotting. More importantly, erianin treatment reduced arthritic manifestations and proinflammatory cytokine levels in collagen-induced arthritis (CIA) mice, as well as protecting the joint histological microstructure. Overall, erianin revealed a promising inhibitory effect on Th17 overactivation and decreased disability in CIA mice. Therefore, erianin could be further developed as a candidate RA remedy.

Secondary Metabolomic Analysis and In Vitro Bioactivity Evaluation of Stems Provide a Comprehensive Comparison between Dendrobium chrysotoxum and Dendrobium thyrsiflorum

The stems of Dendrobium chrysotoxum (DC) are commonly used as health-promoting foods due to their excellent biological activities. However, the stems of D. thyrsiflorum (DT) are often used to meet the scarcity of DC in production because of their highly similar morphology. However, the related metabolomic and bioactive information on the stems of DC and DT are largely deficient. Here, secondary metabolites of DC and DT stems were identified using an ultra-performance liquid chromatography-electrospray ionization-mass spectrometry, and their health-promoting functions were evaluated using several in vitro arrays. A total of 490 metabolites were identified in two stems, and 274 were significantly different. We screened out 10 key metabolites to discriminate the two species, and 36 metabolites were determined as health-promoting constituents. In summary, DT stems with higher extract yield, higher total phenolics and flavonoids, and stronger in vitro antioxidant activities demonstrated considerable potential in food and health fields.

Erianin: A phytoestrogen with therapeutic potential

Erianin, a phytoestrogen with therapeutic potential, is one of the major active components of Dendrobll caulis. Erianin has a variety of pharmacological effects, such as anti-tumor, anti-inflammatory, anti-diabetic retinopathy, anti-psoriasis, and antibacterial effects. Especially, in regard to the anti-tumor effect of erianin, the underlying molecular mechanism has been partly clarified. In fact, the numerous pharmacological actions of erianin are complex and interrelated, mainly including ERK1/2, PI3K/Akt, JAK2/STAT3, HIF-1α/PD-L1, PPT1/mTOR, JNK/c-Jun, and p38 MAPK signal pathway. However, on account of the poor water solubility and the low bioavailability of erianin, greatly affected and limited its further development and application. And it is worthwhile and meaningful to explore more extensive pharmacological effects and mechanisms, clarify pharmacokinetics, and synthesize the derivatives of erianin. Conclusively, in this paper, the pharmacological effects of erianin and its mechanism, pharmacokinetics, and derivatives studies were reviewed, in order to provide a reference for the development and application of erianin.

Design, Synthesis, and Biological Evaluation of Histone Deacetylase Inhibitors Derived from Erianin and Its Derivatives

Multi-target histone deacetylase (HDAC) inhibitors can be designed by introducing dominant structures of natural products to enhance activity and efficacy while avoiding the toxicity from other targets. In this study, we reported a series of novel HDAC inhibitors based on erianin and amino erianin upon pharmacophore fusion strategy. Two representative compounds, N-hydroxy-2-(2-methoxy-5- (3,4,5-trimethoxyphenethyl)phenoxy)acetamide and N-Hydroxy-8-((2-methoxy-5- (3,4,5-trimethoxyphenethyl)phenyl)amino)octanamide, possessed good inhibitory effect against five cancer cells tested (IC50 =0.30-1.29 μΜ, 0.29-1.70 μΜ) with strong HDAC inhibition, and low toxicity toward L02 cells, which were selected for subsequent biological studies in PANC-1 cells. They were also found to promote the intracellular generation of reactive oxygen species, cause DNA damage, block the cell cycle at G2/M phase, and activate the mitochondria-related apoptotic pathway to induce cell apoptosis, which are significant for the discovery of new HDAC inhibitors.

Targeting the Interplay of Autophagy and ROS for Cancer Therapy: An Updated Overview on Phytochemicals

Autophagy is an evolutionarily conserved self-degradation system that recycles cellular components and damaged organelles, which is critical for the maintenance of cellular homeostasis. Intracellular reactive oxygen species (ROS) are short-lived molecules containing unpaired electrons that are formed by the partial reduction of molecular oxygen. It is widely known that autophagy and ROS can regulate each other to influence the progression of cancer. Recently, due to the wide potent anti-cancer effects with minimal side effects, phytochemicals, especially those that can modulate ROS and autophagy, have attracted great interest of researchers. In this review, we afford an overview of the complex regulatory relationship between autophagy and ROS in cancer, with an emphasis on phytochemicals that regulate ROS and autophagy for cancer therapy. We also discuss the effects of ROS/autophagy inhibitors on the anti-cancer effects of phytochemicals, and the challenges associated with harnessing the regulation potential on ROS and autophagy of phytochemicals for cancer therapy.

The roles of ERIANIN in tumor and innate immunity and its' perspectives in immunotherapy

Traditional Chinese medicine has been used in China for thousands of years. In 2022, the 14th Five-Year Plan for the Development of Traditional Chinese Medicine was released, aiming to enhance traditional Chinese medicine health services and improve policies and systems for high-quality traditional Chinese medicinal development by 2025. ERIANIN, the main component of the traditional Chinese medicine Dendrobium, plays an important role in anti-inflammatory, antiviral, antitumor, antiangiogenic, and other pharmacological effects. ERIANIN has broad-spectrum antitumor effects, and its tumor-suppressive effects have been confirmed in the study of various diseases, such as precancerous lesions of the stomach, gastric cancer, liver cancer, lung cancer, prostate cancer, bladder cancer, breast cancer, cervical cancer, osteosarcoma, colorectal cancer, leukaemia, nasopharyngeal cancer and melanoma through the multiple signaling pathways. Thus, the aim of this review was to systematically summarise the research on ERIANIN with the aim of serving as a reference for future research on this compound and briefly discuss some future perspectives development of ERIANIN in combined immunotherapy.

Anticancer natural products targeting immune checkpoint protein network

Normal cells express surface proteins that bind to immune checkpoint proteins on immune cells to turn them off, whereby the immune system does not attack normal healthy cells. Cancer cells can also utilize this same protective mechanism by expressing surface proteins that can interact with checkpoint proteins on immune cells to overcome the immune surveillance. Immunotherapy is making the best use of the body's own immune system to reinforce anti-tumor responses. The most generally used immunotherapy is the control of immune checkpoints including the cytotoxic T lymphocyte-associated molecule 4 (CTLA-4), programmed cell deathreceptor 1 (PD-1), or programmed cell death ligand-1 (PD-L1). In spite of the clinical effectiveness of immune checkpoint inhibitors, the overall response rate still remains low. Therefore, there have been considerable efforts in searching for alternative immune checkpoint proteins that may work as new therapeutic targets for treatment of cancer. Recent studies have identified several additional novel immune checkpoint targets, including lymphocyte activation gene-3, T cell immunoglobulin and mucin-domain containing-3, T cell immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain, V-domain Ig suppressor of T cell activation, B7 homolog 3 protein, B and T cell lymphocyte attenuator, and inducible T cell COStimulator. Natural compounds, especially those present in medicinal or dietary plants, have been investigated for their anti-tumor effects in various in vitro and in vivo models. Some phytochemicals exert anti-tumor activities based on immunoregulatioby blocking interaction between proteins involved in immune checkpoint signal transduction or regulating their expression/activity. Recently, synergistic anti-cancer effects of diverse phytochemicals with anti-PD-1/PD-L1 or anti-CTLA-4 monoclonal antibody drugs have been continuously reported. Considering an increasing attention to noteworthy therapeutic effects of immune checkpoint inhibitors in the cancer therapy, this review focuses on regulatory effects of selected phytochemicals on immune checkpoint protein network and their combinational effectiveness with immune checkpoint inhibitors targeting tumor cells.

Radiosynthesis and tumor microPET/CT imaging of 18F-fluoroethoxylerianin, a 18F-Labeled Erianin Analogue

Abstract: Erianin is an active constituent of Dendrobium candidum. In this work, 18F -fluoroethoxylerianin([18F]FEE), a 18F-Labeled Erianin analogue, was designed and synthesized to evaluate the property of Erianin and related analogues by in vivo PET imaging. The initial product was separated and purified by liquid phase separation module Explora LC and simple homemade solid phase extraction, and high purity [18F]FEE was finally obtained. The radiochemical purity of [18F]FEE was determined by Radio-TLC and Radio-HPLC. [18F]FEE showed good stability in normal saline and serum, and could be quickly eliminated from mice. Cell experiments, biological distribution, and small animal PET/CT further showed that [18F]FEE had a high uptake rate in HepG2 tumor cells, and showed good imaging ability in HepG2 tumor model. The results of this study indicate that the synthesized 18F-Labeled Erianin analogue is an effective new probe for positron emission tomography (PET) imaging of HepG2 hepatocellular carcinoma, which provides an intuitive and reliable theoretical basis for the development of erianin as an anticancer drug.

Anticancer Activity of Erianin: Cancer-Specific Target Prediction Based on Network Pharmacology

Erianin is a major bisbenzyl compound extracted from Dendrobium chrysotoxum Lindl., an important traditional Chinese herb. In recent years, a growing body of evidence has proved the potential therapeutic effects of erianin on various cancers, including hepatoma, melanoma, non-small-cell lung carcinoma, myelogenous leukemia, breast cancer, and osteosarcoma. Especially, the pharmacological activities of erianin, such as antioxidant and anticancer activity, have been frequently demonstrated by plenty of studies. In this study, we firstly conducted a systematic review on reported anticancer activity of erianin. All updated valuable information regarding the underlying action mechanisms of erianin in specific cancer was recorded and summarized in this paper. Most importantly, based on the molecular structure of erianin, its potential molecular targets were analyzed and predicted by means of the SwissTargetPrediction online server (http://www.swisstargetprediction.ch). In the meantime, the potential therapeutic targets of 10 types of cancers in which erianin has been proved to have anticancer effects were also predicted via the Online Mendelian Inheritance in Man (OMIM) database (http://www.ncbi.nlm.nih.gov/omim). The overlapping targets may serve as valuable target candidates through which erianin exerts its anticancer activity. The clinical value of those targets was subsequently evaluated by analyzing their prognostic role in specific cancer using Kaplan-Meier plotter (http://Kmplot.com/analysis/) and Gene Expression Profiling Interactive Analysis (GEPIA) (http://gepia.cancer-pku.cn/). To better assess and verify the binding ability of erianin with its potential targets, molecular flexible docking was performed using Discovery Studio (DS). The valuable targets obtained from the above analysis and verification were further mapped to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway using the Database for Annotation, Visualization and Integrated Discovery (DAVID) (http://david.abcc.ncifcrf.gov/) to explore the possible signaling pathways disturbed/regulated by erianin. Furthermore, the in silico prediction of absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of erianin was also performed and provided in this paper. Overall, in this study, we aimed at 1) collecting all experiment-based important information regarding the anticancer effect and pharmacological mechanism of erianin, 2) providing the predicted therapeutic targets and signaling pathways that erianin might act on in cancers, and 3) especially providing in silico ADMET properties of erianin.

Orchidaceae-Derived Anticancer Agents: A Review

Simple Summary

Orchids are commonly used in folk medicine for the treatment of infections and tumors but little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. According to the published data, numerous species of orchids contain potential antitumor chemicals. Still, a relatively insignificant number of species of orchids have been tested for their bioactive properties and most of those studies were on Asian taxa. Broader research, ’including American and African species, as well as the correct identification of samples, is essential for evaluating the usefulness of orchids as a plant family with huge anticancer potential.

Abstract

Species of orchids, which belong to the largest family of flowering plants, are commonly used in folk medicine for the treatment of infections and tumors. However, little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. For the assessment, previous papers on the anticancer activity of Orchidaceae published since 2015 were considered. The papers were found by exploring electronic databases. According to the available data, many species of orchids contain potential antitumor chemicals. The bioactive substances in a relatively insignificant number of orchids are identified, and most studies are on Asian taxa. Broader research on American and African species and the correct identification of samples included in the experiments are essential for evaluating the usefulness of orchids as a plant family with vast anticancer potential.

Erianin Controls Collagen-Mediated Retinal Angiogenesis via the RhoA/ROCK1 Signaling Pathway Induced by the alpha2/beta1 Integrin-Collagen Interaction

Purpose

Erianin has been reported to inhibit tumor activity by suppressing the expression of integrins. It is hypothesized that erianin can inhibit retinal neovascularization in collagen by suppressing the expression of integrins. With an aim to test this hypothesis, the regulation of erianin on collagen-mediated retinal angiogenesis via the Ras homolog gene family member A (RhoA)/Rho-associated coiled-coil containing protein kinase 1 (ROCK1) signaling pathway induced by α2 and β1 integrin-collagen interactions was investigated.

Methods

The effects of erianin on human retinal vascular endothelial cells (HRVECs) were assessed in vitro using a hypoxia model in a three-dimensional cell culture induced by cobalt (II) chloride (CoCl2). A hypoxia-induced retinopathy model in adult zebrafish and zebrafish embryos was established to assess the antiangiogenic effect of erianin with and without vitreous collagen in vivo. The expression of α2 and β1 integrin and RhoA/ROCK1 pathway in HRVECs and zebrafish retinas were analyzed.

Results

In vitro, collagen improved the angiogenic potential of HRVECs, including migration, adhesion, and tube formation, in a three-dimensional cell culture model. Erianin suppressed the angiogenic processes of the CoCl2-induced hypoxia HRVEC model in a concentration-dependent manner. In vivo, erianin reduced retinal angiogenesis in the hypoxia-induced retinopathy model in adult and embryo zebrafish. Erianin inhibited the expression of α2 and β1 integrin and RhoA/ROCK1 in a hypoxia-induced model in vitro in three-dimensional cell culture and in vivo in adult zebrafish.

Conclusions

Collagen-mediated retinal angiogenesis may be regulated by erianin via the RhoA/ROCK1 signaling pathway induced by α2 and β1 integrin-collagen interactions. These findings suggest that erianin has the therapeutic potential on intraocular collagen-mediated retinal angiogenesis.

Identification of Pyruvate Carboxylase as the Cellular Target of Natural Bibenzyls with Potent Anticancer Activity against Hepatocellular Carcinoma via Metabolic Reprogramming

Cancer cell proliferation in some organs often depends on conversion of pyruvate to oxaloacetate via pyruvate carboxylase (PC) for replenishing the tricarboxylic acid cycle to support biomass production. In this study, PC was identified as the cellular target of erianin using the photoaffinity labeling-click chemistry-based probe strategy. Erianin potently inhibited the enzymatic activity of PC, which mediated the anticancer effect of erianin in human hepatocellular carcinoma (HCC). Erianin modulated cancer-related gene expression and induced changes in metabolic intermediates. Moreover, erianin promotes mitochondrial oxidative stress and inhibits glycolysis, leading to insufficient energy required for cell proliferation. Analysis of 14 natural analogs of erianin showed that some compounds exhibited potent inhibitory effects on PC. These results suggest that PC is a cellular target of erianin and reveal the unrecognized function of PC in HCC tumorigenesis; erianin along with its analogs warrants further development as a novel therapeutic strategy for the treatment of HCC.

The Regulatory Effects and the Signaling Pathways of Natural Bioactive Compounds on Ferroptosis

Natural bioactive compounds abundantly presented in foods and medicinal plants have recently received a remarkable attention because of their various biological activities and minimal toxicity. In recent years, many natural compounds appear to offer significant effects in the regulation of ferroptosis. Ferroptosis is the forefront of international scientific research which has been exponential growth since the term was coined. This type of regulated cell death is driven by iron-dependent phospholipid peroxidation. Recent studies have shown that numerous organ injuries and pathophysiological processes of many diseases are driven by ferroptosis, such as cancer, arteriosclerosis, neurodegenerative disease, diabetes, ischemia-reperfusion injury and acute renal failure. It is reported that the initiation and inhibition of ferroptosis plays a pivotal role in lipid peroxidation, organ damage, neurodegeneration and cancer growth and progression. Recently, many natural phytochemicals extracted from edible plants have been demonstrated to be novel ferroptosis regulators and have the potential to treat ferroptosis-related diseases. This review provides an updated overview on the role of natural bioactive compounds and the potential signaling pathways in the regulation of ferroptosis.

The role of ferroptosis in lung cancer

Lung cancer is one of the most common cancers in the world. Although medical treatment has made impressive progress in recent years, it is still one of the leading causes of cancer-related deaths in men and women. Ferroptosis is a type of non-apoptotic cell death modality, usually characterized by iron-dependent lipid peroxidation, rather than caspase-induced protein cleavage. Excessive or lack of ferroptosis is associated with a variety of diseases, including cancer and ischaemia-reperfusion injury. Recent preclinical evidence suggests that targeting ferroptotic pathway is a potential strategy for the treatment of lung cancer. In this review, we summarize the core mechanism and regulatory network of ferroptosis in lung cancer cells, and highlight ferroptosis induction-related tumor therapies. The reviewed information may provide new insights for targeted lung cancer therapy.

Synthesis and Antiproliferative Evaluation of 3-Chloroazetidin-2-ones with Antimitotic Activity: Heterocyclic Bridged Analogues of Combretastatin A-4

Antimitotic drugs that target tubulin are among the most widely used chemotherapeutic agents; however, the development of multidrug resistance has limited their clinical activity. We report the synthesis and biological properties of a series of novel 3-chloro-β-lactams and 3,3-dichloro-β-lactams (2-azetidinones) that are structurally related to the tubulin polymerisation inhibitor and vascular targeting agent, Combretastatin A-4. These compounds were evaluated as potential tubulin polymerisation inhibitors and for their antiproliferative effects in breast cancer cells. A number of the compounds showed potent activity in MCF-7 breast cancer cells, e.g., compound 10n (3-chloro-4-(3-hydroxy-4-methoxy-phenyl)-1-(3,4,5-trimethoxyphenyl)azetidin-2-one) and compound 11n (3,3-dichloro-4-(3-hydroxy-4-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)-azetidin-2-one), with IC50 values of 17 and 31 nM, respectively, and displayed comparable cellular effects to those of Combretastatin A-4. Compound 10n demonstrated minimal cytotoxicity against non-tumorigenic HEK-293T cells and inhibited the in vitro polymerisation of tubulin with significant G2/M phase cell cycle arrest. Immunofluorescence staining of MCF-7 cells confirmed that β-lactam 10n caused a mitotic catastrophe by targeting tubulin. In addition, compound 10n promoted apoptosis by regulating the expression of pro-apoptotic protein BAX and anti-apoptotic proteins Bcl-2 and Mcl-1. Molecular docking was used to explore the potential molecular interactions between novel 3-chloro-β-lactams and the amino acid residues of the colchicine binding active site cavity of β-tubulin. Collectively, these results suggest that 3-chloro-2-azetidinones, such as compound 10n, could be promising lead compounds for further clinical anti-cancer drug development.

A Scientometric Visualization Analysis for Natural Products on Cancer Research from 2008 to 2020

Background: An increasing number of studies have shown that natural products have anti-tumor effects, and it has become a hotspot in cancer research. However, few bibliometric analyses have been examined in this field systematically. The current study aimed to explore the status and provide the developing trends in the natural products on cancer research.

Methods: Publications on natural products in cancer research were extracted from the Web of Science core collection database. CiteSpace (5.6.R3) software and GraphPad prism 6 were used to analyze and plot the references.

Results: On February 1, 2021, 34,611 records of natural products in cancer research published from 2008 to 2020 were collected. The United States was the driving force, with a strong academic reputation in this area. The top-contributing institution was the Chinese Academy of Sciences. Most publications were published in Molecules. Efferth Thomas was the most prolific author, while Newman DJ was the most cited and frequently co-cited author. Flavonoid, curcumin, and polyphenol were the most widely studied natural products. Oleanolic acid and rosmarinic acid have gradually become research hotspots recently. Breast cancer, prostate cancer, and colorectal cancer were the most common types of cancer in this field. “Natural killer cell” was the leading research hotspot. The keywords of “leaf extract,” “molecular docking” and “gold nanoparticle” appeared most recently as research frontiers.

Conclusion: Our results provided a general overview of the major research directions of natural products research in cancer. The mechanisms of natural products, especially those related to molecular docking, gold nanoparticle, gut microbiota, and immune checkpoints may soon become hotspots and should be closely monitored.

Erianin induces triple-negative breast cancer cells apoptosis by activating PI3K/Akt pathway

BACKGROUND

Triple-negative breast cancer (TNBC) is a refractory subtype of breast cancer, 25-30% of which have dysregulation in the PI3K/AKT pathway. The present study investigated the anticancer effect of erianin on TNBC cell line and its underlying mechanism.

METHODS

After treatment with erianin, MTT assay was employed to determine the MDA-MB-231 and EFM-192A cell proliferation, the nucleus morphological changes were observed by DAPI staining. The cell cycle and apoptotic proportion were detected by flow cytometry. Western blot was performed to determine the cell cycle and apoptosis-related protein expression and PI3K pathways. Finally, the antiproliferative activity of erianin was further confirmed by adding or not adding PI3K agonists SC79.

RESULTS

Erianin inhibited the proliferation of MDA-MB-231 and EFM-192A cells in a dose-dependent manner, the IC50 were 70.96 and 78.58 nM, respectively. Erianin could cause cell cycle arrest at the G2/M phase, and the expressions of p21 and p27 were up-regulated, while the expressions of CDK1 and Cyclin B1 were down-regulated. Erianin also induced apoptosis via the mitochondrial pathway, with the up-regulation of the expression of Cyto C, PARP, Bax, active form of Caspase-3, and Caspase-9. Furthermore, p-PI3K and p-Akt expression were down-regulated by erianin. After co-incubation with SC79, the cell inhibition rate of erianin was decreased, which further confirmed that the attenuated PI3K/Akt pathway was relevant to the pro-apoptotic effect of erianin.

CONCLUSIONS

Erianin can inhibit the proliferation of TNBC cells and induce cell cycle arrest and apoptosis, which may ascribe to the abolish the activation of the PI3K/Akt pathway.

Erianin regulates programmed cell death ligand 1 expression and enhances cytotoxic T lymphocyte activity

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium chrysotoxum Lindl is a cultivation of Dendrobium which belongs to the family of Orchidaceae. D. chrysotoxum Lindl is a traditional Chinese medicine with a wide range of clinical applications including tonic, astringent, analgesic and anti-inflammatory properties as early as the 28th century B.C. Erianin is a representative index component for the quality control of the D. chrysotoxum Lindl, which is included in the Pharmacopoeia of the People's Republic of China (2020 version).

AIM OF THE STUDY

To clarify the anti-tumour mechanisms of erianin in vitro and in vivo.

MATERIALS AND METHODS

We detected the anti-tumour activity of erianin using in vitro HeLa cell models and in vivo cervical cancer xenograft models. We performed MTT, western blot, RT-PCR, homology modeling, flow cytometry, and immunoprecipitation assays to study the proteins, genes, and pathways related to erianin's anti-tumour activity. LysoTracker Red staining was performed to detect lysosome function. Transwell, wound healing, tube formation, colony formation and EdU labelling assays were performed to determine cell proliferation, migration and invasion abilities, respectively. Cytotoxic T lymphocytes ability was confirmed using HeLa/T-cell co-culture model.

RESULTS

Experimental data demonstrated that erianin inhibited PD-L1 expression and induced the lysosomal degradation of PD-L1. Erianin suppressed HIF-1α synthesis through mTOR/p70S6K/4EBP1 pathway, and inhibited RAS/Raf/MEK/MAPK-ERK pathway. Immunoprecipitation experiments demonstrated that erianin reduced the interaction between RAS and HIF-1α. Experiments using a co-cultivation system of T cells and HeLa cells confirmed that erianin restored cytotoxic T lymphocytes ability to kill tumour cells. Erianin inhibited PD-L1-mediated angiogenesis, proliferation, invasion and migration. The anti-proliferative effects of erianin were supported using in vivo xenotransplantation experiments.

CONCLUSIONS

Collectively, these results revealed previously unknown properties of erianin and provided a new basis for improving the efficacy of immunotherapy against cervical cancer and other malignant tumours through PD-L1.

Recent research progress on natural small molecule bibenzyls and its derivatives in Dendrobium species

Orchidaceous plant Dendrobium genus is often used as a tonic, and its phenolic components have attracted attention for its anti-tumor and anti-diabetic complications. Bibenzyls is one of the essential phenolic active ingredients in the Dendrobium genus. At present, 89 bibenzyl derivatives have been extracted and identified from 46 Dendrobium species. The activity studies have shown that 42 compounds have pharmaceutical activity. Among them, 23 compounds showed antitumor activity; 7 compounds showed anti-diabetes and its complications activity; 10 compounds exhibited neuroprotective effects; 18 compounds showed antioxidant effects; 11 compounds had anti-inflammatory activity; 3 compounds had Antiplatelet aggregation effects; 3 compounds had antibacterial and antiviral effects. The Bibenzyls is small-molecular compounds of natural origin and widely sourced. Previous studies showed that the bibenzyls has good anti-tumor, anti-diabetes and its complications, and neuroprotective effects, and it has great potential for treating tumors, diabetes and its complications, Alzheimer's disease (AD) and Parkinson's disease (PD). Additionally, compounds such as moscatilin (1), gigantol (2) and chrysotoxine (3) have been further studied as lead compounds, and compounds exhibited therapeutical effects had been synthesized. Enough pieces of evidences have shown that the Bibenzyls have good development prospects. This article reviews the pharmacological effects of bibenzyls in Dendrobium species and provides an idea for its further development.

Erianin Induces Apoptosis and Autophagy in Oral Squamous Cell Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is a leading cause of cancer-related deaths worldwide. It has a very poor prognosis with over a 5-year survival rate of only 50%. Thus, it is important to identify effective therapeutic interventions against oral cancer. Apoptosis and autophagy have reported genetically regulated in physiology and diseases, which close relationship. Many natural compound study objects anticancer effect have been studied between apoptosis and autophagy relationship. The present study was designed to evaluate the effect of erianin on human oral cancer cell proliferation. Results of the study revealed that treatment with erianin significantly reduced the viability of different OSCC cell lines. Erianin exerted its cytotoxic effect by inducing cell cycle arrest and caspase-dependent apoptotic pathways. Both intrinsic and extrinsic pathways were found to be involved in erianin-mediated cell death. In addition, treatment with erianin also increased autophagy in OSCC cells. With further analysis, it was found that erianin induced both apoptosis and autophagy by regulating MAPK signaling pathways. Taken together, our study indicates that erianin plays an important role in reducing oral cancer cell viability, and thus, can be considered as a potential anticancer agent.