Dioscin inhibits colon cancer cells' growth by reactive oxygen species-mediated mitochondrial dysfunction and p38 and JNK pathways

Natural products targeting the MAPK-signaling pathway in cancer: overview

PURPOSE

This article summarizes natural products that target the MAPK-signaling pathway in cancer therapy. The classification, chemical structures, and anti-cancer mechanisms of these natural products are elucidated, and comprehensive information is provided on their potential use in cancer therapy.

METHODS

Using the PubMed database, we searched for keywords, including "tumor", "cancer", "natural product", "phytochemistry", "plant chemical components", and "MAPK-signaling pathway". We also screened for compounds with well-defined structures that targeting the MAPK-signaling pathway and have anti-cancer effects. We used Kingdraw software and Adobe Photoshop software to draw the chemical compound structural diagrams.

RESULTS

A total of 131 papers were searched, from which 85 compounds with well-defined structures were selected. These compounds have clear mechanisms for targeting cancer treatment and are mainly related to the MAPK-signaling pathway. Examples include eupatilin, carvacrol, oridonin, sophoridine, diosgenin, and juglone. These chemical components are classified as flavonoids, phenols, terpenoids, alkaloids, steroidal saponins, and quinones.

CONCLUSIONS

Certain MAPK pathway inhibitors have been used for clinical treatment. However, the clinical feedback has not been promising because of genomic instability, drug resistance, and side effects. Natural products have few side effects, good medicinal efficacy, a wide range of sources, individual heterogeneity of biological activity, and are capable of treating disease from multiple targets. These characteristics make natural products promising drugs for cancer treatment.

Dioscorea nipponica Makino: A comprehensive review of its chemical composition and pharmacology on chronic kidney disease

Chronic kidney disease (CKD) is a widespread ailment that significantly impacts global health. It is characterized by high prevalence, poor prognosis, and substantial healthcare costs, making it a major public health concern. The current clinical treatments for CKD are not entirely satisfactory, leading to a high demand for alternative therapeutic options. Chinese herbal medicine, with its long history, diverse varieties, and proven efficacy, offers a promising avenue for exploration. One such Chinese herbal medicine, Dioscorea nipponica Makino (DNM), is frequently used to treat kidney diseases. In this review, we have compiled studies examining the mechanisms of action of DNM in the context of CKD, focusing on five primary areas: improvement of oxidative stress, inhibition of renal fibrosis, regulation of metabolism, reduction of inflammatory response, and regulation of autophagy.

Natural products and mitochondrial allies in colorectal cancer therapy

Colorectal cancer (CRC) is a globally prevalent malignancy with a high potential for metastasis. Existing cancer treatments have limitations, including drug resistance and adverse effects. Researchers are striving to develop effective therapies to address these challenges. Impressively, contemporary research has discovered that many natural products derived from foods, plants, insects, and marine invertebrates can suppress the progression, metastasis, and invasion of CRC. In this review, we conducted a comprehensive search of the CNKI, PubMed, Embase, and Web of Science databases from inception to April 2023 to evaluate the efficacy of natural products targeting mitochondria to fight against CRC. Mitochondria are intracellular energy factories involved in cell differentiation, signal transduction, cell cycle regulation, apoptosis, and tumorigenesis. The identified natural products have been classified and summarized based on their mechanisms of action. These findings indicate that natural products can induce apoptosis in colorectal cancer cells by inhibiting the mitochondrial respiratory chain, ROS elevation, disruption of mitochondrial membrane potential, the release of pro-apoptotic factors, modulation of the Bcl-2 protein family to facilitate cytochrome c release, induction of apoptotic vesicle activity by activating the caspase protein family, and selective targeting of mitochondrial division. Furthermore, diverse apoptotic signaling pathways targeting mitochondria, such as the MAPK, p53, STAT3, JNK and AKT pathway, have been triggered by natural products. Natural products such as diosgenin, allopurinol, and clausenidin have demonstrated low toxicity, high efficacy, and multi-targeted properties. Mitochondria-targeting natural products have great potential for overcoming the challenges of CRC therapy.

The mechanism of dioscin preventing lung cancer based on network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Dioscorea nipponica Makino as a Chinese folk medicine has been used for the treatment of chronic bronchitis, cough, and asthma. Several studies have established the antimetastatic potential of Dioscorea nipponica Makino extract. Dioscin is a major bioactive compound in Dioscorea nipponica Makino and has anti-tumor property in lung cancer cell lines. However, the preventive effect of dioscin against lung cancer and its key mechanism haven't been identified yet.

AIM OF STUDY

To identify the prevention effect of dioscin on lung cancer and explore its key mechanism based on network pharmacology and experimental validation.

METHODS

The potential targets of dioscin were obtained from the HERB database. The therapeutic targets of lung cancer were acquired from the GeneCards database. Protein-protein interaction network (PPI) was constructed in the STRING 11.0 database. The David database was used for enrichment analysis. Molecular Docking was finished by the AutoDock Vina. NSCLC cell lines and mouse lung cancer model were used to confirm the prevention effect of dioscin on lung cancer and its key mechanism.

RESULTS

76 potential targets of dioscin were identified to be involved in lung cancer treatment, which refer to 512 biological processes, 47 molecular functions, 77 cellular components and 107 signal pathways. The molecular docking suggested that dioscin might bind to AKT1, Caspase3, TP53, C-JUN and IL-6. The DARTS indicated that dioscin could bind to AKT1. In vitro, dioscin could decrease proliferation, invasion and migration in A549 and PC-9 cells with the significant reduction in the expression of p-AKT, MMP2, and PCNA. In vivo, dioscin could reduce lung nodules, lung injury, and mortality in mouse lung cancer model with reducing the expression of p-AKT, MMP2, PCNA and increasing the expression of active-caspase3.

CONCLUSION

Dioscin could prevent lung cancer and its key target is AKT1 kinase, a center protein of PI3K/AKT signaling pathway.

Thiazolidinedione-Based Structure Modification of Celastrol Provides Thiazolidinedione-Conjugated Derivatives as Potent Agents against Non-Small-Cell Lung Cancer Cells through a Mitochondria-Mediated Apoptotic Pathway

In order to improve the potential of celastrol against non-small-cell lung cancer cells, the privileged structure, thiazolidinedione, was introduced into its C-20 carboxylic group with acetylpiperazine as a linker, and the thiazolidinedione-conjugated compounds 10a-10t were prepared. The target compounds were evaluated for their cytotoxic activities against the A549 cell line, and the results showed that most of the compounds 10a-10t displayed improved potency over celastrol, and compound 10b exhibited significant activity against the A549 cell line, with an IC₅₀ value of 0.08 μM, which was 13.8-fold more potent than celastrol (IC₅₀ = 1.10 μM). The mechanistic studies suggested that 10b could induce A549 cell apoptosis, as evidenced by Hoechst 33342 staining and annexin V-FITC/propidium iodide dual staining assays. Western blot analysis suggested that compound 10b could upregulate Bax expression, downregulate Bcl-2 expression, and activate the mitochondria-mediated apoptotic pathway. Furthermore, compound 10b could effectively inhibit tumor growth when tested in an A549 cell xenograft mouse model. Collectively, compound 10b is worthy of further investigation to support the discovery of effective agents against non-small-cell lung cancer.

Naturally occurring steroidal saponins as potential anticancer agents: Current developments and mechanisms of action

Cancer is claimed as a prevalent cause of mortality throughout the world. Conventional chemotherapy plays a pivotal role in the treatment of cancers, but the multidrug resistance has already become one of the major impediments for efficacious cancer therapy, creating a great demand for the development of novel anticancer drugs. Steroidal saponins, abundantly found in nature, possess extensive structural variability, and some naturally occurring steroidal saponins exhibited profound anticancer properties through a variety of pathways. Hence, naturally occurring steroidal saponins are powerful lead compounds/candidates in the development of novel therapeutic agents. This review article described the recent progress in naturally occurring steroidal saponins as potential anticancer agents, and the mechanisms of action were also discussed, covering articles published between 2017 and 2021.

Developments in the Antitumor Activity, Mechanisms of Action, Structural Modifications, and Structure-Activity Relationships of Steroidal Saponins

Steroidal saponins, a class of natural products formed by the combination of spirosteranes with sugars, are widely distributed in plants and have various biological activities, such as anti-tumor, anti-inflammatory, anti-bacterial, anti-Alzheimer's, anti-oxidation, etc. Particularly, extensive researches on the antitumor property of steroidal saponins have been received. Steroidal sapogenins, the aglycones of steroidal saponins, also have attracted much attention due to a vast range of pharmacological activities similar to steroidal saponins. In the past few years, structural modifications on the aglycones and sugar chains of steroidal saponins have been carried out and some achievements have been made. In this mini-review, the antitumor activity, action mechanisms, and structural modifications along with the structure-activity relationships of steroidal saponins and their derivatives are summarized.

Dioscin: A review on pharmacological properties and therapeutic values

Dioscin has gained immense popularity as a natural, bioactive steroid saponin, which offers numerous medical benefits. The growing global incidence of disease-associated morbidity and mortality continues to compromise human health, facilitating an increasingly urgent need for nontoxic, noninvasive, and efficient treatment alternatives. Natural compounds can contribute vastly to this field. Over recent years, studies have demonstrated the remarkable protective actions of dioscin against a variety of human malignancies, metabolic disorders, organ injuries, and viral/fungal infections. The successful usage of this phytocompound has been widely seen in medical treatment procedures under traditional Chinese medicine, and it is becoming progressively prevalent worldwide. This review provides an insight into the wide spectrum of pharmacological activities of dioscin, as reported and compiled in recent literature. The various novel approaches and applications of dioscin also verify the advantages exhibited by plant extracts against commercially available drugs, highlighting the potential of phytochemical agents like dioscin to be further incorporated into clinical practice.

The Crosstalk Between Signaling Pathways and Cancer Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. Metabolic reprogramming represents an important cancer hallmark in CRC. Reprogramming core metabolic pathways in cancer cells, such as glycolysis, glutaminolysis, oxidative phosphorylation, and lipid metabolism, is essential to increase energy production and biosynthesis of precursors required to support tumor initiation and progression. Accumulating evidence demonstrates that activation of oncogenes and loss of tumor suppressor genes regulate metabolic reprogramming through the downstream signaling pathways. Protein kinases, such as AKT and c-MYC, are the integral components that facilitate the crosstalk between signaling pathways and metabolic pathways in CRC. This review provides an insight into the crosstalk between signaling pathways and metabolic reprogramming in CRC. Targeting CRC metabolism could open a new avenue for developing CRC therapy by discovering metabolic inhibitors and repurposing protein kinase inhibitors/monoclonal antibodies.

Cancer Chemopreventive Role of Dietary Terpenoids by Modulating Keap1-Nrf2-ARE Signaling System—A Comprehensive Update

ROS, RNS, and carcinogenic metabolites generate excessive oxidative stress, which changes the basal cellular status and leads to epigenetic modification, genomic instability, and initiation of cancer. Epigenetic modification may inhibit tumor-suppressor genes and activate oncogenes, enabling cells to have cancer promoting properties. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that in humans is encoded by the NFE2L2 gene, and is activated in response to cellular stress. It can regulate redox homoeostasis by expressing several cytoprotective enzymes, including NADPH quinine oxidoreductase, heme oxygenase-1, UDP-glucuronosyltransferase, glutathione peroxidase, glutathione-S-transferase, etc. There is accumulating evidence supporting the idea that dietary nutraceuticals derived from commonly used fruits, vegetables, and spices have the ability to produce cancer chemopreventive activity by inducing Nrf2-mediated detoxifying enzymes. In this review, we discuss the importance of these nutraceuticals in cancer chemoprevention and summarize the role of dietary terpenoids in this respect. This approach was taken to accumulate the mechanistic function of these terpenoids to develop a comprehensive understanding of their direct and indirect roles in modulating the Keap1-Nrf2-ARE signaling system.

A Comprehensive Overview of Colon Cancer- A Grim Reaper of the 21st Century

A few decades ago, the incidence of colorectal cancer (CRC) was low and is now the fourth in the list of deadly cancers producing nearly a million deaths annually. A population that is aging along with risk factors such as smoking, obesity, sedentary lifestyle with little or no physical activity, and non-healthy food habits of developed countries can increase the risk of colorectal cancer. The balance in gut microbiota and the metabolites produced during bacterial fermentation within the host plays a significant role in regulating intestinal diseases as well as colorectal cancer development. Recent progress in the understanding of illness resulted in multiple treatment options such as surgery, radiation, and chemotherapy, including targeted therapy and multitherapies. The treatment plan for CRC depends on the location, stage and grade of cancer as well as genomic biomarker tests. Despite all the advancements made in the genetic and molecular aspects of the disease, the knowledge seems inadequate as the drug action as well as the wide variation in drug response did not appear strongly correlated with the individual molecular and genetic characteristics, which suggests the requirement of comprehensive molecular understanding of this complex heterogeneous disease. Furthermore, multitherapies or a broad spectrum approach, which is an amalgamation of the various promising as well as effective therapeutic strategies that can tackle heterogeneity and act on several targets of the disease, need to be validated in clinical studies. The latest treatment options have significantly increased the survival of up to three years in the case of advanced disease. The fact that colorectal cancer is developed from a polypoid precursor, as well as the symptoms of the disease that occur at an advanced stage, underlines how screening programs can help early detection and decrease mortality as well as morbidity from CRC.

Anti-obesity Medications in Cancer Therapy: A Comprehensive Insight

The interplay between cancer and obesity is multifactorial and complex with the increased risk of cancer development in obese individuals posing a significant threat. Obesity leads to the upregulation or hyperactivation of several oncogenic pathways in cancer cells, which drives them towards a deleterious phenotype. The cross-talk between cancer and obesity is considered a large contributing factor in the development of chemotherapeutic drug resistance and the resistance to radiotherapy. The link between obesity and the development of cancer is so strong that a medication that demonstrates effectiveness against both conditions would serve as an essential step. In this context, anti-obesity medications provide a worthy list of candidates based on their chemo-preventive potential and chemotherapeutic properties. The current study focuses on exploring the potential of anti-obesity medicines as dual anticancer drugs. These medications target several key signaling pathways (e.g., AMPK, PI3K/Akt/mTOR, MAPK, NF-κB, JNK/ERK), which prove to be crucial for both cancer growth and metastases. Some of these drugs also play an important role in attenuating the signaling and cellular events which incite cancer-obesity cross-talk and demonstrate efficient counteraction of neoplastic transformation. Thus, this review highlights a comprehensive view of the potential use of anti-obesity medicines to treat both cancer and obesity for patients exhibiting both comorbities.

The Role of Reactive Oxygen Species in Tumor Treatment and its Impact on Bone Marrow Hematopoiesis

Reactive oxygen species (ROS), an important molecule inducing oxidative stress in organisms, play a key role in tumorigenesis, tumor progression and recurrence. Recent findings on ROS have shown that ROS can be used to treat cancer as they accelerate the death of tumor cells. At present, pro-oxidant drugs that are intended to increase ROS levels of the tumor cells have been widely used in the clinic. However, ROS are a double-edged sword in the treatment of tumors. High levels of ROS induce not only the death of tumor cells but also oxidative damage to normal cells, especially bone marrow hemopoietic cells, which leads to bone marrow suppression and (or) other side effects, weak efficacy of tumor treatment and even threatening patients' life. How to enhance the killing effect of ROS on tumor cells while avoiding oxidative damage to the normal cells has become an urgent issue. This study is a review of the latest progress in the role of ROS-mediated programmed death in tumor treatment and prevention and treatment of oxidative damage in bone marrow induced by ROS.

Dioscin inhibits human endometrial carcinoma proliferation via G0/G1 cell cycle arrest and mitochondrial-dependent signaling pathway

The present study emphasized on the anti-cancerous effects of dioscin and its underlying molecular mechanism in human endometrial cancer Ishikawa cells. Dioscin significantly suppressed the proliferation of Ishikawa cells at IC₅₀ of 2.37 μM. Besides, dioscin could inhibit the proliferation of Ishikawa cells by blocking the G0/G1 cell cycle through up-regulation of p16, p21, and p27 and down-regulation of cycle-cellular protein (Cyclin A/D/E) and cyclin-dependent kinase (CDK2/4/6). Also, it promoted apoptosis through the mitochondrial pathway, including the regulation of Bcl family proteins, the increase of ROS levels, the activation of caspases (Caspase 9/3), and the decrease of mitochondrial membrane permeability. Whereas dioscin also effectively activated the marker genes and proteins (Fas, TNF-R1, and Caspase 8) related to the death receptor-mediated pathway which confirmed the involvement of both the pathways for dioscin-induced apoptosis. The current results demonstrated that dioscin possessed potential health benefits with respect to endometrial cancer prevention and treatment.

Inhibition of invadopodia formation by diosgenin in tumor cells

Diosgenin is a type of steroid extracted from the rhizome of Dioscorea plants. In traditional Chinese medicine, Dioscorea has the effect of ‘eliminating phlegm, promoting digestion, relaxing tendons, promoting blood circulation and inhibiting malaria’. Recent studies have confirmed that diosgenin exhibits a number of pharmacological effects, including antitumor activities. Through its antitumor effect, diosgenin is able to block tumor progression and increase the survival rate of patients with cancer; ultimately improving their quality of life. However, the mechanism underlying its pharmacological action remains unclear. Once tumor cells reach a metastatic phase, it can be fatal. Increased migration and invasiveness are the hallmarks of metastatic tumor cells. Invadopodia formation is key to maintaining the high migration and invasive ability of tumor cells. Invadopodia are a type of membrane structure process rich in filamentous-actin and are common in highly invasive tumor cells. In addition to actin, numerous actin regulators, including cortical actin-binding protein (Cortactin), accumulate in invadopodia. Cortactin is a microfilament actin-binding protein with special repetitive domains that are directly involved in the formation of the cortical microfilament actin cell skeleton. Cortactin is also one of the main substrates of intracellular Src-type tyrosine protein kinases and represents a highly conserved family of intracellular cortical signaling proteins. In recent years, great progress has been made in understanding the role of Cortactin and its molecular mechanism in cell motility. However, the diosgenin-Cortactin-invadopodia mechanism is still under investigation. Therefore, the present review focused on the current research on the regulation of invadopodia by diosgenin via Cortactin.

Dioscin facilitates ROS-induced apoptosis via the p38-MAPK/HSP27-mediated pathways in lung squamous cell carcinoma

Lung squamous cell carcinoma (SCC) is one of the deadliest cancers both in China and worldwide. To date, the efficacy of lung SCC treatments is limited. Recent studies have elucidated the powerful anti-tumour role of dioscin in different human cancers. Here, our study aims to investigate the effect of dioscin on lung SCC and its underlying mechanism. First, we found that dioscin not only inhibited cell proliferation and cell migration and induced cell apoptosis in lung SCC cells but also suppressed tumour growth in tumour-bearing mice. Furthermore, we noted that the accumulation of intracellular reactive oxygen species (ROS) was triggered by dioscin in lung SCC cells, leading to the phosphorylation of HSP27 through p38-MAPK and consequent cell apoptosis. The activation of p38-MAPK/HSP27 induced by the p38-MAPK activator Anisomycin enhanced the apoptosis of lung SCC cells, while the ROS inhibitor N-acetyl-L-cysteine (NAC) and the p38-MAPK inhibitor SB203580 both attenuated dioscin-mediated cell apoptosis. Moreover, NAC suppressed the activation of p38-MAPK/HSP27 that induced by dioscin. In conclusion, these results confirm that dioscin facilitates ROS-induced apoptosis via the p38-MAPK/HSP27-mediated pathway in lung SCC.

Propranolol induced apoptosis and autophagy via the ROS/JNK signaling pathway in Human Ovarian Cancer

Propranolol has a significant anti-cancer effect towards various cancers. Our study aimed at investigating the underlying mechanism of Propranolol's therapeutic effect towards ovarian cancer. Specifically, Propranolol significantly reduced the viability of human ovarian cancer cell lines SKOV-3 and A2780 in a dose- and time-dependent manner. Flow cytometry analysis revealed that Propranolol induced the cell cycle arrest at G2/M phase therefore leading to apoptosis. Moreover, autophagy inhibitor 3-MA markedly enhanced the Propranolol-induced apoptosis. In addition, reactive oxygen species (ROS) increased dramatically after Propranolol treatment and Propranolol activated the phosphorylation of JNK. What is more, p38 inhibitor SB203580 and JNK inhibitor SP600125 attenuated the upregulated expression of LC3-II and cleaved-caspase-3 by the effect of Propranolol. ROS exclusive inhibitor antioxidant N-acetyl cysteine (NAC) weakens the phosphorylation of JNK proteins induced by Propranolol. In summary, these results suggested that Propranolol induced cell apoptosis and protective autophagy through the ROS/JNK signaling pathway in human ovarian cancer cells.

Diosgenin, a steroidal saponin, and its analogs: Effective therapies against different chronic diseases

BACKGROUND

Chronic diseases are a major cause of mortality worldwide, and despite the recent development in treatment modalities, synthetic drugs have continued to show toxic side effects and development of chemoresistance, thereby limiting their application. The use of phytochemicals has gained attention as they show minimal side effects. Diosgenin is one such phytochemical which has gained importance for its efficacy against the life-threatening diseases, such as cardiovascular diseases, cancer, nervous system disorders, asthma, arthritis, diabetes, and many more.

AIM

To evaluate the literature available on the potential of diosgenin and its analogs in modulating different molecular targets leading to the prevention and treatment of chronic diseases.

METHOD

A detailed literature search has been carried out on PubMed for gathering information related to the sources, biosynthesis, physicochemical properties, biological activities, pharmacokinetics, bioavailability and toxicity of diosgenin and its analogs.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and clinical trials that reported the efficacy of diosgenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK, etc., which play a crucial role in the development of most of the diseases. Reports have also revealed the safety of the compound and the adaptation of nanotechnological approaches for enhancing its bioavailability and pharmacokinetic properties.

SIGNIFICANCE

Thus, the review summarizes the efficacy of diosgenin and its analogs for developing as a potent drug against several chronic diseases.

α‑Solanine inhibits growth and metastatic potential of human colorectal cancer cells

Solanum nigrum L. (Longkui) is one the most widely used anticancer herbs in traditional Chinese medicine. α‑Solanine is an important ingredient of S. nigrum L. and has demonstrated anticancer properties in various types of cancer. However, the effects of α‑solanine on colorectal cancer remain elusive. The aim of the present study was to assess the effects of α‑solanine on human colorectal cancer cells. The results demonstrated that α‑solanine inhibited the proliferation of RKO cells in a dose‑ and time‑dependent manner. In addition, α‑solanine arrested the cell cycle at the G0/G1 phase and suppressed the expression levels of cyclin D1 and cyclin‑dependent kinase 2 in RKO cells. α‑Solanine induced apoptosis of RKO cells, as indicated by morphological changes and positive Annexin‑FITC/propidium iodide staining. Additionally, α‑solanine activated caspase‑3, ‑8 and ‑9 in RKO cells, which contributed to α‑solanine‑induced apoptosis. α‑Solanine also increased the generation of reactive oxygen species, which contributed to caspase activation and induction of apoptosis. α‑Solanine inhibited the migration, invasion and adhesion of RKO cells, as well as the expression levels and activity of matrix metalloproteinase (MMP)‑2 and MMP‑9. In addition, α‑solanine inhibited cell proliferation, activated caspase‑3, ‑8 and ‑9, induced apoptosis, and inhibited the migration and invasion of HCT‑116 cells. Furthermore, α‑solanine inhibited tumor growth and induced apoptosis in vivo. These findings demonstrated that α‑solanine effectively suppressed the growth and metastatic potential of human colorectal cancer.

Dioscin Inhibited Glycolysis and Induced Cell Apoptosis in Colorectal Cancer via Promoting c-myc Ubiquitination and Subsequent Hexokinase-2 Suppression

Purpose

Dioscin is a natural product isolated from traditional Chinese medicines and is reported to have antitumor activities against several cancers. In the present study, we aimed to investigate its potency against colorectal cancers, especially the effects on tumor glycolysis, and to elaborate related molecular mechanisms.

Methods

The antitumor activities of dioscin were evaluated by cell proliferation assays and colony formation assays in vitro and the mouse xenograft models in vivo. The effects of dioscin on tumor glycolysis were determined by measuring glucose absorption and lactate generation. Cell apoptosis was detected by cleaved PARP and the activity of caspase-3. Protein overexpression or gene knockdown was conducted to illustrate molecular mechanisms. Immunoprecipitation experiments were applied to identify the interaction between different proteins.

Results

Dioscin substantially inhibited colorectal cancer cell proliferation in vitro and suppressed the xenograft growth in nude mice. After dioscin treatment, with the suppression of hexokinase-2, the tumor glycolysis was significantly decreased. Dioscin substantially impaired the interaction between hexokinase-2 and VDAC-1, and induced cell apoptosis. Exogenous overexpression of hexokinase-2 significantly antagonized the glycolysis suppression and apoptosis induction by dioscin. Through enhancing the binding of E3 ligase FBW7 to c-myc, dioscin promoted the ubiquitination of c-myc and gave rise to c-myc degradation, which contributed to the inhibition of hexokinase-2.

Conclusion

Our studies revealed a novel mechanism by which dioscin exerted its antitumor activity in colorectal cancer, and verified that dioscin or its analog might have potentials for colorectal cancer therapy.

Cdh1-mediated Skp2 degradation by dioscin reprogrammes aerobic glycolysis and inhibits colorectal cancer cells growth

BACKGROUND

The F-box protein S-phase kinase-associated protein 2 (Skp2) is overexpressed and correlated with poor prognosis in human malignancies, including colorectal cancer (CRC).

METHODS

A natural product library was used for natural compound screening through glycolysis analysis. The expression of Skp2 in CRCs and the inhibitory effect of dioscin on glycolysis were examined through methods of immunoblot, immunofluorescence, immunohistochemical staining, anchorage-dependent and -independent growth assays, EdU incorporation assay, ubiquitination analysis, co-immunoprecipitation assay, CRISPR-Cas9-based gene knockout, and xenograft experiment.

FINDINGS

We demonstrated that Skp2 was highly expressed in CRC tissues and cell lines. Knockout of Skp2 inhibited HK2 and glycolysis and decreased CRC cell growth in vitro and in vivo. We screened 88 commercially available natural products and found that dioscin, a natural steroid saponin derived from several plants, significantly inhibited glycolysis in CRC cells. Dioscin decreased the protein level of Skp2 by shortening the half-life of Skp2. Further study showed that dioscin attenuated Skp2 phosphorylation on S72 and promoted the interaction between Skp2 and Cdh1, which eventually enhanced Skp2 lysine 48 (K48)-linked polyubiquitination and degradation. Depletion of Cdh1 impaired dioscin-induced Skp2 reduction, rescued HK2 expression, and glycolysis in CRC cells. Finally, dioscin delayed the in vivo tumor growth, promoted Skp2 ubiquitination, and inhibited Skp2 expression in a mouse xenograft model.

INTERPRETATION

This study suggests that in addition to pharmacological inactivation of Skp2, enhancement of ubiquitination-dependent Skp2 turnover is a promising approach for cancer treatment.

Dioscin attenuates oxLDL uptake and the inflammatory reaction of dendritic cells under high glucose conditions by blocking p38 MAPK

Dioscin has been shown to affect the regulation of metabolic diseases, including diabetes; however, the mechanism of action is still unclear. Under high glucose (HG) conditions, the expression of scavenger receptors and the uptake of oxidized low‑density lipoprotein (oxLDL) are upregulated in dendritic cells (DCs), which are critical steps in atherogenesis and inflammation. In this study, the focus was on the impact of dioscin on the function of DCs. Immature DCs were cultured with: 5.5 mM glucose medium (control group); 30 mM glucose medium (HG group); HG + 10 mM dioscin; HG + 20 mM dioscin; HG + 30 mM dioscin; and HG + 40 mM dioscin. For subsequent experiments, 30 mM dioscin was used as the experimental concentration. Dichlorodihydrofluorescein fluorescence was used to measure the intracellular production of reactive oxygen species (ROS) in DCs. The expression levels of the scavenger receptors, including class A scavenger receptors (SR‑A), CD36 and lectin‑like oxidized low‑density lipoprotein receptor‑1 (LOX‑1) were determined via quantitative PCR. The protein expression of p38 mitogen‑activated protein kinase (MAPK) was determined by western blotting. Furthermore, ELISA was used to detect the levels of interleukin (IL)‑6, IL‑10 and IL‑12. Finally, DCs were incubated with diOlistic (Dil)‑labeled oxLDL, and flow cytometry analysis was used to investigate the Dil‑oxLDL‑incorporated fraction. The incubation of DCs with dioscin inhibited the induction of ROS production, in a dose‑dependent manner, under HG conditions. The upregulation of SR‑A, CD36 and LOX‑1 genes was partially abolished by dioscin, which also partially reversed p38 MAPK protein upregulation. Furthermore, increased secretion of IL‑6 and IL‑12, and decreased secretion of IL‑10 in DCs, induced by HG, was also reversed by dioscin. To conclude, dioscin could attenuate the production of ROS, inflammatory cytokine secretion and oxLDL uptake by DCs in HG conditions by preventing the expression of scavenger receptors and p38 MAPK, thus playing a positive role in preventing atherogenesis.

Development of an Oriental Medicine Discrimination Method through Analysis of Steroidal Saponins in Dioscorea nipponica Makino and Their Anti-Osteosarcoma Effects

To prevent confusing Dioscorea nipponica (DN), an Oriental medicine, with Dioscorea quinquelobata (DQ) and Dioscorea septemloba (DS), a simple and accurate quantitative analysis method using HPLC combined with ultraviolet (UV) detection was developed and verified with UPLC-QTOF/MS through identification of five saponin glycosides: protodioscin (1), protogracillin (2), pseudoprotodioscin (3), dioscin (4), and gracillin (5). The newly developed analysis method showed sufficient reproducibility (<1.91%) and accuracy (92.1%–102.6%) and was able to identify DN based on the presence of compound 3 (13.821 ± 0.037 mg/mL) and the absence of 5. Compound 1, which is present in DN at a relatively high level (159.983 ± 0.064 mg/mL), was also an important marker for identification. Among the three species, DN showed the strongest activation of apoptotic signaling in osteosarcoma cells, while the four compounds detected in DN showed IC₅₀ values of 6.43 (1), 10.61 (2), 10.48 (3), and 6.90 (4). In conclusion, the strong inhibitory effect of DN against osteosarcoma was confirmed to be associated with 1 and 4, which is also related to the quantitative results. Therefore, the results of this study might provide important information for quality control related to Oriental medicine.

Dioscin inhibits the growth of human osteosarcoma by inducing G2/M-phase arrest, apoptosis, and GSDME-dependent cell death in vitro and in vivo

Pyroptosis is a form of programmed cell death (PCD) that plays a vital role in immunity and diseases. Although it was recently reported that chemotherapy drugs can induce pyroptosis through caspase-3-dependent cleavage of gasdermin E (GSDME), the role of pyroptosis in osteosarcoma (OS) with dioscin is less understood. In this study, we explored the effects of dioscin on OS in vitro and in vivo and further elucidated the underlying molecular mechanisms and found that dioscin-triggered pyroptosis in GSDME-dependent cell death and that GSDME-N was generated by caspase-3. Furthermore, dioscin inhibited cancer cell growth by inducing G2/M arrest and apoptosis through the JNK/p38 pathway. In vivo, dioscin significantly inhibited OS proliferation. Taken together, our results demonstrate that dioscin can induce apoptosis through the JNK/p38 pathway and GSDME-dependent pyroptosis in OS, identifying it as a potential therapeutic drug for treatment of this disease.

Hepatocellular Toxicity of Paris Saponins I, II, VI and VII on Two Kinds of Hepatocytes-HL-7702 and HepaRG Cells, and the Underlying Mechanisms

Rhizoma paridis is a popularly-used Chinese medicine in clinics, based on the pharmacodynamic properties of its saponin components. The four main saponins in Rhizoma paridis are designated saponins I, II, VI, and VII. At present, much attention is focused on the anticancer effect of Rhizoma paridis which is manifested in its cytotoxicity to various cancer cells. The purpose of this study was to investigate the hepatocellular toxicities of the four saponins in Rhizoma paridis and the relative intensities of their cytotoxic effects. It was found that the four saponins were cytotoxic to two types of hepatocytes-HL-7702 and HepaRG cells. The cytotoxicities of the four saponins to the two cell models were compared. One of the most cytotoxic saponins was Rhizoma paridis saponin I (PSI). This was used to determine the mechanism of hepatocellular toxicity. Results from MTT assays demonstrated that the four saponins induced apoptosis of the two hepatocyte models in a dose-dependent and time-dependent manner. In addition, fluorescent 4′,6-diamidino-2-phenylindole (DAPI) staining was used to observe the morphological changes of HepaRG cells after saponin administration. Further, as the concentration increased, PSI-induced lactate dehydrogenase (LDH) release from HepaRG cells increased gradually. In addition, PSI enhanced the levels of reactive oxygen species (ROS) and blocked the S and G2 phases of the cell cycle in HepaRG cells. A western blot indicated that PSI upregulated the protein expression levels of p53, p21, and Fas. Furthermore, the PSI-induced changes in the p53 protein increased the Bax/bcl-2 ratio, resulting in enhancement of the release of mitochondrial cytochrome c, activation of caspases-3, -8, and -9, poly-ADP ribose polymerase (PARP), and ultimately apoptosis. Increased Fas protein activated caspase-8, which led to the activation of caspase-3 and its downstream PARP protein, resulting in cell apoptosis. These results indicate that PSI induced apoptosis in HepaRG cells through activation of ROS and death receptor pathways. The results obtained in this study suggest that the hepatocellular toxicity of saponins in Rhizoma paridis should be considered during the clinical application of this drug. In addition, they provide a reference for future anti-cancer studies on Rhizoma paridis.

Traditional Chinese medicine as a cancer treatment: Modern perspectives of ancient but advanced science

Traditional Chinese medicine (TCM) has been practiced for thousands of years and at the present time is widely accepted as an alternative treatment for cancer. In this review, we sought to summarize the molecular and cellular mechanisms underlying the chemopreventive and therapeutic activity of TCM, especially that of the Chinese herbal medicine-derived phytochemicals curcumin, resveratrol, and berberine. Numerous genes have been reported to be involved when using TCM treatments and so we have selectively highlighted the role of a number of oncogene and tumor suppressor genes in TCM therapy. In addition, the impact of TCM treatment on DNA methylation, histone modification, and the regulation of noncoding RNAs is discussed. Furthermore, we have highlighted studies of TCM therapy that modulate the tumor microenvironment and eliminate cancer stem cells. The information compiled in this review will serve as a solid foundation to formulate hypotheses for future studies on TCM-based cancer therapy.

Timosaponin AIII inhibits metastasis of renal carcinoma cells through suppressing cathepsin C expression by AKT/miR-129-5p axis

Timosaponin AIII (TSAIII) is a steroidal saponin that exerts anticancer activity on various cancer cells. In this study, we explore the effects of TSAIII on renal cell carcinoma (RCC) cells. Our findings show that TSAIII treatment (<8 μM) insignificantly influenced cell viability and cell cycle distribution of human RCC cell lines 786-O, A-498, and ACHN. Further observations revealed that TSAIII inhibited migration and invasion of 786-O and A-498 cells, as well as significantly decreased the production and expression of cathepsin C (CTSC) in both the cell types. Kinase cascade analysis exhibited that PI3K/AKT activation was inhibited, but PTEN expression was increased, in response to TSAIII treatments. Combining TSAIII and PI3K inhibitors, LY294002 synergically reduced the migration and invasion of 786-O and A-498 cells, as well as decreased the CTSC expression in both the cell types. We also observed that miR-129-5p bound to CTSC gene and suppressed the expression of CTSC and demonstrated that the miR-129-5p expression was synergically enhanced by TSAIII and LY294002. In addition, pretreatment with antago-miR-129-5p significantly restored the CTSC expression and the migration and invasion of TSAIII-treated 786-O cells. In conclusion, our findings reveal that TSAIII inhibits the metastatic properties of RCC cells, contributing to the inhibition of PI3K/AKT and the increase of miR-129-5p and the subsequent downregulation of CTSC. This suggests that TSAIII has significant antimetastatic activity against RCC cells and may be beneficial to RCC treatments.

Dioscin Inhibits Virulence Factors of Candida albicans

Candida albicans infections present a heavy burden upon public health, with only a few drugs available, while biofilms formed by C. albicans worsen this situation. Dioscin has antitumor, anti-inflammatory, and hepatoprotective effects, and this study was conducted to evaluate the effects of dioscin on the biofilm formation and development, as well as other virulence factors of C. albicans such as morphological transition, adhesion, and extracellular secreted phospholipase. Our results showed dioscin inhibits these virulence factors and has low cytotoxicity against mammalian cells. Considering protective effects of dioscin against damage on liver and kidney, dioscin may be used as a potential candidate for antifungal development.

Chemopreventive effects of some popular phytochemicals on human colon cancer: a review

The present review summarizes (1) the epidemiology and etiology of colon cancer, (2) generalized cancer chemoprotective mechanisms, and (3) the chemopreventive properties of some popular phytochemicals as well as some phytochemicals developed by our research group recently.