Wogonin induces apoptosis by activation of ERK and p38 MAPKs signaling pathways and generation of reactive oxygen species in human breast cancer cells

Wogonin induces apoptosis in macrophages by exhibiting cytotoxic and genotoxic effects

Macrophages play an important role in defending the body against invading pathogens. In the face of pathogens, macrophages become activated and release toxic materials that disrupt the pathogens. Macrophage overactivation can lead to severe illness and inflammation. Wogonin has several therapeutic effects, including anti-inflammatory, anticancer, antioxidant, and neuroprotective effects. No studies have investigated the cytotoxic effects of wogonin at concentrations of more than 0.1 mM in RAW264.7 cells. In this study, RAW 264.7 cells were treated with wogonin, which, at concentrations of more than 0.1 mM, had cytotoxic and genotoxic effects in the RAW264.7 cells, leading to apoptosis and necrosis. Further, wogonin at concentrations of more than 0.1 mM induced caspase-3, caspase-8, and caspase-9 activation and mitochondrial dysfunction and death receptor expression. These results suggest that wogonin induces apoptosis through upstream intrinsic and extrinsic pathways by exhibiting cytotoxic and genotoxic effects.

Wogonin, as a potent anticancer compound: From chemistry to cellular interactions

Chinese native medicine Scutellaria baicalensis Georgi, also referred to as Chinese skullcap or Huang-Qin, is frequently used to treat cancer, viral infections, and seizures. This plant's abundance of flavones (wogonoside) and their related aglycones (wogonin) is responsible for many of its pharmacologic effects. A significant ingredient in S. baicalensis that has been the subject of the most research is wogonin. Numerous preclinical investigations revealed that wogonin suppresses tumor growth by cell cycle arrest, stimulating cell death and preventing metastasis. This review focuses on a complete overview of published reports that suggest chemopreventive action of wogonin and the mechanistic insights behind these neoplastic activities. It also emphasizes the synergistic improvements made by wogonin in chemoprevention. The factual data in this mini-review stimulate additional research on chemistry and toxicological profile of wogonin to confirm its safety issues. This review will encourage researchers to generalize the merits of wogonin to be used as potential compound for cancer treatment.

Potential Therapeutic Mechanism of Scutellaria baicalensis Georgi against Ankylosing Spondylitis Based on a Comprehensive Pharmacological Model

Background

Scutellaria baicalensis Georgi (SBG) has significant anti-inflammatory and immune-modulating activities and is widely used in the treatment of inflammatory and autoimmune diseases. However, the mechanism of SBG in the treatment of ankylosing spondylitis (AS) remains to be elucidated.

Methods

Differentially expressed genes (DEGs) related to AS were analyzed based on two GEO gene chips. The DEGs were merged with the data derived from OMIM, GeneCards, and PharmGKB databases to ascertain AS-related targets. Active components of SBG and their targets were acquired from the TCMSP database. After overlapping the targets of AS and SBG, the action targets were acquired. Subsequently, protein-protein interaction (PPI) network and core target screening were conducted using the STRING database and Cytoscape software. Moreover, the DAVID platform was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of action targets. Finally, the affinity of major active components and core targets was validated with molecular docking.

Results

A total of 36 active components of SBG were acquired from TCMSP database. Among these, the main active components were baicalein, wogonin, and oroxylin A. The PPI network and screening showed TNF, IL-6, CXCL8, PTGS2, and VEGFA as core targets associated SBG against AS. GO and KEGG analyses indicated that SBG participated in various biological processes, via regulating IL-17, TNF, and NF-κB signaling pathways. Molecular docking results confirmed a strong binding activity between the main active components and the core targets.

Conclusion

The therapeutic mechanism of SBG associated with AS can be characterized as a multicomponent, multitarget, and multipathway mechanism. SBG may be a promising therapeutic candidate for AS.

Investigation of the mechanism of action of Shengxuexiaoban Capsules against primary immune thrombocytopenia using network pharmacology and experimental validation

BACKGROUND

Shengxuexiaoban Capsules (SC) is a classical prescription in traditional Chinese medicine (TCM) and has been clinically adopted in the treatment of primary immune thrombocytopenia (ITP) in China. However, the underlying mechanisms of the actions of SC on ITP remain clear.

METHODS

A network pharmacology approach was adopted to investigate the underlying molecular mechanism of SC in treating ITP, and the effects of SC on the proliferation, differentiation, and apoptosis of megakaryocyte (MK) and on the ITP animal model were investigated.

RESULTS

Network pharmacology analysis found 128 active compounds and 268 targets of these compounds in SC, as well as 221 ITP-related targets. The topological analysis found a central network containing 82 genes, which were significantly associated with the regulation of transcription, cell proliferation, apoptosis processes, the PI3K-AKT signaling pathway, the MAPK signaling pathway, and the ERK1 and ERK2 cascades. It showed that SC increased the proliferation and differentiation of MK, but had no significant impact on MK apoptosis in vivo. The addition of SC increased the gene expression of several potential targets, including STAT3, KDR, CASP3, and TGFB1. In addition, SC administration elevated the protein expression of p-AKT and inhibit the protein expression of p-ERK, but has no impact on the protein expression of p-P38. Moreover, SC could improve haemogram parameters, coagulation indicators, and the proliferation and differentiation of MK in the ITP animal model.

CONCLUSIONS

The present study systematically elucidated the underlying mechanisms of SC against ITP and provided an efficient strategy to discover the pharmacological mechanism of TCM. It may strengthen the understanding of SC and facilitate more application of this formula in the treatment of ITP.

Role of Plant-Derived Active Constituents in Cancer Treatment and Their Mechanisms of Action

Despite significant technological advancements in conventional therapies, cancer remains one of the main causes of death worldwide. Although substantial progress has been made in the control and treatment of cancer, several limitations still exist, and there is scope for further advancements. Several adverse effects are associated with modern chemotherapy that hinder cancer treatment and lead to other critical disorders. Since ancient times, plant-based medicines have been employed in clinical practice and have yielded good results with few side effects. The modern research system and advanced screening techniques for plants’ bioactive constituents have enabled phytochemical discovery for the prevention and treatment of challenging diseases such as cancer. Phytochemicals such as vincristine, vinblastine, paclitaxel, curcumin, colchicine, and lycopene have shown promising anticancer effects. Discovery of more plant-derived bioactive compounds should be encouraged via the exploitation of advanced and innovative research techniques, to prevent and treat advanced-stage cancers without causing significant adverse effects. This review highlights numerous plant-derived bioactive molecules that have shown potential as anticancer agents and their probable mechanisms of action and provides an overview of in vitro, in vivo and clinical trial studies on anticancer phytochemicals.

Antiproliferative Wnt inhibitor wogonin prevents eryptosis following ionophoric challenge, hyperosmotic shock, oxidative stress, and metabolic deprivation

Anemia is a common complication of chemotherapy and may arise due to premature or suicidal death of red blood cells (RBCs). Prevention of RBC death thus lends itself as a promising strategy to counteract anemia. Wogonin (WGN; 5,7-dihydroxy-8-methoxyflavone) is a Wnt inhibitor derived from Scutellaria baicalensis plant with potent cytotoxic and antitumor potential. However, the nature of interaction of WGN with human RBCs is unknown. RBCs from healthy participants were exposed to different hemolytic and eryptotic stimuli for 24 or 48 hr at 37°C in the presence and absence of 100 μM WGN. Calcium overload was induced by 2 μM ionomycin, hyperosmotic shock with excessive sucrose, oxidative stress by 2-phenethyl isothiocyanate (PEITC), and metabolic deprivation by exclusion of glucose. Hemolysis was estimated from extracellular hemoglobin, phosphatidylserine (PS) exposure by Annexin V-FITC, intracellular calcium by Fluo4/AM, and oxidative stress by 2',7'-dichlorodihydrofluorescein diacetate (H₂ DCFDA). While WGN did not rescue the cells from the hemolytic activity of ionomycin, it reduced PS externalization by interfering with calcium influx under both ionomycin treatment and metabolic exhaustion. WGN also significantly inhibited PS exposure upon hyperosmotic shock, but the effect was independent of calcium entry. Moreover, WGN exhibited antihemolytic and anti-eryptotic activities against PEITC without appreciable reduction in ROS levels. Altogether, WGN prevents PEITC-induced hemolysis and suppresses eryptosis due to calcium accumulation, hyperosmotic shock, oxidative stress, and metabolic exhaustion. These novel insights may open new avenues into the therapeutic application of WGN for conditions in which anemia is commonly encountered, most notably cancer. PRACTICAL APPLICATIONS: The herbal supplement Sho-Saiko-To (Xiaochaihu-tang) is commonly prescribed to relieve symptoms of liver disease. Flavonoids from the herbal constituents of Sho-Saiko-To have demonstrated considerable anti-inflammatory, antioxidant, antimicrobial, antitumor, and immunomodulatory properties. In this work, we identify WGN, a major flavonoid in Sho-Saiko-To, as a novel inhibitor of hemolysis and eryptosis of human erythrocytes. Since inordinate erythrocyte death is a major obstacle in therapeutic drug development, our findings argue for the use of WGN as a natural alternative, either as a primary or an adjuvant drug, for a wide assortment of pathological conditions including cancer.

Colorectal Adenocarcinoma Cell Culture in a Microfluidically Controlled Environment with a Static Molecular Gradient of Polyphenol

To study the simultaneous effect of the molecular gradient of polyphenols (curcumin, trans-resveratrol, and wogonin) and biological factors released from tumor cells on apoptosis of adjacent cells, a novel microfluidic system was designed and manufactured. The small height/volume of microfluidic culture chambers and static conditions allowed for establishing the local microenvironment and maintaining undisturbed concentration profiles of naturally secreted from cells biochemical factors. In all trials, we observe that these conditions significantly affect cell viability by stimulating cell apoptosis at lower concentrations of polyphenols than in traditional multiwell cultures. The observed difference varied between 20.4-87.8% for curcumin, 11.0-37.5% for resveratrol, and 21.7-62.2% for wogonin. At low concentrations of polyphenols, the proapoptotic substances released from adjacent cells, like protein degradation products, significantly influence cell viability. The mean increase in cell mortality was 38.3% for microfluidic cultures. Our research has also confirmed that the gradient microsystem is useful in routine laboratory tests in the same way as a multiwell plate and may be treated as its replacement in the future. We elaborated the new repetitive procedures for cell culture and tests in static gradient conditions, which may become a gold standard of new drug investigations in the future.

Fascinating Chemopreventive Story of Wogonin: A Chance to Hit on the Head in Cancer Treatment

Cancer, global havoc, is a group of debilitating diseases that strikes family as well as society. Cancer cases are drastically increasing these days. Despite many therapies and surgical procedures available, cancer is still difficult to control due to limited effective therapies or targeted therapies. Natural products can produce lesser side effects to the normal cells, which are the major demerit of chemotherapies and radiation. Wogonin, a natural product extracted from the plant, Scutellaria baicalensis has been widely studied and found with a high caliber to tackle most of the cancers via several mechanisms that include intrinsic as well as extrinsic apoptosis signaling pathways, carcinogenesis diminution, telomerase activity inhibition, metastasis inhibition in the inflammatory microenvironment, anti-angiogenesis, cell growth inhibition and arrest of the cell cycle, increased generation of H₂O₂ and accumulation of Ca²⁺ and also as an adjuvant along with anticancer drugs. This article discusses the role of wogonin in various cancers, its synergism with various drugs, and the mechanism by which wogonin controls tumor growth.

Baicalein Is a Phytohormone that Signals Through the Progesterone and Glucocorticoid Receptors

While flavonoids have been studied extensively for estrogen receptor activity, they have not been well studied for their ability to modify progesterone receptor (PR) and glucocorticoid receptor (GR) signaling. Three flavonoid compounds, tangeretin, wogonin, and baicalein, were selected for testing for PR and GR activity based on their structural similarity to known phytoprogesterone-like compounds. Each compound was docked in the binding pocket of PR and GR. Of these compounds, baicalein was predicted to be most likely to bind to both receptors. A fluorescence polarization competitive binding assay for PR and GR confirmed that baicalein binds to both the PR and GR with IC₅₀ values of 15.30 μM and 19.26 μM, respectively. In Ishikawa PR-B and T47D cells, baicalein acted as a PR antagonist in a hormone response element (HRE) luciferase (Luc) assay. In OVCAR5 cells, which only express GR, baicalein was a GR agonist via an HRE/Luc assay and induced GR target genes, FKBP5 and GILZ. RU486, a PR and GR antagonist, abrogated baicalein's activity in OVCAR5 cells, confirming baicalein's activity is mediated through the GR. In vivo, baicalein administered intraperitoneally to female mice twice a week for 4 weeks at a dose of 25 mg/kg induced the GR target gene GILZ in the reproductive tract, which was blocked by RU486. In summary, baicalein has PR antagonist and GR agonist activity in vitro and demonstrates GR agonist activity in the uterus in vivo.

Methylwogonin exerts anticancer effects in A375 human malignant melanoma cells through apoptosis induction, DNA damage, cell invasion inhibition and downregulation of the mTOR/PI3K/Akt signalling pathway

INTRODUCTION

The main purpose of the present research was to study the anticancer effects of methylwogonin in A375 human malignant melanoma cells by evaluating its effects on apoptosis, DNA fragmentation, cancer cell invasion and the mTOR/PI3K/AKT signalling pathway.

MATERIAL AND METHODS

Effects on cell cytotoxicity were evaluated by MTT assay while a clonogenic assay determined the effects of methylwogonin on colony formation. Fluorescence microscopy evaluated apoptotic effects of methylwogonin in these cells using acridine orange/propidium iodide and Hoechst 33342 staining dyes. Gel electrophoresis evaluated the effects of methylwogonin on DNA fragmentation while the Matrigel invasion assay evaluated the effects of the drug on cancer cell invasion. Effects of methylwogonin on the mTOR/PI3K/AKT signalling pathway were evaluated by western blot assay.

RESULTS

Methylwogonin induces concentration-dependent as well as time-dependent growth inhibitory effects inducing significant cytotoxicity in these cancer cells. Methylwogonin led to dose-dependent inhibition of colony formation in A375 human malignant melanoma cells. The number of cell colonies decreased significantly as the methylwogonin dose increased from 0, 50, 150, to 300 μM. Methylwogonin treatment of cells at lower doses led to yellow fluorescence (early apoptosis), which changed to red/orange fluorescence, indicating late apoptosis at higher doses. Similar results were obtained using Hoechst 33342 staining, revealing that 50, 150 and 300 μM doses of methylwogonin led to significant morphological changes including chromatin condensation, fragmented nuclei and cellular shrinkage. DNA ladder formation was also observed, and this effect increased with increasing doses of methylwogonin. Methylwogonin also inhibited cancer cell invasion in a dose-dependent manner.

CONCLUSIONS

Different doses of methylwogonin led to concentration-dependent downregulation of phosphorylated PI3K, AKT and mTOR.

Anticancer Effects of Baicalein in FRO Thyroid Cancer Cells Through the Up-regulation of ERK/p38 MAPK and Akt Pathway

BACKGROUND/AIM

The aim of the study was to evaluate the anticancer effects of baicalein in FRO anaplastic thyroid cancer (ATC) cells.

MATERIALS AND METHODS

FRO cells were treated with baicalein and viability was measured by the MTT assay. Cell apoptosis was observed by staining with Hoechst dye. The expression of apoptotic proteins (Bax, Bcl-2, PARP, cytochrome c, and caspase-3) and the inflammatory protein Cox-2 and the phosphorylation of MAPKs and Akt were determined by western blot.

RESULTS

Treatment with baicalein inhibited cell proliferation in a time-dependent manner and increased DNA fragmentation and apoptosis in FRO cells. Baicalein at 50 and 100 μM inhibited the expression of Bax, PARP, cytochrome c, cleaved caspase-3, and Cox-2, and increased the expression of Bcl-2. Baicalein increased the phosphorylation of ERK, p38 MAPK, and Akt and decreased JNK phosphorylation.

CONCLUSION

Baicalein caused anticancer effects in FRO ATC cells through induction of apoptosis and regulation of the MAPK and Akt pathway.

Active compounds present inRosmarinus officinalis leaves andScutellaria baicalensis root evaluated as new therapeutic agents for endometriosis

RESEARCH QUESTION

Can carnosic acid, (CA) rosmarinic acid (RA) and wogonin (WG) inhibit the growth of cultured human endometrial stromal cells and endometriotic-like lesions induced in a BALB/c model of endometriosis?

DESIGN

Primary stromal cell cultures were established from endometrial biopsies from women with endometriosis and controls. The human endometrial stromal cell line T-HESC was also used for in-vitro experiments. Endometriosis was surgically induced in BALB/c mice, which were randomly assigned to CA 2 mg/kg/day (n = 11); CA 20 mg/kg/day (n = 10); RA 1 mg/kg/day (n = 11); RA 3 mg/kg/day (n = 10); WG 20 mg/kg/day (n = 12); intraperitoneal vehicle control (n = 8) or oral vehicle control (n = 11). After surgery, CA and RA were administered intraperitoneally on days 14-28. WG was administered orally by intragastric gavage on days 14-26.

RESULTS

CA, RA and WG significantly inhibited in-vitro cell proliferation in primary and T-HESC cell cultures (P < 0.05). CA and WG induced cell cycle arrest of T-HESC at the G2/M phase (P < 0.01). RA reduced intracellular ROS accumulation (P < 0.001), whereas WG increased it (P < 0.05). WG significantly inhibited oestrogen receptor alpha expression in T-HESC (P < 0.01). In-vivo, CA, RA and WG significantly reduced lesions size (P < 0.05). All compounds significantly decreased the percentage of cells in proliferation (P < 0.05) whereas RA and WG further increased the percentage of apoptotic cells (P < 0.05) in endometriotic-like lesions.

CONCLUSIONS

The results are promising; further investigation of these compounds as new therapeutics is needed.

Scutellaria: Debates on the anticancer property

The widespread use of plants as accessible anticancer agents leads to the identification of many natural source chemotherapeutic agents. Scutellaria one of the popular genus of flowering plants has been used for various human illnesses for thousands of years. Scutellaria has anti-metastatic, anti-proliferative, anti-invasion, anti-angiogenic and apoptosis effects in vitro as well as in vivo. Despite numerous reports on the cytotoxic-antitumor activity of the plant, there are still some issues need further consideration. Issues such as unjustified interpretations, lack of attention to the pharmacokinetics profile and weak study design may affect the final decision about the use of plants as anticancer agents and possibly needs reconsideration. In this review, we have summarized the potential health benefits of Scutellaria and its active components also the underlying mechanism of cytotoxicity and antitumor activity. Meanwhile we have discussed concerns may interfere with the precise conclusion.

Scutellaria baicalensis and Cancer Treatment: Recent Progress and Perspectives in Biomedical and Clinical Studies

Scutellaria baicalensis (Huangqin in Chinese) is a major traditional Chinese medicine (TCM) herb, which has a long history of use in the treatment of a variety of symptoms correlated with cancer. In the past decade, the potential of S. baicalensis and single compounds derived from it as anticancer agents targeting various pathways has received extensive research attention. Specifically, the proliferation and metastases inhibiting properties of the single compounds in cancer have been studied; however, the underlying mechanisms remain unclear. This review summarizes the various mechanisms, pathways and molecular targets involved in the anticancer activity of S. baicalensis and its single compounds. However, the aim of this review is to provide a more thorough view of the last 10 years to link traditional use with modern research and to highlight recently discovered molecular mechanisms. Extracts and major flavonoids derived from S. baicalensis have been found to possess anticancer effects in multiple cancer cell lines both in vitro and in vivo. Further investigation is warranted to better understand the underlying mechanisms and to discover novel targets and cancer therapeutic drugs that may improve both the survival and quality of life of cancer patients.

Reactive oxygen species induction by cabazitaxel through inhibiting Sestrin-3 in castration resistant prostate cancer

Reactive oxygen species (ROS) production induced by taxanes in cancer cells may influence the taxane-induced cell death or the drug resistance. We investigated the correlation between the cytotoxic effect of taxanes and ROS production in human castration-resistant prostate cancer (CRPC) cell lines. Three human prostate cancer cell lines were treated with increasing concentrations of docetaxel or cabazitaxel in vitro. Cabazitaxel showed significantly higher cytotoxic efficacy than docetaxel in human CRPC cells, accompanied by elevated ROS production detected by FACS analysis. To investigate whether cabazitaxel-mediated cell death was caused by the ROS generation induced by cabazitaxel, we treated CRPC cells in the presence of antioxidant NAC. NAC reduced the cytotoxic effect induced by cabazitaxel. We found that ROS elimination by Sestrin-3 (SESN3) was significantly inhibited by cabazitaxel, but not by docetaxel. These results indicate higher sensitivity of human CRPC to cabazitaxel compared to docetaxel involves ROS production through inhibiting the expression of antioxidant enzyme SESN3.

High-dose wogonin exacerbates DSS-induced colitis by up-regulating effector T cell function and inhibiting Treg cell

Wogonin exerts anti‐tumour activities via multiple mechanisms. We have identified that high‐dose wogonin (50 or 100 mg/kg) could inhibit the growth of transplanted tumours by directly inducing tumour apoptosis and promoting DC, T and NK cell recruitment into tumour tissues to enhance immune surveillance. However, wogonin (20–50 μM) ex vivo prevents inflammation by inhibiting NF‐κB and Erk signalling of macrophages and epithelial cells. It is elusive whether high‐dose wogonin promotes or prevents inflammation. To investigate the effects of high‐dose wogonin on murine colitis induced by dextran sodium sulphate (DSS), mice were co‐treated with DSS and various doses of wogonin. Intraperitoneal administration of wogonin (100 mg/kg) exacerbated DSS‐induced murine colitis. More CD4⁺CD44⁺ and CD8⁺CD44⁺ cells were located in the inflamed colons in the wogonin (100 mg/kg) treatment group than in the other groups. Frequencies of CD4⁺CD25⁺CD127⁻ and CD4⁺CD25⁺ Foxp3⁺ cells in the colons and spleen respectively, were reduced by wogonin treatment. Ex vivo stimulations with high‐dose wogonin (50–100 μg/ml equivalent to 176–352 μM) could synergize with IL‐2 to promote the functions of CD4⁺ and CD8⁺ cells. However, regulatory T cell induction was inhibited. Wogonin stimulated the activation of NF‐κB and Erk but down‐regulated STAT3 phosphorylation in the CD4⁺ T cells. Wogonin down‐regulated Erk and STAT3‐Y705 phosphorylation in the regulatory T cells but promoted NF‐κB and STAT3‐S727 activation. Our study demonstrated that high‐dose wogonin treatments would enhance immune activity by stimulating the effector T cells and by down‐regulating regulatory T cells.

Wogonin Inhibits Tumor-derived Regulatory Molecules by Suppressing STAT3 Signaling to Promote Tumor Immunity

Wogonin exerts effective antitumor activities through direct cytotoxicity against cancer cells and indirect immune modulation. However, the molecular mechanisms of these activities remain poorly understood and need further study. We found that wogonin could efficiently downregulate the expression of B7H1, retinoic acid early induced transcript-1ε (RAE-1ε), and vascular endothelial growth factor in gastric cancer cells. Wogonin also promoted the secretion of calreticulin and high-mobility group protein 1 by tumor cells. Apoptotic bodies from dying tumor cells treated with wogonin were susceptible for uptake by neighboring dendritic cells (DCs). With the xenograft tumor model, wogonin inhibited tumor growth and promoted the recruitment of DC, T, and NK cells into tumor tissues. Infiltrated frequencies of DC, T, and NK cells in tumors were inversely correlated with expression levels of vascular endothelial growth factor, B7H1, and RAE-1ε of tumor tissues. Wogonin directly inhibited the activation of STAT3 on tyrosine 705 in tumor cells. The dephosphorylation of STAT3 contributed to the decreased expression of B7H1 and MHC class I chain-related protein A, and the enhancement of calreticulin on the cell membrane. Our study confirmed the immune-enhancing function of wogonin, and indicated that wogonin could be used in collaboration with DC vaccine or activated lymphocytes for tumor therapy.

Advances of wogonin, an extract from Scutellaria baicalensis, for the treatment of multiple tumors

As the major bioactive compound of Scutellaria baicalensis that has been approved to be effective as an anti-inflammatory and antiviral inhibitor in cardiovascular diseases, wogonin (WG) showed potent and promising antitumor effects both in vitro and in vivo. It has been proved that WG has the ability to inhibit the growth of tumor cells, induce apoptosis, and suppress angiogenesis. The molecular mechanisms involve reactive oxygen species, Ca²⁺, NF-κB, tumor necrosis factor-related apoptosis-inducing ligand, and tumor necrosis factor-alpha. Furthermore, the synergistic effect of WG with 5-fluorouracil, etoposide, and adriamycin to enhance chemotherapy and reverse drug resistance has also been confirmed. In this review, we summarize the advances in recent years on the antitumor effect of WG on multiple tumors; in addition, we also present information regarding the synergistic and chemosensitizing effects of WG with other drugs to illustrate its potential use in the clinic.

Mitochondrial Respiratory Dysfunction Induces Claudin-1 Expression via Reactive Oxygen Species-mediated Heat Shock Factor 1 Activation, Leading to Hepatoma Cell Invasiveness

Although mitochondrial dysfunction has been implicated in tumor metastasis, it is unclear how it regulates tumor cell aggressiveness. We have reported previously that human hepatoma cells harboring mitochondrial defects have high tumor cell invasion activity via increased claudin-1 (Cln-1) expression. In this study, we demonstrated that mitochondrial respiratory defects induced Cln-1 transcription via reactive oxygen species (ROS)-mediated heat shock factor 1 (HSF1) activation, which contributed to hepatoma invasiveness. We first confirmed the inverse relationship between mitochondrial defects and Cln-1 induction in SNU hepatoma cells and hepatocellular carcinoma tissues. We then examined five different respiratory complex inhibitors, and complex I inhibition by rotenone most effectively induced Cln-1 at the transcriptional level. Rotenone increased both mitochondrial and cytosolic ROS. In addition, rotenone-induced Cln-1 expression was attenuated by N-acetylcysteine, an antioxidant, and exogenous H2O2 treatment was enough to increase Cln-1 transcription, implying the involvement of ROS. Next we found that ROS-mediated HSF1 activation via hyperphosphorylation was the key event for Cln-1 transcription. Moreover, the Cln-1 promoter region (from -529 to +53) possesses several HSF1 binding elements, and this region showed increased promoter activity and HSF1 binding affinity in response to rotenone treatment. Finally, we demonstrated that the invasion activity of SNU449 cells, which harbor mitochondrial defects, was blocked by siRNA-mediated HSF1 knockdown. Taken together, these results indicate that mitochondrial respiratory defects enhance Cln-1-mediated hepatoma cell invasiveness via mitochondrial ROS-mediated HSF1 activation, presenting a potential role for HSF1 as a novel mitochondrial retrograde signal-responsive transcription factor to control hepatoma cell invasiveness.

The palladacycle, AJ-5, exhibits anti-tumour and anti-cancer stem cell activity in breast cancer cells

Breast cancer is the most common malignancy amongst women worldwide but despite enormous efforts to address this problem, there is still limited success with most of the current therapeutic strategies. The current study describes the anti-cancer activity of a binuclear palladacycle complex (AJ-5) in oestrogen receptor positive (MCF7) and oestrogen receptor negative (MDA-MB-231) breast cancer cells as well as human breast cancer stem cells. AJ-5 is shown to induce DNA double strand breaks leading to intrinsic and extrinsic apoptosis and autophagy cell death pathways which are mediated by the p38 MAP kinase. This study provides evidence that AJ-5 is potentially an effective compound in the treatment of breast cancer.

Cytotoxicity of dietary flavonoids on different human cancer types

Flavonoids are ubiquitous in nature. They are also in food, providing an essential link between diet and prevention of chronic diseases including cancer. Anticancer effects of these polyphenols depend on several factors: Their chemical structure and concentration, and also on the type of cancer. Malignant cells from different tissues reveal somewhat different sensitivity toward flavonoids and, therefore, the preferences of the most common dietary flavonoids to various human cancer types are analyzed in this review. While luteolin and kaempferol can be considered as promising candidate agents for treatment of gastric and ovarian cancers, respectively, apigenin, chrysin, and luteolin have good perspectives as potent antitumor agents for cervical cancer; cells from main sites of flavonoid metabolism (colon and liver) reveal rather large fluctuations in anticancer activity probably due to exposure to various metabolites with different activities. Anticancer effect of flavonoids toward blood cancer cells depend on their myeloid, lymphoid, or erythroid origin; cytotoxic effects of flavonoids on breast and prostate cancer cells are highly related to the expression of hormone receptors. Different flavonoids are often preferentially present in certain food items, and knowledge about the malignant tissue-specific anticancer effects of flavonoids could be purposely applied both in chemoprevention as well as in cancer treatment.

Wogonin has multiple anti-cancer effects by regulating c-Myc/SKP2/Fbw7α and HDAC1/HDAC2 pathways and inducing apoptosis in human lung adenocarcinoma cell line A549

Wogonin is a plant monoflavonoid which has been reported to inhibit cell growth and/or induce apoptosis in various tumors. The present study examined the apoptosis-inducing activity and underlying mechanism of action of wogonin in A549 cells. The results showed that wogonin was a potent inhibitor of the viability of A549 cells. Apoptotic protein changes detected after exposure to wogonin included decreased XIAP and Mcl-1 expression, increased cleaved-PARP expression and increased release of AIF and cytotchrome C. Western blot analysis showed that the activity of c-Myc/Skp2 and HDAC1/HDAC2 pathways, which play important roles in tumor progress, was decreased. Quantitative PCR identified increased levels of c-Myc mRNA and decreased levels of its protein. Protein levels of Fbw7α, GSK3β and Thr58-Myc, which are involved in c-Myc ubiquitin-dependent degradation, were also analyzed. After exposure to wogonin, Fbw7α and GSK3β expression decreased and Thr58-Myc expression increased. However, MG132 was unable to prevent c-Myc degradation. The present results suggest that wogonin has multiple anti-cancer effects associated with degradation of c-Myc, SKP2, HDAC1 and HDAC2. Its ability to induce apoptosis independently of Fbw7α suggests a possible use in drug-resistance cancer related to Fbw7 deficiency. Further studies are needed to determine which pathways are related to c-Myc and Fbw7α reversal and whether Thr58 phosphorylation of c-Myc is dependent on GSK3β.

Wogonin induces apoptosis by suppressing E6 and E7 expressions and activating intrinsic signaling pathways in HPV-16 cervical cancer cells

Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells.

Decreased mitochondrial OGG1 expression is linked to mitochondrial defects and delayed hepatoma cell growth

Many solid tumor cells exhibit mitochondrial respiratory impairment; however, the mechanisms of such impairment in cancer development remain unclear. Here, we demonstrate that SNU human hepatoma cells with declined mitochondrial respiratory activity showed decreased expression of mitochondrial 8-oxoguanine DNA glycosylase/lyase (mtOGG1), a mitochondrial DNA repair enzyme; similar results were obtained with human hepatocellular carcinoma tissues. Among several OGG1-2 variants with a mitochondrial-targeting sequence (OGG1-2a, -2b, -2c, -2d, and -2e), OGG1-2a was the major mitochondrial isoform in all examined hepatoma cells. Interestingly, hepatoma cells with low mtOGG1 levels showed delayed cell growth and increased intracellular reactive oxygen species (ROS) levels. Knockdown of OGG1-2 isoforms in Chang-L cells, which have active mitochondrial respiration with high mtOGG1 levels, significantly decreased cellular respiration and cell growth, and increased intracellular ROS. Overexpression of OGG1-2a in SNU423 cells, which have low mtOGG1 levels, effectively recovered cellular respiration and cell growth activities, and decreased intracellular ROS. Taken together, our results suggest that mtOGG1 plays an important role in maintaining mitochondrial respiration, thereby contributing to cell growth of hepatoma cells.

Differential functions of C- and N-terminal hepatitis B x protein in liver cells treated with doxorubicin in normoxic or hypoxic condition

Hepatitis viral B x protein (HBx), a hepatocarcinogen, is frequently mutated. Hypoxia influences the growth of HCC and also the sensitivity of tumor cells to treatments. We aimed to test the role of HBx and acute hypoxia in the efficacy of chemotherapy. In this study, we established 4 Chang liver cell lines with the full-length HBx (HBx), the first 50 amino acids of N-terminal HBx (HBx/50), the last 104 amino acids of C-terminal HBx (HBx/51) and empty vector (CL), respectively. MTT and TNUEL assays were used to assess cell viability and apoptosis respectively. Western blot was used to determine the expression of relevant proteins. Results showed that among 4 cell lines, doxorubicin was most effective in decreasing the viability and enhancing apoptosis in HBx/51 cells, while HBx/50 cells were most resistant to the treatment. Cells in hypoxia were more susceptible to doxorubicin than cells in normoxia. Hypoxia facilitated the Bid cleavage especially in HBx/51 cells via phosphorylating p38 MAPK. p38 MAPK inhibitor significantly reduced the tBid level and increased cell viability. In conclusion, N-terminal HBx and C-terminal HBx function differentially in their ability to regulate cell growth, with the former being promotive but the latter being inhibitory. The acute hypoxia may overcome the HBx-induced resistance and facilitate the chemotherapy.

Polygonum cuspidatum Extract Induces Anoikis in Hepatocarcinoma Cells Associated with Generation of Reactive Oxygen Species and Downregulation of Focal Adhesion Kinase

Anoikis has been recognized as a potential target for anticancer therapy. Polygonum cuspidatum (Huzhang) is a frequently used Chinese herb in hepatocarcinoma. In present study, we evaluated the effects of Polygonum cuspidatum extract (PCE) in hepatocarcinoma cells in suspension. The results showed that PCE inhibited the proliferation of hepatocarcinoma cells in suspension in a dose- and time-dependent manner. PCE also inhibited anchorage-independent growth of hepatocarcinoma cells in soft agar. PCE induced anoikis in human hepatocarcinoma Bel-7402 cells accompanied by caspase-3 and caspase-9 activation and poly(ADP-ribose) polymerase cleavage, which was completely abrogated by a pan caspase inhibitor, Z-VAD-FMK. In addition, PCE treatment induced intracellular reactive oxygen species (ROS) production in Bel-7402 cells. NAC, an ROS scavenger, partially attenuated PCE-induced anoikis and activation of caspase-3 and caspase-9. Furthermore, PCE inhibited expression of focal adhesion kinase (FAK) in Bel-7402 cells. Overexpression of FAK partially abrogated PCE-induced anoikis. These data suggest that PCE may inhibit suspension growth and induce caspase-mediated anoikis in hepatocarcinoma cells and may relate to ROS generation and FAK downregulation. The present study provides new insight into the application of Chinese herb for hepatocarcinoma treatment.

Galloflavin, a new lactate dehydrogenase inhibitor, induces the death of human breast cancer cells with different glycolytic attitude by affecting distinct signaling pathways

Galloflavin (GF), a recently identified lactate dehydrogenase inhibitor, hinders the proliferation of cancer cells by blocking glycolysis and ATP production. The aim of the present experiments was to study the effect of this compound on breast cancer cell lines reproducing different pathological subtypes of this tumor: MCF-7 (the well differentiated form), MDA-MB-231 (the aggressive triple negative tumor) and MCF-Tam (a sub-line of MCF-7 with acquired tamoxifen resistance). We observed marked differences in the energetic metabolism of these cell lines. Compared to MCF-7 cells, both MDA-MB-231 and MCF-Tam cells exhibited higher LDH levels and glucose uptake and showed lower capacity of oxygen consumption. In spite of these differences, GF exerted similar growth inhibitory effects. This result was explained by the finding of a constitutively activated stress response in MDA-MB-231 and MCF-Tam cells, which reproduce the poor prognosis tumor forms. As a further proof, different signaling pathways were found to be involved in the antiproliferative action of GF. In MCF-7 cells we observed a down regulation of the ERα-mediated signaling needed for cell survival. On the contrary, in MCF-Tam and MDA-MB-231 cells growth inhibition appeared to be contributed by an oxidative stress condition. The prevalent mechanism of cell death was found to be apoptosis induction. Because of the clinical relevance of breast cancer forms having the triple negative and/or chemoresistant phenotype, our results showing comparable effects of GF even on aggressively growing cells encourage further studies to verify the potential of this compound in improving the chemotherapy of breast cancer.

Wogonin induces reactive oxygen species production and cell apoptosis in human glioma cancer cells

Glioma is the most common primary adult brain tumor with poor prognosis because of the ease of spreading tumor cells to other regions of the brain. Cell apoptosis is frequently targeted for developing anti-cancer drugs. In the present study, we have assessed wogonin, a flavonoid compound isolated from Scutellaria baicalensis Georgi, induced ROS generation, endoplasmic reticulum (ER) stress and cell apoptosis. Wogonin induced cell death in two different human glioma cells, such as U251 and U87 cells but not in human primary astrocytes (IC 50 > 100 μM). Wogonin-induced apoptotic cell death in glioma cells was measured by propidine iodine (PI) analysis, Tunnel assay and Annexin V staining methods. Furthermore, wogonin also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Moreover, treatment of wogonin also increased a number of signature ER stress markers glucose-regulated protein (GRP)-78, GRP-94, Calpain I, and phosphorylation of eukaryotic initiation factor-2α (eIF2α). Treatment of human glioma cells with wogonin was found to induce reactive oxygen species (ROS) generation. Wogonin induced ER stress-related protein expression and cell apoptosis was reduced by the ROS inhibitors apocynin and NAC (N-acetylcysteine). The present study provides evidence to support the fact that wogonin induces human glioma cell apoptosis mediated ROS generation, ER stress activation and cell apoptosis.

Effects of curcumin on bleomycin‑induced oxidative stress in malignant testicular germ cell tumors

Bleomycin is commonly used in the treatment of testicular cancer. Bleomycin generates oxygen radicals, induces the oxidative cleavage of DNA strands and induces cancer cell apoptosis. Curcumin (diferuloylmethane) is a potent antioxidant and chief component of the spice turmeric. No study investigating the effects of curcumin on intrinsic and bleomycin-induced oxidative stress in testicular germ cell tumors has been reported in the literature. For this reason, the present study aimed to examine the effects of curcumin on oxidative stress produced in wild-type NTera-2 and p53-mutant NCCIT testicular cancer cells incubated with bleomycin and the results were compared with cells treated with H2O2 which directly produces oxidative stress. The protein carbonyl content, thiobarbituric acid reactive substances (TBARS), glutathione (GSH), 8-isoprostane, lipid hydroperoxide (LPO) levels and total antioxidant capacity in the two testicular cancer cell lines were determined. Results showed that bleomycin and H2O2 significantly increased protein carbonyl, TBARS, 8-isoprostane and LPO levels in the NTera-2 and NCCIT cell lines. Bleomycin and H2O2 significantly decreased the antioxidant capacity and GSH levels in NTera-2 cells. Curcumin significantly decreased LPO, 8-isoprostane and protein carbonyl content, and TBARS levels increased in cells treated with bleomycin and H2O2. Curcumin enhanced GSH levels and the antioxidant capacity of NTera-2 cells. In conclusion, curcumin inhibits bleomycin and H2O2-induced oxidative stress in human testicular cancer cells.

In vitro and in vivo evaluation of the genotoxicity of Gumiganghwal-tang, a traditional herbal prescription

ETHNOPHARMACOLOGICAL RELEVANCE

Gumiganghwal-tang (GGT, known as Kumi-Kyokatsu-to in Japanese) is a traditional herbal prescription made from nine different herbs that is used for the treatment of the common cold, pain, and inflammatory diseases.

AIM OF THE STUDY

This study evaluated the potential genotoxicity of an aqueous GGT extract using three standard battery of tests as part of a safety evaluation.

MATERIALS AND METHODS

We prepared GGT using a water extraction method and subsequently extracted six compounds from GGT by high performance liquid chromatography. GGT extract genotoxicity was assayed using three standard tests including the in vitro bacterial reverse mutation test, the in vitro chromosomal aberration test with Chinese hamster lung cells, and the in vivo micronucleus test using ICR mouse bone marrow recommended by the Korean Food and Drug Administration.

RESULTS

The bacterial reverse mutation assay showed that GGT extract doses ranging from 333.3 up to 5000mg/plate induced a greater than 2-fold increase in the number of revertant TA1537 strain colonies exhibiting metabolic activation (with S-9 mix), when compared with the vehicle control. The chromosomal aberration test showed that GGT extract induced an increase in the number of chromosomal aberrations after treatment for 6h with the S-9 mix and 22h without the S-9 mix, when compared with vehicle control. In contrast, the micronucleus test showed that GGT extract did not significantly increase the number of micronucleated polychromatic erythrocytes (MNPCEs) in ICR mouse bone marrow.

CONCLUSIONS

Based on these results, it was concluded that GGT extract acted as a genotoxic material in our experimental conditions. We did not identify the compounds responsible for the induction of genotoxic effects, but it was significant that we provided a basic genotoxicity profile for GGT.

Prostaglandin E2 blocks menadione-induced apoptosis through the Ras/Raf/Erk signaling pathway in promonocytic leukemia cell lines

Altered oxidative stress has long been observed in cancer cells, and this biochemical property of cancer cells represents a specific vulnerability that can be exploited for therapeutic benefit. The major role of an elevated oxidative stress for the efficacy of molecular targeted drugs is under investigation. Menadione is considered an attractive model for the study of oxidative stress, which can induce apoptosis in human leukemia HL-60 cell lines. Prostaglandin E(2) (PGE(2)) via its receptors not only promotes cell survival but also reverses apoptosis and promotes cancer progression. Here, we present evidence for the biological role of PGE(2) as a protective agent of oxidative stress-induced apoptosis in monocytic cells. Pretreatment of HL-60 cells with PGE(2) markedly ameliorated the menadione-induced apoptosis and inhibited the degradation of PARP and lamin B. The EP(2) receptor antagonist AH6809 abrogated the inhibitory effect of PGE(2), suggesting the role of the EP(2)/cAMP system. The PKA inhibitor H89 also reversed apoptosis and decreased the PKA activity that was elevated 10-fold by PGE(2). The treatment of HL-60 cells with NAC or zinc chloride showed a similar protective effect as with PGE(2) on menadione-treated cells. Furthermore, PGE(2) activated the Ras/Raf/MEK pathway, which in turn initiated ERK activation, and ultimately protected menadione-induced apoptosis. These results imply that PGE(2) via cell survival pathways may protect oxidative stress-induced apoptosis in monocytic cells. This study warrants further pre-clinical investigation as well as application towards leukemia clinics.

The genome-wide expression profile of 1,2,3,4,6-penta-O-galloyl-β-D-glucose-treated MDA-MB-231 breast cancer cells: molecular target on cancer metabolism

1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG), a polyphenolic compound isolated from Rhus chinensis Mill. PGG has been known to have anti-tumor, anti-angiogenic and anti-diabetic activities. The present study revealed another underlying molecular target of PGG in MDA-MB-231 breast cancer cells by using Illumina Human Ref-8 expression BeadChip assay. Through the Beadstudio v3 micro assay program to compare the identified genes expressed in PGG-treated MDA-MB-231 cells with untreated control, we found several unique genes that are closely associated with pyruvate metabolism, glycolysis/gluconeogenesis and tyrosine metabolism, including PC, ACSS2, ACACA, ACYP2, ALDH3B1, FBP1, PRMT2 and COMT. Consistent with microarray data, real-time RT-PCR confirmed the significant down-regulation of these genes at mRNA level in PGG-treated MDA-MB-231 cells. Our findings suggest the potential of PGG as anticancer agent for breast cancer cells by targeting cancer metabolism genes.