Raf and PI3K are the molecular targets for the anti-metastatic effect of luteolin

Mechanism of Dahuang-Dangshen drug pairs in the treatment of HCC based on network pharmacology, bioinformatics, molecular docking and experimental verification

The anti-hepatocellular carcinoma (HCC) effect of the active ingredients of natural Chinese herbal medicine has become a hot topic at home and abroad. A list of studies evidence the therapeutic efficacy of Dahuang (DH) or Dangshen (DS) against HCC, but the combination effect of DH and DS in HCC treatment is rarely reported and the molecular mechanism of the drug pairs is not yet clear. Therefore, in this study, the combined effects and potential mechanisms of DH and DS drug pairs were investigated through network pharmacology, bioinformatics, molecular docking, and a series of pharmacological experiments, including the MTT assay, clone formation, wound healing, JC-1 staining, and western blotting. In total, 140 intersection targets between the DH-DS drug pairs and HCC were identified. In the PPI network, the top ten hub targets with the highest node connection values were VEGFA, AKT, CTNNB1, EGFR, TNF, CASP3, HRAS, SRC, JUN, and ESR1. GO functional and KEGG pathway enrichment analysis involved 289 biological processes, 33 cellular components, 57 molecular functions, and 143 signaling pathways. Bioinformatic analysis indicated that EGFR and AKT were promising candidate genes that can serve as diagnostic and prognostic biomarkers for HCC. β-sitosterol from the DH drug and luteolin from the DS drug were found as promising small molecules for HCC. The experimental results showed that the combination of β-sitosterol and luteolin was more potent in suppressing cell proliferation, migration and inducing cell apoptosis when compared to β-sitosterol or luteolin alone. The western blot and molecular docking studies demonstrated that the potential mechanism may be related to the EGFR/AKT signaling pathway. In summary, the combination of DH and DS may resist cell proliferation, migration and promote apoptosis activity through the EGFR/AKT signaling pathway, which provides new insights for further exploring plant extract treatment for HCC.

Antioxidative and Anticancer Potential of Luteolin: A Comprehensive Approach Against Wide Range of Human Malignancies

Luteolin is widely distributed phytochemical, a flavonoid, in kingdom plantae. Luteolin with potential antioxidant activity prevent ROS-induced damages and reduce oxidative stress which is mainly responsible in pathogenesis of many diseases. Several chemo preventive activities and therapeutic benefits are associated with luteolin. Luteolin prevents cancer via modulation of numerous pathways, that is, by inactivating proteins; such as procaspase-9, CDC2 and cyclin B or upregulation of caspase-9 and caspase-3, cytochrome C, cyclin A, CDK2, and APAF-1, in turn inducing cell cycle arrest as well as apoptosis. It also enhances phosphorylation of p53 and expression level of p53-targeted downstream gene. By Increasing BAX protein expression; decreasing VEGF and Bcl-2 expression it can initiate cell cycle arrest and apoptosis. Luteolin can stimulate mitochondrial-modulated functions to cause cellular death. It can also reduce expression levels of p-Akt, p-EGFR, p-Erk1/2, and p-STAT3. Luteolin plays positive role against cardiovascular disorders by improving cardiac function, decreasing the release of inflammatory cytokines and cardiac enzymes, prevention of cardiac fibrosis and hypertrophy; enhances level of CTGF, TGFβ1, ANP, Nox2, Nox4 gene expressions. Meanwhile suppresses TGFβ1 expression and phosphorylation of JNK. Luteolin helps fight diabetes via inhibition of alpha-glucosidase and ChE activity. It can reduce activity levels of catalase, superoxide dismutase, and GS4. It can improve blood glucose, insulin, HOMA-IR, and HbA1c levels. This review is an attempt to elaborate molecular targets of luteolin and its role in modulating irregularities in cellular pathways to overcome severe outcomes during diseases including cancer, cardiovascular disorders, diabetes, obesity, inflammation, Alzheimer's disease, Parkinson's disease, hepatic disorders, renal disorders, brain injury, and asthma. As luteolin has enormous therapeutic benefits, it could be a potential candidate in future drug development strategies.

Progress, pharmacokinetics and future perspectives of luteolin modulating signaling pathways to exert anticancer effects: A review

Luteolin (3, 4, 5, 7-tetrahydroxyflavone) are natural flavonoids widely found in vegetables, fruits and herbs, with anti-tumor, anti-inflammatory and antioxidant effects, and also play an anti-cancer effect in various cancers such as lung, breast, prostate, and liver cancer, etc. Specifically, the anti-cancer mechanism includes regulation of various signaling pathways to induce apoptosis of tumor cells, inhibition of tumor cell proliferation and metastasis, anti-angiogenesis, regulation of immune function, synergistic anti-cancer drugs and regulation of reactive oxygen species levels of tumor cells. Specific anti-cancer mechanisms include regulation of various signaling pathways to induce apoptosis, inhibition of tumor cell proliferation and metastasis, anti-angiogenesis, reversal of epithelial-mesenchymal transition, regulation of immune function, synergism with anti-cancer drugs and regulation of reactive oxygen species levels in tumor cells. This paper integrates the latest cutting-edge research on luteolin and combines it with the prospect of future clinical applications, aiming to explore the mechanism of luteolin exerting different anticancer effects through the regulation of different signaling pathways, so as to provide a practical theoretical basis for the use of luteolin in clinical treatment and hopefully provide some reference for the future research direction of luteolin.

Target discovery of bioactive natural products with native-compound-coupled CNBr-activated Sepharose 4B beads (NCCB): Applications, mechanisms and outlooks

Natural products (NPs) represent a treasure trove for drug discovery and development due to their chemical structural diversity and a broad spectrum of biological activities. Uncovering the biological targets and understanding their molecular mechanism of actions are crucial steps in the development of clinical therapeutics. However, the structural complexity of NPs and intricate nature of biological system present formidable challenges in target identification of NPs. Although significant advances have been made in the development of new chemical tools, these methods often require high levels of synthetic skills for preparing chemical probes. This can be costly and time-consuming relaying on operationally complicated procedures and instruments. In recent efforts, we and others have successfully developed an operationally simple and practical chemical tool known as native-compound-coupled CNBr-activated Sepharose 4B beads (NCCB) for NP target identification. In this approach, a native compound readily reacts with commercial CNBr-activated Sepharose 4B beads with a process that is easily performed in any biology laboratory. Based on NCCB, our group has identified the direct targets of more than 60 NPs. In this review, we will elucidate the application scopes, including flavonoids, quinones, terpenoids and others, characteristics, chemical mechanisms, procedures, advantages, disadvantages, and future directions of NCCB in specific target discovery.

Multi-Faceted Role of Luteolin in Cancer Metastasis: EMT, Angiogenesis, ECM Degradation and Apoptosis

Luteolin (3',4',5,7-tetrahydroxyflavone), a member of the flavonoid family derived from plants and fruits, shows a wide range of biomedical applications. In fact, due to its anti-inflammatory, antioxidant and immunomodulatory activities, Asian medicine has been using luteolin for centuries to treat several human diseases, including arthritis, rheumatism, hypertension, neurodegenerative disorders and various infections. Of note, luteolin displays many anti-cancer/anti-metastatic properties. Thus, the purpose of this review consists in highlighting the relevant mechanisms by which luteolin inhibits tumor progression in metastasis, i.e., affecting epithelial-mesenchymal transition (EMT), repressing angiogenesis and lysis of extracellular matrix (ECM), as well as inducing apoptosis.

Phenolic Phytochemicals for Prevention and Treatment of Colorectal Cancer: A Critical Evaluation of In Vivo Studies

Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.

Natural Polyphenols for Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a prevalent and serious gastrointestinal malignancy with high mortality and morbidity. Chemoprevention refers to a newly emerged strategy that uses drugs with chemopreventive properties to promote antioxidation, regulate cancer cell cycle, suppress proliferation, and induce cellular apoptosis, so as to improve cancer treatment outcomes. Natural polyphenols are currently recognized as a class of chemopreventive agents that have shown remarkable anticarcinogenic properties. Numerous in vitro and in vivo studies have elucidated the anti-CRC mechanisms of natural polyphenols, such as regulation of various molecular and signaling pathways. Natural polyphenols are also reportedly capable of modulating the gut microbiota and cancer stem cells (CSCs) to suppress tumor formation and progression. Combined use of different natural polyphenols is recommended due to their low bioavailability and instability, and combination treatment can exert synergistical effects, reduce side effects, and avoid drug resistance in CRC treatment. In summary, the application of polyphenols in the chemoprevention and treatment of CRC is promising. Further clinical evaluation of their effectiveness is warranted and anticipated.

Luteolin, a Potent Anticancer Compound: From Chemistry to Cellular Interactions and Synergetic Perspectives

Increasing rates of cancer incidence and the toxicity concerns of existing chemotherapeutic agents have intensified the research to explore more alternative routes to combat tumor. Luteolin, a flavone found in numerous fruits, vegetables, and herbs, has exhibited a number of biological activities, such as anticancer and anti-inflammatory. Luteolin inhibits tumor growth by targeting cellular processes such as apoptosis, cell-cycle progression, angiogenesis and migration. Mechanistically, luteolin causes cell death by downregulating Akt, PLK-1, cyclin-B1, cyclin-A, CDC-2, CDK-2, Bcl-2, and Bcl-xL, while upregulating BAX, caspase-3, and p21. It has also been reported to inhibit STAT3 signaling by the suppression of STAT3 activation and enhanced STAT3 protein degradation in various cancer cells. Therefore, extensive studies on the anticancer properties of luteolin reveal its promising role in chemoprevention. The present review describes all the possible cellular interactions of luteolin in cancer, along with its synergistic mode of action and nanodelivery insight.

Synthesis of Four Steroidal Carbamates with Antitumor Activity against Mouse Colon Carcinoma CT26WT Cells: In Vitro and In Silico Evidence

Colorectal cancer (CRC) is one of the most lethal cancers worldwide. If detected on time, surgery can expand life expectations of patients up to five more years. However, if metastasis has grown deliberately, the use of chemotherapy can play a crucial role in CRC control. Moreover, the lack of selectivity of current anticancer drugs, plus mutations that occur in cancerous cells, demands the development of new chemotherapeutic agents. Several steroids have shown their potentiality as anticancer agents, while some other compounds, such as Taxol and its derivatives bearing a carbamate functionality, have reached the market. In this article, the synthesis, characterization, and antiproliferative activity of four steroidal carbamates on mouse colon carcinoma CT26WT cells are described. Carbamate synthesis occurred via direct reaction between diosgenin, its B-ring modified derivative, and testosterone with phenyl isocyanate under a Brønsted acid catalysis. All obtained compounds were characterized by ¹H and ¹³C Nuclear Magnetic Resonance (NMR), High Resolution Mass Spectroscopy (HRMS); their melting points are also reported. Results obtained from antiproliferative activity assays indicated that carbamates compounds have inhibitory effects on the growth of this colon cancer cell line. A molecular docking study carried out on Human Prostaglandin E Receptor (EP4) showed a high affinity between carbamates and protein, thus providing a valuable theoretical explanation of the in vitro results.

Identifying Active Compounds and Mechanisms of Citrus changshan-Huyou Y. B. Chang against URTIs-Associated Inflammation by Network Pharmacology in Combination with Molecular Docking

Purpose. The ripe fruits of Citrus changshan-huyou, known as Quzhou Fructus Aurantii (QFA), have been commonly used for respiratory diseases. The purpose of this study was to investigate their active compounds and demonstrate their mechanism in the treatment of upper respiratory tract infections (URTIs) through network pharmacology and molecular docking. Methods. The prominent compounds of QFA were acquired from TCMSP database. Their targets were retrieved from SwissTargetPrediction database, and target genes associated with URTIs were collected from DisGeNET and GeneCards databases. The target protein-protein interaction (PPI) network was constructed by using STRING database and Cytoscape. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were enriched. Visual compound-target-pathway network was established with Cytoscape. The effects of compounds were verified on the inhibitory activities against phosphoinositide 3-kinases (PI3Ks). Finally, the molecular docking was carried out to confirm the binding affinity of the bioactive compounds and target proteins. Results. Five important active compounds, naringenin (NAR), tangeretin (TAN), luteolin (LUT), hesperetin (HES), and auraptene (AUR), were obtained. The enrichment analysis demonstrated that the pathways associated with inflammation mainly contained PI3K/Akt signalling pathway, TNF signalling pathway, and so on. The most important targets covering inflammation-related proteins might be PI3Ks. In vitro assays and molecular docking exhibited that TAN, LUT, and AUR acted as PI3Kγ inhibitors. Conclusion. The results revealed that QFA could treat URTIs through a multi-compound, multi-target, multi-pathway network, in which TAN, LUT, and AUR acted as PI3Kγ inhibitors, probably contributing to a crucial role in treatment of URTIs.

Luteolin alleviates polycystic ovary syndrome in rats by resolving insulin resistance and oxidative stress

Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by elevated secretion of androgen, commonly associated with insulin resistance (IR), which could exacerbate patient with PCOS. Development of a safe and effective treatment in preventing and treating PCOS will be beneficial to women of reproductive age. Female Sprague-Dawley rats were randomly divided into four groups: sham group treated with vehicle (saline) or luteolin; letrozole and high-fat-diet-induced PCOS group treated with vehicle or luteolin (25, 50, 100 mg/kg ip). Ovary tissue and blood were collected for further analysis. Luteolin normalized estrus cycle and improved ovarian morphology, including reduced polycystic and alleviated the loss of oocytes and corpus luteum in PCOS rats. Serum follicle stimulating hormone and estradiol were reduced, whereas luteinizing hormone and testosterone were elevated in PCOS rats relative to that of sham, which were significantly normalized by luteolin. Notably, luteolin significantly inhibited IR and upregulated protein levels of PI3K p85α and pAKT compared with PCOS rats treated with vehicle. In addition, the activities of antioxidants such as SOD, GPx, CAT, and GSH were reduced in PCOS rats, which were significantly increased by luteolin. Protein and mRNA expressions of Nrf2 and downstream genes such as Hmox1 and Nqo1 were restored by luteolin in PCOS rats. Collectively, this study demonstrated that luteolin inhibited IR by prompting PI3K/AKT signaling pathway and enhanced antioxidative response through the restoration of Nrf2 pathway.NEW & NOTEWORTHY Luteolin normalizes the estrus cycle, ovarian morphological changes, improves serum sexual hormone levels, reduces insulin resistance, prompts PI3K/Akt signaling, improves antioxidative response, and upregulates Nrf2 signaling in PCOS rats. Luteolin has a potential to serve as a therapeutic agent in preventing and treating PCOS.

Luteolin-Fabricated ZnO Nanostructures Showed PLK-1 Mediated Anti-Breast Cancer Activity

The present work describes a facile and convenient procedure for synthesizing zinc oxide nanoparticles using luteolin isolated from Eclipta alba plant (L-ZnONPs) at room temperature. The formation of as-grown L-ZnONPs was confirmed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and selected area electron diffraction (SAED). The Wurtzite structure of ZnO was observed by its hexagonal phases in diffraction patterns. The SEM images revealed the different sizes and morphologies of L-ZnONPs, with diameters between 12 and 25 nm. The HR-TEM result showed that the inter-planar distance between two lattice fringes was 0.262 nm, which coincides with the d-spacing of (002) and (101) lattice planes of the as-obtained material. The anticancer activity of L-ZnONPs against the breast cancer cell line MCF-7 was greater as compared to that of luteolin or ZnO alone. The mechanistic evaluation of such an activity carried out using in silico methods suggested that the anti-breast cancer activity of L-ZnONPs was mediated by polo-like kinase 1 (PLK1) proteins.

Antigenotoxic, antiproliferative and antimetastatic properties of a combination of native medicinal plants from Argentina

ETHNOPHARMACOLOGICAL RELEVANCE

Jarilla is the common name of an appreciated group of native plants from the semi-arid region in Argentina (Larrea cuneifolia Cav., Larrea divaricata Cav. and Zuccagnia punctata Cav.) that have been historically consumed to heal respiratory, musculoskeletal and skin ailments, as well as recommended for weakness/tiredness, hypertension, diabetes and cancer treatment. It was previously reported that some biological properties could be improved when these plants are used jointly. Infusions of a defined mixture, composed by three Jarilla species, L. cuneifolia: L. divaricata: Z. punctata (0.5:0.25:0.25) (HM2) showed synergistic and additive effect on antioxidant activity even after passing through the gastro-duodenal tract.

AIM OF THE STUDY

The main purpose of this work was to evaluate antigenotoxic, antitumor, and anti-metastatic properties of the Jarilla species that grow in the Northwest of Argentina and a herbal combination of them.

MATERIAL AND METHODS

Infusions of Jarilla mixture (HM2), and of each single plant species were prepared. Phenolic profiles of infusions were analyzed by HPLC-ESI-MS/MS and two relevant chemical markers were quantified. The antigenotoxic activity was evaluated by using the Ames test and the Cytokinesis-Block Micronucleus (CBMN) assay against direct mutagens. Evaluations of both cytotoxicity and antiproliferative effects were conducted on tumor and non-tumor cell lines. Both in vivo tumoral growth and metastasis inhibition were evaluated by using a carcinoma model on Balb/c mice.

RESULTS

HM2 mix could suppress genetic and chromosome mutations induced by 4-nitro-o-phenylendiamine (4-NPD) and doxorubicin. Herbal mixture and single plant infusions showed cytotoxic effect against mammary, uterus, and brain tumoral cells without a selective action vs normal human cell line. HM2 mix was able to reduce mammary tumor mass on the Balb/c mice model and showed a significant reduction in the number of metastatic nodules in the lungs.

CONCLUSIONS

Our results suggest that the combinations of three Jarilla species from northwest Argentina would be a promising alternative to treat or slow down the development of chronic diseases, such as cancer.

HPLC–MS/MS profiling of wild-growing scentless chamomile

Scentless chamomile (Tripleurospermum inodorum = M. inodora) is a plant belonging to Anthemideae tribe of Asteraceae family, with phenotype similar to the common chamomile, a plant used in human consumption in the form of herbal tea infusion. In order to be able to understand possible health-promoting properties and adverse effects of the scentless chamomile's consumption, it is of essence to examine its chemical composition. The aim of the study was to perform phenolic profiling using high-performance liquid chromatography–tandem mass spectroscopy (HPLC–MS/MS), in comparison to the common chamomile. In the investigated extracts, qualitative and quantitative analyses enabled the identification of 66 compounds based on their retention times, mass (MS/MS) spectra, and analysis of their characteristic fragmentation patterns in MS/MS Product Ion Scan experiments. A new HPLC–MS/MS method for quantitation of common plant metabolites was hereby developed, enabling quantitation of 47 compounds. All examined M. inodora samples have relatively high combined phenolic and flavonoid contents (25.2–51.9 mg/g). Apigenin, apigenin-7-O-glucoside, luteolin, luteolin-7-O-glucoside, quinic acid, and 5-O-caffeoyl quinic acid were the compounds with highest concentration in both inodorous and common chamomile. The results obtained hereby represent the first and most detailed chemical profile of scentless chamomile so far.

A Comprehensive Network Pharmacology-Based Strategy to Investigate Multiple Mechanisms of HeChan Tablet on Lung Cancer

BACKGROUND

HeChan tablet (HCT) is a traditional Chinese medicine preparation extensively prescribed to treat lung cancer in China. However, the pharmacological mechanisms of HCT on lung cancer remain to be elucidated.

METHODS

A comprehensive network pharmacology-based strategy was conducted to explore underlying mechanisms of HCT on lung cancer. Putative targets and compounds of HCT were retrieved from TCMSP and BATMAN-TCM databases; related genes of lung cancer were retrieved from OMIM and DisGeNET databases; known therapeutic target genes of lung cancer were retrieved from TTD and DrugBank databases; PPI networks among target genes were constructed to filter hub genes by STRING. Furthermore, the pathway and GO enrichment analysis of hub genes was performed by clusterProfiler, and the clinical significance of hub genes was identified by The Cancer Genome Atlas.

RESULT

A total of 206 compounds and 2,433 target genes of HCT were obtained. 5,317 related genes of lung cancer and 77 known therapeutic target genes of lung cancer were identified. 507 unique target genes were identified among HCT-related genes of lung cancer and 34 unique target genes were identified among HCT-known therapeutic target genes of lung cancer. By PPI networks, 11 target genes AKT1, TP53, MAPK8, JUN, EGFR, TNF, INS, IL-6, MYC, VEGFA, and MAPK1 were identified as major hub genes. IL-6, JUN, EGFR, and MYC were shown to associate with the survival of lung cancer patients. Five compounds of HCT， quercetin, luteolin, kaempferol, beta-sitosterol, and baicalein were recognized as key compounds of HCT on lung cancer. The gene enrichment analysis implied that HCT probably benefitted patients with lung cancer by modulating the MAPK and PI3K-Akt pathways.

CONCLUSION

This study predicted pharmacological and molecular mechanisms of HCT against lung cancer and could pave the way for further experimental research and clinical application of HCT.

Xanthium strumarium´s xanthatins induces mitotic arrest and apoptosis in CT26WT colon carcinoma cells

BACKGROUND

Colorectal cancer is one of the most common malignancies worldwide and is associated with high mortality rates. We previously reported that Xanthium strumarium L. induces mitotic arrest in proliferating cells, a process mediated by xanthatins.

HYPOTHESIS/AIM

The aim of this work is to study if xanthatins, isolated from X. strumarium total extract, affect the proliferative capacity of CT26WT colon cancer cells and, in consequence, if tumor growth and proliferation of (lung) metastatic sites can also be arrested in vivo.

STUDY DESIGN

This study consisted of both in vitro and in vivo experiments involving the CT26WT cell line and a subcutaneous mouse model of colon cancer. In vitro cell cycle progression, in vivo tumoral growth and anti-metastatic activity were analyzed to investigate whether xanthatins of X. strumarium induce mitotic arrest in proliferating colorectal carcinoma.

RESULTS

Our in vitro results show that X. strumarium, mediated by xanthatins, induces G₂/M arrest and impair anaphase entrance. This leads to a significant induction of apoptotic and necrotic in CT26WT cells, demonstrating their significant anti-proliferative activity through interfering with the mitotic apparatus. Furthermore, our in vivoresults reveal that X. strumarium inhibits both tumor growth and metastasis progression.

CONCLUSION

X. strumarium antitumor activities are mainly mediated by xanthatins through inhibition of tumor growth and metastasis, inducing mitotic arrest and apoptosis in colon carcinoma cells. These findings further confirm the therapeutic potential of X. strumarium in colorectal cancer.

Myricetin suppresses breast cancer metastasis through down-regulating the activity of matrix metalloproteinase (MMP)-2/9

Tumour metastasis is the major cause of breast cancer mortality. Myricetin, a natural polyphenol, is found in teas, wines, and berries. The pharmacodynamic action and molecular mechanism of myricetin on breast cancer metastasis remain unknown. Here, we investigated the effect of myricetin on MDA-Mb-231Br cell viability, migration, invasion, and 4T1 mouse lung metastasis mouse models. MMP-2/9 protein expression and ST6GALNAC5 expression were analysed using western blot assays and quantitative real-time polymerase chain reaction, respectively. Cell migration and invasion were detected by wound-healing and Boyden transwell assays. The antimetastatic effect in vivo was evaluated by lung metastasis model. Myricetin significantly decreased the activities of MMP-2/9 and mRNA levels of ST6GALNAC5. In addition, the migration, invasion, and adhesion were effectively inhibited in a concentration-dependent manner. On the other hand, mice treated with myricetin exhibited smaller tumour nodules compared with the vehicle mice, with only 17.78 ± 15.41% after treatment with 50 mg/kg myricetin. In conclusion, myricetin could significantly block invasion of MDA-Mb-231Br cells through suppressing the protein expression of MMP-2/9 and the expression of ST6GALNAC5, as well as lung metastasis in a mouse model, which suggests that myricetin should be developed as a potential therapeutic candidate for breast cancer.

Combination of Luteolin and Solifenacin Improves Urinary Dysfunction Induced by Diabetic Cystopathy in Rats

Background

The purpose of the present study was to assess the effect of luteolin and solifenacin on diabetic cystopathy (DCP) and to investigate the mechanism of action. A novel link between the overexpression of c-Kit in the bladder and voiding dysfunction was identified in rats with DCP.

Material/Methods

A rat model of DCP was successfully established by intraperitoneal injection of streptozotocin and a diet high in glucose and lipids, and animals were treated with luteolin and solifenacin. The effect of luteolin and solifenacin on urinary dysfunction in DCP rats was investigated by assessing bladder pressure and performing a volume test. The protein levels of c-Kit, stem cell factor (SCF), p110, and phosphorylated p110 in the bladder were detected by Western blot analysis and immunohistochemical staining.

Results

In DCP rats, the protein levels of c-Kit, SCF and phosphorylated p110 in the bladder were significantly increased. However, oral treatment of DCP rats with luteolin combined with solifenacin resulted in effective improvement of overactive bladder and reduced the protein expression of c-Kit, SCF, and phosphorylated p110. Moreover, the effect of luteolin combined with solifenacin on maximum voiding pressure and residual urine volume was improved compared to that of luteolin alone.

Conclusions

Luteolin improved overactive bladder in DCP rats, which may be due to SCF/c-kit inhibition, as well as the downregulation of the phosphoinositide-3 kinase signaling pathway. Moreover, solifenacin enhanced the potential pharmacological effect of luteolin in the treatment of DCP.

Phytochemicals and PI3K Inhibitors in Cancer-An Insight

In today's world of modern medicine and novel therapies, cancer still remains to be one of the prime contributor to the death of people worldwide. The modern therapies improve condition of cancer patients and are effective in early stages of cancer but the advanced metastasized stage of cancer remains untreatable. Also most of the cancer therapies are expensive and are associated with adverse side effects. Thus, considering the current status of cancer treatment there is scope to search for efficient therapies which are cost-effective and are associated with lesser and milder side effects. Phytochemicals have been utilized for many decades to prevent and cure various ailments and current evidences indicate use of phytochemicals as an effective treatment for cancer. Hyperactivation of phosphoinositide 3-kinase (PI3K) signaling cascades is a common phenomenon in most types of cancers. Thus, natural substances targeting PI3K pathway can be of great therapeutic potential in the treatment of cancer patients. This chapter summarizes the updated research on plant-derived substances targeting PI3K pathway and the current status of their preclinical studies and clinical trials.

Potential anti-cancer activity of 7-O-pentyl quercetin: Efficient, membrane-targeted kinase inhibition and pro-oxidant effect

Quercetin is a redox-active plant-derived flavonoid with potential anticancer effects, stemming largely from its interaction with a number of proteins, and in particular from inhibition of pro-life kinases. To improve efficacy, we reasoned that a local increase in concentration of the compound at the level of cell membranes would result in a more efficient interaction with membrane-associated signaling kinases. We report here the synthesis of all five isomeric quercetin derivatives in which an n-pentyl group was linked via an ether bond to each hydroxyl of the flavonoid kernel. This strategy proved effective in directing quercetin to cellular membranes, and revealed a remarkable dependence of the derivatives' bioactivity on the specific site of functionalization. The isomer bearing the pentyl group in position 7, Q-7P, turned out to be the most effective and promising derivative, selectively inducing apoptosis in tumoral and fast-growing cells, while sparing slow-growing, non-tumoral ones. Cytotoxicity for tumoral cells was strongly enhanced compared to quercetin itself. Q-7P induced massive ROS production, which however accounted only partially for cell death. Alterations in the levels of various signaling phospho-proteins were observed in a proteomics screen. An important contribution seems to come from inhibition of the PI3K/Akt pathway. This work opens new perspectives in developing membrane-associating, polyphenol-based anticancer agents.

Reducing Interstitial Fluid Pressure and Inhibiting Pulmonary Metastasis of Breast Cancer by Gelatin Modified Cationic Lipid Nanoparticles

Interstitial fluid pressure (IFP) in tumor is much higher than that in normal tissue, and it constitutes a great obstacle for the delivery of antitumor drugs, thus becoming a potential target for cancer therapy. In this study, cationic nanostructured lipid carriers (NLCs) were modified by low molecular weight gelatin to achieve the desirable reduction of tumor IFP and improve the drug delivery. In this way, the chemotherapy of formulations on tumor proliferation and pulmonary metastasis was further improved. The nanoparticles were used to load three drugs, docetaxel (DTX), quercetin (Qu), and imatinib (IMA), with high encapsulation efficiency of 89.54%, 96.45%, and 60.13%, respectively. GNP-DTX/Qu/IMA nanoparticles exhibited an enzyme-sensitive drug release behavior, and the release rate could be mediated by matrix metalloproteinases (MMP-9). Cellular uptake and MTT assays showed that the obtained GNP-DTX/Qu/IMA could be internalized into human breast 4T1 cells effectively and exhibited the strongest cytotoxicity. Moreover, GNP-DTX/Qu/IMA demonstrated obvious advantages in inducing apoptosis and mediating the expression of apoptosis-related proteins (Caspase 3, Caspase 9, and bcl-2). In the wound-healing assay, GNP-DTX/Qu/IMA exhibited evidently inhibition of cell migration. The benefits of tumor IFP reduction induced by GNP-DTX/Qu/IMA were further proved after a continuous administration to 4T1 tumor-bearing mice. Finally, in the in vivo antitumor assays, GNP-DTX/Qu/IMA displayed stronger antitumor efficiency as well as suppression on pulmonary metastasis. In conclusion, the GNP-DTX/Qu/IMA system might be a promising strategy for metastatic breast cancer treatment.

Assessing the anticancer effects associated with food products and/or nutraceuticals using in vitro and in vivo preclinical development-related pharmacological tests

This review is part of a special issue entitled "Role of dietary pattern, foods, nutrients and nutraceuticals in supporting cancer prevention and treatment" and describes a pharmacological strategy to determine the potential contribution of food-related components as anticancer agents against established cancer. Therefore, this review does not relate to chemoprevention, which is analysed in several other reviews in the current special issue, but rather focuses on the following: i) the biological events that currently represent barriers against the treatment of certain types of cancers, primarily metastatic cancers; ii) the in vitro and in vivo pharmacological pre-clinical tests that can be used to analyse the potential anticancer effects of food-related components; and iii) several examples of food-related components with anticancer effects. This review does not represent a catalogue-based listing of food-related components with more or less anticancer activity. By contrast, this review proposes an original pharmacological strategy that researchers can use to analyse the potential anticancer activity of any food-related component-e.g., by considering the crucial characteristics of cancer biological aggressiveness. This review also highlights that cancer patients undergoing chemotherapy should restrict the use of "food complements" without supervision by a medical nutritionist. By contrast, an equilibrated diet that includes the food-related components listed herein would be beneficial for cancer patients who are not undergoing chemotherapy.

Luteolin inhibits lung metastasis, cell migration, and viability of triple-negative breast cancer cells

Most breast cancer-related deaths from triple-negative breast cancer (TNBC) occur following metastasis of cancer cells and development of tumors at secondary sites. Because TNBCs lack the three receptors targeted by current chemotherapeutic regimens, they are typically treated with extremely aggressive and highly toxic non-targeted treatment strategies. Women with TNBC frequently develop metastatic lesions originating from drug-resistant residual cells and have poor prognosis. For this reason, novel therapeutic strategies that are safer and more effective are sought. Luteolin (LU) is a naturally occurring, non-toxic plant compound that has proven effective against several types of cancer. With this in mind, we conducted in vivo and in vitro studies to determine whether LU might suppress metastasis of TNBC. In an in vivo mouse metastasis model, LU suppressed metastasis of human MDA-MB-435 and MDA-MB-231 (4175) LM2 TNBC cells to the lungs. In in vitro assays, LU inhibited cell migration and viability of MDA-MB-435 and MDA-MB-231 (4175) LM2 cells. Further, LU induced apoptosis in MDA-MB-231 (4175) LM2 cells. Relatively low levels (10 µM) of LU significantly inhibited vascular endothelial growth factor (VEGF) secretion in MDA-MB-231 (4175) LM2 cells, suggesting that it has the ability to suppress a potent angiogenic and cell survival factor. In addition, migration of MDA-MB-231 (4175) LM2 cells was inhibited upon exposure to an antibody against the VEGF receptor, KDR, but not by exposure to a VEGF₁₆₅ antibody. Collectively, these data suggest that the anti-metastatic properties of LU may, in part, be due to its ability to block VEGF production and KDR-mediated activity, thereby inhibiting tumor cell migration. These studies suggest that LU deserves further investigation as a potential treatment option for women with TNBC.

Molecular targets of luteolin in cancer

Many food-derived phytochemical compounds and their derivatives represent a cornucopia of new anticancer compounds. Despite extensive study of luteolin, the literature has no information on the exact mechanisms or molecular targets through which it deters cancer progression. This review discusses existing data on luteolin's anticancer activities and then offers possible explanations for and molecular targets of its cancer-preventive action. Luteolin prevents tumor development largely by inactivating several signals and transcription pathways essential for cancer cells. This review also offers insights into the molecular mechanisms and targets through which luteolin either prevents cancer or mediates cancer cell death.

Luteolin ameliorates dextran sulfate sodium-induced colitis in mice possibly through activation of the Nrf2 signaling pathway

BACKGROUND

Luteolin has a reputation for being a safe and effective natural antioxidant that has strong radical scavenging and cell protective properties. The role of oxidative stress in inflammatory bowel disease (IBD) has been well established and is increasingly highlighted. Thus, we studied the protective effect of luteolin administration in a mouse model of experimental colitis.

METHODS

Experimental acute colitis was induced by administering 3% dextran sulfate sodium (DSS) in the drinking water of mice for 7days. The disease activity index (DAI); colon length; histological assessment; mRNA levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), heme oxygenase-1 (HO-1), and NADP(H): quinone oxidoreductase 1 (NQO-1); protein expression of Nrf2 and inducible nitric oxide synthase (iNOS); colon malondialdehyde (MDA) levels; and the activity levels of colonic superoxide dismutase (SOD) and catalase (CAT) were examined.

RESULTS

Luteolin (20 and 50mg/kg) significantly attenuated the DAI, colon shortening and histological damage. In addition, luteolin administration effectively decreased the expression of inflammatory mediators, such as iNOS, TNF-α and IL-6. Luteolin also decreased the colonic content of MDA. The activities of colonic SOD and CAT and the levels of Nrf2 and its downstream targets, HO-1 and NQO1, were elevated by luteolin treatment.

CONCLUSION

These observations indicate that luteolin may suppress experimental colitis through the Nrf2 signaling pathway.

Comparative study of anti-angiogenic activities of luteolin, lectin and lupeol biomolecules

BACKGROUND

Angiogenesis is a hallmark feature in the initiation, progression and growth of tumour. There are various factors for promotion of angiogenesis on one hand and on the other hand, biomolecules have been reported to inhibit cancer through anti-angiogenesis mechanism. Biomolecules, for instance, luteolin, lectin and lupeol are known to suppress cancer. This study aims to compare and evaluate the biomolecule(s) like luteolin, lupeol and lectin on CAM assay and HT-29 cell culture to understand the efficacy of these drugs.

METHOD

The biomolecules have been administered on CAM assay, HT-29 cell culture, cell migration assay. Furthermore, bioinformatics analysis of the identified targets of these biomolecules have been performed.

RESULT

Luteolin has been found to be better in inhibiting angiogenesis on CAM assay in comparison to lupeol and lectin. In line with this study when biomolecules was administered on cell migration assay via scratch assay method. We provided evidence that Luteolin was again found to be better in inhibiting HT-29 cell migration. In order to identify the target sites of luteolin for inhibition, we used software analysis for identifying the best molecular targets of luteolin. Using software analysis best target protein molecule of these biomolecules have been identified. VEGF was found to be one of the target of luteolin. Studies have found several critical point mutation in VEGF A, B and C. Hence docking analysis of all biomolecules with VEGFR have been performed. Multiple allignment result have shown that the receptors are conserved at the docking site.

CONCLUSION

Therefore, it can be concluded that luteolin is not only comparatively better in inhibiting blood vessel in CAM assay, HT-29 cell proliferation and cell migration assay rather the domain of VEGFR is conserved to be targeted by luteolin, lupeol and lectin.

Luteolin 8-C-β-fucopyranoside downregulates IL-6 expression by inhibiting MAPKs and the NF-κB signaling pathway in human monocytic cells

Numerous studies have been suggested that derivatives can improve the effects of original substances. Therefore, we made luteolin derivative luteolin 8-C-β-fucopyranoside (LU8C-FP) for better anti-inflammatory and anti-cancer effects. In a previous study, we demonstrated that LU8C-FP inhibits invasion of human breast cancer cells via suppression of matrix metalloproteinase 9 and IL-8, which play major roles in tumor progression and cancer cell invasion. Various stimuli trigger inflammatory responses by inducing pro-inflammatory cytokines and chemokines in THP-1 cells. IL-6 induces inflammation via inducing various cytokines and appears to be a potential mediator of inflammatory diseases. Here, we investigated the precise mechanism by which LU8C-FP inhibited phorbol 12-myristate 13-acetate-induced IL-6 mRNA and protein expression. We showed LU8C-FP downregulated IL-6 expression by inhibiting mitogen-activated protein kinases and the nuclear factor-kappaB signaling pathway in human monocytic cells. Furthermore, LU8C-FP exerts less cytotoxicity than luteolin and also it has specific inhibitory effect on IL-6 expression. However, luteolin has a variety of inhibitory effects on pro-inflammatory cytokines and chemokines. Our in vitro studies may provide valuable information leading to the use of LU8C-FP to treat inflammatory diseases caused by IL-6.

Natural inhibitors of PI3K/AKT signaling in breast cancer: emphasis on newly-discovered molecular mechanisms of action

Epidermal growth factor receptor (EGFR) plays a critical role in the initiation and progression of a variety of human cancers, including breast cancer. An important signaling pathway downstream of EGFR is the PI3K/AKt pathway, which regulates cellular processes as diverse as cell growth, survival, proliferation and migration. Deregulated activity of this pathway may lead to uncontrolled cell growth, survival, migration and invasion, contributing to tumor formation. In this review, we evaluate natural compounds that, in vitro (breast cancer cell lines) and/or in vivo (animal model, clinical) studies, suppress breast cancer cells or tumors mainly by suppressing the PI3K/AKT signaling pathway. The effect of these compounds on cell cycle arrest, inhibition of cell migration and invasion, tumor angiogenesis and metastasis in breast cancer are discussed.

Luteolin inhibits hyperglycemia-induced proinflammatory cytokine production and its epigenetic mechanism in human monocytes

Hyperglycemia is a key feature in diabetes. Hyperglycemia has been implicated as a major contributor to several complications of diabetes. High glucose levels induce the release of proinflammatory cytokines. Luteolin is a flavone isolated from celery, green pepper, perilla leaf, and chamomile tea. Luteolin has been reported to possess antimutagenic, antitumorigenic, antioxidant, and anti-inflammatory properties. In this study, we investigated the effects of luteolin on proinflammatory cytokine secretion and its underlying epigenetic regulation in high-glucose-induced human monocytes. Human monocytic (THP-1) cells were cultured under controlled (14.5 mM mannitol), normoglycemic (NG, 5.5 mM glucose), or hyperglycemic (HG, 20 mM glucose) conditions, in the absence or presence of luteolin. Luteolin (3-10 μM) was added for 48 h. While hyperglycemic conditions significantly induced histone acetylation, NF-κB activation, and proinflammatory cytokine (IL-6 and TNF-α) release from THP-1 cells, luteolin suppressed NF-κB activity and cytokine release. Luteolin also significantly reduced CREB-binding protein/p300 (CBP/p300) gene expression, as well as the levels of acetylation and histone acetyltransferase (HAT) activity of the CBP/p300 protein, which is a known NF-κB coactivator. These results suggest that luteolin inhibits HG-induced cytokine production in monocytes, through epigenetic changes involving NF-κB. We therefore suggest that luteolin may be a potential candidate for the treatment and prevention of diabetes and its complications.

Luteolin 8-C-β-fucopyranoside inhibits invasion and suppresses TPA-induced MMP-9 and IL-8 via ERK/AP-1 and ERK/NF-κB signaling in MCF-7 breast cancer cells

Matrix metalloproteinase 9 (MMP-9) and interleukin-8 (IL-8) play major roles in tumor progression and invasion of breast cancer cells. The present study was undertaken to investigate the inhibitory mechanism of cell invasion by luteolin 8-C-β-fucopyranoside (named as LU8C-FP), a C-glycosylflavone, in human breast cancer cells. We investigated whether LU8C-FP would inhibit MMP-9 activation and IL-8 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated MCF-7 breast cancer cells. LU8C-FP suppressed TPA-induced MMP-9 and IL-8 secretion and mRNA expression via inhibition of the MAPK signaling pathway and down-regulation of nuclear AP-1 and NF-κB. TPA-induced phosphorylation of ERK 1/2 was suppressed by LU8C-FP, whereas JNK and p38 MAPK phosphorylation were unaffected. In addition, LU8C-FP blocked the ERK 1/2 pathways following expression of MMP-9 and IL-8. These results suggest LU8C-FP may function to suppress invasion of breast cancer cells through the ERK/AP-1 and ERK/NF-κB signaling cascades.

The P110 subunit of PI3-K is a therapeutic target of acacetin in skin cancer

The identification of primary molecular targets of cancer-preventive phytochemicals is essential for a comprehensive understanding of their mechanism of action. In the present study, we investigated the chemopreventive effects and molecular targets of acacetin, a flavonoid found in Robinia p seudoacacia, also known as black locust. Acacetin treatment significantly suppressed epidermal growth factor (EGF)-induced cell transformation. Immunoblot analysis revealed that acacetin attenuated EGF-induced phosphorylation of Akt and p70(S6K), which are downstream effectors of phosphatidylinositol 3-kinase (PI3-K). An immunoprecipitation kinase assay of PI3-K and pull-down assay results demonstrated that acacetin substantially inhibits PI3-K activity by direct physical binding. Acacetin exhibited stronger inhibitory effects against anchorage-dependent and -independent cell growth in cells expressing higher PI3-K activity compared with those exhibiting relatively low PI3-K activity. Binding assay data combined with computational modeling suggest that acacetin binds in an adenosine triphosphate (ATP)-competitive manner with the p110α subunit of PI3-K and interacts with Val828, Glu826, Asp911, Trp760, Ile777, Ile825, Tyr813, Ile910 and Met900 residues. Acacetin was also found to significantly reduce SK-MEL-28 tumor growth and Akt phosphorylation in vivo. Taken together, these results indicate that acacetin is an ATP-competitive PI3-K inhibitor and a promising agent for melanoma chemoprevention.