Dieckol from Ecklonia cava Regulates Invasion of Human Fibrosarcoma Cells and Modulates MMP-2 and MMP-9 Expression via NF-κB Pathway

PATTERN OF MMP2 AND MMP9 EXPRESSION DEPENDS ON BREAST CANCER PATIENTS' AGE

BACKGROUND

Despite the large number of studies devoted to the study of the features of tumor microenvironment in breast cancer (BCa), presently there is no consensus on the features of MMP-2 and MMP-9 expression in the tumor tissue of BCa patients depending on the age. The aim of the study was to investigate the relationship between MMP-2 and -9 expression at the protein and mRNA levels in BCa tissues and the clinical and pathological features of BCapatientsin different age groups.

MATERIALS AND METHODS

The expression level of MMP-2 and -9in the BCa tissue of patients of two age groups (< 45 years and > 45 years) was studied using the bioinformatics method (UALCAN database), immunohistochemical method, and real-time PCR.

RESULTS

It was established that a characteristic feature of BCa in young patients is the low level of MMP2 mRNA against the background of increased expression of this gelatinase at the protein level, as well as decreased expression of MMP9 at both the mRNA and protein levels. When analyzing the correlation of the gelatinase expression indices in BCa tissue of young patients, depending on the clinical and pathological features, a significantly lower level of MMP-2 expression was recorded in BCa cases of stage II compared to the indices of stage I cases. High expression of MMP-2 and -9 was recorded in BCa tissue in node-positive cases and the basal molecular BCa subtype.

CONCLUSIONS

The identified relationship between the expression of the studied gelatinases and such indices of BCa malignancy as its stage, positive regional lymph node status, and the molecular BCa subtype in young patients indicates the need for further research of the features of the tumor microenvironment to predict the cancer aggressiveness.

Dieckol Isolated from Eisenia bicyclis Ameliorates Wrinkling and Improves Skin Hydration via MAPK/AP-1 and TGF-β/Smad Signaling Pathways in UVB-Irradiated Hairless Mice

Repetitive exposure to ultraviolet B (UVB) is one of the main causes of skin photoaging. We previously reported that dieckol isolated from Eisenia bicyclis extract has potential anti-photoaging effects in UVB-irradiated Hs68 cells. Here, we aimed to evaluate the anti-photoaging activity of dieckol in a UVB-irradiated hairless mouse model. In this study, hairless mice were exposed to UVB for eight weeks. At the same time, dieckol at two doses (5 or 10 mg/kg) was administered orally three times a week. We found that dieckol suppressed UVB-induced collagen degradation and matrix metalloproteinases (MMPs)-1, -3, and -9 expression by regulating transforming growth factor beta (TGF-β)/Smad2/3 and mitogen-activated protein kinases (MAPKs)/activator protein-1 (AP-1) signaling. In addition, dieckol rescued the production of hyaluronic acid (HA) and effectively restored the mRNA expression of hyaluronan synthase (HAS)-1/-2 and hyaluronidase (HYAL)-1/-2 in UVB-irradiated hairless mice. We observed a significant reduction in transepidermal water loss (TEWL), epidermal/dermal thickness, and wrinkle formation in hairless mice administered dieckol. Based on these results, we suggest that dieckol, due to its anti-photoaging role, may be used as a nutricosmetic ingredient for improving skin health.

Regioselective Synthesis of 6-O-Acetyl Dieckol and Its Selective Cytotoxicity against Non-Small-Cell Lung Cancer Cells

Dieckol, a phlorotannin from Ecklonia cava, has shown potential for use as an anticancer agent that selectively kills cancer cells. However, it is necessary to amplify its potency without damaging its inherent safety in order to develop it as a competitive chemotherapeutic. Here, we explored the controlled O-acylations of dieckol. Acyl groups could be consistently introduced to the 6-O position of dieckol with a high regioselectivity, which was confirmed by NOESY, HMBC and HSQC spectroscopies. In cytotoxicity studies on the newly synthesized 6-O-acetyl, 6-O-benzoyl dieckols and previously synthesized 6-O-alkyl dieckols against A549 vs. normal cells, all of the derivatives showed low cytotoxicity in normal cells with an IC50 of 481-719 μM, and highly structure-dependent cytotoxicity in A549 cells with an IC50 of 7.02 (acetyl)-842.26 (benzyl) μM. The selectivity index also showed a large structure dependency in the range of 0.67 (benzyl)-68.58 (acetyl). An analysis of the structure-activity relationship indicated that the activity was dramatically reduced in the presence of a benzene ring and was highly increased in the presence of small polar substituents. Conclusions: Controlled mono-O-modifications of dieckol could be a powerful tool to enhance the anticancer activity of dieckol, thus contributing to the development strategy for dieckol-based chemotherapeutics.

Call the Eckols: Present and Future Potential Cancer Therapies

In recent years, an increased interest in marine macroalgae bioactive compounds has been recorded due to their benefits to human health and welfare. Several of their bioactivities have been demonstrated, such as anti-inflammatory, antioxidant, anticarcinogenic, antibacterial and antiviral behavior. However, there still lacks a clear definition regarding how these compounds exert their bioactive properties. Of all the bioactive compounds derived from marine macroalgae, attention has been focused on phenolic compounds, specifically in phlorotannins, due to their potential for biomedical applications. Phlorotannins are a diverse and wide group of phenolic compounds, with several structural variations based on the monomer phloroglucinol. Among the diverse phlorotannin structures, the eckol-family of phlorotannins demonstrates remarkable bioactivity, notably their anti-tumoral properties. However, the molecular mechanisms by which this activity is achieved remain elusive and sparse. This review focuses on the described molecular mechanisms of anti-tumoral effects by the eckol family of compounds and the future prospects of these molecules for potential application in oncology therapies.

Anticancer effects of marine compounds blocking the nuclear factor kappa B signaling pathway

The abnormal expression of nuclear factor kappa B (NF-κB) target genes is closely related to the occurrence, metastasis, and invasion of tumor cells and is an inhibitor of their apoptosis. In recent years, the unique biodiversity in the marine environment has aroused great interest. Many studies indicate that some marine compounds exert anticancer effects on most common human tumors by modulating the NF-κB signaling pathway. In this study, 26 marine compounds that reduce cancer cell survival by suppressing the NF-κB signaling pathway were reviewed. They were derived from a wide range of sources, including sponges, fungi, algae and their derivatives or metabolites. These marine compounds exert antitumor effects through the canonical, noncanonical and atypical NF-κB signaling pathways; however, most of their anticancer targets and mechanisms remain unclear, and more research is needed in the future. Our article provides comprehensive information for researchers investigating the bioactivities of marine compounds and developing marine-derived anticancer drugs.

Anticancer Activities of Marine-Derived Phenolic Compounds and Their Derivatives

Since the middle of the last century, marine organisms have been identified as producers of chemically and biologically diverse secondary metabolites which have exerted various biological activities including anticancer, anti-inflammatory, antioxidant, antimicrobial, antifouling and others. This review primarily focuses on the marine phenolic compounds and their derivatives with potent anticancer activity, isolated and/or modified in the last decade. Reports on the elucidation of their structures as well as biosynthetic studies and total synthesis are also covered. Presented phenolic compounds inhibited cancer cells proliferation or migration, at sub-micromolar or nanomolar concentrations (lamellarins D (37), M (38), K (39), aspergiolide B (41), fradimycin B (62), makulavamine J (66), mayamycin (69), N-acetyl-N-demethylmayamycin (70) or norhierridin B (75)). In addition, they exhibited anticancer properties by a diverse biological mechanism including induction of apoptosis or inhibition of cell migration and invasive potential. Finally, phlorotannins 1–7 and bromophenols 12–29 represent the most researched phenolic compounds, of which the former are recognized as protective agents against UVB or gamma radiation-induced skin damages. Finally, phenolic metabolites were assorted into six main classes: phlorotannins, bromophenols, flavonoids, coumarins, terpenophenolics, quinones and hydroquinones. The derivatives that could not be attributed to any of the above-mentioned classes were grouped in a separate class named miscellaneous compounds.

Dieckol: a brown algal phlorotannin with biological potential

Dieckol [C36H22O18], is a naturally occurring phlorotannin found in some brown algal species. Dieckol is gaining more attention in the scientific community for its potential biological activities. It has been exhibited a broad spectrum of therapeutic functions including anti-bacterial, anti-cancer, anti-oxidant, anti-aging, anti-diabetic, neuroprotective, and other medicinal applications. Distinct emphasis has been given to extraction, purification, and biomedical applications of dieckol. This critical review comprises of in vitro, in vivo, and in silico biological properties of dieckol. An attempt has been made to evaluate the effectiveness, therapeutical application, and mechanism of dieckol against various diseases. The pharmacological significance, current status and the dosage of multifunctional dieckol and its mechanisms have been discussed in this review. Dieckol plays an important role in apoptosis induction via inhibiting the PI3K, AKT, mTOR and FAK signaling molecules. Dieckol remarkably inhibited the lipid accumulation in high fat diet induced animal models. Dieckol, a multifaceted compound will be beneficial in attenuating the action of various diseases and it could be a potential pharmaceutical and nutraceutical compound. Therefore, the combined effects of dieckol with existing drugs and natural compounds will be studied in future to optimize its benefits. Besides limited information on the toxicological action and dosage administration of dieckol on the human was reported to date. Overall, dieckol is a prospective health-promoting compound for the development of a novel drug against numerous diseases.

Antioxidant and Signal-Modulating Effects of Brown Seaweed-Derived Compounds against Oxidative Stress-Associated Pathology

The biological and therapeutic properties of seaweeds have already been well known. Several studies showed that among the various natural marine sources of antioxidants, seaweeds have become a potential source of antioxidants because of their bioactive compounds. Most of the metabolic diseases are caused by oxidative stress. It is very well known that antioxidants have a pivotal role in the treatment of those diseases. Recent researches have revealed the potential activity of seaweeds as complementary medicine, which have therapeutic properties for health and disease management. Among the seaweeds, brown seaweeds (Phaeophyta) and their derived bioactive substances showed excellent antioxidant properties than other seaweeds. This review focuses on brown seaweeds and their derived major bioactive compounds such as sulfated polysaccharide, polyphenol, carotenoid, and sterol antioxidant effects and molecular mechanisms in the case of the oxidative stress-originated disease. Antioxidants have a potential role in the modification of stress-induced signaling pathways along with the activation of the oxidative defensive pathways. This review would help to provide the basis for further studies to researchers on the potential antioxidant role in the field of medical health care and future drug development.

Phlorotannins: From isolation and structural characterization, to the evaluation of their antidiabetic and anticancer potential

Phlorotannins are phenolic characteristic compounds of brown seaweeds that are only constituted by phloroglucinol (1,3,5-trihydroxybenzene). They are chain- and net-like structures of diverse molecular weights and have been widely identified in Ecklonia, Eisenia, and Ishige species. Since the time they were discovered in the '70 s, phlorotannins have been suggested as a main factor responsible for the antimicrobial activities attributed to algae extracts. Currently, cumulative in vitro and in vivo research evidence the diverse bioactivities of phlorotannin extracts -such as antidiabetic, anticancer, and antibacterial- pointing out their potential pharmacological and food applications. However, metabolomic studies and clinical trials are scarce, and thus many phlorotannins health-beneficial effects in humans are not yet confirmed. This article reviews recent studies assessing the antidiabetic and anticancer activities of phlorotannins. Particularly, their potential to prevent and control the progression of these non-communicable diseases is discussed, considering in vitro and animal studies, as well as clinical interventions. In contrast to other approaches, we only included investigations with isolated phlorotannins or phlorotannin-rich extracts. Thus, phlorotannin extraction, purification and characterization procedures are briefly addressed. Overall, although considerable research showing the antidiabetic and anticancer potential of phlorotannins is now available, further clinical trials are still necessary to conclusively demonstrate the efficacy of these compounds as adjuvants for diabetes and cancer prevention or treatment.

Comparative Studies of Different Extracts from Eucommia ulmoides Oliv. against Rheumatoid Arthritis in CIA Rats

To compare efficacy of different extracts from Eucommia ulmoides Oliv. with both immune inflammation and joint destruction in collagen induced arthritis (CIA) rat model. Rats were divided into normal group (Nor), control group (CIA), TG group (treated with tripterygium glycoside), E70 group (treated with 70% ethanol extract from Eucommia ulmoides Oliv.), EA group (treated with ethyl acetate fraction from E70), and EN group (treated with n-butyl alcohol fraction from E70). All extracts from Eucommia ulmoides Oliv. could significantly inhibit ankle swelling, pathological manifestations, and cytokine levels in serum and spleen, by using foot volume measurement, H&E staining, ELISA, and RT-QPCR methods, respectively. All extracts could significantly inhibit rough joint surface and marginal osteophytes, improve RANKL/OPG ratio, and decrease MMP-9 expression, by using micro-CT and immunohistochemical staining. The activation of IKK/NF-κB signaling pathway was also inhibited by all extracts. In addition, ethyl acetate fraction from E70 presented better effect on RANKL/OPG system. This study identified effective extracts from Eucommia ulmoides Oliv. relieving immune inflammation and maintaining structural integrity of joints in CIA rats.

Allicin inhibits the invasion of lung adenocarcinoma cells by altering tissue inhibitor of metalloproteinase/matrix metalloproteinase balance via reducing the activity of phosphoinositide 3-kinase/AKT signaling

Allicin, the main active principle associated with Allium sativum chemistry, has various antitumor activities. However, to the best of our knowledge, there is no available information to address the anti-invasive effect and associated mechanism in lung adenocarcinoma. In the present study, cell viability assay, cell adhesion assay, western blot analysis, Transwell migration and invasion assays and reverse transcription-quantitative polymerase chain reaction were performed. Allicin was identified to inhibit the adhesion, invasion and migration of lung adenocarcinoma cells in a dose-dependent manner, accompanied by decreasing mRNA and protein levels of matrix metalloproteinase (MMP)-2 and MMP-9. Conversely, the mRNA and protein levels of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were increased in a dose-dependent manner. Furthermore, it was revealed that allicin treatment significantly suppressed the phosphorylation of AKT (P<0.05), but not the total protein expression of AKT. Combined treatment with LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K)/AKT signaling, and allicin led to the synergistic reduction of MMP-2 and MMP-9 expression, followed by an increase in TIMP-1 and TIMP-2 expression. The invasive capabilities of lung adenocarcinoma cells were also suppressed. However, insulin-like growth factor-1 (an activator of PI3K/AKT signaling) reversed the effects of allicin on cell invasion and expression of MMP-2, MMP-9, TIMP-1 and TIMP-2. The present study concluded that allicin may inhibit invasion of lung adenocarcinoma cells by altering TIMP/MMP balance, via reducing the activity of the PI3K/AKT signaling pathway. This indicated that allicin may be recognized as an anti-invasive agent for lung adenocarcinoma treatment.

Protective Effect of Brown Alga Phlorotannins against Hyper-inflammatory Responses in Lipopolysaccharide-Induced Sepsis Models

Brown algae have been recognized as a food ingredient and health food supplement in Japan and Korea, and phlorotannins are unique marine phenol compounds produced exclusively by brown algae. Sepsis is a whole-body inflammatory condition with a mortality rate of 30-40%. Here, we investigated the effects of a phlorotannin-rich extract of the edible brown alga Ecklonia cava against hyper-inflammatory response in LPS-induced septic shock mouse model. E. cava extract significantly increased the survival rate and attenuated liver and kidney damage in the mice. In addition, E. cava attenuated serum levels of NO, PGE2, and HMGB-1. In macrophages, treatment with E. cava extract down-regulated iNOS, COX-2, TNF-α, IL-6, and HMGB-1. In addition, E. cava suppressed the NIK/TAK1/IKK/IκB/NFκB pathway. Moreover, E. cava increased Nrf2 and HO-1 expression. HO-1 knockdown using siRNA restored the extract-suppressed NO and PGE2 production. Dieckol, a major compound in the extract, reduced mortality, tissue toxicity, and serum levels of the inflammatory factors in septic mice. These data suggest that brown algae phlorotannins suppress septic shock through negative regulation of pro-inflammatory factors via the NIK/TAK1/IKK/IκB/NFκB and Nrf2/HO-1 pathways.

Fucofuroeckol-A fromEisenia bicyclisInhibits Inflammation in Lipopolysaccharide-Induced Mouse Macrophages via Downregulation of the MAPK/NF-κB Signaling Pathway

Fucofuroeckol-A (FF) isolated from an edible perennial brown seaweedEisenia bicycliswas shown to be potent anti-inflammatory agents. FF suppressed the production of nitric oxide (NO) and prostaglandin E2(PGE2) and the expression of inducible nitric oxide synthase and cyclooxygenase-2 dose dependently in lipopolysaccharide- (LPS-) induced RAW 264.7 mouse macrophages. An enzyme-linked immunosorbent assay and cytometric bead array assay demonstrated that FF significantly reduced the production of proinflammatory cytokines, such as interleukin-6 and tumor necrosis factor-α, and that of the monocyte chemoattractant protein-1. Moreover, FF reduced the activation of nuclear factorκB (NF-κB) and mitogen-activated protein kinases (MAPKs). These results strongly suggest that the inhibitory effects of fucofuroeckol-A fromE. bicyclison LPS-induced NO and PGE2production might be due to the suppression of the NF-κB and MAPK signaling pathway.

Brown algae phlorotannins enhance the tumoricidal effect of cisplatin and ameliorate cisplatin nephrotoxicity

OBJECTIVE

The clinical application of cisplatin is limited due to its drug resistance and side effects. We investigated the effect of a phlorotannin-rich extract from the edible brown alga Ecklonia cava (PREC) and its major phlorotannin (dieckol) on cisplatin responsiveness and side effects.

METHODS

The A2780 and SKOV3 ovarian cancer cell lines and the SKOV3-bearing mouse model were used. The MTT assay was applied to assess cell viability, and the annexin V assay was employed for apoptosis analysis. Reactive oxygen species (ROS) production and protein expression were assessed by H2DCFDA staining and Western blotting, respectively.

RESULTS

We found that PREC enhanced the tumor growth-inhibitory effect of cisplatin and diminished cisplatin-induced nephrotoxicity and weight loss in SKOV3-bearing mice. PREC augmented cisplatin-induced apoptosis by activating caspases in SKOV3 and A2780 ovarian cancer cells. In addition, a combination of PREC and cisplatin-induced ovarian cancer cell apoptosis by downregulating the Akt and NFκB pathways. We further demonstrated that PREC increased intracellular ROS and that antioxidants significantly attenuated Akt-NFκB activation and apoptosis in ovarian cancer cells. In contrast, PREC inhibited cisplatin-induced ROS production and cell death in normal HEK293 kidney cells. Dieckol, a major compound in PREC, significantly enhanced the inhibition of tumor growth by cisplatin with less weight loss and kidney damage in a mouse model.

CONCLUSION

These data suggest that brown algae phlorotannins may improve the efficacy of platinum drugs for ovarian cancer by enhancing cancer cell apoptosis via the ROS/Akt/NFκB pathway and reduce nephrotoxicity by protecting against normal kidney cell damage.

Dieckol, isolated from the edible brown algae Ecklonia cava, induces apoptosis of ovarian cancer cells and inhibits tumor xenograft growth

PURPOSE

Ecklonia cava is an abundant brown alga and has been reported to possess various bioactive compounds having anti-inflammatory effect. However, the anticancer effects of dieckol, a major active compound in E. cava, are poorly understood. In the present study, we investigated the anti-tumor activity of dieckol and its molecular mechanism in ovarian cancer cells and in a xenograft mouse model .

METHODS

MTT assay, PI staining, and PI and Annexin double staining were performed to study cell cytotoxicity, cell cycle distribution, and apoptosis. We also investigated reactive oxygen species (ROS) production and protein expression using flow cytometry and Western blot analysis, respectively. Anti-tumor effects of dieckol were evaluated in SKOV3 tumor xenograft model.

RESULTS

We found that the E. cava extract and its phlorotannins have cytotoxic effects on A2780 and SKOV3 ovarian cancer cells. Dieckol induced the apoptosis of SKOV3 cells and suppressed tumor growth without any significant adverse effect in the SKOV3-bearing mouse model. Dieckol triggered the activation of caspase-8, caspase-9, and caspase-3, and pretreatment with caspase inhibitors neutralized the pro-apoptotic activity of dieckol. Furthermore, treatment with dieckol caused mitochondrial dysfunction and suppressed the levels of anti-apoptotic proteins. We further demonstrated that dieckol induced an increase in intracellular ROS, and the antioxidant N-acetyl-L-cysteine (NAC) significantly reversed the caspase activation, cytochrome c release, Bcl-2 downregulation, and apoptosis that were caused by dieckol. Moreover, dieckol inhibited the activity of AKT and p38, and overexpression of AKT and p38, at least in part, reversed dieckol-induced apoptosis in SKOV3 cells.

CONCLUSION

These data suggest that dieckol suppresses ovarian cancer cell growth by inducing caspase-dependent apoptosis via ROS production and the regulation of AKT and p38 signaling.

Hemeoxygenase 1 partly mediates the anti-inflammatory effect of dieckol in lipopolysaccharide stimulated murine macrophages

Eisenia bicyclis is edible brown algae recognized as a rich source of bioactive derivatives mainly phlorotannins reported for their anti-oxidant properties. Of all phlorotannins identified so far, dieckol has shown the most potent effect in anti-inflammatory, radical scavenging and neuroprotective functions. However, whether dieckol up-regulates hemeoxygenase 1 (HO-1) and this mediates its anti-inflammatory effect in murine macrophages remains poorly understood. Dieckol (12.5-50 μM) inhibited nitric oxide production and attenuated inducible nitric oxide synthase, phospho (p)-PI-3K, p-Akt, p-IKK-α/β, p-IκB-α and nuclear p-NF-κBp65 protein expressions, and NF-κB transcriptional activity in LPS (0.1 μg/ml) stimulated murine macrophages. On the other hand, dieckol up-regulated HO-1 which partly mediated its anti-inflammatory effect in murine macrophages. Thus, dieckol appeared to be a potential therapeutic agent against inflammation through HO-1 up-regulation.

A survey of marine natural compounds and their derivatives with anti-cancer activity reported in 2011

Cancer continues to be a major public health problem despite the efforts that have been made in the search for novel drugs and treatments. The current sources sought for the discovery of new molecules are plants, animals and minerals. During the past decade, the search for anticancer agents of marine origin to fight chemo-resistance has increased greatly. Each year, several novel anticancer molecules are isolated from marine organisms and represent a renewed hope for cancer therapy. The study of structure-function relationships has allowed synthesis of analogues with increased efficacy and less toxicity. In this report, we aim to review 42 compounds of marine origin and their derivatives that were published in 2011 as promising anticancer compounds.

Resveratrol induces MMP-9 and cell migration via the p38 kinase and PI-3K pathways in HT1080 human fibrosarcoma cells

Trans-3,4',5-trihydroxystilbene (resveratrol) is a grape polyphenol present in various plants, food products, red wine and grapes. Resveratrol has anti-inflammatory, anticarcinogenic, anti-oxidant and anti-aging properties. Matrix metalloproteinases (MMPs) are key enzymes involved in the degradation of the extracellular matrix, and their expression may be regulated in cancer metastasis. In the present study, we aimed to evaluate the effect of resveratrol on MMPs and cell migration, and to understand the mechanism of action in HT1080 human fibrosarcoma cells. We found that resveratrol inhibited HT1080 cell viability at various concentrations as detected by the MTT assay and FACS analysis. However, resveratrol dramatically increased the activation and expression of MMP-9 in a dose- and time-dependent manner, as determined by gelatin zymography assay and western blot analysis. We also discovered that resveratrol enhanced the migratory ability of HT1080 cells, as determined by the wound healing assay, and decreased the phosphorylation of p38 kinase. Moreover, the Akt kinase was inhibited by resveratrol in the HT1080 cells. The inhibition of p38 and Akt kinases with SB203580 and LY294002 further increased resveratrol-induced MMP-9 as well as cell migration in the HT1080 cells. Our results suggest that resveratrol regulates MMP-9 and migratory abilities through the p38 kinase and PI-3K pathways in HT1080 human fibrosarcoma cells.