Dieckol from Ecklonia cava suppresses the migration and invasion of HT1080 cells by inhibiting the focal adhesion kinase pathway downstream of Rac1-ROS signaling

Microtubule dynamics in cancer metastasis: Harnessing the underappreciated potential for therapeutic interventions

Microtubules, dynamic cytoskeletal structures crucial for cellular processes, have surfaced as promising targets for cancer therapy owing to their pivotal role in cancer progression and metastasis. This review comprehensively explores the multifaceted landscape of microtubule-targeting drugs and their potential to inihibit cancer metastasis. Although the role of Actin cytoskeleton is well known in controlling metastasis, only recently Microtubules are emerging as a potential controller of metastasis. We delve into the processes at the core of antimetastatic impacts of microtubule-targeting agents, both through direct modulation of microtubules and via alternative pathways. Drawing from in vitro and in vivo studies, we analyze the cytotoxic and antimetastatic doses of various compounds, shedding light on their therapeutic potential. Furthermore, we discuss the emerging class of microtubule targeting drugs, and their role in metastasis inhibition, such as microtubules acetylation inhibitory drugs, particularly histone deacetylase inihibitors and antibody-drug conjugates. Histone deacetylase (HDAC) strengthens the microtubule cytoskeleton through acetylation. Recently, HDAC inhibitors have been discovered to have antimetastatic properties. Here, the role of HDAC inhibitors in stopping metastasis is discussed with respect to microtubule cytoskeleton. Surprisingly, novel antibody conjugates of microtubule-targeting agents, which are in clinical trials, were found to be antimetastatic. This review discusses these antibody conjugates in detail. Additionally, we elucidate the intricate crosstalk between microtubules and other cytoskeletal proteins, unveiling novel therapeutic strategies for metastasis suppression. By providing a wide-ranging overview of the complex interplay between microtubules and cancer metastasis, this review contributes to the comprehension of cancer's biological mechanisms and the development of innovative therapeutic interventions to mitigate metastatic progression.

Dieckol prevents prostate cancer cell proliferation by transcriptionally attenuating JAK/STAT3 signaling pathway

This study delved at how the natural substance dieckol (DCL) prevents prostate cancerous cells from proliferating and migrating by blocking the JAK/STAT3 signaling pathway in PC-3 cells. For numerous tests, the cells were treated to DCL at a range of concentrations (0-20 μM) for 24 h. DCL mediated cytotoxicity was analyzed by MTT assay. To evaluate ROS, DCFH-DA staining was employed. Dual (AO/EtBr) staining was utilized to examine apoptotic changes, and MMP levels in PC-3 cells were examined using the appropriate fluorescent staining assays. By using flow cytometry and western blotting, the protein expressions of cell survival, cell cycle, proliferation, and apoptosis were assessed. The results showed that DCL significantly cytotoxically affects PC-3, and the IC50 was discovered to be 12 μM for 24 h exposure. Furthermore, after DCL treatment in PC-3, considerable ROS generation and increased apoptotic signals were detected. STAT3, JAK1, PCNA, and cyclins D1 and E1 are all suppressed by DCL in PC-3. In addition, DCL therapy in PC-3 dramatically increased pro-apoptotic proteins such Bax, caspase-3, and cytochrome C. Therefore, DCL has been regarded as a chemotherapeutic agent because to its ability to decrease the expression of proteins that control cell proliferation, including STAT3, JAK1, PCNA, and cyclins D1 and E1.

Natural Products and Pharmacological Properties of Symbiotic Bacillota (Firmicutes) of Marine Macroalgae

The shift from the terrestrial to the marine environment to discover natural products has given rise to novel bioactive compounds, some of which have been approved for human medicine. However, the ocean, which makes up nearly three-quarters of the Earth's surface, contains macro- and microorganisms whose natural products are yet to be explored. Among these underexplored marine organisms are macroalgae and their symbiotic microbes, such as Bacillota, a phylum of mostly Gram-positive bacteria previously known as Firmicutes. Macroalgae-associated Bacillota often produce chemical compounds that protect them and their hosts from competitive and harmful rivals. Here, we summarised the natural products made by macroalgae-associated Bacillota and their pharmacological properties. We discovered that these Bacillota are efficient producers of novel biologically active molecules. However, only a few macroalgae had been investigated for chemical constituents of their Bacillota: nine brown, five red and one green algae. Thus, Bacillota, especially from the marine habitat, should be investigated for potential pharmaceutical leads. Moreover, additional diverse biological assays for the isolated molecules of macroalgae Bacillota should be implemented to expand their bioactivity profiles, as only antibacterial properties were tested for most compounds.

Phlorotannins: Novel Orally Administrated Bioactive Compounds That Induce Mitochondrial Dysfunction and Oxidative Stress in Cancer

Mitochondrial dysfunction is an interesting therapeutic target to help reduce cancer deaths, and the use of bioactive compounds has emerged as a novel and safe approach to solve this problem. Here, we discuss the information available related to phlorotannins, a type of polyphenol present in brown seaweeds that reportedly functions as antioxidants/pro-oxidants and anti-inflammatory and anti-tumorigenic agents. Specifically, available evidence indicates that dieckol and phloroglucinol promote mitochondrial membrane depolarization and mitochondria-dependent apoptosis. Phlorotannins also reduce pro-tumorigenic, -inflammatory, and -angiogenic signaling mechanisms involving RAS/MAPK/ERK, PI3K/Akt/mTOR, NF-κB, and VEGF. In doing so, they inhibit pathways that favor cancer development and progression. Unfortunately, these compounds are rather labile and, therefore, this review also summarizes approaches permitting the encapsulation of bioactive compounds, like phlorotannins, and their subsequent oral administration as novel and non-invasive therapeutic alternatives for cancer treatment.

Dieckol, a natural polyphenolic drug, inhibits the proliferation and migration of colon cancer cells by inhibiting PI3K, AKT, and mTOR phosphorylation

This study investigated that dieckol (DKL), a natural drug, inhibits colon cancer cell proliferation and migration by inhibiting phosphoinositide-3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR) phosphorylation in HCT-116 cells. The cells were treated with DKL in various concentrations (32 and 50 μM) for 24 h and then analyzed for various experiments. MTT (tetrazolium bromide) and crystal violet assay investigated DKL-mediated cytotoxicity. Dichlorodihydrofluorescein diacetate staining was used to assess the reactive oxygen species (ROS) measurement, and apoptotic changes were studied by dual acridine orange and ethidium bromide staining. Protein expression of cell survival, cell cycle, proliferation, and apoptosis protein was evaluated by western blot analysis. Results indicated that DKL produces significant cytotoxicity in HCT-116, and the half-maximal inhibitory concentration was found to be 32 μM for 24-h incubation. Moreover, effective production of ROS and enhanced apoptotic signs were observed upon DKL treatment in HCT-116. DKL induces the expression of phosphorylated PI3K, AKT, and mToR-associated enhanced expression of cyclin-D1, proliferating cell nuclear antigen, cyclin-dependent kinase (CDK)-4, CDK-6, and Bcl-2 in HCT-116. In addition, proapoptotic proteins such as Bax, caspase-9, and caspase-3 were significantly enhanced by DKL treatment in HCT-116. Hence, DKL has been considered a chemotherapeutic drug by impeding the expression of PI3K-, AKT-, and mTOR-mediated inhibition of proliferation and cell cycle-regulating proteins.

Combination of marine bioactive compounds and extracts for the prevention and treatment of chronic diseases

Background

In recent years, marine-based functional foods and combination therapy are receiving greater recognition for their roles in healthy lifestyle applications and are being investigated as viable and effective strategies for disease treatment or prevention.

Aim of the review

This review article presents and discusses the relevant scientific publications that have studied the synergistic and additive effects of natural marine bioactive compounds and extract combinations with anti-obesity, anti-inflammatory, antioxidant, and chemopreventive activities in the last two decades. The paper presents the mechanism of action and health benefits of developed combinations and discusses the limitation of the studies. Furthermore, it recommends alternatives and directions for future studies. Finally, it highlights the factors for developing novel combinations of marine bioactive compounds.

Key scientific concepts of review

Combination of marine bioactive compounds or extracts affords synergistic or additive effects by multiple means, such as multi-target effects, enhancing the bioavailability, boosting the bioactivity, and neutralizing adverse effects of compounds in the mixture. For the development of marine-based combinations, there are key points for consideration and issues to address: knowledge of the mechanism of action of individual compounds and their combinations, optimum ratio and dosing of compounds, and experimental models must all be taken into account. Strategies to increase the number and diversity of marine combinations, and further development of marine-based functional foods, are available. However, only a small number of natural marine bioactive combinations have been assessed, and most research has been focused on fish oil and carotenoid synergy. Therefore, more research and resources should be spent on developing novel marine bioactive combinations as functional foods and nutraceuticals.

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 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.

Antiosteoporosis and bone protective effect of dieckol against glucocorticoid-induced osteoporosis in rats

BACKGROUND

Glucocorticoids (GCs) induce osteoporosis, which results in fractures in the bond, causing significant morbidity. In the conducted study, we examined the antiosteoporosis effect of dieckol against GC-induced osteoporosis in rats.

METHODS

Sprague-Dawley (SD) rats were used for the current study and dexamethasone (2.5 mg/kg) induced osteoporosis in the rats that received the dieckol (test) and alendronate (standard) for 20 weeks. Bone turnover parameters, microCT, antioxidant, inflammatory cytokines, nutrient, and hormones parameters.

RESULTS

Dieckol noticeably suppressed the body weight and boosted the uterine and vagina weight. Dieckol considerably altered the level of trabecular number (Tb. N), the bone volume to total volume (BV/TV), trabecular separation (Tb.Sp), bone surface to bone volume (BS/BV), and t​r​a​b​e​c​u​l​a​r thickness (Tb.Th). Dieckol noticeably (P < 0.001) elevated the level of osteocalcin (OC) and alleviated the level of bone Gla protein (BGP), acid phosphatase (ACP), alkaline phosphatase (ALP), and β-CTx. Dieckol markedly boosted the level of malondialdehyde (MDA) and suppressed the level of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) along with the suppression of inflammatory cytokines like TNF-α, IL-1β, and IL-6. Dieckol remarkably increased the level of calcium, potassium, magnesium, and 25 (OH) vitamin D. Dieckol substantially (P < 0.001) boosted the level of estradiol and alleviated the level of parathyroid hormone and tartrate-resistant acid phosphatase (TRAP). Dieckol also suppressed the level of receptor activator of nuclear factor κB ligand (RANKL) and boosted the level of osteoprotegerin (OPG).

CONCLUSION

Taken together, our data suggest that dieckol demonstrated the anti-osteoporosis effect against GC-induced osteoporosis in rats.

Dieckol alleviates dextran sulfate sodium-induced colitis via inhibition of inflammatory pathway and activation of Nrf2/HO-1 signaling pathway

Ulcerative colitis (UC) is the major type of inflammatory ailment with elevated prevalence worldwide. Dieckol (DEK) is a phlorotannin that is extensively found in marine algae and has been found to have different pharmacological properties. Nevertheless, the impact of DEK in UC has not been investigated earlier. Therefore, we appraised DEK's function in dextran sulfate sodium (DSS)-induced UC in the mouse. An overall of 30 mice was randomized into 5 equal groups. Control mice treated with a standard diet (group I), colitis mice challenged with 3% of DSS through drinking water for 7 consecutive days (group II), DEK was supplemented via oral gavage from day 1 to 10 at the dosages of 5, 10, and 15 mg/kg b.wt, respectively. All animals were sacrificed on the 11th day. The body weight (bwt), colon length, disease activity index, malondialdehyde (MDA), myeloperoxidase (MPO), and histological features were observed using suitable techniques, and COX-2 expression was investigated by immunohistochemistry. Moreover, TNF-α, IL-1β, p65, IκBα, HO-1, and Nrf2 expressions were measured using ELISA and RT-PCR techniques, respectively. DEK treatment to the colitis mice considerably lessened, DSS-challenged alterations in body weight, DAI, colonic length shortening and histological changes. DEK exhibited potent antioxidant effects due to the reduced MDA and MPO, and Nrf2 expression markers while the HO-1 marker was augmented. Additionally, DEK also suppressed the expression s of TNF-α, IL-1β, and the p-p65, p-IκBα, and p65 and augmented the expression of IκBα, which eventually proved the anti-inflammatory potential of DEK against the DSS-challenge. Based on these results, DEK has been found effective in mitigating colitis, conceivably alleviating colon inflammation through the NF-κB inhibition and triggering of Nrf2/HO-1 signaling cascade.

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.

Dieckol inhibits non-small-cell lung cancer cell proliferation and migration by regulating the PI3K/AKT signaling pathway

Non-small-cell lung cancer (NSCLC) is one of the most prevalent type of lung cancers with an increased mortality rate in both developed and developing countries worldwide. Dieckol is one such polyphenolic drug extracted from brown algae which has proven antioxidant and anti-inflammatory properties. In the present study, we evaluated the anticancer property of dieckol against NSCLC cell line A549. The LC50 value of dieckol was found to be 25 µg/mL by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the antiapoptotic property of dieckol was analyzed by dual staining technique with acridine orange/propidium iodide (AO/PI) stains. It was further confirmed with flow cytometry analysis with Annexin FITC and JC-1 staining and the anti-invasive property was assessed by Transwell assay. The molecular mechanism of dieckol anticancer activity was confirmed by estimating the levels of caspases and by estimating the signaling proteins of Pi3K/AKT/mTOR signaling pathway using the immunoblotting technique. Our data suggest that dieckol is potent anticancer agent, it effectively inhibits the invasive and migratory property A549 cells and it also induces apoptosis via inhibiting Pi3K/AKT/mTOR signaling, activating the tumor suppressor protein E-cadherin signifying that dieckol is potent natural anticancer drug to treat NSCLC.

Algae metabolites: from in vitro growth inhibitory effects to promising anticancer activity

Covering: 1957 to 2017 Algae constitute a heterogeneous group of eukaryotic photosynthetic organisms, mainly found in the marine environment. Algae produce numerous metabolites that help them cope with the harsh conditions of the marine environment. Because of their structural diversity and uniqueness, these molecules have recently gained a lot of interest for the identification of medicinally useful agents, including those with potential anticancer activities. In the current review, which is not a catalogue-based one, we first highlight the major biological events that lead to various types of cancer, including metastatic ones, to chemoresistance, thus to any types of current anticancer treatment relating to the use of chemotherapeutics. We then review algal metabolites for which scientific literature reports anticancer activity. Lastly, we focus on algal metabolites with promising anticancer activity based on their ability to target biological characteristics of cancer cells responsible for poor treatment outcomes. Thus, we highlight compounds that have, among others, one or more of the following characteristics: selectivity in reducing the proliferation of cancer cells over normal ones, potential for killing cancer cells through non-apoptotic signaling pathways, ability to circumvent MDR-related efflux pumps, and activity in vivo in relevant pre-clinical models.

Radioprotective efficacy of dieckol against gamma radiation-induced cellular damage in hepatocyte cells

Naturally occurring antioxidants prevent or delay the harmful effect of free radical formation and radioprotection. The present study aimed to investigate the radioprotective effect of dieckol, a naturally occurring marine bioactive phenolic compound on lipid peroxidation and antioxidant status, DNA damage, and inflammation in gamma-radiation-induced rat primary hepatocytes. Isolated hepatocyte cells exposed to gamma-radiation showed an increased level of lipid peroxidation markers (thiobarbituric acid reactive substances and lipid hydroperoxides) accompanied with the decrease in the activities of enzymatic (SOD, CAT, and GPx) and non-enzymatic (vitamin C, vitamin E, and GSH) antioxidants associated with increased DNA damage coupled with upregulation of inflammatory proteins (NF-κB and COX-2) compared to control. Treatment of dieckol (5, 10, 20 μM) reduces the γ-radiation-induced toxicity and the associated pro-oxidant and antioxidant imbalance as well as decreasing the DNA damage (tail length, tail moment, %DNA in a tail and olive tail moment) and inflammation in hepatocyte cells. These findings indicate that treatment of dieckol offers protection against γ-radiation-induced cellular damage in the liver cells.

Polyphenols from brown alga, Padina boergesenii (Allendar & Kraft) decelerates renal cancer growth involving cell cycle arrest and induction of apoptosis in renal carcinoma cells

In our previous work, we assessed the ameliorative effect of crude extract from Padina boergesenii. In this report, we have extended these study by fractionating the methanol extract with methanol:ethylacetate (1:3,v/v) (MME-F) and assessed the cytotoxic effect of MME-F fraction in human renal carcinoma cell lines (A498 and ACHN). The fraction had time-and dose-dependent inhibition of cancer cell proliferation, migration with deceleration of cancer growth at EC50 -22.73 μg in A498 and 26.43 μg in ACHN cells. Cells treated at EC50 value 25 μg displayed twofold greater ability to induce early and late stage of apoptosis. The cells treated with polyphenolic fraction (MME-F) induced cell cycle arrest at G2/M phase. HPLC/DAD chromatographic procedures quantified polyphenols from active fraction (MME-F). These data revealed the functional activity of polyphenols from brown alga, P. boergesenii as a potent inhibitor of cancer proliferation with induction of apoptosis, it suggest their applicability in preventing cancer metastasis.

From Marine Origin to Therapeutics: The Antitumor Potential of Marine Algae-Derived Compounds

Marine environment has demonstrated to be an interesting source of compounds with uncommon and unique chemical features on which the molecular modeling and chemical synthesis of new drugs can be based with greater efficacy and specificity for the therapeutics. Cancer is a growing public health threat, and despite the advances in biomedical research and technology, there is an urgent need for the development of new anticancer drugs. In this field, it is estimated that more than 60% of commercially available anticancer drugs are natural biomimetic inspired. Among the marine organisms, algae have revealed to be one of the major sources of new compounds of marine origin, including those exhibiting antitumor and cytotoxic potential. These compounds demonstrated ability to mediate specific inhibitory activities on a number of key cellular processes, including apoptosis pathways, angiogenesis, migration and invasion, in both in vitro and in vivo models, revealing their potential to be used as anticancer drugs. This review will focus on the bioactive molecules from algae with antitumor potential, from their origin to their potential uses, with special emphasis to the alga Sphaerococcus coronopifolius as a producer of cytotoxic compounds.

CML/CD36 accelerates atherosclerotic progression via inhibiting foam cell migration

Among the various complications of type 2 diabetes mellitus, atherosclerosis causes the highest disability and morbidity. A multitude of macrophage-derived foam cells are retained in atherosclerotic plaques resulting not only from recruitment of monocytes into lesions but also from a reduced rate of macrophage migration from lesions. Nε-carboxymethyl-Lysine (CML), an advanced glycation end product, is responsible for most complications of diabetes. This study was designed to investigate the mechanism of CML/CD36 accelerating atherosclerotic progression via inhibiting foam cell migration. In vivo study and in vitro study were performed. For the in vivo investigation, CML/CD36 accelerated atherosclerotic progression via promoting the accumulation of macrophage-derived foam cells in aorta and inhibited macrophage-derived foam cells in aorta migrating to the para-aorta lymph node of diabetic apoE^-/- mice. For the in vitro investigation, CML/CD36 inhibited RAW264.7-derived foam cell migration through NOX-derived ROS, FAK phosphorylation, Arp2/3 complex activation and F-actin polymerization. Thus, we concluded that CML/CD36 inhibited foam cells of plaque migrating to para-aorta lymph nodes, accelerating atherosclerotic progression. The corresponding mechanism may be via free cholesterol, ROS generation, p-FAK, Arp2/3, F-actin polymerization.

Loss of p16INK4A stimulates aberrant mitochondrial biogenesis through a CDK4/Rb-independent pathway

The tumor suppressor p16INK4A (p16) inhibits cell cycle progression through the CDK4/Rb pathway. We have previously shown that p16 regulates cellular oxidative stress, independent of its role in cell cycle control. We investigated whether loss of p16 had a direct impact on the mitochondria. We found that p16-null primary mouse fibroblasts (PMFs) displayed increased mitochondrial mass and expression of mitochondrial respiratory subunit proteins compared to wild-type (WT) PMFs. These findings in p16-null PMFs were associated with increased expression of the mitochondrial biogenesis transcription factors PRC and TFAM. On the other hand, p16-deficient PMFs demonstrated reduced mitochondrial respiration capacity consistent with electron microscopy findings showing that mitochondria in p16-deficient PMFs have abnormal morphology. Consistent with increased mitochondrial mass and reduced respiratory capacity, p16-deficient PMFs generated increased mitochondrial superoxide. One biological consequence of elevated ROS in p16-deficient PMFs was enhanced migration, which was reduced by the ROS scavenger N-acetylcysteine. Finally, p16-deficient PMFs displayed increased mitochondrial membrane potential, which was also required for their enhanced migration. The mitochondrial and migration phenotype was restored in p16-deficient PMFs by forced expression of p16. Similarly, over-expression of p16 in human melanocytes and A375 melanoma cells led to decreased expression of some mitochondrial respiratory proteins, enhanced respiration, and decreased migration. Inhibition of Rb phosphorylation in melanocytes and melanoma cells, either by addition of chemical CDK4 inhibitors or RNAi-mediated knockdown of CDK4, did not mimic the effects of p16 loss. These results suggest that p16 regulates mitochondrial biogenesis and function, which is independent of the canonical CDK4/Rb pathway.

Modulatory efficacy of dieckol on xenobiotic-metabolizing enzymes, cell proliferation, apoptosis, invasion and angiogenesis during NDEA-induced rat hepatocarcinogenesis

Dieckol (DEK) is a major polyphenol of marine brown seaweed Ecklonia cava which is a potential candidate for cancer therapy. However, the underlying mechanism of DEK as an anticancer drug remains to be elucidated. In this study, we evaluated the molecular mechanisms involved in the chemopreventive efficacy of DEK in N-nitrosodiethylamine (NDEA)-induced hepatocarcinogenesis rats by analyzing markers of xenobiotic-metabolizing enzymes (XMEs), apoptosis, invasion, and angiogenesis. Rats administered NDEA developed hepatocarcinogenesis that displayed apoptosis avoidance coupled to upregulation of pro-inflammatory, invasion, and angiogenesis markers. Treatment of DEK effectively suppressed the NDEA-initiated hepatocarcinogenesis by modulation of XMEs, inducing of apoptosis via the mitochondrial pathway as revealed by modulating the Bcl-2 family proteins, cytochrome C, caspases, and inhibiting invasion, and angiogenesis as evidenced by changes in the activities of MMPs (MMP2/9) and the expression of VEGF. In addition, DEK exerts its anticancer effects via inhibition of pro-inflammatory transcription factor NF-κB (nuclear factor κB) and COX2 in NDEA-induced hepatocarcinogenesis. Taken together, this study demonstrates that DEK modulates the expression of key molecules that regulate apoptosis, inflammation, invasion, and angiogenesis. These results strongly indicate that DEK from E. cava is an attractive candidate for chemoprevention.

Homodimers of Vanillin and Apocynin Decrease the Metastatic Potential of Human Cancer Cells by Inhibiting the FAK/PI3K/Akt Signaling Pathway

The spread of cancer cells to distant organs, in a process called metastasis, is the main factor that contributes to most death in cancer patients. Vanillin, the vanilla flavoring agent, has been shown to suppress metastasis in a mouse model. Here, we evaluated the antimetastatic potential of the food additive divanillin, the homodimer of vanillin, and their structurally related compounds, apocynin and diapocynin, in hepatocellular carcinoma cells. The Transwell invasion assay showed that the dimeric forms exhibited a potency higher than those of vanillin and apocynin in inhibiting invasion, with IC₅₀ values of 23.3 ± 7.4 to 41.3 ± 4.2 μM for the dimers, which are 26-34-fold lower than IC₅₀ values of vanillin and apocynin (p < 0.05). Both monomeric and dimeric forms target regulation of the invasion process by inhibiting phosphorylation of FAK and Akt. Molecular docking studies suggested that the dimers should bind more tightly than vanillin and apocynin to the Y397 pocket of the FAK FERM domain. Thus, the food additive divanillin has antimetastatic potential greater than that of the flavoring agent vanillin.

Enzyme-treated Ecklonia cava extract inhibits adipogenesis through the downregulation of C/EBPα in 3T3-L1 adipocytes

In this study, we examined the inhibitory effects of enzyme- treated Ecklonia cava (EEc) extract on the adipogenesis of 3T3-L1 adipocytes. The components of Ecklonia cava (E. cava) were first separated and purified using the digestive enzymes pectinase (Rapidase® X‑Press L) and cellulase (Rohament® CL). We found that the EEc extract contained three distinct phlorotannins: eckol, dieckol and phlorofucofuroeckol-A. Among the phlorotannins, dieckol was the most abundant in the EEc extract at 16 mg/g. Then we examined the inhibitory effects of EEc extract treatment on differentiation‑related transcription factors and on adipogenesis‑related gene expression in vitro using 3T3-L1 adipocytes. 3T3‑L1 pre‑adipocytes were used to determine the concentrations of the EEc extract and Garcinia cambogia (Gar) extract that did not result in cytotoxicity. Glucose utilization and triglyceride (TG) accumulation in the EEc‑treated adipocytes were similarly inhibited by 50 µg/ml EEc and 200 µg/ml Gar, and these results were confirmed by Oil Red O staining. Protein expression of adipogenesis differentiation‑related transcription factors following treatment with the EEc extract was also examined. Only the expression of CCAAT/enhancer‑binding protein (C/EBP)α was decreased, while there was no effect on the expression of C/EBPβ, C/EBPδ, and peroxisome proliferator‑activated receptor γ (PPARγ). Treatment with the EEc extract decreased the expression levels of adipogenesis‑related genes, in particular sterol regulatory element binding protein‑1c (SREBP‑1c), adipocyte fatty acid binding protein (A‑FABP), fatty acid synthase (FAS) and adiponectin. These results suggest that EEc extract treatment has an inhibitory effect on adipogenesis, specifically by affecting the activation of the C/EBPα signaling pathway and the resulting adipogenesis-related gene expression.

Rhein suppresses matrix metalloproteinase production by regulating the Rac1/ROS/MAPK/AP-1 pathway in human ovarian carcinoma cells

Matrix metalloproteinases (MMPs) are a family of calcium-dependent zinc-containing endopeptidases, which play an integral role in migration and invasion of ovarian cancer. Rac1 proteins might mostly influence cell migration and invasion by generating endogenous reactive oxygen species. Therefore, inhibiting MMPs and regulating the Rac1/ROS/MAPK/AP-1 pathway may be a new therapeutic strategy for ovarian cancer. In this study, we found that rhein could suppress the invasion and migration of SKOV3-PM4 cells with characteristics of directional highly lymphatic metastasis. Phorbol 12-myristate 13-acetate (PMA), which is a Rac1 activator, significantly enhanced the expression levels of MMP-2, -3, -9 and -19 proteins, whereas the results of rhein and Rac1 inhibitor NSC23766 were just the opposite. The inhibitory effects of rhein were associated with the upregulation of tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2 and NM23-H1. Subsequent mechanism studies revealed that rhein reduce the production of reactive oxygen species (ROS) and lower NADPH oxidase activity. Furthermore, rhein significantly inhibited JNK, AP-1 phosphorylation in the cells treated with PMA. The results obtained from the cells treated with NSC23766 alone or NSC23766 combined with rhein, were consistent with rhein treatment alone. Taken together, these results indicate that rhein may be a potential inhibitor of Rac1 and can inhibit the migration and invasion of SKOV3-PM4 cells through modulating matrix metalloproteinases and RAC1/ROS/MAPK/AP-1 signaling pathway-associated proteins.

Inhibitory effects of dieckol on hypoxia-induced epithelial-mesenchymal transition of HT29 human colorectal cancer cells

Hypoxia-induced epithelial-mesenchymal transition (EMT) has been identified as essential for tumor progression and metastasis. The present study examined the effects of an antioxidant, dieckol, on hypoxia-induced EMT in HT29 human colorectal cancer cells. HT29 cells were treated with a hypoxia-inducing agent, CoCl₂, and an increase in the levels of intracellular reactive oxygen species (ROS) and various morphological changes, such as loss of cell-cell contact and aggressive cell migration were observed. CoCl₂ also induced an increase in the expression of hypoxia-inducible factor 1α (HIF1α) and various mesenchymal-specific markers, including vimentin and snail family transcriptional repressor 1 (Snail1), and a decrease in the expression of E-cadherin, thus suggesting that CoCl₂ induced EMT in HT29 cells. Conversely, the CoCl₂-induced EMT of HT29 cells was suppressed following treatment with dieckol. In addition, ROS generation, EMT marker protein expression and intracellular localization, cell migration and cell invasion were attenuated following dieckol treatment. The findings of the present study suggested that dieckol may inhibit hypoxia-induced EMT in HT29 cells by regulating the levels of cellular ROS and protein expression levels downstream of the HIF1α signaling pathway. Therefore, dieckol has the potential to become an attractive therapeutic agent for the treatment of colorectal cancer.

Autophagy is associated with cell fate in the process of macrophage-derived foam cells formation and progress

Background

Autophagy participates in plaque formation and progression; however, its association with foam cells’ fate is unknown. To investigate autophagy features and its effect on the fate of different-stage macrophage foam cells (FCs). Different-stage FCs were obtained through incubation of THP-1 macrophages (THP-M) with oxidized low-density lipoprotein LDL (oxLDL, 80 μg/mL) for various durations (0–72 h). Autophagy in THP-1 macrophage FCs and in apoE−/− mice was regulated by Rapamycin (80 ug/mL) or 3-MA (10 mM). Lipid droplet accumulation, LC3 I/II, P62 expression level, and autophagic flux were measured. Vascular ultrasound, TUNEL, IHC, and DHE staining were used to detect the artery plaques in apoE−/− mice.

Results

In early-stage FCs, the amount of autophagosomes gradually increased, and autophagic flux intensity accelerated, but in mid-late stage FCs, autophagic flux was suppressed. For early stage FCs, treatment with autophagy activator rapamycin markedly decreased intracellular lipid content and prevented them from transforming into foam cells, while the autophagy inhibitor 3-MA considerably increased the intracellular lipid-droplet accumulation. During the process of foam cell development, upregulating autophagy not only reduced intracellular lipid-droplet accumulation, but also inhibited cell apoptosis through clearing dysfunctional mitochondria and lowering intracellular ROS level. The in vivo experiments produced consistent results that rapamycin administration in apoE−/− mice reduced the death rate of macrophages and delayed plaque progression.

Conclusions

The fate of macrophage FCs was associated with autophagy. Early autophagy enhancement inhibits the formation and progression of macrophage FCs and prevents atherosclerosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-016-0274-z) contains supplementary material, which is available to authorized users.

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.

Dieckol, a Component of Ecklonia cava, Suppresses the Production of MDC/CCL22 via Down-Regulating STAT1 Pathway in Interferon-γ Stimulated HaCaT Human Keratinocytes

Macrophage-derived chemokine, C-C motif chemokine 22 (MDC/CCL22), is one of the inflammatory chemokines that controls the movement of monocytes, monocyte-derived dendritic cells, and natural killer cells. Serum and skin MDC/CCL22 levels are elevated in atopic dermatitis, which suggests that the chemokines produced from keratinocytes are responsible for attracting inflammatory lymphocytes to the skin. A major signaling pathway in the interferon-γ (IFN-γ)-stimulated inflammation response involves the signal transducers and activators of transcription 1 (STAT1). In the present study, we investigated the anti-inflammatory effect of dieckol and its possible action mechanisms in the category of skin inflammation including atopic dermatitis. Dieckol inhibited MDC/CCL22 production induced by IFN-γ (10 ng/mL) in a dose dependent manner. Dieckol (5 and 10 μM) suppressed the phosphorylation and the nuclear translocation of STAT1. These results suggest that dieckol exhibits anti-inflammatory effect via the down-regulation of STAT1 activation.

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.

Cyclic mechanical stretching promotes migration but inhibits invasion of rat bone marrow stromal cells

Bone marrow stromal cells (BMSCs, also broadly known as bone marrow-derived mesenchymal stem cells) are multipotent stem cells that have a self-renewal capacity and multilineage differentiation potential. Mechanical stretching plays a vital role in regulating the proliferation and differentiation of BMSCs. However, little is known about the effects of cyclic stretching on BMSC migration and invasion. In this study, using a custom-made cell-stretching device, we studied the effects of cyclic mechanical stretching on rat BMSC migration and invasion using a Transwell Boyden Chamber. The protein secretion of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) was detected by gelatin zymography, and the activation of focal adhesion kinase (FAK) and extracellular signal regulated kinase1/2 (ERK1/2) was measured by western blot. We found that cyclic mechanical stretching with 10% amplitude at 1Hz frequency for 8h promotes BMSC migration, but reduces BMSC invasion. FAK and ERK1/2 signals were activated in BMSCs after exposure to cyclic stretching. In the presence of the FAK phosphorylation blocker PF573228 or the ERK1/2 phosphorylation blocker PD98059, the cyclic-stretch-promoted migration of BMSCs was completely suppressed. On the other hand, cyclic mechanical stretching reduced the secretion of MMP-2 and MMP-9 in BMSCs, and PF573228 suppressed the cyclic-stretch-reduced secretion of MMP-2 and MMP-9. The decrease of BMSC invasion induced by mechanical stretching is partially restored by PF573228 but remained unaffected by PD98059. Taken together, these data show that cyclic mechanical stretching promotes BMSC migration via the FAK-ERK1/2 signalling pathway, but reduces BMSC invasion by decreasing secretion of MMP-2 and MMP-9 via FAK, independent of the ERK1/2 signal.

Antioxidant Peptide Derived fromSpirulina maximaSuppresses HIF1-Induced Invasive Migration of HT1080 Fibrosarcoma Cells

Hypoxia causes the malignant progression of tumor cells; hence, it has been considered a central issue that must be addressed for effective cancer therapy. The initiation of tumor metastasis requires invasive cell migration. Here, we show that an antioxidant peptide derived fromSpirulina maximasuppresses hypoxia-induced invasive migration of HT1080 human fibrosarcoma cells. HT1080 cells treated with a hypoxia-inducing agent, CoCl2, exhibited an increase in invasive migration and intracellular reactive oxygen species (ROS), which is associated with an increase in the expression of hypoxia-induced factor 1α(HIF1α) accompanied by the activation of PI3K/Akt and ERK1/2. The inhibition of PI3K/Akt and ERK1/2 with specific inhibitors diminished the CoCl2-induced increase in HIF1αexpression and invasive cell migration. Moreover, CoCl2-induced HIF1αexpression was associated with an increase in the expression of molecules downstream ofβ-integrin, such as N-cadherin, vimentin, andβ-catenin. Therefore, theS. maximapeptide effectively attenuated the CoCl2-induced ROS generation and downregulated the HIF1αsignaling pathway involving PI3K/Akt, ERK1/2, andβ-integrin in cells. These results suggest that theS. maximaantioxidant peptide downregulates the HIF1αsignaling pathway necessary for hypoxia-induced invasive migration of HT1080 cells by attenuating intracellular ROS.S. maximapeptide may be an effective constituent in antitumor progression products.

8,8'-Bieckol, isolated from edible brown algae, exerts its anti-inflammatory effects through inhibition of NF-κB signaling and ROS production in LPS-stimulated macrophages

Ecklonia cava (E. cava) is an abundant brown alga that contains high levels of phlorotannins, which are unique marine polyphenolic compounds. It has been suggested that E. cava phlorotannins exert anti-inflammatory effects. However, the anti-inflammatory effects and underlying molecular mechanism exerted by 8,8'-bieckol isolated from E. cava have not been reported. Thus, in this study, we examined the anti-inflammatory effects of 8,8'-bieckol on lipopolysaccharide (LPS)-stimulated primary macrophages and RAW 264.7 macrophages. We found that 8,8'-bieckol suppressed key inflammatory mediator [i.e., nitric oxide (NO) and prostaglandin E2 (PGE2)] production in both primary and RAW 264.7 macrophages. 8,8'-Bieckol inhibited NO by suppressing LPS-induced expression of inducible nitric oxide synthase (iNOS) at the mRNA and protein levels in primary macrophages and RAW 264.7 cells. In addition, 8,8'-bieckol decreased the production and mRNA expression of the inflammatory cytokine interleukin-6 (IL-6), but not tumor necrosis factor (TNF)-α, in RAW 264.7 cells. Moreover, 8,8'-bieckol treatment diminished transactivation of nuclear factor-kappa B (NF-κB) and nuclear translocation of the NF-κB p65 subunit and suppressed LPS-induced intracellular reactive oxygen species (ROS) production in macrophages. Furthermore, 8,8'-bieckol markedly reduced mortality in LPS-induced septic mice. Taken together, these data indicate that the anti-inflammatory properties of 8,8'-bieckol are associated with the suppression of NO, PGE2, and IL-6 via negative regulation of the NF-κB pathway and ROS production in LPS-stimulated RAW 264.7 cells. Moreover, 8,8'-bieckol protects mice from endotoxin shock.

A novel synthetic small molecule YH-306 suppresses colorectal tumour growth and metastasis via FAK pathway

Cell migration and invasion are key processes in the metastasis of cancer, and suppression of these steps is a promising strategy for cancer therapeutics. The aim of this study was to explore small molecules for treating colorectal cancer (CRC) and to investigate their anti-metastatic mechanisms. In this study, six CRC cell lines were used. We showed that YH-306 significantly inhibited the migration and invasion of CRC cells in a dose-dependent manner. In addition, YH-306 inhibited cell adhesion and protrusion formation of HCT116 and HT-29 CRC cells. Moreover, YH-306 potently suppressed uninhibited proliferation in all six CRC cell lines tested and induced cell apoptosis in four cell lines. Furthermore, YH-306 inhibited CRC colonization in vitro and suppressed CRC growth in a xenograft mouse model, as well as hepatic/pulmonary metastasis in vivo. YH-306 suppressed the activation of focal adhesion kinase (FAK), c-Src, paxillin, and phosphatidylinositol 3-kinases (PI3K), Rac1 and the expression of matrix metalloproteases (MMP) 2 and MMP9. Meanwhile, YH-306 also inhibited actin-related protein (Arp2/3) complex-mediated actin polymerization. Taken together, YH-306 is a candidate drug in preventing growth and metastasis of CRC by modulating FAK signalling pathway.

High-glucose inhibits human fibroblast cell migration in wound healing via repression of bFGF-regulating JNK phosphorylation

One of the major symptoms of diabetes mellitus (DM) is delayed wound healing, which affects large populations of patients worldwide. However, the underlying mechanism behind this illness remains elusive. Skin wound healing requires a series of coordinated processes, including fibroblast cell proliferation and migration. Here, we simulate DM by application of high glucose (HG) in human foreskin primary fibroblast cells to analyze the molecular mechanism of DM effects on wound healing. The results indicate that HG, at a concentration of 30 mM, delay cell migration, but not cell proliferation. bFGF is known to promote cell migration that partially rescues HG effects on cell migration. Molecular and cell biology studies demonstrated that HG enhanced ROS production and repressed JNK phosphorylation, but did not affect Rac1 activity. JNK and Rac1 activation were known to be important for bFGF regulated cell migration. To further confirm DM effects on skin repair, a type 1 diabetic rat model was established, and we observed the efficacy of bFGF on both normal and diabetic rat skin repair. Furthermore, proteomic studies identified an increase of Annexin A2 protein nitration in HG-stressed fibroblasts and the nitration was protected by activation of bFGF signaling. Treatment with FGFR1 and JNK inhibitors delayed cell migration and increased Annexin A2 nitration levels, indicating that Annexin A2 nitration is modulated by bFGF signaling via activation of JNK. Together with these results, our data suggests that the HG-mediated delay of cell migration is linked to the inhibition of bFGF signaling, specifically through JNK suppression.

Potential matrix metalloproteinase inhibitors from edible marine algae: a review

Matrix metalloproteinases are endopeptidases which belong to the group of metalloproteinases that contribute for the extra-cellular matrix degradation, and several tissue remodeling processes. An imbalance in the regulation of these endopeptidases eventually leads to several severe pathological complications like cancers, cardiac, cartilage, and neurological related diseases. Hence inhibitory substances of metalloproteinases (MMPIs) could prove beneficial in the management of above specified pathological conditions. The available synthetic MMPIs that have been reported until now have few shortcomings and thus many of them could not make to the final clinical trials. Hence a growing interest among researchers on screening of MMPIs from different natural resources is evident and especially natural products from marine origin. As there has been an unparalleled contribution of several biologically active compounds from marine resources that have shown profound applications in nutraceuticals, cosmeceuticals, and pharmaceuticals, we have attempted to discuss the various MMPIs from edible sea-weeds.

Marine low molecular weight natural products as potential cancer preventive compounds

Due to taxonomic positions and special living environments, marine organisms produce secondary metabolites that possess unique structures and biological activities. This review is devoted to recently isolated and/or earlier described marine compounds with potential or established cancer preventive activities, their biological sources, molecular mechanisms of their action, and their associations with human health and nutrition. The review covers literature published in 2003–2013 years and focuses on findings of the last 2 years.

Downregulated Krüppel-like factor 8 is involved in decreased trophoblast invasion under hypoxia-reoxygenation conditions

Krüppel-like factor 8 (KLF8) is a pivotal transcription factor expressed in the human placenta that can regulate cell invasion. The objective of this study was to assess whether a hypoxia-reoxygenation (H/R) environment affects placental KLF8 expression levels and subcellular localization and to evaluate the relationship between KLF8 levels and trophoblast invasion activity. Human first trimester villous tissues from normal pregnancies and third trimester placentas from pregnancies with or without preeclampsia (PE) were used for the detection of KLF8 expression and correlating its levels with metalloproteinase 9 (MMP-9) expression. In addition, HTR8/SVneo cells were used to mimic the effects of an H/R environment on placentas to study KLF8 expression and trophoblast invasion. The KLF8 levels, MMP-9 levels, and trophoblast invasion were similarly altered; the levels peaked at 8 to 10 weeks of gestation and declined thereafter along with oxygen tension increased from hypoxia to normoxia during early pregnancy, decreased in third trimester placentas from PE pregnancies featured by repeated H/R and HTR8/SVneo cells exposed to H/R compared with the control. Moreover, a visible reduction in KLF8 immunoreactivity was present in the nuclei of cytotrophoblast cells in human villous tissues at 11 weeks, and partial cytoplasmic accumulation of KLF8 was observed in HTR8/SVneo cells treated with H/R. In conclusion, these findings strongly suggest that H/R reduces the expression and nuclear localization of KLF8 to inhibit the trophoblast invasion by downregulating MMP-9 levels. The KLF8 may play a vital role in the pathogenesis of PE as a novel oxygen tension sensor.

AKT as locus of cancer multidrug resistance and fragility

Complexity and robustness of cancer hypoxic microenvironment are supported by the robust signaling networks of autocrine and paracrine elements creating powerful interactome for multidrug resistance. These elements generate a positive feedback loops responsible for the extreme robustness and multidrug resistance in solid cancer, leukemia, myeloma, and lymphoma. Phosphorylated AKT is a cancer multidrug resistance locus. Targeting that locus by oxidant/antioxidant balance modulation, positive feedback loops are converted into negative feedback loops, leading to disappearance of multidrug resistance. This is a new principle for targeting cancer multidrug resistance by the locus chemotherapy inducing a phenomenon of loops conversion.

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.

AKT as locus of cancer positive feedback loops and extreme robustness

A positive feedback loops induce extreme robustness in metastatic cancer, relapsed leukemia, myeloma or lymphoma. The loops are generated by the signaling interactome networks of autocrine and paracrine elements from cancer hypoxic microenvironment. The elements of the networks are signaling proteins synthesized in hypoxic microenvironment such as the vascular endothelial growth factor, HIF-1α, hepatocyte growth factor, and molecules nitric oxide and H(2)O(2). The signals from upstream or rebound downstream pathways are amplified by the short or wide positive feedback loops, hyperstimulating AKT-inducing cancer extreme robustness. Targeting the phosphorylated AKT locus by an oxidant/antioxidant modulation induces collapse of positive feedback loops and establishment of negative feedback loops leading to stability of the system and disappearance of cancer extreme robustness. This is a new principle for the conversion of cancer positive loops into negative feedback loops by the locus chemotherapy.