Fucoidan from Undaria pinnatifida induces apoptosis in A549 human lung carcinoma cells

Etiology of lung carcinoma and treatment through medicinal plants, marine plants and green synthesized nanoparticles: A comprehensive review

Lung cancer, a leading global cause of mortality, poses a significant public health challenge primarily linked to tobacco use. While tobacco contributes to over 90% of cases, factors like dietary choices and radiation exposure also play a role. Despite potential benefits from early detection, cancer patients face hurdles, including drug resistance, chemotherapy side effects, high treatment costs, and limited healthcare access. Traditional medicinal plant knowledge has recently unveiled diverse cancer chemopreventive agents from terrestrial and marine sources. These phytochemicals regulate intricate molecular processes, influencing the immune system, apoptosis, cell cycle, proliferation, carcinogen elimination, and antioxidant levels. In pursuing cutting-edge strategies to combat the diverse forms of cancer, technological advancements have spurred innovative approaches. Researchers have focused on the green synthesis of metallic nanoparticles using plant metabolites. This method offers distinct advantages over conventional physical and chemical synthesis techniques, such as cost-effectiveness, biocompatibility, and energy efficiency. Metallic nanoparticles, through various pathways such as the generation of reactive oxygen species, modulation of enzyme activity, DNA fragmentation, disruption of signaling pathways, perturbation of cell membranes, and interference with mitochondrial function resulting in DNA damage, cell cycle arrest, and apoptosis, exhibit significant potential for preventive applications. Thus, the amalgamation of phytocompounds and metallic nanoparticles holds promise as a novel approach to lung cancer therapy. However, further refinements and advancements are necessary to enhance the environmentally friendly process of metallic nanoparticle synthesis.

Preparation and characterization of aspirin-fucoidan complex and its admirable antitumor activity on human non-small cell lung cancer cells

The purpose of this work is to prepare a novel acetylated derivative of Undaria pinnatifida fucoidan (UPFUC) with admirable antitumor activity. Fucoidan was first acetylated by acetylsalicylic acid (aspirin, ASA) to form the ASA-UPFUC complex. The antitumor efficacy results stated that ASA-UPFUC inhibited the proliferation of human non-small cell lung cancer A549 cells in a dose-dependent manner, with an IC50 value of 49.09 μg/mL, 50.20 % lower than that of UPFUC. Importantly, the acetylation process had no adverse effects on the backbone structure of UPFUC. Simultaneously, ASA-UPFUC demonstrated a larger charge density than UPFUC, leading to enhanced solubility, improved surface charge effects, and a greater potential for exerting biological activity. Consequently, ASA-UPFUC increased the formation of alkyl and hydrogen bonds with tumor necrosis factor related apoptosis-inducing ligand receptors DR4 and DR5, thereby effectively stimulating the generation of cellular reactive oxygen species, diminishing mitochondrial membrane potential, suppressing nuclear factor κB (NFκB) p65 phosphorylation, enhancing the contents of Bax and cleaved caspase 3, and reducing the level of Bcl-2. The collective effects ultimately triggered the mitochondrial apoptotic pathway, leading to apoptosis in A549 cells. The findings support the potential utilization of ASA-UPFUC as a novel dietary additive for human lung cancer chemoprevention.

Bioactive substances of cyanobacteria and microalgae: Sources, metabolism, and anticancer mechanism insights

Cyanobacteria and microalgae contain various phytochemicals, including bioactive components in the form of secondary metabolites, namely flavonoids, phenolic acids, terpenoids, and tannins, with remarkable anticancer effects. This review highlights the recent advances in bioactive compounds, with potential anticancer activity, produced by cyanobacteria and microalgae. Previous in vitro investigations showed that many of these bioactive compounds exhibit potent effects against different human cancer types, such as leukemia and breast cancers. Multiple mechanisms implicated in the antitumor effect of these compounds were elucidated, including their ability to target cellular, subcellular, and molecular checkpoints linked to cancer development and promotion. Recent findings have highlighted various mechanisms of action of bioactive compounds produced by cyanobacteria and microalgae, including induction of autophagy and apoptosis, inhibition of telomerase and protein kinases, as well as modulation of epigenetic modifications. In vivo investigations have demonstrated a potent anti-angiogenesis effect on solid tumors, as well as a reduction in tumor volume. Some of these compounds were examined in clinical investigations for certain types of cancers, making them potent candidates/scaffolds for antitumor drug development.

Antitumor and antioxidant activities of polysaccharides from the seaweed Durvillaea antarctica

The present study was carried out to determine the antitumor and antioxidant activities of the seaweed Durvillaea antarctica. Extraction and purification of polysaccharides from D. antarctica were performed. They were characterized by FT-IR and GC-MS, identifying isomers of arabinose, fucose, mannose, and galactose. The antioxidant capacity of polysaccharides was analyzed using the ABTS method (14.3 ± 0.5 μmol TE g-1 PS) and the DPPH method (21.82 ± 0.32 μmol TE g-1 PS). The antitumor capacity of polysaccharides was studied by MTT colorimetric assays in human leukemia, colon, breast, and lung cancer cell lines, obtaining the lowest IC50 in colon cancer (19.99 μg mL-1 ). In the line of healthy human gingival fibroblasts (HGF-1), an IC50 of 444.39 μg mL-1 was obtained. Flow cytometry in the HL60 cell line showed that polysaccharides at concentrations higher than IC50 inhibited cell proliferation, demonstrating a possible antitumor capacity in vitro. In the proteomic analysis with HGF-1, nine proteins involved in different biological processes were identified. In conclusion, polysaccharides from D. antarctica could be considered powerful nutraceuticals, mainly against colon cancer.

Fucoidan's Molecular Targets: A Comprehensive Review of Its Unique and Multiple Targets Accounting for Promising Bioactivities Supported by In Silico Studies

Fucoidan is a class of multifunctional polysaccharides derived from marine organisms. Its unique and diversified physicochemical and chemical properties have qualified them for potential and promising pharmacological uses in human diseases, including inflammation, tumors, immunity disorders, kidney diseases, and diabetes. Physicochemical and chemical properties are the main contributors to these bioactivities. The previous literature has attributed such activities to its ability to target key enzymes and receptors involved in potential disease pathways, either directly or indirectly, where the anionic sulfate ester groups are mainly involved in these interactions. These findings also confirm the advantageous pharmacological uses of sulfated versus non-sulfated polysaccharides. The current review shall highlight the molecular targets of fucoidans, especially enzymes, and the subsequent responses via either the upregulation or downregulation of mediators' expression in various tissue abnormalities. In addition, in silico studies will be applied to support the previous findings and show the significant contributors. The current review may help in understanding the molecular mechanisms of fucoidan. Also, the findings of this review may be utilized in the design of specific oligomers inspired by fucoidan with the purpose of treating life-threatening human diseases effectively.

Immunopotentiating Activity of Fucoidans and Relevance to Cancer Immunotherapy

Fucoidans, discovered in 1913, are fucose-rich sulfated polysaccharides extracted mainly from brown seaweed. These versatile and nontoxic marine-origin heteropolysaccharides have a wide range of favorable biological activities, including antitumor, immunomodulatory, antiviral, antithrombotic, anticoagulant, antithrombotic, antioxidant, and lipid-lowering activities. In the early 1980s, fucoidans were first recognized for their role in supporting the immune response and later, in the 1990s, their effects on immune potentiation began to emerge. In recent years, the understanding of the immunomodulatory effects of fucoidan has expanded significantly. The ability of fucoidan(s) to activate CTL-mediated cytotoxicity against cancer cells, strong antitumor property, and robust safety profile make fucoidans desirable for effective cancer immunotherapy. This review focusses on current progress and understanding of the immunopotentiation activity of various fucoidans, emphasizing their relevance to cancer immunotherapy. Here, we will discuss the action of fucoidans in different immune cells and review how fucoidans can be used as adjuvants in conjunction with immunotherapeutic products to improve cancer treatment and clinical outcome. Some key rationales for the possible combination of fucoidans with immunotherapy will be discussed. An update is provided on human clinical studies and available registered cancer clinical trials using fucoidans while highlighting future prospects and challenges.

Seaweeds in the Oncology Arena: Anti-Cancer Potential of Fucoidan as a Drug—A Review

Marine natural products are a discerning arena to search for the future generation of medications to treat a spectrum of ailments. Meanwhile, cancer is becoming more ubiquitous over the world, and the likelihood of dying from it is rising. Surgery, radiation, and chemotherapy are the mainstays of cancer treatment worldwide, but their extensive side effects limit their curative effect. The quest for low-toxicity marine drugs to prevent and treat cancer is one of the current research priorities of researchers. Fucoidan, an algal sulfated polysaccharide, is a potent therapeutic lead candidate against cancer, signifying that far more research is needed. Fucoidan is a versatile, nontoxic marine-origin heteropolysaccharide that has received much attention due to its beneficial biological properties and safety. Fucoidan has been demonstrated to exhibit a variety of conventional bioactivities, such as antiviral, antioxidant, and immune-modulatory characteristics, and anticancer activity against a wide range of malignancies has also recently been discovered. Fucoidan inhibits tumorigenesis by prompting cell cycle arrest and apoptosis, blocking metastasis and angiogenesis, and modulating physiological signaling molecules. This review compiles the molecular and cellular aspects, immunomodulatory and anticancer actions of fucoidan as a natural marine anticancer agent. Specific fucoidan and membranaceous polysaccharides from Ecklonia cava, Laminaria japonica, Fucus vesiculosus, Astragalus, Ascophyllum nodosum, Codium fragile serving as potential anticancer marine drugs are discussed in this review.

Impacts of Oxidative Stress and PI3K/AKT/mTOR on Metabolism and the Future Direction of Investigating Fucoidan-Modulated Metabolism

The critical factors for regulating cancer metabolism are oxidative stress and phosphoinositide-3-kinase/AKT serine-threonine kinase/mechanistic target of the rapamycin kinase (PI3K/AKT/mTOR). However, the metabolic impacts of oxidative stress and PI3K/AKT/mTOR on individual mechanisms such as glycolysis (Warburg effect), pentose phosphate pathway (PPP), fatty acid synthesis, tricarboxylic acid cycle (TCA) cycle, glutaminolysis, and oxidative phosphorylation (OXPHOS) are complicated. Therefore, this review summarizes the individual and interacting functions of oxidative stress and PI3K/AKT/mTOR on metabolism. Moreover, natural products providing oxidative stress and PI3K/AKT/mTOR modulating effects have anticancer potential. Using the example of brown algae-derived fucoidan, the roles of oxidative stress and PI3K/AKT/mTOR were summarized, although their potential functions within diverse metabolisms were rarely investigated. We propose a potential application that fucoidan may regulate oxidative stress and PI3K/AKT/mTOR signaling to modulate their associated metabolic regulations. This review sheds light on understanding the impacts of oxidative stress and PI3K/AKT/mTOR on metabolism and the future direction of metabolism-based cancer therapy of fucoidan.

Recent research advances in polysaccharides from Undaria pinnatifida: Isolation, structures, bioactivities, and applications

Undaria pinnatifida, one of the most widespread seafood consumed in China and many other nations, has been traditionally utilized as an effective therapeutically active substance for edema, phlegm elimination and diuresis, and detumescence for more than 2000 years. Numerous studies have found that polysaccharides of U. pinnatifida play an indispensable role in the nutritional and medicinal value. The water extraction and alcohol precipitation method are the most used method. More than 40 U. pinnatifida polysaccharides (UPPs) were successfully isolated and purified from U. pinnatifida, whereas only few of them were well characterized. Pharmacological studies have shown that UPPs have high-order structural features and multiple biological activities, including anti-tumor, antidiabetic, immunomodulatory, antiviral, anti-inflammatory, antioxidant, anticoagulating, antithrombosis, antihypertension, antibacterial, and renoprotection. In addition, the structural characteristics of UPPs are closely related to their biological activity. In this review, the extraction and purification methods, structural characteristics, biological activities, clinical settings, toxicities, structure-activity relationships and industrial application of UPPs are comprehensively summarized. The structural characteristics and biological activities as well as the underlying molecular mechanisms of UPPs were also outlined. Furthermore, the clinical settings and structure-activity functions of UPPs were highlighted. Some research perspectives and challenges in the study of UPPs were also proposed.

A Transcriptome Sequencing Study on Genome-Wide Gene Expression Differences of Lung Cancer Cells Modulated by Fucoidan

Fucoidan has received increasing attention in anti-(lung) tumors. However, the effect of fucoidan on the gene changes of lung cancer cells (LCCs) has not been examined systematically. Herein, we investigate the effect of fucoidan on the phenotypes of LCCs and their gene expression by transcriptome sequencing analysis. The phenotypes of LCCs are significantly inhibited by fucoidan. Importantly, compared to LCCs, 1 mg/ml fucoidan has no effect on the phenotypes of normal cells. Further, 6,930 differentially expressed genes (DEGs) in the transcriptome of LCCs (3,501 up-regulated and 3,429 down-regulated genes) are detected via RNA-sequencing between the fucoidan and control groups. Gene Ontology analysis confirms that DEGs are reflected in DNA replication, cell-substrate junction, regulation of cell cycle phase transition, apoptosis, focal adhesion, cadherin binding, and cell adhesion molecule binding. Thus, our findings on the transcriptomic level highlight the therapeutic potential of fucoidan for lung cancer treatment.

An Overview of Potential Seaweed-Derived Bioactive Compounds for Pharmaceutical Applications

Nowadays, seaweeds are widely involved in biotechnological applications. Due to the variety of bioactive compounds in their composition, species of phylum Ochrophyta, class Phaeophyceae, phylum Rhodophyta and Chlorophyta are valuable for the food, cosmetic, pharmaceutical and nutraceutical industries. Seaweeds have been consumed as whole food since ancient times and used to treat several diseases, even though the mechanisms of action were unknown. During the last decades, research has demonstrated that those unique compounds express beneficial properties for human health. Each compound has peculiar properties (e.g., antioxidant, antimicrobial, antiviral activities, etc.) that can be exploited to enhance human health. Seaweed's extracted polysaccharides are already involved in the pharmaceutical industry, with the aim of replacing synthetic compounds with components of natural origin. This review aims at a better understanding of the recent uses of algae in drug development, with the scope of replacing synthetic compounds and the multiple biotechnological applications that make up seaweed's potential in industrial companies. Further research is needed to better understand the mechanisms of action of seaweed's compounds and to embrace the use of seaweeds in pharmaceutical companies and other applications, with the final scope being to produce sustainable and healthier products.

Phytosterols in Seaweeds: An Overview on Biosynthesis to Biomedical Applications

Seaweed extracts are considered effective therapeutic alternatives to synthetic anticancer, antioxidant, and antimicrobial agents, owing to their availability, low cost, greater efficacy, eco-friendliness, and non-toxic nature. Since the bioactive constituents of seaweed, in particular, phytosterols, possess plenty of medicinal benefits over other conventional pharmaceutical agents, they have been extensively evaluated for many years. Fortunately, recent advances in phytosterol-based research have begun to unravel the evidence concerning these important processes and to endow the field with the understanding and identification of the potential contributions of seaweed-steroidal molecules that can be used as chemotherapeutic drugs. Despite the myriad of research interests in phytosterols, there is an immense need to fill the void with an up-to-date literature survey elucidating their biosynthesis, pharmacological effects, and other biomedical applications. Hence, in the present review, we summarize studies dealing with several types of seaweed to provide a comprehensive overview of the structural determination of several phytosterol molecules, their properties, biosynthetic pathways, and mechanisms of action, along with their health benefits, which could significantly contribute to the development of novel drugs and functional foods.

Enhancement of Immune Checkpoint Inhibitor-Mediated Anti-Cancer Immunity by Intranasal Treatment of Ecklonia cava Fucoidan against Metastatic Lung Cancer

Although fucoidan, a well-studied seaweed-extracted polysaccharide, has shown immune stimulatory effects that elicit anticancer immunity, mucosal adjuvant effects via intranasal administration have not been studied. In this study, the effect of Ecklonia cava-extracted fucoidan (ECF) on the induction of anti-cancer immunity in the lung was examined by intranasal administration. In C57BL/6 and BALB/c mice, intranasal administration of ECF promoted the activation of dendritic cells (DCs), natural killer (NK) cells, and T cells in the mediastinal lymph node (mLN). The ECF-induced NK and T cell activation was mediated by DCs. In addition, intranasal injection with ECF enhanced the anti-PD-L1 antibody-mediated anti-cancer activities against B16 melanoma and CT-26 carcinoma tumor growth in the lungs, which were required cytotoxic T lymphocytes and NK cells. Thus, these data demonstrated that ECF functioned as a mucosal adjuvant that enhanced the immunotherapeutic effect of immune checkpoint inhibitors against metastatic lung cancer.

The Therapeutic Potential of the Anticancer Activity of Fucoidan: Current Advances and Hurdles

Several types of cancers share cellular and molecular behaviors. Although many chemotherapy drugs have been designed to weaken the defenses of cancer cells, these drugs may also have cytotoxic effects on healthy tissues. Fucoidan, a sulfated fucose-based polysaccharide from brown algae, has gained much attention as an antitumor drug owing to its anticancer effects against multiple cancer types. Among the anticancer mechanisms of fucoidan are cell cycle arrest, apoptosis evocation, and stimulation of cytotoxic natural killer cells and macrophages. Fucoidan also protects against toxicity associated with chemotherapeutic drugs and radiation-induced damage. The synergistic effect of fucoidan with existing anticancer drugs has prompted researchers to explore its therapeutic potential. This review compiles the mechanisms through which fucoidan slows tumor growth, kills cancer cells, and interacts with cancer chemotherapy drugs. The obstacles involved in developing fucoidan as an anticancer agent are also discussed in this review.

Fucoidan from Laminaria japonica Inhibits Expression of GLUT9 and URAT1 via PI3K/Akt, JNK and NF-κB Pathways in Uric Acid-Exposed HK-2 Cells

This work aimed to investigate the effect of fucoidan (FPS) on urate transporters induced by uric acid (UA). The results showed that UA stimulated the expression of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1) in HK-2 cells, and FPS could reverse the effect. Moreover, UA could activate NF-κB, JNK and PI3K/Akt pathways, but both pathway inhibitors and FPS inhibited the UA-induced activation of these three pathways. These data suggested that FPS effectively inhibited the expression induction of reabsorption transporters URAT1 and GLUT9 by UA, through repressing the activation of NF-κB, JNK and PI3K/Akt signal pathways in HK-2 cells. The in vitro research findings support the in vivo results that FPS reduces serum uric acid content in hyperuricemia mice and rats through inhibiting the expression of URAT1 and GLUT9 in renal tubular epithelial cells. This study provides a theoretical basis for the application of FPS in the treatment of hyperuricemia.

Fucoidan Structure and Its Impact on Glucose Metabolism: Implications for Diabetes and Cancer Therapy

Fucoidans are complex polysaccharides derived from brown seaweeds which consist of considerable proportions of L-fucose and other monosaccharides, and sulphated ester residues. The search for novel and natural bioproduct drugs (due to toxicity issues associated with chemotherapeutics) has led to the extensive study of fucoidan due to reports of it having several bioactive characteristics. Among other fucoidan bioactivities, antidiabetic and anticancer properties have received the most research attention in the past decade. However, the elucidation of the fucoidan structure and its biological activity is still vague. In addition, research has suggested that there is a link between diabetes and cancer; however, limited data exist where dual chemotherapeutic efforts are elucidated. This review provides an overview of glucose metabolism, which is the central process involved in the progression of both diseases. We also highlight potential therapeutic targets and show the relevance of fucoidan and its derivatives as a candidate for both cancer and diabetes therapy.

Bioactive Compounds of Seaweeds and Their Effects on Certain Types of Cancer

Cancer is considered as one of the major health problems worldwide. So far, no completely effective method has been found for cancer treatment. Therefore, the rise of using natural products has been proposed as an alternative therapy in this regard. For many years, the seaweed has been a source of many functional bioactive compounds including polysaccharides, polyphenols, pigments, terpenes, and many others. These compounds have shown many bioactivities including anticancer activity against different kinds of cancer. Bioactive compounds obtained from the seaweed have been demonstrated to cause apoptosis in cancer cells and trigger cell cycle arrest with low cytotoxicity against normal cells. In this review, it was attempted to shed light on the anticancer activity of some seaweed-derived bioactive compounds.

Anticancer and Immunomodulatory Effects of Polysaccharides

Cancer is one of the leading causes of death and one of the most important public health problems in the world. And every year, millions of new cancers and hundreds of thousands of cancer-related deaths are reported worldwide. In recent decades, a number of biologically active polysaccharides and polysaccharide-protein complexes have been isolated from plants, lichen, algae, yeast, fungi and mushroom, and due to their antitumor and immunomodulatory properties, these compounds have received considerable attention. Overall, the two key mechanisms by which polysaccharides act on tumor cells are direct action (inhibition of cancer cell growth and induction of programmed cell death/apoptosis) and indirect action (stimulation of immunity). Immunosuppressive effects are recognizable in both cancer patients and tumor bearing animals, suggesting that the immune system plays an important role in the immune surveillance of cancer cells. Thus, enhancement of the host immune response has been evaluated as a possible way of inhibiting tumor growth without damaging the host. In addition to their therapeutic and prophylactic properties, the polysaccharides are effective and less toxic than chemotherapy. The anticancer activity and immunomodulatory effects of most polysaccharides have shown the promising and real potential for the benefits of human health.

A review on fucoidan antitumor strategies: From a biological active agent to a structural component of fucoidan-based systems

Due to the severe side-effects and the toxicity to healthy tissues, cancer treatments based in chemotherapy have not fully achieved the desire outcomes so far. The use of natural compound may be of great value to develop better tolerated therapies. Fucoidan is a marine sulfated polysaccharide extracted from brown algae that, besides other biological activities, has been reported to present interesting anti-cancer potential. This review briefly introduces fucoidan chemical structure, physicochemical properties and the above-mentioned biological feature. Fucoidan usage as soluble agent presents promising results herein described for different types of cancer. Trying to enhance and optimize fucoidan usage in the cancer field, different systems, namely drug delivery, have been recently developed to target different types of cancers. This aspect will be presented in detail, highlighting the role of fucoidan on their reported or envisaged performance.

Degradation of Sargassum crassifolium Fucoidan by Ascorbic Acid and Hydrogen Peroxide, and Compositional, Structural, and In Vitro Anti-Lung Cancer Analyses of the Degradation Products

Fucoidans possess multiple biological functions including anti-cancer activity. Moreover, low-molecular-weight fucoidans are reported to possess more bioactivities than native fucoidans. In the present study, a native fucoidan (SC) was extracted from Sargassum crassifolium pretreated by single-screw extrusion, and three degraded fucoidans, namely, SCA (degradation of SC by ascorbic acid), SCH (degradation of SC by hydrogen peroxide), and SCAH (degradation of SC by ascorbic acid + hydrogen peroxide), were produced. The extrusion pretreatment can increase the extraction yield of fucoidan by approximately 4.2-fold as compared to the non-extruded sample. Among SC, SCA, SCH, and SCAH, the chemical compositions varied but structural features were similar. SC, SCA, SCH, and SCAH showed apoptotic effects on human lung carcinoma A-549 cells, as illustrated by loss of mitochondrial membrane potential (MMP), decreased B-cell leukemia-2 (Bcl-2) expression, increased cytochrome c release, increased active caspase-9 and -3, and increased late apoptosis of A-549 cells. In general, SCA was found to exhibit high cytotoxicity to A-549 cells and a strong ability to suppress Bcl-2 expression. SCA also showed high efficacy to induce cytochrome c release, activate caspase-9 and -3, and promote late apoptosis of A-549 cells. Therefore, our data suggest that SCA could have an adjuvant therapeutic potential in the treatment of lung cancer. Additionally, we explored that the Akt/mammalian target of rapamycin (mTOR) signaling pathway is involved in SC-, SCA-, SCH-, and SCAH-induced apoptosis of A-549 cells.

Protective Effects of Fucoidan Isolated from Celluclast-Assisted Extract of Undaria pinnatifida Sporophylls against AAPH-Induced Oxidative Stress In Vitro and In Vivo Zebrafish Model

Fucoidan is a fucose-enriched polysaccharide, obtained from brown algae, with demonstrated antioxidant properties. However, traditional extraction methods using water or chemical-based extraction methods have reduced yield and produced hazardous by-products. In this study, we isolated fucoidan at a high yield using enzyme-assisted extraction; the Celluclast enzyme assisted extract of Undaria pinnatifida sporophylls (FCUS). To examine the antioxidant properties of FCUS, oxidative stress was induced with 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAPH) in Vero cells and zebrafish model. FCUS was composed of 30.4% sulfate and 52.3% fucose. Pre-treatment of Vero cells with FCUS dose dependently inhibited AAPH-induced reactive oxygen species (ROS) production. Moreover, FCUS remarkably reduced cell death, ROS generation, and lipid peroxidation production in zebrafish larvae. Overall, these findings indicate that the sulfate-rich fucoidan of FCUS, obtained with an eco-friendly process, could be implemented as a beneficial antioxidant agent in the functional food industry.

The anti-cancer effects of fucoidan: a review of both in vivo and in vitro investigations

Fucoidan is a kind of the polysaccharide, which comes from brown algae and comprises of sulfated fucose residues. It has shown a large range of biological activities in basic researches, including many elements like anti-inflammatory, anti-cancer, anti-viral, anti-oxidation, anticoagulant, antithrombotic, anti-angiogenic and anti-Helicobacter pylori, etc. Cancer is a multifactorial disease of multiple causes. Most of the current chemotherapy drugs for cancer therapy are projected to eliminate the ordinary deregulation mechanisms in cancer cells. Plenty of wholesome tissues, however, are also influenced by these chemical cytotoxic effects. Existing researches have demonstrated that fucoidan can directly exert the anti-cancer actions through cell cycle arrest, induction of apoptosis, etc., and can also indirectly kill cancer cells by activating natural killer cells, macrophages, etc. Fucoidan is used as a new anti-tumor drug or as an adjuvant in combination with an anti-tumor drug because of its high biological activity, wide source, low resistance to drug resistance and low side effects. This paper reviews the mechanism by which fucoidan can eliminate tumor cells, delay tumor growth and synergize with anticancer chemotherapy drugs in vitro, in vivo and in clinical trials.

Algae-Derived Bioactive Compounds with Anti-Lung Cancer Potential

Lung cancer is one of the major causes of death worldwide. Natural molecules with anti-lung cancer potential are of a great interest and considered as very promising alternative to substitute or enhance the efficiency of the conventional drugs. Recently, algae as source of high value-added compounds are considered as very promising source of these bioactive molecules. These are secondary metabolites that consist mainly of derivatives of peptides, carbohydrates, and lipids with various structures. Accordingly, various mechanisms by which different algae molecules demonstrate attenuation of tumor angiogenesis were stated and discussed. The mode of action of the algae bioactives is closely related to their nature and chemical structure. Furthermore, this literature review considers the synergistic effect between microalgae bioactives and conventional drugs and discuss the economic feasibility of producing microalgae bioactives at large scale to conclude with some future perspectives related to algae-based drug discovery.

Fucoidan from marine brown algae attenuates pancreatic cancer progression by regulating p53 - NFκB crosstalk

Poor pancreatic cancer (PC) prognosis has been attributed to its resistance to apoptosis and propensity for early systemic dissemination. Existing therapeutic strategies are often circumvented by the molecular crosstalk between cell-signalling pathways. p53 is mutated in more than 50% of PC and NFκB is constitutively activated in therapy-resistant residual disease; these mutations and activations account for the avoidance of cell death and metastasis. Recently, we demonstrated the anti-PC potential of fucoidan extract from marine brown alga, Turbinaria conoides (J. Agardh) Kützing (Sargassaceae). In this study, we aimed to characterize the active fractions of fucoidan extract to identify their select anti-PC efficacy, and to define the mechanism(s) involved. Five fractions of fucoidan isolated by ion exchange chromatography were tested for their potential in genetically diverse human PC cell lines. All fractions exerted significant dose-dependent and time-dependent regulation of cell survival. Fucoidans induced apoptosis, activated caspase -3, -8 and -9, and cleaved Poly ADP ribose polymerase (PARP). Pathway-specific transcriptional analysis recognized inhibition of 57 and 38 nuclear factor κB (NFκB) pathway molecules with fucoidan-F5 in MiaPaCa-2 and Panc-1 cells, respectively. In addition, fucoidan-F5 inhibited both the constitutive and Tumor necrosis factor-α (TNFα)-mediated NFκB DNA-binding activity in PC cells. Upregulation of cytoplasmic IκB levels and significant reduction of NFκB-dependent luciferase activity further substantiate the inhibitory potential of seaweed fucoidans on NFκB. Moreover, fucoidan(s) treatment increased cellular p53 in PC cells and reverted NFκB forced-expression-related p53 reduction. The results suggest that fucoidan regulates PC progression and that fucoidans may target p53-NFκB crosstalk and dictate apoptosis in PC cells.

Selective Suppression of Cell Growth and Programmed Cell Death-Ligand 1 Expression in HT1080 Fibrosarcoma Cells by Low Molecular Weight Fucoidan Extract

Low molecular weight fucoidan extract (LMF), prepared by an abalone glycosidase digestion of a crude fucoidan extracted from Cladosiphon novae-caledoniae Kylin, exhibits various biological activities, including anticancer effect. Various cancers express programmed cell death-ligand 1 (PD-L1), which is known to play a significant role in evasion of the host immune surveillance system. PD-L1 is also expressed in many types of normal cells for self-protection. Previous research has revealed that selective inhibition of PD-L1 expressed in cancer cells is critical for successful cancer eradication. In the present study, we analyzed whether LMF could regulate PD-L1 expression in HT1080 fibrosarcoma cells. Our results demonstrated that LMF suppressed PD-L1/PD-L2 expression and the growth of HT1080 cancer cells and had no effect on the growth of normal TIG-1 cells. Thus, LMF differentially regulates PD-L1 expression in normal and cancer cells and could serve as an alternative complementary agent for treatment of cancers with high PD-L1 expression.

6,7-Dihydroxy-2-(4'-hydroxyphenyl)naphthalene induces HCT116 cell apoptosis through activation of endoplasmic reticulum stress and the extrinsic apoptotic pathway

Background

Colorectal cancer is the third leading cause of cancer-related deaths worldwide, and therefore, the development of novel drugs for its prevention and therapy are urgently required. This study aimed to determine the molecular mechanism of 6,7-dihydroxy-2-(4′-hydroxyphenyl) naphthalene (PNAP-6)-induced cytotoxicity in human colorectal cancer (HCT116) cells.

Methods

The effects of 2-phenylnaphthalene derivatives on HCT116 cell growth and viability were assessed by MTT assays. The mechanisms involved in the regulation of the extrinsic apoptosis and endoplasmic reticulum (ER) stress pathways by PNAP-6 were analyzed by annexin-V/propidium iodide flow cytometric analysis, Hoechst 33342 fluorescent staining, and Western blotting.

Results

PNAP-6 was shown to have an IC₅₀ value 15.20 μM. It induced G₂/M phase arrest in HCT116 cells, associated with a marked decrease in cyclin B and CDK1 protein expression and increased caspase activation, PARP cleavage, chromatin condensation, and sub-G₁ apoptosis. Moreover, we found that the apoptotic effects of PNAP-6 proceeded through extrinsic apoptosis and ER stress pathways, by increasing the expression of Fas protein and ER stress markers, including PERK, ATF4, CHOP, p-IRE1α, and XBP-1s.

Conclusion

These results suggest that 2-phenylnaphthalene derivatives, such as PNAP-6, have potential as new treatments for colorectal cancer.

Biological Activities of Fucoidan and the Factors Mediating Its Therapeutic Effects: A Review of Recent Studies

The marine acid polysaccharide fucoidan has attracted attention from both the food and pharmaceutical industries due to its promising therapeutic effects. Fucoidan is a polysaccharide that mainly consists of L-fucose and sulphate groups. Its excellent biological function is attributed to its unique biological structure. Classical activities include antitumor, antioxidant, anticoagulant, antithrombotic, immunoregulatory, antiviral and anti-inflammatory effects. More recently, fucoidan has been shown to alleviate metabolic syndrome, protect the gastrointestinal tract, benefit angiogenesis and bone health. This review focuses on the progress in our understanding of the biological activities of fucoidan, highlighting its benefits for the treatment of human disease. We hope that this review can provide some theoretical basis and inspiration for the product development of fucoidan.

Comparison of structure and in vitro anticancer activity of native and modified fucoidans from Sargassum feldmannii and S. duplicatum

Fucoidans are valuable biologically active polysaccharides of brown algae. The aim of this study was to investigate the structure of fucoidan from Sargassum feldmannii and the anticancer effects of native and modified polysaccharides from S. feldmannii and S. duplicatum. The structure of sulfated (25.3%) galactofucan SfF2 (Fuc/Gal = 72/28 mol%) from S. feldmannii was investigated by NMR spectroscopy of desulfated derivative and mass spectrometry of fucoidan fragments labelled with 18O. SfF2 was shown to contain the main chain from 1,3-linked α-l-fucopyranose and β-d-galactopyranose residues with fucose branches at C4 and C6 of galactose residues and C2 of fucose residues. The following fragments were also identified in SfF2: Fuc-(1,4)-Fuc, Gal-(1,3)-Gal, and Gal-(1,4)-Gal. The sulfate groups occupied positions C2, C3, and C4 of fucose residues and C2, C3, C4, and C6 of galactose residues. The galactofucans from S. feldmannii, S. duplicatum, and their derivatives exhibited no cytotoxicity in vitro. The native and deacetylated fucoidans (200 μg/mL) inhibited colony formation of human colon cancer cells (DLD-1, HT-29, and HCT-116). Both desulfated fucoidans possessed weak anticancer activity.

New Drugs from the Sea: Pro-Apoptotic Activity of Sponges and Algae Derived Compounds

Natural compounds derived from marine organisms exhibit a wide variety of biological activities. Over the last decades, a great interest has been focused on the anti-tumour role of sponges and algae that constitute the major source of these bioactive metabolites. A substantial number of chemically different structures from different species have demonstrated inhibition of tumour growth and progression by inducing apoptosis in several types of human cancer. The molecular mechanisms by which marine natural products activate apoptosis mainly include (1) a dysregulation of the mitochondrial pathway; (2) the activation of caspases; and/or (3) increase of death signals through transmembrane death receptors. This great variety of mechanisms of action may help to overcome the multitude of resistances exhibited by different tumour specimens. Therefore, products from marine organisms and their synthetic derivates might represent promising sources for new anticancer drugs, both as single agents or as co-adjuvants with other chemotherapeutics. This review will focus on some selected bioactive molecules from sponges and algae with pro-apoptotic potential in tumour cells.

Undaria pinnatifida a Rich Marine Reservoir of Nutritional and Pharmacological Potential: Insights into Growth Signaling and Apoptosis Mechanisms in Cancer

Seaweeds are an important part of diet consumed in a different part of the world such as New Zealand, Ireland, Wales, and Asian countries including Korea, China, and Japan. In addition, seaweed is nutritious sources possessing health improving effects and therapeutic potential. Recently, one of the widely eaten seaweed species Undaria pinnatifida (U. pinnatifida) has got much attention because of its pharmacological properties for the prevention of various ailments, including cancer, inflammation, and other diseases. It is rich in all essential amino acids, physiologically significant fatty acids, vitamins, minerals, and has a variety of bioactive constituents which include fucoidan, carotenoids, and fucoxanthin. The present study reviews the nutritional aspects, key bioactivities specifically focusing on anticancer potential along with apoptosis and growth signaling mechanisms of U. pinnatifida or its constituents. It exhibited anticancer effects both in vitro and in vivo studies in a variety of experimental models. Due to a variety of pharmacological properties of U. pinnatifida can not only fulfilling nutritional necessities, but it can be used for treating, curing and preventing cancer.

Fucoidan-coated CuS nanoparticles for chemo-and photothermal therapy against cancer

In advanced cancer therapy, the combinational therapeutic effect of photothermal therapy (PTT) using near-infrared (NIR) light-responsive nanoparticles (NPs) and anti-cancer drug delivery-mediated chemotherapy has been widely applied. In the present study, using a facile, low-cost, and solution-based method, we developed and synthesized fucoidan, a natural polymer isolated from seaweed that has demonstrated anti-cancer effect, and coated NPs with it as an ideal candidate in chemo-photothermal therapy against cancer cells. Fucoidan-coated copper sulfide nanoparticles (F-CuS) act not only as a nanocarrier to enhance the intracellular delivery of fucoidan but also as a photothermal agent to effectively ablate different cancer cells (e.g., HeLa, A549, and K562), both in vitro and in vivo, with the induction of apoptosis under 808 nm diode laser irradiation. These results point to the potential usage of F-CuS in treating human cancer.

The Identification of a SIRT6 Activator from Brown Algae Fucus distichus

Brown seaweeds contain many bioactive compounds, including polyphenols, polysaccharides, fucosterol, and fucoxantin. These compounds have several biological activities, including anti-inflammatory, hepatoprotective, anti-tumor, anti-hypertensive, and anti-diabetic activity, although in most cases their mechanisms of action are not understood. In this study, extracts generated from five brown algae (Fucus dichitus, Fucus vesiculosus (Linnaeus), Cytoseira tamariscofolia, Cytoseira nodacaulis, Alaria esculenta) were tested for their ability to activate SIRT6 resulting in H3K9 deacetylation. Three of the five macroalgal extracts caused a significant increase of H3K9 deacetylation, and the effect was most pronounced for F. dichitus. The compound responsible for this in vitro activity was identified by mass spectrometry as fucoidan.

Protective Role of Fucoidan in Cerebral Ischemia-Reperfusion Injury through Inhibition of MAPK Signaling Pathway

Fucoidan has been reported to exhibit various beneficial activities ranging from to antivirus and anticancer properties. However, little information is available about the effects of fucoidan on cerebral ischemia-reperfusion injury (IRI). Our study aimed to explore the effects of fucoidan on cerebral IRI, as well as the underlying mechanisms. Sprague-Dawley (SD) rats were randomly subjected to four groups: Sham, IRI+saline (IRI+S), IRI+80 mg/kg fucoidan (IRI+F80), and IRI+160 mg/kg fucoidan (IRI+F160). Fucoidan (80 mg/kg or 160 mg/kg) was intraperitoneally injected from 7 days before the rats were induced to cerebral IRI model with middle cerebral artery occlusion (MCAO) method. At 24 h after reperfusion, neurological deficits and the total infarct volume were determined. The levels of inflammation-associated cytokines (interleukin (IL)-1β, IL-6, myeloperoxidase (MPO), and tumor necrosis factor (TNF)-α), oxidative stress-related proteins (malondialdehyde (MDA) and superoxide dismutase (SOD)) in the ischemic brain were measured by enzyme-linked immunosorbent assay (ELISA). Besides, the levels of apoptosis-related proteins (p-53, Bax, and B-cell lymphoma (Bcl)-2) and mitogen-activated protein kinase (MAPK) pathway (phosphorylation-extracellular signalregulated kinase (p-ERK), p-c-Jun N-terminal kinase (JNK), and p-p38) were measured. Results showed that administration of fucoidan significantly reduced the neurological deficits and infarct volume compared to the IRI+S group in a dose-dependent manner. Also, fucoidan statistically decreased the levels of inflammation-associated cytokines, and oxidative stress-related proteins, inhibited apoptosis, and suppressed the MAPK pathway. So, Fucoidan plays a protective role in cerebral IRI might be by inhibition of MAPK pathway.

Phytochemical profiling of Turbinaria ornata and its antioxidant and anti-proliferative effects

Objectives

To analyse the phytochemicals and evaluate the antioxidant and anti-proliferative ability of Turbinaria ornata (Turner) J. Agardh, 1848.

Methods

A phytochemical analysis of the T. ornata-hexane extract (To-HE) and T. ornata-aqueous extract (To-AE) was performed. T. ornata extracts were analysed by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). The antioxidant properties of To-HE and To-AE were determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) and ferric ion reducing power (FRAP) assays. In addition, the in vitro anti-proliferative properties of To-HE and To-AE were assessed in kidney epithelial cells from the African green monkey (Vero) and in adenocarcinomic human alveolar basal epithelial cells (A549) using the MTT (3-(4,5-dimethylthiazol- 2yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole) assay.

Results

The phytochemical screening of T. ornata revealed the presence of saponin, alkaloids, amino acids, fixed oil and fat and phenolic compounds (tannins, flavonoids and total phenol). A higher antioxidant ability was found in To-HE than in To-AE. The anti-proliferative efficacy values (μg/mL) of To-HE and To-AE for A549 and Vero cells were 62.91 and 93.00 and 72.64 and 106.6, respectively. The FTIR analysis revealed the presence of functional groups such as alcohols, amides, aromatics, amines, alkyl halides, alkynes, alkanes and carboxylic acids. The GC-MS analysis of To-HE revealed the presence of 13 active compounds.

Conclusion

Owing to its recorded anti-proliferative effect, further pharmaceutical studies on the development of this anticancer drug are merited.

Fucoidan Induces ROS-Dependent Apoptosis in 5637 Human Bladder Cancer Cells by Downregulating Telomerase Activity via Inactivation of the PI3K/Akt Signaling Pathway

Preclinical Research Fucoidan, a sulfated polysaccharide, is a compound found in various species of seaweed that has anti-viral, anti-bacterial, anti-oxidant, anti-inflammatory, and immunomodulatory activities; however, the underlying relationship between apoptosis and anti-telomerase activity has not been investigated. Here, we report that fucoidan-induced apoptosis in 5637 human bladder cancer cells was associated with an increase in the Bax/Bcl-2 ratio, the dissipation of the mitochondrial membrane potential (MMP, Δψm), and cytosolic release of cytochrome c from the mitochondria. Under the same experimental conditions, fucoidan-treatment decreased hTERT (human telomerase reverse transcriptase) expression and the transcription factors, c-myc and Sp1. This was accompanied by decreased telomerase activity. Fucoidan-treatment also suppressed activation of the PI3K/Akt signaling pathway. Inhibition of PI3K/Akt signaling enhanced fucoidan-induced apoptosis and anti-telomerase activity. Meanwhile, fucoidan treatment increased the generation of intracellular ROS, whereas the over-elimination of ROS by N-acetylcysteine, an anti-oxidant, attenuated fucoidan-induced apoptosis, inhibition of hTERT, c-myc, and Sp1 expression, and reversed fucoidan-induced inactivation of the PI3K/Akt signaling pathway. Collectively, these data indicate that the induction of apoptosis and the inhibition of telomerase activity by fucoidan are mediated via ROS-dependent inactivation of the PI3K/Akt pathway. Drug Dev Res 78 : 37-48, 2017.   © 2016 Wiley Periodicals, Inc.

A review about the development of fucoidan in antitumor activity: Progress and challenges

Fucoidan is composed of l-fucose, sulfate groups and one or more small proportions of d-xylose, d-mannose, d-galactose, l-rhamnose, arabinose, glucose, d-glucuronic acid and acetyl groups in different kinds of brown seaweeds. Many reports have demonstrated that fucoidan has antitumor activities on various cancers. However, until now, few reviews have discussed the antitumor activity of fucoidan and few reports have summarized detailed molecular mechanisms of its actions and antitumor challenges of fucoidan specially. In this review, the antitumor signaling pathway mechanisms related to fucoidan are elucidated as much detail as possible. Besides, the factors affecting the anticancer effects of fucoidan, the structural characteristics of fucoidan with anticancer activities and the challenges for the further development of fucoidan are also summarized and evaluated. The existing similar and different conclusions are summarized in an attempt to provide guidelines to help further research, and finally contribute to go into market as chemotherapeumtics.

Fucoidans in Nanomedicine

Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine as imaging agents, drug carriers or for their intrinsic properties are reviewed here after a short presentation of the main structural data and biological properties of fucoidans. The origin and the physicochemical specifications of fucoidans are summarized in order to discuss the strategy of fucoidan-containing nanosystems in Human health. Currently, there is a need for reproducible, well characterized fucoidan fractions to ensure significant progress.

Fucoidan Suppresses the Growth of Human Acute Promyelocytic Leukemia Cells In Vitro and In Vivo

Fucoidan, a natural component of seaweeds, is reported to have immunomodulatory and anti-tumor effects. The mechanisms underpinning these activities remain poorly understood. In this study, the cytotoxicity and anti-tumor activities of fucoidan were investigated in acute myeloid leukemia (AML) cells. The human AML cell lines NB4, KG1a, HL60, and K562 were treated with fucoidan and cell cycle, cell proliferation, and expression of apoptotic pathways molecules were analyzed. Fucoidan suppressed the proliferation and induced apoptosis through the intrinsic and extrinsic pathways in the acute promyelocytic leukemia (APL) cell lines NB4 and HL60, but not in KG1a and K562 cells. In NB4 cells, apoptosis was caspase-dependent as it was significantly attenuated by pre-treatment with a pan-caspase inhibitor. P21/WAF1/CIP1 was significantly up-regulated leading to cell cycle arrest. Fucoidan decreased the activation of ERK1/2 and down-regulated the activation of AKT through hypo-phosphorylation of Thr(308) residue but not Ser(473). In vivo, a xenograft model using the NB4 cells was employed. Mice were fed with fucoidan and tumor growth was measured following inoculation with NB4 cells. Subsequently, splenic natural killer (NK) cell cytotoxic activity was also examined. Oral doses of fucoidan significantly delayed tumor growth in the xenograft model and increased cytolytic activity of NK cells. Taken together, these data suggest that the selective inhibitory effect of fucoidan on APL cells and its protective effect against APL development in mice warrant further investigation of fucoidan as a useful agent in treatment of certain types of leukemia.

Gracilaria edulis exhibit antiproliferative activity against human lung adenocarcinoma cell line A549 without causing adverse toxic effect in vitro and in vivo

In the present study, the antiproliferative potential of various solvent extracts ofGracilaria edulis(GE) was tested against various cancer cell lines.

Fucoidans Disrupt Adherence of Helicobacter pylori to AGS Cells In Vitro

Fucoidans are complex sulphated polysaccharides derived from abundant and edible marine algae. Helicobacter pylori is a stomach pathogen that persists in the hostile milieu of the human stomach unless treated with antibiotics. This study aims to provide preliminary data to determine, in vitro, if fucoidans can inhibit the growth of H. pylori and its ability to adhere to gastric epithelial cells (AGS). We analysed the activity of three different fucoidan preparations (Fucus A, Fucus B, and Undaria extracts). Bacterial growth was not arrested or inhibited by the fucoidan preparations supplemented into culture media. All fucoidans, when supplemented into tissue culture media at 1000 µg mL(-1), were toxic to AGS cells and reduced the viable cell count significantly. Fucoidan preparations at 100 µg mL(-1) were shown to significantly reduce the number of adherent H. pylori. These in vitro findings provide the basis for further studies on the clinical use of sulphated polysaccharides as complementary therapeutic agents.

Fucoidan inhibition of lung cancer in vivo and in vitro : role of the Smurf2-dependent ubiquitin proteasome pathway in TGFβ receptor degradation

Fucoidan, a polysaccharide extracted from brown seaweeds, reduces tumor cell proliferation. In this study, we demonstrate that fucoidan reduces tumor size in LLC1-xenograft male C57BL/6 mice. Moreover, we found that LLC1-bearing mice continuously fed fucoidan showed greater antitumor activity than mice with discontinuous feeding. Fucoidan inhibited the in vitro growth of lung cancer cells. Transforming growth factor β (TGFβ) receptors (TGFRs) play important roles in the regulation of proliferation and progression, and high TGFRI expression in lung cancer specimens is associated with a worse prognosis. Herein, using lung cancer cells, we found that fucoidan effectively reduces TGFRI and TGFRII protein levels in vivo and in vitro. Moreover, fucoidan reduces TGFR downstream signaling events, including those in Smad2/3 and non-Smad pathways: Akt, Erk1/2, and FAK phosphorylation. Furthermore, fucoidan suppresses lung cancer cell mobility upon TGFβ stimulation. To elucidate how fucoidan decreases TGFR proteins in lung cancer cells, we found that fucoidan enhances the ubiquitination proteasome pathway (UPP)-mediated degradation of TGFRs in A549 and CL1-5 cells. Mechanistically, fucoidan promotes Smurf2 and Smad7 to conjugate TGFRs, resulting in TGF degradation; however, Smurf2-shRNA abolishes fucoidan-enhanced UPP-mediated TGFR degradation. Our study is the first to identify a novel mechanism for the antitumor activity of fucoidan, namely decreasing tumor growth by modulating the TGFR/Smad7/Smurf2-dependent axis, leading to TGFR protein degradation and inhibition of lung cancer cell progression in vitro and in vivo. Our current findings indicate that fucoidan is a potential therapeutic agent or dietary supplementation for lung cancer, acting via the Smurf2-dependent ubiquitin degradation of TGFβ receptors.

Interference with the CXCL12/CXCR4 axis as potential antitumor strategy: superiority of a sulfated galactofucan from the brown alga Saccharina latissima and fucoidan over heparins

The present study demonstrates that fucose-containing sulfated polysaccharides (FCSP) from brown algae interfere with the CXCL12/CXCR4 axis in human Burkitt's lymphoma cells by binding CXCL12 and thereby blocking both CXCL12-induced CXCR4 receptor activation and downstream effects like migration and secretion of matrix metalloproteinase-9. This mode of action is currently considered as promising strategy for tumor therapy and may contribute to the known in vivo antitumor, antimetastatic and antiangiogenic activity of FCSP. In terms of the inhibition of the CXCR4 activation, FCSP from Saccharina latissima (S.l.-FCSP) proved to be more active than a commercial "Fucoidan" from Fucus vesiculosus, and both FCSP were superior to heparins by more than one order of magnitude. Fractionation of S.l.-FCSP revealed that its main fraction is composed of a homogeneous, higher sulfated galactofucan (S.l.-SGF) which consistently exhibited stronger activities and can therefore be considered as the active ingredient of S.l.-FCSP. By subjecting Fucoidan to the same fractionation procedure, the inhibitory activity of the obtained purified Fucoidan on the CXCL12/CXCR4 axis tended to be weaker and its antioxidant and antiproliferative effects were lost. This was probably due to the separation of contaminants including phenolic compounds, whose content additionally showed marked batch-to-batch variability. Regarding the need of standardized, well-characterized FCSP preparations for any potential medical application, our results indicate that S.l.-SGF is a promising candidate for further investigations and that S. latissima may be a more appropriate source of FCSP than F. vesiculosus or other algae species with high contents of co-extractable compounds.

Antitumor Effects of Fucoidan on Human Colon Cancer Cells via Activation of Akt Signaling

We identified a novel Akt signaling mechanism that mediates fucoidan-induced suppression of human colon cancer cell (HT29) proliferation and anticancer effects. Fucoidan treatment significantly inhibited growth, induced G1-phase-associated upregulation of p21WAF1 expression, and suppressed cyclin and cyclin-dependent kinase expression in HT29 colon cancer cells. Additionally, fucoidan treatment activated the Akt signaling pathway, which was inhibited by treatment with an Akt inhibitor. The inhibition of Akt activation reversed the fucoidan-induced decrease in cell proliferation, the induction of G1-phase-associated p21WAF1 expression, and the reduction in cell cycle regulatory protein expression. Intraperitoneal injection of fucoidan reduced tumor volume; this enhanced antitumor efficacy was associated with induction of apoptosis and decreased angiogenesis. These data suggest that the activation of Akt signaling is involved in the growth inhibition of colon cancer cells treated with fucoidan. Thus, fucoidan may serve as a potential therapeutic agent for colon cancer.

Fucoidan and cancer: a multifunctional molecule with anti-tumor potential

There is a wide variety of cancer types yet, all share some common cellular and molecular behaviors. Most of the chemotherapeutic agents used in cancer treatment are designed to target common deregulated mechanisms within cancer cells. Many healthy tissues are also affected by the cytotoxic effects of these chemical agents. Fucoidan, a natural component of brown seaweed, has anti-cancer activity against various cancer types by targeting key apoptotic molecules. It also has beneficial effects as it can protect against toxicity associated with chemotherapeutic agents and radiation. Thus the synergistic effect of fucoidan with current anti-cancer agents is of considerable interest. This review discusses the mechanisms by which fucoidan retards tumor development, eradicates tumor cells and synergizes with anti-cancer chemotherapeutic agents. Challenges to the development of fucoidan as an anti-cancer agent will also be discussed.

Fucoidan promotes osteoblast differentiation via JNK- and ERK-dependent BMP2-Smad 1/5/8 signaling in human mesenchymal stem cells

Fucoidan has attracted attention as a potential drug because of its biological activities, which include osteogenesis. However, the molecular mechanisms involved in the osteogenic activity of fucoidan in human alveolar bone marrow-derived mesenchymal stem cells (hABM-MSCs) remain largely unknown. We investigated the action of fucoidan on osteoblast differentiation in hABM-MSCs and its impact on signaling pathways. Its effect on proliferation was determined using the crystal violet staining assay. Osteoblast differentiation was evaluated based on alkaline phosphatase (ALP) activity and the mRNA expression of multiple osteoblast markers. Calcium accumulation was determined by Alizarin red S staining. We found that fucoidan induced hABM-MSC proliferation. It also significantly increased ALP activity, calcium accumulation and the expression of osteoblast-specific genes, such as ALP, runt-related transcription factor 2, type I collagen-α 1 and osteocalcin. Moreover, fucoidan induced the expression of bone morphogenetic protein 2 (BMP2) and stimulated the activation of extracellular signal-related kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase by increasing phosphorylation. However, the effect of fucoidan on osteogenic differentiation was inhibited by specific inhibitors of ERK (PD98059) and JNK (SP600125) but not p38 (SB203580). Fucoidan enhanced BMP2 expression and Smad 1/5/8, ERK and JNK phosphorylation. Moreover, the effect of fucoidan on osteoblast differentiation was diminished by BMP2 knockdown. These results indicate that fucoidan induces osteoblast differentiation through BMP2-Smad 1/5/8 signaling by activating ERK and JNK, elucidating the molecular basis of the osteogenic effects of fucoidan in hABM-MSCs.