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

Mekabu fucoidan: structural complexity and defensive effects against avian influenza A viruses

Fucoidan from the sporophyll (Mekabu) of brown seaweed Undaria pinnatifida (wakame) is interesting due to its various biological activities. Mekabu fucoidan (Mw ∼ 9 kDa) of this study (MF) was previously isolated and characterized by chemical and separation methods including GPC and methylation analysis (Lee, Hayashi, Hashimoto, Nakano, & Hayashi, 2004). It was found that this fucoidan composed of partially sulphated (DS ∼ 0.72) fucose and galactose at approximately equal amounts. Methylation analyses revealed complex structure of MF. However, it has been still unclear about the linkages between units and substitution patterns. To solve these structural tasks, spectroscopic methods (FTIR, FT Raman and NMR) were used in the analysis of native MF and its deesterified derivatives. According to obtained results, this polysaccharide was defined as O-acetylated sulphated fucogalactan. The defensive effects of MF were evaluated on mice infected with avian influenza A viruses (H5N3 and H7N2 subtypes); its efficacy was determined in reducing viral replication and increasing antibody production. Oral administration of MF resulted in suppressing virus yields. In addition, the production of neutralizing antibodies and mucosal IgA in the animals inoculated with the avian influenza A viruses was significantly increased. These results suggested that MF could be used for the prevention of viral infection.

Anticancer effects of different seaweeds on human colon and breast cancers

Seafoods and seaweeds represent some of the most important reservoirs of new therapeutic compounds for humans. Seaweed has been shown to have several biological activities, including anticancer activity. This review focuses on colorectal and breast cancers, which are major causes of cancer-related mortality in men and women. It also describes various compounds extracted from a range of seaweeds that have been shown to eradicate or slow the progression of cancer. Fucoidan extracted from the brown algae Fucus spp. has shown activity against both colorectal and breast cancers. Furthermore, we review the mechanisms through which these compounds can induce apoptosis in vitro and in vivo. By considering the ability of compounds present in seaweeds to act against colorectal and breast cancers, this review highlights the potential use of seaweeds as anticancer agents.

Fucoidan induces apoptosis of HepG2 cells by down-regulating p-Stat3

Fucoidan is one of the main bioactive components of polysaccharides. The current study was focused on the anti-tumor effects of fucoidan on human heptoma cell line HepG2 and the possible mechanisms. Fucoidan treatment resulted in cell cycle arrest and apoptosis of HepG2 cells in a dose-dependent manner detected by MTT assay, flow cytometry and fluorescent microscopy. The results of flow cytometric analysis revealed that fucoidan induced G2/M arrest in the cell cycle progression. Hoechst 33258 and Annexin V/PI staining results showed that the apoptotic cell number was increased, which was associated with a dose-dependent up-regulation of Bax and down-regulation of Bcl-2 and p-Stat3. In parallel, the up-regulation of p53 and the increase in reactive oxygen species were also observed, which may play important roles in the inhibition of HepG2 growth by fucoidan. In the meantime, Cyclin B1 and CDK1 were down-regulated by fucoidan treatment. Down-regulation of p-Stat3 by fucoidan resulted in apoptosis and an increase in ROS in response to fucoidan exposure. We therefore concluded that fucoidan induces apoptosis through the down-regulation of p-Stat3. These results suggest that fucoidan may be used as a novel anti-cancer agent for hepatocarcinoma.

Fucoidan as a marine anticancer agent in preclinical development

Fucoidan is a fucose-containing sulfated polysaccharide derived from brown seaweeds, crude extracts of which are commercially available as nutritional supplements. Recent studies have demonstrated antiproliferative, antiangiogenic, and anticancer properties of fucoidan in vitro. Accordingly, the anticancer effects of fucoidan have been shown to vary depending on its structure, while it can target multiple receptors or signaling molecules in various cell types, including tumor cells and immune cells. Low toxicity and the in vitro effects of fucoidan mentioned above make it a suitable agent for cancer prevention or treatment. However, preclinical development of natural marine products requires in vivo examination of purified compounds in animal tumor models. This review discusses the effects of systemic and local administration of fucoidan on tumor growth, angiogenesis, and immune reaction and whether in vivo and in vitro results are likely applicable to the development of fucoidan as a marine anticancer drug.

AKT signaling is involved in fucoidan-induced inhibition of growth and migration of human bladder cancer cells

We identified a novel mechanism of AKT signaling in the fucoidan-induced proliferation and migration of human urinary 5637 cancer cells. Fucoidan treatment showed a significant growth inhibition followed by G1-phase-associated up-regulation of p21WAF1 expression and suppression of cyclins and CDK expression in 5637 cells. Also, fucoidan treatment induced the activation of AKT signaling, which was inhibited by treatment with wortmannin, a PI3K-specific inhibitor. Blockade of the AKT function reversed the fucoidan-mediated inhibition of cell proliferation, the increased G1-phase-associated p21WAF1 expression, and the reduction of cell-cycle proteins. Moreover, treatment with fucoidan blocked migration and invasion of 5637 cells. This inhibition was attributed to decreased expression of MMP-9, which was mediated by down-regulation of AP-1 and NF-κB binding activity. Furthermore, wortmannin treatment abolished the decreased cell migration and invasion and the inhibition of MMP-9 expression via the suppression of NF-κB and AP-1 in fucoidan-treated cells. Similar results were observed in another bladder cancer T-24 cells treated with fucoidan. Finally, overexpression of the AKT gene inhibited the proliferation, migration and invasion of bladder cancer cells. These data suggest that the activation of AKT signaling is involved in growth inhibition and suppression of the migration and invasion of bladder cancer cells treated with fucoidan.

Undaria pinnatifida soluble fiber regulates Angptl3-LPL pathway to lessen hyperlipidemia in mice

Angiopoietin-like protein 3 (Angptl3)-lipoprotein lipase (LPL) pathway may be a useful pharmacologic target for hyperlipidemia. The present study was conducted to test the effect of soluble fiber extracted from Undaria pinnatifida (UP), on hyperlipidemia in apolipoprotein E-deficient (ApoE(-/-)) mice. Forty mice were divided into four groups (n = 10): control group (C57BL/6J mice), ApoE(-/-) mice group, and two groups of ApoE(-/-) mice treated with UP fiber (5 or 10 % per day). UP soluble fiber treatment significantly decreased plasma and hepatic total cholesterol, triglycerides levels, plasma low-density lipoprotein cholesterol, and malondialdehyde concentrations and increased plasma high-density lipoprotein cholesterol level and downregulated protein expression of Angptl3 concomitantly with upregulated protein expression of LPL. In addition, T0901317 caused elevated expression of hepatic Angptl3 protein, and the effect of T0901317 was also abrogated by UP soluble fiber in C57BL/6J mice. The present results suggest that the UP soluble fiber regulates Angptl3-LPL pathway to lessen hyperlipidemia in mice.

Fucoidan induces caspase-dependent apoptosis in MC3 human mucoepidermoid carcinoma cells

Fucoidan is a sulfated polysaccharide present in brown algae that has been identified to exhibit multiple biological effects. In this study, the apoptotic effects of fucoidan in MC3 human mucoepidermoid carcinoma (MEC) cells were investigated. The apoptotic effects of fucoidan on MC3 MEC cells were evaluated by cell proliferation assay, 4′,6-diamidino-2-phenylindole staining and western blot analysis. The results showed that fucoidan decreased cell proliferation and induced caspase-dependent apoptosis in MC3 MEC cells. Fucoidan downregulated the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, whereas phospho-p38 mitogen-activated protein kinase or phospho-c-Jun NH₂-terminal kinase (JNK) levels were not altered. In addition, fucoidan significantly decreased the expression levels of myeloid cell leukemia-1 (Mcl-1). These results suggest that fucoidan is able to modulate the ERK1/2 pathway and thereby regulate Mcl-1 protein expression and induce apoptosis in MC3 MEC cells. Therefore, fucoidan may be a promising agent for the treatment of human MEC.

A noncanonical NF-κB pathway through the p50 subunit regulates Bcl-2 overexpression during an oxidative-conditioning hormesis response

Cells can respond to damage and stress by activating various repair and survival pathways. One of these responses can be induced by preconditioning the cells with sublethal stress to provoke a prosurvival response that will prevent damage and death, and which is known as hormesis. Bcl-2, an antiapoptotic protein recognized by its antioxidant and prosurvival functions, has been documented to play an important role during oxidative-conditioning hormesis. Using an oxidative-hormetic model, which was previously established in the L929 cell line by subjecting the cells to a mild oxidative stress of 50 μM H₂O₂ for 9 h, we identified two different transductional mechanisms that participate in the regulation of Bcl-2 expression during the hormetic response. These mechanisms converge in activating the nuclear transcription factor NF-κB. Interestingly, the noncanonical p50 subunit of the NF-κB family is apparently the subunit that participates during the oxidative-hormetic response.

Fucoidan inhibited 4T1 mouse breast cancer cell growth in vivo and in vitro via downregulation of Wnt/β-catenin signaling

Fucoidan is a sulfated polysaccharide derived from brown algae and is known to possess anticancer properties. However, the relationship between fucoidan and β-catenin, one of the key components of the Wnt signaling pathway, in mouse breast cancer remains poorly characterized. In this study, mouse breast cancer cells (4T1) were exposed to fucoidan to investigate the relationship between fucoidan and the Wnt/β-catenin signaling pathway in vivo and in vitro. We found that fucoidan significantly inhibited cell growth, increased cell death, and induced G1 cell cycle arrest in 4T1 cells. Fucoidan also reduced β-catenin expression and T cell factor/lymphoid-enhancing factor reporter activity. Furthermore, fucoidan downregulated the expression of downstream target genes such as c-myc, cyclin D1, and survivin. Intraperitoneal injection of fucoidan in tumor-bearing mice reduced the tumor volume and weight. Fucoidan induced aberrant downregulation of β-catenin in tumor tissues with a significant increase in apoptosis. Thus, our data suggested that fucoidan exerts its anticancer activity through downregulation of Wnt/β-catenin signaling. Fucoidan may be an effective therapy for the chemoprevention and treatment of mouse breast cancer.

The anticancer effect of fucoidan in PC-3 prostate cancer cells

Fucoidan, a sulfated polysaccharide, has a variety of biological activities, such as anti-cancer, anti-angiogenic and anti-inflammatory. However, the mechanisms of action of fucoidan as an anti-cancer agent have not been fully elucidated. The present study examined the anti-cancer effect of fucoidan obtained from Undaria pinnatifida in PC-3 cells, human prostate cancer cells. Fucoidan induced the apoptosis of PC-3 cells by activating both intrinsic and extrinsic pathways. The induction of apoptosis was accompanied by the activation of extracellular signal-regulated kinase mitogen-activated protein kinase (ERK1/2 MAPK) and the inactivation of p38 MAPK and phosphatidylinositol 3-kinase (PI3K)/Akt. In addition, fucoidan also induced the up-regulation of p21Cip1/Waf and down-regulation of E2F-1 cell-cycle-related proteins. Furthermore, in the Wnt/β-catenin pathway, fucoidan activated GSK-3β that resulted in the decrease of β-catenin level, followed by the decrease of c-myc and cyclin D1 expressions, target genes of β-catenin in PC-3 cells. These results suggested that fucoidan treatment could induce intrinsic and extrinsic apoptosis pathways via the activation of ERK1/2 MAPK, the inactivation of p38 MAPK and PI3K/Akt signaling pathway, and the down-regulation of Wnt/β-catenin signaling pathway in PC-3 prostate cancer cells. These data support that fucoidan might have potential for the treatment of prostate cancer.

Photoprotective effect of Undaria crenata against ultraviolet B-induced damage to keratinocytes

Chronic exposure of the skin to ultraviolet B (UVB) radiation induces oxidative stress, which plays a crucial role in the induction of skin cancer. The brown alga Undaria crenata is a potential source of antioxidant and anti-apoptotic compounds due to its capacity to produce protective compounds against environmental factors, including UV radiation. The aim of this study was to investigate the photoprotective properties of an U. crenata ethanol extract (UCE) against UVB-induced cell damage in human HaCaT keratinocytes. UCE exhibited absorbing effect of UVB (280-320 nm) and scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl radical and intracellular reactive oxygen species induced by hydrogen peroxide and UVB rays. Furthermore, electron spin resonance spectrometry revealed the significant scavenging effect of UCE against superoxide anion and hydroxyl radical. UCE reduced UVB-induced apoptosis, as shown by a decrease in apoptotic bodies and nuclear and DNA fragmentation, resulting in the recovery of cell viability. UCE also decreased the degree of UVB-induced oxidative stress to lipids, proteins, and DNA as shown by a decrease in 8-isoprostane level, protein carbonylation and DNA tails. These results suggest that UCE protects human keratinocytes against UVB-induced oxidative stress.

The effect of sulfated (1→3)-α-l-fucan from the brown alga Saccharina cichorioides Miyabe on resveratrol-induced apoptosis in colon carcinoma Cells

Accumulating data clearly indicate that the induction of apoptosis by nontoxic natural compounds is a potent defense against the development and progression of many malignancies, including colon cancer. Resveratrol and the fucoidans have been shown to possess potent anti-tumor activity in vitro and in vivo. The aim of the present study was to examine whether the combination of a fucoidan from the brown alga Saccharina cichorioides Miyabe and resveratrol would be an effective preventive and/or therapeutic strategy against colon cancer. Based on NMR spectroscopy and MALDI-TOF analysis, the fucoidan isolated and purified from Saccharina cichorioides Miyabe was (1→3)-α-l-fucan with sulfate groups at C2 and C4 of the α-l-fucopyranose residues. The fucoidan enhanced the antiproliferative activity of resveratrol at nontoxic doses and facilitated resveratrol-induced apoptosis in the HCT 116 human colon cancer cell line. Apoptosis was realized by the activation of initiator caspase-9 and effector caspase-7 and -3, followed by the cleavage of PARP. Furthermore, significant inhibition of HCT 116 colony formation was associated with the sensitization of cells to resveratrol by the fucoidan. Taken together, these results demonstrate that the combination of the algal fucoidan with resveratrol may provide a potential therapy against human colon cancer.

Antiproliferative activity of fucan nanogel

Sulfated fucans comprise families of polydisperse natural polysaccharides based on sulfated L-fucose. Our aim was to investigate whether fucan nanogel induces cell-specific responses. To that end, a non toxic fucan extracted from Spatoglossum schröederi was chemically modified by grafting hexadecylamine to the polymer hydrophilic backbone. The resulting modified material (SNFuc) formed nanosized particles. The degree of substitution with hydrophobic chains was close to 100%, as estimated by elemental analysis. SNFfuc in aqueous media had a mean diameter of 123 nm and zeta potential of -38.3 ± 0.74 mV, as measured by dynamic light scattering. Nanoparticles conserved their size for up to 70 days. SNFuc cytotoxicity was determined using the MTT assay after culturing different cell lines for 24 h. Tumor-cell (HepG2, 786, H-S5) proliferation was inhibited by 2.0%-43.7% at nanogel concentrations of 0.05-0.5 mg/mL and rabbit aorta endothelial cells (RAEC) non-tumor cell line proliferation displayed inhibition of 8.0%-22.0%. On the other hand, nanogel improved Chinese hamster ovary (CHO) and monocyte macrophage cell (RAW) non-tumor cell line proliferation in the same concentration range. The antiproliferative effect against tumor cells was also confirmed using the BrdU test. Flow cytometric analysis revealed that the fucan nanogel inhibited 786 cell proliferation through caspase and caspase-independent mechanisms. In addition, SNFuc blocks 786 cell passages in the S and G2-M phases of the cell cycle.

Anticancer properties and mechanisms of fucoidan on mouse breast cancer in vitro and in vivo

BACKGROUND

Fucoidan is a sulfated polysaccharide derived from brown algae that has been reported to perform multiple biological activities, including antitumor activity. In this study, we examined the influence of crude fucoidan on mouse breast cancer in vitro and in vivo.

MATERIALS AND METHODS

In vitro, fluorescent staining, flow cytometry and Western blot were performed to analyze apoptosis and vascular endothelial growth factor (VEGF) expression of mouse breast cancer 4T1 cells. In vivo, therapy experiments were conducted on Babl/c mice bearing breast cancer. The tumor volume and weight were measured. The number of apoptotic cells and microvascular density (MVD) in tumor tissues were assessed by TUNEL and CD34 immunostaining. Immunohistochemical assays and ELISA assay were used to detect the expression of VEGF in tissues.

RESULTS

In vitro studies showed that crude fucoidan significantly decreased the viable number of 4T1 cells, induced apoptosis and down-regulated the expression of VEGF. The expression of Bcl-2 was decreased, and the ratio of Bcl-2 to Bax was significantly decreased. The expression of Survivin and phosphorylated extracellular signal regulated protein kinases (ERKs) was decreased. Cytochrome C was released from mitochondria into cytosol, and the cleaved Caspase-3 protein rose after fucoidan treatment. Intraperitoneal injection of fucoidan in breast cancer models reduced the tumor volume and weight. The enhanced antitumor efficacy was associated with decreased angiogenesis and increased induction of apoptosis.

CONCLUSION

These findings indicated that crude fucoidan inhibited mouse breast cancer growth in vitro and in vivo. These data suggest that fucoidan may serve as a potential therapeutic agent for breast cancer.

Anticancer polysaccharides from natural resources: a review of recent research

Taking into account the rising trend of the incidence of cancers of various organs, effective therapies are urgently needed to control human malignancies. However, almost all of the chemotherapy drugs currently on the market cause serious side effects. Fortunately, several previous studies have shown that some non-toxic biological macromolecules, including polysaccharides and polysaccharide-protein complexes, possess anti-cancer activities or can increase the efficacy of conventional chemotherapy drugs. Based on these encouraging observations, a great deal of effort has been focused on discovering anti-cancer polysaccharides and complexes for the development of effective therapeutics for various human cancers. This review focuses on the advancements in the anti-cancer efficacy of various natural polysaccharides and polysaccharide complexes in the past 5 years. Most polysaccharides were tested using model systems, while several involved clinical trials.

[Breath test using C-13-trioleate in the evaluation of the rate of fatty acid metabolism after parenteral feeding of premature and newborn infants]

Malignant glioma (MG) is a poor prognostic brain tumor with inevitable recurrence after multimodality treatment. Searching for more effective treatment is urgently needed. Differentiation induction via epigenetic modification has been proposed as a potential anticancer strategy. Natural products are known as fruitful sources of epigenetic modifiers with wide safety margins. We thus explored the effects of oligo-fucoidan (OF) from brown seaweed on this notion in MG cells including Grade III U87MG cells and Grade IV glioblastoma multiforme (GBM)8401 cells and compared to the immortalized astrocyte SVGp12 cells. The results showed that OF markedly suppress the proliferation of MG cells and only slightly affected that of SVGp12 cells. OF inhibited the protein expressions of DNA methyltransferases 1, 3A and 3B (DNMT1, 3A and 3B) accompanied with obvious mRNA induction of differentiation markers (MBP, OLIG2, S100β, GFAP, NeuN and MAP2) both in U87MG and GBM8401 cells. Accordingly, the methylation of p21, a DNMT3B target gene, was decreased by OF. In combination with the clinical DNMT inhibitor decitabine, OF could synergize the growth inhibition and MBP induction in U87MG cells. Appropriated clinical trials are warranted to evaluate this potential complementary approach for MG therapy after confirmation of the effects in vivo.