Effects of exposure to alternating low-intensity, intermediate-frequency electric fields on the differentiation of human leukemic cell line U937

Studying the bioeffects of electric fields have been the subject of ongoing research which led to promising therapeutic effect, particularly in cancer treatment. Here, we investigated the impact of low-intensity, intermediate-frequency alternating electric fields on the differentiation of human myeloid leukemia cell line U937. The results showed a near twofold increase in differentiation of U937 cells treated for 24 h by alternating 600 kHz, 150 V/m electric fields, in comparison to their control groups. This measure was evaluated by latex bead phagocytosis assay, nitro blue tetrazolium test, and cell cycle analysis which revealed a significant shift in the number of cells from G2 +M to G0 +G1 phases. The simulation result for the intracellular field intensity showed around 50% attenuation with respect to the applied external field for our setup which ruled out masking of the applied field by the internal electric noise of the cell. Based on previous studies we postulate a possible calcium-related effect for the observed differentiation, yet the exact underlying mechanism requires further investigation. Finally, our results may offer a potential therapeutic method for leukemia in the future.

Immune-Enhancing Effect of Sargassum horneri on Cyclophosphamide-Induced Immunosuppression in BALB/c Mice and Primary Cultured Splenocytes

Sargassum horneri (SH) is a seaweed that has several features that benefit health. In this study, we investigated the immune-enhancing effect of SH, focusing on the role of spleen-mediated immune functions. Chromatographic analysis of SH identified six types of monosaccharide contents, including mannose, rhamnose glucose, galactose xylose and fucose. SH increased cell proliferation of primary cultured naïve splenocytes treated with or without cyclophosphamide (CPA), an immunosuppression agent. SH also reversed the CPA-induced decrease in Th1 cytokines. In vivo investigation revealed that SH administration can increase the tissue weight of major immune organs, such as the spleen and thymus. A similar effect was observed in CPA-injected immunosuppressed BALB/c mice. SH treatment increased the weight of the spleen and thymus, blood immune cell count and Th1 cytokine expression. Additionally, the YAC-1-targeting activities of natural killer cells, which are important in innate immunity, were upregulated upon SH treatment. Overall, our study demonstrates the immune-enhancing effect of SH, suggesting its potential as a medicinal or therapeutic agent for pathologic conditions involving immunosuppression.

Prospects for the Use of Marine Sulfated Fucose-Rich Polysaccharides in Treatment and Prevention of COVID-19 and Post-COVID-19 Syndrome

Symptoms of the new coronavirus infection that appeared in 2019 (COVID-19) range from low fever and fatigue to acute pneumonia and multiple organ failure. The clinical picture of COVID-19 is heterogeneous and involves most physiological systems; therefore, drugs with a wide spectrum of mechanism of action are required. The choice of the treatment strategy for post-COVID-19 syndrome is still a challenge to be resolved. Polysaccharides with a high fucose content derived from seaweed and marine animals can form the basis for the subsequent development of promising agents for the treatment of COVID-19 and post-COVID-19 syndrome. This class of biopolymers is characterized by a variety of biological activities, including antiviral, antithrombotic, anticoagulant, hemo-stimulating, anti-inflammatory and immune-regulatory. Low molecular weight derivatives of these polysaccharides, as well as synthetic oligosaccharides with a sufficient amount and sulfation type may be considered as the most promising compounds due to their better bioavailability, which undoubtedly increases their therapeutic potential.

Marine Compounds for Melanoma Treatment and Prevention

Melanoma is considered a multifactorial disease etiologically divided into melanomas related to sun exposure and those that are not, but also based on their mutational signatures, anatomic site, and epidemiology. The incidence of melanoma skin cancer has been increasing over the past decades with 132,000 cases occurring globally each year. Marine organisms have been shown to be an excellent source of natural compounds with possible bioactivities for human health applications. In this review, we report marine compounds from micro- and macro-organisms with activities in vitro and in vivo against melanoma, including the compound Marizomib, isolated from a marine bacterium, currently in phase III clinical trials for melanoma. When available, we also report active concentrations, cellular targets and mechanisms of action of the mentioned molecules. In addition, compounds used for UV protection and melanoma prevention from marine sources are discussed. This paper gives an overview of promising marine molecules which can be studied more deeply before clinical trials in the near future.

Comparison of human peripheral blood dendritic cell activation by four fucoidans

Brown seaweed is an important source of fucoidan, which displays immunomodulatory effects by activating various immune cells. However, these effects of fucoidans from various sources of brown seaweed have not yet been explored in human blood dendritic cells. We studied fucoidans extracted from Ecklonia cava, Macrocystis pyrifera, Undaria pinnatifida, and Fucus vesiculosus for their effects on human monocyte-derived dendritic cells (MODC) and human peripheral blood DC (PBDC) activation. Ecklonia cava fucoidan (ECF) strongly upregulated co-stimulatory molecules, major histocompatibility complex class I and II, and the production of proinflammatory cytokines in MODCs and PBDCs compared to those by the other three fucoidans. Moreover, ECF elicited the strongest effect in the induction of syngeneic T cell proliferation and IFN-γ production compared to those of other fucoidans. These results suggest that ECF could be a suitable candidate molecule for enhancing immune activation in humans compared to that with the other three fucoidans.

Molecular Mechanisms Underlying Cancer Preventive and Therapeutic Potential of Algal Polysaccharides

Background:

Algal polysaccharide and oligosaccharide derivatives have been shown to possess a variety of therapeutic potentials and drug delivery applications. Algal polysaccharides contain sulfated sugar monomers derived from seaweed including brown, red, and green microalgae. Here, in this review, the recent progress of algal polysaccharides’ therapeutic applications as anticancer agents, as well as underlying cellular and molecular mechanisms was investigated. Moreover, recent progress in the structural chemistry of important polysaccharides with anticancer activities were illustrated.

Methods:

Electronic databases including “Scopus”, “PubMed”, and “Cochrane library” were searched using the keywords “cancer”, or “tumor”, or “malignancy” in title/abstract, along with “algae”, or “algal” in the whole text until July 2018. Only English language papers were included.

Results:

The most common polysaccharides involved in cancer management were sulfated polysaccharides, Fucoidans, Carageenans, and Ulvan from different species of algae that have been recognized in vitro and in vivo. The underlying anticancer mechanisms of algal polysaccharides included induction of apoptosis, cell cycle arrest, modulation of transduction signaling pathways, suppression of migration and angiogenesis, as well as activation of immune responses and antioxidant system. VEGF/VEGFR2, TGFR/Smad/Snail, TLR4/ROS/ER, CXCL12/ CXCR4, TGFR/Smad7/Smurf2, PI3K/AKT/mTOR, PBK/TOPK, and β-catenin/Wnt are among the main cellular signaling pathways which have a key role in the preventive and therapeutic effects of algal polysaccharides against oncogenesis.

Conclusion:

Algal polysaccharides play a crucial role in the management of cancer and may be considered the next frontier in pharmaceutical research. Further well-designed clinical trials are mandatory to evaluate the efficacy and safety of algal polysaccharides in patients with cancer.

Dietary Supplementation with Low-Molecular-Weight Fucoidan Enhances Innate and Adaptive Immune Responses and Protects against Mycoplasma pneumoniae Antigen Stimulation

In this study, the low-molecular-weight (LMW) fucoidan, rich in fucose and sulfate, was extracted and purified from the edible brown seaweed, Laminaria japonica. In this study, we orally administered LMW fucoidan to mice for 6 weeks. We then examined fucoidan's effects on innate immunity, adaptive immunity, and Mycoplasma pneumoniae (MP)-antigen-stimulated immune responses. Our data showed that LMW fucoidan stimulated the innate immune system by increasing splenocyte proliferation, natural killer (NK) cell activity, and phagocytic activity. LMW fucoidan also increased interleukin (IL)-2, IL-4, and interferon (IFN)-γ secretion by splenocytes and immunoglobulin (Ig)-G and IgA content in serum, which help regulate adaptive immune cell functions, and decreased allergen-specific IgE. In MP-antigen-stimulated immune responses, the IgM and IgG content in the serum were significantly higher in the LMW fucoidan group after MP-antigen stimulation. Our study provides further information about the immunomodulatory effects of LMW fucoidan and highlights a potential role in preventing M. pneumoniae infection.

Influence of Modified Fucoidan and Related Sulfated Oligosaccharides on Hematopoiesis in Cyclophosphamide-Induced Mice

Immunosuppression derived after cytostatics application in cancer chemotherapy is considered as an adverse side effect that leads to deterioration of quality of life and risk of infectious diseases. A linear sulfated (1→3)-α-l-fucan M-Fuc prepared by chemical modification of a fucoidan isolated from the brown seaweed Chordaria flagelliformis, along with two structurally related synthetic sulfated oligosaccharides, were studied as stimulators of hematopoiesis on a model of cyclophosphamide immunosuppression in mice. Recombinant granulocyte colony-stimulating factor (r G-CSF), which is currently applied in medicine to treat low blood neutrophils, was used as a reference. Polysaccharide M-Fuc and sulfated difucoside DS did not demonstrate significant effect, while sulfated octasaccharide OS showed higher activity than r G-CSF, causing pronounced neutropoiesis stimulation. In addition, production of erythrocytes and platelets was enhanced after the octasaccharide administration. The assessment of populations of cells in blood and bone marrow of mice revealed the difference in mechanisms of action of OS and r G-CSF.

The Sulfated Polysaccharides of Brown Algae and Products of Their Enzymatic Transformation as Potential Vaccine Adjuvants

The review is devoted to critical analysis of literature data, deal with effects and mechanisms of action of sulfated polysaccharides (PSs) – fucoidans from brown algae and products of their enzymatic transformation as potential adjuvants for enhancement of anti-infective and antitumor immune response. Numerous experimental data indicate that sulfated PSs demonstrate properties of vaccine adjuvants. Application perspectiveness of fucoidans as vaccine adjuvants is defined by their high biocompatibility, low-toxicity, safety and good tolerance by macroorganism, and also mechanisms of their immunomodulatory action. In particular, fucoidans are agonists of receptors of innate immunity and strong inducers of cellular and humoral immune response. At presenting the data of structural - functional interrelations, attention focused to the defining role of degree of sulfation, uronic acids and polyphenols contents, and also molecular mass in actions of fucoidans to innate and adaptive immunity cells. Insufficiency of literary data on studying of correlation of structure – physicochemical characteristics with adjuvanticities of the sulfated PSs, and also the problem of standardization of their active fractions are noted. Special attention is paid to the analysis of immunomodulatory and adjuvant activity of fucoidan oligosaccharides. Presented here results of experimental trial indicate that, despite the difficulties due to preparation of highly purified structurally characterized fractions and complex structure of fucoidans, these substances can be used as safe and effective adjuvants in vaccines against various pathogens including viruses, and also in antitumor vaccines.

Enzymatic Synthesis of GDP-α-l-fucofuranose by MtdL and Hyg20

Two mutases, MtdL and Hyg20, are reported. Both are able to functionally drive the biosynthesis of GDP-α-l-fucofuranose. Both enzymes catalyze similar functions, catalytically enabling the bidirectional reaction between GDP-β-l-fucopyranose and GDP-α-l-fucofuranose using only divalent cations as cofactors. This realization is but one of a number of important insights into fucofuranose biosynthesis presented herein.

Fucoidan and Fucosylated Chondroitin Sulfate Stimulate Hematopoiesis in Cyclophosphamide-Induced Mice

Application of cytostatics in cancer patients’ chemotherapy results in a number of side effects, including the inhibition of various parts of hematopoiesis. Two sulfated polysaccharides, fucoidan from the seaweed Chordaria flagelliformis (PS-Fuc) and fucosylated chondroitin sulfate from the sea cucumber Massinium magnum (PS-FCS), were studied as stimulators of hematopoiesis after cyclophosphamide immunosuppression in mice. Recombinant granulocyte colony-stimulating factor (r G-CSF) was applied as a reference. Both tested polysaccharides PS-Fuc and PS-FCS have a similar activity to r G-CSF, causing pronounced neutropoiesis stimulation in animals with myelosuppression induced by cyclophosphamide (CPh). Moreover, these compounds are also capable to enhance thrombopoiesis and erythropoiesis. It should be noted that PS-FCS demonstrated a greater activity than r G-CSF. The results indicate the perspective of further studies of PS-Fuc and PS-FCS, since these compounds can be considered as potentially promising stimulators of hematopoiesis. Such drugs are in demand for the accompanying treatment of cancer patients who suffer from hematological toxicity during chemo and/or radiation therapy.

Melanoma and brown seaweed: an integrative hypothesis

Although relatively rare, melanoma accounts for 2 % of cancer diagnoses globally and accounts for about 1 % of all cancer deaths. Worldwide, the annual incidence of melanoma is 272,000 cases which vary hugely, ranging from Japan where it is incredibly infrequent, to Queensland, Australia, where it is nearly 100 times higher. Based on epidemiology and laboratory studies, there is compelling evidence suggesting that seaweed might be protective against different types of cancers such as breast cancer in seaweed consuming populations. By comparing countries where melanoma is more common with countries where it is infrequent, it is possible to construct a hypothesis for how consuming brown seaweeds which may hold clues to the differences in melanoma susceptibility between Japanese and Western nations. Unlike in these other countries, where melanoma incidence has increased dramatically over the last two decades, in Japan, rates have remained remarkably low and stable. There is limited evidence from clinical studies and animal models that have used whole seaweed or isolated fractions from seaweed and measured changes in biomarkers. They have demonstrated the effectiveness of seaweed at inhibiting melanoma development and progression. In this review, the various results will be described. Although there are several effective fractions, it is proposed that consuming whole seaweeds may hold additional benefits that could be lost by consuming only a single extract.