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

Carbohydrate polymer-functionalized metal nanoparticles in cancer therapy: A review

Metal nanoparticles have been emerged as promising candidates in cancer therapy because of their large surface area, optical properties and ROS generation. Therefore, these nanoparticles are able to mediate cell death through hyperthermia, photothermal therapy and ROS-triggered apoptosis. The various metal nanoparticles including gold, silver and iron oxide nanostructures have been exploited for the theranostic application. Moreover, precision oncology and off-targeting features can be improved by metal nanoparticles. The modification of metal nanoparticles with carbohydrate polymers including chitosan, hyaluronic acid, cellulose, agarose, starch and pectin, among others can significantly improve their anti-cancer activities. Carbohydrate polymers have been idea for the purpose of drug delivery due to their biocompatibility, biodegradability and increasing nanoparticle stability. In addition, carbohydrate polymers are able to improve drug delivery, cellular uptake and sustained release of cargo. Such nanoparticles are capable of responding to the specific stimuli in the tumor microenvironment including pH and light. Furthermore, the carbohydrate polymer-modified metal nanoparticles can be utilized for the combination of chemotherapy, phototherapy and immunotherapy. Since the biocompatibility and long-term safety are critical factors for the clinical translation of nanoparticles, the modification of metal nanoparticles with carbohydrate polymers can improve this way to the application in clinic.

A review on structure, bioactivity, mechanism, structure-activity relationship and application of anti-breast cancer polysaccharides

Breast cancer (BC) is one of the most common female malignant tumors. BC treatment depends on the use of chemotherapeutic drugs, causing various adverse effects. Increasing evidence has shown that natural polysaccharides (NPs) are potential adjuvants or substitutes for anti-BC drugs. However, the information regarding anti-BC NPs remains scattered. Thus, the recent progress in the structure, bioactivity, mechanism and application of anti-BC NPs is comprehensively summarized in this review. Moreover, the structure-activity relationship is discussed. Additionally, the prospects for future work are proposed. Recent studies have shown that anti-BC NPs have diverse structural features, which are affected by the extraction and purification methods. NPs show anti-BC activities in cell and animal experiments as well as in clinical researches, and enhance anti-BC effects of chemotherapeutic drugs in cell and animal experiments. The anti-BC mechanisms of NPs include anti-proliferation, inducing apoptosis, anti-metastasis and anti-invasion, immunoenhancement, gut microbiota regulation and others. The anti-BC activities of NPs are influenced by molecular weight, monosaccharide composition, functional groups, glycosidic bond types, backbone and side chains. NPs-based nanoparticles, nanocarriers, drug delivery systems, nanocomposites and other materials can also be used in anti-BC. This review provides theoretical bases for future research and functional application of NPs in anti-BC.

Natural products‐based antiangiogenic agents: New frontiers in cancer therapy

Angiogenesis, vital for tumor growth and metastasis, is a promising target in cancer therapy. Natural compounds offer potential as antiangiogenic agents with reduced toxicity. This review provides a comprehensive overview of natural product‐based antiangiogenic therapies, focusing on molecular mechanisms and therapeutic potential. A systematic search identified relevant articles from 2019 to 2023. Various natural compounds, including polyphenols, terpenes, alkaloids, cannabinoids, omega‐3 fatty acids, polysaccharides, proteins, and carotenoids, were investigated for their antiangiogenic properties. Challenges such as dose standardization, routes of administration, and potential side effects remain. Further studies, including in‐depth animal models and human epidemiological studies, must elucidate clinical efficacy and safety. Synergistic effects with current antiangiogenic therapies, such as bevacizumab and tyrosine kinase inhibitors, should be explored. Additionally, the potential hormone‐dependent effects of compounds like genistein highlight the need for safety evaluation. In conclusion, natural products hold promise as adjunctive therapies to conventional antineoplastic drugs in modulating angiogenesis in cancer. However, robust clinical trials are needed to validate preclinical findings and ensure safety and efficacy.

Blocking the WNT/β-catenin pathway in cancer treatment:pharmacological targets and drug therapeutic potential

The WNT/β-catenin signaling pathway plays crucial roles in tumorigenesis and relapse, metastasis, drug resistance, and tumor stemness maintenance. In most tumors, the WNT/β-catenin signaling pathway is often aberrantly activated. The therapeutic usefulness of inhibition of WNT/β-catenin signaling has been reported to improve the efficiency of different cancer treatments and this inhibition of signaling has been carried out using different methods including pharmacological agents, short interfering RNA (siRNA), and antibodies. Here, we review the WNT-inhibitory effects of some FDA-approved drugs and natural products in cancer treatment and focus on recent progress of the WNT signaling inhibitors in improving the efficiency of chemotherapy, immunotherapy, gene therapy, and physical therapy. We also classified these FDA-approved drugs and natural products according to their structure and physicochemical properties, and introduced briefly their potential mechanisms of inhibiting the WNT signaling pathway. The review provides a comprehensive understanding of inhibitors of WNT/β-catenin pathway in various cancer therapeutics. This will benefit novel WNT inhibitor development and optimal clinical use of WNT signaling-related drugs in synergistic cancer therapy.

Biopolymeric nanocarriers in cancer therapy: unleashing the potency of bioactive anticancer compounds for enhancing drug delivery

Effective cancer treatment is becoming a global concern, and recent developments in nanomedicine are essential for its treatment. Cancer is a severe metabolic syndrome that affects the human population and is a significant contributing factor to deaths globally. In science, nanotechnology offers rapidly developing delivery methods for natural bioactive compounds that are becoming increasingly prominent and can be used to treat diseases in a site-specific way. Chemotherapy and radiotherapy are conventional approaches for preventing cancer progression and have adverse effects on the human body. Many chemically synthesized drugs are used as anticancer agents, but they have several side effects; hence, they are less preferred. Medicinal plants and marine microorganisms represent a vast, mostly untapped reservoir of bioactive compounds for cancer treatment. However, they have several limitations, including nonspecific targeting, weak water solubility and limited therapeutic potential. An alternative option is the use of biopolymeric nanocarriers, which can generate effective targeted treatment therapies when conjugated with natural anticancer compounds. The present review focuses on biopolymeric nanocarriers utilizing natural sources as anticancer drugs with improved tumor-targeting efficiency. This review also covers various natural anticancer compounds, the advantages and disadvantages of natural and synthetic anticancer compounds, the problems associated with natural anticancer drugs and the advantages of biopolymeric nanocarriers over synthetic nanocarriers as drug delivery agents. This review also discusses various biopolymeric nanocarriers for enhancing the controlled delivery of anticancer compounds and the future development of nanomedicines for treating cancer.

Opportunities and challenges of fucoidan for tumors therapy

The large-scale collections, screening and discovery of biologically active and pharmacologically significant marine-derived natural products have garnered tremendous attraction. Edible brown algae are rich in fucoidan. Importantly, fucoidan has been reported to inhibit carcinogenesis and metastasis mainly through the regulation of deregulated cell signaling pathways. This review summarizes the structural features of fucoidan, including monosaccharide type, sulfate content, and main chain structure. We have set spotlight on fucoidan-mediated tumor suppressive effects in cell cultures studies and tumor-bearing rodent models. Fucoidan exerts anti-tumor effects primarily through the inhibition of tumor cell viability, proliferation and metastatic dissemination of cancer cells from primary tumor sites to distant secondary sites. Fucoidan not only promotes immunological responses in tumor microenvironment but also induces apoptotic death in cancer cells. In addition, fucoidan can be used as a dietary supplement for preventive purposes, in combination with other drugs as complementary and alternative medicine or with nanoparticle modifications will be the future of fucoidan use. Cutting-edge research related to fucoidan has catalyzed the transition of fucoidan from preclinical studies to different phases of clinical trials. Rationally designed clinical trials for the critical evaluation of fucoidan against different cancers will be valuable to reap full benefits.

Molecular targets and therapeutic strategies for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is known for its heterogeneous complexity and is often difficult to treat. TNBC lacks the expression of major hormonal receptors like estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 and is further subdivided into androgen receptor (AR) positive and AR negative. In contrast, AR negative is also known as quadruple-negative breast cancer (QNBC). Compared to AR-positive TNBC, QNBC has a great scarcity of prognostic biomarkers and therapeutic targets. QNBC shows excessive cellular growth and proliferation of tumor cells due to increased expression of growth factors like EGF and various surface proteins. This study briefly reviews the limited data available as protein biomarkers that can be used as molecular targets in treating TNBC as well as QNBC. Targeted therapy and immune checkpoint inhibitors have recently changed cancer treatment. Many studies in medicinal chemistry continue to focus on the synthesis of novel compounds to discover new antiproliferative medicines capable of treating TNBC despite the abundance of treatments currently on the market. Drug repurposing is one of the therapeutic methods for TNBC that has been examined. Moreover, some additional micronutrients, nutraceuticals, and functional foods may be able to lower cancer risk or slow the spread of malignant diseases that have already been diagnosed with cancer. Finally, nanomedicines, or applications of nanotechnology in medicine, introduce nanoparticles with variable chemistry and architecture for the treatment of cancer. This review emphasizes the most recent research on nutraceuticals, medication repositioning, and novel therapeutic strategies for the treatment of TNBC.

In silico molecular docking, molecular dynamics, ADMET analysis of fucoidan against receptor frizzled-8 and coreceptor LRP6 in Wnt/β-Catenin pathway and in vitro analysis of fucoidan extract from Sargassum echinocarpum as β-catenin inhibitor in breast cancer cell line (MCF-7)

This study aimed to investigate the effect of fucoidan on the Wnt/β-Catenin pathway using both in-silico molecular docking, molecular dynamics, ADMET analysis (in frizzled-8 receptor and LRP6 coreceptor) and in-vitro experiments using MCF-7 breast cancer cells. Through the molecular docking analysis, the binding energies on the frizzled-8 receptor were -5.6, -5.1, -9.4, and -8.8 kcal/mol, respectively. Meanwhile, those on the LRP6 receptor, were -7.3, -6.2, -10.0, and -9.8 kcal/mol, respectively. The results showed that fucoidan had a favorable binding affinity for both receptors. Furthermore, it was discovered to reduce the interaction and binding affinity between Wnt agonists to frizzled-8 and LRP6 receptors. This reduction was reflected in the change in the binding energy of the fucoidan-Wnt agonist-frizzled 8 and fucoidan-Wnt agonist-LRP6 complexes, which exhibited decreases of -7.0 kcal/mol and -7.8 kcal/mol, respectively. Fucoidan was found stable in complexes with frizzled-8 receptor and co-receptor LRP6. ADMET study showed it's non-carcinogenic and can be distributed in the body. Fucoidan effectively inhibited β-catenin production, a critical factor in the Wnt/β-catenin pathway. The MCF-7 breast cancer cells were treated with fucoidan extract from S. echinocarpum at incubation times of 24, 48, and 72 h, resulting in a reduction of β-catenin levels by 95.19%, 83.88%, and 80.88%, respectively. Fucoidan also shows no significant difference in value compared to fucoidan standard (F. vesiculosus) and doxorubicin. Fucoidan exhibited antiproliferative effects against breast cancer cells, specifically through its modulation of the Wnt/β-Catenin pathway, and held great potential as an herbal anticancer agent.Communicated by Ramaswamy H. Sarma.

Polysaccharides from marine biological resources and their anticancer activity on breast cancer

In recent decades, natural products from marine organisms have been widely studied for the treatment of various breast cancers. Among them, polysaccharides have been favored by researchers because of their good effects and safety. In this review, polysaccharides from marine algae including macroalgae and microalgae, chitosan, microorganisms such as marine bacteria and fungi, and starfish are addressed. Their anticancer activities on different breast cancers and action mechanisms are discussed in detail. In general, polysaccharides from marine organisms are potential sources of low side-effect and high efficiency anticancer drugs for development. However, further research on animals and clinical research are needed.

Cancer-targeted fucoidan‑iron oxide nanoparticles for synergistic chemotherapy/chemodynamic theranostics through amplification of P-selectin and oxidative stress

A combination of chemotherapy and chemodynamic therapy (CDT) is being developed to improve the theranostic efficacy and biological safety of current therapies. However, most CDT agents are restricted due to complex issues such as multiple components, low colloidal stability, carrier-associated toxicity, insufficient reactive oxygen species generation, and poor targeting efficacy. To overcome these problems, a novel nanoplatform composed of fucoidan (Fu) and iron oxide (IO) nanoparticles (NPs) was developed to achieve chemotherapy combined with CDT synergistic treatment with a facile self-assembling manner, and the NPs were made up of Fu and IO, in which the Fu was not only used as a potential chemotherapeutic but was also designed to stabilize the IO and target P-selectin-overexpressing lung cancer cells, thereby producing oxidative stress and thus synergizing the CDT efficacy. The Fu-IO NPs exhibited a suitable diameter below 300 nm, which favored their cellular uptake by cancer cells. Microscopic and MRI data confirmed the lung cancer cellular uptake of the NPs due to active Fu targeting. Moreover, Fu-IO NPs induced efficient apoptosis of lung cancer cells, and thus offer significant anti-cancer functions by potential chemotherapeutic-CDT.

The effects of traditional Chinese medicine and dietary compounds on digestive cancer immunotherapy and gut microbiota modulation: A review

Digestive tract-related cancers account for four of the top ten high-risk cancers worldwide. In recent years, cancer immunotherapy, which exploits the innate immune system to attack tumors, has led to a paradigm shifts in cancer treatment. Gut microbiota modification has been widely used to regulate cancer immunotherapy. Dietary compounds and traditional Chinese medicine (TCM) can alter the gut microbiota and its influence on toxic metabolite production, such as the effect of iprindole on lipopolysaccharide (LPS), and involvement in various metabolic pathways that are closely associated with immune reactions. Therefore, it is an effective strategy to explore new immunotherapies for gastrointestinal cancer to clarify the immunoregulatory effects of different dietary compounds/TCMs on intestinal microbiota. In this review, we have summarized recent progress regarding the effects of dietary compounds/TCMs on gut microbiota and their metabolites, as well as the relationship between digestive cancer immunotherapy and gut microbiota. We hope that this review will act as reference, providing a theoretical basis for the clinical immunotherapy of digestive cancer via gut microbiota modulation.

Advances in anti-cancer effects and underlying mechanisms of marine algae polysaccharides

Cancer is a leading cause of death in both developing and developed countries. With the increase in the average global life expectancy, it has become a major health problem and burden for most public healthcare systems worldwide. Due to the fewer side effects of natural compounds than of chemotherapeutic drugs, increasing scientific attention is being focused on the development of anti-cancer drugs derived from natural sources. Marine algae are an interesting source of functional compounds with diverse health-promoting activities. Among these compounds, polysaccharides have attracted considerable interest for many years because of their excellent anti-cancer abilities. They improve the efficacy of conventional chemotherapeutic drugs with relatively low toxicity to normal human cells. However, there are few reviews summarising the unique anti-cancer effects and underlying mechanisms of marine algae polysaccharides (MAPs). Thus, the current review focuses on updating the advances in the discovery and evaluation of MAPs with anti-cancer properties and the elucidation of their mechanisms of action, including the signalling pathways involved. This review aims to provide a deeper understanding of the anti-cancer functions of the natural compounds derived from medicinal marine algae and thereby offer a new perspective on cancer prevention and therapy with high effectiveness and safety.

Countering Triple Negative Breast Cancer via Impeding Wnt/β-Catenin Signaling, a Phytotherapeutic Approach

Triple negative breast cancer (TNBC) is characterized as a heterogeneous disease with severe malignancy and high mortality. Aberrant Wnt/β-catenin signaling is responsible for self-renewal and mammosphere generation, metastasis and resistance to apoptosis and chemotherapy in TNBC. Nonetheless, in the absence of a targeted therapy, chemotherapy is regarded as the exclusive treatment strategy for the treatment of TNBC. This review aims to provide an unprecedented overview of the plants and herbal derivatives which repress the progression of TNBC through prohibiting the Wnt/β-catenin pathway. Herbal medicine extracts and bioactive compounds (alkaloids, retinoids. flavonoids, terpenes, carotenoids and lignans) alone, in combination with each other and/or with chemotherapy agents could interrupt the various steps of Wnt/β-catenin signaling, i.e., WNT, FZD, LRP, GSK3β, Dsh, APC, β-catenin and TCF/LEF. These phytotherapy agents diminish proliferation, metastasis, breast cancer stem cell self-renewal and induce apoptosis in cell and animal models of TNBC through the down-expression of the downstream target genes of Wnt signaling. Some of the herbal derivatives simultaneously impede Wnt/β-catenin signaling and other overactive pathways in triple negative breast cancer, including: mTORC1; ER stress and SATB1 signaling. The herbal remedies and their bioactive ingredients perform essential roles in the treatment of the very fatal TNBC via repression of Wnt/β-catenin signaling.

Brown Algae-Derived Fucoidan Exerts Oxidative Stress-Dependent Antiproliferation on Oral Cancer Cells

Fucoidan is a dietary brown algae-derived fucose-rich polysaccharide. However, the anticancer effects of fucoidan for oral cancer treatment remain unclear, particularly in terms of its preferential antiproliferation ability and oxidative-stress-associated responses. This study first evaluated the effects and mechanisms of the preferential antiproliferation of fucoidan between oral cancer and non-malignant oral cells (S–G). In a 48 h MTS assay, fucoidan showed higher antiproliferation in response to five types of oral cancer cells, but not S–G cells, demonstrating preferential antiproliferation of oral cancer cells. Oral cancer cells (Ca9-22 and CAL 27) showing high sensitivity to fucoidan were selected to explore the antiproliferation mechanism compared to S–G cells. Fucoidan showed subG1 accumulation and an annexin V increase in apoptosis, accompanied by caspase 8, 9, and 3 activations in oral cancer cells, but not in S–G cells. Fucoidan increased reactive oxygen species and mitochondrial superoxide levels and decreased cellular glutathione in oral cancer cells compared with S–G cells. These oxidative stress effects were attributed to the downregulation of antioxidant signaling genes (NRF2, TXN, and HMOX1) in oral cancer cells rather than S–G cells. Fucoidan showed DNA damage-inducible effects (γH2AX and 8-hydroxy-2-deoxyguanosine) in oral cancer cells but not in S–G cells. Accordingly, these preferential changes in oral cancer but not in non-malignant cells contribute to the preferential antiproliferation mechanism of fucoidan. Furthermore, these changes were reverted by pretreatment with the antioxidant N-acetylcysteine. Therefore, for the first time, this study provides a detailed understanding of the preferential antiproliferation effects and mechanisms of fucoidan in oral cancer cells.

Polysaccharides with Antitumor Effect in Breast Cancer: A Systematic Review of Non-Clinical Studies

Purpose: To review the effects of polysaccharides and their proposed mechanisms of action in breast cancer experimental models. Data sources, selection, and extraction: Articles were selected by using PubMed, ScienceDirect, Scopus, and Medline, assessed from 1 May 2019 to 1 July 2020. The systematic review was registered in the International Prospective Register of Systematic Reviews (Prospero) under the number CRD42020169103. Results: Most of the studies explore algae polysaccharides (43.2%), followed by mushrooms (13.5%), plants (13.5%), fruits (10.8%), fungus (2.7%), bacteria, (2.7%), and sea animals (2.7%). A total of 8.1% investigated only in vitro models, 62.1% evaluated only in vivo models, and 29.7% evaluated in vitro and in vivo models. The mechanism of action involves apoptosis, inhibition of cellular proliferation, angiogenesis, and antimetastatic effects through multiple pathways. Conclusions: Findings included here support further investigations on the anti-tumor effect of polysaccharides. Some polysaccharides, such as fucoidan and β-glucans, deserve detailed and structured studies aiming at translational research on breast tumors, since they are already used in the clinical practice of other proposals of human health.

Cytotoxicity of Seaweed Compounds, Alone or Combined to Reference Drugs, against Breast Cell Lines Cultured in 2D and 3D

Seaweed bioactive compounds have shown anticancer activities in in vitro and in vivo studies. However, tests remain limited, with conflicting results, and effects in combination with anticancer drugs are even scarcer. Here, the cytotoxic effects of five seaweed compounds (astaxanthin, fucoidan, fucosterol, laminarin, and phloroglucinol) were tested alone and in combination with anticancer drugs (cisplatin-Cis; and doxorubicin-Dox), in breast cell lines (three breast cancer (BC) subtypes and one non-tumoral). The combinations revealed situations where seaweed compounds presented potentiation or inhibition of the drugs' cytotoxicity, without a specific pattern, varying according to the cell line, concentration used for the combination, and drug. Fucosterol was the most promising compound, since: (i) it alone had the highest cytotoxicity at low concentrations against the BC lines without affecting the non-tumoral line; and (ii) in combination (at non-cytotoxic concentration), it potentiated Dox cytotoxicity in the triple-negative BC cell line. Using a comparative approach, monolayer versus 3D cultures, further investigation assessed effects on cell viability and proliferation, morphology, and immunocytochemistry targets. The cytotoxic and antiproliferative effects in monolayer were not observed in 3D, corroborating that cells in 3D culture are more resistant to treatments, and reinforcing the use of more complex models for drug screening and a multi-approach that should include histological and ICC analysis.

The Development of Hyaluronan/Fucoidan-Based Nanoparticles as Macrophages Targeting an Epigallocatechin-3-Gallate Delivery System

The aim of this study was to develop a macrophage-targeted nanoparticle composed of hyaluronan/fucoidan complexes with polyethylene glycol-gelatin to encapsulate and deliver epigallocatechin-3-gallate (EGCG), a compound that can regulate macrophage activation and pro-inflammatory mediator production. We show that our nanoparticles can successfully bond to macrophages and deliver more EGCG than an EGCG solution treatment, confirming the anti-inflammatory effects of these nanoparticles in lipopolysaccharide-stimulated macrophages. The prepared nanoparticles were established with a small mean particle size (217.00 ± 14.00 nm), an acceptable polydispersity index (0.28 ± 0.07), an acceptable zeta potential value (-33.60 ± 1.30 mV), and a high EGCG loading efficiency (52.08% ± 5.37%). The targeting abilities of CD44 binding were increased as the hyaluronan concentration increased and decreased by adding a competitor CD44 antibody. Moreover, we found that fucoidan treatment significantly reduced macrophage migration after lipopolysaccharide treatment in a dose-responsive manner. In summary, we successfully created macrophage-targeted nanoparticles for effective targeted delivery of EGCG, which should aid in the development of future anti-inflammatory drugs against macrophage-related diseases.

Fucoidan Inhibits NLRP3 Inflammasome Activation by Enhancing p62/SQSTM1-Dependent Selective Autophagy to Alleviate Atherosclerosis

NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation contributes to the progression of atherosclerosis, and autophagy inhibits inflammasome activation by targeting macrophages. We investigated whether fucoidan, a marine sulfated polysaccharide derived from brown seaweeds, could reduce NLRP3 inflammasome activation by enhancing sequestosome 1 (p62/SQSTM1)-dependent selective autophagy to alleviate atherosclerosis in high-fat-fed ApoE-/- mice with partial carotid ligation and differentiated THP-1 cells incubated with oxidized low-density lipoprotein (oxLDL). Fucoidan significantly ameliorated lipid accumulation, attenuated progression of carotid atherosclerotic plaques, deregulated the expression of NLRP3 inflammasome, autophagy receptor p62, and upregulated microtubule-associated protein light chain 3 (LC3)-II/I levels. Transmission electron microscopy and GFP-RFP-LC3 lentivirus transfection further demonstrated that fucoidan could activate autophagy. Mechanistically, fucoidan remarkably inhibited NLRP3 inflammasome activation, which was mostly dependent on autophagy. The inhibitory effects of fucoidan on NLRP3 inflammasome were enhanced by autophagy activator rapamycin (Rapa) and alleviated by autophagy inhibitor 3-methyladenine (3-MA). Fucoidan promoted the colocalization of NLRP3 and p62. Knockdown of p62 and ATG5 by small interfering RNA significantly reduced the inhibitory effects of fucoidan treatment on NLRP3 inflammasome. The data suggest that fucoidan can inhibit NLRP3 inflammasome activation by enhancing p62/SQSTM1-dependent selective autophagy to alleviate atherosclerosis.

Fucoidan from Laminaria japonica exerts antitumor effects on angiogenesis and micrometastasis in triple-negative breast cancer cells

Fucoidan is a fucose-rich polysaccharide that has gained attention for its various anticancer properties. However, the effect and underlying mechanism of fucoidan on triple-negative breast cancer (TNBC) are still unknown. Herein, we investigated the anticancer potential of fucoidan from Laminaria japonica. We found that fucoidan showed modest antiproliferative activity against TNBC cells, while it effectively reduced migratory and invasive capacities. Mechanistically, fucoidan suppressed activation of MAPK and PI3K followed by inhibition of AP-1 and NF-κB signaling in TNBC. Additionally, fucoidan downregulated expressions of proangiogenic factors in TNBC cells, and fucoidan blocked tumor-elicited tube formation by human umbilical vascular endothelial cells (HUVECs). We also observed that fucoidan blocked tumor adhesion and invasion towards HUVECs. Surprisingly, fucoidan robustly suppressed tube formation on HUVECs. Moreover, fucoidan inhibited in vivo angiogenesis and micrometastasis in a transgenic zebrafish model. Together, L. japonica fucoidan exhibits potent antitumor effects by its attenuation of invasiveness and proangiogenesis in TNBC.

Upregulation of SHIP2 participates in the development of breast cancer via promoting Wnt/β-catenin signaling

Purpose

Src homology 2-containing inositol 5-phosphatase 2 (SHIP2) gene is associated with arthrosclerosis, gastric cancer and diabetes. In this study, we revealed that overexpression of SHIP2 is closely implicated with the development of breast cancer (BC).

Methods

The BC tissue and adjacent cancerous tissue were obtained from BC patients who had underwent mastectomy. BC cells with either overexpression or knockdown of SHIP2 were analyzed to determine cell proliferation, migration, invasion and apoptosis using the CCK-8 assay, colony formation assay, scratch assay, transwell assay and flow cytometry, respectively. A rat BC xenograft model was constructed to explore the role of SHIP2 on tumor growth in vivo.

Results

The expression levels of SHIP2 in BC tissues and cells were significantly higher than those in adjacent tissues and normal breast cells, respectively. Silencing SHIP2 suppressed BC cells proliferation and promoted apoptosis. Overexpression of SHIP2 enhanced the cells migration/invasion in BC. Moreover, SHIP2 participated in the Wnt/β-catenin pathway by regulating GSK-3β and its downstream genes. β-Catenin activator LiCl could significantly eliminate the effect of si-SHIP2 on BC cells. Moreover, overexpression of SHIP2 increased tumor volume and weight in rat model, and Wnt/β-catenin pathway inhibitor ICG001 reversed the promoting effect of SHIP2 on tumorigenesis.

Conclusion

Upregulation of SHIP2 could increase the migration, invasion, proliferation, and decrease apoptosis in BC cells. Moreover, SHIP2 participated in the progression of BC via activating the Wnt/β-catenin pathway.

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.

Associations among dietary seaweed intake, c-MYC rs6983267 polymorphism, and risk of colorectal cancer in a Korean population: a case-control study

PURPOSE

The effects of seaweed compounds have been studied in relation to colorectal cancer (CRC) based on their ability to modulate carcinogen metabolism in vivo and in vitro. However, no epidemiological studies on the interaction between edible seaweed and genetic variants relevant to CRC have been reported. This study examined the associations among dietary seaweed intake (gim, miyeok, and dashima), single-nucleotide polymorphisms (SNPs; rs6983267, rs7014346, and rs719725), and CRC risk in a Korean population.

METHODS

The participants comprised 923 CRC patients and 1846 controls who visited the National Cancer Center Korea. We used a Semiquantitative Food Frequency Questionnaire and genotyped SNPs using genomic DNA samples.

RESULTS

The intake of total seaweed, miyeok, and dashima showed a significant inverse association with CRC risk after adjusting for potential confounding factors (total seaweed odds ratio (OR) [95% CI] = 0.65 [0.50-0.85], P for trend < 0.001; miyeok = 0.82 [0.62-1.09], P for trend < 0.05; dashima = 0.58 [0.44-0.76], P for trend < 0.001, highest vs. lowest tertile). We confirmed that the homozygous T/T allele of rs6983267 c-MYC indicated an interaction between dietary seaweed intake and both overall CRC and rectal cancer (CRC OR [95% CI] = 0.52 [0.34-0.81], P for interaction = 0.015; rectal cancer = 0.45 [0.25-0.79], P for interaction = 0.007, T/T carriers with high total seaweed intake vs. T/T carriers with low total seaweed intake).

CONCLUSIONS

This study provides evidence of the effect of dietary seaweed intake on CRC risk with respect to c-MYC gene variants.

miR-107 Enhances the Sensitivity of Breast Cancer Cells to Paclitaxel

Breast cancer remains the most commonly diagnosed cancer in Chinese women. Paclitaxel (PTX) is a chemotherapy medication used to treat breast cancer patients. However, a side effect of paclitaxel is the severe drug resistance. Previous studies demonstrated that dysregulation of microRNAs could regulate sensitivity to paclitaxel in breast cancer. Here, the present study aimed to lucubrate the underlying mechanisms of miR-107 in regulating the sensitivity of breast cancer cells to PTX. The results demonstrated that miR-107 was down-regulated in breast cancer tumor tissues, while TPD52 was significantly up-regulated compared with the non-tumor adjacent tissues. After confirming that TPD52 may be a major target of miR-107 via a dual-luciferase reporter assay, the western blot and RT-qPCR assays further demonstrated that miR-107 may reduce the expression level of TPD52 as well. In addition, miR-107 may prominently enhance PTX induced reduction of cell viability and the promotion of cell apoptosis in breast cancer, and the variation could be reversed by co-transfected with pcDNA3.1-TPD52. Finally, miR-107 could further reduce the decreased expression of TPD52, Wnt1, β-catenin and cyclin D1 that was induced by PTX in both mRNA and protein levels, which were rescued by pcDNA3.1-TPD52 indicating that miR-107 regulated breast cancer cell sensitivity to PTX may be targeting TPD52 through Wnt/β-catenin signaling pathway.

Fucoidan inhibits epithelial-to-mesenchymal transition via regulation of the HIF-1α pathway in mammary cancer cells under hypoxia

This study examined the effects of fucoidan on epithelial-to-mesenchymal transition (EMT) in a human triple-negative breast cancer (TNBC) cell line in a hypoxic microenvironment. Transwell and wound-healing assays were performed to analyze the invasion and migration of MDA-MB-231 human mammary cancer cells, respectively. The expression levels of EMT markers and hypoxia-inducible factor-1α (HIF-1α) were detected through western blotting. Under hypoxia, fucoidan treatment inhibited proliferation of breast cancer cells. Fucoidan also suppressed the invasion and migration of MDA-MB-231 cells. Western blotting revealed that fucoidan treatment significantly reduced the protein expression levels of HIF-1α and HIF-1 target genes. Furthermore, the nuclear translocation and activity of HIF-1α were reduced. Fucoidan treatment significantly downregulated the expression levels of mesenchymal markers (N-cadherin and vimentin), but upregulated the expression levels of the epithelial markers zonula occludens-1 and E-cadherin. In addition, overexpression of HIF1-α protected cells from fucoidan-mediated suppression of migration and invasion. These data suggested that fucoidan may inhibit EMT in human TNBC cells via downregulation of the HIF1-α signaling pathway.

Low Molecular Weight Mannogalactofucans Derived from Undaria pinnatifida Induce Apoptotic Death of Human Prostate Cancer Cells In Vitro and In Vivo

Low molecular weight mannogalactofucans (LMMGFs) prepared by enzymatic degradation of high molecular weight Undaria galactofucan (MF) were evaluated for their anti-cancer effects against human prostate cancer. Correlation NMR and linkage analyses confirmed that LMMGFs consist mainly of α-fucose and β-galactose units: α-fucose units are 1,3-linked; β-galactose units are terminal, 1,3- and/or 1,6-linked; both sugars are partially sulphated, fucose at positions O-2 and/or O-4 and galactose at O-3. Mannose residue, as a minor sugar, presents as the 1,4-linked terminal units. LMMGFs more significantly induced cell cycle arrest at the G0/G1 phase and cell death via suppression of the Akt/GSK-3β/β-catenin pathway than MF in human PC-3 prostate cancer cells. LMMGFs upregulated mRNA expression of death receptor-5 (DR-5), the ratio of Bax to Bcl-2, the cleavage of caspases and PARP, the depolarisation of mitochondrial membrane potential, and ROS generation. LMMGFs (200-400 mg/kg) effectively reduced both tumour volume and size in a xenografted mouse model. These results demonstrated that LMMGFs attenuate the growth of human prostate cancer cells both in vitro and in vivo, suggesting that LMMGFs can be used as a potent functional ingredient in health-beneficial foods or as a therapeutic agent to prevent or treat androgen-independent human prostate cancer. Graphical Abstract.

Fucoidan Extracted from the New Zealand Undaria pinnatifida-Physicochemical Comparison against Five Other Fucoidans: Unique Low Molecular Weight Fraction Bioactivity in Breast Cancer Cell Lines

Fucoidan, the complex fucose-containing sulphated polysaccharide varies considerably in structure, composition, and bioactivity, depending on the source, species, seasonality, and extraction method. In this study, we examined five fucoidans extracted from the same seaweed species Undaria pinnatifida but from different geological locations, and compared them to the laboratory-grade fucoidan from Sigma (S). The five products differed in molecular composition. The amount of over 2 kDa low molecular weight fraction (LMWF) of the New Zealand crude fucoidan (S1) was larger than that of S, and this fraction was unique, compared to the other four fucoidans. The difference of molecular compositions between S and S1 explained our previous observation that S1 exhibited different anticancer profile in some cancer cell lines, compared with S. Since we observed this unique LMWF, we compared the cytotoxic effects of a LMWF and a high molecular weight fucoidan (HMWF) in two breast cancer cell lines-MCF-7 and MDA-MB-231. Results indicated that the molecular weight is a critical factor in determining the anti-cancer potential of fucoidan, from the New Zealand U. pinnatifida, as the LMWF exhibited a dose-dependent inhibition on the proliferation of breast cancer cells, significantly better than the HMWF, in both cell lines. A time-dependent inhibition was only observed in the MCF-7. Induction of caspase-dependent apoptosis was observed in the MDA-MB-231 cells, through the intrinsic apoptosis pathway alone, or with the extrinsic pathway. LMWF stimulated a dose-dependent NOS activation in the MDA-MB-231 cells. In conclusion, the fucoidan extracted from the New Zealand U. pinnatifida contains a unique LMWF, which could effectively inhibit the growth of breast cancer cell lines. Therefore, the LMWF from New Zealand U. pinnatifida could be used as a supplement cancer treatment.

Structural characterization and antitumor effects of fucoidans from brown algae Kjellmaniella crassifolia farmed in northern China

Brown alga-derived fucoidan has been proven to have a variety of bioactivities. To explore the antitumor effect of fucoidan, Kjellmaniella crassifolia (farmed in Dalian, China)was enzymatically digested to obtain the crude extract (F), which was further separated into three fractions (F1, F2 and F3). The monosaccharide composition and structural characteristics of the isolated fractions were determined using high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR) and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. F1 is an acetylated galactofucan, and F2 consists of fucose, galactose, mannose and glucuronic acid. F3 has two components, an acetylated galactofucan and a pure sulfated fucan. F, F1 and F2 showed limited cytotoxicity against murine hepatocarcinoma Hca-F cells in vitro. Oral administration of F at a dose of 450 mg/kg d significantly inhibited lump growth in Hca-F-inoculated mice and led to upregulated FAS expression in tumor tissues compared to that of the control. F1 and F2 did not show competitive antineoplastic efficacy, as did the crude extract. Crude fucoidan could be a promising antitumor adjuvant. The origin of its efficacy may be the small molecules, such as phenols that attached to native fucoidan. This theory needs to be further confirmed.

The effect of fucoidan on intestinal flora and intestinal barrier function in rats with breast cancer

Recent research studies have shown that the intestinal flora are related to the occurrence and progress of breast cancer. This study investigates the effect of fucoidan on intestinal flora and intestinal barrier function in rats with 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancers. Sixty female Sprague-Dawley rats were randomly assigned to the control group, the model group, and the F1 and F2 groups, which were fed fucoidan at concentrations of 200 and 400 mg per kg bw (body weight), respectively. Intestinal histopathological analysis was performed and 16S rDNA high-throughput sequencing was used to provide an overview of the intestinal flora composition. The contents of d-lactic acid (d-LA), diamine oxidase (DAO) and endotoxin in plasma were detected by ELISA. Expression levels of the tight junction (TJ) proteins, phosphorylated p38 MAPK and ERK1/2 were measured using western blotting. Our results suggested that the intestinal wall of the model group was damaged. However, after fucoidan intervention, the villi were gradually restored. ELISA showed that the levels of plasma endotoxin, d-LA and DAO decreased in the F1 and F2 groups compared to those in the model group. Fucoidan treatment also increased the expressions of ZO-1, occludin, claudin-1 and claudin-8. Furthermore, the expression levels of phosphorylated p38 MAPK and ERK1/2 were upregulated in fucoidan treatment groups. The results of 16S rDNA high-throughput sequencing indicated that fucoidan increased the diversity of the intestinal microbiota and induced changes in microbial composition, with the increased Bacteroidetes/Firmicutes phylum ratio. In conclusion, the supplement of fucoidan could improve the fecal microbiota composition and repair the intestinal barrier function. The study suggested the use of fucoidan as an intestinal flora modulator for potential prevention of breast cancer.

Dose matters: Direct killing or immunoregulatory effects of natural polysaccharides in cancer treatment

Polysaccharides from natural resources possess anti-tumor activities for decades, but the efficacy of polysaccharides as the adjuvant drugs for cancer treatment at prescribed doses remains open for debate. In this review, molecular mechanisms involved in direct killing effects of polysaccharides, including apoptosis, cell cycle arrest and mitochondria/DNA damage were described. However, the concentrations/doses used to reach the direct killing effects are too high to be applicable. Polysaccharides can also exert anti-tumor effects through immunoregulation at lower doses, and the effects of polysaccharides on natural killer cells, dendritic cells and other lymphocytes for tumor destruction, along with the receptor recognition and downstream signaling pathways, were delineated. Unfortunately, the prescribed doses of polysaccharides are too low to stimulate immunoresponse, resulting in the failure of some clinical trials. Therefore, understanding the sophisticated mechanisms of the immunoregulatory function of natural polysaccharides with refined doses for clinical use will help the standardization of traditional medicine.

The Effect of Undaria pinnatifida Fucoidan on the Pharmacokinetics of Letrozole and Tamoxifen in Patients With Breast Cancer

BACKGROUND

Although the use of complementary and alternative medicines is widespread in cancer patients, clinical evidence of their benefits is sparse. Furthermore, while they are often assumed to be safe with regard to concurrent use of anticancer therapies, few studies have been carried out to investigate possible interactions. Fucoidans are a group of sulfated carbohydrates, derived from marine brown algae, which have long been used as dietary supplements due to their reported medicinal properties, including anticancer activity. The aim of this study was to investigate the effect of co-administration of fucoidan, derived from Undaria pinnatifida, on the pharmacokinetics of 2 commonly used hormonal therapies, letrozole and tamoxifen, in patients with breast cancer.

METHODS

This was an open label non-crossover study in patients with active malignancy taking letrozole or tamoxifen (n = 10 for each group). Patients took oral fucoidan, given in the form of Maritech extract, for a 3-week period (500 mg twice daily). Trough plasma concentrations of letrozole, tamoxifen, 4-hydroxytamoxifen, and endoxifen were measured using HPLC-CAD (high-performance liquid chromatography charged aerosol detector), at baseline and after concomitant administration with fucoidan.

RESULTS

No significant changes in steady-state plasma concentrations of letrozole, tamoxifen, or tamoxifen metabolites were detected after co-administration with fucoidan. In addition, no adverse effects of fucoidan were reported, and toxicity monitoring showed no significant differences in all parameters measured over the study period.

CONCLUSIONS

Administration of Undaria pinnatifida fucoidan had no significant effect on the steady-state trough concentrations of letrozole or tamoxifen and was well tolerated. These results suggest that fucoidan in the studied form and dosage could be taken concomitantly with letrozole and tamoxifen without the risk of clinically significant interactions.

Oligo-Fucoidan prevents IL-6 and CCL2 production and cooperates with p53 to suppress ATM signaling and tumor progression

Low-molecular-weight Fucoidan (Oligo-Fucoidan) is a sulfated polysaccharide that has a variety of biological effects and has also been shown to have beneficial health effects. However, the molecular mechanisms underlying the therapeutic effects of Oligo-Fucoidan in patients with cancer remain unclear. Using human colorectal cancer HCT116 cells with (p53^+/+) or without (p53^−/−) normal p53 expression, we found that Oligo-Fucoidan treatment reduces the occurrence of spontaneous DNA lesions. Etoposide induces double strand DNA breaks. Subsequent administration of Oligo-Fucoidan to etoposide-treated cells promotes p53 accumulation, p21 expression and significant decreases in ataxia-telangiectasia-mutated (ATM), checkpoint kinase 1 (Chk1) and γ-H2AX phosphorylation in p53^+/+ cells compared with p53^−/− cells. Similarly, co-administration of Oligo-Fucoidan with etoposide inhibits ATM, Chk1 and γ-H2AX phosphorylation, particularly in the presence of p53. Furthermore, Oligo-Fucoidan supplementation increases cancer cell death and attenuates the adverse effects induced by etoposide that decreases production of the pro-inflammatory cytokine IL-6 and chemokine CCL2/MCP-1. Importantly, Oligo-Fucoidan decreases the tumor-promoting M2 macrophages in microenvironment as well as collaborates with p53 and works in combination with etoposide to prevent HCT116 tumorigenicity. Our results first demonstrate that p53 enables Oligo-Fucoidan to effectively inhibit tumor progression, and Oligo-Fucoidan minimizes the side effects of chemotherapy and alters tumor microenvironment.

Induction of p53-Independent Apoptosis and G1 Cell Cycle Arrest by Fucoidan in HCT116 Human Colorectal Carcinoma Cells

It is well known that fucoidan, a natural sulfated polysaccharide present in various brown algae, mediates anticancer effects through the induction of cell cycle arrest and apoptosis. Nevertheless, the role of tumor suppressor p53 in the mechanism action of fucoidan remains unclear. Here, we investigated the anticancer effect of fucoidan on two p53 isogenic HCT116 (p53+/+ and p53-/-) cell lines. Our results showed that inhibition of cell viability, induction of apoptosis and DNA damage by treatment with fucoidan were similar in two cell lines. Flow cytometric analysis revealed that fucoidan resulted in G1 arrest in the cell cycle progression, which correlated with the inhibition of phosphorylation of retinoblastoma protein (pRB) and concomitant association of pRB with the transcription factor E2Fs. Furthermore, treatment with fucoidan obviously upregulated the expression of cyclin-dependent kinase (CDK) inhibitors, such as p21WAF1/CIP1 and p27KIP1, which was paralleled by an enhanced binding with CDK2 and CDK4. These events also commonly occurred in both cell lines, suggesting that fucoidan triggered G1 arrest and apoptosis in HCT116 cells by a p53-independent mechanism. Thus, given that most tumors exhibit functional p53 inactivation, fucoidan could be a possible therapeutic option for cancer treatment regardless of the p53 status.

RNAi-mediated gene silencing of vascular endothelial growth factor C suppresses growth and induces apoptosis in mouse breast cancer in vitro and in vivo

Vascular endothelial cell growth factor (VEGF)-C promotes tumorigenesis by allowing lymph node metastasis and lymphangiogenesis, among other actions. RNA interference (RNAi) is a novel technique for suppressing target gene expression and may increase the effectiveness of cancer treatments. The present study assessed the influence of VEGF-C RNAi on the apoptosis and proliferation of mouse breast cancer cells in vitro and in vivo. A total of three pairs of small interfering RNA (siRNA) targeting mouse VEGF-C were designed and synthesized prior to transfection into 4T1 cells via a liposomal approach. Reverse transcription polymerase chain reaction, western blot analysis, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Hoechst 33258 staining and flow cytometry were performed in vitro to analyze VEGF-C expression, cleaved caspase-3 protein expression and 4T1 cell proliferation and apoptosis. Experiments were also conducted in vivo on BALB/c mice with breast cancer. Tumor weight and volume were measured and the number of apoptotic cells in tumor tissues was assessed by a TUNEL assay. Immunohistochemical assays and an enzyme-linked immunosorbent assay were used to measure the expression of VEGF-C in tumor tissues. The results demonstrated that the three pairs of siRNA, particularly siV2, significantly reduced VEGF-C mRNA and protein levels in 4T1 cells. siV2 was deemed to be the most efficient siRNA and therefore was selected to be used in subsequent experiments. Furthermore, in vitro studies indicated that VEGF-C RNAi significantly decreased cell growth, induced apoptosis and upregulated the expression of cleaved caspase-3 protein. Tumor weight and volume in breast cancer in vivo models was reduced by the intratumoral injection of siV2. Antitumor efficacy was associated with decreased VEGF-C expression and increased induction of apoptosis. The present study therefore indicated that VEGF-C RNAi inhibited mouse breast cancer growth in vitro and in vivo and that it may be a novel targeted therapy for breast cancer.

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.

Downregulation of survivin expression exerts antitumoral effects on mouse breast cancer cells in vitro and in vivo

Metastasis constantly occurs in the majority of cases of primary breast cancer at late stage or following surgical treatment. Survivin, a member of the inhibitor of apoptosis protein family, has long been recognized as a promising anticancer target, but its antitumor effects remain largely unexplored. In order to elucidate the role of survivin in breast cancer metastasis, short interfering RNA (siRNA) was used in the present study to specifically downregulate survivin expression in the murine breast cancer cell line 4T1. The results demonstrated that blocking the expression of survivin by siRNA inhibited the proliferation, migration and invasion abilities of murine breast cancer cells in vitro. Vascular endothelial growth factor (VEGF)-C is a lymphatic endothelial cell-stimulating factor that may lead to the formation of lymphatic vessels in lymph nodes. In the present study, the inhibition of survivin by siRNA was able to reduce the overexpression of VEGF-C in 4T1 cells. Furthermore, intratumoral injections of the survivin-siRNA significantly inhibited the growth of orthotopically transplanted 4T1 tumors in vivo. In addition, the number of pulmonary metastases and the microlymphatic vessel density were significantly reduced in vivo, following transfection with survivin-siRNA. The results of the present study suggested that the Akt/hypoxia-inducible factor-1α signaling pathway participates in the survivin-mediated downregulation of VEGF-C expression observed in breast cancer cells treated with survivin-siRNA. Therefore, the use of siRNA specifically targeting survivin may be a potential anticancer method in the future.

Fucoidan inhibits proliferation of the SKM-1 acute myeloid leukaemia cell line via the activation of apoptotic pathways and production of reactive oxygen species

Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and a high risk of progression to acute myeloid leukaemia (AML). Fucoidan, a complex sulphated polysaccharide isolated from the cell wall of brown seaweeds, has recently attracted attention for its multiple biological activities and its potential as a novel candidate for cancer therapy. In the present study, the anti‑cancer activity of fucoidan was investigated in the MDS/AML cell line SKM‑1. Fucoidan inhibited proliferation, induced apoptosis and caused G1-phase arrest of the cell cycle in SKM‑1 cells as determined by a cell counting kit 8 assay and flow cytometry. Furthermore, reverse transcription quantitative polymerase chain reaction and western blot analyses indicated that treatment with fucoidan (100 µg/ml for 48 h) activated Fas and caspase‑8 in SKM‑1 cells, which are critical for the extrinsic apoptotic pathway; furthermore, caspase‑9 was activated via decreases in phosphoinositide-3 kinase/Akt signaling as indicated by reduced levels of phosphorylated Akt, suggesting the involvement of the intrinsic apoptotic pathway. In addition, fucoidan treatment of SKM‑1 cells resulted in the generation of reactive oxygen species (ROS) as determined by staining with dichloro-dihydro-fluorescein diacetate. These results suggested that the mechanisms of the anti‑cancer effects of fucoidan in SKM‑1 are closely associated with cell cycle arrest and apoptotic cell death, which partly attributed to the activation of apoptotic pathways and accumulation of intracellular ROS. Our results demonstrated that Fucoidan inhibits proliferation and induces the apoptosis of SKM‑1 cells, which provides substantial therapeutic potential for MDS treatment.

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.

In vivo antitumor and antimetastatic effects of flavokawain B in 4T1 breast cancer cell-challenged mice

Flavokawain B (FKB) is a naturally occurring chalcone that can be isolated through the root extracts of the kava-kava plant (Piper methysticum). It can also be synthesized chemically to increase the yield. This compound is a promising candidate as a biological agent, as it is reported to be involved in a wide range of biological activities. Furthermore, FKB was reported to have antitumorigenic effects in several cancer cell lines in vitro. However, the in vivo antitumor effects of FKB have not been reported on yet. Breast cancer is one of the major causes of cancer-related deaths in the world today. Any potential treatment should not only impede the growth of the tumor, but also modulate the immune system efficiently and inhibit the formation of secondary tumors. As presented in our study, FKB induced apoptosis in 4T1 tumors in vivo, as evidenced by the terminal deoxynucleotidyl transferase dUTP nick end labeling and hematoxylin and eosin staining of the tumor. FKB also regulated the immune system by increasing both helper and cytolytic T-cell and natural killer cell populations. In addition, FKB also enhanced the levels of interleukin 2 and interferon gamma but suppressed interleukin 1B. Apart from that, FKB was also found to inhibit metastasis, as evaluated by clonogenic assay, bone marrow smearing assay, real-time polymerase chain reaction, Western blot, and proteome profiler analysis. All in all, FKB may serve as a promising anticancer agent, especially in treating breast cancer.

Fucoidan induces cancer cell apoptosis by modulating the endoplasmic reticulum stress cascades

BACKGROUND

Cancer metastasis is the main cause leading to disease recurrence and high mortality in cancer patients. Therefore, inhibiting metastasis process or killing metastatic cancer cells by inducing apoptosis is of clinical importance in improving cancer patient survival. Previous studies revealed that fucoidan, a fucose-rich polysaccharide isolated from marine brown alga, is a promising natural product with significant anti-cancer activity. However, little is known about the role of endoplasmic reticulum (ER) stress in fucoidan-induced cell apoptosis.

PRINCIPAL FINDINGS

We reported that fucoidan treatment inhibits cell growth and induces apoptosis in cancer cells. Fucoidan treatments resulted in down-regulation of the glucose regulated protein 78 (GRP78) in the metastatic MDA-MB-231 breast cancer cells, and of the ER protein 29 (ERp29) in the metastatic HCT116 colon cancer cells. However, fucoidan treatment promoted ER Ca2+-dependent calmodulin-dependent kinase II (CaMKII) phosphorylation, Bcl-associated X protein (Bax) and caspase 12 expression in MDA-MB-231 cells, but not in HCT116 cells. In both types of cancer cells, fucoidan activated the phosphorylation of eukaryotic initiation factor 2 alpha (p-eIF2α)\CCAAT/enhancer binding protein homologous protein (CHOP) pro-apoptotic cascade and inhibited the phosphorylation of inositol-requiring kinase 1 (p-IRE-1)\X-box binding proteins 1 splicing (XBP-1s) pro-survival cascade. Furthermore, CHOP knockdown prevented DNA damage and cell death induced by fucoidan.

CONCLUSION/SIGNIFICANCE

Fucoidan exerts its anti-tumor function by modulating ER stress cascades. Contribution of ER stress to the fucoidan-induced cell apoptosis augments our understanding of the molecular mechanisms underlying its anti-tumour activity and provides evidence for the therapeutic application of fucoidan in cancer.

Fucoidan inhibits the proliferation of human urinary bladder cancer T24 cells by blocking cell cycle progression and inducing apoptosis

Although fucoidan has been shown to exert anticancer activity against several types of cancer cell lines, no reports have explored fucoidan-affected cell growth in human urinary bladder cancer cells. In this study, we investigated the anti-proliferative effects of fucoidan in human bladder cancer T24 cells. Our results indicated that fucoidan decreased the viability of T24 cells through the induction of G1 arrest and apoptosis. Fucoidan-induced G1 arrest is associated with the enhanced expression of the Cdk inhibitor p21WAF1/CIP1 and dephosphorylation of the pRB along with enhanced binding of p21 to Cdk4/6 as well as pRB to the transcription factor E2Fs. Further investigations showed the loss of mitochondrial membrane potential and the release of cytochrome c from mitochondria to cytosol, proving mitochondrial dysfunction upon fucoidan treatment with a corresponding increase in the Bax/Bcl-2 expression ratio. Fucoidan-triggered apoptosis was also accompanied by the up-regulation of Fas and truncated Bid as well as the sequential activation of caspase-8. Furthermore, a significant increased activation of caspase-9/-3 was detected in response to fucoidan treatment with the decreased expression of IAPs and degradation of PARP, whereas a pan-caspase inhibitor significantly suppressed apoptosis and rescued the cell viability reduction. In conclusion, these observations suggest that fucoidan attenuates G1-S phase cell cycle progression and serves as an important mediator of crosstalk between caspase-dependent intrinsic and extrinsic apoptotic pathways in T24 cells.

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.