PDZ-binding kinase/T-LAK cell-originated protein kinase is a target of the fucoidan from brown alga Fucus evanescens in the prevention of EGF-induced neoplastic cell transformation and colon cancer growth

A review on marine source as anticancer agents

This review investigates the potential of natural compounds obtained from marine sources for the treatment of cancer. The oceans are believed to contain physiologically active compounds, such as alkaloids, nucleosides, macrolides, and polyketides, which have shown promising effects in slowing human tumor cells both in vivo and in vitro. Various marine species, including algae, mollusks, actinomycetes, fungi, sponges, and soft corals, have been studied for their bioactive metabolites with diverse chemical structures. The review explores the therapeutic potential of various marine-derived substances and discusses their possible applications in cancer treatment.

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.

The Combined Metabolically Oriented Effect of Fucoidan from the Brown Alga Saccharina cichorioides and Its Carboxymethylated Derivative with 2-Deoxy-D-Glucose on Human Melanoma Cells

Melanoma is the most aggressive and treatment-resistant form of skin cancer. It is phenotypically characterized by aerobic glycolysis that provides higher proliferative rates and resistance to cell death. The glycolysis regulation in melanoma cells by means of effective metabolic modifiers represents a promising therapeutic opportunity. This work aimed to assess the metabolically oriented effect and mechanism of action of fucoidan from the brown alga Saccharina cichorioides (ScF) and its carboxymethylated derivative (ScFCM) in combination with 2-deoxy-D-glucose (2-DG) on the proliferation and colony formation of human melanoma cell lines SK-MEL-28, SK-MEL-5, and RPMI-7951. The metabolic profile of melanoma cells was determined by the glucose uptake and Lactate-GloTM assays. The effect of 2-DG, ScF, ScFCM, and their combination on the proliferation, colony formation, and activity of glycolytic enzymes was assessed by the MTS, soft agar, and Western blot methods, respectively. When applied separately, 2-DG (IC50 at 72 h = 8.7 mM), ScF (IC50 at 72 h > 800 µg/mL), and ScFCM (IC50 at 72 h = 573.9 μg/mL) inhibited the proliferation and colony formation of SK-MEL-28 cells to varying degrees. ScF or ScFCM enhanced the inhibiting effect of 2-DG at low, non-toxic concentrations via the downregulation of Glut 1, Hexokinase II, PKM2, LDHA, and pyruvate dehydrogenase activities. The obtained results emphasize the potential of the use of 2-DG in combination with algal fucoidan or its derivative as metabolic modifiers for inhibition of melanoma SK-MEL-28 cell proliferation.

The carboxymethylated derivative of laminaran from brown alga Saccharina cichorioides: Structure, anticancer and anti-invasive activities in 3D cell culture

Polysaccharides' derivatives are promising biologically active compounds for biotechnology, nutrition, industries, and are becoming increasingly important in medicine and pharmacy. Laminaran from brown alga Saccharina cichorioides (ScL) was chemically modified to obtain the carboxymethylated derivative (ScLCM) with improved structure and bioactivity. ScLCM was identified as (1 → 3)-β-D-glucan with -CH2-COOH groups at some positions 2, 4, and 6 of glucose residues. The anticancer activity of ScLCM was studied on the models of viability and invasion of 3D human melanoma SK-MEL-28, breast cancer T-47D, and colorectal carcinoma DLD-1 cells in comparison with native laminaran or its sulfated or aminated derivatives. ScLCM had the highest anticancer and anti-invasive effects among investigated polysaccharides. ScLCM significantly suppressed the viability and invasion of 3D SK-MEL-28 cells via the regulation of the activity of matrix metalloproteinase 9 (MMP 9) and protein kinases of ERK/MAPK signaling pathway. These findings may contribute to the reported anticancer effects of algal polysaccharides' derivatives.

Structure and chemopreventive activity of fucoidans from the brown alga Alaria angusta

Six fucoidan fractions were isolated from the brown alga Alaria angusta. Structures of enzymatic hydrolysis products of the fraction 1AaF2 (Fuc:Gal ~ 1:1; 33 % of sulfates) by fucanase from Wenyingzhuangia fucanilytica were studied by chemical and instrumental (NMR spectroscopy and mass-spectrometry) methods. It was shown that 1AaF2 consisted of two structurally different fucoidans: a sulfated 1,3;1,4-α-L-fucan and an enzyme-resistant sulfated and acetylated complex fucogalactan (Fuc:Gal ~ 1:2; 19 % of sulfates) 1AaF2_HMP containing extended 1,3-linked fucose and 1,3/1,4-linked galactose fragments (up to 5 residues). The fractions 1AaF2 and 1AaF2_HMP were a non-cytotoxic, possessed dose-dependent chemopreventive effect on EGF-induced neoplastic cell transformation of mouse normal epidermal JB6 Cl41 cells and inhibited the colony formation of human melanoma SK-MEL-28 cells.

Ex vivo treatment with fucoidan of mononuclear cells from SARS-CoV-2 infected patients

COVID-19 is a worldwide health emergency, therapy for this disease is based on antiviral drugs and immunomodulators, however, there is no treatment to effectively reduce the COVID-19 mortality rate. Fucoidan is a polysaccharide obtained from marine brown algae, with anti-inflammatory, antiviral, and immune-enhancing properties, thus, fucoidan may be used as an alternative treatment (complementary to prescribed medical therapy) for the recovery of COVID-19.  This work aimed to determine the effects of ex-vivo treatment with fucoidan on cytotoxicity, apoptosis, necrosis, and senescence, besides functional parameters of calcium flux and mitochondrial membrane potential (ΔΨm) on human peripheral blood mononuclear cells isolated from SARS-CoV-2 infected, recovered and healthy subjects. Data suggest that fucoidan does not exert cytotoxicity or senescence, however, it induces the increment of intracellular calcium flux. Additionally, fucoidan promotes recovery of ΔΨm in PBMCs from COVID-19 recovered females. Data suggest that fucoidan could ameliorate the immune response in COVID-19 patients.

Anti-colorectal cancer effects of seaweed-derived bioactive compounds

Seaweeds are classified as Chlorophyta, Rhodophyta, and Phaeophyta. They constitute a number of the most significant repositories of new therapeutic compounds for human use. Seaweed has been proven to possess diverse bioactive properties, which include anticancer properties. The present review focuses on colorectal cancer, which is a primary cause of cancer-related mortality in humans. In addition, it discusses various compounds derived from a series of seaweeds that have been shown to eradicate or slow the progression of cancer. Therapeutic compounds extracted from seaweed have shown activity against colorectal cancer. Furthermore, the mechanisms through which these compounds can induce apoptosis in vitro and in vivo were reviewed. This review emphasizes the potential utility of seaweeds as anticancer agents through the consideration of the capability of compounds present in seaweeds to fight against colorectal cancer.

TOPK Activation Exerts Protective Effects on Cisplatin-induced Acute Kidney Injury

OBJECTIVE

T-LAK-cell-originated protein kinase (TOPK), a PSD95-Disc large-ZO1 (PDZ) binding kinase (PBK), is a novel member of the mitogen-activated protein kinase (MAPK) family. Studies have shown that TOPK plays a critical role in the function of tumor cells, including apoptosis and mitosis. However, little is known on the effect of TOPK in cisplatin-induced acute kidney injury (CP-AKI). This study aimed to investigate the role and mechanism of TOPK in CP-AKI.

METHODS

Cisplatin was administered to C57BL/6 mice and cultured kidney tubular epithelial cells (TECs) to establish the CP-AKI murine or cellular models. TECs were then stimulated with the specific inhibitor of TOPK OTS514 or transfected with the recombinant-activated plasmid TOPK-T9E to inhibit or activate TOPK. The TECs were treated with AKT inhibitor VIII following stimulation with OTS514 or cisplatin. Western blotting and flow cytometry were used to evaluate the cell cycle and apoptosis of TECs.

RESULTS

The analysis revealed that the TOPK activity was significantly suppressed by cisplatin, both in vivo and in vitro. Furthermore, the pharmacological inhibition of TOPK by OTS514, a specific inhibitor of TOPK, exacerbated the cisplatin-induced cell cycle arrest in the G2/M phase and apoptosis of cultured TECs. Moreover, the TOPK activation via the TOPK-T9E plasmid transfection could partially reverse the cell cycle arrest at the G2/M phase and apoptosis of cisplatin-treated TECs. In addition, AKT/protein kinase B (PKB), as a TOPK target protein, was inhibited by cisplatin in cultured TECs. The pharmaceutical inhibition of AKT further aggravated the apoptosis of TECs induced by cisplatin or TOPK inhibition. TOPK systematically mediated the apoptosis via the AKT pathway in the CP-AKI cell model.

CONCLUSION

These results indicate that TOPK activation protects against CP-AKI by ameliorating the G2/M cell cycle arrest and cell apoptosis.

Phosphorylation of PBK/TOPK Tyr74 by JAK2 promotes Burkitt lymphoma tumor growth

Burkitt lymphoma (BL), which is characterized by high invasiveness, is a subgroup of non-Hodgkin lymphoma. Although BL is regarded as a highly curable disease, especially for children, some patients unfortunately still do not respond adequately. The understanding of the etiology and molecular mechanisms of BL is still limited, and targeted therapies are still lacking. Here, we found that T-LAK cell-derived protein kinase (TOPK) and phosphorylated Janus kinase 2 (p-JAK2) are highly expressed in the tissues of BL patients. We report that TOPK directly binds to and is phosphorylated at Tyr74 by JAK2. Histone H3, one of the downstream targets of TOPK, is also phosphorylated in vivo and in vitro. Furthermore, we report that the phosphorylation of TOPK at Tyr74 by JAK2 plays a vital role in the proliferation of BL cells and promotes BL tumorigenesis in vivo. Phosphorylation of TOPK at Tyr74 by JAK2 enhances the stability of TOPK. Collectively, our results suggest that the JAK2/TOPK/histone H3 axis plays a key role in the proliferation of BL cells and BL tumorigenesis in vivo.

Effect of Fucoidan on the Mitochondrial Membrane Potential (ΔΨm) of Leukocytes from Patients with Active COVID-19 and Subjects That Recovered from SARS-CoV-2 Infection

Fucoidan is a polysaccharide obtained from marine brown algae, with anti-inflammatory, anti-viral, and immune-enhancing properties, thus, fucoidan may be used as an alternative treatment (complementary to prescribed medical therapy) for COVID-19 recovery. This work aimed to determine the ex-vivo effects of treatment with fucoidan (20 µg/mL) on mitochondrial membrane potential (ΔΨm, using a cationic cyanine dye, 3,3'-dihexyloxacarbocyanine iodide (DiOC6(3)) on human peripheral blood mononuclear cells (HPBMC) isolated from healthy control (HC) subjects, COVID-19 patients (C-19), and subjects that recently recovered from COVID-19 (R1, 40 ± 13 days after infection). In addition, ex-vivo treatment with fucoidan (20 and 50 µg/mL) was evaluated on ΔΨm loss induced by carbonyl cyanide 3-chlorophenylhydrazone (CCCP, 150 µM) in HPBMC isolated from healthy subjects (H) and recovered subjects at 11 months post-COVID-19 (R2, 335 ± 20 days after infection). Data indicate that SARS-CoV-2 infection induces HPBMC loss of ΔΨm, even 11 months after infection, however, fucoidan promotes recovery of ΔΨm in PBMCs from COVID-19 recovered subjects. Therefore, fucoidan may be a potential treatment to diminish long-term sequelae from COVID-19, using mitochondria as a therapeutic target for the recovery of cellular homeostasis.

The role of T-LAK cell-originated protein kinase in targeted cancer therapy

Targeted therapy has gradually become the first-line clinical tumor therapy due to its high specificity and low rate of side effects. TOPK (T-LAK cell-originated protein kinase), a MAP kinase, is highly expressed in various tumor tissues, while it is rarely expressed in normal tissues, with the exceptions of testicular germ cells and some fetal tissues. It can promote cancer cell proliferation and migration and is also related to drug resistance. Therefore, TOPK is considered a good therapeutic target. Moreover, a number of studies have shown that targeting TOPK can inhibit the proliferation of cancer cells and promote their apoptosis. Here, we discussed the biological functions of TOPK in cancer and summarized its tumor-related signaling network and known TOPK inhibitors. Finally, the role of TOPK in targeted cancer therapy was concluded, and future research directions for TOPK were assessed.

Recent Updates on Marine Cancer-Preventive Compounds

The natural compounds derived from marine organisms often exhibit unique chemical structures and potent biological activities. Cancer-preventive activity is one of the rather new activities that has emerged and been extensively studied over the last decades. This review summarizes the recent updates on the marine chemopreventive compounds covering the relevant literature published in 2013-2021 and following the previous comprehensive review by Stonik and Fedorov (Marine Drugs 2014, 12, 636-671). In the current article, only the molecules having an effect on malignant transformation (or related pathway and molecules), cancer stem cells, or carcinogen-induced in vivo tumor development were considered to be "true" cancer-preventive compounds and were, therefore, reviewed. Additionally, particular attention has been given to the molecular mechanisms of chemoprevention, executed by the reported marine compounds.

Combined Anticancer Effect of Sulfated Laminaran from the Brown Alga Alaria angusta and Polyhydroxysteroid Glycosides from the Starfish Protoreaster lincki on 3D Colorectal Carcinoma HCT 116 Cell Line

Colorectal cancer is one of the most frequent types of malignancy in the world. The search for new approaches of increasing the efficacy of cancer therapy is relevant. This work was aimed to study individual, combined anticancer effects, and molecular mechanism of action of sulfated laminaran AaLs of the brown alga Alaria angusta and protolinckiosides A (PL1), B (PL2), and linckoside L1 (L1) of the starfish Protoreaster lincki using a 3D cell culture model. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), soft agar, 3D spheroids invasion, and Western blotting assays were performed to determine the effect and mechanism of the action of investigated compounds or their combinations on proliferation, colony formation, and the invasion of 3D HCT 116 spheroids. AaLs, PL1, PL2, and L1 individually inhibited viability, colony growth, and the invasion of 3D HCT 116 spheroids in a variable degree with greater activity of linckoside L1. AaLs in combination with L1 exerted synergism of a combined anticancer effect through the inactivation of protein kinase B (AKT) kinase and, consequently, the induction of apoptosis via the regulation of proapoptotic/antiapoptotic proteins balance. The obtained data about the efficacy of the combined anticancer effect of a laminaran derivative of brown algae and polyhydroxysteroid glycosides of starfish open up prospects for the development of new therapeutic approaches for colorectal cancer treatment.

Fucoidan from brown algae Fucus evanescens potentiates the anti-proliferative efficacy of asterosaponins from starfish Asteropsis carinifera in 2D and 3D models of melanoma cells

This study was aimed to determine the efficacy of combination of fucoidan from the brown algae Fucus evanescens (FeF) or its derivatives with thornasteroside A (ThA) or asteropsiside A (AsA) from the starfish Asteropsis carinifera in combating human melanoma cells. In vitro MTS and soft agar methods were performed to determine effect of FeF, its derivatives, ThA, AsA or their combination on proliferation and colony formation of SK-MEL-28 cells in 2D and 3D culture. Desulfation of FeF, but not deacetylation, led decreasing of its Mw and anti-proliferative activity. The combinatorial effect of FeF with ThA and AsA depended on the sequences of treatment by compounds. There was additive anticancer effect of FeF with ThA or AsA during simultaneous treatment of cells. ThA and AsA were not active against SK-MEL-28 cells after their pre-treatment with FeF. Potential synergism of action was identified only when SK-MEL-28 cells were pre-treated with ThA and AsA and then by FeF. This process going through the regulation of MEK1/2/ERK1/2/MSK1 pathway and expression of the cell cycle proteins as determined by Western Blot. Thus, the combination of fucoidan with the asterosaponins opens up the prospects for the development of effective combined chemotherapeutic methods for melanoma treatment.

Pharmacological Activities of Sulfated Fucose-Rich Polysaccharides after Oral Administration: Perspectives for the Development of New Carbohydrate-Based Drugs

Marine organisms are a source of active biomolecules with immense therapeutic and nutraceutical potential. Sulfated fucose-rich polysaccharides are present in large quantities in these organisms with important pharmacological effects in several biological systems. These polysaccharides include sulfated fucan (as fucoidan) and fucosylated chondroitin sulfate. The development of these polysaccharides as new drugs involves several important steps, among them, demonstration of the effectiveness of these compounds after oral administration. The oral route is the more practical, comfortable and preferred by patients for long-term treatments. In the past 20 years, reports of various pharmacological effects of these polysaccharides orally administered in several animal experimental models and some trials in humans have sparked the possibility for the development of drugs based on sulfated polysaccharides and/or the use of these marine organisms as functional food. This review focuses on the main pharmacological effects of sulfated fucose-rich polysaccharides, with an emphasis on the antidislipidemic, immunomodulatory, antitumor, hypoglycemic and hemostatic effects.

Aminated laminaran from brown alga Saccharina cichorioides: Synthesis, structure, anticancer, and radiosensitizing potential in vitro

Laminarans are currently the focus of attention in regard to the selection of prospective agents for the prevention and treatment of cancer. Laminaran from Saccharina cichorioides was aminated to heighten anticancer and radiosensitizing activities and elucidate its molecular mode of action. Aminated laminaran, ScLNH2, was identified as 1,3-β-d-glucan with -CH2-CH(OH)-CH2-NH2 group at the C6 of branches. ScLNH2 selectively inhibited the viability and colony formation in the MDA-MB-231 cell line of triple negative breast cancer cells. ScLNH2 possessed synergism with radiation, resulting in a decreased number of colonies of MDA-MB-231 cells. The mechanism underling the radiosensitizing effect of ScLNH2 was associated with apoptosis induction via regulation of caspases 9 and 3 and PARP enzyme, preventing the repair of DNA damage in irradiated cells. These findings confirmed that combination therapy by aminated laminaran and radiation might play a role in the optimization of therapy for an aggressive form of human breast cancer.

Thomas O, Barraja P, Gaudêncio SP, Bertoni F. Marine Anticancer Agents: An Overview with a Particular Focus on Their Chemical Classes

The marine environment is a rich source of biologically active molecules for the treatment of human diseases, especially cancer. The adaptation to unique environmental conditions led marine organisms to evolve different pathways than their terrestrial counterparts, thus producing unique chemicals with a broad diversity and complexity. So far, more than 36,000 compounds have been isolated from marine micro- and macro-organisms including but not limited to fungi, bacteria, microalgae, macroalgae, sponges, corals, mollusks and tunicates, with hundreds of new marine natural products (MNPs) being discovered every year. Marine-based pharmaceuticals have started to impact modern pharmacology and different anti-cancer drugs derived from marine compounds have been approved for clinical use, such as: cytarabine, vidarabine, nelarabine (prodrug of ara-G), fludarabine phosphate (pro-drug of ara-A), trabectedin, eribulin mesylate, brentuximab vedotin, polatuzumab vedotin, enfortumab vedotin, belantamab mafodotin, plitidepsin, and lurbinectedin. This review focuses on the bioactive molecules derived from the marine environment with anticancer activity, discussing their families, origin, structural features and therapeutic use.

Inhibitory Effects of Laminaria japonica Fucoidans Against Noroviruses

Norovirus is the leading cause of nonbacterial foodborne disease outbreaks. Human noroviruses (HuNoVs) bind to histo-blood group antigens as the host receptor for infection. In this study, the inhibitory effects of fucoidans from brown algae, Laminaria japonica (LJ), Undaria pinnatifida and Undaria pinnatifida sporophyll, were evaluated against murine norovirus (MNoV), feline calicivirus (FCV) and HuNoV. Pretreatment of MNoV or FCV with the fucoidans at 1 mg/mL showed high antiviral activities, with 1.1 average log reductions of viral titers in plaque assays. They also showed significant inhibition on the binding of the P domains of HuNoV GII.4 and GII.17 to A- or O-type saliva and the LJ fucoidan was the most effective, reaching 54-72% inhibition at 1 mg/mL. In STAT1-/- mice infected with MNoV, oral administration of the LJ fucoidan, composed of mainly sulfated fucose and minor amounts of glucose and galactose, improved the survival rates of mice and significantly reduced the viral titers in their feces. Overall, these results provide the LJ fucoidan can be used to reduce NoV outbreaks.

Fucoidan Derived from Fucus vesiculosus Inhibits the Development of Human Ovarian Cancer via the Disturbance of Calcium Homeostasis, Endoplasmic Reticulum Stress, and Angiogenesis

Marine organisms are sources of several natural compounds with potential clinical use. However, only a few marine-based pharmaceuticals have been approved for use due to limited knowledge on their biological activities. Here, we identified the functional role of fucoidan extracted from Fucus vesiculosus on ovarian cancer. Fucoidan increased the death of ES-2 and OV-90 cells, through a reduction in proliferation, cell cycle arrest, releases of cytochrome c, reactive oxygen species (ROS) generation, and endoplasmic reticulum (ER) stress. Additionally, fucoidan increased the concentration of cytosolic and mitochondrial calcium in both cells. The decrease of cell proliferation was controlled by the inactivation of PI3K and MAPK signaling cascades in ES-2 and OV-90 cells. In a toxicity assay with normal zebrafish larvae, fucoidan did not induce toxicity, cardiotoxicity, development, kinesis, and apoptosis at different concentrations. However, it disrupted tumor formation and vascular development in a zebrafish xenograft model and angiogenesis transgenic (Tg, fli1-eGFP) model, respectively. Collectively, the results indicate that fucoidan may be a novel pharmaceutical for the management of human ovarian cancer.

Degraded fucoidan fractions and β-1,3-glucan sulfates inhibit CXCL12-induced Erk1/2 activation and chemotaxis in Burkitt lymphoma cells

Fucoidans are natural polysaccharides with pronounced antitumoral activities. Their modes of action include the antagonization of the chemokine CXCL12, which plays a central role in tumor development and metastasis. However, the usually high molecular mass (M_w) of fucoidans represents an obstacle to their medical application. We therefore investigated two series of degraded fucoidan fractions with regard to their CXCL12 binding and inhibition of CXCL12-induced effects in Raji cells. In addition, semisynthetic β-1,3-glucan sulfates were examined to get more information about the impact of M_w and degree of sulfation (DS). Degradation of the fucoidans from Saccharina latissima (S.l.-SP; 481-77.0 kDa) and Fucus vesiculosus (F.v.-SP; 38.2-20.6 kDa) did not affect the respective binding capacity to CXCL12. Both the M_w independence and the DS dependence were confirmed by the β-1,3-glucan sulfates having significantly higher affinity to CXCL12. The chemokine binding resulted in reduced CXCL12-induced Erk1/2 signaling and chemotaxis of Raji cells which was also independent of the M_w. Solely the oxidatively degraded fucoidan fraction displayed a significantly reduced chemotaxis inhibition. In conclusion, degradation of fucoidans to obtain biopharmaceutically more favorable M_w is possible without impairing their activities targeting CXCL12. Moreover, the β-1,3-glucan sulfates should also be considered as promising candidates for further development.

Off-target toxicity is a common mechanism of action of cancer drugs undergoing clinical trials

Ninety-seven percent of drug-indication pairs that are tested in clinical trials in oncology never advance to receive U.S. Food and Drug Administration approval. While lack of efficacy and dose-limiting toxicities are the most common causes of trial failure, the reason(s) why so many new drugs encounter these problems is not well understood. Using CRISPR-Cas9 mutagenesis, we investigated a set of cancer drugs and drug targets in various stages of clinical testing. We show that-contrary to previous reports obtained predominantly with RNA interference and small-molecule inhibitors-the proteins ostensibly targeted by these drugs are nonessential for cancer cell proliferation. Moreover, the efficacy of each drug that we tested was unaffected by the loss of its putative target, indicating that these compounds kill cells via off-target effects. By applying a genetic target-deconvolution strategy, we found that the mischaracterized anticancer agent OTS964 is actually a potent inhibitor of the cyclin-dependent kinase CDK11 and that multiple cancer types are addicted to CDK11 expression. We suggest that stringent genetic validation of the mechanism of action of cancer drugs in the preclinical setting may decrease the number of therapies tested in human patients that fail to provide any clinical benefit.

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.

Cell growth inhibition by 3-deoxysappanchalcone is mediated by directly targeting the TOPK signaling pathway in colon cancer

BACKGROUND

Colorectal cancer is one of the most common causes of cancer death worldwide. Unfortunately, chemotherapies are limited due to many complications and development of resistance and recurrence. The T-lymphokine-activated killer cell-originated protein kinase (TOPK) is highly expressed and activated in colon cancer, and plays an important role in inflammation, proliferation, and survival of cancer cells. Therefore, suppressing TOPK activity and its downstream signaling cascades is considered to be a rational therapeutic/preventive strategy against colon cancers.

PURPOSE

3-Deoxysappanchalcone (3-DSC), a component of Caesalpinia sappan L., is a natural oriental medicine. In this study, we investigated the effects of 3-DSC on colon cancer cell growth and elucidated its underlying molecular mechanism of targeting TOPK.

STUDY DESIGN AND METHODS

To evaluate the effects of 3-DSC against colon cancer, we performed cell proliferation assays, propidium iodide- and annexin V-staining analyses and Western blotting. Targeting TOPK by 3-DSC was identified by a kinase-binding assay and computational docking models.

RESULTS

3-DSC inhibited the kinase activity of TOPK, but not mitogen-activated protein kinase (MEK). The direct binding of 3-DSC with TOPK was explored using a computational docking model and binding assay in vitro and ex vivo. 3-DSC inhibited colon cancer cell proliferation and anchorage-independent cell growth, and induced G2/M cell cycle arrest and apoptosis. Treatment of colon cancer cells with 3-DSC induced expression of protein that are involved in cell cycle (cyclin B1) and apoptosis (cleaved-PARP, cleaved-caspase-3, and cleaved-caspase-7), and suppressed protein expressions of extracellular signal-regulated kinase (ERK)-1/2, ribosomal S6 kinase (RSK), and c-Jun, which are regulated by the upstream kinase, TOPK.

CONCLUSION

3-DSC suppresses colon cancer cell growth by directly targeting the TOPK- mediated signaling pathway.

Laminaran from brown alga Dictyota dichotoma and its sulfated derivative as radioprotectors and radiosensitizers in melanoma therapy

The laminarans are neutral water-soluble β-D-glucans of brown algae possessing potent immunomodulating, radioprotective, and anticancer activities. The aim of the present study was to investigate in vitro anticancer, radioprotective, and radiosensitizing activities of laminaran from brown alga Dictyota dichotoma and its sulfated derivative. The native and sulfated laminarans by themselves at non-toxic doses possessed significant anticancer activity against melanoma cells. Both polysaccharides protected normal epidermal cells, while only sulfated laminaran was able to sensitize melanoma cells to X-rays irradiation resulting in significant inhibition of cell proliferation, colony formation, and migration of cancer cells. The molecular mechanism of this action was related to the inhibition of MMP-2 and MMP-9 proteinases activity as well as down-regulation of kinases' phosphorylation of ERK1/2 signaling cascade. Taken together, the combination of sulfated derivative of laminaran from D. dichotoma with X-ray may serve as a potential treatment strategy for human melanoma.

Radiosensitizing effect of the fucoidan from brown alga Fucus evanescens and its derivative in human cancer cells

Fucoidan from brown alga Fucus evanescens and its product of enzymatic hydrolysis have precisely established structure and possess significant biological activities. The aim of present study was to determine radiosensitizing activity of fucoidan from brown alga F. evanescens and its derivative in human melanoma, breast adenocarcinoma, and colorectal carcinoma cell lines and elucidate mechanism of their action. The fucoidan from F. evanescens and its derivative had a comparable radiosensitizing activity and increased the inhibiting effect of X-ray radiation on proliferation and colony formation of human cancer cells, with significant inhibition of melanoma cells. The molecular mechanism of this action was associated with the induction of apoptosis by activating the initiator and effector caspases, suppressing the expression of the anti-apoptotic protein, and enhancing the fragmentation of DNA. The obtained data confirm the prospects of using fucoidan's derivative in combination with radiation therapy for the improvement of the schemes of cancer therapy.

Fucoidan Structure and Activity in Relation to Anti-Cancer Mechanisms

Fucoidan is a natural derived compound found in different species of brown algae and in some animals, that has gained attention for its anticancer properties. However, the exact mechanism of action is currently unknown. Therefore, this review will address fucoidans structure, the bioavailability, and all known different pathways affected by fucoidan, in order to formulate fucoidans structure and activity in relation to its anti-cancer mechanisms. The general bioactivity of fucoidan is difficult to establish due to factors like species-related structural diversity, growth conditions, and the extraction method. The main pathways influenced by fucoidan are the PI3K/AKT, the MAPK pathway, and the caspase pathway. PTEN seems to be important in the fucoidan-mediated effect on the AKT pathway. Furthermore, the interaction with VEGF, BMP, TGF-β, and estrogen receptors are discussed. Also, fucoidan as an adjunct seems to have beneficial effects, for both the enhanced effectiveness of chemotherapy and reduced toxicity in healthy cells. In conclusion, the multipotent character of fucoidan is promising in future anti-cancer treatment. However, there is a need for more specified studies of the structure⁻activity relationship of fucoidan from the most promising seaweed species.

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.

Investigation of Different Molecular Weight Fucoidan Fractions Derived from New Zealand Undaria pinnatifida in Combination with GroA Therapy in Prostate Cancer Cell Lines

Fucoidan, a sulfated polysaccharide extracted from brown seaweeds, has been shown to possess various antioxidant, anticoagulant, antiviral, and anticancer functions. In this study, we focused on low molecular weight fucoidan (LMWF) which was extracted from New Zealand Undaria pinnatifida, and investigated its anti-proliferative effects, combined with a quadruplex-forming oligonucleotide aptamer (GroA, AS1411), a powerful cell surface Nucleolin inhibitor, in prostate cancer cells. We examined LMWF (<10 kDa) and compared it with laboratory grade Fucoidan purchased from Sigma (FS), all extracted from the same seaweed species U. pinnatifida. We found that LMWF significantly improved the anti-proliferative effect of GroA, as it decreased cancer cell growth and viability and increased cell death. This research may provide the foundation for LMWF to be used against prostate cancers as a supplement therapy in combination with other therapeutic agents.

Phycochemical Constituents and Biological Activities of Fucus spp

Seaweeds are known to be a good supply of key nutrients including carbohydrates, protein, minerals, polyunsaturated lipids, as well as several other health-promoting compounds capable of acting on a wide spectrum of disorders and/or diseases. While these marine macroalgae are deeply rooted in the East Asian culture and dietary habits, their major application in Western countries has been in the phycocolloid industry. This scenario has however been gradually changing, since seaweed consumption is becoming more common worldwide. Among the numerous edible seaweeds, members of the genus Fucus have a high nutritional value and are considered good sources of dietary fibers and minerals, especially iodine. Additionally, their wealth of bioactive compounds such as fucoidan, phlorotannins, fucoxanthin and others make them strong candidates for multiple therapeutic applications (e.g., antioxidant, anti-inflammatory, anti-tumor, anti-obesity, anti-coagulant, anti-diabetes and others). This review presents an overview of the nutritional and phytochemical composition of Fucus spp., and their claimed biological activities, as well as the beneficial effects associated to their consumption. Furthermore, the use of Fucus seaweeds and/or their components as functional ingredients for formulation of novel and enhanced foods is also discussed.

Mitotic kinase PBK/TOPK as a therapeutic target for adult T‑cell leukemia/lymphoma

Adult T‑cell leukemia/lymphoma (ATLL) is a disorder involving human T-cell leukemia virus type 1 (HTLV‑1)-infected T‑cells characterized by increased clonal neoplastic proliferation. PDZ-binding kinase (PBK) [also known as T‑lymphokine-activated killer cell-originated protein kinase (TOPK)] is a serine/threonine kinase expressed in proliferative cells and is phosphorylated during mitosis. In this study, the expression and phosphorylation of PBK/TOPK were examined by western blot analysis and RT‑PCR. We found that PBK/TOPK was upregulated and phosphorylated in HTLV‑1-transformed T‑cell lines and ATLL‑derived T‑cell lines. Notably, CDK1/cyclin B1, which phosphorylates PBK/TOPK, was overexpressed in these cells. HTLV‑1 infection upregulated PBK/TOPK expression in peripheral blood mononuclear cells (PBMCs) in co-culture assays. The potent PBK/TOPK inhibitors, HI‑TOPK‑032, and fucoidan from brown algae, decreased the proliferation and viability of these cell lines in a dose‑dependent manner. By contrast, the effect of HI‑TOPK‑032 on PBMCs was less pronounced. Treatment with HI‑TOPK‑032 resulted in G1 cell cycle arrest, and decreased CDK6 expression and pRb phosphorylation, which are critical determinants of progression through the G1 phase. In addition, HI‑TOPK‑032 induced apoptosis, as evidenced by morphological changes, the cleavage of poly(ADP-ribose) polymerase with the activation of caspase‑3, -8 and -9, and an increase in the sub‑G1 cell population and APO2.7-positive cells. Moreover, HI‑TOPK‑032 inhibited the expression of cellular inhibitor of apoptosis 2 (c-IAP2), X-linked inhibitor of apoptosis protein (XIAP), survivin and myeloid cell leukemia‑1 (Mcl‑1), and induced the expression of Bak and interferon-induced protein with tetratricopeptide repeats (IFIT)1, 2 and 3. It is noteworthy that the use of this inhibitor led to the inhibition of the phosphorylation of IκB kinase (IKK)α, IKKβ, IκBα, phosphatase and tensin homolog (PTEN) and Akt, and to the decreased protein expression of JunB and JunD, suggesting that PBK/TOPK affects the nuclear factor-κB, Akt and activator protein‑1 signaling pathways. In vivo, the administration of HI‑TOPK‑032 suppressed tumor growth in an ATLL xenograft model. Thus, on the whole, this study on the identification and functional analysis of PBK/TOPK suggests that this kinase is a promising molecular target for ATLL treatment.

Fucoidan enhances the therapeutic potential of arsenic trioxide and all-trans retinoic acid in acute promyelocytic leukemia, in vitro and in vivo

The morbidity and mortality associated with current therapies for acute promyelocytic leukemia (APL) remain a significant clinical concern, despite improvements in patient survival. Consequently, the development of adjuvant therapies that increase efficacy while reducing morbidities is important. Reducing the concentration of the toxic drugs in adjuvant therapy has the potential to reduce unwanted side effects. Therefore, this study aimed to determine the synergistic effects of fucoidan, an anti-tumor agent, with current APL therapies.When the human APL cell line, NB4, was treated in vitro with fucoidan plus ATO and ATRA at therapeutic and sub-therapeutic doses, there was an increase in sub-G0/G1 cells, annexin V/PI-positive-apoptotic cells and DNA fragmentation. This reduction in proliferation and increase in apoptosis was accompanied by enhanced myeloid differentiation as indicated by an increased expression of CD11b. This was not observed with the AML cell line Kasumi-1, suggesting specificity for APL.In vivo treatment of APL-bearing mice with fucoidan+ATRA or fucoidan+ATO delayed tumor growth, induced differentiation and increased tumor volume doubling time. The differentiated APL cells derived from the excised tumor mass exhibited decreased CD44 expression in fucoidan+ATRA treated mice. This could translate to decreased cell migration in APL patients.Our findings provide evidence supporting the use of fucoidan as an adjuvant therapeutic agent in the treatment of APL.

The potential of brown-algae polysaccharides for the development of anticancer agents: An update on anticancer effects reported for fucoidan and laminaran

In recent decades, attention to cancer-preventive treatments and studies on the development of anticancer drugs have sharply increased owing to the increase in cancer-related death rates in every region of the world. However, due to the adverse effects of synthetic drugs, much attention has been given to the development of anticancer drugs from natural sources because of fewer side effects of natural compounds than those of synthetic drugs. Recent studies on compounds and crude extracts from marine algae have shown promising anticancer properties. Among those compounds, polysaccharides extracted from brown seaweeds play a principal role as anticancer agents. Especially, a number of studies have revealed that polysaccharides isolated from brown seaweeds, such as fucoidan and laminaran, have promising effects against different cancer cell types in vitro and in vivo. Herein, we reviewed in vitro and in vivo anticancer properties reported for fucoidan and laminaran toward various cancer cells from 2013 to 2016.

In vitro and in vivo anti-primary effusion lymphoma activities of fucoidan extracted from Cladosiphon okamuranus Tokida

Primary effusion lymphoma (PEL) caused by Kaposi's sarcoma-associated herpesvirus (KSHV) is characterized by lymphomatous effusion in body cavities and poor prognosis. There is still no effective treatment for PEL. Fucoidan, a major sulfated polysaccharide isolated from brown seaweeds, has an attractive array of bioactivities such as cancer inhibition. However, the effects of fucoidan on PEL cells remain unclear. We investigated the anti-PEL effects of fucoidan obtained from Cladosiphon okamuranus Tokida cultivated in Okinawa. Fucoidan dose-dependently inhibited the proliferation of KSHV-infected PEL cell lines, and provoked G1 cell cycle arrest, which was accompanied by CDK4 and CDK6 downregulation. Fucoidan also induced apoptosis of PEL cells through caspase-3, -8 and -9 activation; this occurred partly through the downregulation of anti-apoptotic Bcl-xL, Mcl-1 and XIAP proteins. Fucoidan also suppressed nuclear factor-κB, activator protein-1 (AP-1), and T-lymphokine-activated killer cell-originated protein kinase (TOPK) signaling pathways through inhibition of phosphorylation of IκBα and TOPK, and the expression of AP-1 family proteins, JunB and JunD. Oral administration of fucoidan effectively inhibited the development of PEL cells and ascites in a xenograft SCID mouse model, with minimal serious adverse effects. Notably, native fucoidan exhibited a more efficient anti-PEL effect than nanoparticle fucoidan. These preclinical findings highlight the anti-PEL actions of fucoidan, suggesting it could be potentially useful for the prevention and treatment of PEL.

The Inhibitory Activity of Luzonicosides from the Starfish Echinaster luzonicus against Human Melanoma Cells

Malignant melanoma is the most dangerous form of skin cancer, with a rapidly increasing incidence rate. Despite recent advances in melanoma research following the approval of several novel targeted and immuno-therapies, the majority of oncological patients will ultimately perish from the disease. Thus, new effective drugs are still required. Starfish steroid glycosides possess different biological activities, including antitumor activity. The current study focused on the determination of the in vitro inhibitory activity and the mechanism of action of cyclic steroid glycosides isolated from the starfish Echinaster luzonicus-luzonicoside A (LuzA) and luzonicoside D (LuzD)-in human melanoma RPMI-7951 and SK-Mel-28 cell lines. LuzA inhibited proliferation, the formation of colonies, and the migration of SK-Mel-28 cells significantly more than LuzD. Anti-cancer activity has been ascribed to cell cycle regulation and apoptosis induction. The molecular mechanism of action appears to be related to the regulation of the activity of cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP), along with Survivin, Bcl-2, p21 and cyclin D1 level. Overall, our findings support a potential anti-cancer efficacy of luzonicosides A and D on human melanoma cells.

The T-LAK Cell-originated Protein Kinase Signal Pathway Promotes Colorectal Cancer Metastasis

Approximately 90% of all cancer deaths arise from the metastatic dissemination of primary tumors. Metastasis is the most lethal attribute of colorectal cancer. New data regarding the molecules contributing to the metastatic phenotype, the pathways they control and the genes they regulate are very important for understanding the processes of metastasis prognosis and prevention in the clinic. The purpose of this study was to investigate the role of T-LAK cell-originated protein kinase (TOPK) in the promotion of colorectal cancer metastasis. TOPK is highly expressed in human metastatic colorectal cancer tissue compared with malignant adenocarcinoma. We identified p53-related protein kinase (PRPK) as a new substrate of TOPK. TOPK binds with and phosphorylates PRPK at Ser250 in vitro and ex vivo. This site plays a critical role in the function of PRPK. Cell lines stably expressing mutant PRPK (S250A), knockdown TOPK, knockdown PRPK or knockdown of both TOPK and PRPK significantly inhibited liver metastasis of human HCT116 colon cancer cells in a xenograft mouse model. Therefore, we conclude that TOPK directly promotes metastasis of colorectal cancer by modulating PRPK. Thus, these findings may assist in the prediction of prognosis or development of new therapeutic strategies against colon cancer.