Fucoidan-Supplemented Diet Potentiates Immune Checkpoint Blockage by Enhancing Antitumor Immunity

Strategies to enhance the therapeutic efficacy of anti-PD-1 antibody, anti-PD-L1 antibody and anti-CTLA-4 antibody in cancer therapy

Although immune checkpoint inhibitors (anti-PD-1 antibody, anti-PD-L1 antibody, and anti-CTLA-4 antibody) have displayed considerable success in the treatment of malignant tumors, the therapeutic effect is still unsatisfactory for a portion of patients. Therefore, it is imperative to develop strategies to enhance the effect of these ICIs. Increasing evidence strongly suggests that the key to this issue is to transform the tumor immune microenvironment from a state of no or low immune infiltration to a state of high immune infiltration and enhance the tumor cell-killing effect of T cells. Therefore, some combination strategies have been proposed and this review appraise a summary of 39 strategies aiming at enhancing the effectiveness of ICIs, which comprise combining 10 clinical approaches and 29 foundational research strategies. Moreover, this review improves the comprehensive understanding of combination therapy with ICIs and inspires novel ideas for tumor immunotherapy.

Anticancer Mechanism of Astragalus Polysaccharide and Its Application in Cancer Immunotherapy

Astragalus polysaccharide (APS) derived from A. membranaceus plays a crucial role in traditional Chinese medicine. These polysaccharides have shown antitumor effects and are considered safe. Thus, they have become increasingly important in cancer immunotherapy. APS can limit the spread of cancer by influencing immune cells, promoting cell death, triggering cancer cell autophagy, and impacting the tumor microenvironment. When used in combination with other therapies, APS can enhance treatment outcomes and reduce toxicity and side effects. APS combined with immune checkpoint inhibitors, relay cellular immunotherapy, and cancer vaccines have broadened the application of cancer immunotherapy and enhanced treatment effectiveness. By summarizing the research on APS in cancer immunotherapy over the past two decades, this review elaborates on the anticancer mechanism of APS and its use in cancer immunotherapy and clinical trials. Considering the multiple roles of APS, this review emphasizes the importance of using APS as an adjunct to cancer immunotherapy and compares other polysaccharides with APS. This discussion provides insights into the specific mechanism of action of APS, reveals the molecular targets of APS for developing effective clinical strategies, and highlights the wide application of APS in clinical cancer therapy in the future.

Fucoidan enhances the anti-tumor effect of anti-PD-1 immunotherapy by regulating gut microbiota

Currently, the clinical efficacy of anti-PD-1/PD-L1 monotherapy strategies against breast cancer is limited, and low response rates need to be improved. Gut microbiota plays a crucial role in the sensitization process of immunotherapy. As a natural dietary supplement, fucoidan has been reported to have immunomodulatory effects, while some studies have found that oral fucoidan may act as a potential prebiotic to modulate the gut microbiota. Therefore, this study investigated whether fucoidan could enhance the effects of anti-PD-1 monoclonal antibody antitumor immunotherapy by modulating gut microbiota and its metabolites. We found that the anti-tumor effect of the combination treatment was significantly enhanced, while fucoidan significantly improved the composition of the gut microbiota by increasing the number of potentially beneficial bacteria, such as Bifidobacterium, Faecalibaculum and Lactobacillus. Interference with the gut microbiota by antibiotics revealed impaired antitumor efficacy, confirming the necessity of gut microbiota in the antitumor effects of fucoidan in vivo. Metabolomics further revealed that fucoidan may have reversed the metabolic disturbances induced by the breast cancer model through tryptophan metabolism and glycerophospholipid metabolism pathways, with the most significant increase in the content of short-chain fatty acids, especially acetic and butyric acids. These modulations improved the function of effector T cells and suppressed Treg cell production. Thus, our findings suggest that fucoidan combined with the anti-PD-1 monoclonal antibody may be a novel strategy to sensitize breast cancer patients to anti-PD-1 monoclonal antibody immunotherapy. Meanwhile, the gut microbiota might serve as a new biomarker to predict the anti-PD-1 monoclonal antibody response to breast cancer immunotherapy.

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

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

The impact of microbiome dysbiosis on T cell function within the tumor microenvironment (TME)

Insights into the effect of the microbiome’s composition on immune cell function have recently been discerned and further characterized. Microbiome dysbiosis can result in functional alterations across immune cells, including those required for innate and adaptive immune responses to malignancies and immunotherapy treatment. Dysbiosis can yield changes in or elimination of metabolite secretions, such as short-chain fatty acids (SCFAs), from certain bacterial species that are believed to impact proper immune cell function. Such alterations within the tumor microenvironment (TME) can significantly affect T cell function and survival necessary for eliminating cancerous cells. Understanding these effects is essential to improve the immune system’s ability to fight malignancies and the subsequent efficacy of immunotherapies that rely on T cells. In this review, we assess typical T cell response to malignancies, classify the known impact of the microbiome and particular metabolites on T cells, discuss how dysbiosis can affect their function in the TME then further describe the impact of the microbiome on T cell-based immunotherapy treatment, with an emphasis on recent developments in the field. Understanding the impact of dysbiosis on T cell function within the TME can carry substantial implications for the design of immunotherapy treatments and further our understanding of factors that could impact how the immune system combats malignancies.

Relevance of the Extraction Stage on the Anti-Inflammatory Action of Fucoidans

The anti-inflammatory action of fucoidans is well known, based on both in vitro and some in vivo studies. The other biological properties of these compounds, their lack of toxicity, and the possibility of obtaining them from a widely distributed and renewable source, makes them attractive novel bioactives. However, fucoidans’ heterogeneity and variability in composition, structure, and properties depending on seaweed species, biotic and abiotic factors and processing conditions, especially during extraction and purification stages, make it difficult for standardization. A review of the available technologies, including those based on intensification strategies, and their influence on fucoidan composition, structure, and anti-inflammatory potential of crude extracts and fractions is presented.

Anti-Proliferative and Pro-Apoptotic vLMW Fucoidan Formulas Decrease PD-L1 Surface Expression in EBV Latency III and DLBCL Tumoral B-Cells by Decreasing Actin Network

Epstein-Barr virus (EBV) infects 95% of the world's population and persists latently in the body. It immortalizes B-cells and is associated with lymphomas. LCLs (lymphoblastoid cell lines, EBV latency III B-cells) inhibit anti-tumoral T-cell response following PD-L1 overexpression (programmed death-ligand 1 immune checkpoint). Many cancer cells, including some DLBCLs (diffuse large B-cell lymphomas), also overexpress PD-L1. Immunotherapies are based on inhibition of PD-L1/PD-1 interactions but present some dose-dependent toxicities. We aim to find new strategies to improve their efficiency by decreasing PD-L1 expression. Fucoidan, a polysaccharide extracted from brown seaweed, exhibits immunomodulatory and anti-tumor activities depending on its polymerization degree, but data are scarce on lymphoma cells or immune checkpoints. LCLs and DLBCLs cells were treated with native fucoidan (Fucus vesiculosus) or original very-low-molecular-weight fucoidan formulas (vLMW-F). We observed cell proliferation decrease and apoptosis induction increase with vLMW-F and no toxicity on normal B- and T-cells. We highlighted a decrease in transcriptional and PD-L1 surface expression, even more efficient for vLMW than native fucoidan. This can be explained by actin network alteration, suggesting lower fusion of secretory vesicles carrying PD-L1 with the plasma membrane. We propose vLMW-F as potential adjuvants to immunotherapy due to their anti-proliferative and proapoptotic effects and ability to decrease PD-L1 membrane expression.

Immunopotentiating Activity of Fucoidans and Relevance to Cancer Immunotherapy

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

Modulation of T Cell Responses by Fucoidan to Inhibit Osteogenesis

Fucoidan has sparked considerable interest in biomedical applications because of its inherent (bio)physicochemical characteristics, particularly immunomodulatory effects on macrophages, neutrophils, and natural killer cells. However, the effect of fucoidan on T cells and the following regulatory interaction on cellular function has not been reported. In this work, the effect of sterile fucoidan on the T-cell response and the subsequent modulation of osteogenesis is investigated. The physicochemical features of fucoidan treated by high-temperature autoclave sterilization are characterized by UV–visible spectroscopy, X-ray diffraction, Fourier transform infrared and nuclear magnetic resonance analysis. It is demonstrated that high-temperature autoclave treatment resulted in fucoidan depolymerization, with no change in its key bioactive groups. Further, sterile fucoidan promotes T cells proliferation and the proportion of differentiated T cells decreases with increasing concentration of fucoidan. In addition, the supernatant of T cells co-cultured with fucoidan greatly suppresses the osteogenic differentiation of MC3T3-E1 by downregulating the formation of alkaline phosphatase and calcium nodule compared with fucoidan. Therefore, our work offers new insight into the fucoidan-mediated T cell and osteoblast interplay.

Research Status and Hotspots of Anticancer Natural Products Based on the Patent Literature and Scientific Articles

Background: The patent literature contains a large amount of information on the internal state of current industrial technologies that are not available in other literature studies. Scientific articles are the direct achievements of theoretical research in this field and can reveal how current theories in basic research have developed. In this study, the progress and status of natural anticancer products in this field were summarized, and the research hotspots were explored through the analysis of the relevant patent literature and scientific articles. Methods: Patent data were retrieved from the incoPat patent retrieval database, and paper data were retrieved from the Web of Science core set and PubMed. GraphPad Prism 8, Microsoft Excel 2010, and CiteSpace 5.8.R3 were used to perform visual processing. The analyzed patent literature includes the patent applicant type, country (or region), and technical subject. The analyzed scientific article includes academic groups, subject areas, keyword clustering, and burst detection. Results: A total of 20,435 patent families and 38,746 articles were collected by 4 January 2022. At present, antitumor drugs derived from natural products mainly include 1) apoptosis inducers such as curcumin, gallic acid, resveratrol, Theranekron D6, and gaillardin; 2) topoisomerase inhibitors such as camptothecins, scaffold-hopped flavones, podophyllotoxin, oxocrebanine, and evodiamine derivatives; 3) telomerase inhibitors such as camptothecin and isoquinoline alkaloids of Chelidonium majus, amentoflavone, and emodin; 4) microtubule inhibitors such as kolaflavanone, tanshinone IIA analog, eugenol, and millepachine; 5) immunomodulators such as fucoidan, myricetin, bergapten, and atractylenolide I; 6) tumor microenvironment regulators such as beta-escin and icaritin; 7) multidrug resistance reversal agents such as berberine, quercetin, and dihydromyricetin; and 8) antiangiogenic and antimetastatic agents such as epigallocatechin-3-gallate, lupeol, ononin, and saikosaponin A. Conclusion: Anticancer natural product technology was introduced earlier, but the later development momentum was insufficient. In addition, scientific research activities are relatively closed, and technical exchanges need to be strengthened. Currently, the development of medicinal plants and the research on the anticancer mechanism of natural active products are still research hotspots, especially those related to immune checkpoints, essential oils, and metastatic cancer. Theories of traditional Chinese medicine (TCM), such as "restraining excessiveness to acquire harmony," "same treatment for different diseases," "Meridian induction theory," and "Fuzheng Quxie," have important guiding significance to the research of anticancer mechanisms and the development of new drugs and can provide new ideas for this process. Systematic Review Registration: [https://sourceforge.net/projects/citespace/], identifier [000755430500001].

l-fucose, a sugary regulator of antitumor immunity and immunotherapies

l-fucose is a dietary sugar that is used by cells in a process called fucosylation to posttranslationally modify and regulate protein behavior and function. As fucosylation plays essential cellular functions in normal organ and immune developmental and homeostasis, it is perhaps not surprising that it has been found to be perturbed in a number of pathophysiological contexts, including cancer. Increasing studies over the years have highlighted key roles that altered fucosylation can play in cancer cell-intrinsic as well as paracrine signaling and interactions. In particular, studies have demonstrated that fucosylation impact tumor:immunological interactions and significantly enhance or attenuate antitumor immunity. Importantly, fucosylation appears to be a posttranslational modification that can be therapeutically targeted, as manipulating the molecular underpinnings of fucosylation has been shown to be sufficient to impair or block tumor progression and to modulate antitumor immunity. Moreover, the fucosylation of anticancer agents, such as therapeutic antibodies, has been shown to critically impact their efficacy. In this review, we summarize the underappreciated roles that fucosylation plays in cancer and immune cells, as well as the fucosylation of therapeutic antibodies or the manipulation of fucosylation and their implications as new therapeutic modalities for cancer.

Fucoidan Independently Enhances Activity in Human Immune Cells and Has a Cytostatic Effect on Prostate Cancer Cells in the Presence of Nivolumab

Fucoidan compounds may increase immune activity and are known to have cancer inhibitory effects in vitro and in vivo. In this study, we aimed to investigate the effect of fucoidan compounds on ex vivo human peripheral blood mononuclear cells (PBMCs), and to determine their cancer cell killing activity both solely, and in combination with an immune-checkpoint inhibitor drug, Nivolumab. Proliferation of PBMCs and interferon gamma (IFNγ) release were assessed in the presence of fucoidan compounds extracted from Fucus vesiculosus, Undaria pinnatifida and Macrocystis pyrifera. Total cell numbers and cell killing activity were assessed using a hormone resistant prostate cancer cell line, PC3. All fucoidan compounds activated PBMCs, and increased the effects of Nivolumab. All fucoidan compounds had significant direct cytostatic effects on PC3 cells, reducing cancer cell numbers, and PBMCs exhibited cell killing activity as measured by apoptosis. However, there was no fucoidan mediated increase in the cell killing activity. In conclusion, fucoidan compounds promoted proliferation and activity of PBMCs and added to the effects of Nivolumab. Fucoidan compounds all had a direct cytostatic effect on PC3 cells, as shown through their proliferation reduction, while their killing was not increased.