Effective inhibition of a Strongylocentrotus nudus eggs polysaccharide against hepatocellular carcinoma is mediated via immunoregulation in vivo

Future prospect of polysaccharide as a potential therapy in hepatocellular carcinoma: A review

Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality worldwide. HCC almost exclusively develops in patients with chronic liver disease, driven by a vicious cycle of liver injury, inflammation and regeneration that typically spans decades. A variety of new agents are in development for the treatment of the disease. Polysaccharide is important component of higher plants, membrane of the animal cell and the cell wall of microbes. It is also closely related to the physiological functions. Recently, there has been growing interest in polysaccharides as bioactive natural products, particularly in treating HCC. This paper provides a review of recent experimental and clinical studies on the effects and potential applications of polysaccharides in HCC treatment, aiming to offer theoretical insights and inspiration for further research on the bioactivity mechanisms of polysaccharides in HCC treatment.

Antitumor immunostimulatory activity of the traditional Chinese medicine polysaccharide on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignancy, often associated with compromised immune function in affected patients. This can be attributed to the secretion of specific factors by liver cancer cells, which hinder the immune response and lead to a state of immune suppression. Polysaccharides derived from traditional Chinese medicine (TCM) are valuable constituents known for their immunomodulatory properties. This review aims to look into the immunomodulatory effects of TCM polysaccharides on HCC. The immunomodulatory effects of TCM polysaccharides are primarily manifested through the activation of effector T lymphocytes, dendritic cells, NK cells, and macrophages against hepatocellular carcinoma (HCC) both in vivo and in vitro settings. Furthermore, TCM polysaccharides have demonstrated remarkable adjuvant antitumor immunomodulatory effects on HCC in clinical settings. Therefore, the utilization of TCM polysaccharides holds promising potential for the development of novel therapeutic agents or adjuvants with advantageous immunomodulatory properties for HCC.

Thymus as Incontrovertible Target of Future Immune Modulatory Therapeutics

Thymus plays a crucial role in cellular immunity by acting as a warehouse for proliferating and differentiating lymphocytes. Thymic stromal cells educate T-cells to differentiate self from non-self antigens while nurse cells and thymoproteasome play a major role in the maturation and differentiation of T-cells. The thymic conditions dictate T-cells to cope with the risk of cancer development. A study was designed to demonstrate potential mechanisms behind the failure to eliminate tumors and impaired immune surveillance as well as the impact of delay in thymus regression on cancer and autoimmune disorders. Scientific literature from Pubmed; Scopus; WOS; JSTOR; National Library of Medicine Bethesda, Maryland; The New York Academy of Medicine; Library of Speech Rehabilitation, NY; St. Thomas' Hospital Library; The Wills Library of Guys Hospital; Repository of Kings College London; and Oxford Academic repository was explored for pathological, physiological, immunological and toxicological studies of thymus. Studies have shown that systemic chemotherapy may lead to micro inflammatory environment within thymus where conventionally and dynamically metastasized dormant cells seek refuge. The malfunctioning of the thymus and defective T and Treg cells, bypassing negative selection, contributes to autoimmune disorders, while AIRE and Fezf2 play significant roles in thymic epithelial cell solidity. Different vitamins, TCM, and live cell therapy are effective therapeutics. Vitamin A, C, D, and E, selenium and zinc, cinobufagin and dietary polysaccharides, and glandular extracts and live cell injections have strong potential to restore immune system function and thymus health. Moreover, the relationship between different ages/ stages of thymus and their corresponding T-cell mediated anti-tumor immune response needs further exploration.

Strongylocentrotus nudus egg polysaccharide (SEP) suppresses HBV replication via activation of TLR4-induced immune pathway

Chronic hepatitis B virus (HBV) infection is a worldwide public health problem that causes significant liver-related morbidity and mortality. In our previous study, Strongylocentrotus nudus eggs polysaccharide (SEP), extracted from sea urchins, had immunomodulatory and antitumor effects. Whether SEP has anti-HBV activity is still obscure. This study demonstrated that SEP decreased the secretion of hepatitis B surface antigen (HBsAg) and e antigen (HBeAg), as well as the replication and transcription of HBV both in vitro and in vivo. Immunofluorescence and immunohistochemistry results showed that the level of HBV core antigen (HBcAg) was clearly reduced by SEP treatment. Mechanistically, RT-qPCR, western blot, and confocal microscopy analysis showed that SEP significantly increased the expression of toll-like receptor 4 (TLR4) and co-localization with TLR4. The downstream molecules of TLR4, including NF-κb and IRF3, were activated and the expression of IFN-β, TNF-α, IL-6, OAS, and MxA were also increased, which could suppress HBV replication. Moreover, SEP inhibited other genotypes of HBV and hepatitis C virus (HCV) replication in vitro. In summary, SEP could be investigated as a potential anti-HBV drug capable of modulating the innate immune.

Polysaccharide from Strongylocentrotus nudus eggs regulates intestinal epithelial autophagy through CD36/PI3K-Akt pathway to ameliorate inflammatory bowel disease

Sea urchin is a popular food all over the world, of which eggs are main edible part. Previous studies suggested that polysaccharides from eggs of Strongylocentrotus nudus (SEP) exhibited immunomodulatory activities during anti-tumor therapy, nevertheless, effects of SEP on inflammatory bowel disease and its underlying mechanisms have never been reported. In the present study, we showed that the SEP inhibited dextran sodium sulfate-induced ulcerative colitis characterized by decreased disease activity index, restored colon length and body weight, improved histopathological changes, down-regulation of inflammatory cytokines levels and Th17/Treg ratios in C57BL/6 J mice. Moreover, immunofluorescence analysis suggested that SEP repaired gut barrier in UC mice, while 16S rDNA sequencing exhibited improved intestinal flora. Mechanistically, we found SEP significantly modulated autophagy-related factors in intestinal epithelial cells (IECs), while might contributed to pathogenesis of UC. Furthermore, we demonstrated PI3K/Akt pathway was involved in regulatory effect of SEP on lipopolysaccharide-induced autophagy of HT-29 cells. Besides, among possible polysaccharide binding receptors, change of the CD36 expression was most significant, which was associated with PI3K/Akt signals. Collectively, our study showed for the first time that the SEP might be used a prebiotic agent to improve IBD through regulating CD36-PI3K/Akt mediated autophagy of IECs.

Pharmacokinetic study of Strongylocentrotus nudus egg polysaccharide in rats and beagles using a 3H-labeling method

Strongylocentrotus nudus egg polysaccharide (SEP) extracted from sea urchins has potential anticancer activity. However, little is known about its pharmacokinetic properties. To investigate the pharmacokinetics of SEP, it was radiolabeled with tritium. Furthermore, a sensitive, selective, and rapid liquid scintillation counter (LSC) method for quantifying ³H-SEP in biological matrix was validated. The lower quantification limit of the method was 4 Bq. The relative standard deviations (RSDs) of the intra- and inter-day precision were <3.0% and <3.9%, respectively. ³H-SEP was successfully applied to investigate the pharmacokinetics of SEP after intravenous administration of 20, 40, and 80 mg/kg (40 μCi/kg) in rats and 5, 10, and 20 mg/kg (6 μCi/kg) in beagles. The AUC_(0-t) of SEP at three different doses was 487.81 ± 39.99 mg/L*h, 1,003.10 ± 95.94 mg/L*h, and 2,188.84 ± 137.73 mg/L*h in rats and 144.12 ± 3.78 mg/L*h, 322.62 ± 28.03 mg/L*h, and 754.17 ± 37.79 mg/L*h in beagles. The terminal elimination half-life (t_1/2) of SEP was longer in beagles (204.29 ± 139.34 h) than in rats (35.48 ± 6.04 h). The concentration of SEP in plasma declined rapidly in both rats and beagles. All the study results provide detailed pharmacokinetic profiles of SEP in two kinds of animals, which will be helpful for further development.

Strongylocentrotus nudos Egg Polysaccharide induces autophagy and apoptosis in leukaemia cells by regulating mitochondrial function

In this study, we investigated the ability of the Polysaccharide from the Eggs of Strongylocentrotus nudus (SEP) to regulate cellular autophagy and apoptosis in leukaemia cells. Human acute myeloid leukaemia (AML) cells (HL60) and murine AML cells (L1210) treated with SEP were used to assess viability using Cell Counting Kit‐8, cytotoxicity by measuring lactate dehydrogenase release, the generation of reactive oxygen species (ROS) by DCFH‐DA staining. In addition, we utilized a mouse model of leukaemia in which L1210 cells were injected into DBA/2 mice by sub‐axillary injection. Treatment with SEP decreased cell viability, increased in cytotoxicity and increased the release of ROS in a dose‐dependent manner. SEP treatment was also associated with the activation of pro‐apoptotic proteins cleaved caspase‐3, cleaved caspase‐9 and cleaved poly (ADP‐ribose) polymerase (PARP). Activation of the apoptotic pathway led to the release of cytochrome C (CytoC) into the cytosol of the cell resulting in decreased membrane potential. The effect of SEP treatment was depended on the activation of the nuclear factor kappa‐B (NF‐κB) signalling pathway as SEP treatment led to an increase in NF‐κB phosphorylation, and inhibition of NF‐κB signalling using PDTC blocked SEP‐mediated activation of apoptosis. Treatment with SEP also prolonged survival time in our leukaemia mouse model and was associated with diminished tumour volume, increased leucocyte and lymphocyte proliferation, promoted pro‐inflammatory factor release in serum and enhanced immune function. Taken together, these data suggest that SEP inhibits the progression of leukaemia by initiating mitochondrial dysfunction, autophagy, and apoptosis via the NF‐κB signalling pathway.

Using Traditional Chinese Medicine to Treat Hepatocellular Carcinoma by Targeting Tumor Immunity

As the leading cause of cancer-related death, hepatocellular carcinoma (HCC) threatens human health and limited treatments are available to cure the disease efficiently and effectively. The particularly immunotolerant environment of the liver lowers the efficacy of current therapies in patients with advanced HCC. Traditional Chinese medicine (TCM) is gathering increasing interest due to the immunoregulatory properties of certain compounds. In advanced HCC, TCM can restore immunosurveillance to promote antitumor effects in several ways, including the upregulation of immunostimulatory factors and the downregulation of immunosuppressive factors. The characteristic multitarget regulation of TCM compounds may provide new insights regarding effective HCC immunotherapies. Here, we review the immunoregulatory potency of TCMs for treating HCC and explain how individual TCM drugs and complex formulas remodel the immune environment in various cell- and cytokine-dependent manners.

Polysaccharide enhanced NK cell cytotoxicity against pancreatic cancer via TLR4/MAPKs/NF-κB pathway in vitro/vivo

A polysaccharide isolated from Strongylocentrotus nudus eggs (SEP) reportedly displays immune activity in vivo. Here, its effect and underlying mechanism in the treatment of pancreatic cancer were investigated. SEP obviously inhibited pancreatic cancer growth by activating NK cells in vitro/vivo via TLR4/MAPKs/NF-κB signaling pathway, The tumor inhibitory rate achieved to 44.5% and 50.8% at a dose of 40 mg/kg in Bxpc-3 and SW1990 nude mice, respectively. Moreover, SEP obviously augmented the Gemcitabine (GEM) antitumor effect by upregulating NKG2D, which improved the sensitivity of NK cells targeting to its ligand MICA; meanwhile, the antitumor inhibitory rate was 68.6% in BxPC-3 tumor-bearing mice. Moreover, SEP reversed GEM-induced apoptosis and atrophy in both spleen and bone marrow via suppressing ROS secretion in vivo. These results suggested that pancreatic cancer was effectively inhibited by SEP-enhanced NK cytotoxicity mediated primarily through TLR4/MAPKs/NF-κB signaling pathway, representing a potential immunotherapy candidate for the treatment of pancreatic cancer.

Combined α-programmed death-1 monoclonal antibody blockade and fractionated radiation therapy reduces tumor growth in mouse EL4 lymphoma

The programmed death (PD) pathway is frequently present in the tumor microenvironment (TME) and suppresses tumor immunity by inhibiting the activity of tumor-infiltrating lymphocytes (TILs), particularly, CD8⁺ lymphocytes. PD immunotherapy involves stimulation of the immune response in the region surrounding the tumor but is insufficient to prevent tumor progression. Therefore, in this study, we examined the effects of combined PD immunotherapy with fractionated radiotherapy (RT) on antitumor immunity and tumor growth in lymphoma.

The immune cell profiles of the TME, blood, and secondary lymphoid organs were determined 7 days after treatment. Four combination therapies were compared. The synergistic effects of αPD-1 mAb and fractionated RT on increased CD8⁺ lymphocytes in the TME, blood, and secondary lymphoid organs led to substantial tumor regression in mouse EL4 lymphoma, both locally and systemically. Fractionated RT for 4 days followed by αPD-1 mAb therapy was significantly superior to other schemes in terms of overall survival rates and curative rates in xenograft model mice. Our data indicated that substantial immune responses occurred following combination therapy with fractionated RT and αPD-1 mAb immunotherapy. Our findings provide important insights into the use of RT plus αPD-1 mAb as an efficacious combinatorial therapy.

Methods of extraction, separation, purification, structural characterization for polysaccharides from aquatic animals and their major pharmacological activities

The further development of fishery resources is a hotspot in the development of the fishery industry. However, how to develop aquatic animal resources deeply is a key point to be solved in the fishery industry. Over the past decades, numerous aquatic animals have gained great attention in the development and utilization of their bioactive molecules which are of therapeutic applications as nutraceuticals and pharmaceuticals. Recent research revealed that aquatic animals are composed of many vital moieties, such as polysaccharides and proteins, which provide health benefits beyond basic nutrition. In particular, aquatic animal polysaccharides are gaining worldwide popularity owing to their high content, ease of extraction, specific structure, few side effects, prominent therapeutic potential and incorporation in functional foods and dietary supplements. Thus, tremendous research on the isolation, identification and bioactivities of polysaccharides has been carried out. This review presents comprehensive viewpoints on extraction, separation, purification, structural characterization and bioactivity of various polysaccharides from aquatic animals, such as sea cucumber, abalone, oyster and mussels. In addition, this review profiled a brief knowledge on both current challenges and future scope in aquatic animal polysaccharides field. The review will be a direction of deep processing in fishery resources, which is a hotspot, but technical bottleneck. Furthermore, the review could be served as a useful reference material for further investigation, production and application of polysaccharides from aquatic animals in functional foods and therapeutic agents.

A novel mechanism of tumor-induced thymic atrophy in mice bearing H22 hepatocellular carcinoma

Background

Thymic atrophy was discovered in tumor-bearing mice in recent years.

Methods

Flow cytometry was carried out including Annexin V-FITC/PI double staining, PI staining, Terminal dUTP nick-end labeling, CD3-FITC/CD19-PE and CD8-FITC/CD4-PE double staining. Enzyme-linked immunosorbent assay and polymerase chain reaction were also investigated.

Results

According to our experiments, we demonstrated that no signs of apoptosis in thymocytes were found in H22-bearing mice, while the proportions of CD4⁺ T cells and CD8⁺ T cells in thymuses were remarkably increased, the opposite tendency was found in peripheral bloods, and only CD3⁺CD8⁺ T cells were discovered in H22 solid tumors. We further discovered that the level of thymosin alpha 1 (Tα1) and the expression of Wnt4 in thymus of H22-bearing mice were significantly improved than control, which indicated the active proliferation and differentiation of thymocytes. Our study revealed that CD8⁺ T cells could not effectively eliminate H22 cells independently when CD4⁺ T cells were suppressed by tumors, while the body would only enhance the differentiation and maturation of T cells in thymuses and release them to solid tumor to reinforce antitumor immunocompetence, leading to a vicious cycle which finally led to thymic atrophy.

Conclusion

Our data propose a novel mechanism of tumor-induced thymic atrophy regulated by abnormal immunoreaction and may provide new ideas for the immunotherapy of tumors.

SEP enhanced the antitumor activity of 5-fluorouracil by up-regulating NKG2D/MICA and reversed immune suppression via inhibiting ROS and caspase-3 in mice

Chemotherapy and immunotherapy are the main remedies used in cancer treatment. Because immunotherapy can not only reduce the toxicity of chemotherapeutics but also enhance antitumor effects in vivo, combining these two therapies is a trend that continues to gain more attention in clinic. SEP, a polysaccharide isolated from Strongylocentrotus nudus egg, has been reported to display antitumor activity by stimulating immune cells, including NK and T cells, via TLR2 and TLR4. In the present study, the synergistic effect between SEP and 5-fluorouracil (5-FU), a traditional cytotoxic drug, in vitro and in vivo was investigated. The results obtained indicated that SEP alone stimulated NK-92 cytotoxicity and coordinated with 5-FU to augment the cytotoxicity of NK-92 cells against HepG-2 or A549 cells in vitro. SEP promoted NK-92 activity by stimulating NKG2D and its downstream DAP10/PI3K/Erk signaling pathway. Additionally, 5-FU could increase MICA expression on HepG-2 or A549 cells and prevent membrane MICA from shedding as soluble MICA, which were abrogated in the tumor cells transfected with ADAM 10 overexpression plasmid. Moreover, in H22- or Lewis lung cancer (LLC)-bearing mouse models, SEP reversed 5-FU-induced atrophy and apoptosis in both the spleen and bone marrow in vivo by suppressing ROS generation and caspase-3 activation. All of these results highlight the potential for the combination of SEP and 5-FU in cancer therapy in the future.

Combined SEP and anti-PD-L1 antibody produces a synergistic antitumor effect in B16-F10 melanoma-bearing mice

The increased PD-L1 induces poorer prognosis in melanoma. The treatment with PD-1/PD-L1 antibodies have a low response rate. The combination immunotherapies are the encouraging drug development strategy to receive maximal therapeutic benefit. In this study, we investigated the enhanced antitumor and immunomodulatory activity of combined SEP and αPD-L1 in B16-F10 melanoma-bearing mice. The results shown that combined SEP and αPD-L1 presented significant synergistic antitumor effects, increased the frequency of CD8⁺ and CD4⁺ T cells in spleen and tumor, cytotoxic activity of CTL in spleen, and IL-2 and IFN-γ levels in splenocytes and tumor. The combination treatment also produced synergistic increase in P-ERK1/2 level in spleen. Immunohistochemistry shown that SEP induced the PD-L1 expression in melanoma tissue possibly by promoting IFN-γ excretion, which led to the synergistic anti-tumor effects of aPD-L1 and SEP. Furthermore, in the purified T lymphocyte from the naive mice, the combination of SEP and αPD-L1 had more potent than SEP or αPD-L1 in promoting T lymphocyte proliferation and cytokines secretion including IL-2 and IFN-γ, at least partially by activating MEK/ERK pathway. Our study provides the scientific basis for a clinical trial that would involve combination of anti-PD-L1 mAb and SEP for sustained melanoma control.

In silicoassessment and structural characterization of antioxidant peptides from major yolk protein of sea urchinStrongylocentrotus nudus

Sea urchin gonads have been demonstrated to contain major yolk protein (MYP), which can be hydrolyzed by enzymes to release biologically active peptides.

Characterization and protective effect of Polygonatum sibiricum polysaccharide against cyclophosphamide-induced immunosuppression in Balb/c mice

In this study, the polysaccharide from Polygonatum sibiricum (PSP) was evaluated for the immunomodulatory activity by the cyclophosphamide (Cy)-induced immunosuppressed-model in vivo. The PSP has been analyzed in order to identify a variety of chemical properties such as monosaccharide compositions and structural confirmation. The results show that the main components of PSP were galactose and rhamnose. The PSP could significantly stimulate neutral red phagocytosis of RAW264.7 macrophages. Compared with the cyclophosphamide group, PSP accelerated recovery of spleen and thymus indexes, and enhanced T cell and B cell proliferation responses as well as peritoneal macrophage phagocytosis. In addition, PSP treatment restored the levels of IL-2, TNF-α, IL-8 and IL-10 in the serum of the Cy-treated mice in a dose-dependent manner. Therefore, PSP played an important role in the protection against immunosuppression in the Cy-treated mice and could be used as a potential immunostimulant agent.

Enhanced antitumor activity of gemcitabine by polysaccharide-induced NK cell activation and immune cytotoxicity reduction in vitro/vivo

The polysaccharide SEP has been reported to activate NK and T cells via TLR2/4. Here, the combination of gemcitabine (GEM) and SEP against HepG-2 was investigated. SEP apparently enhanced antitumor activity of gemcitabine against liver cancer through stimulating NKG2D and DAP10/Akt pathway to activate NK cells. The NKG2D upregulation could improve the sensitivity of NK-92 cells targeting to its ligand MICA expressed on HepG-2 cells. Meanwhile, GEM up-regulated MICA expression and attenuated soluble MICA secretion through inhibiting ADAM10 expression, which in turn enhanced the cytotoxicity of NK-92 cells against cancer cells. SEP remarkably enhanced GEM antitumor activity with an inhibitory rate of 79.1% in an H22-bearing mouse model. Moreover, SEP reversed atrophy and apoptosis caused by GEM in both spleen and bone marrow through suppressing ROS secretion in vivo. The data indicated that the combination of SEP and GEM is a potential chemo-immunotherapy strategy for liver cancer treatment clinically.

A polysaccharide component from Strongylocentrotus nudus eggs inhibited hepatocellular carcinoma in mice by activating T lymphocytes

A component purified from Strongylocentrotus nudus eggs on a diethylaminoethyl cellulose-52 chromatography column and eluted using a NaCl solution gradient (SEP-S), is a homogeneous polysaccharide of α-D-glucan with a reduced molecular weight of 9.33×10⁵ Da, compared with that of S. nudus egg polysaccharide (SEP). In an in vivo antitumor assay of histocompatibility-22 hepatocellular carcinoma in tumor-bearing mice, the inhibitory rates at SEP-S doses of 5, 10 and 20 mg/kg/day were 38.8, 50.7 and 70.3%, respectively. In addition, the spleen and thymus indices and the percentages of cluster of differentiation (CD) 4⁺ and CD8⁺ T cells were significantly increased, and the activity of cytotoxic T lymphocytes was notably enhanced, suggesting that the anti-hepatocellular carcinoma activity is mediated by boosting the immune system. In vitro experiments also demonstrated that splenocyte proliferation induced by SEP-S was inhibited by the toll-like receptor (TLR) 2 and TLR4 monoclonal antibodies. These data indicate that SEP-S is a polysaccharide component possessing high anti-hepatocellular carcinoma activity and may be a potential immunotherapy candidate for the treatment of liver cancer.

Targeting of growth factors in the treatment of hepatocellular carcinoma: The potentials of polysaccharides

Hepatocellular carcinoma (HCC) has become a leading cause of cancer-associated mortality worldwide and is thus of great concern. Although various chemotherapeutic drugs are currently used for the treatment of HCC, severe side effects associated with these treatments have prompted interest in novel therapies, including the use of certain biological macromolecules such as polysaccharides. Several studies have shown that polysaccharides have anticancer and antiproliferative effects on HCC. Vascular endothelial growth factor, transforming growth factor β, epidermal growth factor and fibroblast growth factor may be effective targets for polysaccharides and may modulate tumor growth and immunity through increasing the expression levels of cytokines. The present review focuses on the ways in which growth factors contribute to the development of HCC, and on the anti-growth factor activities of natural and synthetic polysaccharides, as well as their effect on proinflammatory cytokines.

Bovine lactoferricin P13 triggers ROS-mediated caspase-dependent apoptosis in SMMC7721 cells

Bovine lactoferricin P13 (LfcinB-P13) is a peptide derived from LfcinB. In the present study, the effect of LfcinB-P13 on the human liver cancer cell line SMMC7721 was investigated in vitro and in vivo. The results of the present study indicate that LfcinB-P13 significantly decreased SMMC7721 cell viability in vitro (P=0.032 vs. untreated cells), while exhibiting low cytotoxicity in the wild-type liver cell line L02. In addition, the rate of apoptosis in SMMC7721 cells was significantly increased following treatment with 40 and 60 µg/ml LfcinB-P13 (P=0.0053 vs. the control group), which was associated with an increase in the level of reactive oxygen species (ROS) and the activation of caspase-3 and -9. Furthermore, ROS chelation led to the suppression of LfcinB-P13-mediated caspase-3 and -9 activation in SMMC7721 cells. LfcinB-P13 was demonstrated to markedly inhibit tumor growth in an SMMC7721-xenograft nude mouse model. The results of the present study indicate that LfcinB-P13 is a novel candidate therapeutic agent for the treatment of liver cancer.

Cecropin-P17, an analog of Cecropin B, inhibits human hepatocellular carcinoma cell HepG-2 proliferation via regulation of ROS, Caspase, Bax, and Bcl-2

Cecropin-P17 is a peptide derived from Cecropin B. In this study, we investigated the effects and relative mechanisms of Cecropin-P17 in a human liver cancer cell line (HepG-2) in vitro and in vivo. A cell viability assay, Annexin V/propidium iodide assay, western blot, flow cytometry, quantitative real-time polymerase chain reaction, and a tumor-xenograft model were applied to elucidate the mechanism exerted by Cecropin-P17 on HepG-2 cells. Cecropin-P17 significantly inhibited the proliferation of HepG-2 cells and demonstrated low cytotoxicity to normal liver cells in vitro. The apoptotic rate of HepG-2 cells was increased after Cecropin-P17 treatment together with increased production of reactive oxygen species. Moreover, Cecropin-P17 stimulated caspase-3, caspase-9, and Bax and inhibited Bcl-2 on both the transcriptional and translational levels. Finally, Cecropin-P17 significantly suppressed tumor growth in a HepG-2-bearing nude mouse model. All of these results indicated that Cecropin-P17 could be a potential agent for the treatment of liver cancer.

Impact of melatonin receptor deletion on intracellular signaling in spleen cells of mice after polymicrobial sepsis

OBJECTIVE

Melatonin is known to influence immune functions and to ameliorate outcome after septic challenge but it is unknown whether this is mediated by melatonin receptor activation. This study aimed to elucidate molecular differences in spleen and ex vivo splenocytes of wild-type (WT) and melatonin receptor double knockout mice (KO) after polymicrobial sepsis.

SUBJECTS AND METHODS

C3H/HeN wild-type and MT1-/-/MT2-/- mice underwent sham operation or cecum ligation and incision (CLI) and remained anesthetized for 1 h. Splenocytes were isolated and treated in culture with physiological melatonin concentrations (1 nM).

RESULTS

Plasma TNFα levels were consistently high after 1 h of CLI. Basal circulating leukocyte numbers were slightly higher in KO animals. We detected transcriptional differences in splenocytes of the knockout strain concerning proinflammatory mediators. Expression levels of IL-1β, IL-2, CXCR2, L-Selectin, TNFα, CXCL2 and ICAM-1 were strongly increased in splenocytes of KO mice. Splenocytes of KO mice displayed reduced ERK and p38 as well as increased JNK phosphorylation. None of the analyzed factors were influenced by melatonin in the culture medium.

CONCLUSIONS

The results of this study indicate an increased proinflammatory status of mice deficient in both membrane-bound melatonin receptors reflected by altered activation of MAPK cascades and transcriptional activation of proinflammatory mediators.

The anti-lung cancer activity of SEP is mediated by the activation and cytotoxicity of NK cells via TLR2/4 in vivo

Strongylocentrotus nudus egg polysaccharide (SEP) has been reported to display antitumor activity. However, the effects of SEP and its underlying mechanism in the treatment of lung cancer remain unclear, particularly with an immunodeficient mouse model of human non-small cell lung cancer (NSCLC). In the present study, we investigated the anti-lung cancer effects of SEP and its underlying mechanism of action in both Lewis lung cancer (LLC)-bearing C57/BL6J mice and human NSCLC H460-bearing nude mice. Although SEP showed no inhibitory effects on tumor cells in vitro, it markedly stimulated the percentage of CD3-NK1.1(+) cells and natural killer (NK) cell cytotoxicity in the spleens of nude mice and C57/BL6J mice. In LLC-bearing mice, SEP not only inhibited tumor growth but also promoted NK-mediated cytotoxicity, the NK1.1(+) cell population, and IL-2 and IFN-γ secretion. SEP significantly suppressed H460 growth in nude mice, which was abrogated by the selective depletion of NK cells via the intraperitoneal injection of anti-asialo GM-1 antibodies. Furthermore, anti-TLR2/4 antibodies blocked both SEP and NK cell binding and SEP-induced perforin secretion. SEP-induced proliferation and IFN-γ secretion by NK cells in wild type mice were partially impaired in TLR2 or TLR4 knockout mice. These results suggest that SEP-promoted NK cytotoxicity, which was partially mediated via TLR2 and TLR4, was the main contributing factor to lung cancer inhibition in vivo and that SEP may be a potential immunotherapy candidate for the treatment of lung cancer.

Anticancer and cancer preventive properties of marine polysaccharides: some results and prospects

Many marine-derived polysaccharides and their analogues have been reported as showing anticancer and cancer preventive properties. These compounds demonstrate interesting activities and special modes of action, differing from each other in both structure and toxicity profile. Herein, literature data concerning anticancer and cancer preventive marine polysaccharides are reviewed. The structural diversity, the biological activities, and the molecular mechanisms of their action are discussed.

BF-30 effectively inhibits ciprofloxacin-resistant bacteria in vitro and in a rat model of vaginosis

Bacterial infections are becoming increasingly difficult to treat due to the increasing number of multidrug-resistant strains. Cathelicidin-BF (BF-30) is a cathelicidin-like antimicrobial peptide and exhibits broad antimicrobial activity against bacteria. In the present study, the antibacterial activity of BF-30 against ciprofloxacin-resistant Escherichia coli and Staphylococcus aureus was examined, and the protective effects of this peptide against these bacteria in rats with bacterial vaginosis were identified for the first time. The data showed that BF-30 had effective antimicrobial activities against ciprofloxacin-resistant E. coli and S. aureus. The minimal inhibitory concentrations for both bacterial strains were 16 μg/ml, and the minimal bactericidal concentrations were 64 and 128 μg/ml, respectively. A time course experiment showed that the CFU counts rapidly decreased after BF-30 treatment, and the bacteria were nearly eliminated within 4 h. BF-30 could reduce the fold change (CFU/ml) in local colonization by drug-resistant E. coli and S. aureus to 0.01 at a dose of 0.8 mg/kg/day in the rats' vaginal secretions. In addition, BF-30 induced membrane permeabilization and bound to the genomic DNA, interrupting protein synthesis. Taken together, our data demonstrate that BF-30 has potential therapeutic value for the prevention and treatment of bacterial vaginosis.

Anticancer polysaccharides from natural resources: a review of recent research

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

Nutraceutical functionalities of polysaccharides from marine invertebrates

Many researchers are seeking functional materials from marine resources. These marine resources can be used as traditional food additives, and specifically, these are based on polysaccharides. To date, there is a big opportunity to develop new high-value added products with indispensable functional characteristics, which can be used in nutraceuticals either as additives or supplements. Also, a crossover in the pharmaceutical market may be established. Some glycosaminoglycans (GAGs) mimetic-type molecules are already being utilized in the field of nutrition as well as in the cosmetics industry. This chemical is used as a dietary supplement to maintain the structure and function of cartilages, for the relief of pain caused by osteoarthritic joints, and can also be used as an anti-inflammatory agent. Recently, in relation to the prevalence of mad cow disease and avian influenza, the production of GAGs from marine invertebrates offers new market opportunities as compared with that obtained from bovine or avian livestock.