Effects of lentinan on cytotoxic functions of human lymphocytes

Selective Biological Effects of Selenium-Enriched Polysaccharide (Se-Le-30) Isolated from Lentinula edodes Mycelium on Human Immune Cells

A common edible mushroom Lentinula edodes, is an important source of numerous biologically active substances, including polysaccharides, with immunomodulatory and antitumor properties. In the present work, the biological activity of the crude, homogenous (Se)-enriched fraction (named Se-Le-30), which has been isolated from L. edodes mycelium by a modified Chihara method towards human peripheral blood mononuclear cells (PBMCs) and peripheral granulocytes, was investigated. The Se-Le-30 fraction, an analog of lentinan, significantly inhibited the proliferation of human PBMCs stimulated with anti-CD3 antibodies or allostimulated, and down-regulated the production of tumor necrosis factor (TNF)-α by CD3+ T cells. Moreover, it was found that Se-Le-30 significantly reduced the cytotoxic activity of human natural killer (NK) cells. The results suggested the selective immunosuppressive activity of this fraction, which is non-typical for mushroom derived polysaccharides.

Molecular dynamics simulation of lentinan and its interaction with the innate receptor dectin-1

Lentinan, a β-1,3-D-glucan, is clinically used as an immune enhancement drug for tumor therapy. Dectin-1 is a cell-surface immune receptor, which plays an important role in immunological defense against fungal pathogens and β-glucan-mediated immune modulation. Herein we attempted to study the advanced structure of lentinan and how lentinan interacts with dectin-1 for its immune enhancement effect. We firstly used MD simulation and rigid macromolecule docking, combining some spectral techniques, to uncover the complex 3D conformation of a typical polysaccharide - lentinan, and the detailed interaction mode of lentinan with dectin-1. We proved by computational simulation that lentinan can maintain its triple-helix through hydrogen network and disclosed some structural properties of lentinan. We also characterized the affinity of lentinan to dectin-1 by LSPR and binding free energy calculation, and we found out that hydrogen bonds and CH-π interaction are the major contributors for lentinan's binding to dectin-1. Besides, after bound with lentinan, dectin-1 might surprisingly go through a conformational change. In summary, our work provided insights into lentinan's advanced structure and β-glucan recognition by dectin-1.

Intrathoracic infusion therapy with Lentinan and chemical irritants for malignant pleural effusion: a systematic review and meta-analysis of 65 randomized controlled trials

BACKGROUND

Aderivative of Shiitake mushrooms, Lentinan is used to control malignant pleural effusion (MPE) through intrathoracic infusion.

PURPOSE

To determine the clinical response, survival and safety of Lentinan plus chemical irritants, and the optimal combinations with chemical irritants, indication, threshold and optimal regimen for achieving the desired responses.

STUDY DESIGN

We performed a new systematic review and meta-analysis following the PRISMA guidelines.

METHODS

We collected all randomized controlled trials (RCTs) regarding Lentinan plus chemical irritants from Chinese and English electronic databases (from inception until March 2019). We evaluated their bias risk, synthesized data using meta-analysis, and summarized evidence quality following the Grades of Recommendation Assessment, Development and Evaluation approach.

RESULTS

We included 65 RCTs involving 4,080 patients and nine chemical irritants. Most trials had unclear bias risk. Lentinan with cisplatin significantly improved complete response [Risk ratio (RR) = 1.68, 95% confidence intervals (CI) (1.51 to 1.87), p < 0.00001, Fig.3a] and quality of life [RR = 1.51 95% CI (1.41 to 1.62), p < 0.00001, Fig.4], and decreased the risk of treatment failure, myelosuppression, gastrointestinal reaction, and chest pain. For patients with moderate to large volume of the pleural effusion, primary treatment, KPS score ≥ 50-60, or anticipated survival time ≥ 3months, Lentinan (3-4 mg/time, once a week for three to four times) withcisplatin (30-40 mg/m2 or 50-60 mg/m2) significantly improved complete response and decreased failure. Most results were robust and moderate quality.

CONCLUSION

The results suggest that Lentinan with chemical irritants, especially cisplatin is beneficial to the patient with MPE, and provide evidence for the indication, threshold, and optimal regimen that may achieve success and decrease failure.

Lentinan as an immunotherapeutic for treating lung cancer: a review of 12 years clinical studies in China

PURPOSE

Lentinan is a polysaccharide extracted from Shiitake mushrooms that have been used to improve general health for thousands of years in Asia. Lentinan injection is a clinically approved drug in several countries in Asia. The purpose of this study is to review the structure, preclinical and clinical studies, and molecular mechanisms of lentinan. Most importantly, the clinical effectiveness of lentinan as an adjuvant therapeutic drug in treating patients with lung cancer in China during the past 12 years is analyzed statistically.

METHODS

We carried out literature search of randomized controlled trials (RCTs) published from 2004 to 2016 based on CNKI (China National Knowledge Infrastructure), VIP (Chongqing VIP Chinese Scientific Journals Database) and Wanfang database, and 38 eligible RCTs of lentinan-associated lung cancer treatment were identified, containing 3,117 patients.

RESULTS

The structure and function relationship and underlying molecular mechanism of lentinan as an immunostimulant has been summarized. The mean value of overall response rate in treating lung cancer was increased from 43.3% of chemotherapy alone to 56.9% of lentinan plus chemotherapy [p < 0.001, 95% confidence interval (CI) 0.102-0.170]. Compared with chemotherapy alone, lentinan plus chemotherapy showed more efficacy in treating lung cancer (pooled RR 0.79, 95% CI 0.74-0.85) and no statistical heterogeneity was found among studies (I² = 11%).

CONCLUSION

Clinical data presented in the past 12 years shows that lentinan is effective not only in improving quality of life, but also in promoting the efficacy of chemotherapy during lung cancer treatment.

The use of lentinan for treating gastric cancer

Natural compounds containing fungal β-glucans have been used to improve general health for thousands of years in China and Japan. Lentinan, the backbone of β-(1, 3)-glucan with β-(1, 6) branches, is one of the active ingredients purified from Shiitake mushrooms and has been approved as a biological response modifier for the treatment of gastric cancer in Japan. Despite recent advances in chemotherapeutic agents, unresectable or recurrent gastric cancer remains an incurable disease, with survival rates being far from satisfactory. Recent clinical studies have shown that chemo-immunotherapy using lentinan prolongs the survival of patients with advanced gastric cancer, as compared to chemotherapy alone. In addition, trastuzumab, an antibody against HER2/neu growth factor receptor, has been used for the treatment of gastric cancer in combination with cytotoxic chemotherapeutic agents. Lentinan may exert a synergistic action with anti-cancer monoclonal antibodies to activate complement systems through the mechanism of antibody-dependent cellular cytotoxicity and complement dependent cytotoxicity. Because a better understanding of its biological activities should enable us to use lentinan more efficiently in the treatment of gastric cancer, immunological effects provided by β-glucans, a possible mode of action of lentinan, and its clinical application including future potential uses are discussed in the present review.

Polysaccharide from Lentinus edodes inhibits the immunosuppressive function of myeloid-derived suppressor cells

Reversing the function of immune suppressor cells may improve the efficacy of cancer therapy. Here, we have isolated a novel polysaccharide MPSSS (577.2 Kd) from Lentinus edodes and examined its effects on differentiation and function of myeloid-derived suppressor cells (MDSCs). MPSSS is composed of glucose (75.0%), galactose (11.7%), mannose (7.8%), and xylose (0.4%). In vivo, it inhibits the growth of McgR32 tumor cells, which is correlated with a reduced percentage of MDSCs in peripheral blood. In vitro, it induces both morphological and biophysical changes in MDSCs. Importantly, MPSSS up-regulates MHC II and F4/80 expression on MDSCs, and reverses their inhibition effect on CD4⁺ T cells in a dose-dependent manner. The mechanism study shows that MPSSS may stimulate MDSCs through a MyD88 dependent NF-κB signaling pathway. Together, we demonstrated for the first time that MPSSS stimulates the differentiation of MDSCs and reverses its immunosuppressive functions, shedding new light on developing novel anti-cancer strategies by targeting MDSCs.

β-Glucan from Lentinus edodes inhibits nitric oxide and tumor necrosis factor-α production and phosphorylation of mitogen-activated protein kinases in lipopolysaccharide-stimulated murine RAW 264.7 macrophages

Lentinan (LNT), a β-glucan from the fruiting bodies of Lentinus edodes, is well known to have immunomodulatory activity. NO and TNF-α are associated with many inflammatory diseases. In this study, we investigated the effects of LNT extracted by sonication (LNT-S) on the NO and TNF-α production in LPS-stimulated murine RAW 264.7 macrophages. The results suggested that treatment with LNT-S not only resulted in the striking inhibition of TNF-α and NO production in LPS-activated macrophage RAW 264.7 cells, but also the protein expression of inducible NOS (iNOS) and the gene expression of iNOS mRNA and TNF-α mRNA. It is surprising that LNT-S enhanced LPS-induced NF-κB p65 nuclear translocation and NF-κB luciferase activity, but severely inhibited the phosphorylation of JNK1/2 and ERK1/2. The neutralizing antibodies of anti-Dectin-1 and anti-TLR2 hardly affected the inhibition of NO production. All of these results suggested that the suppression of LPS-induced NO and TNF-α production was at least partially attributable to the inhibition of JNK1/2 and ERK1/2 activation. This work discovered a promising molecule to control the diseases associated with overproduction of NO and TNF-α.

Immunomodulatory beta-glucan from Lentinus edodes activates mitogen-activated protein kinases and nuclear factor-kappaB in murine RAW 264.7 macrophages

Lentinan, a cell wall β-glucan from the fruiting bodies of Lentinus edodes, is well known to be a biological defense modifier, but the signal transduction pathway(s) induced by Lentinan have not been elucidated. In this study, we extracted Lentinan (LNT-S) by ultrasonication from Lentinus edodes and report that, in murine RAW 264.7 macrophages, LNT-S glucan activated NF-κB p65 and triggered its nuclear translocation as determined by Western blotting. Moreover, LNT-S enhanced NF-κB-luciferase activity in the Dual-Luciferase gene system assay. Its upstream signaling molecules, MAPKs such as ERK1/2 and JNK1/2, were shown to be activated by assessing the level of phosphorylation in a time- and concentration-dependent manner, but its downstream proinflammatory enzyme, inducible NOS, was not observed. The data evaluated using a TNF-α ELISA kit and Griess reagent further demonstrated that no proinflammatory mediators such as TNF-α and NO were produced by LNT-S stimulation in RAW 264.7 cells. In contrast, LPS significantly induced inducible NOS expression and increased NO and TNF-α production, which are associated with activation of the NF-κB p65/p50 heterodimer complex. It is possible that LNT-S did not activate NF-κB p65/p50, and the activation of NF-κB p65 was not sufficient to stimulate cytokine production. These data demonstrate that LNT-S glucan carries out its immunomodulating activity by activating MAPK signaling pathways without secretion of TNF-α and NO.

Effect of ninjin-youei-to on Th1/Th2 type cytokine production in different mouse strains

Ninjin-youei-to (NYT; ren-shen-yang-rong-tang in Chinese) is a traditional herbal formula, which is widely used in Japan, Korea and China to modulate physiological immunity. The effects of oral administration of NYT on cytokine production from splenocytes were investigated in both C57BL/6 and BALB/c mice in which Th1 and Th2 were dominant, respectively. Splenocytes from C57BL/6 and BALB/c mice, which took NYT orally forfour weeks, were cultured with anti-mouse CD3 mAb, and the supernatant was examined for cytokine production using enzyme-linked immunosorbent assay (ELISA). Administration of NYT to C57BL/6 mice, increased the production of interleukin-4 (IL-4) significantly, and slightly decreased interferon-y (IFN-gamma) production from splenocytes. In contrast, the same treatment significantly increased IFN-gamma secretion from splenocytes of BALB/c mice. No remarkable changes of IL-12 production from splenocytes were observed in either strain of mice. These results suggest that oral administration of NYT ameliorates the excessive inclination of Th1 and Th2 type cytokine production, and NYT may provide a beneficial effects for the treatment of diseases caused by a skewed Th1-Th2 balance in the immune system.

Effects of lentinan on broiler splenocyte proliferation, interleukin-2 production, and signal transduction

Lentinan (LEN) is an intensively studied beta-glucan that has been shown to have immunostimulating and antitumor functions. However, it currently is not used in veterinary practice and animal production. This study was conducted to investigate the impacts of LEN on broiler splenocyte proliferation, interleukin-2 (IL-2) production, and to explore its effects on receptor signal transduction by determining signaling molecules, including nitric oxide (NO), cytosolic-free Ca2+, cytosolic cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP). The results showed that compared to the control all three measured doses, including 40, 80, and 160 microg/mL LEN, increased splenocyte proliferation and IL-2 production (P < 0.05). Lentinan increased splenocyte NO production and cytosolic-free calcium concentration in a dose-dependent manner (P < 0.001). After incubating splenocytes for 20 min, LEN increased intracellular cAMP and cGMP concentrations at a dose of 80 and 160 microg/mL, respectively. However, after incubating the splenocytes for 60 min, LEN had no effect on cytosolic cAMP and cGMP concentration irrespective of the LEN dosage. Those results indicated that LEN had immunostimulatory effects on splenocytes by increasing splenocyte proliferation and IL-2 production and by activating splenocyte receptor signal transduction.

Bioactive polysaccharides from traditional Chinese medicine herbs as anticancer adjuvants

PURPOSE OF STUDY

To review the nature, extent, bioactivities, and clinical application of polysaccharides in Traditional Chinese Medicine (TCM) especially as adjuvants in cancer treatment.

METHODOLOGY

Literature review.

FINDINGS

Many fungal- and plant-derived bioactive polysaccharides with a broad range of immunomodulatory activities are found in TCM. Some such polysaccharides have been developed into drugs and show clinical efficacy in controlled trials while the majority of such compounds remain as nutraceuticals with only preliminary research. Such polysaccharides are generally nontoxic and possess other bioactivities such as inducing differentiation, stimulating hematopoiesis, antimetastasis, and antiangiogenesis, which make them ideal adjuvants in modern cancer therapy.

CONCLUSION

Bioactive polysaccharides occur extensively in TCM herbs and are the basis of potentially useful application of TCM as an adjuvant in cancer therapies.

Enhancement of natural killer cell activity and T and B cell function by buffered vitamin C in patients exposed to toxic chemicals: the role of protein kinase-C

After exposure to many toxic chemicals, NK function can be decreased significantly. Weeks or months later, natural killer (NK) function can rebound to normal levels in some and can be suppressed for prolonged periods of time in other patients. In view of this, we decided to study the effect of buffered vitamin C on NK, T and B cell function in patients who had been exposed to toxic chemicals. After the first blood draw, 55 patients immediately ingested granulated buffered vitamin C in water at a dosage of 60 mg/Kg body weight. Exactly 24 hours later, blood was again drawn for a follow-up study of NK, T and B cell function. Vitamin C in high oral dose was capable of enhancing NK activity up to ten-fold in 78% of patients. Lymphocyte blastogenic responses to T and B cell mitogens were restored to the normal level after vitamin C usage. Signal transduction enzyme protein kinase C (PKC) appeared to be involved in the mechanism of induction of NK activity by vitamin C. We conclude that immune functional abnormalities can be restored after toxic chemical exposure by oral usage of vitamin C.

Strain differences in the cytotoxic activity and TNF production of murine macrophages stimulated by lentinan

The effect of lentinan, a glucan type immunomodulatory polysaccharide was studied on the antitumor cytotoxicity and on the TNF secretion of peritoneal macrophages in inbred H-2 congeneic mouse strains under in vivo and in vitro conditions. The cytotoxic activity and TNF secretion of murine macrophages was found to be elevated by lentinan in vitro and in vivo conditions. The effectiveness of lentinan to induce cytotoxicity and TNF secretion was highly influenced by the genotype of the host. The increased cytotoxicity of macrophages was modified by the H-2 and the background genes. The black background and the H-2a and H-2d haplotypes were associated with high responsiveness, while the albino and agouti background and the H-2b and the H-2k haplotypes with low responsiveness to lentinan treatment. The degree of TNF secretion of macrophages stimulated by lentinan was influenced by the H-2 genes only. Similarly, to the macrophage cytotoxicity the TNF secretion in the H-2a and H-2d haplotypes were found to be high, on the other hand, in the H-2b and H-2k were low.

Immunomodulatory and anti-tumour polysaccharides from medicinal plants

Many Chinese medicinal plants have immunomodulatory and anti-tumour activities. Most of the anti-tumour activities of these Chinese herbs are probably due to their immunostimulating polysaccharide components. A general scheme for the isolation and purification of the bioactive polysaccharides from naturally occurring medicinal plants is described. Hot-water extraction followed by various chromatographic methods are usually used to purify the bioactive polysaccharides. The different fractions separated from Chinese medicinal plants show a range of immunomodulatory and anti-tumour activities. The analytical methods used for monosaccharide sequence determination and structural elucidation of the bioactive polysaccharides are described, as are the tests used to evaluate their immunopharmacological activities, both in vitro and in vivo. The purification, characterization and structural elucidation of immunomodulatory polysaccharides from medicinal plants may have important implications in the immunotherapy of cancer and in the treatment of various other diseases.

Application of chemical immunomodulators to the treatment of cancer and AIDS

A number of potential advantages, development of promising new agents, and the discovery of synergy with cytokines or cell products continue to spur research into the application of chemical immunomodulators for the treatment of cancer and AIDS. In preclinical in vitro and in vivo systems, chemical immunomodulators definitely modulate the immune system and have therapeutic efficacy. Although clinical trials have shown the ability of these agents to modulate the human immune system, thus far chemical immunomodulators have generally not fulfilled the therapeutic promise generated in animal models for the treatment of human diseases. While the discrepancy in results between animal models and human trials is obvious, the basis is not apparent. Species differences in elimination kinetics, presentation of active drug at the site of action, and the development of tachyphylaxis have been postulated as reasons for the minimal activity of these agents in humans. In addition, the use of investigational techniques established for cytotoxic agents may not be appropriate for immunomodulators. As with any immunomodulator, determining an optimal immunostimulatory dose and schedule and applying the therapy to patients with minimal tumor burden would perhaps be more appropriate than use of a maximally tolerated dose in patients with advanced disease. A dose-immunological effect relationship has recently been demonstrated for levamisole at doses higher than those used for many years in levamisole trials (99). While research and clinical investigation have identified several potentially useful chemical immunomodulators, the elementary understanding of the biochemical mechanisms involved in immunoregulation remains basic. Future research must elucidate these mechanisms, particularly in humans, to maximize the benefits of chemical immunomodulators as single agents or combined with cytotoxic chemotherapeutic agents, surgery, radiation therapy, other immunomodulators, and antiviral agents.

Effect of lentinan on macrophage cytotoxicity against metastatic tumor cells

We studied the effect of lentinan, a fungal polysaccharide immunomodulator, on mouse peritoneal macrophages. The i.p. treatment of mice with 10 mg/kg lentinan affected the number, plastic-adherence, and endogen peroxidase activity of peritoneal cells. The cytotoxicity of lentinan-stimulated peritoneal macrophages was determined against several murine and human metastatic tumor targets: Lewis lung carcinoma (LLT) and two human melanomas, and was found to be significantly higher than that of the macrophages from control animals. However, the highly metastatic variant of LLT (LLT-HH) was resistant to the cytolytic effect of resident and lentinan-activated macrophages as well, indicating that the stimulation for cytotoxicity depends not only on the functional activity of the effector but also on the sensitivity of the target.

Effect of PSK and its subfractions on peripheral blood lymphocytes mediated cytotoxicity against urinary bladder tumor cells

Our previous studies have indicated that the protein-bound polysaccharide Kreha (PSK) enhances the cytotoxic activity of peripheral blood lymphocytes (PBL) against the T24 human urinary bladder tumor cell line in patients with bladder tumor. Since PSK consists of a mixture of various kinds of protein-bound polysaccharides, the present study was designed to examine which subfractions of PSK mediated the enhancement of cytotoxicity. When PSK was separated according to size, treatment of PBL with the 50 kilodalton (kd) or less fraction killed T24 cells more efficiently than unfractionated PSK-treated PBL. The higher molecular weight fractions did not enhance killing above the control level. PSK was fractionated on a diethylaminoethyl (DEAE)-cellulose column to obtain a protein rich fraction that absorbed onto the column and a polysaccharide rich fraction that did not. PBL treated with the polysaccharide rich fraction were able to kill T24 cells more effectively than unfractionated PSK-treated PBL. The protein rich fraction had no effect on the killing. Further fractionation of the polysaccharide rich fraction was performed by differential precipitation with ammonium sulfate. PBL treated with the precipitated fraction at 70-80% saturation (PSK Fraction D) enhanced cytotoxicity equal to that of the polysaccharide rich fraction. Treatment of PBL with the other fractions did not augment the cytotoxicity. These enhancement by PSK fractions were observed in healthy donors and also in patients with bladder tumor. An increase of the proliferative response of PBL to PSK Fraction D as well as unfractionated PSK was observed. Treatment of PBL with PSK Fraction D had no effect on the proportion of PBL binding to T24 cells, thus suggesting a post-binding effect. The structure of PSK Fraction D as inferred from the results of methylation analysis was mainly an alpha-glucan. These results demonstrate that PSK mediated enhancement of cytotoxicity and proliferation of PBL may be largely due to an alpha-glucan of less than 50 kd.

Enhanced induction of lymphokine-activated killer activity after lentinan administration in patients with gastric carcinoma

In 15 patients with gastric carcinoma, peripheral blood mononuclear cells (PBM) were obtained serially before and 3, 5 and 7 days after lentinan administration. The generation of lymphokine-activated killer (LAK) activity, induced by in vitro activation of PBM with interleukin 2 (IL 2), was significantly augmented 5 days after a single intravenous dose of 2 mg lentinan, when compared with that before lentinan injection. Natural killer (NK) activity of PBM was also significantly enhanced 7 days after the drug injection. However, the distribution of lymphocyte subsets exhibited no significant change following lentinan administration.

Extensive degradation of Aroclors and environmentally transformed polychlorinated biphenyls by Alcaligenes eutrophus H850

We have isolated and characterized a strain of Alcaligenes eurtrophus, designated H850, that rapidly degrades a broad and unusual spectrum of polychlorinated biphenyls (PCBs) including many tetra- and pentachlorobiphenyls and several hexachlorobiphenyls. This strain, which was isolated from PCB-containing dredge spoils by enrichment on biphenyl, grows well on biphenyl and 2-chlorobiphenyl but poorly on 3- and 4-chlorobiphenyl. Capillary gas-chromatographic analysis showed that biphenyl-grown resting cells of H850 degraded the components of 38 of the 41 largest peaks of Aroclor 1242 and 15 of the 44 largest peaks of Aroclor 1254, resulting in an overall reduction of PCBs by 81% for Aroclor 1242 (10 ppm) and 35% for Aroclor 1254 (10 ppm) in 2 days. Furthermore, H850 metabolized the predominantly ortho-substituted PCB congeners that resulted from the environmental transformation of the more highly chlorinated congeners of Aroclor 1242 by the upper Hudson River anaerobic meta-, para-dechlorination agent system C (J. F. Brown, R. E. Wagner, Jr., D. L. Bedard, M. J. Brennan, J. C. Carnahan, R. J. May, and J. J. Tofflemire, Northeast Environ. Sci. 3:167-179, 1984). The congener selectivity patterns indicate that a two-step process consisting of anaerobic dechlorination followed by oxidation by H850 can effectively degrade all of the congeners in Aroclor 1242 and possibly all those in Aroclor 1254.