Synergistic induction of lymphokine (IL-2)-activated killer activity by IL-2 and the polysaccharide lentinan, and therapy of spontaneous pulmonary metastases

A new application of Trichoderma asperellum as an anopheline larvicide for eco friendly management in medical science

Microfungal applications are increasing daily in the medical science. Several species of Trichoderma are widely used in agricultural fields as biological control and plant growth promoting agents. The application of Trichoderma asperellum as an entomopathogenic fungus against the Anopheles mosquito, a vector of malaria, is a novel control approach. Controlling malaria with eco-friendly management practices is an urgent need. We isolated three T. asperellum from different natural sources using serial dilution and mosquito baiting techniques. The fungi were identified on the basis of phenotypical and molecular characteristics. The fungi were grown in different natural media to examine spore production ability and the fungal spore suspensions were applied to the anopheline larvae to determine their larvicidal activity in vitro. We investigated the efficacy of crude ME (methanolic extract) and different methanolic fractions (MFs) of the fungal extracts against anopheline larvae. Methanolic Fraction 8 (MF8) exhibited the strongest larvicidal activity. A GC-MS analysis of MF8 and a Chemolibrary search were performed to identify the active agents in the fungal extracts. Among the three isolates of T. asperellum, the TaspSKGN2 isolate showed the lowest LD50 (2.68 × 107 conidia/mL) and LT50 values (12.33 h). The crude ME exhibited LD50 values of 0.073 mg/mL and LT50 values of 11.33 h. MF8 showed LD50 values of 0.059 mg/mL and LT50 values of 8.57 h. In GC-MS study of MF8, 49 compounds were found. Among these, seven compounds (2,3-di hydro thiopene, p-cymene, alpha-pinene, hexadecanoic acid, 8-methyl quinoline, (Z,Z)-9,12-octa decadienoic acid, methyl ester, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-Pyran-4-one-) with high abundance were found to have insecticidal efficacy by a literature survey. We detected a reduction in the phenoloxidase content inside the cuticle and hemolymph of the anopheline larvae after a few hours of interaction with ME (0.073 mg/mL). Thus Trichoderma asperellum has new applications for the control of Anopheles spp. malaria vectors.

In vitro cytostatic and immunomodulatory properties of the medicinal mushroom Lentinula edodes

Lentinula edodes, known as "shiitake" is one of the widely used medicinal mushrooms in the Orient. Antitumour activity of extracts of this mushroom has been widely demonstrated in animals and humans. However, this activity was shown to be host mediated and not by direct cytotoxic activity to cancer cells. This study demonstrates cytotoxic and cell growth inhibitory (cytostatic) effect of aqueous extracts of the mushroom on MCF-7 human breast adenocarcinoma cell line using an MTT cytotoxicity assay. Such effect was demonstrated with fruit body and mycelial extracts, the difference being that there was no significant suppression on normal cells with the latter. Furthermore mycelial extracts did not induce any cytostatic effect in both cancer and normal cell lines based on a DNA synthesis assay. The significant suppression of the proliferation of cancer cells was reflected by the comparatively low IC(50) values and the simultaneous higher respective values on normal fibroblast cells. The immunostimulatory activity of both fruit body and mycelial extracts was tested by the lymphocyte transformation test (LTT), which is based on the capacity of active immunomodulators to augment the proliferative response of rat thymocytes to T mitogens in vitro. Both fruit body and mycelial preparations were able to enhance the proliferation of rat thymocytes directly and act as co-stimulators in the presence of the T-mitogen PHA. Interestingly both extracts, similarly to zymosan showed SI(comit)/SI(mit) ratios of about 2, indicating adjuvant properties. Overall L. edodes aqueous extracts have demonstrated direct inhibition of the proliferation of human breast cancer cells in vitro and immunostimulatory properties in terms of mitogenic and co-mitogenic activity in vitro.

Dendritic cells might be one of key factors for eliciting antitumor effect by chemoimmunotherapy in vivo

In this study, we demonstrated that chemoimmunotherapy using S-1, a novel oral fluoropyrimidine anticancer drug, combined with lentinan (LNT), a beta (1 --> 3) glucan, was effective in vivo, and we clarified the augmentation of the function of dendritic cells (DCs) in vivo and in vitro. The survival period of Colon-26-bearing mice treated with S-1 + LNT was significantly more prolonged than that of mice treated with S-1 alone (P < 0.05). On the other hand, LNT did not prolong the survival period when combined with S-1 in Colon-26-bearing athymic mice. The frequency of CD86+ DCs infiltrated into Colon-26 was increased in mice treated with S-1 + LNT, and splenic DCs harvested from mice treated with S-1 + LNT showed more potent T-cell proliferation activity than that of DCs from mice treated with S-1 alone (P < 0.05). Furthermore, the activity of cytotoxic T lymphocytes (CTLs) in splenocytes of S-1 + LNT-treated mice was specific and more potent than that of CTLs from mice treated with S-1 alone (P < 0.05). These results suggest that modulation of specific immunity with LNT has a significant role in enhanced antitumor effects through the modification of DC function. We demonstrated that DCs might play an important role in chemotherapy, and the combination therapy of S-1 and LNT presents a promising chemoimmunotherapy, which might lead to better survival for cancer patients.

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.

Pilot study of a specific dietary supplement in tumor-bearing mice and in stage IIIB and IV non-small cell lung cancer patients

Previously, a specific dietary supplement, selected vegetables (SV), was found to be associated with prolonged survival of stage III and IV non-small cell lung cancer (NSCLC) patients. In this study, several anticancer components in SV were measured; the anticancer activity of SV was assessed using a lung tumor model, line 1 in BALB/c mice. SV was also used in conjunction with conventional therapies by stage IIIB and IV NSCLC patients whose survival and clinical responses were evaluated. A daily portion (283 g) of SV was found to contain 63 mg of inositol hexaphosphate, 4.4 mg of daidzein, 2.6 mg of genistein, and 16 mg of coumestrol. Mouse food containing 5% SV (wt/wt) was associated with a 53-74% inhibition of tumor growth rate. Fourteen of the 18 patients who ingested SV daily for 2-46 months were included in the analyses; none showed evidence of toxicity. The first lead case remained tumor free for > 133 months; the second case showed complete regression of multiple brain lesions after using SV and radiotherapy. The median survival time of the remaining 12 patients was 33.5 months, and one-year survival was > 70%. The median survival time of the 16 "intent-to-treat" patients (including ineligible patients) was 20 months, and one-year survival was 55%. The Karnofsky performance status of eligible patients was 55 +/- 13 at entry but improved to 92 +/- 9 after use of SV for five months or longer (p < 0.01). Five patients had stable lesions for 30, 30, 20, 12, and 2 months; two of them, whose primary tumor was resected, used SV alone and demonstrated an objective response of their metastatic tumors. In addition to the two lead cases, eight patients had no new metastases after using SV. Three patients had complete regression of brain metastases after using radiotherapy and SV. In this study, daily ingestion of SV was associated with objective responses, prolonged survival, and attenuation of the normal pattern of progression of stage IIIB and IV NSCLC. A large randomized phase III clinical trial is needed to confirm the results observed in this pilot study.

Combined therapy with anti-P-glycoprotein antibody and macrophage colony-stimulating factor gene transduction for multiorgan metastases of multidrug-resistant human small cell lung cancer in NK cell-depleted SCID mice

Our aim was to determine the antimetastatic potential of anti-P-glycoprotein (P-gp) antibodies (Abs) against multidrug-resistant (MDR) human small cell lung cancer (SCLC) cells expressing P-gp. Human SCLC cells H69 (P-gp negative) and its etoposide-resistant variant H69/YP (P-gp positive) were used. H69 and H69/VP cells injected i.v. metastasized to the liver, kidneys and systemic lymph nodes of NK cell-depleted severe combined immunodeficient (SCID) mice. H69/VP cells, but not H69 cells, were resistant to treatments with vindesine. Treatment with mouse-human chimeric anti-P-gp Ab (MH162) and its mouse counterpart (MRK-16) reduced metastasis of H69/VP cells in various organs and prolonged the survival of tumor-bearing mice, although they were less effective if injected at late times (after 28 days). Treatment with another mouse anti-Pgp Ab, MRK-17, was effective only against liver metastasis. MH162 and MRK-16 efficiently induced Ab-dependent cellular cytotoxicity (ADCC) by peritoneal macrophages against H69/VP cells in vitro, but MRK-17 was less effective, in accordance with their in vivo antimetastatic potential. Gene transfection of macrophage colony-stimulating factor (M-CSF) into H69/VP cells to augment macrophage-mediated ADCC resulted in inhibition of metastasis to the liver and lymph nodes, but not kidneys. Combined treatment with a low dose of MRK-16 completely cured metastasis of M-CSF transfectant, but not of the mock transfectant. Our findings suggest that while anti-P-gp Abs had antimetastatic potential against SCLC cells expressing P-gp, combined treatment with M-CSF gene transduction to augment the therapeutic efficacy of anti-P-gp Abs may be beneficial for eradicating metastatic MDR SCLC in humans.

Monocyte chemoattractant protein-1 gene modification of multidrug-resistant human lung cancer enhances antimetastatic effect of therapy with anti-P-glycoprotein antibody in SCID mice

Distant metastases and multidrug resistance are critical problems in the therapy of human small cell lung cancer (SCLC). In this study, we investigated whether transduction of the monocyte chemoattractant protein-1 (MCP-1) gene into multidrug-resistant (MDR) human lung cancer cells affected the formation of metastases or their inhibition by the anti-P-glycoprotein (P-gp) monoclonal antibody (MAb) MRK16. MDR human SCLC (H69/VP) cells were transduced with the human MCP-1 gene inserted into the expression vector BCMGSNeo. MCP-1 gene transduction had no effect on drug sensitivity, the expression of surface antigens or the in vitro proliferation of H69/VP cells. Using the metastatic model of NK cell-depleted SCID mice, H69/VP cells transduced with the MCP-1 gene were inoculated intravenously (i.v.) and formed metastatic colonies in the liver, kidneys and lymph nodes, similar to those formed by parent or mock-transduced cells. However, systemic treatment of the mice with MRK16 reduced the metastases of H69/VP cells in the liver, kidneys and lymph nodes, and was significantly more effective in inhibiting the metastases of MCP-1 producing H69/VP than those of mock-transduced cells. MCP-1 gene transduction significantly prolonged the survival of tumor-bearing mice treated with MRK16. Our findings suggest that local production of MCP-1 in the tumor site increases the anti-P-gp antibody-dependent cell-mediated cytotoxicity, and the MCP-1 gene-induced modification of MDR human SCLC cells thereby enhances the antimetastatic effect of therapy with anti-P-gp antibody. Thus, the accumulation of effector cells in the tumor site is a very important factor in the therapy using the anti-P-gp antibody.

Synergistic antimetastatic effects of lentinan and interleukin 2 with pre- and post-operative treatments

The antimetastatic activity of a combination of lentinan and interleukin 2 (IL-2) was evaluated against spontaneously metastatic 3-methylcholanthrene-induced DBA/2.MC.CS.T fibrosarcoma. Although pre-operative treatment with either IL-2 or lentinan alone exerted little effect on the reduction of lung metastasis colony numbers (7.1% or 28.4% reduction, respectively), the combination exhibited a synergistic effect (85% reduction). Furthermore, 3 of 13 mice given the pre-operative combination treatment achieved complete cure, while no mice given saline did. Although the post-operative combination treatment also reduced the colony number (71% reduction), it caused little prolongation of survival and no mouse achieved complete cure. Synergistic effects were observed between pre- and post-operative treatments with lentinan and IL-2: 8 of 12 mice were completely cured. The anti-metastatic activity was abolished in mice treated simultaneously with antibodies to CD4 and CD8 antigens, whereas either CD4, CD8, or NK1.1 antibody alone was ineffective. Analysis of the cellular mechanism involved in the antimetastatic activity revealed the involvement of a tumor-associated antigen-specific delayed-type hypersensitivity response. These data suggest that the life-prolonging effect of the combination of lentinan and IL-2 is mediated by antigen-specific T cells and that the combination of pre- and post-operative therapy with lentinan and IL-2 may be effective to prevent cancer recurrence and metastasis after surgical resection.

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.

The immunostimulating activities of anti-tumor polysaccharides from Pseudostellaria heterophylla

We have previously shown that a mitogenic fraction (PH-I) separated from Pseudostellaria heterophylla exhibits both immunomodulatory and anti-tumor activities. In the present study, PH-I was further purified by gel filtration chromatography and the resulting three fractions (PH-I A, PH-I B and PH-I C) were assessed for their anti-tumor activity in vivo. It was found that fraction PH-I C from P. heterophylla could markedly suppress the growth of EAT cells in vivo. Mechanistic studies have shown that i.p. injection of PH-I C into mice could enhance the phagocytic activity of thioglycollate-elicited peritoneal macrophages. Moreover, PH-I C showed a potent activating effect on the cytotoxic activity of natural killer (NK) cells and alloreactive cytotoxic T cells (Tc) as well as increased the MurIL-2-induced lymphokine activated killer cell (LAK) activity in vitro. In addition, PH-I C could increase the number of tumor infiltrating lymphocytes (TILs) in the tumor site of WEHI-164-bearing mice. Finally, i.v. injection of PH-I C significantly elevated the levels of IFN-gamma and IL-4 in sera of EAT-bearing mice.

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.

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.

Significant antitumor effect of a synthetic lipid A analogue, DT-5461, on murine syngeneic tumor models

The antitumor effect of a synthetic lipid A analogue, DT-5461, was investigated using syngeneic tumor models in mice. Intravenous injection of DT-5461 into mice transplanted with solid tumors of MethA fibrosarcoma, MH134 hepatoma, MM46 mammary carcinoma, Lewis lung carcinoma (3LL), and colon adenocarcinomas 26 and 38 resulted in significant reductions in the weight of all tumors except Colon 26, with marked hemorrhagic necrosis of tumor tissues. Efficacy was almost equal to that of an Escherichia coli-type synthetic lipid A (compound 506), and also to those of some chemotherapeutics including Adriamycin, mitomycin C, fluorouracil and cisplatin. Furthermore, DT-5461 was more effective than other immunotherapeutics, including picibanil (OK-432) and lentinan. However, its antitumor effects were inferior to those of Adriamycin or OK-432 against the malignant ascites caused by intraperitoneal inoculation with MethA or with MH134 cells; life span was not prolonged by either intraperitoneal or intravenous administration. In addition, although DT-5461 showed direct inhibitory effects on the in vitro growth of MethA or MH134, these were much weaker than those of Adriamycin. These findings clearly indicated that DT-5461 with systemic administration is a highly effective antitumor agent on solid tumors, and suggest that the antitumor effect of DT-5461 with potent necrotizing activity might derive from indirect mechanisms related to the activation of host immune systems and not to the weak direct cytotoxicity.

Augmentation of antimetastatic effect on Lewis lung carcinoma (3LL) in C57BL/6 mice by priming with Lactobacillus casei

The augmentation of the antimetastatic effect of heat-killed cells of Lactobacillus casei YIT9018 (LC9018) on Lewis lung carcinoma (3LL) in C57BL/6 mice by presensitization (priming) with LC9018 was examined. Intralesional injection of LC9018 into 3LL-bearing mice inhibited both the growth of the primary tumors and the formation of lung metastases, and this effect was significantly augmented by subcutaneous injection of LC9018 before the tumor inoculation. In the LC9018-primed mice, intraperitoneal administration of LC9018 into syngeneic hosts after priming induced a high level of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in the peritoneal cavity. At this time, T cells of the spleen cells from the LC9018-primed mice proliferated and produced IL-2 when co-cultured with LC9018 as antigen in vitro. Also, the phenotype of these T cells was found to be L3T4+ and Ly-2.2- T cells by analysis by flow cytometry. These results suggest that LC9018-reactive helper T (Th) cells were induced by the priming and subsequent challenge with LC9018, and that IL-2 or IFN-gamma, which was produced by the activated LC9018-reactive Th cells, augmented a host immune response resulting the antitumor activity.