Ionizing radiation causes the massive apoptosis of human tissue cells,leading to dysfunction of the gastrointestinal tract and hematopoietic system.Thus,high-efficiency,low-toxicity radiation protection drugs are urgently needed.Toll-like receptor agonists have been developed based on the anti-apoptotic mechanism of tumor cells in recent years,which exert their radioprotective effects by activating downstream pathways,mainly nuclear factor-κB.Here we elucidate several agonists of Toll-like receptors involved in radiation protection,with an attempt to inform the research and development of new radiation protection agents.
Apoptosis ; Humans ; NF-kappa B ; Radiation Protection ; Radiation, Ionizing ; Radiation-Protective Agents/pharmacology* ; Toll-Like Receptors/agonists*

The aim of study was to explore the potential application of targeting at Toll-like receptors (TLRs) in the immunotherapy of acute myelocytic leukemia, and to investigate the expression of TLR and the effects of TLR 8 agonist ssRNA40/LyoVec on proliferation, apoptosis and cell cycle of U937 cells. The expression of TLR 1 - 9 in U937 cells was detected by using reverse transcription polymerase chain reaction (RT-PCR) and the expression of TLR 8 was assayed by flow cytometry (FCM). The effect of TLR 8 agonist, ssRNA40/LyoVec, at different concentrations on U937 cells proliferation was evaluated by CCK-8, apoptosis and cell cycle were detected by FCM. The results showed that U937 cells expressed TLR 1 - 9. TLR 8 agonist ssRNA40/LyoVec could inhibit the growth of U937 cells both in time-and dose-dependent manner and the inhibitory rate could reach 70%. It also increased the percentage of cells in G(0)/G(1) phase. There was no significant difference in percentage of apoptotic cells between control and treated groups. It is concluded that TLRs including TLR 1 - 9 express on U937 cells and TLR 8 agonist ssRNA40/LyoVec may be able to inhibit the growth of U937 cells, arrest the cells in G(0)/G(1) phase, but have no effect of promoting apoptosis.
Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Reverse Transcriptase Polymerase Chain Reaction ; Toll-Like Receptor 8 ; agonists ; Toll-Like Receptors ; metabolism ; U937 Cells

Dendritic cells (DCs) play a role in natural killer (NK) cell activation, while NK cells are also able to activate and mature DCs. Toll-like receptors (TLRs) on the surface of DCs and NK cells induce the maturation and activation of these cells when engaged with their cognate ligand. We investigated to generate potent DCs by maturation with NK cells in the presence of TLR agonist in vitro and tested the efficacy of these DC vaccinations in mouse colon cancer model. The optimal ratios of DCs versus NK cells were 1:1 to 1:2. Immature DCs were mature with NK cells in the presence of lipopolysaccharide, which is TLR4 agonist, and further addition of IL-2 induced phenotypically and functionally mature bone marrow-derived DCs. These potent DCs exhibited not only high expression of several costimulatory molecules and high production of IL-12p40 and IL-12p70, but also high allogeneic T cells stimulatory capacity, and the induction of the high activities to generate tumor-specific CTLs. Consistently, vaccination with these DCs efficiently inhibited CT-26 tumor growth in mouse colon cancer model when compared to other vaccination strategies. Interestingly, combination therapy of these DC-based vaccines and with low-dose cyclophosphamide showed dramatic inhibition effects of tumor growth. These results suggest that the DCs maturated with NK cells in the presence of TLR agonist are potent inducer of antitumor immune responses in mouse model and may provide a new source of DC-based vaccines for the development of immunotherapy against colon cancer.
Animals ; Cancer Vaccines/immunology/metabolism ; Carcinoma/immunology/pathology/*therapy ; Cell Line, Tumor ; Cells, Cultured ; Colonic Neoplasms/immunology/pathology/*therapy ; Dendritic Cells/*drug effects/*immunology/transplantation ; Female ; Immunotherapy, Adoptive/*methods ; Killer Cells, Natural/*immunology/physiology ; Lipopolysaccharides/pharmacology ; Mice ; Mice, Inbred BALB C ; Toll-Like Receptor 4/agonists ; Toll-Like Receptors/*agonists

Gliomas are extremely aggressive brain tumors with a very poor prognosis. One of the more promising strategies for the treatment of human gliomas is targeted immunotherapy where antigens that are unique to the tumors are exploited to generate vaccines. The approach, however, is complicated by the fact that human gliomas escape immune surveillance by creating an immune suppressed microenvironment. In order to oppose the glioma imposed immune suppression, molecules and pathways involved in immune cell maturation, expansion, and migration are under intensive clinical investigation as adjuvant therapy. Toll-like receptors (TLRs) mediate many of these functions in immune cell types, and TLR agonists, thus, are currently primary candidate molecules to be used as important adjuvants in a variety of cancers. In animal models for glioma, TLR agonists have exhibited antitumor properties by facilitating antigen presentation and stimulating innate and adaptive immunity. In clinical trials, several TLR agonists have achieved survival benefit, and many more trials are recruiting or ongoing. However, a second complicating factor is that TLRs are also expressed on cancer cells where they can participate instead in a variety of tumor promoting activities including cell growth, proliferation, invasion, migration, and even stem cell maintenance. TLR agonists can, therefore, possibly play dual roles in tumor biology. Here, how TLRs and TLR agonists function in glioma biology and in anti-glioma therapies is summarized in an effort to provide a current picture of the sophisticated relationship of glioma with the immune system and the implications for immunotherapy.
Animals ; Antigens, Neoplasm ; chemistry ; immunology ; Antineoplastic Agents ; chemistry ; immunology ; therapeutic use ; Brain Neoplasms ; genetics ; immunology ; pathology ; therapy ; Chemotherapy, Adjuvant ; Clinical Trials as Topic ; Disease Models, Animal ; Gene Expression Regulation, Neoplastic ; drug effects ; immunology ; Glioma ; genetics ; immunology ; pathology ; therapy ; Humans ; Immunotherapy ; methods ; Signal Transduction ; Toll-Like Receptors ; agonists ; genetics ; immunology

We evaluated the effectiveness of rhamnogalacturonan II (RG-II)-stimulated bone marrow-derived dendritic cells (BMDCs) vaccination on the induction of antitumor immunity in a mouse lymphoma model using EG7-lymphoma cells expressing ovalbumin (OVA). BMDCs treated with RG-II had an activated phenotype. RG-II induced interleukin (IL)-12, IL-1beta, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) production during dendritic cell (DC) maturation. BMDCs stimulated with RG-II facilitate the proliferation of CD8+ T cells. Using BMDCs from the mice deficient in Toll-like receptors (TLRs), we revealed that RG-II activity is dependent on TLR4. RG-II showed a preventive effect of immunization with OVA-pulsed BMDCs against EG7 lymphoma. These results suggested that RG-II expedites the DC-based immune response through the TLR4 signaling pathway.
Acute-Phase Proteins/metabolism ; Adaptor Proteins, Vesicular Transport/metabolism ; Animals ; Antigens, CD14/metabolism ; Bone Marrow Cells/cytology/drug effects ; CD8-Positive T-Lymphocytes/*immunology ; Carrier Proteins/metabolism ; Cell Differentiation/drug effects ; Cell Nucleus/drug effects/metabolism ; Cell Proliferation/drug effects ; Cytokines/biosynthesis ; Dendritic Cells/cytology/drug effects/enzymology/*immunology ; Enzyme Activation/drug effects ; Lymphocyte Activation/*drug effects ; Membrane Glycoproteins/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mitogen-Activated Protein Kinases/metabolism ; Myeloid Differentiation Factor 88/metabolism ; NF-kappa B/metabolism ; Neoplasms/immunology/*pathology ; Pectins/*pharmacology ; Phenotype ; Protein Transport/drug effects ; Receptors, Chemokine/metabolism ; Signal Transduction/drug effects ; T-Lymphocytes, Cytotoxic/cytology/drug effects ; Toll-Like Receptor 4/*agonists/metabolism