A CpG oligodeoxynucleotide inducing anti-coxsackie B3 virus activity in human peripheral blood mononuclear cells

Natural Products as a Paradigm for the Treatment of Coxsackievirus - induced Myocarditis

Coxsackievirus B3 (CVB3), a member of the Picornaviridae family, is considered to be one of the most important infectious agents to cause virus-induced myocarditis. Despite improvements in studying viral pathology, structure and molecular biology, as well as diagnosis of this disease, there is still no virus-specific drug in clinical use. Structural and nonstructural proteins produced during the coxsackievirus life cycle have been identified as potential targets for blocking viral replication at the step of attachment, entry, uncoating, RNA and protein synthesis by synthetic or natural compounds. Moreover, WIN (for Winthrop) compounds and application of nucleic-acid based strategies were shown to target viral capsid, entry and viral proteases, but have not reached to the clinical trials as a successful antiviral agent. There is an urgent need for diverse molecular libraries for phenotype-selective and high-throughput screening.

Delivery System of CpG Oligodeoxynucleotides through Eliciting an Effective T cell Immune Response against Melanoma in Mice

Purpose: In order to improve the immunogenicity of whole tumor cell lysate for tumor vaccine, we have designed a series of CpG ODNs to study their transport and to evaluate their anti-tumor activity in B16 melanoma mouse models.

Methods: In this study, we investigated whether C-class CpG ODN (CpG ODN-685) could facilitate tumor cell lysate to induce vigorous anti-tumor activity against tumors in mice both prophylactically and therapeutically.

Results: It was found that the combination of tumor cell lysate and CpG ODN-685 could inhibit the growth of B16 melanoma and prolong the survival of tumor-bearing mice. Moreover CpG ODN-685 with the addition of tumor cell lysate can also cause the generation of tumor specific immune memory by inducing specific cytotoxic T lymphocytes and helper T lymphocytes in mice.

Conclusion: The results suggest that CpG ODN-685 could be developed as an efficient adjuvant for tumor vaccines against melanoma.

In vitro and in vivo protection against enterovirus 71 by an antisense phosphorothioate oligonucleotide

Enterovirus 71 (EV71) is a highly infectious virus that is a major cause of hand, foot, and mouth disease (HFMD), which can lead to severe neurological complications. Currently, there is no effective therapy against EV71. Five antisense oligodeoxynucleotides targeting the 5'-terminal conserved domain of the viral genome were designed using a method based on multiple predicted target mRNA structures. They were then screened for anti-EV71 activity in vitro based on their ability to inhibit an EV71-induced cytopathic effect (CPE). A novel antisense oligonucleotide (EV5) was tested both in rhabdomyosarcoma (RD) cells and in vivo using a mouse model, with a random oligonucleotide (EV5R) of EV5 as a control. EV5 was identified as having significant anti-EV71 activity in vitro and in vivo without significant cytotoxicity. Treatment of RD and Vero cells with antisense oligodeoxynucleotide EV5 significantly and specifically alleviated the cytopathic effect of EV71 in vitro. The inhibitory effect was dose dependent and specific, with a corresponding decrease in viral RNA and viral protein levels. In vivo, EV5 was specifically effective against EV71 virus in preventing death, decreasing weight reduction and reducing the viral RNA copy number and the level of viral proteins in the lungs, intestines and muscles. These results demonstrate the potential and feasibility of using antisense oligodeoxynucleotides specific for the 5'-terminal conserved domain of the viral genome as an antiviral therapy for EV71 disease.

Fully phosphorothioate-modified CpG ODN with PolyG motif inhibits the adhesion of B16 melanoma cells in vitro and tumorigenesis in vivo

Adhesion to the extracellular matrix and endothelial lining of blood vessels is critical for tumor cells to grow at original or metastatic sites. Inhibition of tumor cell adhesion can be an antitumor strategy. Guanosine-rich (G-rich) oligodeoxynucleotides (ODNs) can inhibit the adhesion of certain tumor cells. However, no data exist on how inclusion of the CpG motif in the G-rich sequence influences tumor cell adhesion and subsequent tumorigenesis. In this study, in vitro and in vivo assays were used to evaluate how a panel of ODN-containing contiguous guanosines and the CpG motif influenced adhesion of B16 melanoma cells. The results showed that a self-designed ODN, named BW001, containing the polyG motif and a full phosphorothioate modification backbone could inhibit B16 melanoma cell adhesion on a culture plate or on a plate coated with various substances. In vivo data revealed that B16 melanoma cells co-administered with BW001 and intraperitoneally injected into mice formed fewer tumor colonies in peritoneal cavities. This effect was related to the polyG motif and the full phosphorothioate modification backbone and enhanced by the existence of the CpG motif. Additional in vivo data showed that survival of tumor-bearing mice in the BW001 group was significantly prolonged, subcutaneous melanoma developed much more slowly, and lung dissemination colonies formed much less often than in mice inoculated with B16 melanoma cells only. The effect was CpG motif-dependent. These results suggest that BW001 may exert an integrated antitumor effect.

CpG oligodeoxynucleotides with double stem-loops show strong immunostimulatory activity

Based on the current understanding of TLR9 recognition of CpG ODN, we have tried to design a series of CpG ODNs that display double stem-loops when being analyzed for their secondary structures using 'mfold web server'. Proliferation of human PBMC and bioassay for IFN production were used as technical platforms in primary screening. Interestingly, two of them, designated as DSL01 and D-SL03, belonging to B class CpG ODN and C class CpG ODN respectively, showed vigorous immunostimulatory activity and were chosen for further tests. Flow cytometry analysis showed that both of them could activate human B cells, NK cells, mononuclear cells and T cells and up-regulate expression of CD80, CD86 and HLA-DR on the surface of subsets in human PBMCs. Furthermore, we demonstrated that those two ODNs potently stimulated proliferation of PBMC/splenocytes obtained from diverse vertebrate species. Noticeably, both of them displayed anti-breast cancer effect in mice when administered by peritumoral injection.

Therapeutic injection of C-class CpG ODN in draining lymph node area induces potent activation of immune cells and rejection of established breast cancer in mice

In order to develop novel CpG ODNs for the treatment of breast cancer, we have designed a series of CpG ODNs and evaluated their anti-tumor activity in a breast cancer mouse model. Interestingly, a C-class CpG ODN, designated as YW002, showed a vigorous activity on the inhibition of tumor growth in mice and completely cured some of the tumor-bearing mice through injection at tumor draining lymph node (TDLN) area. The expansion of immune cells in the TDLN and tumor and the generation of tumor specific immune memory were found associated with YW002-induced anti-tumor activity in mice. These results indicate that C-class CpG ODN could be developed into a medicament in a monotherapeutic regimen for the treatment of breast cancer through injection at TDLN area in clinic.