Byoung Kwon Park

Prevention and therapy of hepatocellular carcinoma by vaccination with TM4SF5 epitope-CpG-DNA-liposome complex without carriers.

Although peptide vaccines have been actively studied in various animal models, their efficacy in treatment is limited. To improve the efficacy of peptide vaccines, we previously formulated an efficacious peptide vaccine without carriers using the natural phosphodiester bond CpG-DNA and a special liposome complex (Lipoplex(O)). Here, we show that immunization of mice with a complex consisting of peptide and Lipoplex(O) without carriers significantly induces peptide-specific IgG2a production in a CD4+ cells- and Th1 differentiation-dependent manner. The transmembrane 4 superfamily member 5 protein (TM4SF5) has gained attention as a target for hepatocellular carcinoma (HCC) therapy because it induces uncontrolled growth of human HCC cells via the loss of contact inhibition. Monoclonal antibodies specific to an epitope of human TM4SF5 (hTM4SF5R2-3) can recognize native mouse TM4SF5 and induce functional effects on mouse cancer cells. Pre-immunization with a complex of the hTM4SF5R2-3 epitope and Lipoplex(O) had prophylactic effects against tumor formation by HCC cells implanted in an mouse tumor model. Furthermore, therapeutic effects were revealed regarding the growth of HCC when the vaccine was injected into mice after tumor formation. These results suggest that our improved peptide vaccine technology provides a novel prophylaxis measure as well as therapy for HCC patients with TM4SF5-positive tumors.

Effect of respiratory syncytial virus on the growth of hepatocellular carcinoma cell-lines.

In several reports, the respiratory syncytial virus (RSV) was identified as an oncolytic virus in cancer cells (e.g., lung and prostate cancer). However, the effects of RSV in hepatocellular carcinoma (HCC) cells have not yet been investigated. Here, we observed the inhibitory effects of RSV infection in HCC cell-lines. Cell growth was significantly decreased by RSV infection in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. After RSV infection, plaque formation and syncytial formation were observed in affected Hep3B and Huh-7 cells. RSV protein-expression was also detected in Hep3B and Huh-7 cells; however, only Huh-7 cells showed apoptosis after RSV infection. Furthermore, inhibition of cell migration by RSV infection was observed in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. Therefore, further investigation is required to clarify the molecular mechanism of RSV-mediated inhibition of HCC cell growth, and to develop potential RSV oncolytic viro-therapeutics. [BMB Reports 2015; 48(10): 565-570]

Monoclonal Antibody Targeting of the Cell Surface Molecule TM4SF5 Inhibits the Growth of Hepatocellular Carcinoma

The cell surface transmembrane receptor TM4SF5 has been implicated in hepatocellular carcinoma (HCC), but its candidacy as a therapeutic target has not been evaluated. Building on findings that immunization with a peptide vaccine targeting human TM4SF5 can exert prophylactic and therapeutic effects in a murine model of HCC, we developed a monoclonal antibody to characterize expression of TM4SF5 in HCC and to target its function there as an anticancer strategy. We found that the antibody modulated cell signaling in HCC cells in vitro, reducing cell motility, modulating E-cadherin expression, altering p27(kip1) localization, and increasing RhoA activity. Using a mouse xenograft model of human HCC, we documented the in vivo efficacy of the antibody, which suppressed tumor growth in either tumor prevention or treatment designs. Our work offers a preclinical proof of concept for TM4SF5 as a promising target for antibody therapeutics to treat HCC. Cancer Res; 74(14); 3844-56. ©2014 AACR.

Induction of immunological memory response by vaccination with TM4SF5 epitope-CpG-DNA-liposome complex in a mouse hepatocellular carcinoma model.

The innovation of a peptide vaccine strategy may contribute to the development of efficacious and convenient cancer vaccines. Recently, we formulated an efficacious peptide vaccine without carriers using the natural phosphodiester bond CpG-DNA and a special liposome complex [Lipoplex(O)]. The peptide vaccine targeting a tumor antigen, transmembrane 4 superfamily member 5 protein (TM4SF5), was confirmed to have preventive and therapeutic effects in a mouse hepatocellular carcinoma (HCC) model. In this study, we demonstrated that the isotype-switched (IgM(-)IgD(-)) B cell population increased after immunization and that the functional memory response persisted for at least 70 days after the final immunization of mice. Delayed implantation of BNL-HCC cells significantly induced the peptide-specific IgG2a production in the immunized mice. Accordingly, tumor growth was inhibited and the survival rate increased. These results suggest that our peptide vaccine induces memory response, which is essential for cancer vaccine application.

Prophylactic effect of a peptide vaccine targeting TM4SF5 against colon cancer in a mouse model

Expression of transmembrane 4 superfamily member 5 protein (TM4SF5) was implicated in hepatocellular carcinoma (HCC) and colon cancer. Previously, we have shown that immunization with TM4SF5 peptide-CpG-DNA-liposome complex induces production of TM4SF5-specific antibodies and protects mice from HCC progression in an allograft model. Here, we confirmed expression of TM4SF5 in the mouse colon cancer cell line CT-26 and found that anti-TM4SF5 antibody inhibits growth of CT-26 cells. We then immunized mice with TM4SF5 peptide-CpG-DNA-liposome complex and transplanted CT-26 cells to investigate the vaccination effects. Robust production of TM4SF5-specific antibodies was induced by challenge with CT-26 cells and the tumor growth was significantly suppressed in the immunized mice. The peptide vaccine targeting TM4SF5 consequently showed a prophylactic effect against colon cancer development in a mouse model. These results suggest that the peptide vaccine can be potentially applied in humans to treat colon cancer.

Effect of epitope-CpG-DNA-liposome complex without carriers on vaccination of respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is a common virus related to disease in the lung epithelium of young children and infants. However, RSV vaccine has not yet been developed. Thus it is difficult to develop a whole-RSV vaccine due to induction of Th2-type hyper-immune responses. To overcome this limitation, we used CpG-DNA encapsulated within liposome complex (Lipoplex(O)) as an adjuvant for the induction of a Th1-dominated humoral response in animal experiments. However, vaccination with a complex of UV-irradiated RSV and Lipoplex(O) had no effect against RSV infection. To improve the efficacy of the RSV vaccine, we performed peptide-based epitope screening and evaluated the efficacy of the vaccine using a complex of epitope and Lipoplex(O). Two efficient B-cell epitopes were identified in nine candidate epitopes from the RSV-F protein. The vaccination with a complex of RSV-F protein epitope (F7 and F9) and Lipoplex(O), induced a prophylactic effect on the RSVinfection based on lung histopathology and mucus clearance from the lungs. Thus, further studies on the effect of the peptide vaccine against infection by multiple RSV strains, may allow fine-tuning of a potential vaccine, and improvement of the vaccine program against RSV.

Anti-metastatic effect of the TM4SF5-specific peptide vaccine and humanized monoclonal antibody on colon cancer in a mouse lung metastasis model

Transmembrane 4 superfamily member 5 protein (TM4SF5) is a potential therapeutic target for hepatocellular carcinoma (HCC) and colon cancer. In a previous study, we demonstrated the prophylactic and therapeutic effects of a TM4SF5-specific peptide vaccine and monoclonal antibody in HCC and colon cancer in a mouse model. Here, we designed a cyclic peptide targeting TM4SF5. Cyclic peptide-specific antibodies were produced in mice after immunization with a complex of the peptide, CpG-DNA, and liposomes. Intravenous injection of the CT-26 mouse colon cancer cell line into mice induced tumors in the lung. Immunization with the peptide vaccine improved the survival rate and reduced the growth of lung tumors. We established a monoclonal antibody specific to the cyclic TM4SF5-based peptide and humanized the antibody sequence by complementarity determining region-grafting. The humanized antibody was reactive to the cyclic peptide and TM4SF5 protein. Treatment of CT-26 cells with the humanized antibody reduced cell motility in vitro. Furthermore, direct injection of the humanized anti-TM4SF5 antibody in vivo reduced growth of lung tumors in mouse metastasis model. Therefore, we conclude that the immunization with the cyclic peptide vaccine and injection of the TM4SF5-specifc humanized antibody have an anti-metastatic effect against colon cancer in mice. Importantly, the humanized antibody may serve as a starting platform for further development and application in clinical settings.

Effects of lipopolysaccharide and CpG-DNA on burn-induced skin injury

Destruction of the skin barrier by thermal injury induces microbial invasion, which can lead to the development of systemic infection and septic shock. Microbial pathogens possess pathogen-associated molecular patterns (PAMPs), which are recognized by conserved receptors. To understand the role of PAMPs in thermal injury-induced mice, LPS or CpG-DNA were topically applied to dorsal skin after thermal injury. We observed an increase in the number of inflammatory cell infiltrates as well as thickening in the dermis upon treatment with LPS or CpG-DNA. We also found that expression of IL-1β, MIP-2, and RANTES induced by thermal injury was enhanced by LPS or CpG-DNA. In addition, the proportions of CD4(+) and CD8(+) T cells in the spleen and lymph nodes were altered by LPS or CpG-DNA. These results provide important information concerning PAMPs-induced inflammation upon thermal injury and provide a basis for studying the role of PAMPs in thermal injury-induced complications.

Extracellular Release of CD11b by TLR9 Stimulation in Macrophages

CpG-DNA upregulates the expression of pro-inflammatory cytokines, chemokines and cell surface markers. Investigators have shown that CD11b (integrin αM) regulates TLR-triggered inflammatory responses in the macrophages and dendritic cells. Therefore, we aimed to identify the effects of CpG-DNA on the expression of CD11b in macrophages. There was no significant change in surface expression of CD11b after CpG-DNA stimulation. However, CD11b was released into culture supernatants after stimulation with phosphorothioate-backbone modified CpG-DNA such as PS-ODN CpG-DNA 1826(S). In contrast, MB-ODN 4531 and non-CpG-DNA control (regardless of backbone type and liposome-encapsulation) failed to induce release of CD11b. Therefore, the context of the CpG-DNA sequence and phosphorothioate backbone modification may regulate the effects of CpG-DNA on CD11b release. Based on inhibitor studies, CD11b release is mediated by p38 MAP kinase activation, but not by the PI3K and NF-κB activation. CD11b release is mediated by lysosomal degradation and by vacuolar acidification in response to CpG-DNA stimulation. The amount of CD11b in the exosome precipitant was significantly increased by CpG-DNA stimulation in vivo and in vitro depending on TLR9. Our observations perhaps give more insight into understanding of the mechanisms involved in CpG-DNA-induced immunomodulation in the innate immunity.

Gomisin G Inhibits the Growth of Triple-Negative Breast Cancer Cells by Suppressing AKT Phosphorylation and Decreasing Cyclin D1

A type of breast cancer with a defect in three molecular markers such as the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor is called triple-negative breast cancer (TNBC). Many patients with TNBC have a lower survival rate than patients with other types due to a poor prognosis. In this study, we confirmed the anti-cancer effect of a natural compound, Gomisin G, in TNBC cancer cells. Treatment with Gomisin G suppressed the viability of two TNBC cell lines, MDA-MB-231 and MDA-MB-468 but not non-TNBC cell lines such as MCF-7, T47D, and ZR75-1. To investigate the molecular mechanism of this activity, we examined the signal transduction pathways after treatment with Gomisin G in MDA-MB-231 cells. Gomisin G did not induce apoptosis but drastically inhibited AKT phosphorylation and reduced the amount of retinoblastoma tumor suppressor protein (Rb) and phosphorylated Rb. Gomisin G induced in a proteasome-dependent manner a decrease in Cyclin D1. Consequently, Gomisin G causes cell cycle arrest in the G1 phase. In contrast, there was no significant change in T47D cells except for a mild decrease in AKT phosphorylation. These results show that Gomisin G has an anti-cancer activity by suppressing proliferation rather than inducing apoptosis in TNBC cells. Our study suggests that Gomisin G could be used as a therapeutic agent in the treatment of TNBC patients.