Sae Won Kim

Complete Regression of Metastatic Renal Cell Carcinoma by Multiple Injections of Engineered Mesenchymal Stem Cells Expressing Dodecameric TRAIL and HSV-TK

Purpose: Durable complete remission of metastatic renal cell carcinoma (RCC) has rarely been achieved with current treatment modalities. To solve this problem, alternative therapeutic options with high efficacy and minimal side effects are strongly needed. Experimental Design: Mesenchymal stem cells (MSC) were engineered to coexpress dodecameric TRAIL and herpes simplex virus thymidine kinase (MSC/dTRAIL-TK). The antitumor effects of MSCs expressing dTRAIL (MSC/dTRAIL) or HSV-TK alone (MSC/TK) and MSC/dTRAIL-TK were compared with murine RCC cells using in vitro coculture system and in vivo experimental lung metastasis model. The effects of different doses and schedules of engineered MSCs on mice survival were also evaluated. Results: MSC/dTRAIL-TK exerted stronger apoptotic response in Renca cells than did MSC/TK or MSC/dTRAIL after ganciclovir (GCV) treatment. In vivo imaging results suggest that MSCs reside longer in the lungs of metastatic tumor-bearing mice, compared with that of control mice, regardless of genetic engineering. In addition, MSC/dTRAIL-TK treatment followed by ganciclovir administrations significantly decreased the number of tumor nodules in the lung, to a greater degree than MSC/dTRAIL or MSC/TK, and led to a prolonged survival. More importantly, the antimetastatic effect of MSC/dTRAIL-TK was markedly enhanced by repeated injections but not by increased dose, and resulted in 100% survival of tumor-bearing mice after three injections. Conclusion: Sequential combination gene therapy using MSC/dTRAIL-TK achieved long-term remission of metastatic RCC without noticeable toxicity. Our findings provide an innovative therapeutic approach to completely eradicate metastatic tumors by simple, repeated administrations of MSC/dTRAIL-TK. Clin Cancer Res; 19(2); 415–27. ©2012 AACR.

Crucial Roles of Interleukin-7 in the Development of T Follicular Helper Cells and in the Induction of Humoral Immunity

ABSTRACT T follicular helper (Tfh) cells are specialized providers of cognate B cell help, which is important in promoting the induction of high-affinity antibody production in germinal centers (GCs). Interleukin-6 (IL-6) and IL-21 have been known to play important roles in Tfh cell differentiation. Here, we demonstrate that IL-7 plays a pivotal role in Tfh generation and GC formation in vivo, as treatment with anti-IL-7 neutralizing antibody markedly impaired the development of Tfh cells and IgG responses. Moreover, codelivery of mouse Fc-fused IL-7 (IL-7-mFc) with a vaccine enhanced the generation of GC B cells as well as Tfh cells but not other lineages of T helper cells, including Th1, Th2, and Th17 cells. Interestingly, a 6-fold-lower dose of an influenza virus vaccine codelivered with Fc-fused IL-7 induced higher antigen-specific and cross-reactive IgG titers than the vaccine alone in both mice and monkeys and led to markedly enhanced protection against heterologous influenza virus challenge in mice. Enhanced generation of Tfh cells by IL-7-mFc treatment was not significantly affected by the neutralization of IL-6 and IL-21, indicating an independent role of IL-7 on Tfh differentiation. Thus, IL-7 holds promise as a critical cytokine for selectively inducing Tfh cell generation and enhancing protective IgG responses. IMPORTANCE Here, we demonstrate for the first time that codelivery of Fc-fused IL-7 significantly increased influenza virus vaccine-induced antibody responses, accompanied by robust expansion of Tfh cells and GC B cells as well as enhanced GC formation. Furthermore, IL-7-mFc induced earlier and cross-reactive IgG responses, leading to striking protection against heterologous influenza virus challenge. These results suggest that Fc-fused IL-7 could be used for inducing strong and cross-protective humoral immunity against highly mutable viruses, such as HIV and hepatitis C virus, as well as influenza viruses.

Protective effects of Fc-fused PD-L1 on two different animal models of colitis

Objective Programmed death-ligand 1 (PD-L1) has been shown to negatively regulate immune responses via its interaction with PD-1 receptor. In this study, we investigated the effects of PD-L1-Fc treatment on intestinal inflammation using two murine models of inflammatory colitis induced by dextran sulfate sodium (DSS) and T-cell transfer. Design The anti-colitis effect of adenovirus expressing Fc-conjugated PD-L1 (Ad/PD-L1-Fc) and recombinant PD-L1-Fc protein was evaluated in DSS-treated wild-type and Rag-1 knockout (KO) mice. We examined differentiation of T-helper cells, frequency of innate immune cells, and cytokine production by dendritic cells (DCs) in the colon from DSS-treated mice after PD-L1-Fc administration. In Rag-1 KO mice reconstituted with CD4 CD45RBhigh T cells, we assessed the treatment effect of PD-L1-Fc protein on the development of colitis. Results Administration of Ad/PD-L1-Fc significantly ameliorated DSS-induced colitis, which was accompanied by diminished frequency of interleukin (IL)-17A-producing CD4 T cells and increased interferon-γ-producing CD4 T cells in the colon of DSS-fed mice. The anti-colitic effect of PD-L1-Fc treatment was also observed in DSS-treated Rag-1 KO mice, indicating lymphoid cell independency. PD-L1-Fc modulated cytokine production by colonic DCs and the effect was dependent on PD-1 expression. Furthermore, PD-L1-Fc protein could significantly reduce the severity of colitis in CD4 CD45RBhigh T-cell-transferred Rag-1 KO mice. Conclusions Based on the protective effect of PD-L1-Fc against DSS-induced and T-cell-induced colitis, our results suggest that PD-1-mediated inhibitory signals have a crucial role in limiting the development of colonic inflammation. This implicates that PD-L1-Fc may provide a novel therapeutic approach to treat inflammatory bowel disease.

Enhancement of antigen-specific CD8 T cell responses by co-delivery of Fc-fused CXCL11

Chemokines have been known to play an important role in eliciting adaptive immune responses by, selectively attracting the innate cellular components to the site of antigen presentation. In this study, we demonstrated that all three CXCR3 ligands, CXCL9, CXCL10, and CXCL11, could act as a strong, genetic adjuvant. Among them, CXCL11 increased vaccine antigen-specific CD8 T cells, including, several cytokine secretions (IFN-γ and TNF-α) to a greater degree than the other two CXCR3 ligands. Fc-fusion of CXCL11 (CXCL11-Fc) induced similar but slightly higher CD8 T cell response, which, appeared to be antigen- (ovalbumin (OVA) vs. human papillomavirus 16 (HPV16) E7) and vaccine, type- (adenovirus vs. DNA vaccine) independent. In addition, the adjuvant effect of CXCL11-Fc was, further confirmed by suppressing tumor growth and extension of survival rates in a therapeutic tumor, model, which was correlated with enhanced antigen-specific CD8 T cell responses. Interestingly, the, enhanced antigen-specific CD8 T cell responses by co-delivery of CXCL11-Fc were associated with CD8, T cell proliferation, followed by increased total and effector memory T cell frequencies. Taken together, our findings provide a novel role of CXCL11 as a strong genetic adjuvant which might be used to, increase antigen-specific CD8 T cell immunity elicited by vaccination.

Abstract B012: Preclinical study of Kiatomab, a novel monoclonal antibody to the cancer stem cell surface marker KIAA1114, for anti-cancer therapy in colorectal carcinoma

Most targeted therapy drugs block the growth of cancer cells by targeting specific molecules needed for tumor growth. Among targeted therapy drugs, cetuximab, the monoclonal antibody which binds to epidermal growth factor receptor (EGFR) and inhibits downstream signaling of EGFR, has greatly improved the median survival of patients with metastatic colorectal cancer (CRC). Yet, cetuximab showed limited therapeutic effect in CRC patients who carry certain mutation in the KRAS, which emphasizes the necessity of developing new targeted therapy drugs for CRC. KIA1114 is a full-length protein of the trophinin gene and is localized on the cell surface. In our previous research, we identified the role of KIA1114 as a novel surface marker of tumor initiating cells of hepatocellular carcinoma (HCC) by developing Kiatomab, KIA1114-specific monoclonal antibody. Here, we show that KIA1114 is also highly expressed in various CRC cells with mouse or human origin. Kiatomab treatment inhibits tumor growth in a syngeneic graft CRC mouse model in antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) dependent manner. In the metastatic CRC model, Kiatomab therapy suppresses metastasis, with a significant increase of survival. Of note, the anticancer efficacy of Kiatomab is further improved by combinatorial treatment with the standard chemotherapeutic agent cyclophosphamide (CTX), in both metastatic and solid tumor models. In summary, our findings suggest that KIAA1114 is a new target for CRC and its monoclonal antibody Kiatomab might have a potential for anticancer therapy. Citation Format: Young Min Kim, Sae Won Kim, Seungwon Lee, Hyekang Kim, Ji-Hae Kim, Han Wook Park, Young Chul Sung, Seung-Woo Lee. Preclinical study of Kiatomab, a novel monoclonal antibody to the cancer stem cell surface marker KIAA1114, for anti-cancer therapy in colorectal carcinoma [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B012.