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664. Therapeutic Effect of Oncolytic Herpes Simplex Virus Type 1 (G47Δ) in Combination with Chemotherapy on Colorectal Cancer
Cancer-Oncolytic Viruses II phagocytosis assays in which target cells were labelled with PKH67. Percentage phagocytosis was determined by the frequency of dual expressing CD15+/PKH67+ cells, relative to total CD15+ cells. We established that the‘high’CD20NALM6 cells generated a significantly greater neutrophil-mediated phagocytic response to rituximab alone than the ‘low’CD20NALM6 cells with a maximum of 57% at E:T ratio of 1:5. Next, we investigated neutrophil-mediated phagocytosis following MV infection. Complement was not added to the medium. At 24 hours post infection with MVNSe, there was only a background level of phagocytosis (<5%) suggesting that neutrophil-mediated phagocytosis is not stimulated by direct microbial recognition in response to MV infection. MVHαCD20 showed similar results, suggesting that the scFVantiCD20 was also unable to stimulate neutrophil-mediated phagocytosis, possibly due to lack of Fc receptor. Studies in the presence of complement are ongoing. Despite the lack of neutrophil-mediated phagocytosis, the overall cell death, as assessed by DAPI staining, was significantly greater after MVHαCD20 infection than after rituximab administration. Future studies into the differential utility of MVHαCD20 over MVNSe in ALL therapy will include work with monocytes and NK cells and co-administration of corticosteroids.
664. Therapeutic Effect of Oncolytic Herpes Simplex Virus Type 1 (G47Δ) in Combination with Chemotherapy on Colorectal Cancer
Shinya Abe1, Yasushi Ino1, Hiroshi Fukuhara2, Miwako Iwai1, Toshiaki Watanabe3, Tomoki Todo1 1 Division of Innovative Cancer Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan, 2Department of Urology, The University of Tokyo, Tokyo, Japan, 3Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan One of the reasons for the difficulty of curing unresectable advanced stage colorectal cancer is that cancer cells acquire resistance to anticancer drugs. Oncolytic virus therapy is a potent candidate for developing a new therapeutic approach that counteracts drug resistance, in which an oncolytic virus kills cancer cells in the course of tumor cell specific viral replication. G47Δ is a third-generation oncolytic herpes simplex virus type 1 with triple mutations in the γ34.5, ICP6, and α47 genes. G47Δ not only destroys cancer cells directly, but also induces systemic antitumor immunity efficiently. In the present study, we investigate the efficacy of G47Δ in combination with 5-fluorouracil (5-FU) or oxaliplatin for colorectal cancer. A human colorectal cancer cell line HCT116 and a murine colorectal cancer cell line CT26 were used in vitro to examine cytotopathic effects and replication capabilities of G47Δ. Combination index analyses demonstrated additive or synergistic effects of G47Δ when used in combination with chemotherapeutic drugs. Importantly, cytotoxic anticancer drugs did not affect the replication capability of G47Δ in vitro. In vivo experiments were performed using BALB/c mice bearing syngeneic subcutaneous CT26 tumors or athymic mice bearing subcutaneous HCT116 tumors. Each established tumor was treated with 2-time intratumoral injections with G47Δ (1×106 pfu) or mock, with concomitant intraperitoneal injections with chemotherapeutic drugs (3mg/kg 5-FU three times or 5mg/kg oxaliplatin four times) or vehicle. Combination therapy inhibited tumor growth significantly better than each therapy alone. Next, we established a 5-FU-resistant CT26 cell line (CT26FuR) by continuously exposing the naive CT26 cells to increasing concentrations of 5-FU. The tolerability of the CT26FuR against 5-FU was confirmed in vitro and in vivo. Cytotopathic effect and replication capability of G47Δ in CT26FuR cells were comparable to those in naive CT26 cells in vitro. Also in vivo, intratumoral administration of G47∆ was as efficacious in subcutaneous CT26FuR tumors as in CT26 tumors. In conclusion,
Molecular Therapy Volume 24, Supplement 1, May 2016 Copyright © The American Society of Gene & Cell Therapy
G47Δ was shown efficacious for colorectal cancer both in vitro and in vivo. G47∆ may be especially useful for the treatment of multi-drug resistant colorectal cancer.
665. Therapeutic Efficacy of Third Generation Oncolytic HSV-1 (G47Δ) for Glioma Cells with Stem Cell Property Hirotaka Ito, Yasushi Ino, Tomoki Todo Division of Innovative Cancer Therapy and Department of Surgical Neuro-Oncology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
Glioblastoma is the most malignant brain tumor with highly dismal prognosis. Recent studies suggest that glioblastoma cells form a subpopulation with stem cell properties, termed glioma initiating cells (GICs). GICs grow less rapidly but are resistant to standard therapies, and are deemed to be a major reason for the disease to be incurable. In this study, the efficacy of G47Δ, a third generation oncolytic herpes simplex virus type 1, was evaluated using GICs established from surgically removed clinical specimens. The GICs grew in vitro as CD133-positive, nestin-positive neurospheres in serum-free medium supplemented with growth factors, and the stemness was confirmed by sphere forming assay. As few as 5x103 GICs implanted in the brain of athymic mice were capable of forming intracerebral tumors that retained histopathological appearances consistent with glioblastoma. On magnetic resonance imaging, the GIC-derived intracerebral tumors appeared as iso intensity in T1 weighted images, high intensity in T2 weighted images, and non contrast-enhanced mass lesions. In in vitro cytotoxicity assays, G47Δ killed 60 to 80% of GICs by day 4 when cells were infected at MOI of 0.01. Infecting GIC spheres with G47Δ caused significant inhibition in secondary sphere formation when compared with mock. In mice harboring GIC-derived intracerebral tumors, a single G47Δ inoculation (8 x 104 pfu, 10 days after tumor implantation) significantly prolonged the survival when compared with mock. Immunohistochemical study of G47Δ injected tumors demonstrated widespread distribution of G47Δ within the tumor but selective to tumor cells. These results indicate that G47Δ efficiently kills GICs as well as non-GIC glioma cells. Taken into account that a phase 2 clinical study with G47∆ in glioblastoma patients is ongoing in Japan, G47∆ may soon become a new therapeutic option for glioma patients with a potential of curing glioblastoma.
666. Oncolytic Herpes Virotherapy Induces a Paracrine Death Signal Causing Synergistic Antitumor Efficacy with Aurora A Kinase Inhibition
Leslee Sprague1, Mark Currier2, Tilat Rizvi3, Brooke Nartker2, Chun-Yu Chen2, Pin-Yi Wang2, Brian Hutzen2, Meghan Franczek2, Jeffrey Ecsedy4, Joe Conner5, Nancy Ratner3, Timothy Cripe2 1 Ohio State University, Columbus, OH, 2Nationwide Children’s Hospital, Columbus, OH, 3Cincinnati Children’s Hospital, Cincinnati, OH, 4Takeda Pharmaceuticals International Co., Cambridge, MA, 5Virttu Biologics, Glasgow, United Kingdom
Aurora A Kinase (AURKA) inhibition with the investigational agent alisertib results in abnormal mitotic progression and the induction of apoptosis in multiple tumor cell lines. Cell cycle arrest is a strategy employed by a variety of viruses, including herpes simplex virus (HSV), to bolster viral reproduction. We previously demonstrated the anti-tumor efficacy of oncolytic HSV and alisertib as monotherapies in models of malignant peripheral nerve sheath tumor (MPNST). We then proceeded to test alisertib and the oncolytic HSV Seprehvir in combination, finding a synergistic anti-tumor effect between the two therapies. Considering this, we hypothesized that alisertib potentiates Seprehvir infection, leading to more rapid S263
664. Therapeutic Effect of Oncolytic Herpes Simplex Virus Type 1 (G47Δ) in Combination with Chemotherapy on Colorectal Cancer
Shinya Abe1, Yasushi Ino1, Hiroshi Fukuhara2, Miwako Iwai1, Toshiaki Watanabe3, Tomoki Todo1 1 Division of Innovative Cancer Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan, 2Department of Urology, The University of Tokyo, Tokyo, Japan, 3Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan One of the reasons for the difficulty of curing unresectable advanced stage colorectal cancer is that cancer cells acquire resistance to anticancer drugs. Oncolytic virus therapy is a potent candidate for developing a new therapeutic approach that counteracts drug resistance, in which an oncolytic virus kills cancer cells in the course of tumor cell specific viral replication. G47Δ is a third-generation oncolytic herpes simplex virus type 1 with triple mutations in the γ34.5, ICP6, and α47 genes. G47Δ not only destroys cancer cells directly, but also induces systemic antitumor immunity efficiently. In the present study, we investigate the efficacy of G47Δ in combination with 5-fluorouracil (5-FU) or oxaliplatin for colorectal cancer. A human colorectal cancer cell line HCT116 and a murine colorectal cancer cell line CT26 were used in vitro to examine cytotopathic effects and replication capabilities of G47Δ. Combination index analyses demonstrated additive or synergistic effects of G47Δ when used in combination with chemotherapeutic drugs. Importantly, cytotoxic anticancer drugs did not affect the replication capability of G47Δ in vitro. In vivo experiments were performed using BALB/c mice bearing syngeneic subcutaneous CT26 tumors or athymic mice bearing subcutaneous HCT116 tumors. Each established tumor was treated with 2-time intratumoral injections with G47Δ (1×106 pfu) or mock, with concomitant intraperitoneal injections with chemotherapeutic drugs (3mg/kg 5-FU three times or 5mg/kg oxaliplatin four times) or vehicle. Combination therapy inhibited tumor growth significantly better than each therapy alone. Next, we established a 5-FU-resistant CT26 cell line (CT26FuR) by continuously exposing the naive CT26 cells to increasing concentrations of 5-FU. The tolerability of the CT26FuR against 5-FU was confirmed in vitro and in vivo. Cytotopathic effect and replication capability of G47Δ in CT26FuR cells were comparable to those in naive CT26 cells in vitro. Also in vivo, intratumoral administration of G47∆ was as efficacious in subcutaneous CT26FuR tumors as in CT26 tumors. In conclusion,
Molecular Therapy Volume 24, Supplement 1, May 2016 Copyright © The American Society of Gene & Cell Therapy
G47Δ was shown efficacious for colorectal cancer both in vitro and in vivo. G47∆ may be especially useful for the treatment of multi-drug resistant colorectal cancer.
665. Therapeutic Efficacy of Third Generation Oncolytic HSV-1 (G47Δ) for Glioma Cells with Stem Cell Property Hirotaka Ito, Yasushi Ino, Tomoki Todo Division of Innovative Cancer Therapy and Department of Surgical Neuro-Oncology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
Glioblastoma is the most malignant brain tumor with highly dismal prognosis. Recent studies suggest that glioblastoma cells form a subpopulation with stem cell properties, termed glioma initiating cells (GICs). GICs grow less rapidly but are resistant to standard therapies, and are deemed to be a major reason for the disease to be incurable. In this study, the efficacy of G47Δ, a third generation oncolytic herpes simplex virus type 1, was evaluated using GICs established from surgically removed clinical specimens. The GICs grew in vitro as CD133-positive, nestin-positive neurospheres in serum-free medium supplemented with growth factors, and the stemness was confirmed by sphere forming assay. As few as 5x103 GICs implanted in the brain of athymic mice were capable of forming intracerebral tumors that retained histopathological appearances consistent with glioblastoma. On magnetic resonance imaging, the GIC-derived intracerebral tumors appeared as iso intensity in T1 weighted images, high intensity in T2 weighted images, and non contrast-enhanced mass lesions. In in vitro cytotoxicity assays, G47Δ killed 60 to 80% of GICs by day 4 when cells were infected at MOI of 0.01. Infecting GIC spheres with G47Δ caused significant inhibition in secondary sphere formation when compared with mock. In mice harboring GIC-derived intracerebral tumors, a single G47Δ inoculation (8 x 104 pfu, 10 days after tumor implantation) significantly prolonged the survival when compared with mock. Immunohistochemical study of G47Δ injected tumors demonstrated widespread distribution of G47Δ within the tumor but selective to tumor cells. These results indicate that G47Δ efficiently kills GICs as well as non-GIC glioma cells. Taken into account that a phase 2 clinical study with G47∆ in glioblastoma patients is ongoing in Japan, G47∆ may soon become a new therapeutic option for glioma patients with a potential of curing glioblastoma.
666. Oncolytic Herpes Virotherapy Induces a Paracrine Death Signal Causing Synergistic Antitumor Efficacy with Aurora A Kinase Inhibition
Leslee Sprague1, Mark Currier2, Tilat Rizvi3, Brooke Nartker2, Chun-Yu Chen2, Pin-Yi Wang2, Brian Hutzen2, Meghan Franczek2, Jeffrey Ecsedy4, Joe Conner5, Nancy Ratner3, Timothy Cripe2 1 Ohio State University, Columbus, OH, 2Nationwide Children’s Hospital, Columbus, OH, 3Cincinnati Children’s Hospital, Cincinnati, OH, 4Takeda Pharmaceuticals International Co., Cambridge, MA, 5Virttu Biologics, Glasgow, United Kingdom
Aurora A Kinase (AURKA) inhibition with the investigational agent alisertib results in abnormal mitotic progression and the induction of apoptosis in multiple tumor cell lines. Cell cycle arrest is a strategy employed by a variety of viruses, including herpes simplex virus (HSV), to bolster viral reproduction. We previously demonstrated the anti-tumor efficacy of oncolytic HSV and alisertib as monotherapies in models of malignant peripheral nerve sheath tumor (MPNST). We then proceeded to test alisertib and the oncolytic HSV Seprehvir in combination, finding a synergistic anti-tumor effect between the two therapies. Considering this, we hypothesized that alisertib potentiates Seprehvir infection, leading to more rapid S263