Tankyrase 1 is a poly(ADP-ribose) polymerase (PARP) which localizes to multiple subcellular sites, including telomeres and mitotic centrosomes. Poly(ADP-ribosyl)ation of the nuclear mitotic apparatus (NuMA) protein by tankyrase 1 during mitosis is essential for sister telomere resolution and mitotic spindle pole formation. In interphase cells, tankyrase 1 resides in the cytoplasm, and its role therein is not well understood. In this study, we found that herpes simplex virus (HSV) infection induced extensive modification of tankyrase 1 but not tankyrase 2. This modification was dependent on extracellular signal-regulated kinase (ERK) activity triggered by HSV infection. Following HSV-1 infection, tankyrase 1 was recruited to the nucleus. In the early phase of infection, tankyrase 1 colocalized with ICP0 and thereafter localized within the HSV replication compartment, which was blocked in cells infected with the HSV-1 ICP0-null mutant R7910. In the absence of infection, ICP0 interacted with tankyrase 1 and efficiently promoted its nuclear localization. HSV did not replicate efficiently in cells depleted of both tankyrases 1 and 2. Moreover, XAV939, an inhibitor of tankyrase PARP activity, decreased viral titers to 2 to 5% of control values. We concluded that HSV targets tankyrase 1 in an ICP0-and ERK-dependent manner to facilitate its replication. Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), members of the Herpesviridae family (17), possess large DNA genomes, share virion structures and replication mechanisms, and establish lifelong latency in host cells. The HSV genome comprises a 152-kb double-stranded DNA molecule that encodes approximately 80 gene products expressed in a temporally regulated cascade (6, 68). HSV genes are classified into three groups: immediate-early, early, and late genes. Immediate-early genes are expressed first upon infection and encode several transactivators, which in turn initiate transcription of the other early and some late genes; the latter are called leaky late or ␥1 genes (12,20,48,73). Early gene products include viral DNA replication factors that initiate viral DNA synthesis, which in turn stimulate expression of ␥1 and true late (␥2) genes, encoding mainly virion structural proteins.The immediate-early viral proteins ICP4, ICP27, ICP0, and ICP22 allow the virus to create an environment conducive to infection and counteract the intrinsic ability of cells to inhibit viral infection (29,34,55,59). ICP4 and ICP27 play essential roles in stimulating robust viral gene expression (34). The immediateearly protein ICP0 activates viral and cellular gene expression and functions as an E3 ubiquitin ligase that degrades several cellular proteins (29). ICP0 targets the promyelocytic leukemia protein (PML), a major component of nuclear foci called ND10 bodies that repress viral gene expression. ICP0 interferes with several intrinsic host defense mechanisms, including the host interferon responses (29), thereby playing a major role in establishing permissive conditions for viral infec...

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Ovarian cancer is the most frequent cause of gynecological cancer-related mortality as a majority of patients are diagnosed at an advanced stage with intraperitoneal dissemination because of the absence of initial symptoms. Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays an important role in the maturation of specialized antigen-presenting cells. In this study, we utilized a herpes simplex virus (HSV) amplicon expressing murine GM-CSF combined with HF10 (mGM-CSF amplicon), a highly attenuated HSV type 1 strain functioning as a helper virus to strengthen anti-tumor immune response, for the treatment of ovarian cancer with intraperitoneal dissemination. A mouse ovarian cancer cell line, OV2944-HM-1 (HM-1), was intraperitoneally injected, following which HF10 only or the mGM-CSF amplicon was injected intraperitoneally three times. HF10 injection prolonged survival and decreased intraperitoneal dissemination, but to a lesser extent than the mGM-CSF amplicon. Although HF10 replication was not observed in HM-1 cells, expression of VP5, a late gene coding the major capsid protein of HSV, was detected. Moreover, mGM-CSF production was detected in transfected HM-1 cells. Immunohistochemical staining revealed the infiltration of CD4-and CD8-positive cells into the peritoneal tumor(s). A significantly increased CD4 1 T cell concentration was observed in the spleen. Murine splenic cells after each treatment were stimulated with HM-1 cells, and the strongest immune response was observed in the mice that received mGM-CSF amplicon injections. These results suggested that the mGM-CSF amplicon is a promising agent for the treatment of advanced ovarian cancer with intraperitoneal dissemination.Ovarian cancer is the most aggressive gynecological cancer and the foremost cause of death from gynecological malignancies in the developed world. 1 However, the lack of effective screening strategies and the absence of symptoms during early disease stages are responsible for the late detection of these tumors, resulting in metastases that primarily spread within the peritoneal cavity. Recent developments in treatment modalities, including wide resection-based surgery and new chemotherapy regimens, have resulted in marked improvement in the short-term survival of ovarian cancer patients. 2 Nevertheless, the long-term prognosis of advanced cases remains unsatisfactory, necessitating a new paradigm in the treatment strategy. Oncolytic viral therapy refers to the use of viruses that selectively replicate in cancer cells.3 It is a promising anticancer therapy because efficient transduction and cancer cellspecific viral replication can boost therapeutic efficacy. Previously, we demonstrated an increase in anti-tumor responses after injection of HF10, a highly attenuated variant of the herpes simplex virus type 1 (HSV-1).4 HF10 was also reported to effectively destroy intraperitoneal disseminated tumors such as colon carcinomas and melanoma in immunocompetent murine models. [5][6][7] The combination of oncolytic HSV with immunosti...

Oncolytic viruses capable of tumor-selective replication and cytolysis have shown early promise as cancer therapeutics. We have developed replication-competent attenuated herpes simplex virus type 1 (HSV-1) mutants, named HF10 and Hh101, which have been evaluated for their oncolytic activities. However, the host immune system remains a significant obstacle to effective intraperitoneal administration of these viruses in the clinical setting. In this study, we investigated the use of these HSV-1 mutants as oncolytic agents against ovarian cancer and the use of human peritoneal mesothelial cells (MCs) as carrier cells for intraperitoneal therapy. MCs were efficiently infected with HSV-1 mutants, and MCs loaded with HSV-1 mutants caused cell killing adequately when cocultured with cancer cells in the presence or absence of HSV antibodies. In a mouse xenograft model of ovarian cancer, the injection of infected carrier cells led to a significant reduction of tumor volume and prolonged survival in comparison with the injection of virus alone. Our results indicate that replication-competent attenuated HSV-1 exerts a potent oncolytic effect on ovarian cancer, which may be further enhanced by the utilization of a carrier cell delivery system, based on amplification of viral load and possibly on avoidance of neutralizing antibodies.

Two strains of birnavirus were isolated from Agemaki (jack knife clam) Sinonovacula constricta originating in the Ariake sea, Japan, and from imported shells from Korea. The genome sequence of the VP2/Ns junction regions of virus genome revealed that the 2 strains are very similar to each other and also similar to other birnaviruses isolated from several marine fishes. Routine survey of the virus ge nome from Agemaki by PCR was performed in 1993 and 1994. The birnavirus genome was detected in high ratios using samples recollected from several fishing grounds where Korean shells were transplant ed. The imported shells from Korea also possessed the virus genome. These findings suggest that birnavi rus is widely present in Agemaki in the Ariake sea and on the Korean coast.