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Enterovirus infections of the central nervous system (CNS) are common and important causes of morbidity in immunocompromised children and adults. In this study we identify and characterize coxsackievirus B4-induced neuronal death. To investigate the CNS pathophysiology resulting from this viral infection, cultured rat neurons were infected with coxsackievirus B4 (CVB4) and nuclear morphology, phosphatidylserine (PS) externalization, and the effects of Actinomycin D or cycloheximide (CHX) were examined. CVB4 induced neuronal cell death within 24 h while PS externalization was apparent in cell bodies 16 h after CVB4 infection. Actinomycin D or CHX significantly reduced CVB4 induced-neuronal cell death in a dose-dependent manner. Pretreatment with CHX or actinomycin D also inhibited nuclear condensation, which occurred after CVB4 infection. However, the changes were relatively unresponsive to zVAD-fmk. These results suggest that CVB4 induces CHX- and actinomycin D-sensitive, but zVAD-fmk-insensitive neuronal apoptosis. [Copyright &y& Elsevier]

Abstract: RNA interference (RNAi) is a ‘knock-down’ reaction to reduce expression of a specific gene through highly regulated, enzyme-mediated processes. Small interfering RNAs (siRNAs) are RNA molecules that play an effector role in RNAi and can bind the PAZ domains present in Dicer and RISC. We investigated the interaction between the PAZ domain and the siRNA-like duplexes through dissociation molecular dynamics (DMD) simulations. Specifically, we focused on the response of the PAZ domain to various 3′-overhang structures of the siRNA-like duplexes. We found that the siRNA-like duplex with the 3′ UU-overhang made relatively more stable complex with the PAZ domain compared to those with 3′ CC-, AA-, and GG-overhangs. The siRNA-like duplex with UU-overhang was easily dissociated from the PAZ domain once the structural stability of the complex is impaired. Interestingly, the 3′ UU-overhang spent the least time at the periphery region of the binding pocket during the dissociation process, which can be mainly attributable to UU-overhang''s smallest number of hydrogen bonds. [Copyright &y& Elsevier]

Advanced gastric cancer cannot be treated with surgery or conventional cancer therapy, which has prompted a search for new therapeutic modalities. Previously, we and other groups showed that E1B 55 kDa-deleted recombinant adenoviruses, such as YKL-1, effectively replicate and induce cytotoxicity in p53-deficient cancer cells while sparing normal cells. Here, we investigated selective YKL-1 replication and resultant cytolysis in human gastric cancer cells. The cytopathic effects were obvious in all five gastric cancer cell lines we examined. Evaluation of p53 expression indicated that only the AGS cell line retained functionally normal p53. Nevertheless, AGS was 10-fold more sensitive to YKL-1 than the other cell lines. Transmission electron microscopy showed typical morphological alterations along with efficient replication of YKL-1 in AGS cells. Therefore, YKL-1 induces preferential cytotoxic effects in human gastric cancer cells in a p53-independent manner, making YKL-1 a promising therapeutic agent for human gastric cancers. [Copyright &y& Elsevier]

Selectively replicating recombinant adenovirus has emerged as a novel strategy for the treatment of incurable human cancers. One of the major characteristics of hepatocellular carcinoma is the transcriptional reactivation of α-fetoprotein (AFP). In this study, we evaluated the liver cancer-specific oncolytic potential of E1B 55kDa-deleted recombinant adenovirus (YKL-1001), which retained other E1 genes driven by the AFP promoter. Transient transfection study using luciferase indicated the selective activation of the AFP promoter only in human liver cancer cells secreting AFP (HepG2, Hep3B). YKL-1001 induced both cytopathic effects exclusively in AFP-positive liver cancer cells and the growth inhibition of pre-established Hep3B xenografts. Finally, hematoxylin–eosin staining and the immunohistochemistry to the adenoviral hexon showed a large distributed necrotic area and this implied a wide spread of YKL-1001. Therefore, the present study demonstrated that YKL-1001 holds significant promise as an oncolytic agent for hepatocellular carcinoma. [Copyright &y& Elsevier]