Isolation and characterization of a novel recombinant human adenovirus species D.

A novel recombinant human adenovirus (HAdV) species D was isolated from the stool of a pharyngitis patient in Japan and genetic characterization was performed by sequencing variable regions between HAdV types. The nucleotide sequences of the penton base gene and loops 1 and 2 in the hexon gene showed 100% identity with that of the recently identified HAdV-56. Although we observed greatest identity for the entire hexon gene sequence with that of HAdV-56, we noted even greater similarity between the partial nucleotide sequence of the conserved region 4 and that of HAdV-37. Furthermore, the fibre gene and early region 3 sequences were completely identical to that of HAdV-37. These results suggest that the strain is a novel adenovirus related to HAdV-37 and HAdV-56.

Induction of apoptosis by an inhibitor of EGFR in neuroblastoma cells.

We aimed to examine the expression of EGFR in neuroblastoma tissues and to investigate the antitumor activity of a selective EGFR-tyrosine kinase inhibitor, gefitinib, on neuroblastoma. The expression of EGFR was detected in each of two tumor tissues by immunohistochemistry and eight of 10 cell lines by Western blotting. Gefitinib inhibited EGFR-phosphorylation and in vitro cell growth (IC(50): approximately 1.2 microM), and a high concentration of gefitinib (20-30 microM) induced apoptosis in vitro. This is the first report that EGFR protein is expressed on the cell surface in neuroblastoma tissues and in cell lines. We also demonstrated an EGFR inhibitor induced apoptosis on neuroblastoma cells. Our results suggest the feasibility of targeting EGFR as a novel strategy against neuroblastoma.

A novel synthetic drug, LB-18, closely related to lembehyne-A derived from a marine sponge, induces caspase-independent cell death to human neuroblastoma cells.

Neuroblastoma is a common solid tumor of children that arises from the sympathetic nervous system. Much work has consequently focused on the possibility of inducing marked cell death in neuroblastoma, and the new effective drugs are required. We have newly synthesized LB-18, closely related to lembehyne A (LB-A), a polyacetylene derived from a kind of marine sponge. LB-A has been shown to induce p21/WAF1 and causes G1 phase arrest in mouse neuroblastoma Neuro2A cells; however, we show here that LB-18 causes cell death in human neuroblastoma KP-N-TK cells in a dose-dependent manner. TUNEL assay and flow cytometric analysis showed that the cell death caused by LB-18 was associated with the DNA damage but the pan-caspase inhibitor, zVAD-fmk, could not prevent the cell death. Western blot analysis and cleavage of the caspase-3 or -7 substrate assay showed that LB-18 could not activate caspases 3, 7, 8 and 9. These results suggest that LB-18 causes caspase-independent cell death in human neuroblastoma cells. In the future, LB-18 may be useful for cancer therapeutics, especially for neuroblastoma.

Lysocellin, a metabolite of the novel drug 'alopestatin', induces G1 arrest and prevents cytotoxicity induced by etoposide.

We report here that lysocellin, a polyether antibiotic from a streptomycete, induces G1 phase arrest in human osteosarcoma MG63 cells. Lysocellin up-regulates p21WAF1/Cip1 and down-regulates cyclin D1 at the mRNA level. In addition, cyclin D1 is down-regulated by the proteasome-dependent signal pathway in MG63 cells. In drug combination studies, we found that lysocellin treatment weakened the cytotoxic activity of etoposide in MG63 cells using a colony-formation assay. To study the in vivo efficacy of lysocellin, we isolated a novel compound related to lysocellin from the same streptomycete, and found that the novel drug is converted to lysocellin in vivo and decreases etoposide-induced alopecia in a neonatal rat model. We raise the possibility that this novel drug, named 'alopestatin', may be a promising agent against alopecia.