Hayato Ogasawara

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Etoposide (VP-16) is one of the most important anticancer agents available and is used in many chemotherapeutic regimens. To characterize resistance to this drug, we established a VP-16-resistant human ovarian cancer cell line, SKOV3/VP, by continuous stepwise exposure of SKOV3 cells to VP-16. The degree of resistance to VP-16 of SKOV3/VP was about 25 times(More)
The pattern of genome transcription in Escherichia coli determined by controlling the distribution of a total of about 2,000 molecules of RNA polymerase, the transcriptase, among 4,000 genes on its genome. In response to environmental changes, the gene selectivity of the RNA polymerase is modulated after interaction with one sigma subunit, the promoter(More)
In an attempt to develop the most effective cytokine gene therapy, we transfected mouse interleukin(IL)-2, mouse IL-4, and human IL-6 cDNAs into mouse melanoma cells, B16F10. Transfection with IL-4 cDNA decreased the tumorigenicity of B16F10 most strongly. We investigated whether gene therapy with IL-4-transfected B16F10 cells was possible. Flowcytometric(More)
The modulation of gene selectivity of RNA polymerase is the key step in the bacterial response to environmental changes. The gene selectivity of RNA polymerase is modulated after interaction with seven species of sigma factor, the promoter recognition subunit, and a total of about 300 DNA-binding transcription factors in the second step. In order to get(More)
The model bacterium, Escherichia coli, is able to survive under various stressful conditions in nature. From the complete genome sequence, about 4,400 genes are considered to exist on the genome. Selective and regulated expression of the genes is critical for bacterial adaptation to environment. Since the number of RNA polymerase, the enzyme responsible for(More)
Spicamycin (SPM), produced by Streptomyces alanosinicus, induces potent differentiation in a human leukemia cell line, HL6O. One of the derivatives of SPM (SPM-D), KRNS500, has a wide range of antltumor activity against human cancer cell lines. We examined the cytotaxicity of SPM-D in small and non-small cell lung cancer cell lines using(More)
In vivo screening models of a cisplatin (CDDP)-resistant human small-cell lung cancer cell (SCLC) line, H69/CDDP, and a non-small-cell lung cancer cell (NSCLC) line, PC-14/CDDP, were evaluated. The transplantability of the tumor xenografts to SCID mice was more than 90%. Tumor xenografts of H69/CDDP and PC-14/CDDP showed CDDP resistance during in vivo(More)
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